From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 18528FBEE for ; Mon, 15 May 2023 16:39:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D8A4C4339E; Mon, 15 May 2023 16:39:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684168778; bh=B3DNZ4uP3qz5Muc0Eq10wvdq5oUeHd+9JbGPh8ZKKFA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0hxbpHL3IKw1uNvx8AI6/iIg3IbdaZ+Mph2ei+w9MZrApoFwSoa7j0F9B1Uvt+dNH tcO05nrzUz7zTliKE8YEpcJv0dJ5gRcANIrYbK4Pa9ZQdpOWqBj5/vyHYlPB7I6LaV yUTLIQxMemw+9QRL62wpExOiydvFemPykSlk4io8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zheng Wang , Hans Verkuil , Sasha Levin Subject: [PATCH 4.19 039/191] media: saa7134: fix use after free bug in saa7134_finidev due to race condition Date: Mon, 15 May 2023 18:24:36 +0200 Message-Id: <20230515161708.602887921@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161707.203549282@linuxfoundation.org> References: <20230515161707.203549282@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Zheng Wang [ Upstream commit 30cf57da176cca80f11df0d9b7f71581fe601389 ] 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 Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin --- 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 2be703617e294..e7adcd4f99623 100644 --- a/drivers/media/pci/saa7134/saa7134-ts.c +++ b/drivers/media/pci/saa7134/saa7134-ts.c @@ -309,6 +309,7 @@ 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 57bea543c39ba..559db500b19ce 100644 --- a/drivers/media/pci/saa7134/saa7134-vbi.c +++ b/drivers/media/pci/saa7134/saa7134-vbi.c @@ -194,6 +194,7 @@ 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 079219288af7b..90255ecb08ca4 100644 --- a/drivers/media/pci/saa7134/saa7134-video.c +++ b/drivers/media/pci/saa7134/saa7134-video.c @@ -2213,6 +2213,7 @@ 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 */ vb2_queue_release(&dev->video_vbq); saa7134_pgtable_free(dev->pci, &dev->video_q.pt); -- 2.39.2