From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Preobrazhensky , Hannes Frederic Sowa , "David S. Miller" Subject: [PATCH 3.14 127/140] ipv6: fix calculation of option len in ip6_append_data Date: Wed, 28 May 2014 21:34:26 -0700 Message-Id: <20140529043105.694886641@linuxfoundation.org> In-Reply-To: <20140529043049.661315084@linuxfoundation.org> References: <20140529043049.661315084@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hannes Frederic Sowa [ Upstream commit 3a1cebe7e05027a1c96f2fc1a8eddf5f19b78f42 ] tot_len does specify the size of struct ipv6_txoptions. We need opt_flen + opt_nflen to calculate the overall length of additional ipv6 extensions. I found this while auditing the ipv6 output path for a memory corruption reported by Alexey Preobrazhensky while he fuzzed an instrumented AddressSanitizer kernel with trinity. This may or may not be the cause of the original bug. Fixes: 4df98e76cde7c6 ("ipv6: pmtudisc setting not respected with UFO/CORK") Reported-by: Alexey Preobrazhensky Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1229,7 +1229,7 @@ int ip6_append_data(struct sock *sk, int unsigned int maxnonfragsize, headersize; headersize = sizeof(struct ipv6hdr) + - (opt ? opt->tot_len : 0) + + (opt ? opt->opt_flen + opt->opt_nflen : 0) + (dst_allfrag(&rt->dst) ? sizeof(struct frag_hdr) : 0) + rt->rt6i_nfheader_len;