xfs: check directory name validity

Check directory entry names for invalid characters.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index 229152cd1a24..156ce95c9c45 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -703,3 +703,20 @@ xfs_dir2_shrink_inode(
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 	return 0;
 }
+
+/* Returns true if the directory entry name is valid. */
+bool
+xfs_dir2_namecheck(
+	const void	*name,
+	size_t		length)
+{
+	/*
+	 * MAXNAMELEN includes the trailing null, but (name/length) leave it
+	 * out, so use >= for the length check.
+	 */
+	if (length >= MAXNAMELEN)
+		return false;
+
+	/* There shouldn't be any slashes or nulls here */
+	return !memchr(name, '/', length) && !memchr(name, 0, length);
+}