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 DF588C61DA4 for ; Mon, 13 Mar 2023 15:20:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230089AbjCMPUw (ORCPT ); Mon, 13 Mar 2023 11:20:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229745AbjCMPUu (ORCPT ); Mon, 13 Mar 2023 11:20:50 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B4A996A9CB; Mon, 13 Mar 2023 08:20:46 -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=jjdVo n27HVaeWyXFa+2Rsj/EZI2JFX24oQ2Zjq7vPjQ=; b=eP3bEBdNCsNCFPY0XLrSk IHGlJn6GKeRmGFcPM1H1IcOmUYhCT5qoNUeBX0DuNRsESKyAGmG/v1cY3w/lwVBv BMN/e0tRqW0l3V+QbLmmgMK+J4OfUgih+VyadGKl4X99Dpw1ExZCIp4O019Op48U gn8aocpBtm2Sk8umT0bhIs= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g4-2 (Coremail) with SMTP id _____wBnXnLvPg9kF8INAA--.4430S2; Mon, 13 Mar 2023 23:19:12 +0800 (CST) From: Zheng Wang To: ezequiel@vanguardiasur.com.ar Cc: p.zabel@pengutronix.de, mchehab@kernel.org, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, hverkuil@xs4all.nl, Zheng Wang Subject: [PATCH v2] media: hantro: fix use after free bug in hantro_remove due to race condition Date: Mon, 13 Mar 2023 23:19:09 +0800 Message-Id: <20230313151909.3658925-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: _____wBnXnLvPg9kF8INAA--.4430S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7uFy5uFWUJrWktw17XrWkWFg_yoW8GrWDpF W7KFWakrWjqF47KFn7J3y09ayrCa42gF4xWrZruw13ZF9xtr9rWry0y3WUAas8JrZavFW3 ZF48Jr4rXay2vFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zi-eOJUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiGhQxU1aEEjcWiQAAsE Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In hantro_probe, vpu->watchdog_work is bound with hantro_watchdog. Then hantro_end_prepare_run may be called to start the work. If we remove the module which will call hantro_remove to make cleanup, there may be an unfinished work. The possible sequence is as follows, which will cause a typical UAF bug. Fix it by canceling the work before cleanup in hantro_remove. CPU0 CPU1 |hantro_watchdog hantro_remove | v4l2_m2m_release | kfree(m2m_dev); | | | v4l2_m2m_get_curr_priv | m2m_dev->curr_ctx //use Signed-off-by: Zheng Wang --- v2: - move the cancel-work-related code to hantro_remove suggested by Hans Verkuil --- drivers/media/platform/verisilicon/hantro_drv.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c index b0aeedae7b65..496024b21b51 100644 --- a/drivers/media/platform/verisilicon/hantro_drv.c +++ b/drivers/media/platform/verisilicon/hantro_drv.c @@ -1099,6 +1099,7 @@ static int hantro_remove(struct platform_device *pdev) v4l2_info(&vpu->v4l2_dev, "Removing %s\n", pdev->name); + cancel_delayed_work_sync(&vpu->watchdog_work); media_device_unregister(&vpu->mdev); hantro_remove_dec_func(vpu); hantro_remove_enc_func(vpu); -- 2.25.1