ipv6: ip6_sk_dst_check() must not assume ipv6 dst
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 <davej@redhat.com>
Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 95703ba..d5d20cd 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -821,11 +821,17 @@
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,
