We've had instances of drivers returning invalid values from gpio_chip calbacks. In several cases these return values would be propagated to user-space and confuse programs that only expect 0 or negative errnos from ioctl()s. Let's sanitize the return values of callbacks and make sure we don't allow anyone see invalid ones.
The first patch checks the return values of get_direction() in kernel where needed and is a backportable fix.
Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@linaro.org --- Bartosz Golaszewski (8): gpiolib: check the return value of gpio_chip::get_direction() gpiolib: sanitize the return value of gpio_chip::request() gpiolib: sanitize the return value of gpio_chip::set_config() gpiolib: sanitize the return value of gpio_chip::get() gpiolib: sanitize the return value of gpio_chip::get_multiple() gpiolib: sanitize the return value of gpio_chip::direction_output() gpiolib: sanitize the return value of gpio_chip::direction_input() gpiolib: sanitize the return value of gpio_chip::get_direction()
drivers/gpio/gpiolib.c | 144 +++++++++++++++++++++++++++++++++++--------- include/linux/gpio/driver.h | 6 +- 2 files changed, 120 insertions(+), 30 deletions(-) --- base-commit: a13f6e0f405ed0d3bcfd37c692c7d7fa3c052154 change-id: 20241212-gpio-sanitize-retvals-f5f4e0d6f57d
Best regards,