lkml.org 
[lkml]   [2023]   [Sep]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] firmware: tegra: bpmp: refactor deprecated strncpy
On Wed, Sep 13, 2023 at 07:38:44PM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
>
> We should prefer more robust and less ambiguous string interfaces.
>
> It seems like the filename stored at `namevirt` is expected to be
> NUL-terminated.

This took me a bit to establish, but yes: buf[256] is used to store
filename, so it'll always be %NUL-terminated with the 256 bytes, which
is the same size used to allocate virtname, which means it will always
be %NUL-terminated.

>
> A suitable replacement is `strscpy_pad` due to the fact that it
> guarantees NUL-termination on the destination buffer whilst maintaining
> the NUL-padding behavior that strncpy provides.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>

This one looks weird because namevirt seems unused, but I assume there's
some kind of DMA side-effect happening somewhere?

But, yes, after digging around here, I think this all looks right.

Reviewed-by: Kees Cook <keescook@chromium.org>

--
Kees Cook

\
 
 \ /
  Last update: 2023-09-15 06:02    [W:0.056 / U:0.560 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site