/* $NetBSD: md5crypt.c,v 1.16 2024/07/23 22:37:11 riastradh Exp $ */
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <
[email protected]> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* from FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp
* via OpenBSD: md5crypt.c,v 1.9 1997/07/23 20:58:27 kstailey Exp
*
*/
#include <sys/cdefs.h>
#if !defined(lint)
__RCSID("$NetBSD: md5crypt.c,v 1.16 2024/07/23 22:37:11 riastradh Exp $");
#endif /* not lint */
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <md5.h>
#include "crypt.h"
#define MD5_MAGIC "$1$"
#define MD5_MAGIC_LEN 3
#define INIT(x) MD5Init((x))
#define UPDATE(x, b, l) MD5Update((x), (b), (l))
#define FINAL(v, x) MD5Final((v), (x))
/*
* MD5 password encryption.
*/
crypt_private char *
__md5crypt(const char *pw, const char *salt)
{
static char passwd[120], *p;
const char *sp, *ep;
unsigned char final[16];
unsigned int i, sl, pwl;
MD5_CTX ctx, ctx1;
u_int32_t l;
int pl;
pwl = strlen(pw);
/* Refine the salt first */
sp = salt;
/* If it starts with the magic string, then skip that */
if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
sp += MD5_MAGIC_LEN;
/* It stops at the first '$', max 8 chars */
for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++)
continue;
/* get the length of the true salt */
sl = ep - sp;
INIT(&ctx);
/* The password first, since that is what is most unknown */
UPDATE(&ctx, (const unsigned char *)pw, pwl);
/* Then our magic string */
UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
/* Then the raw salt */
UPDATE(&ctx, (const unsigned char *)sp, sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
INIT(&ctx1);
UPDATE(&ctx1, (const unsigned char *)pw, pwl);
UPDATE(&ctx1, (const unsigned char *)sp, sl);
UPDATE(&ctx1, (const unsigned char *)pw, pwl);
FINAL(final, &ctx1);
for (pl = pwl; pl > 0; pl -= 16)
UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl));
/* Don't leave anything around in vm they could use. */
memset(final, 0, sizeof(final));
/* Then something really weird... */
for (i = pwl; i != 0; i >>= 1)
if ((i & 1) != 0)
UPDATE(&ctx, final, 1);
else
UPDATE(&ctx, (const unsigned char *)pw, 1);
/* Now make the output string */
memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1);
strlcat(passwd, "$", sizeof(passwd));
FINAL(final, &ctx);
/* memset(&ctx, 0, sizeof(ctx)); done by MD5Final() */
/*
* And now, just to make sure things don't run too fast. On a 60 MHz
* Pentium this takes 34 msec, so you would need 30 seconds to build
* a 1000 entry dictionary...
*/
for (i = 0; i < 1000; i++) {
INIT(&ctx1);
if ((i & 1) != 0)
UPDATE(&ctx1, (const unsigned char *)pw, pwl);
else
UPDATE(&ctx1, final, 16);
if ((i % 3) != 0)
UPDATE(&ctx1, (const unsigned char *)sp, sl);
if ((i % 7) != 0)
UPDATE(&ctx1, (const unsigned char *)pw, pwl);
if ((i & 1) != 0)
UPDATE(&ctx1, final, 16);
else
UPDATE(&ctx1, (const unsigned char *)pw, pwl);
FINAL(final, &ctx1);
}
/* memset(&ctx1, 0, sizeof(ctx1)); done by MD5Final() */
p = passwd + sl + MD5_MAGIC_LEN + 1;
l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; __crypt_to64(p,l,4); p += 4;
l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; __crypt_to64(p,l,4); p += 4;
l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; __crypt_to64(p,l,4); p += 4;
l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; __crypt_to64(p,l,4); p += 4;
l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; __crypt_to64(p,l,4); p += 4;
l = final[11] ; __crypt_to64(p,l,2); p += 2;
*p = '\0';
/* Don't leave anything around in vm they could use. */
explicit_memset(final, 0, sizeof(final));
return (passwd);
}
