[PATCH 2/3] xfs: sanitize remount options

[Eric Sandeen]

Perform basic sanitization of remount options by
passing the option string and a dummy mount structure
through xfs_parseargs and returning the result.

Signed-off-by: Eric Sandeen <sandeen at redhat.com>
---

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 934233a..d1cd4fa 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1168,6 +1168,27 @@ xfs_quiesce_attr(
 }
 
 STATIC int
+xfs_test_remount_options(
+	struct super_block	*sb,
+	struct xfs_mount	*mp,
+	char			*options)
+{
+	int			error = 0;
+	struct xfs_mount	*tmp;
+
+	tmp = kmem_zalloc(sizeof(*tmp), KM_MAYFAIL);
+	if (!tmp)
+		return -ENOMEM;
+
+	tmp->m_super = sb;
+	error = xfs_parseargs(tmp, options);
+	xfs_free_fsname(tmp);
+	kfree(tmp);
+
+	return error;
+}
+
+STATIC int
 xfs_fs_remount(
 	struct super_block	*sb,
 	int			*flags,
@@ -1179,6 +1200,11 @@ xfs_fs_remount(
 	char			*p;
 	int			error;
 
+	/* First, check for complete junk; i.e. invalid options */
+	error = xfs_test_remount_options(sb, mp, options);
+	if (error)
+		return error;
+
 	sync_filesystem(sb);
 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;