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 6B28B4611CE; Tue, 5 May 2026 13:40:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777988401; cv=none; b=SPW9i3uUkhP9WdOTlyfN/w63Gp6Dyp2489E1xnkNjK3OuXbfPbodBmMaGKesN5C+HOs9sGmyhRdfGxw3jQaYktfs1qNu6wwXr47ydkGX2voQBXLwTnpuYOTbt32F3Oq0tos7Q5JEKIuVyPCdxJQdyBjLGpnqwihNbRfYPDsD7IE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777988401; c=relaxed/simple; bh=8nwAo5XtwEc62prLYY61UbO6xY3/LUc3g4wHglEB8qA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tWqNmk90NKZBYU4hEJb5FP/QooyoVdlPZPOYWpNWc9zPYseOhoCYggFIZkF0o3yoDDeQKnOcjs/n2RZE5cv9xvJGgyOQ6xfmv0ughQkuXbNaDSVPcmJ/A8ojHN14faSReSX9qiZ68d2V2Y7d3KEFsNIZIs4el2r+R/JtpodxdxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D/8waH2J; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D/8waH2J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F258C2BCC7; Tue, 5 May 2026 13:39:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777988401; bh=8nwAo5XtwEc62prLYY61UbO6xY3/LUc3g4wHglEB8qA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D/8waH2J1efm3fz0FDPq1FWabuHQdeYVyf04A4+C1Lk2U0W8OECYgW/qGFk3xqne5 usouBZ3i/ChP6xllN8Uon1wMibaDaKUNUpWzH33tN6qnf7EF6k0Irp4OsCnUt2q6PK YqczwSGevx6Ep+SVKR4K4Y8cdx7WAb6wqiouwrNBZiK3m7e3lGzQ/mq9apxdOss9OR zy1jzRqNT5qPpxqygjbOTfr1YaET//D8hgdyB+QQH2s/nZ1XqiRpVJwZrpRVr79KjA 7KA5n8XW8fkGBmHV4UcQ4EhFLRAN7rmyZl+9Sn49uLfe6Q0YcRQa5s9xRUrEVIuZHY iTTexuMz0FB8w== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, linux@armlinux.org.uk, nipun.gupta@amd.com, nikhil.agarwal@amd.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, longli@microsoft.com, andersson@kernel.org, mathieu.poirier@linaro.org Cc: driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org, Danilo Krummrich , Michael Kelley , Gui-Dong Han Subject: [PATCH v2 3/5] Drivers: hv: vmbus: use generic driver_override infrastructure Date: Tue, 5 May 2026 15:37:23 +0200 Message-ID: <20260505133935.3772495-4-dakr@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260505133935.3772495-1-dakr@kernel.org> References: <20260505133935.3772495-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When a driver is probed through __driver_attach(), the bus' match() callback is called without the device lock held, thus accessing the driver_override field without a lock, which can cause a UAF. Fix this by using the driver-core driver_override infrastructure taking care of proper locking internally. Note that calling match() from __driver_attach() without the device lock held is intentional. [1] Tested-by: Michael Kelley Reviewed-by: Michael Kelley Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1] Reported-by: Gui-Dong Han Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 Fixes: d765edbb301c ("vmbus: add driver_override support") Signed-off-by: Danilo Krummrich --- drivers/hv/vmbus_drv.c | 43 ++++++++++-------------------------------- include/linux/hyperv.h | 5 ----- 2 files changed, 10 insertions(+), 38 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index d28ff45d4cfd..acfb579828c5 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -538,34 +538,6 @@ static ssize_t device_show(struct device *dev, } static DEVICE_ATTR_RO(device); -static ssize_t driver_override_store(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) -{ - struct hv_device *hv_dev = device_to_hv_device(dev); - int ret; - - ret = driver_set_override(dev, &hv_dev->driver_override, buf, count); - if (ret) - return ret; - - return count; -} - -static ssize_t driver_override_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct hv_device *hv_dev = device_to_hv_device(dev); - ssize_t len; - - device_lock(dev); - len = sysfs_emit(buf, "%s\n", hv_dev->driver_override); - device_unlock(dev); - - return len; -} -static DEVICE_ATTR_RW(driver_override); - /* Set up per device attributes in /sys/bus/vmbus/devices/ */ static struct attribute *vmbus_dev_attrs[] = { &dev_attr_id.attr, @@ -596,7 +568,6 @@ static struct attribute *vmbus_dev_attrs[] = { &dev_attr_channel_vp_mapping.attr, &dev_attr_vendor.attr, &dev_attr_device.attr, - &dev_attr_driver_override.attr, NULL, }; @@ -708,9 +679,11 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver * { const guid_t *guid = &dev->dev_type; const struct hv_vmbus_device_id *id; + int ret; - /* When driver_override is set, only bind to the matching driver */ - if (dev->driver_override && strcmp(dev->driver_override, drv->name)) + /* If a driver override is set, only bind to the matching driver */ + ret = device_match_driver_override(&dev->device, &drv->driver); + if (ret == 0) return NULL; /* Look at the dynamic ids first, before the static ones */ @@ -718,8 +691,11 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver * if (!id) id = hv_vmbus_dev_match(drv->id_table, guid); - /* driver_override will always match, send a dummy id */ - if (!id && dev->driver_override) + /* + * If there's a matching driver override, this function should succeed, + * thus return a dummy device ID if no matching ID is found. + */ + if (!id && ret > 0) id = &vmbus_device_null; return id; @@ -1021,6 +997,7 @@ static const struct dev_pm_ops vmbus_pm = { /* The one and only one */ static const struct bus_type hv_bus = { .name = "vmbus", + .driver_override = true, .match = vmbus_match, .shutdown = vmbus_shutdown, .remove = vmbus_remove, diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 964f1be8150c..c054d7eff622 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1272,11 +1272,6 @@ struct hv_device { u16 device_id; struct device device; - /* - * Driver name to force a match. Do not set directly, because core - * frees it. Use driver_set_override() to set or clear it. - */ - const char *driver_override; struct vmbus_channel *channel; struct kset *channels_kset; -- 2.54.0