From 849bd151196fd6a7b06c8b2fefd8714f41757946 Mon Sep 17 00:00:00 2001 From: Petr Matousek Date: Thu, 18 Sep 2014 08:35:37 +0200 Subject: slirp: udp: fix NULL pointer dereference because of uninitialized socket Bug-Debian: http://bugs.debian.org/762532 When guest sends udp packet with source port and source addr 0, uninitialized socket is picked up when looking for matching and already created udp sockets, and later passed to sosendto() where NULL pointer dereference is hit during so->slirp->vnetwork_mask.s_addr access. Fix this by checking that the socket is not just a socket stub. This is CVE-2014-3640. Signed-off-by: Petr Matousek Reported-by: Xavier Mehrenberger Reported-by: Stephane Duverger Reviewed-by: Jan Kiszka Reviewed-by: Michael S. Tsirkin Reviewed-by: Michael Tokarev Message-id: 20140918063537.GX9321@dhcp-25-225.brq.redhat.com Signed-off-by: Peter Maydell (cherry picked from commit 01f7cecf0037997cb0e58ec0d56bf9b5a6f7cb2a) Signed-off-by: Michael Tokarev --- slirp/udp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/slirp/udp.c b/slirp/udp.c index ced5096..0c5d8bf 100644 --- a/slirp/udp.c +++ b/slirp/udp.c @@ -152,7 +152,7 @@ udp_input(register struct mbuf *m, int iphlen) * Locate pcb for datagram. */ so = slirp->udp_last_so; - if (so->so_lport != uh->uh_sport || + if (so == &slirp->udb || so->so_lport != uh->uh_sport || so->so_laddr.s_addr != ip->ip_src.s_addr) { struct socket *tmp; -- 1.7.10.4