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Groups > linux.kernel > #1647066 > unrolled thread
| Started by | David Howells <dhowells@redhat.com> |
|---|---|
| First post | 2017-05-22 18:00 +0200 |
| Last post | 2017-05-22 18:10 +0200 |
| Articles | 17 — 1 participant |
Back to article view | Back to linux.kernel
[RFC][PATCH 00/23] VFS: Introduce superblock configuration context [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 14/23] procfs: Move proc_fill_super() to fs/proc/root.c [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 19/23] NFS: Split nfs_parse_mount_options() [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 12/23] VFS: Implement fsmount() to effect a pre-configured mount [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 07/23] VFS: Introduce the structs and doc for a superblock configuration context [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 17/23] NFS: Constify mount argument match tables [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 09/23] VFS: Implement a superblock configuration context [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 08/23] VFS: Add LSM hooks for superblock configuration context [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 21/23] NFS: Add a small buffer in nfs_sb_config to avoid string dup [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 01/23] Provide a function to create a NUL-terminated string from unterminated data [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 11/23] VFS: Implement fsopen() to prepare for a mount [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 05/23] VFS: Provide empty name qstr [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 22/23] NFS: Do some tidying of the parsing code [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 10/23] VFS: Remove unused code after superblock config context changes [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 03/23] VFS: Make get_mnt_ns() return the namespace [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 13/23] VFS: Add a sample program for fsopen/fsmount [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:00 +0200
[PATCH 06/23] Provide supplementary error message facility [ver #4] David Howells <dhowells@redhat.com> - 2017-05-22 18:10 +0200
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [RFC][PATCH 00/23] VFS: Introduce superblock configuration context [ver #4] |
| Message-ID | <tJXUu-7yP-3@gated-at.bofh.it> |
Here are a set of patches to create a superblock configuration context
prior to setting up a new mount, populating it with the parsed
options/binary data, creating the superblock and then effecting the mount.
This allows namespaces and other information to be conveyed through the
mount procedure. It also allows extra error information to be returned
(so many things can go wrong during a mount that a small integer isn't
really sufficient to convey the issue).
This also allows Miklós Szeredi's idea of doing:
fd = fsopen("nfs");
write(fd, "option=val", ...);
fsmount(fd, "/mnt");
that he presented at LSF-2017 to be implemented (see the relevant patches
in the series), to which I can add:
read(fd, error_buffer, ...);
to read back any error message. I didn't use netlink as that would make it
depend on CONFIG_NET and would introduce network namespacing issues.
I've implemented mount context handling for procfs and nfs.
Significant changes:
ver #4:
(*) Split the sb_config patch up somewhat.
(*) Made the supplementary error string facility something attached to the
task_struct rather than the sb_config so that error messages can be
obtained from NFS doing a mount-root-and-pathwalk inside the
nfs_get_tree() operation.
Further, made this managed and read by prctl rather than through the
mount fd so that it's more generally available.
ver #3:
(*) Rebased on 4.12-rc1.
(*) Split the NFS patch up somewhat.
ver #2:
(*) Removed the ->fill_super() from sb_config_operations and passed it in
directly to functions that want to call it. NFS now calls
nfs_fill_super() directly rather than jumping through a pointer to it
since there's only the one option at the moment.
(*) Removed ->mnt_ns and ->sb from sb_config and moved ->pid_ns into
proc_sb_config.
(*) Renamed create_super -> get_tree.
(*) Renamed struct mount_context to struct sb_config and amended various
variable names.
(*) sys_fsmount() acquired AT_* flags and MS_* flags (for MNT_* flags)
arguments.
ver #1:
(*) Split the sb_config stuff out into its own header.
(*) Support non-context aware filesystems through a special set of
sb_config operations.
(*) Stored the created superblock and root dentry into the sb_config after
creation rather than directly into a vfsmount. This allows some
arguments to be removed to various NFS functions.
(*) Added an explicit superblock-creation step. This allows a created
superblock to then be mounted multiple times.
(*) Added a flag to say that the sb_config is degraded and cannot have
another go at having a superblock creation whilst getting rid of the
one that says it's already mounted.
Further developments:
(*) Implement sb reconfiguration (for now it returns ENOANO).
(*) Implement mount context support in more filesystems, ext4 being next
on my list.
(*) Move the walk-from-root stuff that nfs has to generic code so that you
can do something akin to:
mount /dev/sda1:/foo/bar /mnt
See nfs_follow_remote_path() and mount_subtree(). This is slightly
tricky in NFS as we have to prevent referral loops.
(*) Work out how to get at the error message incurred by submounts
encountered during nfs_follow_remote_path().
Should the error message be moved to task_struct and made more
general, perhaps retrieved with a prctl() function?
(*) Clean up/consolidate the security functions. Possibly add a
validation hook to be called at the same time as the mount context
validate op.
The patches can be found here also:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=mount-context
David
---
David Howells (23):
Provide a function to create a NUL-terminated string from unterminated data
VFS: Clean up whitespace in fs/namespace.c
VFS: Make get_mnt_ns() return the namespace
VFS: Make get_filesystem() return the affected filesystem
VFS: Provide empty name qstr
Provide supplementary error message facility
VFS: Introduce the structs and doc for a superblock configuration context
VFS: Add LSM hooks for superblock configuration context
VFS: Implement a superblock configuration context
VFS: Remove unused code after superblock config context changes
VFS: Implement fsopen() to prepare for a mount
VFS: Implement fsmount() to effect a pre-configured mount
VFS: Add a sample program for fsopen/fsmount
procfs: Move proc_fill_super() to fs/proc/root.c
proc: Add superblock config support to procfs
NFS: Move sb-configuration bits into their own file
NFS: Constify mount argument match tables
NFS: Rename struct nfs_parsed_mount_data to struct nfs_sb_config
NFS: Split nfs_parse_mount_options()
NFS: Deindent nfs_sb_config_parse_option()
NFS: Add a small buffer in nfs_sb_config to avoid string dup
NFS: Do some tidying of the parsing code
NFS: Add sb_config support.
Documentation/filesystems/mounting.txt | 470 ++++++++
arch/x86/entry/syscalls/syscall_32.tbl | 2
arch/x86/entry/syscalls/syscall_64.tbl | 2
fs/Makefile | 3
fs/dcache.c | 8
fs/filesystems.c | 3
fs/fsopen.c | 267 +++++
fs/gfs2/dir.c | 3
fs/internal.h | 4
fs/libfs.c | 17
fs/mount.h | 3
fs/namei.c | 3
fs/namespace.c | 489 +++++++--
fs/nfs/Makefile | 2
fs/nfs/client.c | 74 +
fs/nfs/getroot.c | 72 +
fs/nfs/internal.h | 130 +-
fs/nfs/mount.c | 1499 +++++++++++++++++++++++++++
fs/nfs/namespace.c | 71 +
fs/nfs/nfs3_fs.h | 2
fs/nfs/nfs3client.c | 6
fs/nfs/nfs3proc.c | 2
fs/nfs/nfs4_fs.h | 4
fs/nfs/nfs4client.c | 82 +
fs/nfs/nfs4namespace.c | 208 ++--
fs/nfs/nfs4proc.c | 3
fs/nfs/nfs4super.c | 220 ++--
fs/nfs/proc.c | 2
fs/nfs/super.c | 1785 ++------------------------------
fs/nsfs.c | 3
fs/pipe.c | 3
fs/proc/inode.c | 50 -
fs/proc/internal.h | 6
fs/proc/root.c | 211 +++-
fs/sb_config.c | 512 +++++++++
fs/super.c | 110 +-
include/linux/dcache.h | 5
include/linux/fs.h | 16
include/linux/lsm_hooks.h | 47 +
include/linux/mount.h | 4
include/linux/nfs_xdr.h | 7
include/linux/sb_config.h | 87 ++
include/linux/sched.h | 29 +
include/linux/security.h | 39 +
include/linux/string.h | 1
include/linux/syscalls.h | 3
include/uapi/linux/magic.h | 1
include/uapi/linux/prctl.h | 6
kernel/exit.c | 1
kernel/fork.c | 1
kernel/sys.c | 38 +
kernel/sys_ni.c | 4
mm/util.c | 24
samples/fsmount/test-fsmount.c | 92 ++
security/security.c | 35 +
security/selinux/hooks.c | 201 +++-
56 files changed, 4601 insertions(+), 2371 deletions(-)
create mode 100644 Documentation/filesystems/mounting.txt
create mode 100644 fs/fsopen.c
create mode 100644 fs/nfs/mount.c
create mode 100644 fs/sb_config.c
create mode 100644 include/linux/sb_config.h
create mode 100644 samples/fsmount/test-fsmount.c
[toc] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 14/23] procfs: Move proc_fill_super() to fs/proc/root.c [ver #4] |
| Message-ID | <tJXUv-7yP-31@gated-at.bofh.it> |
| In reply to | #1647066 |
Move proc_fill_super() to fs/proc/root.c as that's where the other
superblock stuff is.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/proc/inode.c | 48 +-----------------------------------------------
fs/proc/internal.h | 4 +---
fs/proc/root.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 49 insertions(+), 51 deletions(-)
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index e250910cffc8..a4bf66af0ba9 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -22,7 +22,6 @@
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/mount.h>
-#include <linux/magic.h>
#include <linux/uaccess.h>
@@ -113,7 +112,7 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root)
return 0;
}
-static const struct super_operations proc_sops = {
+const struct super_operations proc_sops = {
.alloc_inode = proc_alloc_inode,
.destroy_inode = proc_destroy_inode,
.drop_inode = generic_delete_inode,
@@ -470,48 +469,3 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
pde_put(de);
return inode;
}
-
-int proc_fill_super(struct super_block *s, void *data, int silent)
-{
- struct pid_namespace *ns = get_pid_ns(s->s_fs_info);
- struct inode *root_inode;
- int ret;
-
- if (!proc_parse_options(data, ns))
- return -EINVAL;
-
- /* User space would break if executables or devices appear on proc */
- s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
- s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
- s->s_blocksize = 1024;
- s->s_blocksize_bits = 10;
- s->s_magic = PROC_SUPER_MAGIC;
- s->s_op = &proc_sops;
- s->s_time_gran = 1;
-
- /*
- * procfs isn't actually a stacking filesystem; however, there is
- * too much magic going on inside it to permit stacking things on
- * top of it
- */
- s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
-
- pde_get(&proc_root);
- root_inode = proc_get_inode(s, &proc_root);
- if (!root_inode) {
- pr_err("proc_fill_super: get root inode failed\n");
- return -ENOMEM;
- }
-
- s->s_root = d_make_root(root_inode);
- if (!s->s_root) {
- pr_err("proc_fill_super: allocate dentry failed\n");
- return -ENOMEM;
- }
-
- ret = proc_setup_self(s);
- if (ret) {
- return ret;
- }
- return proc_setup_thread_self(s);
-}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index c5ae09b6c726..b681533f59dd 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -197,13 +197,12 @@ struct pde_opener {
struct completion *c;
};
extern const struct inode_operations proc_link_inode_operations;
-
extern const struct inode_operations proc_pid_link_inode_operations;
+extern const struct super_operations proc_sops;
extern void proc_init_inodecache(void);
void set_proc_pid_nlink(void);
extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
-extern int proc_fill_super(struct super_block *, void *data, int flags);
extern void proc_entry_rundown(struct proc_dir_entry *);
/*
@@ -261,7 +260,6 @@ static inline void proc_tty_init(void) {}
* root.c
*/
extern struct proc_dir_entry proc_root;
-extern int proc_parse_options(char *options, struct pid_namespace *pid);
extern void proc_self_init(void);
extern int proc_remount(struct super_block *, int *, char *);
diff --git a/fs/proc/root.c b/fs/proc/root.c
index deecb397daa3..ff2e810e9e64 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -22,6 +22,7 @@
#include <linux/pid_namespace.h>
#include <linux/parser.h>
#include <linux/cred.h>
+#include <linux/magic.h>
#include "internal.h"
@@ -35,7 +36,7 @@ static const match_table_t tokens = {
{Opt_err, NULL},
};
-int proc_parse_options(char *options, struct pid_namespace *pid)
+static int proc_parse_options(char *options, struct pid_namespace *pid)
{
char *p;
substring_t args[MAX_OPT_ARGS];
@@ -77,6 +78,51 @@ int proc_parse_options(char *options, struct pid_namespace *pid)
return 1;
}
+static int proc_fill_super(struct super_block *s, void *data, int silent)
+{
+ struct pid_namespace *ns = get_pid_ns(s->s_fs_info);
+ struct inode *root_inode;
+ int ret;
+
+ if (!proc_parse_options(data, ns))
+ return -EINVAL;
+
+ /* User space would break if executables or devices appear on proc */
+ s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
+ s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
+ s->s_blocksize = 1024;
+ s->s_blocksize_bits = 10;
+ s->s_magic = PROC_SUPER_MAGIC;
+ s->s_op = &proc_sops;
+ s->s_time_gran = 1;
+
+ /*
+ * procfs isn't actually a stacking filesystem; however, there is
+ * too much magic going on inside it to permit stacking things on
+ * top of it
+ */
+ s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
+
+ pde_get(&proc_root);
+ root_inode = proc_get_inode(s, &proc_root);
+ if (!root_inode) {
+ pr_err("proc_fill_super: get root inode failed\n");
+ return -ENOMEM;
+ }
+
+ s->s_root = d_make_root(root_inode);
+ if (!s->s_root) {
+ pr_err("proc_fill_super: allocate dentry failed\n");
+ return -ENOMEM;
+ }
+
+ ret = proc_setup_self(s);
+ if (ret) {
+ return ret;
+ }
+ return proc_setup_thread_self(s);
+}
+
int proc_remount(struct super_block *sb, int *flags, char *data)
{
struct pid_namespace *pid = sb->s_fs_info;
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 19/23] NFS: Split nfs_parse_mount_options() [ver #4] |
| Message-ID | <tJXUv-7yP-43@gated-at.bofh.it> |
| In reply to | #1647066 |
Split nfs_parse_mount_options() to move the prologue, list-splitting and
epilogue into one function and the per-option processing into another.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/nfs/internal.h | 3 +
fs/nfs/mount.c | 143 ++++++++++++++++++++++++++++++-----------------------
2 files changed, 83 insertions(+), 63 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index af6ca28da48d..ed255241baa7 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -100,7 +100,10 @@ struct nfs_sb_config {
unsigned int version;
unsigned int minorversion;
char *fscache_uniq;
+ unsigned short protofamily;
+ unsigned short mountfamily;
bool need_mount;
+ bool sloppy;
struct {
struct sockaddr_storage address;
diff --git a/fs/nfs/mount.c b/fs/nfs/mount.c
index 8f22163a4cc7..99735a494d46 100644
--- a/fs/nfs/mount.c
+++ b/fs/nfs/mount.c
@@ -494,46 +494,18 @@ static int nfs_get_option_ul_bound(substring_t args[], unsigned long *option,
}
/*
- * Error-check and convert a string of mount options from user space into
- * a data structure. The whole mount string is processed; bad options are
- * skipped as they are encountered. If there were no errors, return 1;
- * otherwise return 0 (zero).
+ * Parse a single mount option in "key[=val]" form.
*/
-int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
+static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
{
- char *p, *string, *secdata;
- int rc, sloppy = 0, invalid_option = 0;
- unsigned short protofamily = AF_UNSPEC;
- unsigned short mountfamily = AF_UNSPEC;
-
- if (!raw) {
- dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
- return 1;
- }
- dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
-
- secdata = alloc_secdata();
- if (!secdata)
- goto out_nomem;
-
- rc = security_sb_copy_data(raw, secdata);
- if (rc)
- goto out_security_failure;
-
- rc = security_sb_parse_opts_str(secdata, &cfg->lsm_opts);
- if (rc)
- goto out_security_failure;
-
- free_secdata(secdata);
+ char *string;
+ int rc;
- while ((p = strsep(&raw, ",")) != NULL) {
+ {
substring_t args[MAX_OPT_ARGS];
unsigned long option;
int token;
- if (!*p)
- continue;
-
dfprintk(MOUNT, "NFS: parsing nfs mount option '%s'\n", p);
token = match_token(p, nfs_mount_option_tokens, args);
@@ -737,7 +709,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
if (!rc) {
dfprintk(MOUNT, "NFS: unrecognized "
"security flavor\n");
- return 0;
+ return -EINVAL;
}
break;
case Opt_proto:
@@ -747,22 +719,22 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
token = match_token(string,
nfs_xprt_protocol_tokens, args);
- protofamily = AF_INET;
+ cfg->protofamily = AF_INET;
switch (token) {
case Opt_xprt_udp6:
- protofamily = AF_INET6;
+ cfg->protofamily = AF_INET6;
case Opt_xprt_udp:
cfg->flags &= ~NFS_MOUNT_TCP;
cfg->nfs_server.protocol = XPRT_TRANSPORT_UDP;
break;
case Opt_xprt_tcp6:
- protofamily = AF_INET6;
+ cfg->protofamily = AF_INET6;
case Opt_xprt_tcp:
cfg->flags |= NFS_MOUNT_TCP;
cfg->nfs_server.protocol = XPRT_TRANSPORT_TCP;
break;
case Opt_xprt_rdma6:
- protofamily = AF_INET6;
+ cfg->protofamily = AF_INET6;
case Opt_xprt_rdma:
/* vector side protocols to TCP */
cfg->flags |= NFS_MOUNT_TCP;
@@ -773,7 +745,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
dfprintk(MOUNT, "NFS: unrecognized "
"transport protocol\n");
kfree(string);
- return 0;
+ return -EINVAL;
}
kfree(string);
break;
@@ -785,15 +757,15 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
nfs_xprt_protocol_tokens, args);
kfree(string);
- mountfamily = AF_INET;
+ cfg->mountfamily = AF_INET;
switch (token) {
case Opt_xprt_udp6:
- mountfamily = AF_INET6;
+ cfg->mountfamily = AF_INET6;
case Opt_xprt_udp:
cfg->mount_server.protocol = XPRT_TRANSPORT_UDP;
break;
case Opt_xprt_tcp6:
- mountfamily = AF_INET6;
+ cfg->mountfamily = AF_INET6;
case Opt_xprt_tcp:
cfg->mount_server.protocol = XPRT_TRANSPORT_TCP;
break;
@@ -801,7 +773,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT, "NFS: unrecognized "
"transport protocol\n");
- return 0;
+ return -EINVAL;
}
break;
case Opt_addr:
@@ -860,7 +832,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT, "NFS: invalid "
"lookupcache argument\n");
- return 0;
+ return -EINVAL;
};
break;
case Opt_fscache_uniq:
@@ -893,7 +865,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT, "NFS: invalid "
"local_lock argument\n");
- return 0;
+ return -EINVAL;
};
break;
@@ -901,7 +873,7 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
* Special options
*/
case Opt_sloppy:
- sloppy = 1;
+ cfg->sloppy = 1;
dfprintk(MOUNT, "NFS: relaxing parsing rules\n");
break;
case Opt_userspace:
@@ -911,12 +883,63 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
break;
default:
- invalid_option = 1;
dfprintk(MOUNT, "NFS: unrecognized mount option "
"'%s'\n", p);
+ return -EINVAL;
}
}
+ return 0;
+
+out_invalid_address:
+ printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
+ return -EINVAL;
+out_invalid_value:
+ printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
+ return -EINVAL;
+out_nomem:
+ printk(KERN_INFO "NFS: not enough memory to parse option\n");
+ return -ENOMEM;
+}
+
+/*
+ * Error-check and convert a string of mount options from user space into
+ * a data structure. The whole mount string is processed; bad options are
+ * skipped as they are encountered. If there were no errors, return 1;
+ * otherwise return 0 (zero).
