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=-4.2 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, URIBL_BLOCKED,USER_AGENT_SANE_1 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 9A03AC4338F for ; Sat, 31 Jul 2021 04:05:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75B4960EC0 for ; Sat, 31 Jul 2021 04:05:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231613AbhGaEF4 (ORCPT ); Sat, 31 Jul 2021 00:05:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229454AbhGaEFz (ORCPT ); Sat, 31 Jul 2021 00:05:55 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 052B7C06175F for ; Fri, 30 Jul 2021 21:05:49 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id k4-20020a17090a5144b02901731c776526so23571626pjm.4 for ; Fri, 30 Jul 2021 21:05:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:cc:from:subject:message-id:date:user-agent:mime-version :content-transfer-encoding:content-language; bh=VFXOOTn/Vn4wZYYve4ASVb/HHzXMtsmmCHHBTxOGsvA=; b=sLP19dreR3fqB84FUJE8d2g6cKKyeCBFloWtY579h/6SgMebVOowmEV4wiedpKaRVs cS8qMrRmvv0IwGaeuvEmNrNDVHyARI8tBPM/HjVKUo1dv9CEKmZZ8RJCWzM1VkqtrhNo Y9/q+zdJeQbJl+gcod8zZLVlnDOUC7oLOD122eRZ9gK4l5r89UeqvTP+kDL4luB0TdYA pIzBwG8ASjM9fg/Ibmx7hrr2b4BS/urcpsGYos5Aa5/VzJvR99PTU8hQueXVdZjZSQXz 3GsFeuawMS5FjY47pwATwFNmbLCBI7OZRd19gYWz5Cj6AhQmFlYngLiMBrZjNVuYoV5z rLtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:from:subject:message-id:date:user-agent :mime-version:content-transfer-encoding:content-language; bh=VFXOOTn/Vn4wZYYve4ASVb/HHzXMtsmmCHHBTxOGsvA=; b=X29ikFlNhgxxLpRebxXXEzKr+YDDesLBK1WW66ufKyhDlthXY4lt6edQYc3JYfUC+V B4xsCR70QXPSzYaU5wdf9TEM4zQtibQtZgfpSyg6WMgJY4AAqdwa5uf8T2aP+n3vlhgc lx4vOa/sXuRilyJs5bBa98YrKt67Axf1J852YC6HgeZefGaz8lsGUBCvpyM5L9a5+BPf vBHE83pdIcSltpc1AxGteyvyLkMql48P6i2eeZfNQ1z4AoxKFwNq1xAiOvD+RySmVuAH mB9yc71kX/6NS94mIQ0CeN0Ki4mMywdMQih3qotmjIH9Kc9ySu3FEIqHPvAGK14nAhYe iYGQ== X-Gm-Message-State: AOAM530uzhMl90uhYVAhQm8IkBcU/55QxgOyGDmke1dD452+xhvw6kJP m81O7PRxavKTYY6e0EXTwbM= X-Google-Smtp-Source: ABdhPJzaAo2Op1LNut0Z98WmyNuIKcEFNkrZ5JV3ZnBHASVQBzU/8t+3IAryF8kG1yC3vJT2e68O5Q== X-Received: by 2002:a62:7b86:0:b029:32b:364a:e7e4 with SMTP id w128-20020a627b860000b029032b364ae7e4mr5848448pfc.49.1627704348615; Fri, 30 Jul 2021 21:05:48 -0700 (PDT) Received: from [10.106.0.50] ([45.135.186.29]) by smtp.gmail.com with ESMTPSA id h16sm3564511pfn.215.2021.07.30.21.05.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 30 Jul 2021 21:05:48 -0700 (PDT) To: dwmw2@infradead.org, richard@nod.at Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com From: Li Tuo Subject: [BUG] jffs2: possible null-pointer dereference in jffs2_scan_dirty_space() Message-ID: Date: Sat, 31 Jul 2021 12:05:47 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Our static analysis tool finds a possible null-pointer dereference in the jffs2 driver in Linux 5.14.0-rc3: The variable jeb->last_node is checked in: 673:    if (jeb->last_node && ref_obsolete(jeb->last_node)) This indicates that jeb->last_node can be NULL. If so, the function jffs2_link_node_ref() is called with the argument jeb: 685:    jffs2_link_node_ref(c, jeb, ofs, size, NULL); In the called function, jeb->last_node is assigned to the pointer ref, which means ref is also NULL. However, the possible NULL pointer ref is dereferenced in some statements such as: 597:    dbg_noderef("Last node at %p is (%08x,%p)\n", ref, ref->flash_offset, ref->next_in_ino); 600:    while (ref->flash_offset != REF_EMPTY_NODE) I am not quite sure whether this possible null-pointer dereference is real and how to fix it if it is real. Any feedback would be appreciated, thanks! Reported-by: TOTE Robot Best wishes, Tuo Li