From 72760fea8e88dac78985e6f493c1f86b90c1fc0d Mon Sep 17 00:00:00 2001 From: Matthew Daley Date: Fri, 14 Oct 2011 18:45:05 +0000 Subject: [PATCH] x25: Prevent skb overreads when checking call user data commit 7f81e25befdfb3272345a2e775f520e1d515fa20 upstream. 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 Cc: Eric Dumazet Cc: Andrew Hendry Acked-by: Andrew Hendry Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/x25/af_x25.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index d00681646d1d..2e9e30025d60 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -294,7 +294,8 @@ 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) { -- 2.39.5