On Sun, Dec 09, 2018 at 10:39:52PM +0100, Luc Van Oostenryck wrote:
> There are several more or less bad/good solutions, like:
> * add raw_copy_{to,from}_user() in the list of checked function
> (not inlined in most archs).
> * add a new annotation to force sparse to check the byte count
> (I'm thinking about __range__/OP_RANGE or something similar).
> * do these checks before functions are inlined (but then some
> constant count could not yet be seen as constant).
* just spell it out in copy_to_user() itself - as in
#ifdef C_T_U_SIZE_LIMIT
if (__builtin_constant_p(count) && count > C_T_U_SIZE_LIMIT)
/* something warning-triggering */
#endif
in the beginning of copy_from_user(). Or simply
#ifdef C_T_U_SIZE_LIMIT
BUILD_BUG_ON(__builtin_constant_p(count) && count > C_T_U_SIZE_LIMIT);
#endif
in there...
