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/* $Id$
* MegaZeux
*
* Copyright (C) 1996 Greg Janson
* Copyright (C) 1998 Matthew D. Williams - dbwilli@scsn.net
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* Code to save and retrieve password info from an open file and to
derive an xor code from the current password. */
/* Also contains password checking and changing code/dialogs. */
#include "helpsys.h"
#include "graphics.h"
#include "error.h"
#include "data.h"
#include "password.h"
#include <stdio.h>
#include "string.h"
#include "window.h"
#include "intake.h"
/* Note that all comparisons between stored and entered passwords should
not be case sensitive. The stored version can have any mixture of
upper and lower- it won't affect the comparison any. It WILL affect the
XOR code, but since the upper/lower is saved also it doesn't matter. */
char far magic_code[16]="æRëòmMJ·‡²’ˆÞ‘$";
char far work_area[16];
//Write password info to an open file
void write_password(FILE *fp) {
int t1;
//First write code for protection mode
fputc(protection_method,fp);
//If it was 0, we're done!
if(!protection_method) return;
//Otherwise, let's fiddle with the 15 byte password and output
str_cpy(work_area,magic_code);
for(t1=0;t1<15;t1++)
work_area[t1]^=(password[t1]^0x8D)+0x12+protection_method;
fwrite(work_area,1,15,fp);
//Done!
}
//Read password info from an open file
void read_password(FILE *fp) {
int t1;
//First get code for protection mode
protection_method=fgetc(fp);
//If it was 0, we're done!
if(!protection_method) {
password[0]=0;
return;
}
//Otherwise, let's read the 15 byte code and fiddle for the password
fread(work_area,1,15,fp);
for(t1=0;t1<15;t1++) {
work_area[t1]^=magic_code[t1];
work_area[t1]-=0x12+protection_method;
work_area[t1]^=0x8D;
}
str_cpy(password,work_area);
//Done!
}
//Get xor code for the current password
unsigned char get_pw_xor_code(void) {
int work=85;//Start with 85... (01010101)
int t1;
if(protection_method==0) return 0;
//Clear pw after first null
for(t1=str_len(password);t1<16;t1++)
password[t1]=0;
for(t1=0;t1<15;t1++) {
//For each byte, roll once to the left and xor in pw byte if it
//is an odd character, or add in pw byte if it is an even character.
work<<=1;
if(work>255) work^=257;//Wraparound from roll
if(t1&1) {
work+=password[t1];//Add (even byte)
if(work>255) work^=257;//Wraparound from add
}
else work^=password[t1];//XOR (odd byte);
}
//To factor in protection method, add it in and roll one last time
work+=protection_method;
if(work>255) work^=257;
work<<=1;
if(work>255) work^=257;
//Can't be 0-
if(work==0) work=86;//(01010110)
//Done!
return (unsigned char)work;
}
//Checks an inputted password against the current password. Gives error
//and returns non-0 if wrong.
char check_pw(void) {
char temp[16]="";
if(protection_method==0) return 0;
if(password[0]==0) return 0;
set_context(95);
retry:
save_screen(current_pg_seg);
draw_window_box(16,12,44,14,current_pg_seg,143,128,135);
write_string("Password:",18,13,143,current_pg_seg);
if(intake(temp,15,28,13,current_pg_seg,142,1,0,1)==27) {
restore_screen(current_pg_seg);
pop_context();
return -1;
}
restore_screen(current_pg_seg);
if(str_cmp(temp,password)) {
//Error
if(error("Invalid password",0,26,current_pg_seg,0x1001)==2)
goto retry;//Chose RETRY.
pop_context();
return -1;
}
//Correct.
pop_context();
return 0;
}
//After checking password if one is present, we allow editing of the
//password and protection method.
//--------------------------------------
//
// ( ) No protection
// ( ) No-save protection (anti-ripoff)
// ( ) No-edit protection
// ( ) No-play protection
//
// Password: ***************_
//
// _OK_ _Cancel_
//
//--------------------------------------
char pdi_types[4]={ DE_RADIO,DE_INPUT,DE_BUTTON,DE_BUTTON };
char pdi_xs[4]={ 2,2,7,20 };
char pdi_ys[4]={ 2,7,9,9 };
char far *pdi_strs[4]={ "No protection\nNo-save protection (anti-ripoff)\n\
No-edit protection\nNo-play protection","Password: ","OK","Cancel" };
int pdi_p1s[4]={ 4,15,0,-1 };
int pdi_p2s[2]={ 32,0 };
void far *pdi_storage[2]={ NULL,NULL };
dialog pdi={
20,5,59,16,"Password protection",4,
pdi_types,
pdi_xs,
pdi_ys,
pdi_strs,
pdi_p1s,
pdi_p2s,
pdi_storage,0 };
void password_dialog(void) {
int p_m=protection_method;
char temp[16];
if(check_pw()) return;
set_context(95);
pdi_storage[0]=&p_m;
pdi_storage[1]=temp;
str_cpy(temp,password);
if(run_dialog(&pdi,current_pg_seg)) {
pop_context();
return;//No changy
}
if(temp[0]==0) p_m=NO_PROTECTION;//No protection w/o a password!
str_cpy(password,temp);
protection_method=p_m;
pop_context();
return;
}