From: Danilo Krummrich <dakr@kernel.org> mainline inclusion from mainline-v7.0-rc6 commit cc34d77dd48708d810c12bfd6f5bf03304f6c824 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14224 CVE: CVE-2026-31487 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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] Also note that we do not enable the driver_override feature of struct bus_type, as SPI - in contrast to most other buses - passes "" to sysfs_emit() when the driver_override pointer is NULL. Thus, printing "\n" instead of "(null)\n". Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1] Reported-by: Gui-Dong Han <hanguidong02@gmail.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 Fixes: 5039563e7c25 ("spi: Add driver_override SPI device attribute") Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://patch.msgid.link/20260324005919.2408620-12-dakr@kernel.org Signed-off-by: Mark Brown <broonie@kernel.org> Conflicts: include/linux/spi/spi.h drivers/spi/spi.c [commit 702ca0269ed56 merged] Signed-off-by: Zhang Yuwei <zhangyuwei20@huawei.com> --- drivers/spi/spi.c | 19 +++++++------------ include/linux/spi/spi.h | 5 ----- 2 files changed, 7 insertions(+), 17 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 2ca4ea45e3b2..b9774bcaa678 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -49,7 +49,6 @@ static void spidev_release(struct device *dev) struct spi_device *spi = to_spi_device(dev); spi_controller_put(spi->controller); - kfree(spi->driver_override); free_percpu(spi->pcpu_statistics); kfree(spi); } @@ -72,10 +71,9 @@ static ssize_t driver_override_store(struct device *dev, struct device_attribute *a, const char *buf, size_t count) { - struct spi_device *spi = to_spi_device(dev); int ret; - ret = driver_set_override(dev, &spi->driver_override, buf, count); + ret = __device_set_driver_override(dev, buf, count); if (ret) return ret; @@ -85,13 +83,8 @@ static ssize_t driver_override_store(struct device *dev, static ssize_t driver_override_show(struct device *dev, struct device_attribute *a, char *buf) { - const struct spi_device *spi = to_spi_device(dev); - ssize_t len; - - device_lock(dev); - len = sysfs_emit(buf, "%s\n", spi->driver_override ? : ""); - device_unlock(dev); - return len; + guard(spinlock)(&dev->driver_override.lock); + return sysfs_emit(buf, "%s\n", dev->driver_override.name ?: ""); } static DEVICE_ATTR_RW(driver_override); @@ -377,10 +370,12 @@ static int spi_match_device(struct device *dev, struct device_driver *drv) { const struct spi_device *spi = to_spi_device(dev); const struct spi_driver *sdrv = to_spi_driver(drv); + int ret; /* Check override first, and if set, only use the named driver */ - if (spi->driver_override) - return strcmp(spi->driver_override, drv->name) == 0; + ret = device_match_driver_override(dev, drv); + if (ret >= 0) + return ret; /* Attempt an OF style match */ if (of_driver_match_device(dev, drv)) diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index e5baf43bcfbb..3f6ca8052f63 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -153,10 +153,6 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg, * @modalias: Name of the driver to use with this device, or an alias * for that name. This appears in the sysfs "modalias" attribute * for driver coldplugging, and in uevents used for hotplugging - * @driver_override: If the name of a driver is written to this attribute, then - * the device will bind to the named driver and only the named driver. - * Do not set directly, because core frees it; use driver_set_override() to - * set or clear it. * @cs_gpiod: GPIO descriptor of the chipselect line (optional, NULL when * not using a GPIO line) * @word_delay: delay to be inserted between consecutive @@ -212,7 +208,6 @@ struct spi_device { void *controller_state; void *controller_data; char modalias[SPI_NAME_SIZE]; - const char *driver_override; struct gpio_desc *cs_gpiod; /* Chip select GPIO descriptor */ struct spi_delay word_delay; /* Inter-word delay */ /* CS delays */ -- 2.22.0