+ */
+int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
+{
+ char *p, *secdata;
+ int rc, sloppy = 0, invalid_option = 0;
+
+ if (!raw) {
+ dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
+ return 1;
+ }
+ dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
+
+ secdata = alloc_secdata();
+ if (!secdata)
+ goto out_nomem;
+
+ rc = security_sb_copy_data(raw, secdata);
+ if (rc)
+ goto out_security_failure;
+
+ rc = security_sb_parse_opts_str(secdata, &cfg->lsm_opts);
+ if (rc)
+ goto out_security_failure;
+
+ free_secdata(secdata);
+
+ while ((p = strsep(&raw, ",")) != NULL) {
+ if (!*p)
+ continue;
+ if (nfs_sb_config_parse_option(cfg, p) < 0)
+ invalid_option = true;
+ }
+
if (!sloppy && invalid_option)
return 0;
@@ -931,22 +954,26 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
* verify that any proto=/mountproto= options match the address
* families in the addr=/mountaddr= options.
*/
- if (protofamily != AF_UNSPEC &&
- protofamily != cfg->nfs_server.address.ss_family)
+ if (cfg->protofamily != AF_UNSPEC &&
+ cfg->protofamily != cfg->nfs_server.address.ss_family)
goto out_proto_mismatch;
- if (mountfamily != AF_UNSPEC) {
+ if (cfg->mountfamily != AF_UNSPEC) {
if (cfg->mount_server.addrlen) {
- if (mountfamily != cfg->mount_server.address.ss_family)
+ if (cfg->mountfamily != cfg->mount_server.address.ss_family)
goto out_mountproto_mismatch;
} else {
- if (mountfamily != cfg->nfs_server.address.ss_family)
+ if (cfg->mountfamily != cfg->nfs_server.address.ss_family)
goto out_mountproto_mismatch;
}
}
return 1;
+out_minorversion_mismatch:
+ printk(KERN_INFO "NFS: mount option vers=%u does not support "
+ "minorversion=%u\n", cfg->version, cfg->minorversion);
+ return 0;
out_mountproto_mismatch:
printk(KERN_INFO "NFS: mount server address does not match mountproto= "
"option\n");
@@ -954,20 +981,10 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
out_proto_mismatch:
printk(KERN_INFO "NFS: server address does not match proto= option\n");
return 0;
-out_invalid_address:
- printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
- return 0;
-out_invalid_value:
- printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
- return 0;
-out_minorversion_mismatch:
- printk(KERN_INFO "NFS: mount option vers=%u does not support "
- "minorversion=%u\n", cfg->version, cfg->minorversion);
- return 0;
out_migration_misuse:
printk(KERN_INFO
"NFS: 'migration' not supported for this NFS version\n");
- return 0;
+ return -EINVAL;
out_nomem:
printk(KERN_INFO "NFS: not enough memory to parse option\n");
return 0;
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 12/23] VFS: Implement fsmount() to effect a pre-configured mount [ver #4] |
| Message-ID | <tJXUv-7yP-45@gated-at.bofh.it> |
| In reply to | #1647066 |
Provide a system call by which a filesystem opened with fsopen() and
configured by a series of writes can be mounted:
int ret = fsmount(int fsfd, int dfd, const char *path,
unsigned int at_flags, unsigned int flags);
where fsfd is the fd returned by fsopen(), dfd, path and at_flags locate
the mountpoint and flags are the applicable MS_* flags. dfd can be
AT_FDCWD or an fd open to a directory.
In the event that fsmount() fails, it may be possible to get an error
message by calling read(). If no message is available, ENODATA will be
reported.
Signed-off-by: David Howells <dhowells@redhat.com>
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/namespace.c | 96 ++++++++++++++++++++++++++++++++
include/linux/lsm_hooks.h | 6 ++
include/linux/security.h | 5 ++
include/linux/syscalls.h | 2 +
kernel/sys_ni.c | 1
security/security.c | 5 ++
security/selinux/hooks.c | 12 ++++
9 files changed, 129 insertions(+)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 9bf8d4c62f85..abe6ea95e0e6 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -392,3 +392,4 @@
383 i386 statx sys_statx
384 i386 arch_prctl sys_arch_prctl compat_sys_arch_prctl
385 i386 fsopen sys_fsopen
+386 i386 fsmount sys_fsmount
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 9b198c5fc412..0977c5079831 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -340,6 +340,7 @@
331 common pkey_free sys_pkey_free
332 common statx sys_statx
333 common fsopen sys_fsopen
+334 common fsmount sys_fsmount
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/namespace.c b/fs/namespace.c
index e92bc48accb5..4e9ad16db79c 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3239,6 +3239,102 @@ vfs_submount(const struct dentry *mountpoint, struct file_system_type *type,
EXPORT_SYMBOL_GPL(vfs_submount);
/*
+ * Mount a new, prepared superblock (specified by fs_fd) on the location
+ * specified by dfd and dir_name. dfd can be AT_FDCWD, a dir fd or a container
+ * fd. This cannot be used for binding, moving or remounting mounts.
+ */
+SYSCALL_DEFINE5(fsmount, int, fs_fd, int, dfd, const char __user *, dir_name,
+ unsigned int, at_flags, unsigned int, flags)
+{
+ struct sb_config *sc;
+ struct inode *inode;
+ struct path mountpoint;
+ struct fd f;
+ unsigned int lookup_flags, mnt_flags = 0;
+ long ret;
+
+ if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
+ AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ if (flags & ~(MS_RDONLY | MS_NOSUID | MS_NODEV | MS_NOEXEC |
+ MS_NOATIME | MS_NODIRATIME | MS_RELATIME | MS_STRICTATIME))
+ return -EINVAL;
+
+ if (flags & MS_RDONLY)
+ mnt_flags |= MNT_READONLY;
+ if (flags & MS_NOSUID)
+ mnt_flags |= MNT_NOSUID;
+ if (flags & MS_NODEV)
+ mnt_flags |= MNT_NODEV;
+ if (flags & MS_NOEXEC)
+ mnt_flags |= MNT_NOEXEC;
+ if (flags & MS_NODIRATIME)
+ mnt_flags |= MNT_NODIRATIME;
+
+ if (flags & MS_STRICTATIME) {
+ if (flags & MS_NOATIME)
+ return -EINVAL;
+ } else if (flags & MS_NOATIME) {
+ mnt_flags |= MNT_NOATIME;
+ } else {
+ mnt_flags |= MNT_RELATIME;
+ }
+
+ f = fdget(fs_fd);
+ if (!f.file)
+ return -EBADF;
+
+ ret = -EINVAL;
+ if (f.file->f_op != &fs_fs_fops)
+ goto err_fsfd;
+
+ sc = f.file->private_data;
+
+ ret = -EPERM;
+ if (!may_mount() ||
+ ((sc->ms_flags & MS_MANDLOCK) && !may_mandlock()))
+ goto err_fsfd;
+
+ /* There must be a valid superblock or we can't mount it */
+ inode = file_inode(f.file);
+ ret = inode_lock_killable(inode);
+ if (ret == 0) {
+ if (!sc->root)
+ ret = invalf("VFS: Root must be obtained before mount");
+ inode_unlock(inode);
+ }
+ if (ret < 0)
+ goto err_fsfd;
+
+ /* Find the mountpoint. A container can be specified in dfd. */
+ lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
+ if (at_flags & AT_SYMLINK_NOFOLLOW)
+ lookup_flags &= ~LOOKUP_FOLLOW;
+ if (at_flags & AT_NO_AUTOMOUNT)
+ lookup_flags &= ~LOOKUP_AUTOMOUNT;
+ if (at_flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+ ret = user_path_at(dfd, dir_name, lookup_flags, &mountpoint);
+ if (ret < 0) {
+ errorf("VFS: Mountpoint lookup failed");
+ goto err_fsfd;
+ }
+
+ ret = security_sb_mountpoint(sc, &mountpoint);
+ if (ret < 0)
+ goto err_mp;
+
+ ret = do_new_mount_sc(sc, &mountpoint, mnt_flags);
+
+err_mp:
+ path_put(&mountpoint);
+err_fsfd:
+ fdput(f);
+ return ret;
+}
+
+/*
* Return true if path is reachable from root
*
* namespace_sem or mount_lock is held
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index e95a918e61ca..7064c0c15386 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -102,6 +102,10 @@
* @sc indicates the superblock configuration context.
* @sc->root indicates the root that will be mounted.
* @sc->root->d_sb points to the superblock.
+ * @sb_mountpoint:
+ * Equivalent of sb_mount, but with an sb_config.
+ * @sc indicates the superblock configuration context.
+ * @mountpoint indicates the path on which the mount will take place.
*
* Security hooks for filesystem operations.
*
@@ -1405,6 +1409,7 @@ union security_list_options {
void (*sb_config_free)(struct sb_config *sc);
int (*sb_config_parse_option)(struct sb_config *sc, char *opt);
int (*sb_get_tree)(struct sb_config *sc);
+ int (*sb_mountpoint)(struct sb_config *sc, struct path *mountpoint);
int (*sb_alloc_security)(struct super_block *sb);
void (*sb_free_security)(struct super_block *sb);
@@ -1721,6 +1726,7 @@ struct security_hook_heads {
struct list_head sb_config_free;
struct list_head sb_config_parse_option;
struct list_head sb_get_tree;
+ struct list_head sb_mountpoint;
struct list_head sb_alloc_security;
struct list_head sb_free_security;
struct list_head sb_copy_data;
diff --git a/include/linux/security.h b/include/linux/security.h
index f6eb735987d1..8c06e158c195 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -230,6 +230,7 @@ int security_sb_config_dup(struct sb_config *sc, struct sb_config *src_sc);
void security_sb_config_free(struct sb_config *sc);
int security_sb_config_parse_option(struct sb_config *sc, char *opt);
int security_sb_get_tree(struct sb_config *sc);
+int security_sb_mountpoint(struct sb_config *sc, struct path *mountpoint);
int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
int security_sb_copy_data(char *orig, char *copy);
@@ -546,6 +547,10 @@ static inline int security_sb_get_tree(struct sb_config *sc)
{
return 0;
}
+static inline int security_sb_mountpoint(struct sb_config *sc, struct path *mountpoint)
+{
+ return 0;
+}
static inline int security_sb_alloc(struct super_block *sb)
{
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 91ec8802ad5d..07e4f775f24d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -906,5 +906,7 @@ asmlinkage long sys_pkey_free(int pkey);
asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
unsigned mask, struct statx __user *buffer);
asmlinkage long sys_fsopen(const char *fs_name, int containerfd, unsigned int flags);
+asmlinkage long sys_fsmount(int fsfd, int dfd, const char *path, unsigned int at_flags,
+ unsigned int flags);
#endif
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index de1dc63e7e47..a0fe764bd5dd 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -261,3 +261,4 @@ cond_syscall(sys_pkey_free);
/* fd-based mount */
cond_syscall(sys_fsopen);
+cond_syscall(sys_fsmount);
diff --git a/security/security.c b/security/security.c
index ed086c6c8f0b..f4136ca5cb1b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -341,6 +341,11 @@ int security_sb_get_tree(struct sb_config *sc)
return call_int_hook(sb_get_tree, 0, sc);
}
+int security_sb_mountpoint(struct sb_config *sc, struct path *mountpoint)
+{
+ return call_int_hook(sb_mountpoint, 0, sc, mountpoint);
+}
+
int security_sb_alloc(struct super_block *sb)
{
return call_int_hook(sb_alloc_security, 0, sb);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 1deafdbf8716..877b7e7bd2d5 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2970,6 +2970,17 @@ static int selinux_sb_get_tree(struct sb_config *sc)
return rc;
}
+static int selinux_sb_mountpoint(struct sb_config *sc, struct path *mountpoint)
+{
+ const struct cred *cred = current_cred();
+ int ret;
+
+ ret = path_has_perm(cred, mountpoint, FILE__MOUNTON);
+ if (ret < 0)
+ errorf("SELinux: Mount on mountpoint not permitted");
+ return ret;
+}
+
/* inode security operations */
static int selinux_inode_alloc_security(struct inode *inode)
@@ -6303,6 +6314,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(sb_config_free, selinux_sb_config_free),
LSM_HOOK_INIT(sb_config_parse_option, selinux_sb_config_parse_option),
LSM_HOOK_INIT(sb_get_tree, selinux_sb_get_tree),
+ LSM_HOOK_INIT(sb_mountpoint, selinux_sb_mountpoint),
LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security),
LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 07/23] VFS: Introduce the structs and doc for a superblock configuration context [ver #4] |
| Message-ID | <tJXUv-7yP-33@gated-at.bofh.it> |
| In reply to | #1647066 |
Introduce a superblock configuration context concept to be used during
superblock creation for mount and superblock reconfiguration for remount.
This is allocated at the beginning of the mount procedure and into it is
placed:
(1) Filesystem type.
(2) Namespaces.
(3) Device name.
(4) Superblock flags (MS_*).
(5) Security details.
(6) Filesystem-specific data, as set by the mount options.
Signed-off-by: David Howells <dhowells@redhat.com>
---
Documentation/filesystems/mounting.txt | 470 ++++++++++++++++++++++++++++++++
include/linux/sb_config.h | 72 +++++
2 files changed, 542 insertions(+)
create mode 100644 Documentation/filesystems/mounting.txt
create mode 100644 include/linux/sb_config.h
diff --git a/Documentation/filesystems/mounting.txt b/Documentation/filesystems/mounting.txt
new file mode 100644
index 000000000000..077ac8352323
--- /dev/null
+++ b/Documentation/filesystems/mounting.txt
@@ -0,0 +1,470 @@
+ ===================
+ FILESYSTEM MOUNTING
+ ===================
+
+CONTENTS
+
+ (1) Overview.
+
+ (2) The superblock configuration context.
+
+ (3) The superblock config operations.
+
+ (4) Superblock config security.
+
+ (5) VFS superblock config operations.
+
+
+========
+OVERVIEW
+========
+
+The creation of new mounts is now to be done in a multistep process:
+
+ (1) Create a superblock configuration context.
+
+ (2) Parse the options and attach them to the context. Options may be passed
+ individually from userspace.
+
+ (3) Validate and pre-process the context.
+
+ (4) Get or create a superblock and mountable root.
+
+ (5) Perform the mount.
+
+ (6) Return an error message attached to the context.
+
+ (7) Destroy the context.
+
+To support this, the file_system_type struct gains two new fields:
+
+ unsigned short sb_config_size;
+
+which indicates the total amount of space that should be allocated for context
+data (see the Superblock Configuration Context section), and:
+
+ int (*init_sb_config)(struct sb_config *sc, struct super_block *src_sb);
+
+which is invoked to set up the filesystem-specific parts of a superblock
+configuration context, including the additional space. The src_sb parameter is
+used to convey the superblock from which the filesystem may draw extra
+information (such as namespaces), for submount (SB_CONFIG_FOR_SUBMOUNT) or
+remount (SB_CONFIG_FOR_REMOUNT) purposes or it will be NULL.
+
+Note that security initialisation is done *after* the filesystem is called so
+that the namespaces may be adjusted first.
+
+And the super_operations struct gains one:
+
+ int (*remount_fs_sc) (struct super_block *, struct sb_config *);
+
+This shadows the ->remount_fs() operation and takes a prepared superblock
+configuration context instead of the mount flags and data page. It may modify
+the ms_flags in the context for the caller to pick up.
+
+[NOTE] remount_fs_sc is intended as a replacement for remount_fs.
+
+
+====================================
+THE SUPERBLOCK CONFIGURATION CONTEXT
+====================================
+
+The creation and reconfiguration of a superblock is governed by a superblock
+configuration context. This is represented by the sb_config structure:
+
+ struct sb_config {
+ const struct sb_config_operations *ops;
+ struct file_system_type *fs;
+ struct dentry *root;
+ struct user_namespace *user_ns;
+ struct net *net_ns;
+ const struct cred *cred;
+ char *device;
+ void *security;
+ const char *error_msg;
+ unsigned int ms_flags;
+ bool sloppy;
+ bool silent;
+ bool degraded;
+ enum mount_type mount_type : 8;
+ };
+
+When the VFS creates this, it allocates ->sb_config_size bytes (as specified by
+the file_system_type object) to hold both the sb_config struct and any extra
+data required by the filesystem. The sb_config struct is placed at the
+beginning of this space. Any extra space beyond that is for use by the
+filesystem. The filesystem should wrap the struct in its own, e.g.:
+
+ struct nfs_sb_config {
+ struct sb_config sc;
+ ...
+ };
+
+placing the sb_config struct first. container_of() can then be used. The
+file_system_type would be initialised thus:
+
+ struct file_system_type nfs = {
+ ...
+ .sb_config_size = sizeof(struct nfs_sb_config),
+ .init_sb_config = nfs_init_sb_config,
+ ...
+ };
+
+The sb_config fields are as follows:
+
+ (*) const struct sb_config_operations *ops
+
+ These are operations that can be done on a superblock configuration
+ context (see below). This must be set by the ->init_sb_config()
+ file_system_type operation.
+
+ (*) struct file_system_type *fs
+
+ A pointer to the file_system_type of the filesystem that is being
+ constructed or reconfigured. This retains a ref on the type owner.
+
+ (*) struct dentry *root
+
+ A pointer to the root of the mountable tree (and indirectly, the
+ superblock thereof). This is filled in by the ->get_tree() op.
+
+ (*) struct user_namespace *user_ns
+ (*) struct net *net_ns
+
+ This is a subset of the namespaces in use by the invoking process. This
+ retains a ref on each namespace. The subscribed namespaces may be
+ replaced by the filesystem to reflect other sources, such as the parent
+ mount superblock on an automount.
+
+ (*) struct cred *cred
+
+ The mounter's credentials. This retains a ref on the credentials.
+
+ (*) char *device
+
+ This is the device to be mounted. It may be a block device
+ (e.g. /dev/sda1) or something more exotic, such as the "host:/path" that
+ NFS desires.
+
+ (*) void *security
+
+ A place for the LSMs to hang their security data for the superblock. The
+ relevant security operations are described below.
+
+ (*) const char *error_msg
+
+ A place for the VFS and the filesystem to hang an error message. This
+ should be in the form of a static string that doesn't need deallocation
+ and the pointer to which can just be overwritten. Under some
+ circumstances, this can be retrieved by userspace.
+
+ Note that the existence of the error string is expected to be guaranteed
+ by the reference on the file_system_type object held by ->fs or any
+ filesystem-specific reference held in the filesystem context until the
+ ->free() operation is called.
+
+ Use sb_cfg_error() and sb_cfg_inval() to set this rather than setting it
+ directly.
+
+ (*) unsigned int ms_flags
+
+ This holds the MS_* flags mount flags.
+
+ (*) bool sloppy
+ (*) bool silent
+
+ These are set if the sloppy or silent mount options are given.
+
+ [NOTE] sloppy is probably unnecessary when userspace passes over one
+ option at a time since the error can just be ignored if userspace deems it
+ to be unimportant.
+
+ [NOTE] silent is probably redundant with ms_flags & MS_SILENT.
+
+ (*) bool degraded
+
+ This is set if any preallocated resources in the configuration have been
+ used up, thereby rendering the configuration unreusable for the
+ ->get_tree() op.
+
+ (*) enum mount_type
+
+ This indicates the type of mount operation. The available values are:
+
+ SB_CONFIG_FOR_NEW -- New mount
+ SB_CONFIG_FOR_SUBMOUNT -- New automatic submount of extant mount
+ SB_CONFIG_FOR_REMOUNT -- Change an existing mount
+
+The mount context is created by calling __vfs_new_sb_config(),
+vfs_new_sb_config(), vfs_sb_reconfig() or vfs_dup_sb_config() and is destroyed
+with put_sb_config(). Note that the structure is not refcounted.
+
+VFS, security and filesystem mount options are set individually with
+vfs_parse_mount_option() or in bulk with generic_monolithic_mount_data().
+
+When mounting, the filesystem is allowed to take data from any of the pointers
+and attach it to the superblock (or whatever), provided it clears the pointer
+in the mount context.
+
+The filesystem is also allowed to allocate resources and pin them with the
+mount context. For instance, NFS might pin the appropriate protocol version
+module.
