From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D979D36A352; Wed, 20 May 2026 17:17:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779297448; cv=none; b=OPFWngyqxYB4FkikMr9y3yNYf4ojEV0+WASKyuX3B+usxVX2FAQNxrNoCuO8DqbcMT5pmwznYIPciiviFBR2FZIntL81SwJJivo63b4aIBjhEx+3mxurVxskbShFIxr0VkDX8t2jOxs2hv3DtyDvOa586OXX9aBJtdO/9lA7t+I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779297448; c=relaxed/simple; bh=H5kCx4am+uzCGk++Yv5pO0AvGwaKCCRs5aVjGP0exvs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sGAoJeDkZJj0qjPfefoxc0XeS7NJXiAgeGcrNpK5gHrPrBLqi5c94LQL4eUeMIu5u53FHnef2KRLD9J0M3NS75dEIlhc2JB1Frrioq+BraIVjzR9OCY8og9eRNQzA5O2z7YAzpjzQqvGkfjMzeZEmjg/qJBzNup9bF+pbvT7vZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cbJ7JpsX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cbJ7JpsX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B8301F000E9; Wed, 20 May 2026 17:17:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779297446; bh=cpNhUOmzL4dhy/cRd8Cp26iva5qB+GlGq5zD8+jiEVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cbJ7JpsXdYaHq62/JZGLd/5/3EGU314+WQ5Ycm0qClpZvEVBSfU7Fpq4QE28CGBD6 G/0xm1XGd/yfq9ze4NwgHMnisDNEhQEQuPFvJSfeHbpZC5ZhJVnzke5tzZsz/lfS9K jdqLVDpyHQ+zoZfdD7aGEEAFOZxRYbUpuwlZ2VYU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ioana Ciornei , "Christophe Leroy (CS GROUP)" , Gui-Dong Han , Danilo Krummrich , Sasha Levin Subject: [PATCH 6.18 034/957] bus: fsl-mc: use generic driver_override infrastructure Date: Wed, 20 May 2026 18:08:37 +0200 Message-ID: <20260520162135.299414489@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162134.554764788@linuxfoundation.org> References: <20260520162134.554764788@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Danilo Krummrich [ Upstream commit 6c8dfb0362732bf1e4829867a2a5239fedc592d0 ] 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: Ioana Ciornei Acked-by: Ioana Ciornei Acked-by: Christophe Leroy (CS GROUP) 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: 1f86a00c1159 ("bus/fsl-mc: add support for 'driver_override' in the mc-bus") Link: https://patch.msgid.link/20260324005919.2408620-3-dakr@kernel.org Signed-off-by: Danilo Krummrich Signed-off-by: Sasha Levin --- drivers/bus/fsl-mc/fsl-mc-bus.c | 43 +++++-------------------------- drivers/vfio/fsl-mc/vfio_fsl_mc.c | 4 +-- include/linux/fsl/mc.h | 4 --- 3 files changed, 8 insertions(+), 43 deletions(-) diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index eb7b6c0ba9e7c..996379ace3764 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -86,12 +86,16 @@ static int fsl_mc_bus_match(struct device *dev, const struct device_driver *drv) struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev); const struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv); bool found = false; + int ret; /* When driver_override is set, only bind to the matching driver */ - if (mc_dev->driver_override) { - found = !strcmp(mc_dev->driver_override, mc_drv->driver.name); + ret = device_match_driver_override(dev, drv); + if (ret > 0) { + found = true; goto out; } + if (ret == 0) + goto out; if (!mc_drv->match_id_table) goto out; @@ -181,39 +185,8 @@ 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 fsl_mc_device *mc_dev = to_fsl_mc_device(dev); - int ret; - - if (WARN_ON(dev->bus != &fsl_mc_bus_type)) - return -EINVAL; - - ret = driver_set_override(dev, &mc_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 fsl_mc_device *mc_dev = to_fsl_mc_device(dev); - ssize_t len; - - device_lock(dev); - len = sysfs_emit(buf, "%s\n", mc_dev->driver_override); - device_unlock(dev); - return len; -} -static DEVICE_ATTR_RW(driver_override); - static struct attribute *fsl_mc_dev_attrs[] = { &dev_attr_modalias.attr, - &dev_attr_driver_override.attr, NULL, }; @@ -316,6 +289,7 @@ ATTRIBUTE_GROUPS(fsl_mc_bus); const struct bus_type fsl_mc_bus_type = { .name = "fsl-mc", + .driver_override = true, .match = fsl_mc_bus_match, .uevent = fsl_mc_bus_uevent, .dma_configure = fsl_mc_dma_configure, @@ -925,9 +899,6 @@ static struct notifier_block fsl_mc_nb; */ void fsl_mc_device_remove(struct fsl_mc_device *mc_dev) { - kfree(mc_dev->driver_override); - mc_dev->driver_override = NULL; - /* * The device-specific remove callback will get invoked by device_del() */ diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c index 76ccbab0e3d64..84cd0eb65c471 100644 --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c @@ -430,9 +430,7 @@ static int vfio_fsl_mc_bus_notifier(struct notifier_block *nb, if (action == BUS_NOTIFY_ADD_DEVICE && vdev->mc_dev == mc_cont) { - mc_dev->driver_override = kasprintf(GFP_KERNEL, "%s", - vfio_fsl_mc_ops.name); - if (!mc_dev->driver_override) + if (device_set_driver_override(dev, vfio_fsl_mc_ops.name)) dev_warn(dev, "VFIO_FSL_MC: Setting driver override for device in dprc %s failed\n", dev_name(&mc_cont->dev)); else diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h index 897d6211c1635..1da63f2d70401 100644 --- a/include/linux/fsl/mc.h +++ b/include/linux/fsl/mc.h @@ -178,9 +178,6 @@ struct fsl_mc_obj_desc { * @regions: pointer to array of MMIO region entries * @irqs: pointer to array of pointers to interrupts allocated to this device * @resource: generic resource associated with this MC object device, if any. - * @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. * * Generic device object for MC object devices that are "attached" to a * MC bus. @@ -214,7 +211,6 @@ struct fsl_mc_device { struct fsl_mc_device_irq **irqs; struct fsl_mc_resource *resource; struct device_link *consumer_link; - const char *driver_override; }; #define to_fsl_mc_device(_dev) \ -- 2.53.0