From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754792AbbCaUcX (ORCPT ); Tue, 31 Mar 2015 16:32:23 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38893 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752849AbbCaTsw (ORCPT ); Tue, 31 Mar 2015 15:48:52 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Subash Abhinov Kasiviswanathan , Eric Dumazet , "David S. Miller" , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 007/143] ping: Fix race in free in receive path Date: Tue, 31 Mar 2015 12:46:12 -0700 Message-Id: <1427831308-1854-8-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1427831308-1854-1-git-send-email-kamal@canonical.com> References: <1427831308-1854-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt18 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "subashab@codeaurora.org" [ Upstream commit fc752f1f43c1c038a2c6ae58cc739ebb5953ccb0 ] An exception is seen in ICMP ping receive path where the skb destructor sock_rfree() tries to access a freed socket. This happens because ping_rcv() releases socket reference with sock_put() and this internally frees up the socket. Later icmp_rcv() will try to free the skb and as part of this, skb destructor is called and which leads to a kernel panic as the socket is freed already in ping_rcv(). -->|exception -007|sk_mem_uncharge -007|sock_rfree -008|skb_release_head_state -009|skb_release_all -009|__kfree_skb -010|kfree_skb -011|icmp_rcv -012|ip_local_deliver_finish Fix this incorrect free by cloning this skb and processing this cloned skb instead. This patch was suggested by Eric Dumazet Signed-off-by: Subash Abhinov Kasiviswanathan Cc: Eric Dumazet Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/ipv4/ping.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 8e0f65c..8bba193 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -962,8 +962,11 @@ void ping_rcv(struct sk_buff *skb) sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id)); if (sk != NULL) { + struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); + pr_debug("rcv on socket %p\n", sk); - ping_queue_rcv_skb(sk, skb_get(skb)); + if (skb2) + ping_queue_rcv_skb(sk, skb2); sock_put(sk); return; } -- 1.9.1