2014-10-18 22:12:45

by Rickard Strandqvist

Subject: [PATCH 3/5] video: fbdev: uvesafb.c: Cleaning up missing null-terminate by switching from strncpy to strzcpy

Ensures that the string is null-terminate in connection with the
use of strncpy, by switching from strncpy to strzcpy.

Signed-off-by: Rickard Strandqvist <[email protected]>
---
drivers/video/fbdev/uvesafb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/uvesafb.c b/drivers/video/fbdev/uvesafb.c
index 509d452..3383b34 100644
--- a/drivers/video/fbdev/uvesafb.c
+++ b/drivers/video/fbdev/uvesafb.c
@@ -1892,7 +1892,7 @@ static ssize_t show_v86d(struct device_driver *dev, char *buf)
static ssize_t store_v86d(struct device_driver *dev, const char *buf,
size_t count)
{
- strncpy(v86d_path, buf, PATH_MAX);
+ strzcpy(v86d_path, buf, sizeof(v86d_path));
return count;
}

--
1.7.10.4

2014-10-20 07:10:43

by Geert Uytterhoeven

Subject: Re: [PATCH 3/5] video: fbdev: uvesafb.c: Cleaning up missing null-terminate by switching from strncpy to strzcpy

On Sun, Oct 19, 2014 at 12:14 AM, Rickard Strandqvist
<[email protected]> wrote:
> Ensures that the string is null-terminate in connection with the
> use of strncpy, by switching from strncpy to strzcpy.
>
> Signed-off-by: Rickard Strandqvist <[email protected]>
> ---
> drivers/video/fbdev/uvesafb.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/fbdev/uvesafb.c b/drivers/video/fbdev/uvesafb.c
> index 509d452..3383b34 100644
> --- a/drivers/video/fbdev/uvesafb.c
> +++ b/drivers/video/fbdev/uvesafb.c
> @@ -1892,7 +1892,7 @@ static ssize_t show_v86d(struct device_driver *dev, char *buf)
> static ssize_t store_v86d(struct device_driver *dev, const char *buf,
> size_t count)
> {
> - strncpy(v86d_path, buf, PATH_MAX);
> + strzcpy(v86d_path, buf, sizeof(v86d_path));

I think strlcpy() should be good enough here?
Or am I missing a reason why the rest of the buffer should be zero-filled?

Nevertheless, I think this (or an alternative) change should be applied to
stable, as call_usermodehelper() might crash by writing to sysfs.

> return count;
> }

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds