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821f25ca1123bf81733524d8def4376c78ec33e1
heimdal/lib/krb5/crypto.c
Assar Westerlund 4ce9048b86 (krb5_verify_checksum): rename C -> cksum to be consistent 
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@5553 ec53bebd-3082-4978-b11e-865c3cabbd6b
1999-03-16 13:31:27 +00:00

2136 lines
49 KiB
C
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/*
* Copyright (c) 1997, 1998, 1999 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Kungliga Tekniska
* Högskolan and its contributors.
*
* 4. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb5_locl.h"
RCSID("$Id$");
#undef CRYPTO_DEBUG
#ifdef CRYPTO_DEBUG
static void krb5_crypto_debug(krb5_context, int, size_t, krb5_keyblock*);
#endif
struct key_data {
krb5_keyblock *key;
krb5_data *schedule;
};
struct key_usage {
unsigned usage;
struct key_data key;
};
struct krb5_crypto_data {
struct encryption_type *et;
struct key_data key;
int num_key_usage;
struct key_usage *key_usage;
};
#define CRYPTO_ETYPE(C) ((C)->et->type)
/* bits for `flags' below */
#define F_KEYED 1 /* checksum is keyed */
#define F_CPROOF 2 /* checksum is collision proof */
#define F_DERIVED 4 /* uses derived keys */
#define F_VARIANT 8 /* uses `variant' keys (6.4.3) */
struct salt_type {
krb5_salttype type;
const char *name;
krb5_error_code (*string_to_key)(krb5_context, krb5_enctype, krb5_data,
krb5_salt, krb5_keyblock*);
};
struct key_type {
krb5_keytype type; /* XXX */
const char *name;
size_t bits;
size_t size;
size_t schedule_size;
#if 0
krb5_enctype best_etype;
#endif
void (*random_key)(krb5_context, krb5_keyblock*);
void (*schedule)(krb5_context, struct key_data *);
struct salt_type *string_to_key;
};
struct checksum_type {
krb5_cksumtype type;
const char *name;
size_t blocksize;
size_t checksumsize;
unsigned flags;
void (*checksum)(krb5_context, struct key_data*, void*, size_t, Checksum*);
krb5_error_code (*verify)(krb5_context, struct key_data*,
void*, size_t, Checksum*);
};
struct encryption_type {
krb5_enctype type;
const char *name;
size_t blocksize;
size_t confoundersize;
struct key_type *keytype;
struct checksum_type *cksumtype;
struct checksum_type *keyed_checksum;
unsigned flags;
void (*encrypt)(struct key_data *, void *, size_t, int);
};
#define ENCRYPTION_USAGE(U) (((U) << 8) | 0xAA)
#define INTEGRITY_USAGE(U) (((U) << 8) | 0x55)
#define CHECKSUM_USAGE(U) (((U) << 8) | 0x99)
static struct checksum_type *_find_checksum(krb5_cksumtype type);
static struct encryption_type *_find_enctype(krb5_enctype type);
static struct key_type *_find_keytype(krb5_keytype type);
static krb5_error_code _get_derived_key(krb5_context, krb5_crypto,
unsigned, struct key_data**);
static struct key_data *_new_derived_key(krb5_crypto crypto, unsigned usage);
/************************************************************
* *
************************************************************/
static void
DES_random_key(krb5_context context,
krb5_keyblock *key)
{
des_cblock *k = key->keyvalue.data;
do {
krb5_generate_random_block(k, sizeof(des_cblock));
des_set_odd_parity(k);
} while(des_is_weak_key(k));
}
static void
DES_schedule(krb5_context context,
struct key_data *key)
{
des_set_key(key->key->keyvalue.data, key->schedule->data);
}
static krb5_error_code
DES_string_to_key(krb5_context context,
krb5_enctype enctype,
krb5_data password,
krb5_salt salt,
krb5_keyblock *key)
{
char *s;
size_t len;
des_cblock tmp;
len = password.length + salt.saltvalue.length + 1;
s = malloc(len);
if(s == NULL)
return ENOMEM;
memcpy(s, password.data, password.length);
memcpy(s + password.length, salt.saltvalue.data, salt.saltvalue.length);
s[len - 1] = '\0';
des_string_to_key(s, &tmp);
key->keytype = enctype;
krb5_data_copy(&key->keyvalue, tmp, sizeof(tmp));
memset(&tmp, 0, sizeof(tmp));
memset(s, 0, len);
free(s);
return 0;
}
/* 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.
