[PATCH 4.9 09/71] ipv6: explicitly initialize udp6_addr in udp_sock_create6()

From: Greg Kroah-Hartman
Date: Mon Jan 07 2019 - 08:06:29 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: Cong Wang <xiyou.wangcong@xxxxxxxxx>

[ Upstream commit fb24274546310872eeeaf3d1d53799d8414aa0f2 ]

syzbot reported the use of uninitialized udp6_addr::sin6_scope_id.
We can just set ::sin6_scope_id to zero, as tunnels are unlikely
to use an IPv6 address that needs a scope id and there is no
interface to bind in this context.

For net-next, it looks different as we have cfg->bind_ifindex there
so we can probably call ipv6_iface_scope_id().

Same for ::sin6_flowinfo, tunnels don't use it.

Fixes: 8024e02879dd ("udp: Add udp_sock_create for UDP tunnels to open listener socket")
Reported-by: syzbot+c56449ed3652e6720f30@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Jon Maloy <jon.maloy@xxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/ipv6/ip6_udp_tunnel.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -15,7 +15,7 @@
int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
struct socket **sockp)
- struct sockaddr_in6 udp6_addr;
+ struct sockaddr_in6 udp6_addr = {};
int err;
struct socket *sock = NULL;

@@ -42,6 +42,7 @@ int udp_sock_create6(struct net *net, st
goto error;

if (cfg->peer_udp_port) {
+ memset(&udp6_addr, 0, sizeof(udp6_addr));
udp6_addr.sin6_family = AF_INET6;
memcpy(&udp6_addr.sin6_addr, &cfg->peer_ip6,