Check whether the size is within bounds before using it.
If the size is not correct, abort and dump the bad data node.
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Silvio Cesare <silvio.cesare@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1e51764a3c2ac ("UBIFS: add new flash file system")
Reported-by: Silvio Cesare <silvio.cesare@xxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
fs/ubifs/journal.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index da8afdfccaa6..eea12d25a58b 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -1387,7 +1387,16 @@ int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
else if (err)
goto out_free;
else {
- if (le32_to_cpu(dn->size) <= dlen)
+ int dn_len = le32_to_cpu(dn->size);
+
+ if (dn_len <= 0 || dn_len > UBIFS_BLOCK_SIZE) {
+ ubifs_err(c, "bad data node (block %u, inode %lu)",
+ blk, inode->i_ino);
+ ubifs_dump_node(c, dn);
+ goto out_free;
+ }
+
+ if (dn_len <= dlen)
dlen = 0; /* Nothing to do */
else {
err = truncate_data_node(c, inode, blk, dn, &dlen);
--
2.18.0
