From patchwork Thu Mar 4 15:24:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 394126 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10C70C4361B for ; Thu, 4 Mar 2021 15:27:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED14364FD3 for ; Thu, 4 Mar 2021 15:27:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234804AbhCDP0s (ORCPT ); Thu, 4 Mar 2021 10:26:48 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:62431 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234737AbhCDP0j (ORCPT ); Thu, 4 Mar 2021 10:26:39 -0500 Received: from fsav302.sakura.ne.jp (fsav302.sakura.ne.jp [153.120.85.133]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 124FP2Er030912; Fri, 5 Mar 2021 00:25:02 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav302.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav302.sakura.ne.jp); Fri, 05 Mar 2021 00:25:02 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav302.sakura.ne.jp) Received: from localhost.localdomain (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 124FOtn4030882 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 5 Mar 2021 00:25:02 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) From: Tetsuo Handa To: Valentina Manea , Shuah Khan , Greg Kroah-Hartman Cc: Arnd Bergmann , linux-usb@vger.kernel.org, Tetsuo Handa Subject: [PATCH v4 04/12] usb: usbip: stub: serialize usbip_sockfd_store() against event_handler() Date: Fri, 5 Mar 2021 00:24:47 +0900 Message-Id: <20210304152455.3685-5-penguin-kernel@I-love.SAKURA.ne.jp> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20210304152455.3685-1-penguin-kernel@I-love.SAKURA.ne.jp> References: <20210304152455.3685-1-penguin-kernel@I-love.SAKURA.ne.jp> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org usbip_sockfd_store() must perform if (sdev->ud.status != SDEV_ST_AVAILABLE) { /* misc assignments for attach operation */ sdev->ud.status = SDEV_ST_USED; } under a lock, or multiple ud->tcp_{tx,rx} are created (which will later cause a crash like [1]) and refcount on ud->tcp_socket is leaked when usbip_sockfd_store() is concurrently called. Since I don't want to replace "return" with "goto" in order to call usbip_event_unlock(), wrap whole function in order to keep changes minimal. [1] https://syzkaller.appspot.com/bug?extid=95ce4b142579611ef0a9 Reported-by: syzbot Tested-by: syzbot Signed-off-by: Tetsuo Handa --- drivers/usb/usbip/stub_dev.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c index 2305d425e6c9..cea5663d1994 100644 --- a/drivers/usb/usbip/stub_dev.c +++ b/drivers/usb/usbip/stub_dev.c @@ -39,8 +39,8 @@ static DEVICE_ATTR_RO(usbip_status); * is used to transfer usbip requests by kernel threads. -1 is a magic number * by which usbip connection is finished. */ -static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) +static ssize_t __usbip_sockfd_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) { struct stub_device *sdev = dev_get_drvdata(dev); int sockfd = 0; @@ -104,6 +104,17 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a spin_unlock_irq(&sdev->ud.lock); return -EINVAL; } +static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + ssize_t ret = usbip_event_lock_killable(); + + if (ret) + return ret; + ret = __usbip_sockfd_store(dev, attr, buf, count); + usbip_event_unlock(); + return ret; +} static DEVICE_ATTR_WO(usbip_sockfd); static struct attribute *usbip_attrs[] = {