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Mon, 10 Feb 2025 02:52:12 -0800 (PST) Received: from [127.0.1.1] ([2a01:cb1d:dc:7e00:f3e9:47d0:94c6:777f]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38dc53ae9c0sm10557919f8f.101.2025.02.10.02.52.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Feb 2025 02:52:11 -0800 (PST) From: Bartosz Golaszewski Date: Mon, 10 Feb 2025 11:52:00 +0100 Subject: [PATCH 6/8] gpiolib: sanitize the return value of gpio_chip::direction_output() Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250210-gpio-sanitize-retvals-v1-6-12ea88506cb2@linaro.org> References: <20250210-gpio-sanitize-retvals-v1-0-12ea88506cb2@linaro.org> In-Reply-To: <20250210-gpio-sanitize-retvals-v1-0-12ea88506cb2@linaro.org> To: Linus Walleij , Bartosz Golaszewski Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=2266; i=bartosz.golaszewski@linaro.org; h=from:subject:message-id; bh=v5PaGseLV+iX53DOub4sqpS1V3bIng/nrHtGLctVVdQ=; b=owEBbQKS/ZANAwAKARGnLqAUcddyAcsmYgBnqdpT05VU7QlrO9fymh6SdG4wxJ+svHmCP6bdk bYTEogd8/6JAjMEAAEKAB0WIQQWnetsC8PEYBPSx58Rpy6gFHHXcgUCZ6naUwAKCRARpy6gFHHX ciQAD/0Y/GW+31oLwGIVNlHfLMDdu64zc6BxN76j5jU+SUqFRhYTXjvnrhNEj8N6eYT83mfS0xI EUpIOfTnApVbqXF9er69IkYITWOrB7kdv8kdlk0KYSJEVVkthBYzgwHDppdNjcMRqrGzoO7/SOP Jfcjb6h1eFVONFj7XIvPRaBwMKVoZsp8f/eUHanFvdvZBnuOQkQspsyHRcZNNTI2gt3dEHi/Sr1 Ao+CAANEx8bc/t322NflWuhwEyL7hjV6juc4soB5MuAEvjL3rmri2mXfHG7Qqm0tcFmSfKMqGMY v2p7w0MH8lwpsyKh0EyUuFXx6LiB8lmTulv+5mSSBkZBOseUz2uSoNCT578EwS/GmJLGltrGCUd 12e79Jdzg/YHg1FR5PYRrj1N5/23swbeqRiQXUXI5ZXCEwHr21y6XRwvTfuX+fUbYkamZlSgJb3 R8dnGO5rJ1q7J6QARkgrZsu50cRgelpXBdxhp9Jdpvce2S5enJQK0VGDoew3c6a6Hf4FOc9wfGC vc9jIaUdd+xumNRLcl+N5ZM0elXqBSPYYGFxxmjt+bGyp+Ae1YMKthq4qkRTPsIFJGOIHPwsL8V EUrF3Flnm3EdT4yFKIcP10LQsbU3i2pgZWxugBzL7BXHOB2HtKlKmgIfcVsQCIZiW6dw2Wr+VtV cy7E2gz6ZN2Zb7Q== X-Developer-Key: i=bartosz.golaszewski@linaro.org; a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 From: Bartosz Golaszewski The return value of the direction_output() callback may be propagated to user-space. As per the API contract it can only return 0 or a negative error number. Add a wrapper around the callback calls that filters out anything else. Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 7255f4df6a8b..1f75ae6e208c 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2683,6 +2683,23 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce) return ret; } +static int gpiochip_direction_output(struct gpio_chip *gc, unsigned int offset, + int value) +{ + int ret; + + lockdep_assert_held(&gc->gpiodev->srcu); + + if (WARN_ON(!gc->direction_output)) + return -EOPNOTSUPP; + + ret = gc->direction_output(gc, offset, value); + if (ret > 0) + ret = -EBADE; + + return ret; +} + /** * gpiod_direction_input - set the GPIO direction to input * @desc: GPIO to set to input @@ -2780,8 +2797,8 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) } if (guard.gc->direction_output) { - ret = guard.gc->direction_output(guard.gc, - gpio_chip_hwgpio(desc), val); + ret = gpiochip_direction_output(guard.gc, + gpio_chip_hwgpio(desc), val); } else { /* Check that we are in output mode if we can */ if (guard.gc->get_direction) { @@ -3433,7 +3450,7 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value) if (value) { ret = guard.gc->direction_input(guard.gc, offset); } else { - ret = guard.gc->direction_output(guard.gc, offset, 0); + ret = gpiochip_direction_output(guard.gc, offset, 0); if (!ret) set_bit(FLAG_IS_OUT, &desc->flags); } @@ -3458,7 +3475,7 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value return; if (value) { - ret = guard.gc->direction_output(guard.gc, offset, 1); + ret = gpiochip_direction_output(guard.gc, offset, 1); if (!ret) set_bit(FLAG_IS_OUT, &desc->flags); } else {