xfs: add parent pointer validator functions

The attr name of a parent pointer is a string, and the attr value of a
parent pointer is (more or less) a file handle.  So we need to modify
attr_namecheck to verify the parent pointer name, and add a
xfs_parent_valuecheck function to sanitize the handle.  At the same
time, we need to validate attr values during log recovery if the xattr
is really a parent pointer.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
[djwong: move functions to xfs_parent.c, adjust for new disk format]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 78c87c405e33..93524efa6e56 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -26,6 +26,7 @@
 #include "xfs_trace.h"
 #include "xfs_attr_item.h"
 #include "xfs_xattr.h"
+#include "xfs_parent.h"
 
 struct kmem_cache		*xfs_attr_intent_cache;
 
@@ -1568,6 +1569,10 @@ xfs_attr_namecheck(
 	if (length >= MAXNAMELEN)
 		return false;
 
+	/* Parent pointers have their own validation. */
+	if (attr_flags & XFS_ATTR_PARENT)
+		return xfs_parent_namecheck(attr_flags, name, length);
+
 	/* There shouldn't be any nulls here */
 	return !memchr(name, 0, length);
 }