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md5crypt.c
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md5crypt.c
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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* Cherokee
*
* Authors:
* Alvaro Lopez Ortega <alvaro@alobbs.com>
*
* Copyright (C) 2001-2010 Alvaro Lopez Ortega
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include "common-internal.h"
#include "md5.h"
#include "md5crypt.h"
#include "util.h"
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@login.dknet.dk> 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
* ----------------------------------------------------------------------------
*/
/* 0 ... 63 => ascii - 64 */
static unsigned char itoa64[] =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static char *
to64 (char *tmp, unsigned long v, int n)
{
/* We do know 'tmp' is 5 bytes long */
char *s = tmp;
memset (tmp, 0, 5);
if (n > 4)
return NULL;
while (--n >= 0) {
*s++ = itoa64[v&0x3f];
v >>= 6;
}
return tmp;
}
char *
md5_crypt(const char *pw, const char *salt, const char *magic, char passwd[MD5CRYPT_PASSWD_LEN])
{
char salt_copy[9], *p;
const char *sp, *ep;
unsigned char final[16];
int sl, pl, i, j;
struct MD5Context ctx, ctx1;
unsigned long l;
cuint_t magic_len;
char to64_buf[5];
/* Refine the salt first. It's possible we were given an already-hashed
* string as the salt argument, so extract the actual salt value from it
* if so. Otherwise just use the string up to the first '$' as the salt.
*/
sp = salt;
/* If it starts with the magic string, then skip that.
*/
magic_len = strlen (magic);
if (strncmp(sp, magic, magic_len) == 0)
sp += magic_len;
/* It stops at the first '$', max 8 chars
*/
for (ep = sp; *ep != '$'; ep++) {
if (*ep == '\0' || ep >= (sp + 8))
return NULL;
}
/* Get the length of the true salt
*/
sl = ep - sp;
/* Stash the salt */
memcpy(salt_copy, sp, sl);
salt_copy[sl] = '\0';
MD5Init(&ctx);
/* The password first, since that is what is most unknown */
MD5Update(&ctx, (unsigned char *)pw, strlen(pw));
/* Then our magic string */
MD5Update(&ctx, (unsigned char *)magic, magic_len);
/* Then the raw salt */
MD5Update(&ctx, (unsigned char *)sp, sl);
/* Then just as many characters of the MD5(pw, salt, pw) */
MD5Init(&ctx1);
MD5Update(&ctx1, (unsigned char *)pw, strlen(pw));
MD5Update(&ctx1, (unsigned char *)sp, sl);
MD5Update(&ctx1, (unsigned char *)pw, strlen(pw));
MD5Final(final, &ctx1);
for(pl = strlen(pw); pl > 0; pl -= 16)
MD5Update(&ctx, final, pl > 16 ? 16 : pl);
/* Don't leave anything around in vm they could use. */
memset(final, '\0', sizeof final);
/* Then something really weird... */
for (j = 0, i = strlen(pw); i != 0; i >>= 1) {
if (i & 1)
MD5Update(&ctx, final + j, 1);
else
MD5Update(&ctx, (unsigned char *)pw + j, 1);
}
/* Now make the output string
*/
snprintf(passwd, MD5CRYPT_PASSWD_LEN, "%s%s$", magic, salt_copy);
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, (unsigned char *)pw, strlen(pw));
else
MD5Update(&ctx1, final, 16);
if (i % 3)
MD5Update(&ctx1, (unsigned char *)sp, sl);
if (i % 7)
MD5Update(&ctx1, (unsigned char *)pw, strlen(pw));
if (i & 1)
MD5Update(&ctx1, final, 16);
else
MD5Update(&ctx1, (unsigned char *)pw, strlen(pw));
MD5Final(final, &ctx1);
}
p = passwd + strlen(passwd);
l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
strlcat (passwd, to64(to64_buf, l, 4), MD5CRYPT_PASSWD_LEN);
l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
strlcat (passwd, to64(to64_buf, l, 4), MD5CRYPT_PASSWD_LEN);
l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
strlcat (passwd, to64(to64_buf, l, 4), MD5CRYPT_PASSWD_LEN);
l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
strlcat (passwd, to64(to64_buf, l, 4), MD5CRYPT_PASSWD_LEN);
l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
strlcat (passwd, to64(to64_buf, l, 4), MD5CRYPT_PASSWD_LEN);
l = final[11] ;
strlcat (passwd, to64(to64_buf, l, 2), MD5CRYPT_PASSWD_LEN);
/* Don't leave anything around in vm they could use.
*/
memset(final, 0, sizeof(final));
memset(salt_copy, 0, sizeof(salt_copy));
memset(&ctx, 0, sizeof(ctx));
memset(&ctx1, 0, sizeof(ctx1));
(void) to64(to64_buf, 0, 4);
return passwd;
}