gpiolib: sanitize return values of callbacks

[PATCH 0/8] gpiolib: sanitize return values of callbacks

Posted by Bartosz Golaszewski 10 months, 1 week ago

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,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Re: [PATCH 0/8] gpiolib: sanitize return values of callbacks

Posted by Bartosz Golaszewski 9 months, 3 weeks ago

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Mon, 10 Feb 2025 11:51:54 +0100, Bartosz Golaszewski wrote:
> 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.
> 
> [...]

Applied, thanks!

[1/8] gpiolib: check the return value of gpio_chip::get_direction()
      commit: 9d846b1aebbe488f245f1aa463802ff9c34cc078
[2/8] gpiolib: sanitize the return value of gpio_chip::request()
      commit: 69920338f8130da929ade6f93e6fa3e0e68433ee
[3/8] gpiolib: sanitize the return value of gpio_chip::set_config()
      commit: dcf8f3bffa2de2c7f3b5771b63605194ccd2286f
[4/8] gpiolib: sanitize the return value of gpio_chip::get()
      commit: 86ef402d805d606a10e6da8e5a64a51f6f5fb7e2
[5/8] gpiolib: sanitize the return value of gpio_chip::get_multiple()
      commit: 74abd086d2ee5ef10f68848cfe39e271ac798685
[6/8] gpiolib: sanitize the return value of gpio_chip::direction_output()
      commit: dfeb70c86d637d49af9313245e6b1f2ead08ce9b
[7/8] gpiolib: sanitize the return value of gpio_chip::direction_input()
      commit: 4750ddce95ae8be618e31b0aa51efcf50e23a78e
[8/8] gpiolib: sanitize the return value of gpio_chip::get_direction()
      commit: e623c4303ed112a1fc20aec8427ba8407e2842e6

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Re: [PATCH 0/8] gpiolib: sanitize return values of callbacks

Posted by Linus Walleij 10 months ago

On Mon, Feb 10, 2025 at 11:52 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> 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>

This seems reasonable.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: (subset) [PATCH 0/8] gpiolib: sanitize return values of callbacks

Posted by Bartosz Golaszewski 10 months ago

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Mon, 10 Feb 2025 11:51:54 +0100, Bartosz Golaszewski wrote:
> 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.
> 
> [...]

Queued this one for fixes. The rest will be picked up next week once this
is upstream.

[1/8] gpiolib: check the return value of gpio_chip::get_direction()
      commit: 9d846b1aebbe488f245f1aa463802ff9c34cc078

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>