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/* $OpenBSD: str2key.c,v 1.6 1998/06/22 15:22:27 beck Exp $ */
/* $KTH: str2key.c,v 1.10 1997/03/23 03:53:19 joda Exp $ */
/* This defines the Andrew string_to_key function. It accepts a password
* string as input and converts its via a one-way encryption algorithm to a DES
* encryption key. It is compatible with the original Andrew authentication
* service password database.
*/
#include "krb_locl.h"
static void
mklower(char *s)
{
for (; s[0] != '\0'; s++)
if ('A' <= *s && *s <= 'Z')
*s = *s - 'A' + 'a';
}
/*
* Short passwords, i.e 8 characters or less.
*/
static void
afs_cmu_StringToKey (char *str, char *cell, des_cblock *key)
{
char password[8+1]; /* crypt is limited to 8 chars anyway */
int i;
int passlen;
memset(key, 0, sizeof(key));
memset(password, 0, sizeof(password));
strncpy (password, cell, 8);
password[8] = '\0';
passlen = strlen (str);
if (passlen > 8) passlen = 8;
for (i=0; i<passlen; i++)
password[i] = str[i] ^ cell[i]; /* make sure cell is zero padded */
for (i=0; i<8; i++)
if (password[i] == '\0') password[i] = 'X';
/* crypt only considers the first 8 characters of password but for some
reason returns eleven characters of result (plus the two salt chars). */
strncpy((char *)key, (char *)des_crypt(password, "#~") + 2, sizeof(des_cblock));
/* parity is inserted into the LSB so leftshift each byte up one bit. This
allows ascii characters with a zero MSB to retain as much significance
as possible. */
{ char *keybytes = (char *)key;
unsigned int temp;
for (i = 0; i < 8; i++) {
temp = (unsigned int) keybytes[i];
keybytes[i] = (unsigned char) (temp << 1);
}
}
des_fixup_key_parity (key);
}
/*
* Long passwords, i.e 9 characters or more.
*/
static void
afs_transarc_StringToKey (char *str, char *cell, des_cblock *key)
{
des_key_schedule schedule;
des_cblock temp_key;
des_cblock ivec;
char password[512];
int passlen;
strncpy (password, str, sizeof(password));
password[sizeof(password)-1] = '\0';
if ((passlen = strlen (password)) < sizeof(password)-1)
strncat (password, cell, sizeof(password)-passlen);
if ((passlen = strlen(password)) > sizeof(password)) passlen = sizeof(password);
memcpy(&ivec, "kerberos", 8);
memcpy(&temp_key, "kerberos", 8);
des_fixup_key_parity (&temp_key);
des_key_sched (&temp_key, schedule);
des_cbc_cksum ((des_cblock *)password, &ivec, passlen, schedule, &ivec);
memcpy(&temp_key, &ivec, 8);
des_fixup_key_parity (&temp_key);
des_key_sched (&temp_key, schedule);
des_cbc_cksum ((des_cblock *)password, key, passlen, schedule, &ivec);
des_fixup_key_parity (key);
}
void
afs_string_to_key(char *str, char *cell, des_cblock *key)
{
char realm[REALM_SZ+1];
strncpy(realm, cell, REALM_SZ);
realm[REALM_SZ] = 0;
mklower(realm);
if (strlen(str) > 8)
afs_transarc_StringToKey (str, realm, key);
else
afs_cmu_StringToKey (str, realm, key);
}
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