netdev - [PATCH] ipv6: do not increment mac header when it's unset

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]

Message-Id: <20161021092825.28085-1-Jason@zx2c4.com>
Date:   Fri, 21 Oct 2016 18:28:25 +0900
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     David Miller <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>, jmorris@...ei.org,
        yoshfuji@...ux-ipv6.org, kaber@...sh.net,
        Netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, Pipacs <pageexec@...il.com>,
        Emese Revfy <re.emese@...il.com>
Cc:     "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH] ipv6: do not increment mac header when it's unset

Otherwise we'll overflow the integer. This occurs when layer 3 tunneled
packets are handed off to the IPv6 layer.

Signed-off-by: Jason A. Donenfeld <Jason@...c4.com>
---
 net/ipv6/reassembly.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index e2ea311..a943203 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -456,7 +456,8 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 	memmove(head->head + sizeof(struct frag_hdr), head->head,
 		(head->data - head->head) - sizeof(struct frag_hdr));
-	head->mac_header += sizeof(struct frag_hdr);
+	if (skb_mac_header_was_set(head))
+		head->mac_header += sizeof(struct frag_hdr);
 	head->network_header += sizeof(struct frag_hdr);
 
 	skb_reset_transport_header(head);
-- 
2.10.1