* [PATCH] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc
@ 2017-07-29 8:00 Masami Hiramatsu
2017-07-30 16:21 ` Andy Shevchenko
0 siblings, 1 reply; 3+ messages in thread
From: Masami Hiramatsu @ 2017-07-29 8:00 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-gpio, linux-kernel, Masahiro Yamada, Masami Hiramatsu,
Jassi Brar
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.
This bug has been introduced by commit 0e9a5edf5d01
("gpio: fix deferred probe detection for legacy API")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: commit 0e9a5edf5d01 ("gpio: fix deferred probe detection for legacy API")
---
drivers/gpio/gpiolib-sysfs.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 4b44dd97c07f..4efb11fd1c22 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>
@@ -443,14 +444,16 @@ static ssize_t export_store(struct class *class,
const char *buf, size_t len)
{
long gpio;
- struct gpio_desc *desc;
+ struct gpio_desc *desc = NULL;
int status;
status = kstrtol(buf, 0, &gpio);
if (status < 0)
goto done;
- desc = gpio_to_desc(gpio);
+ if (gpio_is_valid(gpio))
+ desc = gpio_to_desc(gpio);
+
/* reject invalid GPIOs */
if (!desc) {
pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
@@ -485,14 +488,16 @@ static ssize_t unexport_store(struct class *class,
const char *buf, size_t len)
{
long gpio;
- struct gpio_desc *desc;
+ struct gpio_desc *desc = NULL;
int status;
status = kstrtol(buf, 0, &gpio);
if (status < 0)
goto done;
- desc = gpio_to_desc(gpio);
+ if (gpio_is_valid(gpio))
+ desc = gpio_to_desc(gpio);
+
/* reject bogus commands (gpio_unexport ignores them) */
if (!desc) {
pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc
2017-07-29 8:00 [PATCH] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc Masami Hiramatsu
@ 2017-07-30 16:21 ` Andy Shevchenko
2017-07-31 0:54 ` Masami Hiramatsu
0 siblings, 1 reply; 3+ messages in thread
From: Andy Shevchenko @ 2017-07-30 16:21 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Linus Walleij, linux-gpio@vger.kernel.org,
linux-kernel@vger.kernel.org, Masahiro Yamada, Masami Hiramatsu,
Jassi Brar
On Sat, Jul 29, 2017 at 11:00 AM, Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 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.
> This bug has been introduced by commit 0e9a5edf5d01
> ("gpio: fix deferred probe detection for legacy API")
Why so narrow paraghraps? We don't do two column articles :-)
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Fixes: commit 0e9a5edf5d01 ("gpio: fix deferred probe detection for legacy API")
If you use git tools directly, like
% git commit -s --amend
you will immediately notice that your SoB line is supposed to be the last one.
Besides above, word "commit" is not needed in Fixes: tag IIRC.
> --- 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>
> @@ -443,14 +444,16 @@ static ssize_t export_store(struct class *class,
> - struct gpio_desc *desc;
> + struct gpio_desc *desc = NULL;
> - desc = gpio_to_desc(gpio);
> + if (gpio_is_valid(gpio))
> + desc = gpio_to_desc(gpio);
Twice repeatition is a candidate for a helper, like:
static inline struct gpio_desc *gpio_to_valid_desc(int gpio)
{
return gpio_is_valid(gpio) ? gpio_to_desc(gpio) : NULL;
}
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc
2017-07-30 16:21 ` Andy Shevchenko
@ 2017-07-31 0:54 ` Masami Hiramatsu
0 siblings, 0 replies; 3+ messages in thread
From: Masami Hiramatsu @ 2017-07-31 0:54 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linus Walleij, linux-gpio@vger.kernel.org,
linux-kernel@vger.kernel.org, Masahiro Yamada, Masami Hiramatsu,
Jassi Brar
On Sun, 30 Jul 2017 19:21:36 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> On Sat, Jul 29, 2017 at 11:00 AM, Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > 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.
>
> > This bug has been introduced by commit 0e9a5edf5d01
> > ("gpio: fix deferred probe detection for legacy API")
>
> Why so narrow paraghraps? We don't do two column articles :-)
OK, I'll remove this, since Fixes explain that.
>
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Fixes: commit 0e9a5edf5d01 ("gpio: fix deferred probe detection for legacy API")
>
> If you use git tools directly, like
>
> % git commit -s --amend
>
> you will immediately notice that your SoB line is supposed to be the last one.
I'll move SoB line to the bottom.
>
> Besides above, word "commit" is not needed in Fixes: tag IIRC.
Ah, OK, I'll remove "commit" from Fixes.
>
>
> > --- 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>
>
> > @@ -443,14 +444,16 @@ static ssize_t export_store(struct class *class,
>
> > - struct gpio_desc *desc;
> > + struct gpio_desc *desc = NULL;
>
> > - desc = gpio_to_desc(gpio);
> > + if (gpio_is_valid(gpio))
> > + desc = gpio_to_desc(gpio);
>
> Twice repeatition is a candidate for a helper, like:
>
> static inline struct gpio_desc *gpio_to_valid_desc(int gpio)
> {
> return gpio_is_valid(gpio) ? gpio_to_desc(gpio) : NULL;
> }
OK, I'll add the helper.
Thanks,
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-07-29 8:00 [PATCH] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc Masami Hiramatsu
2017-07-30 16:21 ` Andy Shevchenko
2017-07-31 0:54 ` Masami Hiramatsu
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