From 65117efb2b65ef69c1c243b63296142164d152ee Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Sun, 11 May 2014 23:01:13 +0200 Subject: [PATCH] ipv6: fix calculation of option len in ip6_append_data [ 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(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 264a984..a62b610 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1229,7 +1229,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 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; -- 2.7.4