Re: [PATCH] checkpatch: Added warnings in favor of strscpy().

[Kees Cook <keescook@chromium.org>]

On Fri, Jun 28, 2019 at 05:25:48PM +0530, Nitin Gote wrote:
> Added warnings in checkpatch.pl script to :
> 
> 1. Deprecate strcpy() in favor of strscpy().
> 2. Deprecate strlcpy() in favor of strscpy().
> 3. Deprecate strncpy() in favor of strscpy() or strscpy_pad().
> 
> Signed-off-by: Nitin Gote <nitin.r.gote@intel.com>

Excellent, yes. Can you also add a bit to the strncpy() section in
Documentation/process/deprecated.rst so that all three cases of strncpy()
are explained:

- strncpy() into NUL-terminated target should use strscpy()
- strncpy() into NUL-terminated target needing trailing NUL: strscpy_pad()
- strncpy() into non-NUL-terminated target should have target marked
  with __nonstring.

(and probably mention the __nonstring case in checkpatch too)

-Kees

> ---
>  scripts/checkpatch.pl | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 342c7c7..bb0fa11 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -595,6 +595,9 @@ our %deprecated_apis = (
>  	"rcu_barrier_sched"			=> "rcu_barrier",
>  	"get_state_synchronize_sched"		=> "get_state_synchronize_rcu",
>  	"cond_synchronize_sched"		=> "cond_synchronize_rcu",
> +	"strcpy"				=> "strscpy",
> +	"strlcpy"				=> "strscpy",
> +	"strncpy"				=> "strscpy or strscpy_pad",
>  );
> 
>  #Create a search pattern for all these strings to speed up a loop below
> --
> 2.7.4
> 

-- 
Kees Cook