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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no 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 1ACA4C433DB for ; Sun, 21 Feb 2021 12:40:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D578164EF2 for ; Sun, 21 Feb 2021 12:40:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229907AbhBUMkB (ORCPT ); Sun, 21 Feb 2021 07:40:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229802AbhBUMj6 (ORCPT ); Sun, 21 Feb 2021 07:39:58 -0500 Received: from mail-lj1-x22d.google.com (mail-lj1-x22d.google.com [IPv6:2a00:1450:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C18AC061574; Sun, 21 Feb 2021 04:39:18 -0800 (PST) Received: by mail-lj1-x22d.google.com with SMTP id e17so47639223ljl.8; Sun, 21 Feb 2021 04:39:17 -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:in-reply-to:references :mime-version:content-transfer-encoding; bh=7ooJNNgyLxSgtXrlAqytg6PlPTL1gBhKSaEdENZ44wU=; b=B9acX6iN9eqTg0mLidcuyzgxYnKymlJcyVcHlXprYUxUdun9xANNEUVJzWCo6Gw2TT UgFi8r6TfNB0mAy/nc5xs18oEocRa4sCUrdafDQ02jlCl6ey1zdTVhE/VeCn+OSlZbhh JhyylCgudNf2/NhRWgAV6p/8fvwt+xGhUMtAfmXCsI0iRoXF19g4iZhY49vagUnpHqx6 aqe9AZMTQq6fuU8qDp3ST1G0ERcVuZ/2yZ7rV0c8t8ddkO/Jg1OYE3VxlBtrSq1lE3NR XmickdD8eEndQ2FRontRHjExiDWPTxxLpcCaggaVu/nqPY9t1rIvushie5hEzPj0KX9L s1Gw== 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=7ooJNNgyLxSgtXrlAqytg6PlPTL1gBhKSaEdENZ44wU=; b=EytUB+0DnpXQpw5saWtHU4vbBE+vaHILnNpSl8TWv6mNItOdJXmUWnA+wY39VEVWsR BX4gP4wLvfGHqerTrlaucxtuSejRQnGLnioTyOMCbcO3YKPoy5ywpS6e8TQurWN1eIAb itm5XLStr58uE3p2iIArwmTkoedHG22vSpTFiecFhvIqrKPgyqntQbKXsKK1saoq0Pv5 xmkAhmVBQsnK0WNYQmjlcfh9i4r4/liwWJwJz+Y+viGUifny9WbxrKzVrG2UH79s+tyY 2+u3SH6L0aBNZ6Fb/O+Vgrr3W7Bz624HovHejY+SMOKhAct9eYFmpaRm5+DfsqNhEczC aRxQ== X-Gm-Message-State: AOAM530A5kxH4T7LBrPdi4p1Tf1nKfQuqHS9PBpQsNVF4gVFbfDnV6qH mhTOR+gzGtbs4iiCfJI3zHg= X-Google-Smtp-Source: ABdhPJwKhyoWxWMqQrvDAxezIvfKgkgDz8xjxAZSo7ShaWjCfzZqXVvk1ISVEoLcC84Tm23Gd9hQBA== X-Received: by 2002:a2e:a404:: with SMTP id p4mr5629250ljn.286.1613911156434; Sun, 21 Feb 2021 04:39:16 -0800 (PST) Received: from localhost.localdomain ([37.150.90.70]) by smtp.googlemail.com with ESMTPSA id b14sm1677559lji.120.2021.02.21.04.39.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Feb 2021 04:39:15 -0800 (PST) From: Sabyrzhan Tasbolatov To: eric.dumazet@gmail.com Cc: davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, snovitoll@gmail.com, syzbot+c2a7e5c5211605a90865@syzkaller.appspotmail.com Subject: Re: [PATCH] net/qrtr: restrict length in qrtr_tun_write_iter() Date: Sun, 21 Feb 2021 18:39:12 +0600 Message-Id: <20210221123912.3185059-1-snovitoll@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <3b27dac1-45b9-15ad-c25e-2f5f3050907e@gmail.com> References: <3b27dac1-45b9-15ad-c25e-2f5f3050907e@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Do we really expect to accept huge lengths here ? Sorry for late response but I couldnt find any reference to the max length of incoming data for qrtr TUN interface. > qrtr_endpoint_post() will later attempt a netdev_alloc_skb() which will need > some extra space (for struct skb_shared_info) Thanks, you're right, qrtr_endpoint_post() will alloc another slab buffer. We can check the length of skb allocation but we need to do following: int qrtr_endpoint_post(.., const void *data, size_t len) { .. when QRTR_PROTO_VER_1: hdrlen = sizeof(*data); when QRTR_PROTO_VER_2: hdrlen = sizeof(*data) + data->optlen; len = (KMALLOC_MAX_SIZE - hdrlen) % data->size; skb = netdev_alloc_skb(NULL, len); .. skb_put_data(skb, data + hdrlen, size); So it requires refactoring as in qrtr_tun_write_iter() we just allocate and pass it to qrtr_endpoint_post() and there we need to do len calculation as above *before* netdev_alloc_skb(NULL, len). Perhaps there is a nicer solution though.