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/*
* ----------------------------------------------------------------------------
* "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
* ----------------------------------------------------------------------------
*/
/*
* Ported from FreeBSD to Linux, only minimal changes. --marekm
*/
/*
* Adapted from shadow-19990607 by Tudor Bosman, tudorb@jm.nu
*/
#include "lib.h"
#include "safe-memset.h"
#include "str.h"
#include "md5.h"
#include "password-scheme.h"
static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static char magic[] = "$1$"; /*
* This string is magic for
* this algorithm. Having
* it this way, we can get
* get better later on
*/
static void
to64(string_t *str, unsigned long v, int n)
{
while (--n >= 0) {
str_append_c(str, itoa64[v&0x3f]);
v >>= 6;
}
}
/*
* UNIX password
*
* Use MD5 for what it is best at...
*/
const char *password_generate_md5_crypt(const char *pw, const char *salt)
{
const char *sp,*ep;
unsigned char final[MD5_RESULTLEN];
int sl,pl,i,j;
struct md5_context ctx,ctx1;
unsigned long l;
string_t *passwd;
size_t pw_len = strlen(pw);
/* Refine the Salt first */
sp = salt;
/* If it starts with the magic string, then skip that */
if (strncmp(sp, magic, sizeof(magic)-1) == 0)
sp += sizeof(magic)-1;
/* It stops at the first '$', max 8 chars */
for(ep=sp;*ep != '\0' && *ep != '$' && 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_update(&ctx,pw,pw_len);
/* Then our magic string */
md5_update(&ctx,magic,sizeof(magic)-1);
/* Then the raw salt */
md5_update(&ctx,sp,sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
md5_init(&ctx1);
md5_update(&ctx1,pw,pw_len);
md5_update(&ctx1,sp,sl);
md5_update(&ctx1,pw,pw_len);
md5_final(&ctx1,final);
for(pl = pw_len; pl > 0; pl -= MD5_RESULTLEN)
md5_update(&ctx,final,pl>MD5_RESULTLEN ? MD5_RESULTLEN : pl);
/* Don't leave anything around in vm they could use. */
safe_memset(final, 0, sizeof(final));
/* Then something really weird... */
for (j=0,i = pw_len; i != 0; i >>= 1)
if ((i&1) != 0)
md5_update(&ctx, final+j, 1);
else
md5_update(&ctx, pw+j, 1);
/* Now make the output string */
passwd = t_str_new(sl + 64);
str_append(passwd, magic);
str_append_data(passwd, sp, sl);
str_append_c(passwd, '$');
md5_final(&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) != 0)
md5_update(&ctx1,pw,pw_len);
else
md5_update(&ctx1,final,MD5_RESULTLEN);
if((i % 3) != 0)
md5_update(&ctx1,sp,sl);
if((i % 7) != 0)
md5_update(&ctx1,pw,pw_len);
if((i & 1) != 0)
md5_update(&ctx1,final,MD5_RESULTLEN);
else
md5_update(&ctx1,pw,pw_len);
md5_final(&ctx1,final);
}
l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(passwd,l,4);
l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(passwd,l,4);
l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(passwd,l,4);
l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(passwd,l,4);
l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(passwd,l,4);
l = final[11] ; to64(passwd,l,2);
/* Don't leave anything around in vm they could use. */
safe_memset(final, 0, sizeof(final));
return str_c(passwd);
}
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