Commit a963a37d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

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: default avatarDave Jones <>
Reported-by: default avatarHannes Frederic Sowa <>
Signed-off-by: default avatarEric Dumazet <>
Acked-by: default avatarHannes Frederic Sowa <>
Signed-off-by: default avatarDavid S. Miller <>
parent 5dbe7c17
......@@ -821,11 +821,17 @@ 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) {
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,
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