From: Willem de Bruijn <willemb@google.com> Date: Thu, 22 Dec 2016 23:19:16 +0000 (-0500) Subject: inet: fix IP(V6)_RECVORIGDSTADDR for udp sockets X-Git-Tag: v4.10-rc1~16^2~5 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=39b2dd765e0711e1efd1d1df089473a8dd93ad48;p=users%2Fdwmw2%2Flinux.git inet: fix IP(V6)_RECVORIGDSTADDR for udp sockets Socket cmsg IP(V6)_RECVORIGDSTADDR checks that port range lies within the packet. For sockets that have transport headers pulled, transport offset can be negative. Use signed comparison to avoid overflow. Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing") Reported-by: Nisar Jagabar <njagabar@cloudmark.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 8b13881ed0644..976073417b03c 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -148,7 +148,7 @@ static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb) const struct iphdr *iph = ip_hdr(skb); __be16 *ports = (__be16 *)skb_transport_header(skb); - if (skb_transport_offset(skb) + 4 > skb->len) + if (skb_transport_offset(skb) + 4 > (int)skb->len) return; /* All current transport protocols have the port numbers in the diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c index 0489e19258ade..1407426bc862d 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -701,7 +701,7 @@ void ip6_datagram_recv_specific_ctl(struct sock *sk, struct msghdr *msg, struct sockaddr_in6 sin6; __be16 *ports = (__be16 *) skb_transport_header(skb); - if (skb_transport_offset(skb) + 4 <= skb->len) { + if (skb_transport_offset(skb) + 4 <= (int)skb->len) { /* All current transport protocols have the port numbers in the * first four bytes of the transport header and this function is * written with this assumption in mind.