From: Eric Dumazet Date: Wed, 26 Jun 2013 11:15:07 +0000 (-0700) Subject: ipv6: ip6_sk_dst_check() must not assume ipv6 dst X-Git-Tag: v3.0.88~31 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a4957b92965755a246b52c4721a6c9a47f5bf31;p=thirdparty%2Fkernel%2Fstable.git 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 --- diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4e49ab07c462a..1fea45978478c 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,