Justin Stitt <[email protected]> wrote:
> strncpy() is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> `extra` is intended to be NUL-terminated which is evident by the manual
> assignment of a NUL-byte as well as its immediate usage with strlen().
>
> Moreover, many of these getters and setters are NUL-padding buffers with
> memset():
> 2439 | memset(&tx_power, 0, sizeof(tx_power));
> 9998 | memset(sys_config, 0, sizeof(struct ipw_sys_config));
> 10084 | memset(tfd, 0, sizeof(*tfd));
> 10261 | memset(&dummystats, 0, sizeof(dummystats));
> ... let's maintain this behavior and NUL-pad our destination buffer.
>
> Considering the above, a suitable replacement is `strscpy_pad` due to
> the fact that it guarantees both NUL-termination and NUL-padding on the
> destination buffer.
>
> To be clear, there is no bug in the current implementation as
> MAX_WX_STRING is much larger than the size of the string literals being
> copied from. Also, strncpy() does NUL-pad the destination buffer and
> using strscpy_pad() simply matches that behavior. All in all, there
> should be no functional change but we are one step closer to eliminating
> usage of strncpy().
>
> Do note that we cannot use the more idiomatic strscpy invocation of
> (dest, src, sizeof(dest)) as the destination buffer cannot have its size
> determined at compile time. So, let's stick with (dest, src, LEN).
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> Reviewed-by: Kees Cook <[email protected]>
Patch applied to wireless-next.git, thanks.
8890b9bca38f wifi: ipw2x00: replace deprecated strncpy with strscpy_pad
--
https://patchwork.kernel.org/project/linux-wireless/patch/20231017-strncpy-drivers-net-wireless-intel-ipw2x00-ipw2200-c-v2-1-465e10dc817c@google.com/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches