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, sizeof(udp6_addr.sin6_addr));