Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932898AbbDUPhH (ORCPT ); Tue, 21 Apr 2015 11:37:07 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57885 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932768AbbDUPfk (ORCPT ); Tue, 21 Apr 2015 11:35:40 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Ben Hutchings , Luis Henriques Subject: [PATCH 3.16.y-ckt 144/144] tcp: Fix crash in TCP Fast Open Date: Tue, 21 Apr 2015 16:32:09 +0100 Message-Id: <1429630329-21748-145-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> References: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1843 Lines: 46 3.16.7-ckt10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' skb rather than using skb_copy_expand(). The open-coded copy does not cover the skb_shared_info::gso_segs field, so in the new skb it is left set to 0. When this commit was backported into stable branches between 3.10.y and 3.16.7-ckty inclusive, it triggered the BUG() in tcp_transmit_skb(). Since Linux 3.18 the GSO segment count is kept in the tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the tcp_skb_cb structure to the new skb, so mainline and newer stable branches are not affected. Set skb_shared_info::gso_segs to the correct value of 1. Signed-off-by: Ben Hutchings Acked-by: Eric Dumazet Signed-off-by: Luis Henriques --- net/ipv4/tcp_output.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index d5457e40f5be..1ea0a07ab0b5 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2992,6 +2992,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) goto fallback; syn_data->ip_summed = CHECKSUM_PARTIAL; memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); + skb_shinfo(syn_data)->gso_segs = 1; if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space), fo->data->msg_iov, 0, space))) { kfree_skb(syn_data); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/