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/* $OpenBSD: md5crypt.c,v 1.17 2014/04/03 15:55:29 beck Exp $ */
/*
* Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* If we meet some day, and you think this stuff is worth it, you
* can buy me a beer in return. Poul-Henning Kamp
*/
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <md5.h>
#include <string.h>
static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static void to64(char *, u_int32_t, int);
static void
to64(char *s, u_int32_t v, int n)
{
while (--n >= 0) {
*s++ = itoa64[v&0x3f];
v >>= 6;
}
}
/*
* UNIX password
*
* Use MD5 for what it is best at...
*/
char *md5crypt(const char *pw, const char *salt);
char *
md5crypt(const char *pw, const char *salt)
{
/*
* This string is the magic for this algorithm.
* Having it this way, we can get better later on.
*/
static unsigned char *magic = (unsigned char *)"$1$";
static char passwd[120], *p;
static const unsigned char *sp,*ep;
unsigned char final[16];
int sl,pl,i;
MD5_CTX ctx,ctx1;
u_int32_t l;
/* Refine the salt first */
sp = (const unsigned char *)salt;
/* If it starts with the magic string, then skip that */
if(!strncmp((const char *)sp,(const char *)magic,strlen((const char *)magic)))
sp += strlen((const char *)magic);
/* It stops at the first '$', max 8 chars */
for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
continue;
/* get the length of the true salt */
sl = ep - sp;
MD5Init(&ctx);
/* The password first, since that is what is most unknown */
MD5Update(&ctx,(const unsigned char *)pw,strlen(pw));
/* Then our magic string */
MD5Update(&ctx,magic,strlen((const char *)magic));
/* Then the raw salt */
MD5Update(&ctx,sp,sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
MD5Init(&ctx1);
MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
MD5Update(&ctx1,sp,sl);
MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
MD5Final(final,&ctx1);
for(pl = strlen(pw); pl > 0; pl -= 16)
MD5Update(&ctx,final,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 = strlen(pw); i ; i >>= 1)
if(i&1)
MD5Update(&ctx, final, 1);
else
MD5Update(&ctx, (const unsigned char *)pw, 1);
/* Now make the output string */
snprintf(passwd, sizeof(passwd), "%s%.*s$", (char *)magic,
sl, (const char *)sp);
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...
* On a modern machine, with possible GPU optimization,
* this will run a lot faster than that.
*/
for(i=0;i<1000;i++) {
MD5Init(&ctx1);
if(i & 1)
MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
else
MD5Update(&ctx1,final,16);
if(i % 3)
MD5Update(&ctx1,sp,sl);
if(i % 7)
MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
if(i & 1)
MD5Update(&ctx1,final,16);
else
MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
MD5Final(final,&ctx1);
}
p = passwd + strlen(passwd);
l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p,l,4); p += 4;
l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p,l,4); p += 4;
l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p,l,4); p += 4;
l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p,l,4); p += 4;
l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p,l,4); p += 4;
l = final[11] ; to64(p,l,2); p += 2;
*p = '\0';
/* Don't leave anything around in vm they could use. */
memset(final, 0, sizeof final);
return passwd;
}
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