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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/btrfs | |
| parent | 5d3ddd84eaefffd23c028bce5610dac8726f71c1 (diff) | |
| download | linux-073931017b49d9458aa351605b43a7e34598caef.tar.gz linux-073931017b49d9458aa351605b43a7e34598caef.tar.bz2 linux-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/btrfs')
| -rw-r--r-- | fs/btrfs/acl.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index 53bb7af4e5f0..247b8dfaf6e5 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -79,11 +79,9 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, case ACL_TYPE_ACCESS: name = XATTR_NAME_POSIX_ACL_ACCESS; if (acl) { - ret = posix_acl_equiv_mode(acl, &inode->i_mode); - if (ret < 0) + ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); + if (ret) return ret; - if (ret == 0) - acl = NULL; } ret = 0; break; |