+
+
+================================
+THE SUPERBLOCK CONFIG OPERATIONS
+================================
+
+The superblock configuration context points to a table of operations:
+
+ struct sb_config_operations {
+ void (*free)(struct sb_config *sc);
+ int (*dup)(struct sb_config *sc, struct sb_config *src_sc);
+ int (*parse_option)(struct sb_config *sc, char *p);
+ int (*monolithic_mount_data)(struct sb_config *sc, void *data);
+ int (*validate)(struct sb_config *sc);
+ int (*get_tree)(struct sb_config *sc);
+ };
+
+These operations are invoked by the various stages of the mount procedure to
+manage the superblock configuration context. They are as follows:
+
+ (*) void (*free)(struct sb_config *sc);
+
+ Called to clean up the filesystem-specific part of the superblock
+ configuration context when the context is destroyed. It should be aware
+ that parts of the context may have been removed and NULL'd out by
+ ->mount().
+
+ (*) int (*dup)(struct sb_config *sc, struct sb_config *src_sc);
+
+ Called when a superblock configuration context has been duplicated to get
+ any refs or copy any non-referenced resources held in the
+ filesystem-specific part of the superblock configuration context. An
+ error may be returned to indicate failure to do this.
+
+ [!] Note that even if this fails, put_sb_config() will be called
+ immediately thereafter, so ->dup() *must* make the filesystem-specific
+ part safe for ->free().
+
+ (*) int (*parse_option)(struct sb_config *sc, char *p);
+
+ Called when an option is to be added to the superblock configuration
+ context. p points to the option string, likely in "key[=val]" format.
+ VFS-specific options will have been weeded out and sc->ms_flags updated in
+ the context. Security options will also have been weeded out and
+ sc->security updated.
+
+ If successful, 0 should be returned and a negative error code otherwise.
+ If an ambiguous error (such as -EINVAL) is returned, sb_cfg_error() or
+ sb_cfg_inval() should be used to provide a string that provides more
+ information.
+
+ (*) int (*monolithic_mount_data)(struct sb_config *sc, void *data);
+
+ Called when the mount(2) system call is invoked to pass the entire data
+ page in one go. If this is expected to be just a list of "key[=val]"
+ items separated by commas, then this may be set to NULL.
+
+ The return value is as for ->parse_option().
+
+ If the filesystem (eg. NFS) needs to examine the data first and then
+ finds it's the standard key-val list then it may pass it off to:
+
+ int generic_monolithic_mount_data(struct sb_config *sc, void *data);
+
+ (*) int (*validate)(struct sb_config *sc);
+
+ Called when all the options have been applied and the mount is about to
+ take place. It is should check for inconsistencies from mount options
+ and it is also allowed to do preliminary resource acquisition. For
+ instance, the core NFS module could load the NFS protocol module here.
+
+ Note that if sc->mount_type == SB_CONFIG_FOR_REMOUNT, some of the options
+ necessary for a new mount may not be set.
+
+ The return value is as for ->parse_option().
+
+ (*) int (*get_tree)(struct sb_config *sc);
+
+ Called to get or create the mountable root and superblock, using the
+ information stored in the superblock configuration context (remounts go
+ via a different vector). It may detach any resources it desires from the
+ superblock configuration context and transfer them to the superblock it
+ creates.
+
+ On success it should set sc->root to the mountable root.
+
+ In the case of an error, it should return a negative error code and
+ consider invoking sb_cfg_inval() or sb_cfg_error().
+
+
+=========================================
+SUPERBLOCK CONFIGURATION CONTEXT SECURITY
+========================================
+
+The superblock configuration context contains a security points that the LSMs can use for
+building up a security context for the superblock to be mounted. There are a
+number of operations used by the new mount code for this purpose:
+
+ (*) int security_sb_config_alloc(struct sb_config *sc,
+ struct super_block *src_sb);
+
+ Called to initialise sc->security (which is preset to NULL) and allocate
+ any resources needed. It should return 0 on success and a negative error
+ code on failure.
+
+ src_sb is non-NULL in the case of a remount (SB_CONFIG_FOR_REMOUNT) in
+ which case it indicates the superblock to be remounted or in the case of a
+ submount (SB_CONFIG_FOR_SUBMOUNT) in which case it indicates the parent
+ superblock.
+
+ (*) int security_sb_config_dup(struct sb_config *sc,
+ struct sb_config *src_mc);
+
+ Called to initialise sc->security (which is preset to NULL) and allocate
+ any resources needed. The original superblock configuration context is pointed to by src_mc
+ and may be used for reference. It should return 0 on success and a
+ negative error code on failure.
+
+ (*) void security_sb_config_free(struct sb_config *sc);
+
+ Called to clean up anything attached to sc->security. Note that the
+ contents may have been transferred to a superblock and the pointer NULL'd
+ out during mount.
+
+ (*) int security_sb_config_parse_option(struct sb_config *sc, char *opt);
+
+ Called for each mount option. The mount options are in "key[=val]"
+ form. An active LSM may reject one with an error, pass one over and
+ return 0 or consume one and return 1. If consumed, the option isn't
+ passed on to the filesystem.
+
+ If it returns an error, more information can be returned with
+ sb_cfg_inval() or sb_cfg_error().
+
+ (*) int security_sb_get_tree(struct sb_config *sc);
+
+ Called during the mount procedure to verify that the specified superblock
+ is allowed to be mounted and to transfer the security data there.
+
+ On success, it should return 0; otherwise it should return an error and
+ perhaps call sb_cfg_inval() or sb_cfg_error() to indicate the problem. It
+ should not return -ENOMEM as this should be taken care of in advance.
+
+ [NOTE] Should I add a security_sb_config_validate() operation so that the
+ LSM has the opportunity to allocate stuff and check the options as a
+ whole?
+
+
+================================
+VFS SUPERBLOCK CONFIG OPERATIONS
+================================
+
+There are four operations for creating a superblock configuration context and
+one for destroying a context:
+
+ (*) struct sb_config *__vfs_new_sb_config(struct file_system_type *fs_type,
+ struct super_block *src_sb;
+ unsigned int ms_flags);
+
+ Create a superblock configuration context given a filesystem type pointer.
+ This allocates the superblock configuration context, sets the flags,
+ initialises the security and calls fs_type->init_sb_config() to initialise
+ the filesystem context.
+
+ src_sb can be NULL or it may indicate a superblock that is going to be
+ remounted (SB_CONFIG_FOR_REMOUNT) or a superblock that is the parent of a
+ submount (SB_CONFIG_FOR_SUBMOUNT). This superblock is provided as a
+ source of namespace information.
+
+ (*) struct sb_config *vfs_sb_reconfig(struct vfsmount *mnt,
+ unsigned int ms_flags);
+
+ Create a superblock configuration context from the same filesystem as an
+ extant mount and initialise the mount parameters from the superblock
+ underlying that mount. This is for use by remount.
+
+ (*) struct sb_config *vfs_new_sb_config(const char *fs_name);
+
+ Create a superblock configuration context given a filesystem name. It is
+ assumed that the mount flags will be passed in as text options or set
+ directly later. This is intended to be called from sys_mount() or
+ sys_fsopen(). This copies current's namespaces to the superblock
+ configuration context.
+
+ (*) struct sb_config *vfs_dup_sb_config(struct sb_config *src_sc);
+
+ Duplicate a superblock configuration context, copying any options noted
+ and duplicating or additionally referencing any resources held therein.
+ This is available for use where a filesystem has to get a mount within a
+ mount, such as NFS4 does by internally mounting the root of the target
+ server and then doing a private pathwalk to the target directory.
+
+ (*) void put_sb_config(struct sb_config *sc);
+
+ Destroy a superblock configuration context, releasing any resources it
+ holds. This calls the ->free() operation. This is intended to be called
+ by anyone who created a superblock configuration context.
+
+ [!] superblock configuration contexts are not refcounted, so this causes
+ unconditional destruction.
+
+In all the above operations, apart from the put op, the return is a mount
+context pointer or a negative error code. No error string is saved as the
+error string is only guaranteed as long as the file_system_type is pinned (and
+thus the module).
+
+The next operations can be used to cache an error message in the context for
+the caller to collect.
+
+ (*) void sb_cfg_error(struct sb_config *sc, const char *msg);
+
+ Set an error message for the caller to pick up. For lifetime rules, see
+ the ->error_msg member description.
+
+ (*) void sb_cfg_inval(struct sb_config *sc, const char *msg);
+
+ As sb_cfg_error(), but returns -EINVAL for use with tail calling.
+
+In the remaining operations, if an error occurs, a negative error code is
+returned and, if not obvious, sc->error_msg may have been set to point to a
+useful string. This string should not be freed.
+
+ (*) int vfs_get_tree(struct sb_config *sc);
+
+ Get or create the mountable root and superblock, using the parameters in
+ the parsed configuration to select/configure the superblock. This invokes
+ the ->validate() op and then the ->get_tree() op.
+
+ [NOTE] ->validate() can probably be rolled into ->get_tree() and
+ ->remount_fs_sc().
+
+ (*) struct vfsmount *vfs_kern_mount_sc(struct sb_config *sc);
+
+ Create a mount given the parameters in the specified superblock
+ configuration context.
+
+ (*) struct vfsmount *vfs_submount_sc(const struct dentry *mountpoint,
+ struct sb_config *sc);
+
+ Create a mount given a superblock configuration context and set
+ MS_SUBMOUNT on it. A wrapper around vfs_kern_mount_sc(). This is
+ intended to be called from filesystems that have automount points (NFS,
+ AFS, ...).
+
+ (*) int vfs_parse_mount_option(struct sb_config *sc, char *data);
+
+ Supply a single mount option to the superblock configuration context. The
+ mount option should likely be in a "key[=val]" string form. The option is
+ first checked to see if it corresponds to a standard mount flag (in which
+ case it is used to mark an MS_xxx flag and consumed) or a security option
+ (in which case the LSM consumes it) before it is passed on to the
+ filesystem.
+
+ (*) int generic_monolithic_mount_data(struct sb_config *sc, void *data);
+
+ Parse a sys_mount() data page, assuming the form to be a text list
+ consisting of key[=val] options separated by commas. Each item in the
+ list is passed to vfs_mount_option(). This is the default when the
+ ->monolithic_mount_data() operation is NULL.
diff --git a/include/linux/sb_config.h b/include/linux/sb_config.h
new file mode 100644
index 000000000000..d2af7342a082
--- /dev/null
+++ b/include/linux/sb_config.h
@@ -0,0 +1,72 @@
+/* Superblock configuration and creation handling.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_SB_CONFIG_H
+#define _LINUX_SB_CONFIG_H
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+
+struct cred;
+struct dentry;
+struct file_operations;
+struct file_system_type;
+struct mnt_namespace;
+struct net;
+struct pid_namespace;
+struct super_block;
+struct user_namespace;
+struct vfsmount;
+
+enum sb_config_purpose {
+ SB_CONFIG_FOR_NEW, /* New superblock for direct mount */
+ SB_CONFIG_FOR_SUBMOUNT, /* New superblock for automatic submount */
+ SB_CONFIG_FOR_REMOUNT, /* Superblock reconfiguration for remount */
+};
+
+/*
+ * Superblock configuration context as allocated and constructed by the
+ * ->init_sb_config() file_system_type operation. The size of the object
+ * allocated is specified in struct file_system_type::sb_config_size and this
+ * must include sufficient space for the sb_config struct.
+ *
+ * Superblock creation fills in ->root whereas reconfiguration begins with this
+ * already set.
+ *
+ * See Documentation/filesystems/mounting.txt
+ */
+struct sb_config {
+ const struct sb_config_operations *ops;
+ struct file_system_type *fs_type;
+ struct dentry *root; /* The root and superblock */
+ struct user_namespace *user_ns; /* The user namespace for this mount */
+ struct net *net_ns; /* The network namespace for this mount */
+ const struct cred *cred; /* The mounter's credentials */
+ char *device; /* The device name or mount target */
+ char *subtype; /* The subtype to set on the superblock */
+ void *security; /* The LSM context */
+ unsigned int ms_flags; /* The superblock flags (MS_*) */
+ bool sloppy; /* Unrecognised options are okay */
+ bool silent;
+ bool degraded; /* True if the config can't be reused */
+ enum sb_config_purpose purpose : 8;
+};
+
+struct sb_config_operations {
+ void (*free)(struct sb_config *sc);
+ int (*dup)(struct sb_config *sc, struct sb_config *src);
+ int (*parse_option)(struct sb_config *sc, char *p);
+ int (*monolithic_mount_data)(struct sb_config *sc, void *data);
+ int (*validate)(struct sb_config *sc);
+ int (*get_tree)(struct sb_config *sc);
+};
+
+#endif /* _LINUX_SB_CONFIG_H */
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 17/23] NFS: Constify mount argument match tables [ver #4] |
| Message-ID | <tJXUv-7yP-49@gated-at.bofh.it> |
| In reply to | #1647066 |
The mount argument match tables should never be altered so constify them.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/nfs/mount.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/mount.c b/fs/nfs/mount.c
index 3e2fe57b9b07..a41f034aafb2 100644
--- a/fs/nfs/mount.c
+++ b/fs/nfs/mount.c
@@ -197,7 +197,7 @@ enum {
Opt_lookupcache_err
};
-static match_table_t nfs_lookupcache_tokens = {
+static const match_table_t nfs_lookupcache_tokens = {
{ Opt_lookupcache_all, "all" },
{ Opt_lookupcache_positive, "pos" },
{ Opt_lookupcache_positive, "positive" },
@@ -213,7 +213,7 @@ enum {
Opt_local_lock_err
};
-static match_table_t nfs_local_lock_tokens = {
+static const match_table_t nfs_local_lock_tokens = {
{ Opt_local_lock_all, "all" },
{ Opt_local_lock_flock, "flock" },
{ Opt_local_lock_posix, "posix" },
@@ -229,7 +229,7 @@ enum {
Opt_vers_err
};
-static match_table_t nfs_vers_tokens = {
+static const match_table_t nfs_vers_tokens = {
{ Opt_vers_2, "2" },
{ Opt_vers_3, "3" },
{ Opt_vers_4, "4" },
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 09/23] VFS: Implement a superblock configuration context [ver #4] |
| Message-ID | <tJXUv-7yP-29@gated-at.bofh.it> |
| In reply to | #1647066 |
Implement a superblock configuration context concept to be used during
superblock creation for mount and superblock reconfiguration for remount.
The mounting procedure then becomes:
(1) Allocate new sb_config context.
(2) Configure the context.
(3) Create superblock.
(4) Mount the superblock any number of times.
(5) Destroy the context.
Rather than calling fs_type->mount(), an sb_config struct is created and
fs_type->init_sb_config() is called to set it up. fs_type->sb_config_size
says how much space should be allocated for the config context. The
sb_config struct is placed at the beginning and any extra space is for the
filesystem's use.
A set of operations has to be set by ->init_sb_config() to provide freeing,
duplication, option parsing, binary data parsing, validation, mounting and
superblock filling.
Legacy filesystems are supported by the provision of a set of legacy
sb_config operations that build up a list of mount options and then invoke
fs_type->mount() from within the sb_config ->get_tree() operation. This
allows all filesystems to be accessed using sb_config.
It should be noted that, whilst this patch adds a lot of lines of code,
there is quite a bit of duplication with existing code that can be
eliminated should all filesystems be converted over.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/Makefile | 3
fs/internal.h | 2
fs/libfs.c | 17 +
fs/namespace.c | 389 ++++++++++++++++++++++++++--------
fs/sb_config.c | 512 +++++++++++++++++++++++++++++++++++++++++++++
fs/super.c | 57 +++++
include/linux/fs.h | 14 +
include/linux/mount.h | 4
include/linux/sb_config.h | 13 +
9 files changed, 907 insertions(+), 104 deletions(-)
create mode 100644 fs/sb_config.c
diff --git a/fs/Makefile b/fs/Makefile
index 7bbaca9c67b1..8f5142525866 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -11,7 +11,8 @@ obj-y := open.o read_write.o file_table.o super.o \
attr.o bad_inode.o file.o filesystems.o namespace.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o splice.o sync.o utimes.o \
- stack.o fs_struct.o statfs.o fs_pin.o nsfs.o
+ stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
+ sb_config.o
ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o block_dev.o direct-io.o mpage.o
diff --git a/fs/internal.h b/fs/internal.h
index 9676fe11c093..39121a99d930 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -87,7 +87,7 @@ extern struct file *get_empty_filp(void);
/*
* super.c
*/
-extern int do_remount_sb(struct super_block *, int, void *, int);
+extern int do_remount_sb(struct super_block *, int, void *, int, struct sb_config *);
extern bool trylock_super(struct super_block *sb);
extern struct dentry *mount_fs(struct file_system_type *,
int, const char *, void *);
diff --git a/fs/libfs.c b/fs/libfs.c
index a04395334bb1..e8787adf0363 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -9,6 +9,7 @@
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/mount.h>
+#include <linux/sb_config.h>
#include <linux/vfs.h>
#include <linux/quotaops.h>
#include <linux/mutex.h>
@@ -574,13 +575,27 @@ static DEFINE_SPINLOCK(pin_fs_lock);
int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
{
+ struct sb_config *sc;
struct vfsmount *mnt = NULL;
+ int ret;
+
spin_lock(&pin_fs_lock);
if (unlikely(!*mount)) {
spin_unlock(&pin_fs_lock);
- mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
+
+ sc = __vfs_new_sb_config(type, NULL, MS_KERNMOUNT, SB_CONFIG_FOR_NEW);
+ if (IS_ERR(sc))
+ return PTR_ERR(sc);
+
+ ret = vfs_get_tree(sc);
+ if (ret < 0)
+ return ret;
+
+ mnt = vfs_kern_mount_sc(sc);
+ put_sb_config(sc);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
+
spin_lock(&pin_fs_lock);
if (!*mount)
*mount = mnt;
diff --git a/fs/namespace.c b/fs/namespace.c
index c076787871e7..e92bc48accb5 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -25,7 +25,9 @@
#include <linux/magic.h>
#include <linux/bootmem.h>
#include <linux/task_work.h>
+#include <linux/file.h>
#include <linux/sched/task.h>
+#include <linux/sb_config.h>
#include "pnode.h"
#include "internal.h"
@@ -957,55 +959,6 @@ static struct mount *skip_mnt_tree(struct mount *p)
return p;
}
-struct vfsmount *
-vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
-{
- struct mount *mnt;
- struct dentry *root;
-
- if (!type)
- return ERR_PTR(-ENODEV);
-
- mnt = alloc_vfsmnt(name);
- if (!mnt)
- return ERR_PTR(-ENOMEM);
-
- if (flags & MS_KERNMOUNT)
- mnt->mnt.mnt_flags = MNT_INTERNAL;
-
- root = mount_fs(type, flags, name, data);
- if (IS_ERR(root)) {
- mnt_free_id(mnt);
- free_vfsmnt(mnt);
- return ERR_CAST(root);
- }
-
- mnt->mnt.mnt_root = root;
- mnt->mnt.mnt_sb = root->d_sb;
- mnt->mnt_mountpoint = mnt->mnt.mnt_root;
- mnt->mnt_parent = mnt;
- lock_mount_hash();
- list_add_tail(&mnt->mnt_instance, &root->d_sb->s_mounts);
- unlock_mount_hash();
- return &mnt->mnt;
-}
-EXPORT_SYMBOL_GPL(vfs_kern_mount);
-
-struct vfsmount *
-vfs_submount(const struct dentry *mountpoint, struct file_system_type *type,
- const char *name, void *data)
-{
- /* Until it is worked out how to pass the user namespace
- * through from the parent mount to the submount don't support
- * unprivileged mounts with submounts.
- */
- if (mountpoint->d_sb->s_user_ns != &init_user_ns)
- return ERR_PTR(-EPERM);
-
- return vfs_kern_mount(type, MS_SUBMOUNT, name, data);
-}
-EXPORT_SYMBOL_GPL(vfs_submount);
-
static struct mount *clone_mnt(struct mount *old, struct dentry *root,
int flag)
{
@@ -1593,7 +1546,7 @@ static int do_umount(struct mount *mnt, int flags)
return -EPERM;
down_write(&sb->s_umount);
if (!(sb->s_flags & MS_RDONLY))
- retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
+ retval = do_remount_sb(sb, MS_RDONLY, NULL, 0, NULL);
up_write(&sb->s_umount);
return retval;
}
@@ -2276,6 +2229,20 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
}
/*
+ * Parse the monolithic page of mount data given to sys_mount().
