From 7a4957b92965755a246b52c4721a6c9a47f5bf31 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 26 Jun 2013 04:15:07 -0700 Subject: ipv6: ip6_sk_dst_check() must not assume ipv6 dst [ Upstream commit a963a37d384d71ad43b3e9e79d68d42fbe0901f3 ] It's possible to use AF_INET6 sockets and to connect to an IPv4 destination. After this, socket dst cache is a pointer to a rtable, not rt6_info. ip6_sk_dst_check() should check the socket dst cache is IPv6, or else various corruptions/crashes can happen. Dave Jones can reproduce immediate crash with trinity -q -l off -n -c sendmsg -c connect With help from Hannes Frederic Sowa Reported-by: Dave Jones Reported-by: Hannes Frederic Sowa Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_output.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4e49ab0..1fea459 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -925,11 +925,17 @@ static struct dst_entry *ip6_sk_dst_check(struct sock *sk, const struct flowi6 *fl6) { struct ipv6_pinfo *np = inet6_sk(sk); - struct rt6_info *rt = (struct rt6_info *)dst; + struct rt6_info *rt; if (!dst) goto out; + if (dst->ops->family != AF_INET6) { + dst_release(dst); + return NULL; + } + + rt = (struct rt6_info *)dst; /* Yes, checking route validity in not connected * case is not very simple. Take into account, * that we do not support routing by source, TOS, -- cgit v1.1