From: "Linus Lüssing" <linus.luessing@c0d3.blue>
To: netdev@vger.kernel.org
Cc: "Roopa Prabhu" <roopa@cumulusnetworks.com>,
"Nikolay Aleksandrov" <nikolay@cumulusnetworks.com>,
"Martin Weinelt" <martin@linuxlounge.net>,
"David S . Miller" <davem@davemloft.net>,
bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
"Linus Lüssing" <linus.luessing@c0d3.blue>
Subject: [PATCH net v2] bridge: mcast: Fix MLD2 Report IPv6 payload length check
Date: Sun, 5 Jul 2020 21:10:17 +0200 [thread overview]
Message-ID: <20200705191017.10546-1-linus.luessing@c0d3.blue> (raw)
Commit e57f61858b7c ("net: bridge: mcast: fix stale nsrcs pointer in
igmp3/mld2 report handling") introduced a bug in the IPv6 header payload
length check which would potentially lead to rejecting a valid MLD2 Report:
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")
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
Changelog v2:
* updated commit message, the issue is accidentally rejcting a valid and
not accepting an invalid MLD2 Report
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);
--
2.27.0
next reply other threads:[~2020-07-05 19:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-05 19:10 Linus Lüssing [this message]
2020-07-07 22:39 ` [PATCH net v2] bridge: mcast: Fix MLD2 Report IPv6 payload length check David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200705191017.10546-1-linus.luessing@c0d3.blue \
--to=linus.luessing@c0d3.blue \
--cc=bridge@lists.linux-foundation.org \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=martin@linuxlounge.net \
--cc=netdev@vger.kernel.org \
--cc=nikolay@cumulusnetworks.com \
--cc=roopa@cumulusnetworks.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).