+ */
+static int parse_monolithic_mount_data(struct sb_config *sc, void *data)
+{
+ int (*monolithic_mount_data)(struct sb_config *, void *);
+
+ monolithic_mount_data = sc->ops->monolithic_mount_data;
+ if (!monolithic_mount_data)
+ monolithic_mount_data = generic_monolithic_mount_data;
+
+ return monolithic_mount_data(sc, data);
+}
+
+/*
* change filesystem flags. dir should be a physical root of filesystem.
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
@@ -2283,9 +2250,11 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
static int do_remount(struct path *path, int flags, int mnt_flags,
void *data)
{
+ struct sb_config *sc = NULL;
int err;
struct super_block *sb = path->mnt->mnt_sb;
struct mount *mnt = real_mount(path->mnt);
+ struct file_system_type *type = sb->s_type;
if (!check_mnt(mnt))
return -EINVAL;
@@ -2320,9 +2289,19 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
return -EPERM;
}
- err = security_sb_remount(sb, data);
- if (err)
- return err;
+ if (type->init_sb_config) {
+ sc = vfs_sb_reconfig(path->mnt, flags);
+ if (IS_ERR(sc))
+ return PTR_ERR(sc);
+
+ err = parse_monolithic_mount_data(sc, data);
+ if (err < 0)
+ goto err_sc;
+ } else {
+ err = security_sb_remount(sb, data);
+ if (err)
+ return err;
+ }
down_write(&sb->s_umount);
if (flags & MS_BIND)
@@ -2330,7 +2309,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
else if (!capable(CAP_SYS_ADMIN))
err = -EPERM;
else
- err = do_remount_sb(sb, flags, data, 0);
+ err = do_remount_sb(sb, flags, data, 0, sc);
if (!err) {
lock_mount_hash();
mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
@@ -2339,6 +2318,9 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
unlock_mount_hash();
}
up_write(&sb->s_umount);
+err_sc:
+ if (sc)
+ put_sb_config(sc);
return err;
}
@@ -2422,29 +2404,6 @@ static int do_move_mount(struct path *path, const char *old_name)
return err;
}
-static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
-{
- int err;
- const char *subtype = strchr(fstype, '.');
- if (subtype) {
- subtype++;
- err = -EINVAL;
- if (!subtype[0])
- goto err;
- } else
- subtype = "";
-
- mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
- err = -ENOMEM;
- if (!mnt->mnt_sb->s_subtype)
- goto err;
- return mnt;
-
- err:
- mntput(mnt);
- return ERR_PTR(err);
-}
-
/*
* add a mount into a namespace's mount tree
*/
@@ -2492,40 +2451,80 @@ static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags)
static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags);
/*
+ * Create a new mount using a superblock configuration and request it
+ * be added to the namespace tree.
+ */
+static int do_new_mount_sc(struct sb_config *sc, struct path *mountpoint,
+ unsigned int mnt_flags)
+{
+ struct vfsmount *mnt;
+ int ret;
+
+ mnt = vfs_kern_mount_sc(sc);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+
+ ret = -EPERM;
+ if (mount_too_revealing(mnt, &mnt_flags)) {
+ errorf("VFS: Mount too revealing");
+ goto err_mnt;
+ }
+
+ ret = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
+ if (ret < 0) {
+ errorf("VFS: Failed to add mount");
+ goto err_mnt;
+ }
+ return ret;
+
+err_mnt:
+ mntput(mnt);
+ return ret;
+}
+
+/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
*/
-static int do_new_mount(struct path *path, const char *fstype, int flags,
+static int do_new_mount(struct path *mountpoint, const char *fstype, int flags,
int mnt_flags, const char *name, void *data)
{
- struct file_system_type *type;
- struct vfsmount *mnt;
+ struct sb_config *sc;
int err;
if (!fstype)
return -EINVAL;
- type = get_fs_type(fstype);
- if (!type)
- return -ENODEV;
+ sc = vfs_new_sb_config(fstype);
+ if (IS_ERR(sc)) {
+ err = PTR_ERR(sc);
+ goto err;
+ }
+ sc->ms_flags = flags;
- mnt = vfs_kern_mount(type, flags, name, data);
- if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
- !mnt->mnt_sb->s_subtype)
- mnt = fs_set_subtype(mnt, fstype);
+ err = -ENOMEM;
+ sc->device = kstrdup(name, GFP_KERNEL);
+ if (!sc->device)
+ goto err_sc;
- put_filesystem(type);
- if (IS_ERR(mnt))
- return PTR_ERR(mnt);
+ err = parse_monolithic_mount_data(sc, data);
+ if (err < 0)
+ goto err_sc;
- if (mount_too_revealing(mnt, &mnt_flags)) {
- mntput(mnt);
- return -EPERM;
- }
+ err = vfs_get_tree(sc);
+ if (err < 0)
+ goto err_sc;
- err = do_add_mount(real_mount(mnt), path, mnt_flags);
+ err = do_new_mount_sc(sc, mountpoint, mnt_flags);
if (err)
- mntput(mnt);
+ goto err_sc;
+
+ put_sb_config(sc);
+ return 0;
+
+err_sc:
+ put_sb_config(sc);
+err:
return err;
}
@@ -3058,6 +3057,187 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
return ret;
}
+/**
+ * vfs_get_tree - Get the mountable root
+ * @sc: The superblock configuration context.
+ *
+ * The filesystem is invoked to get or create a superblock which can then later
+ * be used for mounting. The filesystem places a pointer to the root to be
+ * used for mounting in @sc->root.
+ */
+int vfs_get_tree(struct sb_config *sc)
+{
+ struct super_block *sb;
+ int ret;
+
+ if (sc->root)
+ return -EBUSY;
+
+ if (sc->ops->validate) {
+ ret = sc->ops->validate(sc);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* The filesystem may transfer preallocated resources from the
+ * configuration context to the superblock, thereby rendering the
+ * config unusable for another attempt at creation if this one fails.
+ */
+ if (sc->degraded)
+ return invalf("VFS: The config is degraded");
+
+ /* Get the mountable root in sc->root, with a ref on the root and a ref
+ * on the superblock.
+ */
+ ret = sc->ops->get_tree(sc);
+ if (ret < 0)
+ return ret;
+
+ BUG_ON(!sc->root);
+ sb = sc->root->d_sb;
+ WARN_ON(!sb->s_bdi);
+
+ ret = security_sb_get_tree(sc);
+ if (ret < 0)
+ goto err_sb;
+
+ ret = -ENOMEM;
+ if (sc->subtype && !sb->s_subtype) {
+ sb->s_subtype = kstrdup(sc->subtype, GFP_KERNEL);
+ if (!sb->s_subtype)
+ goto err_sb;
+ }
+
+ sb->s_flags |= MS_BORN;
+
+ /* Filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
+ * but s_maxbytes was an unsigned long long for many releases. Throw
+ * this warning for a little while to try and catch filesystems that
+ * violate this rule.
+ */
+ WARN(sb->s_maxbytes < 0,
+ "%s set sb->s_maxbytes to negative value (%lld)\n",
+ sc->fs_type->name, sb->s_maxbytes);
+
+ up_write(&sb->s_umount);
+ return 0;
+
+err_sb:
+ dput(sc->root);
+ sc->root = NULL;
+ deactivate_locked_super(sb);
+ return ret;
+}
+EXPORT_SYMBOL(vfs_get_tree);
+
+/**
+ * vfs_kern_mount_sc - Create a mount for a configured superblock
+ * sc: The configuration context with the superblock attached
+ *
+ * Create a mount to an already configured superblock. If necessary, the
+ * caller should invoke vfs_create_super() before calling this.
+ */
+struct vfsmount *vfs_kern_mount_sc(struct sb_config *sc)
+{
+ struct mount *mnt;
+
+ if (!sc->root)
+ return ERR_PTR(invalf("VFS: Root must be obtained before mount"));
+
+ mnt = alloc_vfsmnt(sc->device ?: "none");
+ if (!mnt)
+ return ERR_PTR(-ENOMEM);
+
+ if (sc->ms_flags & MS_KERNMOUNT)
+ mnt->mnt.mnt_flags = MNT_INTERNAL;
+
+ atomic_inc(&sc->root->d_sb->s_active);
+ mnt->mnt.mnt_sb = sc->root->d_sb;
+ mnt->mnt.mnt_root = dget(sc->root);
+ mnt->mnt_mountpoint = mnt->mnt.mnt_root;
+ mnt->mnt_parent = mnt;
+
+ lock_mount_hash();
+ list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
+ unlock_mount_hash();
+ return &mnt->mnt;
+}
+EXPORT_SYMBOL_GPL(vfs_kern_mount_sc);
+
+struct vfsmount *vfs_kern_mount(struct file_system_type *type,
+ int flags, const char *name, void *data)
+{
+ struct sb_config *sc;
+ struct vfsmount *mnt;
+ int ret;
+
+ if (!type)
+ return ERR_PTR(-EINVAL);
+
+ sc = __vfs_new_sb_config(type, NULL, flags, SB_CONFIG_FOR_NEW);
+ if (IS_ERR(sc))
+ return ERR_CAST(sc);
+
+ if (name) {
+ ret = -ENOMEM;
+ sc->device = kstrdup(name, GFP_KERNEL);
+ if (!sc->device)
+ goto err_sc;
+ }
+
+ ret = parse_monolithic_mount_data(sc, data);
+ if (ret < 0)
+ goto err_sc;
+
+ ret = vfs_get_tree(sc);
+ if (ret < 0)
+ goto err_sc;
+
+ mnt = vfs_kern_mount_sc(sc);
+ if (IS_ERR(mnt)) {
+ ret = PTR_ERR(mnt);
+ goto err_sc;
+ }
+
+ put_sb_config(sc);
+ return mnt;
+
+err_sc:
+ put_sb_config(sc);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(vfs_kern_mount);
+
+struct vfsmount *
+vfs_submount_sc(const struct dentry *mountpoint, struct sb_config *sc)
+{
+ /* Until it is worked out how to pass the user namespace
+ * through from the parent mount to the submount don't support
+ * unprivileged mounts with submounts.
+ */
+ if (mountpoint->d_sb->s_user_ns != &init_user_ns)
+ return ERR_PTR(-EPERM);
+
+ sc->ms_flags = MS_SUBMOUNT;
+ return vfs_kern_mount_sc(sc);
+}
+EXPORT_SYMBOL_GPL(vfs_submount_sc);
+
+struct vfsmount *
+vfs_submount(const struct dentry *mountpoint, struct file_system_type *type,
+ const char *name, void *data)
+{
+ /* Until it is worked out how to pass the user namespace
+ * through from the parent mount to the submount don't support
+ * unprivileged mounts with submounts.
+ */
+ if (mountpoint->d_sb->s_user_ns != &init_user_ns)
+ return ERR_PTR(-EPERM);
+
+ return vfs_kern_mount(type, MS_SUBMOUNT, name, data);
+}
+EXPORT_SYMBOL_GPL(vfs_submount);
+
/*
* Return true if path is reachable from root
*
@@ -3299,6 +3479,23 @@ struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
}
EXPORT_SYMBOL_GPL(kern_mount_data);
+struct vfsmount *kern_mount_data_sc(struct sb_config *sc)
+{
+ struct vfsmount *mnt;
+
+ sc->ms_flags = MS_KERNMOUNT;
+ mnt = vfs_kern_mount_sc(sc);
+ if (!IS_ERR(mnt)) {
+ /*
+ * it is a longterm mount, don't release mnt until
+ * we unmount before file sys is unregistered
+ */
+ real_mount(mnt)->mnt_ns = MNT_NS_INTERNAL;
+ }
+ return mnt;
+}
+EXPORT_SYMBOL_GPL(kern_mount_data_sc);
+
void kern_unmount(struct vfsmount *mnt)
{
/* release long term mount so mount point can be released */
diff --git a/fs/sb_config.c b/fs/sb_config.c
new file mode 100644
index 000000000000..4d9bfb982d41
--- /dev/null
+++ b/fs/sb_config.c
@@ -0,0 +1,512 @@
+/* Provide a way to create a superblock configuration context within the kernel
+ * that allows a superblock to be set up prior to mounting.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/sb_config.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/nsproxy.h>
+#include <linux/slab.h>
+#include <linux/magic.h>
+#include <linux/security.h>
+#include <linux/parser.h>
+#include <linux/mnt_namespace.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include <net/net_namespace.h>
+#include "mount.h"
+
+struct legacy_sb_config {
+ struct sb_config sc;
+ char *legacy_data; /* Data page for legacy filesystems */
+ char *secdata;
+ unsigned int data_usage;
+};
+
+static const struct sb_config_operations legacy_sb_config_ops;
+
+static const match_table_t common_set_mount_options = {
+ { MS_DIRSYNC, "dirsync" },
+ { MS_I_VERSION, "iversion" },
+ { MS_LAZYTIME, "lazytime" },
+ { MS_MANDLOCK, "mand" },
+ { MS_POSIXACL, "posixacl" },
+ { MS_RDONLY, "ro" },
+ { MS_REC, "rec" },
+ { MS_SYNCHRONOUS, "sync" },
+ { MS_VERBOSE, "verbose" },
+ { },
+};
+
+static const match_table_t common_clear_mount_options = {
+ { MS_LAZYTIME, "nolazytime" },
+ { MS_MANDLOCK, "nomand" },
+ { MS_RDONLY, "rw" },
+ { MS_SILENT, "silent" },
+ { MS_SYNCHRONOUS, "async" },
+ { },
+};
+
+static const match_table_t forbidden_mount_options = {
+ { MS_BIND, "bind" },
+ { MS_MOVE, "move" },
+ { MS_PRIVATE, "private" },
+ { MS_REMOUNT, "remount" },
+ { MS_SHARED, "shared" },
+ { MS_SLAVE, "slave" },
+ { MS_UNBINDABLE, "unbindable" },
+ { MS_NOATIME, "noatime" },
+ { MS_RELATIME, "relatime" },
+ { MS_RELATIME, "norelatime" },
+ { MS_STRICTATIME, "strictatime" },
+ { MS_STRICTATIME, "nostrictatime" },
+ { MS_NODIRATIME, "nodiratime" },
+ { MS_NODEV, "dev" },
+ { MS_NODEV, "nodev" },
+ { MS_NOEXEC, "exec" },
+ { MS_NOEXEC, "noexec" },
+ { MS_NOSUID, "suid" },
+ { MS_NOSUID, "nosuid" },
+ { },
+};
+
+/*
+ * Check for a common mount option.
+ */
+static int vfs_parse_ms_mount_option(struct sb_config *sc, char *data)
+{
+ substring_t args[MAX_OPT_ARGS];
+ unsigned int token;
+
+ token = match_token(data, common_set_mount_options, args);
+ if (token) {
+ sc->ms_flags |= token;
+ return 1;
+ }
+
+ token = match_token(data, common_clear_mount_options, args);
+ if (token) {
+ sc->ms_flags &= ~token;
+ return 1;
+ }
+
+ token = match_token(data, forbidden_mount_options, args);
+ if (token)
+ return invalf("VFS: Mount option, not superblock option");
+
+ return 0;
+}
+
+/**
+ * vfs_parse_mount_option - Add a single mount option to a superblock config
+ * @mc: The superblock configuration to modify
+ * @p: The option to apply.
+ *
+ * A single mount option in string form is applied to the superblock
+ * configuration being set up. Certain standard options (for example "ro") are
+ * translated into flag bits without going to the filesystem. The active
+ * security module is allowed to observe and poach options. Any other options
+ * are passed over to the filesystem to parse.
+ *
+ * This may be called multiple times for a context.
+ *
+ * Returns 0 on success and a negative error code on failure. In the event of
+ * failure, sc->error may have been set to a non-allocated string that gives
+ * more information.
+ */
+int vfs_parse_mount_option(struct sb_config *sc, char *p)
+{
+ int ret;
+
+ ret = vfs_parse_ms_mount_option(sc, p);
+ if (ret < 0)
+ return ret;
+ if (ret == 1)
+ return 0;
+
+ ret = security_sb_config_parse_option(sc, p);
+ if (ret < 0)
+ return ret;
+ if (ret == 1)
+ return 0;
+
+ if (sc->ops->parse_option)
+ return sc->ops->parse_option(sc, p);
+
+ return invalf("VFS: FS takes no options");
+}
+EXPORT_SYMBOL(vfs_parse_mount_option);
+
+/**
+ * generic_monolithic_mount_data - Parse key[=val][,key[=val]]* mount data
+ * @mc: The superblock configuration to fill in.
+ * @data: The data to parse
+ *
+ * Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
+ * called from the ->monolithic_mount_data() sb_config operation.
+ *
+ * Returns 0 on success or the error returned by the ->parse_option() sb_config
+ * operation on failure.
+ */
+int generic_monolithic_mount_data(struct sb_config *ctx, void *data)
+{
+ char *options = data, *p;
+ int ret;
+
+ if (!options)
+ return 0;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ if (*p) {
+ ret = vfs_parse_mount_option(ctx, p);
+ if (ret < 0)
+ return ret;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(generic_monolithic_mount_data);
+
+/**
+ * __vfs_new_sb_config - Create a superblock config.
+ * @fs_type: The filesystem type.
+ * @src_sb: A superblock from which this one derives (or NULL)
+ * @ms_flags: Superblock flags and op flags (such as MS_REMOUNT)
+ * @purpose: The purpose that this configuration shall be used for.
+ *
+ * Open a filesystem and create a mount context. The mount context is
+ * initialised with the supplied flags and, if a submount/automount from
+ * another superblock (@src_sb), may have parameters such as namespaces copied
+ * across from that superblock.
+ */
+struct sb_config *__vfs_new_sb_config(struct file_system_type *fs_type,
+ struct super_block *src_sb,
+ unsigned int ms_flags,
+ enum sb_config_purpose purpose)
+{
+ struct sb_config *sc;
+ size_t sc_size = fs_type->sb_config_size;
+ int ret;
+
+ BUG_ON(fs_type->init_sb_config && sc_size < sizeof(*sc));
+
+ if (!fs_type->init_sb_config)
+ sc_size = sizeof(struct legacy_sb_config);
+
+ sc = kzalloc(sc_size, GFP_KERNEL);
+ if (!sc)
+ return ERR_PTR(-ENOMEM);
+
+ sc->purpose = purpose;
+ sc->ms_flags = ms_flags;
+ sc->fs_type = get_filesystem(fs_type);
+ sc->net_ns = get_net(current->nsproxy->net_ns);
+ sc->user_ns = get_user_ns(current_user_ns());
+ sc->cred = get_current_cred();
+
+ /* TODO: Make all filesystems support this unconditionally */
+ if (sc->fs_type->init_sb_config) {
+ ret = sc->fs_type->init_sb_config(sc, src_sb);
+ if (ret < 0)
+ goto err_sc;
+ } else {
+ sc->ops = &legacy_sb_config_ops;
+ }
+
+ /* Do the security check last because ->init_sb_config may change the
+ * namespace subscriptions.
+ */
+ ret = security_sb_config_alloc(sc, src_sb);
+ if (ret < 0)
+ goto err_sc;
+
+ return sc;
+
+err_sc:
+ put_sb_config(sc);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(__vfs_new_sb_config);
+
+/**
+ * vfs_new_sb_config - Create a superblock config for a new mount.
+ * @fs_name: The name of the filesystem
+ *
+ * Open a filesystem and create a superblock config context for a new mount
+ * that will hold the mount options, device name, security details, etc.. Note
+ * that the caller should check the ->ops pointer in the returned context to
+ * determine whether the filesystem actually supports the superblock context
+ * itself.
+ */
+struct sb_config *vfs_new_sb_config(const char *fs_name)
+{
+ struct file_system_type *fs_type;
+ struct sb_config *sc;
+
+ fs_type = get_fs_type(fs_name);
+ if (!fs_type)
+ return ERR_PTR(-ENODEV);
+
+ sc = __vfs_new_sb_config(fs_type, NULL, 0, SB_CONFIG_FOR_NEW);
+ put_filesystem(fs_type);
+ return sc;
+}
+EXPORT_SYMBOL(vfs_new_sb_config);
+
+/**
+ * vfs_sb_reconfig - Create a superblock config for remount/reconfiguration
+ * @mnt: The mountpoint to open
+ * @ms_flags: Superblock flags and op flags (such as MS_REMOUNT)
+ *
+ * Open a mounted filesystem and create a mount context such that a remount can
+ * be effected.
