NetBSD/lib/libcrypt/md5crypt.c

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/* $NetBSD: md5crypt.c,v 1.3 2000/12/03 13:01:37 ad Exp $ */
/*
* ----------------------------------------------------------------------------
* "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
* ----------------------------------------------------------------------------
*
* 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)
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__RCSID("$NetBSD: md5crypt.c,v 1.3 2000/12/03 13:01:37 ad Exp $");
#endif /* not lint */
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <md5.h>
#include <string.h>
#define MD5_MAGIC "$1$"
#define MD5_MAGIC_LEN 3
char *__md5crypt(const char *pw, const char *salt); /* XXX */
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;
}
}
/*
* MD5 password encryption.
*/
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 */
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if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
sp += MD5_MAGIC_LEN;
/* It stops at the first '$', max 8 chars */
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for (ep = sp; *ep != '\0' && *ep != '$' && 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, pwl);
/* Then our magic string */
MD5Update(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
/* Then the raw salt */
MD5Update(&ctx, (const unsigned char *)sp, sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
MD5Init(&ctx1);
MD5Update(&ctx1, (const unsigned char *)pw, pwl);
MD5Update(&ctx1, (const unsigned char *)sp, sl);
MD5Update(&ctx1, (const unsigned char *)pw, pwl);
MD5Final(final, &ctx1);
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for (pl = pwl; pl > 0; pl -= 16)
MD5Update(&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)
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if ((i & 1) != 0)
MD5Update(&ctx, final, 1);
else
MD5Update(&ctx, (const unsigned char *)pw, 1);
/* Now make the output string */
memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
strncpy(passwd + MD5_MAGIC_LEN, sp, sl);
strcat(passwd, "$");
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...
*/
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for (i = 0; i < 1000; i++) {
MD5Init(&ctx1);
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if ((i & 1) != 0)
MD5Update(&ctx1, (const unsigned char *)pw, pwl);
else
MD5Update(&ctx1, final, 16);
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if ((i % 3) != 0)
MD5Update(&ctx1, (const unsigned char *)sp, sl);
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if ((i % 7) != 0)
MD5Update(&ctx1, (const unsigned char *)pw, pwl);
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if ((i & 1) != 0)
MD5Update(&ctx1, final, 16);
else
MD5Update(&ctx1, (const unsigned char *)pw, pwl);
MD5Final(final, &ctx1);
}
p = passwd + sl + MD5_MAGIC_LEN + 1;
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);
}