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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 45B68C433DF for ; Sat, 30 May 2020 14:48:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20A212074D for ; Sat, 30 May 2020 14:48:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729095AbgE3Or7 (ORCPT ); Sat, 30 May 2020 10:47:59 -0400 Received: from zg8tmtm5lju5ljm3lje2naaa.icoremail.net ([139.59.37.164]:50672 "HELO zg8tmtm5lju5ljm3lje2naaa.icoremail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1728927AbgE3Or7 (ORCPT ); Sat, 30 May 2020 10:47:59 -0400 X-Greylist: delayed 320 seconds by postgrey-1.27 at vger.kernel.org; Sat, 30 May 2020 10:47:53 EDT Received: from oslab.tsinghua.edu.cn (unknown [166.111.139.172]) by app-3 (Coremail) with SMTP id EQQGZQCH55THcNJeTmaDAw--.25714S2; Sat, 30 May 2020 22:42:22 +0800 (CST) From: Jia-Ju Bai To: mchehab@kernel.org, sean@mess.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in debiirq() Date: Sat, 30 May 2020 22:42:08 +0800 Message-Id: <20200530144208.3220-1-baijiaju@tsinghua.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: EQQGZQCH55THcNJeTmaDAw--.25714S2 X-Coremail-Antispam: 1UD129KBjvJXoW7ZF15uF4rCF4rGrWfCrWUtwb_yoW8Jw1fpF WfKFyFvFWkGFyak3y7Z3Wq9an5Gas3KryUWrsrC34UZrZxKF48Ar4rAa18J3Z0kFZrZayS qF15Jry2gFWDAF7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkS14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVAFwVW5XwCF 04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r 18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vI r41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr 1lIxAIcVCF04k26cxKx2IYs7xG6rW3Jr0E3s1lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAI cVC2z280aVCY1x0267AKxVWUJVW8JbIYCTnIWIevJa73UjIFyTuYvjfUe_M3DUUUU X-CM-SenderInfo: xedlyxhdmxq3pvlqwxlxdovvfxof0/ Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The value av7110->debi_virt is stored in DMA memory, and it is assigned to data, and thus data[0] can be modified at any time by malicious hardware. In this case, "if (data[0] < 2)" can be passed, but then data[0] can be changed into a large number, which may cause buffer overflow when the code "av7110->ci_slot[data[0]]" is used. To fix this possible bug, data[0] is assigned to a local variable, which replaces the use of data[0]. Signed-off-by: Jia-Ju Bai --- drivers/media/pci/ttpci/av7110.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/media/pci/ttpci/av7110.c b/drivers/media/pci/ttpci/av7110.c index d0cdee1c6eb0..609d9888686a 100644 --- a/drivers/media/pci/ttpci/av7110.c +++ b/drivers/media/pci/ttpci/av7110.c @@ -406,14 +406,15 @@ static void debiirq(unsigned long cookie) case DATA_CI_GET: { u8 *data = av7110->debi_virt; + u8 data_0 = data[0]; - if ((data[0] < 2) && data[2] == 0xff) { + if ((data_0 < 2) && data[2] == 0xff) { int flags = 0; if (data[5] > 0) flags |= CA_CI_MODULE_PRESENT; if (data[5] > 5) flags |= CA_CI_MODULE_READY; - av7110->ci_slot[data[0]].flags = flags; + av7110->ci_slot[data_0].flags = flags; } else ci_get_data(&av7110->ci_rbuffer, av7110->debi_virt, -- 2.17.1