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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 C0A31C04EB9 for ; Tue, 4 Dec 2018 00:43:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60BE020834 for ; Tue, 4 Dec 2018 00:43:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="iIY1WzCk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 60BE020834 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725999AbeLDAnt (ORCPT ); Mon, 3 Dec 2018 19:43:49 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:45016 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725915AbeLDAnt (ORCPT ); Mon, 3 Dec 2018 19:43:49 -0500 Received: by mail-pg1-f196.google.com with SMTP id t13so6498339pgr.11 for ; Mon, 03 Dec 2018 16:43:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=2KQNJO8uFkDQm49FDynLRoSgm5JYnbeN3mqYf/XYMRY=; b=iIY1WzCkG7EL2UBPkpKpeI5ri9n2f/UzUpLsQlRLY3UDMThHLmja1whxyEn4ysQ6DE NJLBXTZfR7Zg/nOYVJ3IULdI95lNagbSPIsXB/ifeNeO7G2U/XsFOKdn1pTb2SStiUTj hgaKcgauhxhy5lvMUB0XLqyI+JfXtfLLCk1jo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=2KQNJO8uFkDQm49FDynLRoSgm5JYnbeN3mqYf/XYMRY=; b=hQOheSwgq7+MdC9scuS1CdS/eSXoUu+96IIC9QVQy7KR+qXNqJCI2UZF8apTb8GRQ8 4GTR2P+bY2GEaAqpSbYNagWrV/lLyoK7Jai7Yb93QHtMJgG0PaDVH1Kf7Sc7q7XTEoIK qv8H/UV2B0VOh8fZgmYD5zBiuAIrw0gdPBi8fLQbbzc9PnoAJcXbRceiy/RkH5vq5Fky x9jFTDvtfl9EvcbPlsXPco103TsB/HkurYaPpgcY+FtuNy4mIXDHs4aHpA5yuhJbwaUC PKy7s96j5GIp7i4JmW/AbMJbjXN50augoqltAK6QQTyatH87R4gV3V1sZlqf3rE3Sgkm HDig== X-Gm-Message-State: AA+aEWYUj9U3oh1CT5c/0I/dSAKULAuWH0c8Ka+tKA6CyNc+PhHJAjiD jQzd5vWYd+LusnE4Aj8g25Sg8w== X-Google-Smtp-Source: AFSGD/W/E9nCmWDZPFBVgs+3o4K5zFb9/NfpH2z1WeK+C/+Mdbm3zKm8ERTWyGJ/Ap3pbqgwS8IKbA== X-Received: by 2002:a65:60c2:: with SMTP id r2mr14030930pgv.393.1543884227492; Mon, 03 Dec 2018 16:43:47 -0800 (PST) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id z62sm21483133pfl.33.2018.12.03.16.43.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 03 Dec 2018 16:43:46 -0800 (PST) Date: Mon, 3 Dec 2018 16:43:45 -0800 From: Kees Cook To: Dan Carpenter , "Joel Fernandes (Google)" Cc: linux-kernel@vger.kernel.org Subject: [PATCH] pstore/ram: Avoid NULL deref in ftrace merging failure path Message-ID: <20181204004345.GA48115@beast> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Given corruption in the ftrace records, it might be possible to allocate tmp_prz without assigning prz to it, but still marking it as needing to be freed, which would cause at least a NULL dereference. smatch warnings: fs/pstore/ram.c:340 ramoops_pstore_read() error: we previously assumed 'prz' could be null (see line 255) https://lists.01.org/pipermail/kbuild-all/2018-December/055528.html Reported-by: Dan Carpenter Fixes: 2fbea82bbb89 ("pstore: Merge per-CPU ftrace records into one") Cc: "Joel Fernandes (Google)" Signed-off-by: Kees Cook --- fs/pstore/ram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index e6d9560ea455..96f7d32cd184 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -291,6 +291,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record) GFP_KERNEL); if (!tmp_prz) return -ENOMEM; + prz = tmp_prz; free_prz = true; while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) { @@ -309,7 +310,6 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record) goto out; } record->id = 0; - prz = tmp_prz; } } -- 2.17.1 -- Kees Cook