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Groups > linux.kernel > #1233754
| From | Andreas Gruenbacher <agruenba@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v8 15/41] richacl: Automatic Inheritance |
| Date | 2015-09-28 00:20 +0200 |
| Message-ID | <qdssx-3tp-3@gated-at.bofh.it> (permalink) |
| References | <qdsiR-3hB-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Automatic Inheritance (AI) allows changes to the acl of a directory to
propagate down to children.
This is mostly implemented in user space: when a process changes the
permissions of a directory and Automatic Inheritance is enabled for that
directory, the process must propagate those changes to all children,
recursively.
The kernel enables this by keeping track of which permissions have been
inherited at create time. In addition, it makes sure that permission
propagation is turned off when the permissions are set explicitly (for
example, upon create or chmod).
Automatic Inheritance works as follows:
- When the RICHACL_AUTO_INHERIT flag in the acl of a file or directory
is not set, the file or directory is not affected by AI.
- When the RICHACL_AUTO_INHERIT flag in the acl of a directory is set
and a file or subdirectory is created in that directory, the
inherited acl will have the RICHACL_AUTO_INHERIT flag set, and all
inherited aces will have the RICHACE_INHERITED_ACE flag set. This
allows user space to distinguish between aces which have been
inherited and aces which have been explicitly added.
- When the RICHACL_PROTECTED acl flag in the acl of a file or directory
is set, AI will not modify the acl. This does not affect propagation
of permissions from the file to its children (if the file is a
directory).
Linux does not have a way of creating files or directories without setting the
file permission bits, so all files created inside a directory with
RICHACL_AUTO_INHERIT set will have the RICHACL_PROTECTED flag set. This
effectively disables Automatic Inheritance.
Protocols which support creating files without specifying permissions can
explicitly clear the RICHACL_PROTECTED flag after creating a file and reset the
file masks to "undo" applying the create mode; see richacl_compute_max_masks().
They should set the RICHACL_DEFAULTED flag. (A mechanism that would allow to
indicate to the kernel to ignore the create mode in the first place when there
are inherited permissions would be nice to have.)
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
fs/richacl_base.c | 10 +++++++++-
fs/richacl_inode.c | 7 +++++++
include/linux/richacl.h | 23 ++++++++++++++++++++++-
3 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index c1490c7..e0357ae 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -363,7 +363,8 @@ richacl_chmod(struct richacl *acl, mode_t mode)
if (acl->a_owner_mask == owner_mask &&
acl->a_group_mask == group_mask &&
acl->a_other_mask == other_mask &&
- (acl->a_flags & (RICHACL_WRITE_THROUGH | RICHACL_MASKED)))
+ (acl->a_flags & (RICHACL_WRITE_THROUGH | RICHACL_MASKED)) &&
+ (!richacl_is_auto_inherit(acl) || richacl_is_protected(acl)))
return acl;
clone = richacl_clone(acl, GFP_KERNEL);
@@ -375,6 +376,8 @@ richacl_chmod(struct richacl *acl, mode_t mode)
clone->a_owner_mask = owner_mask;
clone->a_group_mask = group_mask;
clone->a_other_mask = other_mask;
+ if (richacl_is_auto_inherit(clone))
+ clone->a_flags |= RICHACL_PROTECTED;
return clone;
}
@@ -548,6 +551,11 @@ richacl_inherit(const struct richacl *dir_acl, int isdir)
ace++;
}
}
+ if (richacl_is_auto_inherit(dir_acl)) {
+ acl->a_flags = RICHACL_AUTO_INHERIT;
+ richacl_for_each_entry(ace, acl)
+ ace->e_flags |= RICHACE_INHERITED_ACE;
+ }
return acl;
}
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index 737f054..d451e83 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -248,6 +248,13 @@ richacl_inherit_inode(const struct richacl *dir_acl, struct inode *inode)
richacl_put(acl);
acl = NULL;
} else {
+ /*
+ * We need to set RICHACL_PROTECTED because we are
+ * doing an implicit chmod
+ */
+ if (richacl_is_auto_inherit(acl))
+ acl->a_flags |= RICHACL_PROTECTED;
+
richacl_compute_max_masks(acl);
/*
* Ensure that the acl will not grant any permissions
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 9bf95c2..832b06c 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -53,10 +53,16 @@ struct richacl {
_ace--)
/* a_flags values */
+#define RICHACL_AUTO_INHERIT 0x01
+#define RICHACL_PROTECTED 0x02
+#define RICHACL_DEFAULTED 0x04
#define RICHACL_WRITE_THROUGH 0x40
#define RICHACL_MASKED 0x80
#define RICHACL_VALID_FLAGS ( \
+ RICHACL_AUTO_INHERIT | \
+ RICHACL_PROTECTED | \
+ RICHACL_DEFAULTED | \
RICHACL_WRITE_THROUGH | \
RICHACL_MASKED)
@@ -70,6 +76,7 @@ struct richacl {
#define RICHACE_NO_PROPAGATE_INHERIT_ACE 0x0004
#define RICHACE_INHERIT_ONLY_ACE 0x0008
#define RICHACE_IDENTIFIER_GROUP 0x0040
+#define RICHACE_INHERITED_ACE 0x0080
#define RICHACE_SPECIAL_WHO 0x4000
#define RICHACE_VALID_FLAGS ( \
@@ -78,13 +85,15 @@ struct richacl {
RICHACE_NO_PROPAGATE_INHERIT_ACE | \
RICHACE_INHERIT_ONLY_ACE | \
RICHACE_IDENTIFIER_GROUP | \
+ RICHACE_INHERITED_ACE | \
RICHACE_SPECIAL_WHO)
