#include <u.h>#include <libc.h>#include <auth.h>#include <authsrv.h>#include "authlocal.h" /* * compute the proper response.  We encrypt the ascii of * challenge number, with trailing binary zero fill. * This process was derived empirically. * this was copied from inet's guard. */static voidnetresp(char *key, long chal, char *answer){	uchar buf[8]; 	memset(buf, 0, sizeof buf);	snprint((char *)buf, sizeof buf, "%lud", chal);	if(encrypt(key, buf, 8) < 0)		abort();	sprint(answer, "%.8ux", buf[0]<<24 | buf[1]<<16 | buf[2]<<8 | buf[3]);} AuthInfo*auth_userpasswd(char *user, char *passwd){	char key[DESKEYLEN], resp[16];	AuthInfo *ai;	Chalstate *ch; 	/*	 * Probably we should have a factotum protocol	 * to check a raw password.  For now, we use	 * p9cr, which is simplest to speak.	 */	if((ch = auth_challenge("user=%q proto=p9cr role=server", user)) == nil)		return nil; 	passtokey(key, passwd);	netresp(key, atol(ch->chal), resp);	memset(key, 0, sizeof key); 	ch->resp = resp;	ch->nresp = strlen(resp);	ai = auth_response(ch);	auth_freechal(ch);	return ai;}