4.9-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 64199fc0a46ba211362472f7f942f900af9492fd ]
Caching ip_hdr(skb) before a call to pskb_may_pull() is buggy, do not do it.
Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Willem de Bruijn willemb@google.com Reported-by: syzbot syzkaller@googlegroups.com Acked-by: Willem de Bruijn willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/ip_sockglue.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -134,7 +134,6 @@ static void ip_cmsg_recv_security(struct static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb) { struct sockaddr_in sin; - const struct iphdr *iph = ip_hdr(skb); __be16 *ports; int end;
@@ -149,7 +148,7 @@ static void ip_cmsg_recv_dstaddr(struct ports = (__be16 *)skb_transport_header(skb);
sin.sin_family = AF_INET; - sin.sin_addr.s_addr = iph->daddr; + sin.sin_addr.s_addr = ip_hdr(skb)->daddr; sin.sin_port = ports[1]; memset(sin.sin_zero, 0, sizeof(sin.sin_zero));