+ */
+struct sb_config *vfs_sb_reconfig(struct vfsmount *mnt,
+ unsigned int ms_flags)
+{
+ return __vfs_new_sb_config(mnt->mnt_sb->s_type, mnt->mnt_sb,
+ ms_flags, SB_CONFIG_FOR_REMOUNT);
+}
+
+/**
+ * vfs_dup_sc_config: Duplicate a superblock configuration context.
+ * @src_sc: The context to copy.
+ */
+struct sb_config *vfs_dup_sb_config(struct sb_config *src_sc)
+{
+ struct sb_config *sc;
+ size_t sc_size;
+ int ret;
+
+ if (!src_sc->ops->dup)
+ return ERR_PTR(-ENOTSUPP);
+
+ sc_size = src_sc->fs_type->sb_config_size;
+ if (!src_sc->fs_type->init_sb_config)
+ sc_size = sizeof(struct legacy_sb_config);
+
+ sc = kmemdup(src_sc, src_sc->fs_type->sb_config_size, GFP_KERNEL);
+ if (!sc)
+ return ERR_PTR(-ENOMEM);
+
+ sc->device = NULL;
+ sc->security = NULL;
+ get_filesystem(sc->fs_type);
+ get_net(sc->net_ns);
+ get_user_ns(sc->user_ns);
+ get_cred(sc->cred);
+
+ /* Can't call put until we've called ->dup */
+ ret = sc->ops->dup(sc, src_sc);
+ if (ret < 0)
+ goto err_sc;
+
+ ret = security_sb_config_dup(sc, src_sc);
+ if (ret < 0)
+ goto err_sc;
+ return sc;
+
+err_sc:
+ put_sb_config(sc);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(vfs_dup_sb_config);
+
+/**
+ * put_sb_config - Dispose of a superblock configuration context.
+ * @sc: The context to dispose of.
+ */
+void put_sb_config(struct sb_config *sc)
+{
+ struct super_block *sb;
+
+ if (sc->root) {
+ sb = sc->root->d_sb;
+ dput(sc->root);
+ sc->root = NULL;
+ deactivate_super(sb);
+ }
+
+ if (sc->ops && sc->ops->free)
+ sc->ops->free(sc);
+
+ security_sb_config_free(sc);
+ if (sc->net_ns)
+ put_net(sc->net_ns);
+ put_user_ns(sc->user_ns);
+ if (sc->cred)
+ put_cred(sc->cred);
+ kfree(sc->subtype);
+ put_filesystem(sc->fs_type);
+ kfree(sc->device);
+ kfree(sc);
+}
+EXPORT_SYMBOL(put_sb_config);
+
+/*
+ * Free the config for a filesystem that doesn't support sb_config.
+ */
+static void legacy_sb_config_free(struct sb_config *sc)
+{
+ struct legacy_sb_config *cfg = container_of(sc, struct legacy_sb_config, sc);
+
+ free_secdata(cfg->secdata);
+ kfree(cfg->legacy_data);
+}
+
+/*
+ * Duplicate a legacy config.
+ */
+static int legacy_sb_config_dup(struct sb_config *sc, struct sb_config *src_sc)
+{
+ struct legacy_sb_config *cfg = container_of(sc, struct legacy_sb_config, sc);
+ struct legacy_sb_config *src_cfg = container_of(src_sc, struct legacy_sb_config, sc);
+
+ cfg->legacy_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!cfg->legacy_data)
+ return -ENOMEM;
+ memcpy(cfg->legacy_data, src_cfg->legacy_data, sizeof(PAGE_SIZE));
+ return 0;
+}
+
+/*
+ * Add an option to a legacy config. We build up a comma-separated list of
+ * options.
+ */
+static int legacy_parse_option(struct sb_config *sc, char *p)
+{
+ struct legacy_sb_config *cfg = container_of(sc, struct legacy_sb_config, sc);
+ unsigned int usage = cfg->data_usage;
+ size_t len = strlen(p);
+
+ if (len > PAGE_SIZE - 2 - usage)
+ return invalf("VFS: Insufficient data buffer space");
+ if (memchr(p, ',', len) != NULL)
+ return invalf("VFS: Options cannot contain commas");
+ if (!cfg->legacy_data) {
+ cfg->legacy_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!cfg->legacy_data)
+ return -ENOMEM;
+ }
+
+ cfg->legacy_data[usage++] = ',';
+ memcpy(cfg->legacy_data + usage, p, len);
+ usage += len;
+ cfg->legacy_data[usage] = '\0';
+ cfg->data_usage = usage;
+ return 0;
+}
+
+/*
+ * Add monolithic mount data.
+ */
+static int legacy_monolithic_mount_data(struct sb_config *sc, void *data)
+{
+ struct legacy_sb_config *cfg = container_of(sc, struct legacy_sb_config, sc);
+
+ if (cfg->data_usage != 0)
+ return invalf("VFS: Can't mix monolithic and individual options");
+ if (!data)
+ return 0;
+ if (!cfg->legacy_data) {
+ cfg->legacy_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!cfg->legacy_data)
+ return -ENOMEM;
+ }
+
+ memcpy(cfg->legacy_data, data, PAGE_SIZE);
+ cfg->data_usage = PAGE_SIZE;
+ return 0;
+}
+
+/*
+ * Use the legacy mount validation step to strip out and process security
+ * config options.
+ */
+static int legacy_validate(struct sb_config *sc)
+{
+ struct legacy_sb_config *cfg = container_of(sc, struct legacy_sb_config, sc);
+
+ if (!cfg->legacy_data || cfg->sc.fs_type->fs_flags & FS_BINARY_MOUNTDATA)
+ return 0;
+
+ cfg->secdata = alloc_secdata();
+ if (!cfg->secdata)
+ return -ENOMEM;
+
+ return security_sb_copy_data(cfg->legacy_data, cfg->secdata);
+}
+
+/*
+ * Determine the superblock subtype.
+ */
+static int legacy_set_subtype(struct sb_config *sc)
+{
+ const char *subtype = strchr(sc->fs_type->name, '.');
+
+ if (subtype) {
+ subtype++;
+ if (!subtype[0])
+ return -EINVAL;
+ } else {
+ subtype = "";
+ }
+
+ sc->subtype = kstrdup(subtype, GFP_KERNEL);
+ if (!sc->subtype)
+ return -ENOMEM;
+ return 0;
+}
+
+/*
+ * Get a mountable root with the legacy mount command.
+ */
+static int legacy_get_tree(struct sb_config *sc)
+{
+ struct legacy_sb_config *cfg = container_of(sc, struct legacy_sb_config, sc);
+ struct super_block *sb;
+ struct dentry *root;
+ int ret;
+
+ root = cfg->sc.fs_type->mount(cfg->sc.fs_type, cfg->sc.ms_flags,
+ cfg->sc.device, cfg->legacy_data);
+ if (IS_ERR(root))
+ return PTR_ERR(root);
+
+ sb = root->d_sb;
+ BUG_ON(!sb);
+
+ if ((cfg->sc.fs_type->fs_flags & FS_HAS_SUBTYPE) &&
+ !sc->subtype) {
+ ret = legacy_set_subtype(sc);
+ if (ret < 0)
+ goto err_sb;
+ }
+
+ cfg->sc.root = root;
+ return 0;
+
+err_sb:
+ dput(root);
+ deactivate_locked_super(sb);
+ return ret;
+}
+
+static const struct sb_config_operations legacy_sb_config_ops = {
+ .free = legacy_sb_config_free,
+ .dup = legacy_sb_config_dup,
+ .parse_option = legacy_parse_option,
+ .monolithic_mount_data = legacy_monolithic_mount_data,
+ .validate = legacy_validate,
+ .get_tree = legacy_get_tree,
+};
diff --git a/fs/super.c b/fs/super.c
index adb0c0de428c..e4b47d481679 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -34,6 +34,7 @@
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
+#include <linux/sb_config.h>
#include "internal.h"
@@ -805,10 +806,13 @@ struct super_block *user_get_super(dev_t dev)
* @flags: numeric part of options
* @data: the rest of options
* @force: whether or not to force the change
+ * @sc: the superblock config for filesystems that support it
+ * (NULL if called from emergency or umount)
*
* Alters the mount options of a mounted file system.
*/
-int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
+int do_remount_sb(struct super_block *sb, int flags, void *data, int force,
+ struct sb_config *sc)
{
int retval;
int remount_ro;
@@ -850,8 +854,14 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
}
}
- if (sb->s_op->remount_fs) {
- retval = sb->s_op->remount_fs(sb, &flags, data);
+ if (sb->s_op->remount_fs_sc ||
+ sb->s_op->remount_fs) {
+ if (sb->s_op->remount_fs_sc) {
+ retval = sb->s_op->remount_fs_sc(sb, sc);
+ flags = sc->ms_flags;
+ } else {
+ retval = sb->s_op->remount_fs(sb, &flags, data);
+ }
if (retval) {
if (!force)
goto cancel_readonly;
@@ -898,7 +908,7 @@ static void do_emergency_remount(struct work_struct *work)
/*
* What lock protects sb->s_flags??
*/
- do_remount_sb(sb, MS_RDONLY, NULL, 1);
+ do_remount_sb(sb, MS_RDONLY, NULL, 1, NULL);
}
up_write(&sb->s_umount);
spin_lock(&sb_lock);
@@ -1048,6 +1058,43 @@ struct dentry *mount_ns(struct file_system_type *fs_type,
EXPORT_SYMBOL(mount_ns);
+int mount_ns_sc(struct sb_config *sc,
+ int (*fill_super)(struct super_block *sb, struct sb_config *sc),
+ void *ns)
+{
+ struct super_block *sb;
+
+ /* Don't allow mounting unless the caller has CAP_SYS_ADMIN
+ * over the namespace.
+ */
+ if (!(sc->ms_flags & MS_KERNMOUNT) &&
+ !ns_capable(sc->user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ sb = sget_userns(sc->fs_type, ns_test_super, ns_set_super,
+ sc->ms_flags, sc->user_ns, ns);
+ if (IS_ERR(sb))
+ return PTR_ERR(sb);
+
+ if (!sb->s_root) {
+ int err;
+ err = fill_super(sb, sc);
+ if (err) {
+ deactivate_locked_super(sb);
+ return err;
+ }
+
+ sb->s_flags |= MS_ACTIVE;
+ }
+
+ if (!sc->root) {
+ sc->root = sb->s_root;
+ dget(sb->s_root);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(mount_ns_sc);
+
#ifdef CONFIG_BLOCK
static int set_bdev_super(struct super_block *s, void *data)
{
@@ -1196,7 +1243,7 @@ struct dentry *mount_single(struct file_system_type *fs_type,
}
s->s_flags |= MS_ACTIVE;
} else {
- do_remount_sb(s, flags, data, 0);
+ do_remount_sb(s, flags, data, 0, NULL);
}
return dget(s->s_root);
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index bc0c054894b9..1acb76f400c4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -54,6 +54,7 @@ struct workqueue_struct;
struct iov_iter;
struct fscrypt_info;
struct fscrypt_operations;
+struct sb_config;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -701,6 +702,11 @@ static inline void inode_unlock(struct inode *inode)
up_write(&inode->i_rwsem);
}
+static inline int inode_lock_killable(struct inode *inode)
+{
+ return down_write_killable(&inode->i_rwsem);
+}
+
static inline void inode_lock_shared(struct inode *inode)
{
down_read(&inode->i_rwsem);
@@ -1787,6 +1793,7 @@ struct super_operations {
int (*unfreeze_fs) (struct super_block *);
int (*statfs) (struct dentry *, struct kstatfs *);
int (*remount_fs) (struct super_block *, int *, char *);
+ int (*remount_fs_sc) (struct super_block *, struct sb_config *);
void (*umount_begin) (struct super_block *);
int (*show_options)(struct seq_file *, struct dentry *);
@@ -2021,8 +2028,10 @@ struct file_system_type {
#define FS_HAS_SUBTYPE 4
#define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
+ unsigned short sb_config_size; /* Size of superblock config context to allocate */
struct dentry *(*mount) (struct file_system_type *, int,
const char *, void *);
+ int (*init_sb_config)(struct sb_config *, struct super_block *);
void (*kill_sb) (struct super_block *);
struct module *owner;
struct file_system_type * next;
@@ -2040,6 +2049,10 @@ struct file_system_type {
#define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
+extern int mount_ns_sc(struct sb_config *mc,
+ int (*fill_super)(struct super_block *sb,
+ struct sb_config *sc),
+ void *ns);
extern struct dentry *mount_ns(struct file_system_type *fs_type,
int flags, void *data, void *ns, struct user_namespace *user_ns,
int (*fill_super)(struct super_block *, void *, int));
@@ -2106,6 +2119,7 @@ extern int register_filesystem(struct file_system_type *);
extern int unregister_filesystem(struct file_system_type *);
extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
#define kern_mount(type) kern_mount_data(type, NULL)
+extern struct vfsmount *kern_mount_data_sc(struct sb_config *);
extern void kern_unmount(struct vfsmount *mnt);
extern int may_umount_tree(struct vfsmount *);
extern int may_umount(struct vfsmount *);
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 8e0352af06b7..a5dca6abc4d5 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -20,6 +20,7 @@ struct super_block;
struct vfsmount;
struct dentry;
struct mnt_namespace;
+struct sb_config;
#define MNT_NOSUID 0x01
#define MNT_NODEV 0x02
@@ -90,9 +91,12 @@ struct file_system_type;
extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int flags, const char *name,
void *data);
+extern struct vfsmount *vfs_kern_mount_sc(struct sb_config *sc);
extern struct vfsmount *vfs_submount(const struct dentry *mountpoint,
struct file_system_type *type,
const char *name, void *data);
+extern struct vfsmount *vfs_submount_sc(const struct dentry *mountpoint,
+ struct sb_config *sc);
extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
extern void mark_mounts_for_expiry(struct list_head *mounts);
diff --git a/include/linux/sb_config.h b/include/linux/sb_config.h
index d2af7342a082..0da92dd99d60 100644
--- a/include/linux/sb_config.h
+++ b/include/linux/sb_config.h
@@ -69,4 +69,17 @@ struct sb_config_operations {
int (*get_tree)(struct sb_config *sc);
};
+extern struct sb_config *vfs_new_sb_config(const char *fs_name);
+extern struct sb_config *__vfs_new_sb_config(struct file_system_type *fs_type,
+ struct super_block *src_sb,
+ unsigned int ms_flags,
+ enum sb_config_purpose purpose);
+extern struct sb_config *vfs_sb_reconfig(struct vfsmount *mnt,
+ unsigned int ms_flags);
+extern struct sb_config *vfs_dup_sb_config(struct sb_config *src);
+extern int vfs_parse_mount_option(struct sb_config *sc, char *data);
+extern int generic_monolithic_mount_data(struct sb_config *sc, void *data);
+extern int vfs_get_tree(struct sb_config *sc);
+extern void put_sb_config(struct sb_config *sc);
+
#endif /* _LINUX_SB_CONFIG_H */
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 08/23] VFS: Add LSM hooks for superblock configuration context [ver #4] |
| Message-ID | <tJXUv-7yP-53@gated-at.bofh.it> |
| In reply to | #1647066 |
Add LSM hooks for use by the superblock configuration context code.
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/linux/lsm_hooks.h | 39 ++++++++++
include/linux/security.h | 28 +++++++
security/security.c | 25 +++++++
security/selinux/hooks.c | 169 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 261 insertions(+)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 080f34e66017..c2bbd9e92b0a 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -75,6 +75,34 @@
* should enable secure mode.
* @bprm contains the linux_binprm structure.
*
+ * Security hooks for mount using fd context.
+ *
+ * @sb_config_alloc:
+ * Allocate and attach a security structure to sc->security. This pointer
+ * is initialised to NULL by the caller.
+ * @sc indicates the new superblock configuration context.
+ * @src_sb indicates the source superblock of a submount.
+ * @sb_config_dup:
+ * Allocate and attach a security structure to sc->security. This pointer
+ * is initialised to NULL by the caller.
+ * @sc indicates the new superblock configuration context.
+ * @src_sc indicates the original superblock configuration context.
+ * @sb_config_free:
+ * Clean up a superblock configuration context.
+ * @sc indicates the superblock configuration context.
+ * @sb_config_parse_option:
+ * Userspace provided an option to configure a superblock. The LSM may
+ * reject it with an error and may use it for itself, in which case it
+ * should return 1; otherwise it should return 0 to pass it on to the
+ * filesystem.
+ * @sc indicates the superblock configuration context.
+ * @p indicates the option in "key[=val]" form.
+ * @sb_get_tree:
+ * Assign the security to a newly created superblock.
+ * @sc indicates the superblock configuration context.
+ * @sc->root indicates the root that will be mounted.
+ * @sc->root->d_sb points to the superblock.
+ *
* Security hooks for filesystem operations.