*/
/*
* Short passwords, i.e 8 characters or less.
*/
static void
DES_AFS3_CMU_string_to_key (krb5_data pw,
krb5_data cell,
des_cblock *key)
{
char password[8+1]; /* crypt is limited to 8 chars anyway */
int i;
for(i = 0; i < 8; i++) {
char c = ((i < pw.length) ? ((char*)pw.data)[i] : 0) ^
((i < cell.length) ? ((char*)cell.data)[i] : 0);
password[i] = c ? c : 'X';
}
password[8] = '\0';
memcpy(key, crypt(password, "#~") + 2, sizeof(des_cblock));
/* parity is inserted into the LSB so left shift each byte up one
bit. This allows ascii characters with a zero MSB to retain as
much significance as possible. */
for (i = 0; i < sizeof(des_cblock); i++)
((unsigned char*)key)[i] <<= 1;
des_set_odd_parity (key);
}
/*
* Long passwords, i.e 9 characters or more.
*/
static void
DES_AFS3_Transarc_string_to_key (krb5_data pw,
krb5_data cell,
des_cblock *key)
{
des_key_schedule schedule;
des_cblock temp_key;
des_cblock ivec;
char password[512];
size_t passlen;
memcpy(password, pw.data, min(pw.length, sizeof(password)));
if(pw.length < sizeof(password))
memcpy(password + pw.length,
cell.data, min(cell.length,
sizeof(password) - pw.length));
passlen = min(sizeof(password), pw.length + cell.length);
memcpy(&ivec, "kerberos", 8);
memcpy(&temp_key, "kerberos", 8);
des_set_odd_parity (&temp_key);
des_set_key (&temp_key, schedule);
des_cbc_cksum ((des_cblock *)password, &ivec, passlen, schedule, &ivec);
memcpy(&temp_key, &ivec, 8);
des_set_odd_parity (&temp_key);
des_set_key (&temp_key, schedule);
des_cbc_cksum ((des_cblock *)password, key, passlen, schedule, &ivec);
memset(&schedule, 0, sizeof(schedule));
memset(&temp_key, 0, sizeof(temp_key));
memset(&ivec, 0, sizeof(ivec));
memset(password, 0, sizeof(password));
des_set_odd_parity (key);
}
static krb5_error_code
DES_AFS3_string_to_key(krb5_context context,
krb5_enctype enctype,
krb5_data password,
krb5_salt salt,
krb5_keyblock *key)
{
des_cblock tmp;
if(password.length > 8)
DES_AFS3_Transarc_string_to_key(password, salt.saltvalue, &tmp);
else
DES_AFS3_CMU_string_to_key(password, salt.saltvalue, &tmp);
key->keytype = enctype;
krb5_data_copy(&key->keyvalue, tmp, sizeof(tmp));
memset(&key, 0, sizeof(key));
return 0;
}
static void
DES3_random_key(krb5_context context,
krb5_keyblock *key)
{
des_cblock *k = key->keyvalue.data;
do {
krb5_generate_random_block(k, 3 * sizeof(des_cblock));
des_set_odd_parity(&k[0]);
des_set_odd_parity(&k[1]);
des_set_odd_parity(&k[2]);
} while(des_is_weak_key(&k[0]) ||
des_is_weak_key(&k[1]) ||
des_is_weak_key(&k[2]));
}
static void
DES3_schedule(krb5_context context,
struct key_data *key)
{
des_cblock *k = key->key->keyvalue.data;
des_key_schedule *s = key->schedule->data;
des_set_key(&k[0], s[0]);
des_set_key(&k[1], s[1]);
des_set_key(&k[2], s[2]);
}
/*
* A = A xor B. A & B are 8 bytes.
