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[2620:137:e000::1:20]) by mx.google.com with ESMTP id co6-20020a17090afe8600b002309f0bd759si10021388pjb.92.2023.03.18.01.54.31; Sat, 18 Mar 2023 01:54:45 -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=Hxi1LaVS; 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 S229697AbjCRIvI (ORCPT + 99 others); Sat, 18 Mar 2023 04:51:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229473AbjCRIvG (ORCPT ); Sat, 18 Mar 2023 04:51:06 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.215]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5FA3738B71; Sat, 18 Mar 2023 01:51:00 -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=e2K1s tAkZBMfErG++SlUbeC1nvxtK/csvq7dYD3khQM=; b=Hxi1LaVS7kkXBX976oXwz lsAa8grThqsAxqUd4OYG2nAnEsrz6Ls380AAlXWuiXQ3W9nD1hDa+FboyhjxEyFv jp2iXh+Wdn+hXuuMHxfw5dyO1BYtIDbZ7GCmx0gng0XfZBlTD60itjQL4aI9QeeY aKKdJUaH3sG0pES1qQeoBk= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g4-0 (Coremail) with SMTP id _____wBnb8dQexVkv0urAQ--.15549S2; Sat, 18 Mar 2023 16:50:25 +0800 (CST) From: Zheng Wang To: mchehab@kernel.org Cc: hverkuil-cisco@xs4all.nl, tasos@tasossah.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, Zheng Wang Subject: [PATCH] media: saa7134: fix use after free bug in saa7134_finidev due to race condition Date: Sat, 18 Mar 2023 16:50:23 +0800 Message-Id: <20230318085023.832510-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: _____wBnb8dQexVkv0urAQ--.15549S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxCFy5Zr1xAw4fWrW5Aw4fKrg_yoW5GF4DpF WUtF93Aw1UJr4UJa1xXa1UCFySgrZ5XFy3Wasru34Fgr15Gay8Jr1Yq34UKF9xJrsrZa43 Kr18urnrJrykuaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziaiiDUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiGhc2U1aEEnbMxwAAsV 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?1760695089507044984?= X-GMAIL-MSGID: =?utf-8?q?1760695089507044984?= In saa7134_initdev, it will call saa7134_hwinit1. There are three function invoking here: saa7134_video_init1, saa7134_ts_init1 and saa7134_vbi_init1. All of them will init a timer with same function. Take saa7134_video_init1 as an example. It'll bound &dev->video_q.timeout with saa7134_buffer_timeout. In buffer_activate, the timer funtcion is started. If we remove the module or device which will call saa7134_finidev 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 timer works accordingly before cleanup in saa7134_finidev. CPU0 CPU1 |saa7134_buffer_timeout saa7134_finidev | kfree(dev); | | | saa7134_buffer_next | //use dev Fixes: 1e7126b4a86a ("media: saa7134: Convert timers to use timer_setup()") Signed-off-by: Zheng Wang --- drivers/media/pci/saa7134/saa7134-ts.c | 1 + drivers/media/pci/saa7134/saa7134-vbi.c | 1 + drivers/media/pci/saa7134/saa7134-video.c | 1 + 3 files changed, 3 insertions(+) diff --git a/drivers/media/pci/saa7134/saa7134-ts.c b/drivers/media/pci/saa7134/saa7134-ts.c index 6a5053126237..437dbe5e75e2 100644 --- a/drivers/media/pci/saa7134/saa7134-ts.c +++ b/drivers/media/pci/saa7134/saa7134-ts.c @@ -300,6 +300,7 @@ int saa7134_ts_start(struct saa7134_dev *dev) int saa7134_ts_fini(struct saa7134_dev *dev) { + del_timer_sync(&dev->ts_q.timeout); saa7134_pgtable_free(dev->pci, &dev->ts_q.pt); return 0; } diff --git a/drivers/media/pci/saa7134/saa7134-vbi.c b/drivers/media/pci/saa7134/saa7134-vbi.c index 3f0b0933eed6..3e773690468b 100644 --- a/drivers/media/pci/saa7134/saa7134-vbi.c +++ b/drivers/media/pci/saa7134/saa7134-vbi.c @@ -185,6 +185,7 @@ int saa7134_vbi_init1(struct saa7134_dev *dev) int saa7134_vbi_fini(struct saa7134_dev *dev) { /* nothing */ + del_timer_sync(&dev->vbi_q.timeout); return 0; } diff --git a/drivers/media/pci/saa7134/saa7134-video.c b/drivers/media/pci/saa7134/saa7134-video.c index 4d8974c9fcc9..29124756a62b 100644 --- a/drivers/media/pci/saa7134/saa7134-video.c +++ b/drivers/media/pci/saa7134/saa7134-video.c @@ -2146,6 +2146,7 @@ int saa7134_video_init1(struct saa7134_dev *dev) void saa7134_video_fini(struct saa7134_dev *dev) { + del_timer_sync(&dev->video_q.timeout); /* free stuff */ saa7134_pgtable_free(dev->pci, &dev->video_q.pt); saa7134_pgtable_free(dev->pci, &dev->vbi_q.pt);