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| author |   Masami Hiramatsu <mhiramat@kernel.org> | 2017-08-02 13:47:42 +0900 |
|---|---|---|
| committer |   Linus Walleij <linus.walleij@linaro.org> | 2017-08-14 15:00:43 +0200 |
| commit | 90b05b0598c698252d5f7dcdce335c5a546e9047 (patch) | |
| tree | 1ab8cbb4a65de9ec2ac18cc96e8c2976969cffec /drivers/gpio | |
| parent | Linux 4.13-rc5 (diff) | |
| download | linux-dev-90b05b0598c698252d5f7dcdce335c5a546e9047.tar.xz linux-dev-90b05b0598c698252d5f7dcdce335c5a546e9047.zip | |
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 <mhiramat@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpiolib-sysfs.c | 10 |
1 files 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 <linux/mutex.h> #include <linux/device.h> #include <linux/sysfs.h> +#include <linux/gpio.h> #include <linux/gpio/consumer.h> #include <linux/gpio/driver.h> #include <linux/interrupt.h> @@ -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); |