diff mbox

[Lucid,CVE-2013-2232] ipv6: ip6_sk_dst_check() must not assume ipv6 dst

Message ID 1373288294-2628-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques July 8, 2013, 12:58 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

BugLink: http://bugs.launchpad.net/bugs/1198293

CVE-2013-2232

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>
(cherry picked from commit a963a37d384d71ad43b3e9e79d68d42fbe0901f3)

Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 net/ipv6/ip6_output.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Tim Gardner July 8, 2013, 1:43 p.m. UTC | #1
diff mbox

Patch

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 365bfc3..ba73a36 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -920,11 +920,17 @@  static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 					  struct flowi *fl)
 {
 	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,