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 00E68C32771 for ; Wed, 22 Jan 2020 23:42:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB7F821835 for ; Wed, 22 Jan 2020 23:42:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="d3UvMFJw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726026AbgAVXmd (ORCPT ); Wed, 22 Jan 2020 18:42:33 -0500 Received: from mail-pj1-f68.google.com ([209.85.216.68]:36653 "EHLO mail-pj1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725911AbgAVXmc (ORCPT ); Wed, 22 Jan 2020 18:42:32 -0500 Received: by mail-pj1-f68.google.com with SMTP id n59so313940pjb.1 for ; Wed, 22 Jan 2020 15:42:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=JRm1capTgZQGh1d9fhFaNGFYKROBRUsvaby6BKtEmWQ=; b=d3UvMFJwHrqo8cymGybBWeh46XGRf5PCYZfBi/3ksl1legpV5v20TWVNDhwfIUBBDT bSG87Xn0UFkcZqy0ToI7IvKUK3ckbAZCclL6riEDQ98/z625YYHp+pTwHX09/Wi5NfSF cZG+nMPuDNqqNSCtimIu0jZ5neMm5Wj4tuVawdQ5x2kzFBVetaPbuTIzp9w8XBF4sUeo DVmgdV8htHv9sRAkA1nq4y7rTgot8mKcY0h0oIHgQQ8/ClGk0S/S0owbQBhTMeHeBr2k 1usDKD8hCAbpwplTAaIEtwx0ROoL2uBCWPVpjiZ+qG11ei+yEr2JNvkc2zgrzZNII3og DlsQ== 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:mime-version :content-transfer-encoding; bh=JRm1capTgZQGh1d9fhFaNGFYKROBRUsvaby6BKtEmWQ=; b=uCi0tX+1l5EaseYTIVNx+QFN/e0yztAGVbIydpoDPnBkEIYwknOOETh/+YbtHCjIMW 7pX5KftO27ykSP/ln9q6M23OiAa7iHWa5ORLFQjQgbLFB0D+6oBrOfHJlhIwR7pbS0m2 kLYA5pMijPlm//obP+EbRcELLGPqShaR99I6/Kkc+RFBaP42Sj0htVV9VTJQZYw03tvP L3GHTpeEPddgRoJ7938epvSrtv9TsQDuVINz0cEYeBOw4tz+YORxzay4CjX5zUpFTq6r wPUiV2AtaqtNqHLgkY94sE9Pf7ZknGOlpjGzPvluWtMViEZKrMeUWLheElFieYFwYL4t +S0A== X-Gm-Message-State: APjAAAXgO0N8vQol3ue6/mGvF6k4y7/YlX8MUKNy5F7POsoVaeryDLz1 rqGHuTq8ASgQ0mWh2aonccn+EXdxRmY= X-Google-Smtp-Source: APXvYqwSUTWYc0/h86V5pYOpqI5JOtdN/DQQg5SOeHs8WxEu07JQ95hT2vq2auR2hlubwyjOXDQ/iQ== X-Received: by 2002:a17:90a:ac0f:: with SMTP id o15mr1079461pjq.133.1579736551684; Wed, 22 Jan 2020 15:42:31 -0800 (PST) Received: from tw-172-25-31-76.office.twttr.net ([8.25.197.24]) by smtp.gmail.com with ESMTPSA id h6sm36576pfo.175.2020.01.22.15.42.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jan 2020 15:42:31 -0800 (PST) From: Cong Wang To: netdev@vger.kernel.org Cc: Cong Wang , syzbot+5af9a90dad568aa9f611@syzkaller.appspotmail.com, syzbot+2f07903a5b05e7f36410@syzkaller.appspotmail.com, Eric Dumazet Subject: [Patch net] net_sched: fix datalen for ematch Date: Wed, 22 Jan 2020 15:42:02 -0800 Message-Id: <20200122234203.15441-1-xiyou.wangcong@gmail.com> X-Mailer: git-send-email 2.21.1 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 syzbot reported an out-of-bound access in em_nbyte. As initially analyzed by Eric, this is because em_nbyte sets its own em->datalen in em_nbyte_change() other than the one specified by user, but this value gets overwritten later by its caller tcf_em_validate(). We should leave em->datalen untouched to respect their choices. I audit all the in-tree ematch users, all of those implement ->change() set em->datalen, so we can just avoid setting it twice in this case. Reported-and-tested-by: syzbot+5af9a90dad568aa9f611@syzkaller.appspotmail.com Reported-by: syzbot+2f07903a5b05e7f36410@syzkaller.appspotmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: Eric Dumazet Signed-off-by: Cong Wang --- net/sched/ematch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/ematch.c b/net/sched/ematch.c index 8f2ad706784d..d0140a92694a 100644 --- a/net/sched/ematch.c +++ b/net/sched/ematch.c @@ -263,12 +263,12 @@ static int tcf_em_validate(struct tcf_proto *tp, } em->data = (unsigned long) v; } + em->datalen = data_len; } } em->matchid = em_hdr->matchid; em->flags = em_hdr->flags; - em->datalen = data_len; em->net = net; err = 0; -- 2.21.1