*
* @sb_alloc_security:
@@ -1372,6 +1400,12 @@ union security_list_options {
void (*bprm_committing_creds)(struct linux_binprm *bprm);
void (*bprm_committed_creds)(struct linux_binprm *bprm);
+ int (*sb_config_alloc)(struct sb_config *sc, struct super_block *src_sb);
+ int (*sb_config_dup)(struct sb_config *sc, struct sb_config *src_sc);
+ void (*sb_config_free)(struct sb_config *sc);
+ int (*sb_config_parse_option)(struct sb_config *sc, char *opt);
+ int (*sb_get_tree)(struct sb_config *sc);
+
int (*sb_alloc_security)(struct super_block *sb);
void (*sb_free_security)(struct super_block *sb);
int (*sb_copy_data)(char *orig, char *copy);
@@ -1683,6 +1717,11 @@ struct security_hook_heads {
struct list_head bprm_secureexec;
struct list_head bprm_committing_creds;
struct list_head bprm_committed_creds;
+ struct list_head sb_config_alloc;
+ struct list_head sb_config_dup;
+ struct list_head sb_config_free;
+ struct list_head sb_config_parse_option;
+ struct list_head sb_get_tree;
struct list_head sb_alloc_security;
struct list_head sb_free_security;
struct list_head sb_copy_data;
diff --git a/include/linux/security.h b/include/linux/security.h
index af675b576645..d1dfb6abd4f7 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -55,6 +55,7 @@ struct msg_queue;
struct xattr;
struct xfrm_sec_ctx;
struct mm_struct;
+struct sb_config;
/* If capable should audit the security request */
#define SECURITY_CAP_NOAUDIT 0
@@ -224,6 +225,11 @@ int security_bprm_check(struct linux_binprm *bprm);
void security_bprm_committing_creds(struct linux_binprm *bprm);
void security_bprm_committed_creds(struct linux_binprm *bprm);
int security_bprm_secureexec(struct linux_binprm *bprm);
+int security_sb_config_alloc(struct sb_config *sc, struct super_block *sb);
+int security_sb_config_dup(struct sb_config *sc, struct sb_config *src_sc);
+void security_sb_config_free(struct sb_config *sc);
+int security_sb_config_parse_option(struct sb_config *sc, char *opt);
+int security_sb_get_tree(struct sb_config *sc);
int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
int security_sb_copy_data(char *orig, char *copy);
@@ -520,6 +526,28 @@ static inline int security_bprm_secureexec(struct linux_binprm *bprm)
return cap_bprm_secureexec(bprm);
}
+static inline int security_sb_config_alloc(struct sb_config *sc,
+ struct super_block *src_sb)
+{
+ return 0;
+}
+static inline int security_sb_config_dup(struct sb_config *sc,
+ struct sb_config *src_sc)
+{
+ return 0;
+}
+static inline void security_sb_config_free(struct sb_config *sc)
+{
+}
+static inline int security_sb_config_parse_option(struct sb_config *sc, char *opt)
+{
+ return 0;
+}
+static inline int security_sb_get_tree(struct sb_config *sc)
+{
+ return 0;
+}
+
static inline int security_sb_alloc(struct super_block *sb)
{
return 0;
diff --git a/security/security.c b/security/security.c
index b9fea3999cf8..951f28487719 100644
--- a/security/security.c
+++ b/security/security.c
@@ -316,6 +316,31 @@ int security_bprm_secureexec(struct linux_binprm *bprm)
return call_int_hook(bprm_secureexec, 0, bprm);
}
+int security_sb_config_alloc(struct sb_config *sc, struct super_block *src_sb)
+{
+ return call_int_hook(sb_config_alloc, 0, sc, src_sb);
+}
+
+int security_sb_config_dup(struct sb_config *sc, struct sb_config *src_sc)
+{
+ return call_int_hook(sb_config_dup, 0, sc, src_sc);
+}
+
+void security_sb_config_free(struct sb_config *sc)
+{
+ call_void_hook(sb_config_free, sc);
+}
+
+int security_sb_config_parse_option(struct sb_config *sc, char *opt)
+{
+ return call_int_hook(sb_config_parse_option, 0, sc, opt);
+}
+
+int security_sb_get_tree(struct sb_config *sc)
+{
+ return call_int_hook(sb_get_tree, 0, sc);
+}
+
int security_sb_alloc(struct super_block *sb)
{
return call_int_hook(sb_alloc_security, 0, sb);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e67a526d1f30..420bfa955fb4 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -47,6 +47,7 @@
#include <linux/fdtable.h>
#include <linux/namei.h>
#include <linux/mount.h>
+#include <linux/sb_config.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/tty.h>
@@ -2826,6 +2827,168 @@ static int selinux_umount(struct vfsmount *mnt, int flags)
FILESYSTEM__UNMOUNT, NULL);
}
+/* fsopen mount context operations */
+
+static int selinux_sb_config_alloc(struct sb_config *sc,
+ struct super_block *src_sb)
+{
+ struct security_mnt_opts *opts;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+
+ sc->security = opts;
+ return 0;
+}
+
+static int selinux_sb_config_dup(struct sb_config *sc,
+ struct sb_config *src_sc)
+{
+ const struct security_mnt_opts *src = src_sc->security;
+ struct security_mnt_opts *opts;
+ int i, n;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+ sc->security = opts;
+
+ if (!src || !src->num_mnt_opts)
+ return 0;
+ n = opts->num_mnt_opts = src->num_mnt_opts;
+
+ if (src->mnt_opts) {
+ opts->mnt_opts = kcalloc(n, sizeof(char *), GFP_KERNEL);
+ if (!opts->mnt_opts)
+ return -ENOMEM;
+
+ for (i = 0; i < n; i++) {
+ if (src->mnt_opts[i]) {
+ opts->mnt_opts[i] = kstrdup(src->mnt_opts[i],
+ GFP_KERNEL);
+ if (!opts->mnt_opts[i])
+ return -ENOMEM;
+ }
+ }
+ }
+
+ if (src->mnt_opts_flags) {
+ opts->mnt_opts_flags = kmemdup(src->mnt_opts_flags,
+ n * sizeof(int), GFP_KERNEL);
+ if (!opts->mnt_opts_flags)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void selinux_sb_config_free(struct sb_config *sc)
+{
+ struct security_mnt_opts *opts = sc->security;
+
+ security_free_mnt_opts(opts);
+ sc->security = NULL;
+}
+
+static int selinux_sb_config_parse_option(struct sb_config *sc, char *opt)
+{
+ struct security_mnt_opts *opts = sc->security;
+ substring_t args[MAX_OPT_ARGS];
+ unsigned int have;
+ char *c, **oo;
+ int token, ctx, i, *of;
+
+ token = match_token(opt, tokens, args);
+ if (token == Opt_error)
+ return 0; /* Doesn't belong to us. */
+
+ have = 0;
+ for (i = 0; i < opts->num_mnt_opts; i++)
+ have |= 1 << opts->mnt_opts_flags[i];
+ if (have & (1 << token))
+ return invalf("SELinux: Duplicate mount options");
+
+ switch (token) {
+ case Opt_context:
+ if (have & (1 << Opt_defcontext))
+ goto incompatible;
+ ctx = CONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_fscontext:
+ ctx = FSCONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_rootcontext:
+ ctx = ROOTCONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_defcontext:
+ if (have & (1 << Opt_context))
+ goto incompatible;
+ ctx = DEFCONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_labelsupport:
+ return 1;
+
+ default:
+ return invalf("SELinux: Unknown mount option");
+ }
+
+copy_context_string:
+ if (opts->num_mnt_opts > 3)
+ return invalf("SELinux: Too many options");
+
+ of = krealloc(opts->mnt_opts_flags,
+ (opts->num_mnt_opts + 1) * sizeof(int), GFP_KERNEL);
+ if (!of)
+ return -ENOMEM;
+ of[opts->num_mnt_opts] = 0;
+ opts->mnt_opts_flags = of;
+
+ oo = krealloc(opts->mnt_opts,
+ (opts->num_mnt_opts + 1) * sizeof(char *), GFP_KERNEL);
+ if (!oo)
+ return -ENOMEM;
+ oo[opts->num_mnt_opts] = NULL;
+ opts->mnt_opts = oo;
+
+ c = match_strdup(&args[0]);
+ if (!c)
+ return -ENOMEM;
+ opts->mnt_opts[opts->num_mnt_opts] = c;
+ opts->mnt_opts_flags[opts->num_mnt_opts] = ctx;
+ opts->num_mnt_opts++;
+ return 1;
+
+incompatible:
+ return invalf("SELinux: Incompatible mount options");
+}
+
+static int selinux_sb_get_tree(struct sb_config *sc)
+{
+ const struct cred *cred = current_cred();
+ struct common_audit_data ad;
+ int rc;
+
+ rc = selinux_set_mnt_opts(sc->root->d_sb, sc->security, 0, NULL);
+ if (rc)
+ return rc;
+
+ /* Allow all mounts performed by the kernel */
+ if (sc->ms_flags & MS_KERNMOUNT)
+ return 0;
+
+ ad.type = LSM_AUDIT_DATA_DENTRY;
+ ad.u.dentry = sc->root;
+ rc = superblock_has_perm(cred, sc->root->d_sb, FILESYSTEM__MOUNT, &ad);
+ if (rc < 0)
+ errorf("SELinux: Mount of superblock not permitted");
+ return rc;
+}
+
/* inode security operations */
static int selinux_inode_alloc_security(struct inode *inode)
@@ -6154,6 +6317,12 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),
LSM_HOOK_INIT(bprm_secureexec, selinux_bprm_secureexec),
+ LSM_HOOK_INIT(sb_config_alloc, selinux_sb_config_alloc),
+ LSM_HOOK_INIT(sb_config_dup, selinux_sb_config_dup),
+ LSM_HOOK_INIT(sb_config_free, selinux_sb_config_free),
+ LSM_HOOK_INIT(sb_config_parse_option, selinux_sb_config_parse_option),
+ LSM_HOOK_INIT(sb_get_tree, selinux_sb_get_tree),
+
LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security),
LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
LSM_HOOK_INIT(sb_copy_data, selinux_sb_copy_data),
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 21/23] NFS: Add a small buffer in nfs_sb_config to avoid string dup [ver #4] |
| Message-ID | <tJXUv-7yP-35@gated-at.bofh.it> |
| In reply to | #1647066 |
Add a small buffer in nfs_sb_config to avoid string duplication when
parsing numbers. Also make the parsing function wrapper place the parsed
integer directly in the appropriate nfs_sb_config struct member.
Sigend-off-by: David Howells <dhowells@redhat.com>
---
fs/nfs/internal.h | 2 +
fs/nfs/mount.c | 83 +++++++++++++++++++----------------------------------
2 files changed, 32 insertions(+), 53 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index ed255241baa7..52242240933f 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -125,6 +125,8 @@ struct nfs_sb_config {
struct security_mnt_opts lsm_opts;
struct net *net;
+
+ char buf[32]; /* Parse buffer */
};
/* mount_clnt.c */
diff --git a/fs/nfs/mount.c b/fs/nfs/mount.c
index 8296f2f84dc7..e5593070422d 100644
--- a/fs/nfs/mount.c
+++ b/fs/nfs/mount.c
@@ -466,27 +466,22 @@ static int nfs_get_option_str(substring_t args[], char **option)
return !*option;
}
-static int nfs_get_option_ul(substring_t args[], unsigned long *option)
+static int nfs_get_option_ui(struct nfs_sb_config *cfg,
+ substring_t args[], unsigned int *option)
{
- int rc;
- char *string;
-
- string = match_strdup(args);
- if (string == NULL)
- return -ENOMEM;
- rc = kstrtoul(string, 10, option);
- kfree(string);
-
- return rc;
+ match_strlcpy(cfg->buf, args, sizeof(cfg->buf));
+ return kstrtouint(cfg->buf, 10, option);
}
-static int nfs_get_option_ul_bound(substring_t args[], unsigned long *option,
- unsigned long l_bound, unsigned long u_bound)
+static int nfs_get_option_ui_bound(struct nfs_sb_config *cfg,
+ substring_t args[], unsigned int *option,
+ unsigned int l_bound, unsigned u_bound)
{
int ret;
- ret = nfs_get_option_ul(args, option);
- if (ret != 0)
+ match_strlcpy(cfg->buf, args, sizeof(cfg->buf));
+ ret = kstrtouint(cfg->buf, 10, option);
+ if (ret < 0)
return ret;
if (*option < l_bound || *option > u_bound)
return -ERANGE;
@@ -499,7 +494,6 @@ static int nfs_get_option_ul_bound(substring_t args[], unsigned long *option,
static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
{
substring_t args[MAX_OPT_ARGS];
- unsigned long option;
char *string;
int rc, token;
@@ -507,7 +501,6 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
token = match_token(p, nfs_mount_option_tokens, args);
switch (token) {
-
/*
* boolean options: foo/nofoo
*/
@@ -603,86 +596,70 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
* options that take numeric values
*/
case Opt_port:
- if (nfs_get_option_ul(args, &option) ||
- option > USHRT_MAX)
+ if (nfs_get_option_ui_bound(cfg, args, &cfg->nfs_server.port,
+ 0, USHRT_MAX))
goto out_invalid_value;
- cfg->nfs_server.port = option;
break;
case Opt_rsize:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->rsize))
goto out_invalid_value;
- cfg->rsize = option;
break;
case Opt_wsize:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->wsize))
goto out_invalid_value;
- cfg->wsize = option;
break;
case Opt_bsize:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->bsize))
goto out_invalid_value;
- cfg->bsize = option;
break;
case Opt_timeo:
- if (nfs_get_option_ul_bound(args, &option, 1, INT_MAX))
+ if (nfs_get_option_ui_bound(cfg, args, &cfg->timeo, 1, INT_MAX))
goto out_invalid_value;
- cfg->timeo = option;
break;
case Opt_retrans:
- if (nfs_get_option_ul_bound(args, &option, 0, INT_MAX))
+ if (nfs_get_option_ui_bound(cfg, args, &cfg->retrans, 0, INT_MAX))
goto out_invalid_value;
- cfg->retrans = option;
break;
case Opt_acregmin:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->acregmin))
goto out_invalid_value;
- cfg->acregmin = option;
break;
case Opt_acregmax:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->acregmax))
goto out_invalid_value;
- cfg->acregmax = option;
break;
case Opt_acdirmin:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->acdirmin))
goto out_invalid_value;
- cfg->acdirmin = option;
break;
case Opt_acdirmax:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->acdirmax))
goto out_invalid_value;
- cfg->acdirmax = option;
break;
case Opt_actimeo:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->acdirmax))
goto out_invalid_value;
cfg->acregmin = cfg->acregmax =
- cfg->acdirmin = cfg->acdirmax = option;
+ cfg->acdirmin = cfg->acdirmax;
break;
case Opt_namelen:
- if (nfs_get_option_ul(args, &option))
+ if (nfs_get_option_ui(cfg, args, &cfg->namlen))
goto out_invalid_value;
- cfg->namlen = option;
break;
case Opt_mountport:
- if (nfs_get_option_ul(args, &option) ||
- option > USHRT_MAX)
+ if (nfs_get_option_ui_bound(cfg, args, &cfg->mount_server.port,
+ 0, USHRT_MAX))
goto out_invalid_value;
- cfg->mount_server.port = option;
break;
case Opt_mountvers:
- if (nfs_get_option_ul(args, &option) ||
- option < NFS_MNT_VERSION ||
- option > NFS_MNT3_VERSION)
+ if (nfs_get_option_ui_bound(cfg, args, &cfg->mount_server.version,
+ NFS_MNT_VERSION, NFS_MNT3_VERSION))
goto out_invalid_value;
- cfg->mount_server.version = option;
break;
case Opt_minorversion:
- if (nfs_get_option_ul(args, &option))
- goto out_invalid_value;
- if (option > NFS4_MAX_MINOR_VERSION)
+ if (nfs_get_option_ui_bound(cfg, args, &cfg->minorversion,
+ 0, NFS4_MAX_MINOR_VERSION))
goto out_invalid_value;
- cfg->minorversion = option;
break;
/*
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 01/23] Provide a function to create a NUL-terminated string from unterminated data [ver #4] |
| Message-ID | <tJXUv-7yP-61@gated-at.bofh.it> |
| In reply to | #1647066 |
Provide a function, kmemdup_nul(), that will create a NUL-terminated string
from an unterminated character array where the length is known in advance.
This is better than kstrndup() in situations where we already know the
string length as the strnlen() in kstrndup() is superfluous.
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/linux/string.h | 1 +
mm/util.c | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/include/linux/string.h b/include/linux/string.h
index 537918f8a98e..3dd944cfe171 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -131,6 +131,7 @@ extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
extern const char *kstrdup_const(const char *s, gfp_t gfp);
extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
+extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
extern void argv_free(char **argv);
diff --git a/mm/util.c b/mm/util.c
index 464df3489903..cc9f0a2810bd 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -83,6 +83,8 @@ EXPORT_SYMBOL(kstrdup_const);
* @s: the string to duplicate
* @max: read at most @max chars from @s
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
+ *
+ * Note: Use kmemdup_nul() instead if the size is known exactly.
*/
char *kstrndup(const char *s, size_t max, gfp_t gfp)
{
@@ -121,6 +123,28 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp)
EXPORT_SYMBOL(kmemdup);
/**
+ * kmemdup_nul - Create a NUL-terminated string from unterminated data
+ * @s: The data to stringify
+ * @len: The size of the data
+ * @gfp: the GFP mask used in the kmalloc() call when allocating memory
+ */
+char *kmemdup_nul(const char *s, size_t len, gfp_t gfp)
+{
+ char *buf;
+
+ if (!s)
+ return NULL;
+
+ buf = kmalloc_track_caller(len + 1, gfp);
+ if (buf) {
+ memcpy(buf, s, len);
+ buf[len] = '\0';
+ }
+ return buf;
+}
+EXPORT_SYMBOL(kmemdup_nul);
+
+/**
* memdup_user - duplicate memory region from user space
*
* @src: source address in user space
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 11/23] VFS: Implement fsopen() to prepare for a mount [ver #4] |
| Message-ID | <tJXUv-7yP-55@gated-at.bofh.it> |
| In reply to | #1647066 |
Provide an fsopen() system call that starts the process of preparing to
mount, using an fd as a context handle. fsopen() is given the name of the
filesystem that will be used:
int mfd = fsopen(const char *fsname, int reserved,
int open_flags);
where reserved should be -1 for the moment (it will be used to pass the
namespace information in future) and open_flags can be 0 or O_CLOEXEC.
For example:
mfd = fsopen("ext4", -1, O_CLOEXEC);
write(mfd, "s /dev/sdb1"); // note I'm ignoring write's length arg
write(mfd, "o noatime");
write(mfd, "o acl");
write(mfd, "o user_attr");
write(mfd, "o iversion");
write(mfd, "o ");
write(mfd, "r /my/container"); // root inside the fs
write(mfd, "x create"); // create the superblock
fsmount(mfd, container_fd, "/mnt", AT_NO_FOLLOW);
mfd = fsopen("afs", -1);
write(mfd, "s %grand.central.org:root.cell");
write(mfd, "o cell=grand.central.org");
write(mfd, "r /");
write(mfd, "x create");
fsmount(mfd, AT_FDCWD, "/mnt", 0);
If an error is reported at any step, an error message may be available to be
read() back (ENODATA will be reported if there isn't an error available) in
the form:
"e <subsys>:<problem>"
"e SELinux:Mount on mountpoint not permitted"
Once fsmount() has been called, further write() calls will incur EBUSY,
even if the fsmount() fails. read() is still possible to retrieve error
information.
The fsopen() syscall creates a mount context and hangs it of the fd that it
returns.
Netlink is not used because it is optional.
Signed-off-by: David Howells <dhowells@redhat.com>
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/Makefile | 2
fs/fsopen.c | 267 ++++++++++++++++++++++++++++++++
include/linux/sb_config.h | 2
include/linux/syscalls.h | 1
include/uapi/linux/magic.h | 1
kernel/sys_ni.c | 3
8 files changed, 277 insertions(+), 1 deletion(-)
create mode 100644 fs/fsopen.c
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 448ac2161112..9bf8d4c62f85 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -391,3 +391,4 @@
382 i386 pkey_free sys_pkey_free
383 i386 statx sys_statx
384 i386 arch_prctl sys_arch_prctl compat_sys_arch_prctl
+385 i386 fsopen sys_fsopen
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 5aef183e2f85..9b198c5fc412 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -339,6 +339,7 @@
330 common pkey_alloc sys_pkey_alloc
331 common pkey_free sys_pkey_free
332 common statx sys_statx
+333 common fsopen sys_fsopen
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/Makefile b/fs/Makefile
index 8f5142525866..b8fcf48b0400 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -12,7 +12,7 @@ obj-y := open.o read_write.o file_table.o super.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o splice.o sync.o utimes.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
- sb_config.o
+ sb_config.o fsopen.o
ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o block_dev.o direct-io.o mpage.o
diff --git a/fs/fsopen.c b/fs/fsopen.c
new file mode 100644
index 000000000000..cbede77158ba
--- /dev/null
+++ b/fs/fsopen.c
@@ -0,0 +1,267 @@
+/* Filesystem access-by-fd.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/sb_config.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/file.h>
+#include <linux/magic.h>
+#include <linux/syscalls.h>
+
+static struct vfsmount *fs_fs_mnt __read_mostly;
+
+static int fs_fs_release(struct inode *inode, struct file *file)
+{
+ struct sb_config *sc = file->private_data;
+
+ file->private_data = NULL;
+
+ put_sb_config(sc);
+ return 0;
+}
+
+/*
+ * Userspace writes configuration data and commands to the fd and we parse it
+ * here. For the moment, we assume a single option or command per write. Each
+ * line written is of the form
+ *
+ * <option_type><space><stuff...>
+ *
+ * d /dev/sda1 -- Device name
+ * o noatime -- Option without value
+ * o cell=grand.central.org -- Option with value
+ * r / -- Dir within device to mount
+ * x create -- Create a superblock
+ */
+static ssize_t fs_fs_write(struct file *file,
+ const char __user *_buf, size_t len, loff_t *pos)
+{
+ struct sb_config *sc = file->private_data;
+ struct inode *inode = file_inode(file);
+ char opt[2], *data;
+ ssize_t ret;
+
+ if (len < 3 || len > 4095)
+ return -EINVAL;
+
+ if (copy_from_user(opt, _buf, 2) != 0)
+ return -EFAULT;
+ switch (opt[0]) {
+ case 's':
+ case 'o':
+ case 'x':
+ break;
+ default:
+ goto err_bad_cmd;
+ }
+ if (opt[1] != ' ')
+ goto err_bad_cmd;
+
+ data = memdup_user_nul(_buf + 2, len - 2);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ /* From this point onwards we need to lock the fd against someone
+ * trying to mount it.
