From 90b05b0598c698252d5f7dcdce335c5a546e9047 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 2 Aug 2017 13:47:42 +0900 Subject: [PATCH] gpio: reject invalid gpio before getting gpio_desc Check user-given gpio number and reject it before calling gpio_to_desc() because gpio_to_desc() is for kernel driver and it expects given gpio number is valid (means 0 to 511). If given number is invalid, gpio_to_desc() calls WARN() and dump registers and stack for debug. This means user can easily kick WARN() just by writing invalid gpio number (e.g. 512) to /sys/class/gpio/export. Fixes: 0e9a5edf5d01 ("gpio: fix deferred probe detection for legacy API") Signed-off-by: Masami Hiramatsu Reviewed-by: Andy Shevchenko Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-sysfs.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index 16fe9742597b..fc80add5fedb 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -2,6 +2,7 @@ #include #include #include +#include #include #include #include @@ -432,6 +433,11 @@ static struct attribute *gpiochip_attrs[] = { }; ATTRIBUTE_GROUPS(gpiochip); +static struct gpio_desc *gpio_to_valid_desc(int gpio) +{ + return gpio_is_valid(gpio) ? gpio_to_desc(gpio) : NULL; +} + /* * /sys/class/gpio/export ... write-only * integer N ... number of GPIO to export (full access) @@ -450,7 +456,7 @@ static ssize_t export_store(struct class *class, if (status < 0) goto done; - desc = gpio_to_desc(gpio); + desc = gpio_to_valid_desc(gpio); /* reject invalid GPIOs */ if (!desc) { pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); @@ -493,7 +499,7 @@ static ssize_t unexport_store(struct class *class, if (status < 0) goto done; - desc = gpio_to_desc(gpio); + desc = gpio_to_valid_desc(gpio); /* reject bogus commands (gpio_unexport ignores them) */ if (!desc) { pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); -- 2.20.1