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freebsd_crypt.c
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freebsd_crypt.c
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/* From: http://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libcrypt/crypt-md5.c?rev=1.12
* ----------------------------------------------------------------------------
* "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
* ----------------------------------------------------------------------------
*/
#include <sys/cdefs.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <tomcrypt.h>
#include <err.h>
#define MD5_SIZE 16
static char itoa64[] = /* 0 ... 63 => ascii - 64 */
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
void
_crypt_to64(char *s, u_long v, int n)
{
while (--n >= 0) {
*s++ = itoa64[v&0x3f];
v >>= 6;
}
}
/*
* UNIX password
*/
char *
crypt(const char *pw, const char *salt_orig)
{
hash_state ctx,ctx1;
unsigned long l;
int sl, pl;
u_int i;
u_char final[MD5_SIZE];
static const char *sp, *ep;
static char passwd[120], *p;
static const char *magic = "$1$"; /*
* This string is magic for
* this algorithm. Having
* it this way, we can get
* better later on.
*/
char *salt = m_strdup(salt_orig);
/* Refine the Salt first */
sp = salt;
/* If it starts with the magic string, then skip that */
if(!strncmp(sp, magic, strlen(magic)))
sp += strlen(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;
md5_init(&ctx);
/* The password first, since that is what is most unknown */
md5_process(&ctx, (const u_char *)pw, strlen(pw));
/* Then our magic string */
md5_process(&ctx, (const u_char *)magic, strlen(magic));
/* Then the raw salt */
md5_process(&ctx, (const u_char *)sp, (u_int)sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
md5_init(&ctx1);
md5_process(&ctx1, (const u_char *)pw, strlen(pw));
md5_process(&ctx1, (const u_char *)sp, (u_int)sl);
md5_process(&ctx1, (const u_char *)pw, strlen(pw));
md5_done(&ctx1, final);
for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE)
md5_process(&ctx, (const u_char *)final,
(u_int)(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 = strlen(pw); i; i >>= 1)
if(i & 1)
md5_process(&ctx, (const u_char *)final, 1);
else
md5_process(&ctx, (const u_char *)pw, 1);
/* Now make the output string */
strcpy(passwd, magic);
strncat(passwd, sp, (u_int)sl);
strcat(passwd, "$");
md5_done(&ctx, final);
/*
* 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++) {
md5_init(&ctx1);
if(i & 1)
md5_process(&ctx1, (const u_char *)pw, strlen(pw));
else
md5_process(&ctx1, (const u_char *)final, MD5_SIZE);
if(i % 3)
md5_process(&ctx1, (const u_char *)sp, (u_int)sl);
if(i % 7)
md5_process(&ctx1, (const u_char *)pw, strlen(pw));
if(i & 1)
md5_process(&ctx1, (const u_char *)final, MD5_SIZE);
else
md5_process(&ctx1, (const u_char *)pw, strlen(pw));
md5_done(&ctx1, final);
}
p = passwd + strlen(passwd);
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. */
memset(final, 0, sizeof(final));
return passwd;
}