From: Gui-Dong Han <hanguidong02@gmail.com> stable inclusion from stable-v6.18.11 commit 1d6bd6183e723a7b256ff34bbb5b498b5f4f2ec0 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13796 CVE: CVE-2026-23221 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 148891e95014b5dc5878acefa57f1940c281c431 upstream. 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 <hanguidong02@gmail.com> Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com> Link: https://lore.kernel.org/r/20251202174438.12658-1-hanguidong02@gmail.com Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: drivers/bus/fsl-mc/fsl-mc-bus.c [Context Conflicts] Signed-off-by: Lin Ruifeng <linruifeng4@huawei.com> --- drivers/bus/fsl-mc/fsl-mc-bus.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index 0481b8a321b6..59389ad93595 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -178,12 +178,14 @@ static ssize_t driver_override_store(struct device *dev, if (cp) *cp = '\0'; + device_lock(dev); if (strlen(driver_override)) { mc_dev->driver_override = driver_override; } else { kfree(driver_override); mc_dev->driver_override = NULL; } + device_unlock(dev); kfree(old); @@ -194,8 +196,12 @@ 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 snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override); + device_lock(dev); + len = snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override); + device_unlock(dev); + return len; } static DEVICE_ATTR_RW(driver_override); -- 2.43.0