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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Sun,  5 Jul 2020 20:22:34 +0200
From:   Linus Lüssing <>
Cc:     Roopa Prabhu <>,
        Nikolay Aleksandrov <>,
        Martin Weinelt <>,
        "David S . Miller" <>,,,
        Linus Lüssing <>
Subject: [PATCH net] bridge: mcast: Fix MLD2 Report IPv6 payload length check

Commit e57f61858b7c ("net: bridge: mcast: fix stale nsrcs pointer in
igmp3/mld2 report handling") introduced a small bug which would potentially
lead to accepting an MLD2 Report with a broken IPv6 header payload length

The check needs to take into account the 2 bytes for the "Number of
Sources" field in the "Multicast Address Record" before reading it.
And not the size of a pointer to this field.

Fixes: e57f61858b7c ("net: bridge: mcast: fix stale nsrcs pointer in igmp3/mld2 report handling")
Signed-off-by: Linus Lüssing <>
 net/bridge/br_multicast.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 83490bf73a13..4c4a93abde68 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1000,21 +1000,21 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br,
 	num = ntohs(icmp6h->icmp6_dataun.un_data16[1]);
 	len = skb_transport_offset(skb) + sizeof(*icmp6h);
 	for (i = 0; i < num; i++) {
 		__be16 *_nsrcs, __nsrcs;
 		u16 nsrcs;
 		nsrcs_offset = len + offsetof(struct mld2_grec, grec_nsrcs);
 		if (skb_transport_offset(skb) + ipv6_transport_len(skb) <
-		    nsrcs_offset + sizeof(_nsrcs))
+		    nsrcs_offset + sizeof(__nsrcs))
 			return -EINVAL;
 		_nsrcs = skb_header_pointer(skb, nsrcs_offset,
 					    sizeof(__nsrcs), &__nsrcs);
 		if (!_nsrcs)
 			return -EINVAL;
 		nsrcs = ntohs(*_nsrcs);
 		grec_len = struct_size(grec, grec_src, nsrcs);

Powered by blists - more mailing lists