On Mon, Oct 16, 2023 at 10:38:20PM +0000, Justin Stitt 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.
>
> We should NUL-pad as there are full struct copies happening in places:
> | struct drm_mode_modeinfo umode;
> |
> | ...
> | struct drm_property_blob *blob;
> |
> | drm_mode_convert_to_umode(&umode, mode);
> | blob = drm_property_create_blob(crtc->dev,
> | sizeof(umode), &umode);
>
> A suitable replacement is `strscpy_pad` due to the fact that it
> guarantees both NUL-termination and NUL-padding on the destination
> buffer.
>
> Additionally, replace size macro `DRM_DISPLAY_MODE_LEN` with sizeof() to
> more directly tie the maximum buffer size to the destination buffer:
> | struct drm_display_mode {
> | ...
> | char name[DRM_DISPLAY_MODE_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: linux-hardening@xxxxxxxxxxxxxxx
> Cc: Xu Panda <xu.panda@xxxxxxxxxx>
> Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
Thanks for the respin; this looks good to me.
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
--
Kees Cook
