From patchwork Thu Apr 13 03:44:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Wang X-Patchwork-Id: 674383 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 2149AC77B6C for ; Thu, 13 Apr 2023 03:44:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229484AbjDMDot (ORCPT ); Wed, 12 Apr 2023 23:44:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229742AbjDMDoq (ORCPT ); Wed, 12 Apr 2023 23:44:46 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.216]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 73F824EE5; Wed, 12 Apr 2023 20:44:42 -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=H3yhF Avyem7KDnFlCyJY7TE1lpzbuiAFzAh4R+WP3vc=; b=OmXjSMzZAcLSWJjrO0K6n 99GE4FRsIuCiQcmAwg5q0ppzOqfKJaGZ36k8ayMHG6DiAjoHaGQvBw7I6anqHlYw aPAnaz0HLbEgLqekAdBYYHlTkmEtpYP7CZgDEzLmnibMr5b8RU9g5hzJLHEfx65b 560AvmpQXT0927I3B3CPYo= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g1-2 (Coremail) with SMTP id _____wCXt2eGejdkzWFfBQ--.36620S2; Thu, 13 Apr 2023 11:44:06 +0800 (CST) From: Zheng Wang To: mchehab@kernel.org Cc: laurent.pinchart@ideasonboard.com, sakari.ailus@linux.intel.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, alex000young@gmail.com, hackerzheng666@gmail.com, security@kernel.org, hdanton@sina.com, Zheng Wang Subject: [RESEND PATCH v2] media: bttv: fix use after free error due to btv->timeout timer Date: Thu, 13 Apr 2023 11:44:05 +0800 Message-Id: <20230413034405.36037-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: _____wCXt2eGejdkzWFfBQ--.36620S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7ZFy7GF43Zr1xXFykur43Awb_yoW8Jw1kpa ySka43CFy8Xr4UtFyUAF4kZFy3A398XrWFg34xG3ZavF4fZF92vF4jyFWqvF17XF92qrya qa4Fqr13J3WkCFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zinjjPUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/xtbBzgFQU2I0Yp2FlgABs3 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org There may be some a race condition between timer function bttv_irq_timeout and bttv_remove. The timer is setup in probe and there is no timer_delete operation in remove function. When it hit kfree btv, the function might still be invoked, which will cause use after free bug. This bug is found by static analysis, it may be false positive. Fix it by adding del_timer_sync invoking to the remove function. cpu0 cpu1 bttv_probe ->timer_setup ->bttv_set_dma ->mod_timer; bttv_remove ->kfree(btv); ->bttv_irq_timeout ->USE btv Signed-off-by: Zheng Wang --- v2: - stop replacing del_timer with del_timer_sync suggested by Hillf Danton --- drivers/media/pci/bt8xx/bttv-driver.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c index d40b537f4e98..24ba5729969d 100644 --- a/drivers/media/pci/bt8xx/bttv-driver.c +++ b/drivers/media/pci/bt8xx/bttv-driver.c @@ -4248,6 +4248,7 @@ static void bttv_remove(struct pci_dev *pci_dev) /* free resources */ free_irq(btv->c.pci->irq,btv); + del_timer_sync(&btv->timeout); iounmap(btv->bt848_mmio); release_mem_region(pci_resource_start(btv->c.pci,0), pci_resource_len(btv->c.pci,0));