From mboxrd@z Thu Jan 1 00:00:00 1970 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_RED,USER_AGENT_GIT autolearn=unavailable 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 CA92BC433ED for ; Mon, 26 Apr 2021 07:33:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 962AE61263 for ; Mon, 26 Apr 2021 07:33:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232793AbhDZHeT (ORCPT ); Mon, 26 Apr 2021 03:34:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:45826 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232266AbhDZHdj (ORCPT ); Mon, 26 Apr 2021 03:33:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 22090611C9; Mon, 26 Apr 2021 07:32:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1619422376; bh=nBhsgvgZR6awp7kCZkb1y1P8PSCCT1gbuYqv3EP7ny0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rxQVHvyGEmbZer/jkiSg3dN1AtgtaOxNwxn5Rd9k63/dQhNXHOaABuM9cKi5a1hpl l+r8Tsm380vnzLTF0OPWNOs9FD7J3wcniABIg6oAeCEz3nSbwErAV/uDPH9jzBTDZY 3DTTtghlrfY2gTBFKhC1xgOq+vtHzejFx1b4jIEE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Shuah Khan , Tom Seewald , syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Subject: [PATCH 4.9 25/37] usbip: stub-dev synchronize sysfs code paths Date: Mon, 26 Apr 2021 09:29:26 +0200 Message-Id: <20210426072818.102188378@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210426072817.245304364@linuxfoundation.org> References: <20210426072817.245304364@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Shuah Khan commit 9dbf34a834563dada91366c2ac266f32ff34641a upstream. Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. Use sysfs_lock to protect sysfs paths in stub-dev. Cc: stable@vger.kernel.org # 4.9.x Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/2b182f3561b4a065bf3bf6dce3b0e9944ba17b3f.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Tom Seewald Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/stub_dev.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/drivers/usb/usbip/stub_dev.c +++ b/drivers/usb/usbip/stub_dev.c @@ -77,6 +77,7 @@ static ssize_t store_sockfd(struct devic dev_info(dev, "stub up\n"); + mutex_lock(&sdev->ud.sysfs_lock); spin_lock_irq(&sdev->ud.lock); if (sdev->ud.status != SDEV_ST_AVAILABLE) { @@ -101,13 +102,13 @@ static ssize_t store_sockfd(struct devic tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx"); if (IS_ERR(tcp_rx)) { sockfd_put(socket); - return -EINVAL; + goto unlock_mutex; } tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx"); if (IS_ERR(tcp_tx)) { kthread_stop(tcp_rx); sockfd_put(socket); - return -EINVAL; + goto unlock_mutex; } /* get task structs now */ @@ -126,6 +127,8 @@ static ssize_t store_sockfd(struct devic wake_up_process(sdev->ud.tcp_rx); wake_up_process(sdev->ud.tcp_tx); + mutex_unlock(&sdev->ud.sysfs_lock); + } else { dev_info(dev, "stub down\n"); @@ -136,6 +139,7 @@ static ssize_t store_sockfd(struct devic spin_unlock_irq(&sdev->ud.lock); usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN); + mutex_unlock(&sdev->ud.sysfs_lock); } return count; @@ -144,6 +148,8 @@ sock_err: sockfd_put(socket); err: spin_unlock_irq(&sdev->ud.lock); +unlock_mutex: + mutex_unlock(&sdev->ud.sysfs_lock); return -EINVAL; } static DEVICE_ATTR(usbip_sockfd, S_IWUSR, NULL, store_sockfd); @@ -309,6 +315,7 @@ static struct stub_device *stub_device_a sdev->ud.side = USBIP_STUB; sdev->ud.status = SDEV_ST_AVAILABLE; spin_lock_init(&sdev->ud.lock); + mutex_init(&sdev->ud.sysfs_lock); sdev->ud.tcp_socket = NULL; sdev->ud.sockfd = -1;