xfs: sanitize remount options
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@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 9e1538d..8dd7d16 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -172,13 +172,17 @@
*
* Note that this function leaks the various device name allocations on
* failure. The caller takes care of them.
+ *
+ * *sb is const because this is also used to test options on the remount
+ * path, and we don't want this to have any side effects at remount time.
+ * Today this function does not change *sb, but just to future-proof...
*/
STATIC int
xfs_parseargs(
struct xfs_mount *mp,
char *options)
{
- struct super_block *sb = mp->m_super;
+ const struct super_block *sb = mp->m_super;
char *p;
substring_t args[MAX_OPT_ARGS];
int dsunit = 0;
@@ -1170,6 +1174,27 @@
}
STATIC int
+xfs_test_remount_options(
+ struct super_block *sb,
+ struct xfs_mount *mp,
+ char *options)
+{
+ int error = 0;
+ struct xfs_mount *tmp_mp;
+
+ tmp_mp = kmem_zalloc(sizeof(*tmp_mp), KM_MAYFAIL);
+ if (!tmp_mp)
+ return -ENOMEM;
+
+ tmp_mp->m_super = sb;
+ error = xfs_parseargs(tmp_mp, options);
+ xfs_free_fsname(tmp_mp);
+ kfree(tmp_mp);
+
+ return error;
+}
+
+STATIC int
xfs_fs_remount(
struct super_block *sb,
int *flags,
@@ -1181,6 +1206,11 @@
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;