From d36a1cb1e3285ba7eb1bcff5b231b4786deefc5b Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Thu, 22 Dec 2016 18:19:16 -0500 Subject: [PATCH] inet: fix IP(V6)_RECVORIGDSTADDR for udp sockets [ Upstream commit 39b2dd765e0711e1efd1d1df089473a8dd93ad48 ] 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 Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_sockglue.c | 2 +- net/ipv6/datagram.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index b8a2d63d1fb8..e869773e3979 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -137,7 +137,7 @@ 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 ccf40550c475..8616d17cf08f 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -700,7 +700,7 @@ 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. -- 2.39.5