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 238BA3B7A8; Sat, 4 Apr 2026 15:02:15 +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=1775314936; cv=none; b=hXy9wh6iRLHCgPLpwTcrMVazPACLWQ7Nh9iBsM8SymD9oawhjS87W3ieISdwGRqkxuPaO3agP6XPnj0eW8+V/n0gD+GqZAYcfzwKcbbTlbBR2BmRauKV9eOfq3mOPwl+K2JzC3zN0KUzvHiElzZrf0ypqZEr9Pfxj98ZpcnmBqk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775314936; c=relaxed/simple; bh=yS1a8GmMxhd+gaXjsrUMOyEcZUcN2vLf71oRyrhAVkk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U7whb4p0v2gfusZtNmzpc2g52jEEGYJwWhUfkdYnueaq0aVlNCTCg7MAvWKVqc6K91kFLa9il1ZJMXRQaqmhCo8VXCUU2Zh9MSNm5PXOjGXQ57XJ+RRvOcZVNMk8DUx3DQ7OfD6Ei/IAH07RXc/ud58vcvc9rrLW1G5sjTxG6o0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fcd1WH1u; 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="fcd1WH1u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9BB2C19421; Sat, 4 Apr 2026 15:02:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775314935; bh=yS1a8GmMxhd+gaXjsrUMOyEcZUcN2vLf71oRyrhAVkk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fcd1WH1uMPDFcW95A5bP6twrmSlGywxDbhV9K4GUdxmnw9OhLho72J9OlIZREDDfv Evf5eg+FhGKnEBZMEi0xrGzL0W0wBBPFC5ZbOalQpNWyhGwDm3HuLGvy/jgjYAq60X Jsa257f9xIzRC/LnmHpxdh9mv/JRHNm7utYMn96WoZP6ZRATrlwe1+3BmjlR9bxRPR tiA87cPHB5ojtZQJ2zSKPbtecnXGON24oyWbrZcP9XuN+XivvmLrVCQGu5orrMZe/a +xDtWMIwREbTcGNYdTKbgyxE7aDCuXqmHaashK055GEOETa+XQlaspyrGVn7GrwOhI UHZOaAkc+kiUA== From: Danilo Krummrich To: Russell King , Greg Kroah-Hartman , "Rafael J. Wysocki" , Ioana Ciornei , Nipun Gupta , Nikhil Agarwal , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Bjorn Helgaas , Armin Wolf , Bjorn Andersson , Mathieu Poirier , Vineeth Vijayan , Peter Oberparleiter , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Harald Freudenberger , Holger Dengler , Mark Brown , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Alex Williamson , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , "Christophe Leroy (CS GROUP)" Cc: linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-spi@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-arm-kernel@lists.infradead.org, Danilo Krummrich , Michael Kelley , Gui-Dong Han Subject: [PATCH v2] Drivers: hv: vmbus: use generic driver_override infrastructure Date: Sat, 4 Apr 2026 17:01:49 +0200 Message-ID: <20260404150155.3473682-1-dakr@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-s390@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 --- Changes in v2: - Change patch subject and comments according to Michael's suggestion. --- 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 bc4fc1951ae1..ba7326ec6add 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -541,34 +541,6 @@ 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, @@ -599,7 +571,6 @@ 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, }; @@ -711,9 +682,11 @@ 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 */ @@ -721,8 +694,11 @@ 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; @@ -1024,6 +1000,7 @@ 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 dfc516c1c719..bf689d07d750 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; -- 2.53.0