From 8b40c38e37492b5bdf8e95b46b5cca9517a9957a Mon Sep 17 00:00:00 2001 From: Russ Weight Date: Mon, 29 Aug 2022 10:45:57 -0700 Subject: [PATCH] firmware_loader: Fix use-after-free during unregister In the following code within firmware_upload_unregister(), the call to device_unregister() could result in the dev_release function freeing the fw_upload_priv structure before it is dereferenced for the call to module_put(). This bug was found by the kernel test robot using CONFIG_KASAN while running the firmware selftests. device_unregister(&fw_sysfs->dev); module_put(fw_upload_priv->module); The problem is fixed by copying fw_upload_priv->module to a local variable for use when calling device_unregister(). Fixes: 97730bbb242c ("firmware_loader: Add firmware-upload support") Cc: stable Reported-by: kernel test robot Reviewed-by: Matthew Gerlach Signed-off-by: Russ Weight Link: https://lore.kernel.org/r/20220829174557.437047-1-russell.h.weight@intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/sysfs_upload.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/base/firmware_loader/sysfs_upload.c b/drivers/base/firmware_loader/sysfs_upload.c index 87044d5..63e15bd 100644 --- a/drivers/base/firmware_loader/sysfs_upload.c +++ b/drivers/base/firmware_loader/sysfs_upload.c @@ -377,6 +377,7 @@ void firmware_upload_unregister(struct fw_upload *fw_upload) { struct fw_sysfs *fw_sysfs = fw_upload->priv; struct fw_upload_priv *fw_upload_priv = fw_sysfs->fw_upload_priv; + struct module *module = fw_upload_priv->module; mutex_lock(&fw_upload_priv->lock); if (fw_upload_priv->progress == FW_UPLOAD_PROG_IDLE) { @@ -392,6 +393,6 @@ void firmware_upload_unregister(struct fw_upload *fw_upload) unregister: device_unregister(&fw_sysfs->dev); - module_put(fw_upload_priv->module); + module_put(module); } EXPORT_SYMBOL_GPL(firmware_upload_unregister); -- 2.7.4