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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 6A05FC04EBD for ; Tue, 16 Oct 2018 04:36:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F1C920866 for ; Tue, 16 Oct 2018 04:36:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Gyq03Ark" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F1C920866 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727666AbeJPMA6 (ORCPT ); Tue, 16 Oct 2018 08:00:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:47612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727553AbeJPMA5 (ORCPT ); Tue, 16 Oct 2018 08:00:57 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BC66C2098A; Tue, 16 Oct 2018 04:12:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539663155; bh=mEYU4rbwyEbGyPpbqjY480h/bv8YrxtWz9L/UTI0Ze4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gyq03Ark8wnOB7pU0eY3rRvkRLjLpKfCMf37wgD5pmG+YYfUxkqUs3XqNqBewcSg9 xDfSt3Bqw7lW7XHFheelwNqNpyQCywoPTaeNFPFWr3F4AXGd72oTHmbUZbkOVCGsHq YP9R+H79IcrjxKL1IK1EEej73m9wadmLLckHFLFA= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Steffen Klassert , Sasha Levin Subject: [PATCH AUTOSEL 4.18 011/100] xfrm: Fix NULL pointer dereference when skb_dst_force clears the dst_entry. Date: Tue, 16 Oct 2018 00:10:52 -0400 Message-Id: <20181016041221.135528-11-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181016041221.135528-1-sashal@kernel.org> References: <20181016041221.135528-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steffen Klassert [ Upstream commit 9e1437937807b0122e8da1ca8765be2adca9aee6 ] Since commit 222d7dbd258d ("net: prevent dst uses after free") skb_dst_force() might clear the dst_entry attached to the skb. The xfrm code don't expect this to happen, so we crash with a NULL pointer dereference in this case. Fix it by checking skb_dst(skb) for NULL after skb_dst_force() and drop the packet in cast the dst_entry was cleared. Fixes: 222d7dbd258d ("net: prevent dst uses after free") Reported-by: Tobias Hommel Reported-by: Kristian Evensen Reported-by: Wolfgang Walter Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- net/xfrm/xfrm_output.c | 4 ++++ net/xfrm/xfrm_policy.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c index 89b178a78dc7..36d15a38ce5e 100644 --- a/net/xfrm/xfrm_output.c +++ b/net/xfrm/xfrm_output.c @@ -101,6 +101,10 @@ static int xfrm_output_one(struct sk_buff *skb, int err) spin_unlock_bh(&x->lock); skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + goto error_nolock; + } if (xfrm_offload(skb)) { x->type_offload->encap(x, skb); diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index a94983e03a8b..526e6814ed4b 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2551,6 +2551,10 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family) } skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMFWDHDRERROR); + return 0; + } dst = xfrm_lookup(net, skb_dst(skb), &fl, NULL, XFRM_LOOKUP_QUEUE); if (IS_ERR(dst)) { -- 2.17.1