+ */
+ ret = inode_lock_killable(inode);
+ if (ret < 0)
+ goto err_free;
+
+ ret = -EINVAL;
+ switch (opt[0]) {
+ case 's':
+ if (sc->device)
+ goto err_unlock;
+ sc->device = data;
+ data = NULL;
+ break;
+
+ case 'o':
+ ret = vfs_parse_mount_option(sc, data);
+ if (ret < 0)
+ goto err_unlock;
+ break;
+
+ case 'x':
+ if (strcmp(data, "create") == 0) {
+ ret = vfs_get_tree(sc);
+ } else {
+ ret = invalf("VFS: Invalid command");
+ }
+ if (ret < 0)
+ goto err_unlock;
+ break;
+
+ default:
+ goto err_unlock;
+ }
+
+ ret = len;
+err_unlock:
+ inode_unlock(inode);
+err_free:
+ kfree(data);
+ return ret;
+err_bad_cmd:
+ return invalf("VFS: Unsupported write spec");
+}
+
+const struct file_operations fs_fs_fops = {
+ .write = fs_fs_write,
+ .release = fs_fs_release,
+ .llseek = no_llseek,
+};
+
+/*
+ * Indicate the name we want to display the filesystem file as.
+ */
+static char *fs_fs_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+ return dynamic_dname(dentry, buffer, buflen, "fs:[%lu]",
+ d_inode(dentry)->i_ino);
+}
+
+static const struct dentry_operations fs_fs_dentry_operations = {
+ .d_dname = fs_fs_dname,
+};
+
+/*
+ * Create a file that can be used to configure a new mount.
+ */
+static struct file *create_fs_file(struct sb_config *sc)
+{
+ struct inode *inode;
+ struct file *f;
+ struct path path;
+ int ret;
+
+ inode = alloc_anon_inode(fs_fs_mnt->mnt_sb);
+ if (!inode)
+ return ERR_PTR(-ENFILE);
+ inode->i_fop = &fs_fs_fops;
+
+ ret = -ENOMEM;
+ path.dentry = d_alloc_pseudo(fs_fs_mnt->mnt_sb, &empty_name);
+ if (!path.dentry)
+ goto err_inode;
+ path.mnt = mntget(fs_fs_mnt);
+
+ d_instantiate(path.dentry, inode);
+
+ f = alloc_file(&path, FMODE_READ | FMODE_WRITE, &fs_fs_fops);
+ if (IS_ERR(f)) {
+ ret = PTR_ERR(f);
+ goto err_file;
+ }
+
+ f->private_data = sc;
+ return f;
+
+err_file:
+ path_put(&path);
+ return ERR_PTR(ret);
+
+err_inode:
+ iput(inode);
+ return ERR_PTR(ret);
+}
+
+ const struct super_operations fs_fs_ops = {
+ .drop_inode = generic_delete_inode,
+ .destroy_inode = free_inode_nonrcu,
+ .statfs = simple_statfs,
+};
+
+static struct dentry *fs_fs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return mount_pseudo(fs_type, "fs_fs:", &fs_fs_ops,
+ &fs_fs_dentry_operations, FS_FS_MAGIC);
+}
+
+static struct file_system_type fs_fs_type = {
+ .name = "fs_fs",
+ .mount = fs_fs_mount,
+ .kill_sb = kill_anon_super,
+};
+
+static int __init init_fs_fs(void)
+{
+ int ret;
+
+ ret = register_filesystem(&fs_fs_type);
+ if (ret < 0)
+ panic("Cannot register fs_fs\n");
+
+ fs_fs_mnt = kern_mount(&fs_fs_type);
+ if (IS_ERR(fs_fs_mnt))
+ panic("Cannot mount fs_fs: %ld\n", PTR_ERR(fs_fs_mnt));
+ return 0;
+}
+
+fs_initcall(init_fs_fs);
+
+/*
+ * Open a filesystem by name so that it can be configured for mounting.
+ *
+ * We are allowed to specify a container in which the filesystem will be
+ * opened, thereby indicating which namespaces will be used (notably, which
+ * network namespace will be used for network filesystems).
+ */
+SYSCALL_DEFINE3(fsopen, const char __user *, _fs_name, int, reserved,
+ unsigned int, flags)
+{
+ struct sb_config *sc;
+ struct file *file;
+ const char *fs_name;
+ int fd, ret;
+
+ if (flags & ~O_CLOEXEC || reserved != -1)
+ return -EINVAL;
+
+ fs_name = strndup_user(_fs_name, PAGE_SIZE);
+ if (IS_ERR(fs_name))
+ return PTR_ERR(fs_name);
+
+ sc = vfs_new_sb_config(fs_name);
+ kfree(fs_name);
+ if (IS_ERR(sc))
+ return PTR_ERR(sc);
+
+ ret = -ENOTSUPP;
+ if (!sc->ops)
+ goto err_sc;
+
+ file = create_fs_file(sc);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto err_sc;
+ }
+
+ ret = get_unused_fd_flags(flags & O_CLOEXEC);
+ if (ret < 0)
+ goto err_file;
+
+ fd = ret;
+ fd_install(fd, file);
+ return fd;
+
+err_file:
+ fput(file);
+ return ret;
+
+err_sc:
+ put_sb_config(sc);
+ return ret;
+}
diff --git a/include/linux/sb_config.h b/include/linux/sb_config.h
index 0da92dd99d60..144258d82fa1 100644
--- a/include/linux/sb_config.h
+++ b/include/linux/sb_config.h
@@ -82,4 +82,6 @@ extern int generic_monolithic_mount_data(struct sb_config *sc, void *data);
extern int vfs_get_tree(struct sb_config *sc);
extern void put_sb_config(struct sb_config *sc);
+extern const struct file_operations fs_fs_fops;
+
#endif /* _LINUX_SB_CONFIG_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 980c3c9b06f8..91ec8802ad5d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -905,5 +905,6 @@ asmlinkage long sys_pkey_alloc(unsigned long flags, unsigned long init_val);
asmlinkage long sys_pkey_free(int pkey);
asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
unsigned mask, struct statx __user *buffer);
+asmlinkage long sys_fsopen(const char *fs_name, int containerfd, unsigned int flags);
#endif
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index e230af2e6855..88ae83492f7c 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -84,5 +84,6 @@
#define UDF_SUPER_MAGIC 0x15013346
#define BALLOON_KVM_MAGIC 0x13661366
#define ZSMALLOC_MAGIC 0x58295829
+#define FS_FS_MAGIC 0x66736673
#endif /* __LINUX_MAGIC_H__ */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 8acef8576ce9..de1dc63e7e47 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -258,3 +258,6 @@ cond_syscall(sys_membarrier);
cond_syscall(sys_pkey_mprotect);
cond_syscall(sys_pkey_alloc);
cond_syscall(sys_pkey_free);
+
+/* fd-based mount */
+cond_syscall(sys_fsopen);
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 05/23] VFS: Provide empty name qstr [ver #4] |
| Message-ID | <tJXUw-7yP-63@gated-at.bofh.it> |
| In reply to | #1647066 |
Provide an empty name (ie. "") qstr for general use.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/dcache.c | 8 ++++++--
fs/gfs2/dir.c | 3 +--
fs/namei.c | 3 +--
fs/nsfs.c | 3 +--
fs/pipe.c | 3 +--
include/linux/dcache.h | 5 +++++
6 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index cddf39777835..d3da2a3ffd73 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -90,6 +90,11 @@ EXPORT_SYMBOL(rename_lock);
static struct kmem_cache *dentry_cache __read_mostly;
+const struct qstr empty_name = QSTR_INIT("", 0);
+EXPORT_SYMBOL(empty_name);
+const struct qstr slash_name = QSTR_INIT("/", 1);
+EXPORT_SYMBOL(slash_name);
+
/*
* This is the single most critical data structure when it comes
* to the dcache: the hashtable for lookups. Somebody should try
@@ -1580,8 +1585,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
*/
dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
if (unlikely(!name)) {
- static const struct qstr anon = QSTR_INIT("/", 1);
- name = &anon;
+ name = &slash_name;
dname = dentry->d_iname;
} else if (name->len > DNAME_INLINE_LEN-1) {
size_t size = offsetof(struct external_name, name[1]);
diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 79113219be5f..a5dfff6a033e 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -872,7 +872,6 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
struct buffer_head *bh;
struct gfs2_leaf *leaf;
struct gfs2_dirent *dent;
- struct qstr name = { .name = "" };
struct timespec tv = current_time(inode);
error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
@@ -896,7 +895,7 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
leaf->lf_sec = cpu_to_be64(tv.tv_sec);
memset(leaf->lf_reserved2, 0, sizeof(leaf->lf_reserved2));
dent = (struct gfs2_dirent *)(leaf+1);
- gfs2_qstr2dirent(&name, bh->b_size - sizeof(struct gfs2_leaf), dent);
+ gfs2_qstr2dirent(&empty_name, bh->b_size - sizeof(struct gfs2_leaf), dent);
*pbh = bh;
return leaf;
}
diff --git a/fs/namei.c b/fs/namei.c
index 6571a5f5112e..0d35760fee00 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3400,7 +3400,6 @@ static int do_last(struct nameidata *nd,
struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
{
- static const struct qstr name = QSTR_INIT("/", 1);
struct dentry *child = NULL;
struct inode *dir = dentry->d_inode;
struct inode *inode;
@@ -3414,7 +3413,7 @@ struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
if (!dir->i_op->tmpfile)
goto out_err;
error = -ENOMEM;
- child = d_alloc(dentry, &name);
+ child = d_alloc(dentry, &slash_name);
if (unlikely(!child))
goto out_err;
error = dir->i_op->tmpfile(dir, child, mode);
diff --git a/fs/nsfs.c b/fs/nsfs.c
index f3db56e83dd2..08127a2b8559 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -53,7 +53,6 @@ static void nsfs_evict(struct inode *inode)
static void *__ns_get_path(struct path *path, struct ns_common *ns)
{
struct vfsmount *mnt = nsfs_mnt;
- struct qstr qname = { .name = "", };
struct dentry *dentry;
struct inode *inode;
unsigned long d;
@@ -85,7 +84,7 @@ static void *__ns_get_path(struct path *path, struct ns_common *ns)
inode->i_fop = &ns_file_operations;
inode->i_private = ns;
- dentry = d_alloc_pseudo(mnt->mnt_sb, &qname);
+ dentry = d_alloc_pseudo(mnt->mnt_sb, &empty_name);
if (!dentry) {
iput(inode);
return ERR_PTR(-ENOMEM);
diff --git a/fs/pipe.c b/fs/pipe.c
index 73b84baf58f8..97e5be897753 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -739,13 +739,12 @@ int create_pipe_files(struct file **res, int flags)
struct inode *inode = get_pipe_inode();
struct file *f;
struct path path;
- static struct qstr name = { .name = "" };
if (!inode)
return -ENFILE;
err = -ENOMEM;
- path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name);
+ path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &empty_name);
if (!path.dentry)
goto err_inode;
path.mnt = mntget(pipe_mnt);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index d2e38dc6172c..3f65a4fa72ed 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -55,6 +55,11 @@ struct qstr {
#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
+extern const char empty_string[];
+extern const struct qstr empty_name;
+extern const char slash_string[];
+extern const struct qstr slash_name;
+
struct dentry_stat_t {
long nr_dentry;
long nr_unused;
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 22/23] NFS: Do some tidying of the parsing code [ver #4] |
| Message-ID | <tJXUw-7yP-73@gated-at.bofh.it> |
| In reply to | #1647066 |
Do some tidying of the parsing code, including:
(*) Returning 0/error rather than true/false.
(*) Putting the nfs_sb_config pointer first in some arg lists.
(*) Unwrap some lines that will now fit on one line.
(*) Provide unioned sockaddr/sockaddr_storage fields to avoid casts.
(*) nfs_parse_devname() can paste its return values directly into the
nfs_sb_config struct as that's where the caller puts them.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/nfs/internal.h | 16 +++++--
fs/nfs/mount.c | 128 +++++++++++++++++++++++------------------------------
fs/nfs/super.c | 2 -
3 files changed, 67 insertions(+), 79 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 52242240933f..79e77ff2061c 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -86,11 +86,11 @@ struct nfs_client_initdata {
* In-kernel mount arguments
*/
struct nfs_sb_config {
- int flags;
+ unsigned int flags; /* NFS{,4}_MOUNT_* flags */
unsigned int rsize, wsize;
unsigned int timeo, retrans;
- unsigned int acregmin, acregmax,
- acdirmin, acdirmax;
+ unsigned int acregmin, acregmax;
+ unsigned int acdirmin, acdirmax;
unsigned int namlen;
unsigned int options;
unsigned int bsize;
@@ -106,7 +106,10 @@ struct nfs_sb_config {
bool sloppy;
struct {
- struct sockaddr_storage address;
+ union {
+ struct sockaddr address;
+ struct sockaddr_storage _address;
+ };
size_t addrlen;
char *hostname;
u32 version;
@@ -115,7 +118,10 @@ struct nfs_sb_config {
} mount_server;
struct {
- struct sockaddr_storage address;
+ union {
+ struct sockaddr address;
+ struct sockaddr_storage _address;
+ };
size_t addrlen;
char *hostname;
char *export_path;
diff --git a/fs/nfs/mount.c b/fs/nfs/mount.c
index e5593070422d..025525c8eb90 100644
--- a/fs/nfs/mount.c
+++ b/fs/nfs/mount.c
@@ -341,8 +341,9 @@ static void nfs_set_mount_transport_protocol(struct nfs_sb_config *cfg)
* Add 'flavor' to 'auth_info' if not already present.
* Returns true if 'flavor' ends up in the list, false otherwise
*/
-static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
- rpc_authflavor_t flavor)
+static int nfs_auth_info_add(struct nfs_sb_config *cfg,
+ struct nfs_auth_info *auth_info,
+ rpc_authflavor_t flavor)
{
unsigned int i;
unsigned int max_flavor_len = ARRAY_SIZE(auth_info->flavors);
@@ -350,26 +351,27 @@ static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
/* make sure this flavor isn't already in the list */
for (i = 0; i < auth_info->flavor_len; i++) {
if (flavor == auth_info->flavors[i])
- return true;
+ return 0;
}
if (auth_info->flavor_len + 1 >= max_flavor_len) {
dfprintk(MOUNT, "NFS: too many sec= flavors\n");
- return false;
+ return -EINVAL;
}
auth_info->flavors[auth_info->flavor_len++] = flavor;
- return true;
+ return 0;
}
/*
* Parse the value of the 'sec=' option.
*/
-static int nfs_parse_security_flavors(char *value, struct nfs_sb_config *cfg)
+static int nfs_parse_security_flavors(struct nfs_sb_config *cfg, char *value)
{
substring_t args[MAX_OPT_ARGS];
rpc_authflavor_t pseudoflavor;
char *p;
+ int ret;
dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
@@ -411,19 +413,20 @@ static int nfs_parse_security_flavors(char *value, struct nfs_sb_config *cfg)
default:
dfprintk(MOUNT,
"NFS: sec= option '%s' not recognized\n", p);
- return 0;
+ return -EINVAL;
}
- if (!nfs_auth_info_add(&cfg->auth_info, pseudoflavor))
- return 0;
+ ret = nfs_auth_info_add(cfg, &cfg->auth_info, pseudoflavor);
+ if (ret < 0)
+ return ret;
}
- return 1;
+ return 0;
}
-static int nfs_parse_version_string(char *string,
- struct nfs_sb_config *cfg,
- substring_t *args)
+static int nfs_parse_version_string(struct nfs_sb_config *cfg,
+ char *string,
+ substring_t *args)
{
cfg->flags &= ~NFS_MOUNT_VER3;
switch (match_token(string, nfs_vers_tokens, args)) {
@@ -454,9 +457,10 @@ static int nfs_parse_version_string(char *string,
cfg->minorversion = 2;
break;
default:
- return 0;
+ dfprintk(MOUNT, "NFS: Unsupported NFS version\n");
+ return -EINVAL;
}
- return 1;
+ return 0;
}
static int nfs_get_option_str(substring_t args[], char **option)
@@ -495,7 +499,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
{
substring_t args[MAX_OPT_ARGS];
char *string;
- int rc, token;
+ int ret, token;
dfprintk(MOUNT, "NFS: parsing nfs mount option '%s'\n", p);
@@ -530,13 +534,11 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
break;
case Opt_lock:
cfg->flags &= ~NFS_MOUNT_NONLM;
- cfg->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
- NFS_MOUNT_LOCAL_FCNTL);
+ cfg->flags &= ~(NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
break;
case Opt_nolock:
cfg->flags |= NFS_MOUNT_NONLM;
- cfg->flags |= (NFS_MOUNT_LOCAL_FLOCK |
- NFS_MOUNT_LOCAL_FCNTL);
+ cfg->flags |= (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
break;
case Opt_udp:
cfg->flags &= ~NFS_MOUNT_TCP;
@@ -669,29 +671,25 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
- rc = nfs_parse_version_string(string, cfg, args);
+ ret = nfs_parse_version_string(cfg, string, args);
kfree(string);
- if (!rc)
- goto out_invalid_value;
+ if (ret < 0)
+ return ret;
break;
case Opt_sec:
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
- rc = nfs_parse_security_flavors(string, cfg);
+ ret = nfs_parse_security_flavors(cfg, string);
kfree(string);
- if (!rc) {
- dfprintk(MOUNT, "NFS: unrecognized "
- "security flavor\n");
- return -EINVAL;
- }
+ if (ret < 0)
+ return ret;
break;
case Opt_proto:
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
- token = match_token(string,
- nfs_xprt_protocol_tokens, args);
+ token = match_token(string, nfs_xprt_protocol_tokens, args);
cfg->protofamily = AF_INET;
switch (token) {
@@ -716,9 +714,8 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
xprt_load_transport(string);
break;
default:
- dfprintk(MOUNT, "NFS: unrecognized "
- "transport protocol\n");
kfree(string);
+ dfprintk(MOUNT, "NFS: unrecognized transport protocol\n");
return -EINVAL;
}
kfree(string);
@@ -727,8 +724,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
- token = match_token(string,
- nfs_xprt_protocol_tokens, args);
+ token = match_token(string, nfs_xprt_protocol_tokens, args);
kfree(string);
cfg->mountfamily = AF_INET;
@@ -745,8 +741,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
break;
case Opt_xprt_rdma: /* not used for side protocols */
default:
- dfprintk(MOUNT, "NFS: unrecognized "
- "transport protocol\n");
+ dfprintk(MOUNT, "NFS: unrecognized transport protocol\n");
return -EINVAL;
}
break;
@@ -756,9 +751,8 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
goto out_nomem;
cfg->nfs_server.addrlen =
rpc_pton(cfg->net, string, strlen(string),
- (struct sockaddr *)
&cfg->nfs_server.address,
- sizeof(cfg->nfs_server.address));
+ sizeof(cfg->nfs_server._address));
kfree(string);
if (cfg->nfs_server.addrlen == 0)
goto out_invalid_address;
@@ -768,8 +762,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
goto out_nomem;
break;
case Opt_mounthost:
- if (nfs_get_option_str(args,
- &cfg->mount_server.hostname))
+ if (nfs_get_option_str(args, &cfg->mount_server.hostname))
goto out_nomem;
break;
case Opt_mountaddr:
@@ -778,9 +771,8 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
goto out_nomem;
cfg->mount_server.addrlen =
rpc_pton(cfg->net, string, strlen(string),
- (struct sockaddr *)
&cfg->mount_server.address,
- sizeof(cfg->mount_server.address));
+ sizeof(cfg->mount_server._address));
kfree(string);
if (cfg->mount_server.addrlen == 0)
goto out_invalid_address;
@@ -789,8 +781,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
- token = match_token(string,
- nfs_lookupcache_tokens, args);
+ token = match_token(string, nfs_lookupcache_tokens, args);
kfree(string);
switch (token) {
case Opt_lookupcache_all:
@@ -804,10 +795,9 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
cfg->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
break;
default:
- dfprintk(MOUNT, "NFS: invalid "
- "lookupcache argument\n");
+ dfprintk(MOUNT, "NFS: invalid lookupcache argument\n");
return -EINVAL;
- };
+ }
break;
case Opt_fscache_uniq:
if (nfs_get_option_str(args, &cfg->fscache_uniq))
@@ -818,8 +808,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
- token = match_token(string, nfs_local_lock_tokens,
- args);
+ token = match_token(string, nfs_local_lock_tokens, args);
kfree(string);
switch (token) {
case Opt_local_lock_all:
@@ -837,8 +826,7 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
NFS_MOUNT_LOCAL_FCNTL);
break;
default:
- dfprintk(MOUNT, "NFS: invalid "
- "local_lock argument\n");
+ dfprintk(MOUNT, "NFS: invalid local_lock argument\n");
return -EINVAL;
};
break;
@@ -852,13 +840,11 @@ static int nfs_sb_config_parse_option(struct nfs_sb_config *cfg, char *p)
break;
case Opt_userspace:
case Opt_deprecated:
- dfprintk(MOUNT, "NFS: ignoring mount option "
- "'%s'\n", p);
+ dfprintk(MOUNT, "NFS: ignoring mount option '%s'\n", p);
break;
default:
- dfprintk(MOUNT, "NFS: unrecognized mount option "
- "'%s'\n", p);
+ dfprintk(MOUNT, "NFS: unrecognized mount option '%s'\n", p);
return -EINVAL;
}
@@ -928,15 +914,15 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
* families in the addr=/mountaddr= options.
