BSD 1 development

[unix-history] / s1 / passwd.c

/*
* enter a password in the password file
* this program should be suid with owner
* with an owner with write permission on /etc/passwd
*/
char    *tfile  { "/usr/adm/ptmp" };
char    *pfile  { "/etc/passwd" };
char    *pw;
char    pwbuf[10];
int     ttybuf[3];
int     tbuf[259];
int     pbuf[259];

main(argc, argv)
char *argv[];
{
       register u, c;
       register char *p;
       int exitt();
       int v;
       char x;

       if(argc < 2) {
               write(2, "Usage: passwd user [ password ]\n", 32);
               goto bex;
       }
       if(argc == 2) {
               signal(1, &exitt);
               signal(2, &exitt);
               signal(3, &exitt);
               gtty(0, ttybuf);
               ttybuf[2] =& ~010;
               stty(0, ttybuf);
again:
               write(2, "Password: ", 10);
               p = pwbuf;
               for(;;) {
                       if(read(0, p, 1) != 1)
                               break;
                       if(*p == '\n')
                               break;
                       if(p < pwbuf+9)
                               p++;
               }
               *p = 0;
               write(2, "\nAgain: ", 8);
               p = pwbuf;
               for (;;) {
                       if (read(0, &x, 1) != 1 || x == '\n')
                               break;
                       if (*p++ != x) {
xxx:
                               while (read(0, &x, 1) == 1 && x != '\n')
                                       continue;
                               write(2, "\nThose weren't the same\n", 24);
                               goto again;
                       }
               }
               if (*p != 0)
                       goto xxx;
               ttybuf[2] =| 010;
               stty(0, ttybuf);
               write(2, "\n", 1);
               pw = pwbuf;
       } else
               pw = argv[2];
       signal(1, 1);
       signal(2, 1);
       signal(3, 1);

       if(stat(tfile, tbuf+20) >= 0) {
               write(2, "Temporary file busy -- try again\n", 33);
               goto bex;
       }
       tbuf[0] = creat(tfile, 0600);
       if(tbuf[0] < 0) {
               write(2, "Cannot create temporary file\n", 29);
               goto bex;
       }
       pbuf[0] = open(pfile, 0);
       if(pbuf[0] < 0) {
               write(2, "Cannot open /etc/passwd\n", 25);
               goto out;
       }
       goto l1;

/*
* skip to beginning of next line
*/

skip:
       while(c != '\n') {
               if(c < 0)
                       goto ill;
               c = getc(pbuf);
               putc(c, tbuf);
       }

/*
* compare user names
*/

l1:
       c = getc(pbuf);
       putc(c, tbuf);
       if(c < 0) {
               write(2, "User name not found in password file\n", 37);
               goto out;
       }
       p = argv[1];
       while(c != ':') {
               if(*p++ != c)
                       goto skip;
               c = getc(pbuf);
               putc(c, tbuf);
       }
       if(*p)
               goto skip;
/*
* skip old password
*/
       do {
               c = getc(pbuf);
               if(c < 0)
                       goto ill;
       } while(c != ':');

/*
* copy in new password
*/
       p = pw;
       for(c=0; c<9; c++)
               if(*p++ == 0)
                       break;
       *--p = 0;
       if(p != pw)
               p = crypt(pw);
       while(*p)
               putc(*p++, tbuf);
       putc(':', tbuf);

/*
* validate uid and gid
*/

       u = 0;
       do {
               c = getc(pbuf);
               putc(c, tbuf);
               if(c >= '0' && c <= '9')
                       u = u*10 + c-'0';
               if(c < 0)
                       goto ill;
       } while(c != ':');
       v = 0;
       do {
               c = getc(pbuf);
               putc(c, tbuf);
               if(c >= '0' && c <= '9')
                       v = v*10 + c-'0';
               if(c < 0)
                       goto ill;
       } while(c != ':');
       c = getuid();
       if(c == 0)
               goto ok;
       if(c == ((v<<8) | u))
               goto ok;
       if((c&0377) == 0 && ((c>>8)&0377) == v)
               goto ok;
       write(2, "Permission denied\n", 18);
       goto out;
ok:

/*
* copy out and back
*/

       for(;;) {
               c = getc(pbuf);
               if(c < 0) {
                       fflush(tbuf);
                       close(pbuf[0]);
                       close(tbuf[0]);
                       tbuf[0] = open(tfile, 0);
                       if(tbuf[0] < 0) {
                               write(2, "Urk\n", 4);
                               goto out;
                       }
                       pbuf[0] = creat(pfile, 0644);
                       if(pbuf[0] < 0) {
                               write(2, "Cannot create /etc/passwd\n", 27);
                               goto out;
                       }
                       while((c = read(tbuf[0], tbuf+1, 512)) > 0)
                               write(pbuf[0], tbuf+1, c);
                       unlink(tfile);
                       exit(0);
               }
               putc(c, tbuf);
       }

ill:
       write(2, "Password file illformed\n", 24);

out:
       unlink(tfile);

bex:
       exit(1);
}

exitt()
{
       ttybuf[2] =| 010;
       stty(0, ttybuf);
       write(2, "\n", 1);
       exit(1);
}