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| author | Jan Kara <jack@suse.cz> | 2016-09-19 17:39:09 +0200 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2016-09-22 10:55:32 +0200 |
| commit | 073931017b49d9458aa351605b43a7e34598caef (patch) | |
| tree | 8c4374e82e5cad92bdb589e5be417f1a94870399 /fs/xfs/xfs_acl.c | |
| parent | 5d3ddd84eaefffd23c028bce5610dac8726f71c1 (diff) | |
| download | lwn-073931017b49d9458aa351605b43a7e34598caef.tar.gz lwn-073931017b49d9458aa351605b43a7e34598caef.zip | |
posix_acl: Clear SGID bit when setting file permissions
When file permissions are modified via chmod(2) and the user is not in
the owning group or capable of CAP_FSETID, the setgid bit is cleared in
inode_change_ok(). Setting a POSIX ACL via setxattr(2) sets the file
permissions as well as the new ACL, but doesn't clear the setgid bit in
a similar way; this allows to bypass the check in chmod(2). Fix that.
References: CVE-2016-7097
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/xfs/xfs_acl.c')
| -rw-r--r-- | fs/xfs/xfs_acl.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c index b6e527b8eccb..8a0dec89ca56 100644 --- a/fs/xfs/xfs_acl.c +++ b/fs/xfs/xfs_acl.c @@ -257,16 +257,11 @@ xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) return error; if (type == ACL_TYPE_ACCESS) { - umode_t mode = inode->i_mode; - error = posix_acl_equiv_mode(acl, &mode); - - if (error <= 0) { - acl = NULL; - - if (error < 0) - return error; - } + umode_t mode; + error = posix_acl_update_mode(inode, &mode, &acl); + if (error) + return error; error = xfs_set_mode(inode, mode); if (error) return error; |