Re: [PATCH] fs - fix name overwrite in __register_chrdev_region

Andrew Morton
2008-12-16T05:58:19Z

On Sun, 14 Dec 2008 00:49:11 +0300 Cyrill Gorcunov <gorcunov@gmail.com> wrote:

> It's possible to register chdev with a name size
> exactly the same as was allocated in structure.
> It seems it was not intedned behaviour.
>
> At least chrdev_show does not like it.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
> ---
>
> fs/char_dev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6.git/fs/char_dev.c
> ===================================================================
> --- linux-2.6.git.orig/fs/char_dev.c
> +++ linux-2.6.git/fs/char_dev.c
> @@ -120,7 +120,7 @@ __register_chrdev_region(unsigned int ma
> cd->major = major;
> cd->baseminor = baseminor;
> cd->minorct = minorct;
> - strncpy(cd->name,name, 64);
> + strncpy(cd->name, name, sizeof(cd->name) - 1);
>
> i = major_to_index(major);
>

OK.

strlcpy() prodces a more pleasing result:

--- a/fs/char_dev.c~fs-fix-name-overwrite-in-__register_chrdev_region
+++ a/fs/char_dev.c
@@ -120,7 +120,7 @@ __register_chrdev_region(unsigned int ma
cd->major = major;
cd->baseminor = baseminor;
cd->minorct = minorct;
- strncpy(cd->name,name, 64);
+ strlcpy(cd->name, name, sizeof(cd->name));

i = major_to_index(major);

_