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=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 87A35C43444 for ; Wed, 26 Dec 2018 22:36:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D2EB218EA for ; Wed, 26 Dec 2018 22:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545863791; bh=F9eTjEcRZEUYipucY4hvRfl+XxfBvPdr0vy1VzZKW/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nBLI0kbEoW74WOnii+L1IWYJYbdZ7iXlTvVz6JTQwS/B6T4wSH644aAqaacR2+D+V R49b/GhB5SUE9qt0LvxkRuSQ3MqdFbBH1jYKTPwQbfI45/vuoYSLUAt3rlBdui1bSt /r/KvVgevD+qfmnhv40t75I3kbLhPpPLMG8+VJi4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727322AbeLZWga (ORCPT ); Wed, 26 Dec 2018 17:36:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:36370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727241AbeLZWg1 (ORCPT ); Wed, 26 Dec 2018 17:36:27 -0500 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 8D96B218E2; Wed, 26 Dec 2018 22:36:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545863787; bh=F9eTjEcRZEUYipucY4hvRfl+XxfBvPdr0vy1VzZKW/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V6FQCwDjLPuYH2nPXm4VQ4BPt0O/621zWyHHoKoksQ7202pp+f0iXxJZMMMQtB3yA d3wqG8cT4y8q7Nbo142i/l6Xftygxfn8oTKQEhK8H3F4tF0ydlbjttw6aLiT3TWcUF gqVS5uyHLZU13Q1saMzYboQySj7UAaRwWMqFnShs= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Steffen Klassert , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 18/97] xfrm: Fix NULL pointer dereference in xfrm_input when skb_dst_force clears the dst_entry. Date: Wed, 26 Dec 2018 17:34:38 -0500 Message-Id: <20181226223557.149329-18-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181226223557.149329-1-sashal@kernel.org> References: <20181226223557.149329-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steffen Klassert [ Upstream commit 0152eee6fc3b84298bb6a79961961734e8afa5b8 ] Since commit 222d7dbd258d ("net: prevent dst uses after free") skb_dst_force() might clear the dst_entry attached to the skb. The xfrm code doesn'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 case the dst_entry was cleared. We also move the skb_dst_force() to a codepath that is not used when the transformation was offloaded, because in this case we don't have a dst_entry attached to the skb. The output and forwarding path was already fixed by commit 9e1437937807 ("xfrm: Fix NULL pointer dereference when skb_dst_force clears the dst_entry.") Fixes: 222d7dbd258d ("net: prevent dst uses after free") Reported-by: Jean-Philippe Menil Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- net/xfrm/xfrm_input.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c index be3520e429c9..790b514f86b6 100644 --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -346,6 +346,12 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) skb->sp->xvec[skb->sp->len++] = x; + skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); + goto drop; + } + lock: spin_lock(&x->lock); @@ -385,7 +391,6 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) XFRM_SKB_CB(skb)->seq.input.low = seq; XFRM_SKB_CB(skb)->seq.input.hi = seq_hi; - skb_dst_force(skb); dev_hold(skb->dev); if (crypto_done) -- 2.19.1