From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3568CC3A59B for ; Mon, 19 Aug 2019 07:53:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 09D172085A for ; Mon, 19 Aug 2019 07:53:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PbjmwXxd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726828AbfHSHxr (ORCPT ); Mon, 19 Aug 2019 03:53:47 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:45383 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725790AbfHSHxq (ORCPT ); Mon, 19 Aug 2019 03:53:46 -0400 Received: by mail-pf1-f194.google.com with SMTP id w26so684987pfq.12 for ; Mon, 19 Aug 2019 00:53:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=TOxyTkeyWvW+Z2XuIQq2B6PeWCL2xAMUFAYSPLfMCkU=; b=PbjmwXxdRImOQGlF3VL7U1mVbhFggCNWKITSF3dfTPkTUHiKkidivHGAS15lEfBGcd Ghgv/2uZIAkMLye0sBwahET/nA3fu7vjfY9IKEBJfM4e4wyqXRA/hQo5rz1uNCgJtj7S iyoraEKsaCIxJC0mHHqc8RBau71RgMZEK7+/WkgZYQnxGg6FztzeNxmnDd5tKwRvllTp zfmweHFx7B7YvB72FtSL5P+iIESCljbfNOzvlsf03rMLu+cYl5W1iSNyGbZ1nGvXwt5T pHlEqXg0DOuA8I90wrk7Q61E2JOkEAMBLRud4UvjjtS0F/yRcBdyT6vznwygo5cUEfBg m0dA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=TOxyTkeyWvW+Z2XuIQq2B6PeWCL2xAMUFAYSPLfMCkU=; b=oIkrMmDli6/ebGmJLJxxNj+tBZXnfWmVla5QA+ZrrytAMaEddKkOtTq4Qtt0I65Lgz Q2LgAzBFF/lum6FD/2qslhZfZXabj3wGygb7XcL3to8Lbx0BPDohgpPLXHUN4ldYBMYU 5LP85Xpt48Bv23z9WwOjJcv4aPGjMGXJz/g5LDMrxn/JLJ+buXL6VQRdetw8i9jk8AjX l/DkmIuGcpuvBFAOgXbKfH04ShI29/Ow5/1OyOrNx5ygOWU/Ojo70bza6VhiFeZjcrqD UbdWDYhG1mvvP+8YX4sN7MYr1jSOWyb1C6ai5KwJ93tPWjX99TmVK7IgZme83Db83CK4 CDzQ== X-Gm-Message-State: APjAAAXABcUtfrykLItgoGmtEdraBMTBpcWqCLM4zxMKJXjqMe2PNXRa ggCTGFOcesnS9xNBrt4kM8IG7NI9TfM= X-Google-Smtp-Source: APXvYqwN7QOEsl9uUaNS/yDWKghYWdRuC/XBUW5Ws9+nfdaz0UsameAUF7RUDuAXkINHWYN335xn4g== X-Received: by 2002:aa7:9e0a:: with SMTP id y10mr22545564pfq.93.1566201225638; Mon, 19 Aug 2019 00:53:45 -0700 (PDT) Received: from dhcp-12-139.nay.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id y188sm16941270pfb.115.2019.08.19.00.53.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Aug 2019 00:53:45 -0700 (PDT) From: Hangbin Liu To: netdev@vger.kernel.org Cc: Stefano Brivio , wenxu , Alexei Starovoitov , "David S . Miller" , Eric Dumazet , Hangbin Liu Subject: [PATCH 1/2] ipv4/icmp: fix rt dst dev null pointer dereference Date: Mon, 19 Aug 2019 15:53:26 +0800 Message-Id: <20190819075327.32412-2-liuhangbin@gmail.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20190819075327.32412-1-liuhangbin@gmail.com> References: <20190815060904.19426-1-liuhangbin@gmail.com> <20190819075327.32412-1-liuhangbin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In __icmp_send() there is a possibility that the rt->dst.dev is NULL, e,g, with tunnel collect_md mode, which will cause kernel crash. Here is what the code path looks like, for GRE: - ip6gre_tunnel_xmit - ip6gre_xmit_ipv4 - __gre6_xmit - ip6_tnl_xmit - if skb->len - t->tun_hlen - eth_hlen > mtu; return -EMSGSIZE - icmp_send - net = dev_net(rt->dst.dev); <-- here The reason is __metadata_dst_init() init dst->dev to NULL by default. We could not fix it in __metadata_dst_init() as there is no dev supplied. On the other hand, the reason we need rt->dst.dev is to get the net. So we can just get it from skb->dev, just like commit 8d9336704521 ("ipv6: make icmp6_send() robust against null skb->dev") did. Fixes: c8b34e680a09 ("ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit") Signed-off-by: Hangbin Liu --- net/ipv4/icmp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 1510e951f451..5f00c9d18b02 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -582,7 +582,10 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, if (!rt) goto out; - net = dev_net(rt->dst.dev); + + if (!skb_in->dev) + goto out; + net = dev_net(skb_in->dev); /* * Find the original header. It is expected to be valid, of course. -- 2.19.2