[PATCH] iio: force snprintf for PAGE_SIZE bufs

[PATCH] iio: force snprintf for PAGE_SIZE bufs

[Kees Cook]

This is a tiny preventative measure to make sure we can't write beyond
PAGE_SIZE on the buffers being used in sysfs for iio. There is currently
no way for this to happen, but the change makes this code more robust
for the future.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/iio/industrialio-core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index acc911a836ca..64bb64f35af8 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -340,7 +340,7 @@ ssize_t iio_enum_read(struct iio_dev *indio_dev,
 	else if (i >= e->num_items)
 		return -EINVAL;
 
-	return sprintf(buf, "%s\n", e->items[i]);
+	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
 }
 EXPORT_SYMBOL_GPL(iio_enum_read);
 
@@ -836,7 +836,7 @@ static ssize_t iio_show_dev_name(struct device *dev,
 				 char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	return sprintf(buf, "%s\n", indio_dev->name);
+	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
 }
 
 static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
-- 
1.7.9.5


-- 
Kees Cook
Chrome OS Security

Re: [PATCH] iio: force snprintf for PAGE_SIZE bufs

[Jonathan Cameron]

On 13/03/14 16:46, Kees Cook wrote:
> This is a tiny preventative measure to make sure we can't write beyond
> PAGE_SIZE on the buffers being used in sysfs for iio. There is currently
> no way for this to happen, but the change makes this code more robust
> for the future.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
A sensible enough change I guess.

Applied to the togreg branch of iio.git

Jonathan
> ---
>   drivers/iio/industrialio-core.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index acc911a836ca..64bb64f35af8 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -340,7 +340,7 @@ ssize_t iio_enum_read(struct iio_dev *indio_dev,
>   	else if (i >= e->num_items)
>   		return -EINVAL;
>
> -	return sprintf(buf, "%s\n", e->items[i]);
> +	return snprintf(buf, PAGE_SIZE, "%s\n", e->items[i]);
>   }
>   EXPORT_SYMBOL_GPL(iio_enum_read);
>
> @@ -836,7 +836,7 @@ static ssize_t iio_show_dev_name(struct device *dev,
>   				 char *buf)
>   {
>   	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	return sprintf(buf, "%s\n", indio_dev->name);
> +	return snprintf(buf, PAGE_SIZE, "%s\n", indio_dev->name);
>   }
>
>   static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
>