reiserfs: fix kernel panic on corrupted directory
When reading corrupted reiserfs directory data, d_reclen could be a
negative number or a big positive number, this can lead to kernel panic or
oop. The following patch adds a sanity check.
Signed-off-by: Lepton Wu <ytht.net@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/reiserfs/dir.c b/fs/reiserfs/dir.c
index ffbfc2c..e6b03d2 100644
--- a/fs/reiserfs/dir.c
+++ b/fs/reiserfs/dir.c
@@ -121,6 +121,16 @@
continue;
d_reclen = entry_length(bh, ih, entry_num);
d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
+
+ if (d_reclen <= 0 ||
+ d_name + d_reclen > bh->b_data + bh->b_size) {
+ /* There is corrupted data in entry,
+ * We'd better stop here */
+ pathrelse(&path_to_entry);
+ ret = -EIO;
+ goto out;
+ }
+
if (!d_name[d_reclen - 1])
d_reclen = strlen(d_name);