Hi,
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. (against 2.6.20.4)
Signed-off-by: Lepton Wu <[email protected]>
diff -X linux-2.6.22.6-lepton/Documentation/dontdiff -pru linux-2.6.22.6/fs/reiserfs/dir.c linux-2.6.22.6-lepton/fs/reiserfs/dir.c
--- linux-2.6.22.6/fs/reiserfs/dir.c 2007-09-14 17:41:15.000000000 +0800
+++ linux-2.6.22.6-lepton/fs/reiserfs/dir.c 2007-09-14 18:02:10.000000000 +0800
@@ -121,6 +121,16 @@ static int reiserfs_readdir(struct file
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);