minix/lib/other/crypt.c
2005-04-21 14:53:53 +00:00

115 lines
2.3 KiB
C
Executable file

/* crypt() - one-way password encryption function Author: Kees J. Bot
* 7 Feb 1994
* This routine does not encrypt anything, it uses the pwdauth
* program to do the hard work.
*/
#define nil ((void*)0)
#define pipe _pipe
#define fork _fork
#define close _close
#define dup2 _dup2
#define execl _execl
#define read _read
#define _exit __exit
#define write _write
#define waitpid _waitpid
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <stdarg.h>
#include <sys/wait.h>
/* Set-uid root program to read /etc/shadow or encrypt passwords. */
static char PWDAUTH[] = "/usr/lib/pwdauth";
#define LEN 1024
static void tell(const char *s0, ...)
{
va_list ap;
const char *s;
va_start(ap, s0);
s= s0;
while (s != nil) {
(void) write(2, s, strlen(s));
s= va_arg(ap, const char *);
}
va_end(ap);
}
char *crypt(const char *key, const char *salt)
{
pid_t pid;
int status;
int pfd[2];
static char pwdata[LEN];
char *p= pwdata;
const char *k= key;
const char *s= salt;
int n;
/* Fill pwdata[] with the key and salt. */
while ((*p++ = *k++) != 0) if (p == pwdata+LEN-1) goto fail;
while ((*p++ = *s++) != 0) if (p == pwdata+LEN-0) goto fail;
if (pipe(pfd) < 0) goto fail;
/* Prefill the pipe. */
(void) write(pfd[1], pwdata, p - pwdata);
switch ((pid= fork())) {
case -1:
close(pfd[0]);
close(pfd[1]);
goto fail;
case 0:
/* Connect both input and output to the pipe. */
if (pfd[0] != 0) {
dup2(pfd[0], 0);
close(pfd[0]);
}
if (pfd[1] != 1) {
dup2(pfd[1], 1);
close(pfd[1]);
}
execl(PWDAUTH, PWDAUTH, (char *) nil);
tell("crypt(): ", PWDAUTH, ": ", strerror(errno), "\r\n",
(char *) nil);
/* No pwdauth? Fail! */
(void) read(0, pwdata, LEN);
_exit(1);
}
close(pfd[1]);
status= -1;
while (waitpid(pid, &status, 0) == -1 && errno == EINTR) {}
if (status != 0) {
close(pfd[0]);
goto fail;
}
/* Read and return the result. Check if it contains exactly one
* string.
*/
n= read(pfd[0], pwdata, LEN);
close(pfd[0]);
if (n < 0) goto fail;
p = pwdata + n;
n = 0;
while (p > pwdata) if (*--p == 0) n++;
if (n != 1) goto fail;
return pwdata;
fail:
pwdata[0] = salt[0] ^ 1; /* make result != salt */
pwdata[1] = 0;
return pwdata;
}
/*
* $PchId: crypt.c,v 1.5 1996/04/11 07:46:11 philip Exp $
*/