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@xxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Theodore Tso <tytso@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
---
fs/posix_acl.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 8bd2135..1b30b11 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -78,8 +78,6 @@ 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) {
@@ -98,10 +96,6 @@ 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;
@@ -117,10 +111,6 @@ 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;
--
1.8.1.4
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