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[2620:137:e000::1:20]) by mx.google.com with ESMTP id t190-20020a6381c7000000b0050a1fd1a6e7si4033983pgd.737.2023.03.13.09.28.28; Mon, 13 Mar 2023 09:28:43 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@163.com header.s=s110527 header.b=c9O4uZye; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=163.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230033AbjCMPuB (ORCPT + 99 others); Mon, 13 Mar 2023 11:50:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229524AbjCMPt7 (ORCPT ); Mon, 13 Mar 2023 11:49:59 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.215]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1BC9442BCE; Mon, 13 Mar 2023 08:49:57 -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=zZIaX bZODM+Wxzq0HHWHcgsRoTtcQ0oqs1PXU9bdNqE=; b=c9O4uZyeymy4ozAsWeZ+9 tH+ZJXubx0BfuhAl/F2uSdKaNYBIXIo/Y+NHm1pgT3HIJ65McCAiNfYqMPp2Om6h 7F3oitdwkm4jYc8QdH2ad/zSELs5v12rhY0iJQKy4LCPM/tZJnl5gYQgbQusxA2X wIOpKmkTOxgEILYJLiB6ec= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g3-2 (Coremail) with SMTP id _____wAnHYLqRQ9kDrURAA--.16196S2; Mon, 13 Mar 2023 23:48:58 +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 v4] media: hantro: fix use after free bug in hantro_remove due to race condition Date: Mon, 13 Mar 2023 23:48:56 +0800 Message-Id: <20230313154856.3691660-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: _____wAnHYLqRQ9kDrURAA--.16196S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Wry3Xw4kJw47Jr4rWr4kZwb_yoW8Zw13pF W3KrW5KrWjqF47KFn7tay09ayfCasFqF4UXrZruw13AF9xtry7urySya18CF98JrZ3ZF4a qF4jqrWrZw42vFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zi-eOJUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiXA4xU1Xl56OqKgABsF X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760270665715627796?= X-GMAIL-MSGID: =?utf-8?q?1760270665715627796?= 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 close the file or remove the module which will call hantro_release and hantro_remove to make cleanup, there may be an unfinished work. The possible sequence is as follows, which will cause a typical UAF bug. The same thing will happen in hantro_release, and use ctx after freeing it. Fix it by canceling the work before cleanup in hantro_release. 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 Fixes: 932a9317ac49 ("media: hantro: Add helpers to prepare/finish a run") --- v4: - add Fixes label to help with the fix v3: - use cancel_delayed_work_sync instead of cancel_delayed_work and add it to hantro_release suggested by Hans Verkuil v2: - move the cancel-work-related code to hantro_remove suggested by Hans Verkuil --- drivers/media/platform/verisilicon/hantro_drv.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c index b0aeedae7b65..86a4c0fa8c7d 100644 --- a/drivers/media/platform/verisilicon/hantro_drv.c +++ b/drivers/media/platform/verisilicon/hantro_drv.c @@ -597,6 +597,7 @@ static int hantro_release(struct file *filp) struct hantro_ctx *ctx = container_of(filp->private_data, struct hantro_ctx, fh); + cancel_delayed_work_sync(&ctx->dev->watchdog_work); /* * No need for extra locking because this was the last reference * to this file. @@ -1099,6 +1100,7 @@ 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);