Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754267AbbBYC3Q (ORCPT ); Tue, 24 Feb 2015 21:29:16 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:43424 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753077AbbBYCQK (ORCPT ); Tue, 24 Feb 2015 21:16:10 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Subash Abhinov Kasiviswanathan , Eric Dumazet , "David S. Miller" Subject: [PATCH 3.10 08/16] ping: Fix race in free in receive path Date: Tue, 24 Feb 2015 18:10:00 -0800 Message-Id: <20150225020811.791310227@linuxfoundation.org> X-Mailer: git-send-email 2.3.0 In-Reply-To: <20150225020811.453644010@linuxfoundation.org> References: <20150225020811.453644010@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1960 Lines: 61 3.10-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: Greg Kroah-Hartman --- net/ipv4/ping.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -720,8 +720,11 @@ void ping_rcv(struct sk_buff *skb) sk = ping_v4_lookup(net, saddr, daddr, ntohs(icmph->un.echo.id), skb->dev->ifindex); 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; } -- 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/