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/*-
* Copyright (c) 2003 Poul-Henning Kamp
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <inttypes.h>
#include <md5.h>
#include <string.h>
/*
* UNIX password
*/
static char *_crypt_to64(char *s, uint32_t v, int n)
{
static const char itoa64[64] = "./0123456789"
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
while (--n >= 0) {
*s++ = itoa64[v & 0x3f];
v >>= 6;
}
return s;
}
char *crypt_md5(const char *pw, const char *salt)
{
MD5_CTX ctx, ctx1;
unsigned long l;
int sl, pl;
uint32_t i;
uint8_t final[MD5_SIZE];
const char *sp;
static char passwd[120]; /* Output buffer */
static const char magic[] = "$1$";
char *p;
const int magic_len = sizeof magic - 1;
int pwlen = strlen(pw);
/* Refine the Salt first */
sp = salt;
/* If it starts with the magic string, then skip that */
if (!strncmp(sp, magic, magic_len))
sp += magic_len;
/* Compute the salt length:
it stops at the first '$', max 8 chars */
for (sl = 0; sl < 8 && sp[sl] && sp[sl] != '$'; sl++) ;
MD5Init(&ctx);
/* The password first, since that is what is most unknown */
MD5Update(&ctx, pw, pwlen);
/* Then our magic string */
MD5Update(&ctx, magic, magic_len);
/* Then the raw salt */
MD5Update(&ctx, sp, sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
MD5Init(&ctx1);
MD5Update(&ctx1, pw, pwlen);
MD5Update(&ctx1, sp, sl);
MD5Update(&ctx1, pw, pwlen);
MD5Final(final, &ctx1);
for (pl = pwlen; pl > 0; pl -= MD5_SIZE)
MD5Update(&ctx, final, pl > MD5_SIZE ? MD5_SIZE : pl);
/* Don't leave anything around in vm they could use. */
memset(final, 0, sizeof final);
/* Then something really weird... */
for (i = pwlen; i; i >>= 1)
if (i & 1)
MD5Update(&ctx, final, 1);
else
MD5Update(&ctx, pw, 1);
/* Now make the output string */
p = passwd;
memcpy(p, magic, magic_len);
p += magic_len;
memcpy(p, sp, sl);
p += sl;
*p++ = '$';
MD5Final(final, &ctx);
/*
* 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++) {
MD5Init(&ctx1);
if (i & 1)
MD5Update(&ctx1, pw, pwlen);
else
MD5Update(&ctx1, final, MD5_SIZE);
if (i % 3)
MD5Update(&ctx1, sp, sl);
if (i % 7)
MD5Update(&ctx1, pw, pwlen);
if (i & 1)
MD5Update(&ctx1, final, MD5_SIZE);
else
MD5Update(&ctx1, pw, pwlen);
MD5Final(final, &ctx1);
}
l = (final[0] << 16) | (final[6] << 8) | final[12];
p = _crypt_to64(p, l, 4);
l = (final[1] << 16) | (final[7] << 8) | final[13];
p = _crypt_to64(p, l, 4);
l = (final[2] << 16) | (final[8] << 8) | final[14];
p = _crypt_to64(p, l, 4);
l = (final[3] << 16) | (final[9] << 8) | final[15];
p = _crypt_to64(p, l, 4);
l = (final[4] << 16) | (final[10] << 8) | final[5];
p = _crypt_to64(p, l, 4);
l = final[11];
p = _crypt_to64(p, l, 2);
*p = '\0';
/* Don't leave anything around in vm they could use. */
memset(final, 0, sizeof final);
return passwd;
}
#ifdef TEST
#include <stdio.h>
int main(int argc, char *argv[])
{
int i;
for (i = 2; i < argc; i += 2) {
puts(crypt_md5(argv[i], argv[i - 1]));
}
return 0;
}
#endif
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