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, 10 insertions, 0 deletions

diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index 2898eeb16366..2b10ac4c5fce 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -27,6 +27,7 @@
 #include "xfs_error.h"
 #include "xfs_log_priv.h"
 #include "xfs_log_recover.h"
+#include "xfs_parent.h"
 
 struct kmem_cache		*xfs_attri_cache;
 struct kmem_cache		*xfs_attrd_cache;
@@ -973,6 +974,15 @@ xfs_attri_validate_value_iovec(
 		return NULL;
 	}
 
+	if ((attri_formatp->alfi_attr_filter & XFS_ATTR_PARENT) &&
+	    !xfs_parent_valuecheck(mp, iovec->i_addr, value_len)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
+				attri_formatp, sizeof(*attri_formatp));
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
+				iovec->i_addr, iovec->i_len);
+		return NULL;
+	}
+
 	return iovec->i_addr;
 }