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 D45053F1668; Tue, 5 May 2026 13:39:56 +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=1777988396; cv=none; b=gLBi3xxSWwb3EDksgXPpHbfdvr1o+GMfHJti28TGif/5rY+4McauxG7Kg3VcQcinkUaRF0VEFfCf2q4r7yTTDYzelJJYLPushuhUU9gyPt4rAWz+Z02aRJacTQ7H50Baryg20yDbP52cIYmF8eKrp3bsjcJtVJ1SKKVelmpDILQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777988396; c=relaxed/simple; bh=kcjC/HW2HNG3Ncw9EG7raccDRsFJ6UdMh53CNSoiCUo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d6gE7z0a5WRBSvcAoPpeU8JbdX3mgNNIslhxDGGBnTgA9vpABMOgTO1IO8BOYI0ikBKuitFQXEZKMiANfbNS57NwnsDJEU0X6CwLiEPMuVEhDUfsdytrsSEG1iZvJoNNIMyqUAhzX5FoEWZvwvAR3a4x8DVcU8btD5pFuIOAyEg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UJkdMEcM; 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="UJkdMEcM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23D77C2BCC7; Tue, 5 May 2026 13:39:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777988396; bh=kcjC/HW2HNG3Ncw9EG7raccDRsFJ6UdMh53CNSoiCUo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UJkdMEcMbB0ZInoqZtF8Lz16OhqvF0tVkjjLp70E0yP+jbd1xYCvyLq0vNC85+sGx EEKdlKd1uuQn6NF4G4GmK9A0EjwVnPGT+EKB7OZ2hVzxPFA+dh7gcwoTDnVPiZQpQ1 BhlviWzgsRGVtUfZvusHJB/I34Q9I1Vpysg+Dai8M/DVFRQy+jRwUEeutXfceg7bZS MCZvPxESr8RIBlxfMC0HnuFvaauOHgLpHA8+TDjVBbSdOnY6ivDWMSx1Z8VOAHzX8K sa8Je8oz2wn0rR4L3D7CgGAm4Bj449I44squSv43DQcrcuV8P7b5/SknzxD0hca3Fr Fp8pqGOEea5KA== 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 , Gui-Dong Han Subject: [PATCH v2 2/5] cdx: use generic driver_override infrastructure Date: Tue, 5 May 2026 15:37:22 +0200 Message-ID: <20260505133935.3772495-3-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] 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: 2959ab247061 ("cdx: add the cdx bus driver") Signed-off-by: Danilo Krummrich --- drivers/cdx/cdx.c | 40 +++++-------------------------------- include/linux/cdx/cdx_bus.h | 4 ---- 2 files changed, 5 insertions(+), 39 deletions(-) diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c index 9196dc50a48d..d3d230247262 100644 --- a/drivers/cdx/cdx.c +++ b/drivers/cdx/cdx.c @@ -156,8 +156,6 @@ static int cdx_unregister_device(struct device *dev, } else { cdx_destroy_res_attr(cdx_dev, MAX_CDX_DEV_RESOURCES); debugfs_remove_recursive(cdx_dev->debugfs_dir); - kfree(cdx_dev->driver_override); - cdx_dev->driver_override = NULL; } /* @@ -268,6 +266,7 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv) const struct cdx_driver *cdx_drv = to_cdx_driver(drv); const struct cdx_device_id *found_id = NULL; const struct cdx_device_id *ids; + int ret; if (cdx_dev->is_bus) return false; @@ -275,7 +274,8 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv) ids = cdx_drv->match_id_table; /* When driver_override is set, only bind to the matching driver */ - if (cdx_dev->driver_override && strcmp(cdx_dev->driver_override, drv->name)) + ret = device_match_driver_override(dev, drv); + if (ret == 0) return false; found_id = cdx_match_id(ids, cdx_dev); @@ -289,7 +289,7 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv) */ if (!found_id->override_only) return true; - if (cdx_dev->driver_override) + if (ret > 0) return true; ids = found_id + 1; @@ -453,36 +453,6 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RO(modalias); -static ssize_t driver_override_store(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) -{ - struct cdx_device *cdx_dev = to_cdx_device(dev); - int ret; - - if (WARN_ON(dev->bus != &cdx_bus_type)) - return -EINVAL; - - ret = driver_set_override(dev, &cdx_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 cdx_device *cdx_dev = to_cdx_device(dev); - ssize_t len; - - device_lock(dev); - len = sysfs_emit(buf, "%s\n", cdx_dev->driver_override); - device_unlock(dev); - return len; -} -static DEVICE_ATTR_RW(driver_override); - static ssize_t enable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -552,7 +522,6 @@ static struct attribute *cdx_dev_attrs[] = { &dev_attr_class.attr, &dev_attr_revision.attr, &dev_attr_modalias.attr, - &dev_attr_driver_override.attr, NULL, }; @@ -646,6 +615,7 @@ ATTRIBUTE_GROUPS(cdx_bus); const struct bus_type cdx_bus_type = { .name = "cdx", + .driver_override = true, .match = cdx_bus_match, .probe = cdx_probe, .remove = cdx_remove, diff --git a/include/linux/cdx/cdx_bus.h b/include/linux/cdx/cdx_bus.h index b1ba97f6c9ad..f54770f110bc 100644 --- a/include/linux/cdx/cdx_bus.h +++ b/include/linux/cdx/cdx_bus.h @@ -137,9 +137,6 @@ struct cdx_controller { * @enabled: is this bus enabled * @msi_dev_id: MSI Device ID associated with CDX device * @num_msi: Number of MSI's supported by the device - * @driver_override: driver name to force a match; do not set directly, - * because core frees it; use driver_set_override() to - * set or clear it. * @irqchip_lock: lock to synchronize irq/msi configuration * @msi_write_pending: MSI write pending for this device */ @@ -165,7 +162,6 @@ struct cdx_device { bool enabled; u32 msi_dev_id; u32 num_msi; - const char *driver_override; struct mutex irqchip_lock; bool msi_write_pending; }; -- 2.54.0