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 78E27C6FD19 for ; Mon, 13 Mar 2023 16:43:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230379AbjCMQnf (ORCPT ); Mon, 13 Mar 2023 12:43:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230025AbjCMQn2 (ORCPT ); Mon, 13 Mar 2023 12:43:28 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.215]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1BB7E1ADCB; Mon, 13 Mar 2023 09:43:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=39Xf9 ZCAokng5zx5EHKJyi5I1FpmWCObH+80VGR+3Fc=; b=LL9L3M7H5q7z1LfesmT5d Jndz0co5jyxSDfOI+ndvIM/i6L40TEpdFpRsSjU8ejx8cwNGjWBhThLin4sWgGm3 1WWO/gQcro/fPCU/u3xDhdlykezjStMlT5r4b6+X+IxgMi+MTyv+0Iro70ipT8NM 7OkpwqCRIGd97RIVoFlBdo= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g3-0 (Coremail) with SMTP id _____wDn7yNtUg9kfkYUAA--.18807S2; Tue, 14 Mar 2023 00:42:21 +0800 (CST) From: Zheng Wang To: ezequiel@vanguardiasur.com.ar Cc: hverkuil@xs4all.nl, mchehab@kernel.org, gregkh@linuxfoundation.org, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, Zheng Wang Subject: [PATCH v2] media: rkvdec: fix use after free bug in rkvdec_remove Date: Tue, 14 Mar 2023 00:42:20 +0800 Message-Id: <20230313164220.3753961-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: _____wDn7yNtUg9kfkYUAA--.18807S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Cw4kWFWrZF4rKr45ury8Krg_yoW8Gw4Upr W3ta45Cay5JF4UKFnrtr4xZa4rGryUKFykKr9rXa43ZryfJFnrJ3sYyF1UCFWxXrZ3Z3y3 CFyYqw1rXw4qyrDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziID73UUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiXA8xU1Xl56P-uQAAsD Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In rkvdec_probe, rkvdec->watchdog_work is bound with rkvdec_watchdog_func. Then rkvdec_vp9_run may be called to start the work. If we remove the module which will call rkvdec_remove to make cleanup, there may be a unfinished work. The possible sequence is as follows, which will cause a typical UAF bug. Fix it by canceling the work before cleanup in rkvdec_remove. CPU0 CPU1 |rkvdec_watchdog_func rkvdec_remove | rkvdec_v4l2_cleanup| v4l2_m2m_release | kfree(m2m_dev); | | | v4l2_m2m_get_curr_priv | m2m_dev->curr_ctx //use Fixes: cd33c830448b ("media: rkvdec: Add the rkvdec driver") Signed-off-by: Zheng Wang --- v2: - use cancel_delayed_work_sync instead of cancel_delayed_work suggested Hans Verkuil --- drivers/staging/media/rkvdec/rkvdec.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/media/rkvdec/rkvdec.c b/drivers/staging/media/rkvdec/rkvdec.c index 7bab7586918c..82806f198074 100644 --- a/drivers/staging/media/rkvdec/rkvdec.c +++ b/drivers/staging/media/rkvdec/rkvdec.c @@ -1066,6 +1066,8 @@ static int rkvdec_remove(struct platform_device *pdev) { struct rkvdec_dev *rkvdec = platform_get_drvdata(pdev); + cancel_delayed_work_sync(&rkvdec->watchdog_work); + rkvdec_v4l2_cleanup(rkvdec); pm_runtime_disable(&pdev->dev); pm_runtime_dont_use_autosuspend(&pdev->dev); -- 2.25.1