*/
if (cfg->protofamily != AF_UNSPEC &&
- cfg->protofamily != cfg->nfs_server.address.ss_family)
+ cfg->protofamily != cfg->nfs_server.address.sa_family)
goto out_proto_mismatch;
if (cfg->mountfamily != AF_UNSPEC) {
if (cfg->mount_server.addrlen) {
- if (cfg->mountfamily != cfg->mount_server.address.ss_family)
+ if (cfg->mountfamily != cfg->mount_server.address.sa_family)
goto out_mountproto_mismatch;
} else {
- if (cfg->mountfamily != cfg->nfs_server.address.ss_family)
+ if (cfg->mountfamily != cfg->nfs_server.address.sa_family)
goto out_mountproto_mismatch;
}
}
@@ -976,9 +962,9 @@ int nfs_parse_mount_options(char *raw, struct nfs_sb_config *cfg)
*
* Note: caller frees hostname and export path, even on error.
*/
-static int nfs_parse_devname(const char *dev_name,
- char **hostname, size_t maxnamlen,
- char **export_path, size_t maxpathlen)
+static int nfs_parse_devname(struct nfs_sb_config *cfg,
+ const char *dev_name,
+ size_t maxnamlen, size_t maxpathlen)
{
size_t len;
char *end;
@@ -1009,17 +995,17 @@ static int nfs_parse_devname(const char *dev_name,
goto out_hostname;
/* N.B. caller will free nfs_server.hostname in all cases */
- *hostname = kstrndup(dev_name, len, GFP_KERNEL);
- if (*hostname == NULL)
+ cfg->nfs_server.hostname = kmemdup_nul(dev_name, len, GFP_KERNEL);
+ if (!cfg->nfs_server.hostname)
goto out_nomem;
len = strlen(++end);
if (len > maxpathlen)
goto out_path;
- *export_path = kstrndup(end, len, GFP_KERNEL);
- if (!*export_path)
+ cfg->nfs_server.export_path = kmemdup_nul(end, len, GFP_KERNEL);
+ if (!cfg->nfs_server.export_path)
goto out_nomem;
- dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
+ dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", cfg->nfs_server.export_path);
return 0;
out_bad_devname:
@@ -1040,7 +1026,7 @@ static int nfs_parse_devname(const char *dev_name,
}
/*
- * Validate the NFS2/NFS3 mount data
+ * Parse monolithic NFS2/NFS3 mount data
* - fills in the mount root filehandle
*
* For option strings, user space handles the following behaviors:
@@ -1365,11 +1351,7 @@ int nfs_validate_text_mount_data(void *options,
nfs_set_port(sap, &cfg->nfs_server.port, port);
- return nfs_parse_devname(dev_name,
- &cfg->nfs_server.hostname,
- max_namelen,
- &cfg->nfs_server.export_path,
- max_pathlen);
+ return nfs_parse_devname(cfg, dev_name, max_namelen, max_pathlen);
#if !IS_ENABLED(CONFIG_NFS_V4)
out_v4_not_compiled:
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 26c1fca31e6b..acf935a6438d 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -795,7 +795,7 @@ static int nfs_request_mount(struct nfs_sb_config *cfg,
/*
* Construct the mount server's address.
*/
- if (cfg->mount_server.address.ss_family == AF_UNSPEC) {
+ if (cfg->mount_server.address.sa_family == AF_UNSPEC) {
memcpy(request.sap, &cfg->nfs_server.address,
cfg->nfs_server.addrlen);
cfg->mount_server.addrlen = cfg->nfs_server.addrlen;
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 10/23] VFS: Remove unused code after superblock config context changes [ver #4] |
| Message-ID | <tJXUv-7yP-57@gated-at.bofh.it> |
| In reply to | #1647066 |
Remove code that is now unused after the superblock config context changes.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/internal.h | 2 --
fs/super.c | 53 ---------------------------------------------
include/linux/lsm_hooks.h | 2 --
include/linux/security.h | 6 -----
security/security.c | 5 ----
security/selinux/hooks.c | 20 -----------------
6 files changed, 88 deletions(-)
diff --git a/fs/internal.h b/fs/internal.h
index 39121a99d930..de9b31568f15 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -89,8 +89,6 @@ extern struct file *get_empty_filp(void);
*/
extern int do_remount_sb(struct super_block *, int, void *, int, struct sb_config *);
extern bool trylock_super(struct super_block *sb);
-extern struct dentry *mount_fs(struct file_system_type *,
- int, const char *, void *);
extern struct super_block *user_get_super(dev_t);
/*
diff --git a/fs/super.c b/fs/super.c
index e4b47d481679..7ca217552977 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1249,59 +1249,6 @@ struct dentry *mount_single(struct file_system_type *fs_type,
}
EXPORT_SYMBOL(mount_single);
-struct dentry *
-mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
-{
- struct dentry *root;
- struct super_block *sb;
- char *secdata = NULL;
- int error = -ENOMEM;
-
- if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
- secdata = alloc_secdata();
- if (!secdata)
- goto out;
-
- error = security_sb_copy_data(data, secdata);
- if (error)
- goto out_free_secdata;
- }
-
- root = type->mount(type, flags, name, data);
- if (IS_ERR(root)) {
- error = PTR_ERR(root);
- goto out_free_secdata;
- }
- sb = root->d_sb;
- BUG_ON(!sb);
- WARN_ON(!sb->s_bdi);
- sb->s_flags |= MS_BORN;
-
- error = security_sb_kern_mount(sb, flags, secdata);
- if (error)
- goto out_sb;
-
- /*
- * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
- * but s_maxbytes was an unsigned long long for many releases. Throw
- * this warning for a little while to try and catch filesystems that
- * violate this rule.
- */
- WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
- "negative value (%lld)\n", type->name, sb->s_maxbytes);
-
- up_write(&sb->s_umount);
- free_secdata(secdata);
- return root;
-out_sb:
- dput(root);
- deactivate_locked_super(sb);
-out_free_secdata:
- free_secdata(secdata);
-out:
- return ERR_PTR(error);
-}
-
/*
* Setup private BDI for given superblock. It gets automatically cleaned up
* in generic_shutdown_super().
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index c2bbd9e92b0a..e95a918e61ca 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1410,7 +1410,6 @@ union security_list_options {
void (*sb_free_security)(struct super_block *sb);
int (*sb_copy_data)(char *orig, char *copy);
int (*sb_remount)(struct super_block *sb, void *data);
- int (*sb_kern_mount)(struct super_block *sb, int flags, void *data);
int (*sb_show_options)(struct seq_file *m, struct super_block *sb);
int (*sb_statfs)(struct dentry *dentry);
int (*sb_mount)(const char *dev_name, const struct path *path,
@@ -1726,7 +1725,6 @@ struct security_hook_heads {
struct list_head sb_free_security;
struct list_head sb_copy_data;
struct list_head sb_remount;
- struct list_head sb_kern_mount;
struct list_head sb_show_options;
struct list_head sb_statfs;
struct list_head sb_mount;
diff --git a/include/linux/security.h b/include/linux/security.h
index d1dfb6abd4f7..f6eb735987d1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -234,7 +234,6 @@ int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
int security_sb_copy_data(char *orig, char *copy);
int security_sb_remount(struct super_block *sb, void *data);
-int security_sb_kern_mount(struct super_block *sb, int flags, void *data);
int security_sb_show_options(struct seq_file *m, struct super_block *sb);
int security_sb_statfs(struct dentry *dentry);
int security_sb_mount(const char *dev_name, const struct path *path,
@@ -566,11 +565,6 @@ static inline int security_sb_remount(struct super_block *sb, void *data)
return 0;
}
-static inline int security_sb_kern_mount(struct super_block *sb, int flags, void *data)
-{
- return 0;
-}
-
static inline int security_sb_show_options(struct seq_file *m,
struct super_block *sb)
{
diff --git a/security/security.c b/security/security.c
index 951f28487719..ed086c6c8f0b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -362,11 +362,6 @@ int security_sb_remount(struct super_block *sb, void *data)
return call_int_hook(sb_remount, 0, sb, data);
}
-int security_sb_kern_mount(struct super_block *sb, int flags, void *data)
-{
- return call_int_hook(sb_kern_mount, 0, sb, flags, data);
-}
-
int security_sb_show_options(struct seq_file *m, struct super_block *sb)
{
return call_int_hook(sb_show_options, 0, m, sb);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 420bfa955fb4..1deafdbf8716 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2775,25 +2775,6 @@ static int selinux_sb_remount(struct super_block *sb, void *data)
goto out_free_opts;
}
-static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
-{
- const struct cred *cred = current_cred();
- struct common_audit_data ad;
- int rc;
-
- rc = superblock_doinit(sb, data);
- if (rc)
- return rc;
-
- /* Allow all mounts performed by the kernel */
- if (flags & MS_KERNMOUNT)
- return 0;
-
- ad.type = LSM_AUDIT_DATA_DENTRY;
- ad.u.dentry = sb->s_root;
- return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
-}
-
static int selinux_sb_statfs(struct dentry *dentry)
{
const struct cred *cred = current_cred();
@@ -6327,7 +6308,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
LSM_HOOK_INIT(sb_copy_data, selinux_sb_copy_data),
LSM_HOOK_INIT(sb_remount, selinux_sb_remount),
- LSM_HOOK_INIT(sb_kern_mount, selinux_sb_kern_mount),
LSM_HOOK_INIT(sb_show_options, selinux_sb_show_options),
LSM_HOOK_INIT(sb_statfs, selinux_sb_statfs),
LSM_HOOK_INIT(sb_mount, selinux_mount),
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 03/23] VFS: Make get_mnt_ns() return the namespace [ver #4] |
| Message-ID | <tJXUw-7yP-71@gated-at.bofh.it> |
| In reply to | #1647066 |
Make get_mnt_ns() return the namespace it got a ref on for consistency with
other namespace ref getting functions.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/mount.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/mount.h b/fs/mount.h
index bf1fda6eed8f..02ef292a77d7 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -108,9 +108,10 @@ static inline void detach_mounts(struct dentry *dentry)
__detach_mounts(dentry);
}
-static inline void get_mnt_ns(struct mnt_namespace *ns)
+static inline struct mnt_namespace *get_mnt_ns(struct mnt_namespace *ns)
{
atomic_inc(&ns->count);
+ return ns;
}
extern seqlock_t mount_lock;
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:00 +0200 |
| Subject | [PATCH 13/23] VFS: Add a sample program for fsopen/fsmount [ver #4] |
| Message-ID | <tJXUw-7yP-65@gated-at.bofh.it> |
| In reply to | #1647066 |
Add a sample program for driving fsopen/fsmount.
Signed-off-by: David Howells <dhowells@redhat.com>
---
samples/fsmount/test-fsmount.c | 92 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 samples/fsmount/test-fsmount.c
diff --git a/samples/fsmount/test-fsmount.c b/samples/fsmount/test-fsmount.c
new file mode 100644
index 000000000000..30caad8e05a3
--- /dev/null
+++ b/samples/fsmount/test-fsmount.c
@@ -0,0 +1,92 @@
+/* fd-based mount test.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+
+#define PR_ERRMSG_ENABLE 48
+#define PR_ERRMSG_READ 49
+
+#define E(x) do { if ((x) == -1) { perror(#x); exit(1); } } while(0)
+
+static __attribute__((noreturn))
+void mount_error(int fd, const char *s)
+{
+ char buf[4096];
+ int err, n, perr;
+
+ do {
+ err = errno;
+ errno = 0;
+ n = prctl(PR_ERRMSG_READ, buf, sizeof(buf));
+ perr = errno;
+ errno = err;
+ if (n > 0) {
+ fprintf(stderr, "Error: '%s': %*.*s: %m\n", s, n, n, buf);
+ } else {
+ fprintf(stderr, "%s: %m\n", s);
+ }
+ } while (perr == 0);
+ exit(1);
+}
+
+#define E_write(fd, s) \
+ do { \
+ if (write(fd, s, sizeof(s) - 1) == -1) \
+ mount_error(fd, s); \
+ } while (0)
+
+static inline int fsopen(const char *fs_name, int reserved, int flags)
+{
+ return syscall(333, fs_name, reserved, flags);
+}
+
+static inline int fsmount(int fsfd, int dfd, const char *path,
+ unsigned int at_flags, unsigned int flags)
+{
+ return syscall(334, fsfd, dfd, path, at_flags, flags);
+}
+
+int main()
+{
+ int mfd;
+
+ if (prctl(PR_ERRMSG_ENABLE, 1) < 0) {
+ perror("prctl/en");
+ exit(1);
+ }
+
+ /* Mount an NFS filesystem */
+ mfd = fsopen("nfs4", -1, 0);
+ if (mfd == -1) {
+ perror("fsopen");
+ exit(1);
+ }
+
+ E_write(mfd, "s warthog:/data");
+ E_write(mfd, "o fsc");
+ E_write(mfd, "o sync");
+ E_write(mfd, "o intr");
+ E_write(mfd, "o vers=4.2");
+ E_write(mfd, "o addr=90.155.74.18");
+ E_write(mfd, "o clientaddr=90.155.74.21");
+ E_write(mfd, "x create");
+ if (fsmount(mfd, AT_FDCWD, "/mnt", 0, 0) < 0)
+ mount_error(mfd, "fsmount");
+ E(close(mfd));
+
+ exit(0);
+}
[toc] | [prev] | [next] | [standalone]
| From | David Howells <dhowells@redhat.com> |
|---|---|
| Date | 2017-05-22 18:10 +0200 |
| Subject | [PATCH 06/23] Provide supplementary error message facility [ver #4] |
| Message-ID | <tJY4a-7To-25@gated-at.bofh.it> |
| In reply to | #1647066 |
Provide a way for the kernel to pass supplementary error messages to
userspace. This will make it easier for userspace, particularly in
containers to find out what went wrong during mounts and automounts, but is
also made available to any other syscalls that want to use it.
Two prctl() functions are added for this:
(1) int old_setting = prctl(PR_ERRMSG_ENABLE, int setting);
Enable (setting == 1) or disable (setting == 0) the facility.
Disabling the facility clears the error buffer.
(2) int size = prctl(PR_ERRMSG_READ, char *buffer, int buf_size);
Reads the next error string into the buffer. The string is truncated
if it won't fit. Strings are discarded as they're read.
If there isn't a string, ENODATA is indicated.
I've done it this way rather than a proc file because procfs might not be
accessible.
The interface inside the kernel is a pair of macros:
(*) void errorf(const char *fmt, ...);
(*) int invalf(const char *fmt, ...);
Both of them snprintf() the string into the current process's error message
buffer if the facility is enabled. The string is truncated if it exceeds
the limit. invalf() returns -EINVAL whereas errof() has no return.
Note that this is very crude and could be made to store multiple strings,
allocate storage as required and not duplicate unformatted strings that are
stored in the rodata section (like kvasprintf_const). Unfortunately,
specially handling rodata strings wouldn't gain a lot as most strings are
likely to be in modules, where the string's life can be terminated by
rmmod.
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/linux/sched.h | 29 +++++++++++++++++++++++++++++
include/uapi/linux/prctl.h | 6 ++++++
kernel/exit.c | 1 +
kernel/fork.c | 1 +
kernel/sys.c | 38 ++++++++++++++++++++++++++++++++++++++
5 files changed, 75 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2b69fc650201..eba196521562 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1051,6 +1051,8 @@ struct task_struct {
/* Used by LSM modules for access restriction: */
void *security;
#endif
+#define ERROR_MSG_SIZE 256
+ char *error_msg;
/* CPU-specific state of this task: */
struct thread_struct thread;
@@ -1573,4 +1575,31 @@ extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
#define TASK_SIZE_OF(tsk) TASK_SIZE
#endif
+/**
+ * errorf - Store supplementary error message
+ * fmt: The format string
+ *
+ * Store the supplementary error message for the process if the process has
+ * enabled the facility.
+ */
+#define errorf(fmt, ...) \
+ do { \
+ if (current->error_msg) \
+ snprintf(current->error_msg, ERROR_MSG_SIZE, fmt, ## __VA_ARGS__); \
+ } while(0)
+
+/**
+ * invalf - Store supplementary invalid argument error message
+ * fmt: The format string
+ *
+ * Store the supplementary error message for the process if the process has
+ * enabled the facility and return -EINVAL.
+ */
+#define invalf(fmt, ...) \
+ ({ \
+ errorf(fmt, ## __VA_ARGS__); \
+ -EINVAL; \
+ })
+
+
#endif
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index a8d0759a9e40..b1203850dac8 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -197,4 +197,10 @@ struct prctl_mm_map {
# define PR_CAP_AMBIENT_LOWER 3
# define PR_CAP_AMBIENT_CLEAR_ALL 4
+/*
+ * Control the supplementary error message gathering facility.
+ */
+#define PR_ERRMSG_ENABLE 48
+#define PR_ERRMSG_READ 49
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/exit.c b/kernel/exit.c
index 516acdb0e0ec..31b8617aee04 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -932,6 +932,7 @@ void __noreturn do_exit(long code)
__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
exit_rcu();
TASKS_RCU(__srcu_read_unlock(&tasks_rcu_exit_srcu, tasks_rcu_i));
+ kfree(tsk->error_msg);
do_task_dead();
}
diff --git a/kernel/fork.c b/kernel/fork.c
index 06d759ab4c62..aec6672d3f0e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1903,6 +1903,7 @@ static __latent_entropy struct task_struct *copy_process(
trace_task_newtask(p, clone_flags);
uprobe_copy_process(p, clone_flags);
+ p->error_msg = NULL;
return p;
diff --git a/kernel/sys.c b/kernel/sys.c
index 8a94b4eabcaa..b784905c4806 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2295,6 +2295,44 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
case PR_GET_FP_MODE:
error = GET_FP_MODE(me);
break;
+
+ case PR_ERRMSG_ENABLE:
+ switch (arg2) {
+ case 0:
+ if (!current->error_msg)
+ return 0;
+ kfree(current->error_msg);
+ current->error_msg = NULL;
+ return 1;
+ case 1:
+ if (current->error_msg)
+ return 1;
+ current->error_msg = kmalloc(ERROR_MSG_SIZE, GFP_KERNEL);
+ if (!current->error_msg)
+ return -ENOMEM;
+ current->error_msg[0] = 0;
+ return 0;
+ default:
+ error = -EINVAL;
+ break;
+ }
+ break;
+
+ case PR_ERRMSG_READ:
+ if (!arg2 || !arg3)
+ return -EINVAL;
+ if (!current->error_msg)
+ return -EINVAL;
+ if (!current->error_msg[0])
+ return -ENODATA;
+ error = strlen(current->error_msg);
+ if (arg3 < error)
+ error = arg3;
+ if (copy_to_user((char __user *)arg2, current->error_msg, error))
+ return -EFAULT;
+ current->error_msg[0] = 0;
+ return error;
+
default:
error = -EINVAL;
break;
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