From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jason A. Donenfeld" Subject: [PATCH] ipv6: do not increment mac header when it's unset Date: Fri, 21 Oct 2016 18:28:25 +0900 Message-ID: <20161021092825.28085-1-Jason@zx2c4.com> References: Cc: "Jason A. Donenfeld" To: David Miller , Alexey Kuznetsov , jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, Netdev , LKML , Pipacs , Emese Revfy Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 --- 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