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Groups > linux.kernel > #1219502
| From | Andreas Gruenbacher <agruenba@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [RFC v7 15/41] richacl: Automatic Inheritance |
| Date | 2015-09-05 12:40 +0200 |
| Message-ID | <q5j35-6jH-65@gated-at.bofh.it> (permalink) |
| References | <q5iTn-686-5@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 file create time. In addition, it makes sure that
permission propagation is turned off when the permissions of a file 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 is not set,
the file 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 is set, AI
will not modify the acl of the file. 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 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. This is a workaround; a mechanism that would allow a process to
indicate to the kernel to ignore the create mode when there are
inherited permissions would fix this problem.
Signed-off-by: Andreas Gruenbacher <agruenba@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 fda407d..a85b7a3 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;
}
@@ -549,6 +552,11 @@ 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 f3f1f84..df175c1 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -247,6 +247,13 @@ 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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[RFC v7 00/41] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:30 +0200
[RFC v7 21/41] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 21/41] richacl: Move everyone@ aces down the acl bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 21:40 +0200
Re: [RFC v7 21/41] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-21 23:50 +0200
Re: [RFC v7 21/41] richacl: Move everyone@ aces down the acl "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-22 04:00 +0200
[RFC v7 26/41] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 33/41] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 28/41] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 02/41] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 38/41] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode bfields@fieldses.org (J. Bruce Fields) - 2015-09-17 20:30 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-18 03:00 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-09-21 16:00 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 16:40 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-09-21 19:10 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 19:50 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 17:40 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-22 01:30 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-22 01:30 +0200
Re: [RFC v7 13/41] richacl: Check if an acl is equivalent to a file mode bfields@fieldses.org (J. Bruce Fields) - 2015-09-17 20:40 +0200
[RFC v7 23/41] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 23/41] richacl: Set the owner permissions to the owner mask bfields@fieldses.org (J. Bruce Fields) - 2015-09-21 23:10 +0200
[RFC v7 11/41] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 10/41] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 10/41] richacl: Permission check algorithm bfields@fieldses.org (J. Bruce Fields) - 2015-09-11 23:20 +0200
Re: [RFC v7 10/41] richacl: Permission check algorithm Andreas Grünbacher <andreas.gruenbacher@gmail.com> - 2015-09-12 00:20 +0200
Re: [RFC v7 10/41] richacl: Permission check algorithm "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-17 19:40 +0200
[RFC v7 07/41] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 34/41] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 12/41] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 01/41] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 17/41] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 18/41] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 30/41] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 14/41] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 14/41] richacl: Create-time inheritance bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 20:00 +0200
Re: [RFC v7 14/41] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-21 22:40 +0200
[RFC v7 40/41] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 29/41] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 16/41] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 08/41] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 20/41] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 20/41] richacl: acl editing helper functions bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 21:00 +0200
[RFC v7 05/41] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 24/41] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 31/41] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 39/41] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 15/41] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 15/41] richacl: Automatic Inheritance bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 20:50 +0200
Re: [RFC v7 15/41] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-21 23:30 +0200
Re: [RFC v7 15/41] richacl: Automatic Inheritance "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-22 04:00 +0200
[RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces bfields@fieldses.org (J. Bruce Fields) - 2015-09-18 23:40 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-22 01:50 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces bfields@fieldses.org (J. Bruce Fields) - 2015-09-19 00:00 +0200
Re: [RFC v7 22/41] richacl: Propagate everyone@ permissions to other aces "J. Bruce Fields" <bfields@fieldses.org> - 2015-09-21 21:30 +0200
[RFC v7 41/41] richacl: uapi header split Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 09/41] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
Re: [RFC v7 09/41] richacl: Update the file masks in chmod() bfields@fieldses.org (J. Bruce Fields) - 2015-09-11 22:40 +0200
[RFC v7 03/41] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[PATCH] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-06 10:20 +0200
Re: [PATCH] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags bfields@fieldses.org (J. Bruce Fields) - 2015-09-11 22:40 +0200
[RFC v7 27/41] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 25/41] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 19/41] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 32/41] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:40 +0200
[RFC v7 37/41] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:50 +0200
[RFC v7 36/41] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:50 +0200
[RFC v7 35/41] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-09-05 12:50 +0200
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