x25: Prevent skb overreads when checking call user data

x25_find_listener does not check that the amount of call user data given
in the skb is big enough in per-socket comparisons, hence buffer
overreads may occur.  Fix this by adding a check.

Signed-off-by: Matthew Daley <mattjd@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: stable <stable@kernel.org>
Acked-by: Andrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matthew Daley 2011-10-14 18:45:05 +00:00 committed by David S. Miller
parent cb101ed2c3
commit 7f81e25bef
1 changed files with 2 additions and 1 deletions

View File

@ -295,7 +295,8 @@ static struct sock *x25_find_listener(struct x25_address *addr,
* Found a listening socket, now check the incoming
* call user data vs this sockets call user data
*/
if(skb->len > 0 && x25_sk(s)->cudmatchlength > 0) {
if (x25_sk(s)->cudmatchlength > 0 &&
skb->len >= x25_sk(s)->cudmatchlength) {
if((memcmp(x25_sk(s)->calluserdata.cuddata,
skb->data,
x25_sk(s)->cudmatchlength)) == 0) {