netdev - [PATCH] bridge: mcast snooping, fix length check of snooped MLDv1/2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 27 Mar 2011 08:27:24 +0200
From:	Linus Lüssing <linus.luessing@....de>
To:	bridge@...ts.linux-foundation.org
Cc:	Stephen Hemminger <shemminger@...ux-foundation.org>,
	David Miller <davem@...emloft.net>,
	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	netdev@...r.kernel.org,
	Linus Lüssing <linus.luessing@....de>
Subject: [PATCH] bridge: mcast snooping, fix length check of snooped MLDv1/2

"len = ntohs(ip6h->payload_len)" does not include the length of the ipv6
header itself, which the rest of this function assumes, though.

This leads to a length check less restrictive as it should be in the
following line for one thing. For another, it very likely leads to an
integer underrun when substracting the offset and therefore to a very
high new value of 'len' due to its unsignedness. This will ultimately
lead to the pskb_trim_rcsum() practically never being called, even in
the cases where it should.

Signed-off-by: Linus Lüssing <linus.luessing@....de>
---
 net/bridge/br_multicast.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 47fae4f..3793264 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1475,7 +1475,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
 	    ip6h->payload_len == 0)
 		return 0;
 
-	len = ntohs(ip6h->payload_len);
+	len = ntohs(ip6h->payload_len) + sizeof(*ip6h);
 	if (skb->len < len)
 		return -EINVAL;
 
-- 
1.5.6.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html