slirp: udp: fix NULL pointer dereference because of uninitialized socket
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 <pmatouse@redhat.com>
Reported-by: Xavier Mehrenberger <xavier.mehrenberger@airbus.com>
Reported-by: Stephane Duverger <stephane.duverger@eads.net>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Message-id: 20140918063537.GX9321@dhcp-25-225.brq.redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 01f7cecf0037997cb0e58ec0d56bf9b5a6f7cb2a)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
diff --git a/slirp/udp.c b/slirp/udp.c
index 8cc6cb6..f77e00f 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -152,7 +152,7 @@
* 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;
