Currently XFS calls file_remove_suid() without holding i_mutex. This is
wrong because that function can end up messing with file permissions and
security xattrs for which we need i_mutex held.
Fix the problem by grabbing iolock exclusively when we will need to
change anything in permissions / xattrs.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/xfs/xfs_file.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index eb596b419942..ad6636ac4943 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -521,6 +521,18 @@ restart:
if (error)
return error;
+ /* For changing security info in file_remove_suid() we need i_mutex */
+ if (!IS_NOSEC(inode) && *iolock == XFS_IOLOCK_SHARED) {
+ struct dentry *dentry = file->f_path.dentry;
+
+ if (should_remove_suid(dentry) ||
+ security_inode_need_killpriv(dentry)) {
+ xfs_rw_iunlock(ip, *iolock);
+ *iolock = XFS_IOLOCK_EXCL;
+ xfs_rw_ilock(ip, *iolock);
+ goto restart;
+ }
+ }
/*
* If the offset is beyond the size of the file, we need to zero any
* blocks that fall between the existing EOF and the start of this
--
1.8.1.4
_______________________________________________
xfs mailing list
xfs@xxxxxxxxxxx
http://oss.sgi.com/mailman/listinfo/xfs
