On Mon, Feb 26, 2024 at 11:53:44PM +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 expect ae->value_string to be NUL-terminated because there's a > comment that says as much; these attr strings are also used with other > string APIs, further cementing the fact. > > Now, the question of whether or not to NUL-pad the destination buffer: > lpfc_fdmi_rprt_defer() initializes vports (all zero-initialized), then > we call lpfc_fdmi_cmd() with each vport and a mask. Then, inside of > lpfc_fdmi_cmd() we check each bit in the mask to invoke the proper > callback. Importantly, the zero-initialized vport is passed in as the > "attr" parameter. Seeing this: > | struct lpfc_fdmi_attr_string *ae = attr; > ... we can tell that ae->value_string is entirely zero-initialized. Due > to this, NUL-padding is _not_ required as it would be redundant. > > Considering the above, a suitable replacement is `strscpy` [2]. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@xxxxxxxxxxxxxxx > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -- Kees Cook
