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[209.132.180.67]) by mx.google.com with ESMTP id h48si3202592ede.31.2019.10.17.22.00.30; Thu, 17 Oct 2019 22:00:53 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=rFr5wOCY; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389055AbfJPWRs (ORCPT + 99 others); Wed, 16 Oct 2019 18:17:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:44774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2395050AbfJPVyo (ORCPT ); Wed, 16 Oct 2019 17:54:44 -0400 Received: from localhost (unknown [192.55.54.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 763ED21A49; Wed, 16 Oct 2019 21:54:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571262883; bh=fSF9rDv2ZTD2EnBy8DBvgiFivImjgF+owUIyXXBCkMw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rFr5wOCYPK+IsTr72xW2rdI3qjMlC8utRBSDhRXsFdGg0HFDFJvff1hThvte611uQ 6wVCDxbGsrK8yxER+94A7DArfrL5fqA8450niVb9vPUnqnoa3u8jcjExnfrxURGVc8 /io9KqvCONsdcl6QR7M6hvtXKUvDMgVjH6/FwvFA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Hovold Subject: [PATCH 4.9 41/92] USB: usb-skeleton: fix NULL-deref on disconnect Date: Wed, 16 Oct 2019 14:50:14 -0700 Message-Id: <20191016214832.452877889@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214759.600329427@linuxfoundation.org> References: <20191016214759.600329427@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold commit bed5ef230943863b9abf5eae226a20fad9a8ff71 upstream. The driver was using its struct usb_interface pointer as an inverted disconnected flag and was setting it to NULL before making sure all completion handlers had run. This could lead to NULL-pointer dereferences in the dev_err() statements in the completion handlers which relies on said pointer. Fix this by using a dedicated disconnected flag. Note that this is also addresses a NULL-pointer dereference at release() and a struct usb_interface reference leak introduced by a recent runtime PM fix, which depends on and should have been submitted together with this patch. Fixes: 4212cd74ca6f ("USB: usb-skeleton.c: remove err() usage") Fixes: 5c290a5e42c3 ("USB: usb-skeleton: fix runtime PM after driver unbind") Cc: stable Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20191009170944.30057-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usb-skeleton.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/usb/usb-skeleton.c +++ b/drivers/usb/usb-skeleton.c @@ -63,6 +63,7 @@ struct usb_skel { spinlock_t err_lock; /* lock for errors */ struct kref kref; struct mutex io_mutex; /* synchronize I/O with disconnect */ + unsigned long disconnected:1; wait_queue_head_t bulk_in_wait; /* to wait for an ongoing read */ }; #define to_skel_dev(d) container_of(d, struct usb_skel, kref) @@ -239,7 +240,7 @@ static ssize_t skel_read(struct file *fi if (rv < 0) return rv; - if (!dev->interface) { /* disconnect() was called */ + if (dev->disconnected) { /* disconnect() was called */ rv = -ENODEV; goto exit; } @@ -420,7 +421,7 @@ static ssize_t skel_write(struct file *f /* this lock makes sure we don't submit URBs to gone devices */ mutex_lock(&dev->io_mutex); - if (!dev->interface) { /* disconnect() was called */ + if (dev->disconnected) { /* disconnect() was called */ mutex_unlock(&dev->io_mutex); retval = -ENODEV; goto error; @@ -580,7 +581,7 @@ static void skel_disconnect(struct usb_i /* prevent more I/O from starting */ mutex_lock(&dev->io_mutex); - dev->interface = NULL; + dev->disconnected = 1; mutex_unlock(&dev->io_mutex); usb_kill_anchored_urbs(&dev->submitted);