#define RICHACE_INHERITANCE_FLAGS ( \
RICHACE_FILE_INHERIT_ACE | \
RICHACE_DIRECTORY_INHERIT_ACE | \
RICHACE_NO_PROPAGATE_INHERIT_ACE | \
- RICHACE_INHERIT_ONLY_ACE )
+ RICHACE_INHERIT_ONLY_ACE | \
+ RICHACE_INHERITED_ACE )
/* e_mask bitflags */
#define RICHACE_READ_DATA 0x00000001
@@ -195,6 +204,18 @@ extern void set_cached_richacl(struct inode *, struct richacl *);
extern void forget_cached_richacl(struct inode *);
extern struct richacl *get_richacl(struct inode *);
+static inline int
+richacl_is_auto_inherit(const struct richacl *acl)
+{
+ return acl->a_flags & RICHACL_AUTO_INHERIT;
+}
+
+static inline int
+richacl_is_protected(const struct richacl *acl)
+{
+ return acl->a_flags & RICHACL_PROTECTED;
+}
+
/**
* richace_is_owner - check if @ace is an OWNER@ entry
*/
--
2.4.3
--
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[PATCH v8 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:10 +0200
[PATCH v8 31/41] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 15/41] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 03/41] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 12/41] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 14/41] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 33/41] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 06/41] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 09/41] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
Re: [PATCH v8 09/41] richacl: Update the file masks in chmod() "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 17:30 +0200
Re: [PATCH v8 09/41] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-29 01:50 +0200
[PATCH v8 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 27/41] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 19/41] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 21/41] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 20/41] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 32/41] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 26/41] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 01/41] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 41/41] richacl: uapi header split Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 18/41] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 17/41] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 35/41] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 38/41] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 36/41] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 16/41] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 25/41] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 40/41] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 11/41] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 08/41] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 34/41] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 05/41] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 28/41] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 04/41] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 22/41] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 37/41] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 29/41] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 39/41] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:20 +0200
[PATCH v8 24/41] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:30 +0200
[PATCH v8 23/41] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:30 +0200
[PATCH v8 30/41] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:30 +0200
[PATCH v8 07/41] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:40 +0200
[PATCH v8 10/41] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:40 +0200
Re: [PATCH v8 10/41] richacl: Permission check algorithm "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 18:10 +0200
Re: [PATCH v8 10/41] richacl: Permission check algorithm Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-28 18:30 +0200
Re: [PATCH v8 10/41] richacl: Permission check algorithm "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 18:30 +0200
Re: [PATCH v8 10/41] richacl: Permission check algorithm Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-28 19:00 +0200
[PATCH v8 02/41] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-28 00:50 +0200
Re: [PATCH v8 00/41] Richacls "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 18:40 +0200
Re: [PATCH v8 00/41] Richacls Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-28 19:20 +0200
Re: [PATCH v8 00/41] Richacls "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-28 19:50 +0200
Re: [PATCH v8 00/41] Richacls Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-29 17:00 +0200
Re: [PATCH v8 00/41] Richacls Christoph Hellwig <hch@infradead.org> - 2015-10-04 08:30 +0200
Re: [PATCH v8 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-05 20:50 +0200
Re: [PATCH v8 00/41] Richacls Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-10-05 21:00 +0200
Re: [PATCH v8 00/41] Richacls Dave Chinner <david@fromorbit.com> - 2015-10-05 23:20 +0200
Re: [PATCH v8 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-06 00:10 +0200
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