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Mon, 10 Feb 2025 02:52:07 -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.101.2025.02.10.02.52.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Feb 2025 02:52:06 -0800 (PST) From: Bartosz Golaszewski Date: Mon, 10 Feb 2025 11:51:56 +0100 Subject: [PATCH 2/8] gpiolib: sanitize the return value of gpio_chip::request() 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-v1-2-12ea88506cb2@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=1657; i=bartosz.golaszewski@linaro.org; h=from:subject:message-id; bh=xkoYB7QevhvR3b+N2NNvGIdS2HFsaFzerPPF2/0s9uc=; b=owEBbQKS/ZANAwAKARGnLqAUcddyAcsmYgBnqdpSeBElLfXXQ84Z9WEjnwnVZFBwpXL6a3buq qxEtPp/EGGJAjMEAAEKAB0WIQQWnetsC8PEYBPSx58Rpy6gFHHXcgUCZ6naUgAKCRARpy6gFHHX cttFD/9KMeATzvVcS8fkNWtmLZqCca0VOv3FIImFijcRAY1VSscZnpcKmcSFogZrPYFVPS3AwaT UmELIhw2EbSWGCN4YgmeuEcf++8V6C5MKxwU7qGmq+vPKUeySCdoc30XQuV1212EJCK2XEwDHu9 SDU5bB56HMMj0rZA43rwIUxps7o861ZL+8LPTAYakQEYQE/YhztjoYlncE7+iXlBLkfS+16eIh1 NBttreNhs0cRQS+/TfSXEBjlnMC1II6mYNCs4716Oh9jfylxLrPvdPQuwrjclzQvb9V5dHfQAtx rutAgVd/esaXieQjwPHHSGIwS8qAPQa9ZLHRE1Vsg2VfuCd9jhmjpiugDzpsZ7/LJOy1dYOuIB8 ga9X9D8Ft2x2LeBMQlTo7GYROzRXKLUjvMCrPHIsDfGXhgLOzqLCVtYHCqzMXjlWLIm7wEppYDf 1wXJg2IP4MnoCBnppWRe6wuN4UJaHMdkPJJvXLut2xzQ8Ql+uuCaIRabQdpBm0/1hYl2LTvMr5l JcOM7Z7KYcXYAI8Q/m9lDZINgILVtMZjZ00q6acCGrrGBreJ/yQofrY20Ag+MrgGQHlUhu9IX8D FN2SaOCoE4xPafKxDBKjJklp2p7UB7/YlyC87I0uLbLe81cP8LuZVRIyPxsN/t7OCY+SM8cibmv i+jiWfu5itVunew== X-Developer-Key: i=bartosz.golaszewski@linaro.org; a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 From: Bartosz Golaszewski The return value of the request() callback may be propagated to user-space. If a bad driver returns a positive number, it may confuse user programs. Tighten the API contract and check for positive numbers returned by GPIO controllers. Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib.c | 2 ++ include/linux/gpio/driver.h | 3 ++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 5d3774dc748b..42625da7e797 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2331,6 +2331,8 @@ static int gpiod_request_commit(struct gpio_desc *desc, const char *label) ret = guard.gc->request(guard.gc, offset); else ret = -EINVAL; + if (ret > 0) + ret = -EBADE; if (ret) goto out_clear_bit; } diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 2dd7cb9cc270..26fcddcb74b8 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -328,7 +328,8 @@ struct gpio_irq_chip { * @fwnode: optional fwnode providing this controller's properties * @owner: helps prevent removal of modules exporting active GPIOs * @request: optional hook for chip-specific activation, such as - * enabling module power and clock; may sleep + * enabling module power and clock; may sleep; must return 0 on success + * or negative error number on failure * @free: optional hook for chip-specific deactivation, such as * disabling module power and clock; may sleep * @get_direction: returns direction for signal "offset", 0=out, 1=in,