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| author | Andreas Gruenbacher <agruen@linbit.com> | 2014-01-23 15:56:15 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-23 16:37:04 -0800 |
| commit | 949b9c3d4263c9b7c2448588afce37becd58e1ad (patch) | |
| tree | 9db6da020bb289372cd001a816768f2ececfffc0 | |
| parent | e376ed7c85fe102ff63db2eb8a0c5595f68151fa (diff) | |
| download | lwn-949b9c3d4263c9b7c2448588afce37becd58e1ad.tar.gz lwn-949b9c3d4263c9b7c2448588afce37becd58e1ad.zip | |
userns: relax the posix_acl_valid() checks
So far, POSIX ACLs are using a canonical representation that keeps all ACL
entries in a strict order; the ACL_USER and ACL_GROUP entries for specific
users and groups are ordered by user and group identifier, respectively.
The user-space code provides ACL entries in this order; the kernel
verifies that the ACL entry order is correct in posix_acl_valid().
User namespaces allow to arbitrary map user and group identifiers which
can cause the ACL_USER and ACL_GROUP entry order to differ between user
space and the kernel; posix_acl_valid() would then fail.
Work around this by allowing ACL_USER and ACL_GROUP entries to be in any
order in the kernel. The effect is only minor: file permission checks
will pick the first matching ACL_USER entry, and check all matching
ACL_GROUP entries.
(The libacl user-space library and getfacl / setfacl tools will not create
ACLs with duplicate user or group idenfifiers; they will handle ACLs with
entries in an arbitrary order correctly.)
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/posix_acl.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 021e7c069b86..551e61ba15b6 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -149,8 +149,6 @@ posix_acl_valid(const struct posix_acl *acl) { const struct posix_acl_entry *pa, *pe; int state = ACL_USER_OBJ; - kuid_t prev_uid = INVALID_UID; - kgid_t prev_gid = INVALID_GID; int needs_mask = 0; FOREACH_ACL_ENTRY(pa, acl, pe) { @@ -169,10 +167,6 @@ posix_acl_valid(const struct posix_acl *acl) return -EINVAL; if (!uid_valid(pa->e_uid)) return -EINVAL; - if (uid_valid(prev_uid) && - uid_lte(pa->e_uid, prev_uid)) - return -EINVAL; - prev_uid = pa->e_uid; needs_mask = 1; break; @@ -188,10 +182,6 @@ posix_acl_valid(const struct posix_acl *acl) return -EINVAL; if (!gid_valid(pa->e_gid)) return -EINVAL; - if (gid_valid(prev_gid) && - gid_lte(pa->e_gid, prev_gid)) - return -EINVAL; - prev_gid = pa->e_gid; needs_mask = 1; break; |