From: Gui-Dong Han Date: Tue, 2 Dec 2025 17:44:38 +0000 (+0800) Subject: bus: fsl-mc: fix use-after-free in driver_override_show() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=148891e95014b5dc5878acefa57f1940c281c431;p=thirdparty%2Fkernel%2Flinux.git bus: fsl-mc: fix use-after-free in driver_override_show() The driver_override_show() function reads the driver_override string without holding the device_lock. However, driver_override_store() uses driver_set_override(), which modifies and frees the string while holding the device_lock. This can result in a concurrent use-after-free if the string is freed by the store function while being read by the show function. Fix this by holding the device_lock around the read operation. Fixes: 1f86a00c1159 ("bus/fsl-mc: add support for 'driver_override' in the mc-bus") Cc: stable@vger.kernel.org Signed-off-by: Gui-Dong Han Reviewed-by: Ioana Ciornei Link: https://lore.kernel.org/r/20251202174438.12658-1-hanguidong02@gmail.com Signed-off-by: Christophe Leroy (CS GROUP) --- diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index c08c04047ae2c..08b99b0b342f3 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -231,8 +231,12 @@ 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; - return sysfs_emit(buf, "%s\n", mc_dev->driver_override); + device_lock(dev); + len = sysfs_emit(buf, "%s\n", mc_dev->driver_override); + device_unlock(dev); + return len; } static DEVICE_ATTR_RW(driver_override);