From patchwork Thu Jul 14 06:09:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: shaozhengchao X-Patchwork-Id: 12917326 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1632C43334 for ; Thu, 14 Jul 2022 06:05:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232248AbiGNGFs (ORCPT ); Thu, 14 Jul 2022 02:05:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230061AbiGNGFq (ORCPT ); Thu, 14 Jul 2022 02:05:46 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D7A42F001; Wed, 13 Jul 2022 23:05:44 -0700 (PDT) Received: from dggpeml500026.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Lk3nl0b2bzkX1F; Thu, 14 Jul 2022 14:03:23 +0800 (CST) Received: from huawei.com (10.175.101.6) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 14 Jul 2022 14:05:27 +0800 From: Zhengchao Shao To: , , , , , , , CC: , , , , , , , , , , , Subject: [PATCH v2,bpf-next] bpf: Don't redirect packets with invalid pkt_len Date: Thu, 14 Jul 2022 14:09:59 +0800 Message-ID: <20220714060959.25232-1-shaozhengchao@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500026.china.huawei.com (7.185.36.106) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Syzbot found an issue [1]: fq_codel_drop() try to drop a flow whitout any skbs, that is, the flow->head is null. The root cause, as the [2] says, is because that bpf_prog_test_run_skb() run a bpf prog which redirects empty skbs. So we should determine whether the length of the packet modified by bpf prog is valid before forwarding it directly. LINK: [1] https://syzkaller.appspot.com/bug?id=0b84da80c2917757915afa89f7738a9d16ec96c5 LINK: [2] https://www.spinics.net/lists/netdev/msg777503.html Reported-by: syzbot+7a12909485b94426aceb@syzkaller.appspotmail.com Signed-off-by: Zhengchao Shao Reviewed-by: Stanislav Fomichev --- v1: should not check len in fast path net/bpf/test_run.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 2ca96acbc50a..750d7d173a20 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -1152,6 +1152,12 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr, ret = convert___skb_to_skb(skb, ctx); if (ret) goto out; + + if (skb->len == 0) { + ret = -EINVAL; + goto out; + } + ret = bpf_test_run(prog, skb, repeat, &retval, &duration, false); if (ret) goto out;