*/
static void
xor (des_cblock *key, const unsigned char *b)
{
unsigned char *a = (unsigned char*)key;
a[0] ^= b[0];
a[1] ^= b[1];
a[2] ^= b[2];
a[3] ^= b[3];
a[4] ^= b[4];
a[5] ^= b[5];
a[6] ^= b[6];
a[7] ^= b[7];
}
static krb5_error_code
DES3_string_to_key(krb5_context context,
krb5_enctype enctype,
krb5_data password,
krb5_salt salt,
krb5_keyblock *key)
{
char *str;
size_t len;
unsigned char tmp[24];
des_cblock keys[3];
len = password.length + salt.saltvalue.length;
str = malloc(len);
if(str == NULL)
return ENOMEM;
memcpy(str, password.data, password.length);
memcpy(str + password.length, salt.saltvalue.data, salt.saltvalue.length);
{
des_cblock ivec;
des_key_schedule s[3];
int i;
n_fold(str, len, tmp, 24);
for(i = 0; i < 3; i++){
memcpy(keys + i, tmp + i * 8, sizeof(keys[i]));
des_set_odd_parity(keys + i);
if(des_is_weak_key(keys + i))
xor(keys + i, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
des_set_key(keys + i, s[i]);
}
memset(&ivec, 0, sizeof(ivec));
des_ede3_cbc_encrypt((void*)tmp, (void*)tmp, sizeof(tmp),
s[0], s[1], s[2], &ivec, DES_ENCRYPT);
memset(s, 0, sizeof(s));
memset(&ivec, 0, sizeof(ivec));
for(i = 0; i < 3; i++){
memcpy(keys + i, tmp + i * 8, sizeof(keys[i]));
des_set_odd_parity(keys + i);
if(des_is_weak_key(keys + i))
xor(keys + i, (unsigned char*)"\0\0\0\0\0\0\0\xf0");
}
memset(tmp, 0, sizeof(tmp));
}
key->keytype = enctype;
krb5_data_copy(&key->keyvalue, keys, sizeof(keys));
memset(keys, 0, sizeof(keys));
memset(str, 0, len);
free(str);
return 0;
}
static krb5_error_code
DES3_string_to_key_derived(krb5_context context,
krb5_enctype enctype,
krb5_data password,
krb5_salt salt,
krb5_keyblock *key)
{
krb5_error_code ret;
size_t len = password.length + salt.saltvalue.length;
char *s = malloc(len);
if(s == NULL)
return ENOMEM;
memcpy(s, password.data, password.length);
memcpy(s + password.length, salt.saltvalue.data, salt.saltvalue.length);
ret = krb5_string_to_key_derived(context,
s,
len,
enctype,
key);
memset(s, 0, len);
free(s);
return ret;
}
extern struct salt_type des_salt[],
des3_salt[], des3_salt_derived[];
struct key_type keytype_null = {
KEYTYPE_NULL,
"null",
0,
0,
0,
NULL,
NULL,
NULL
};
struct key_type keytype_des = {
KEYTYPE_DES,
"des",
56,
sizeof(des_cblock),
sizeof(des_key_schedule),
DES_random_key,
DES_schedule,
des_salt
};
struct key_type keytype_des3 = {
KEYTYPE_DES3,
"des3",
168,
3 * sizeof(des_cblock),
3 * sizeof(des_key_schedule),
DES3_random_key,
DES3_schedule,
des3_salt
};
struct key_type keytype_des3_derived = {
KEYTYPE_DES3,
"des3",
168,
3 * sizeof(des_cblock),
3 * sizeof(des_key_schedule),
DES3_random_key,
DES3_schedule,
des3_salt_derived
};
struct key_type *keytypes[] = {
&keytype_null,
&keytype_des,
&keytype_des3_derived,
&keytype_des3
};
static int num_keytypes = sizeof(keytypes) / sizeof(keytypes[0]);
static struct key_type *
_find_keytype(krb5_keytype type)
{
int i;
for(i = 0; i < num_keytypes; i++)
if(keytypes[i]->type == type)
return keytypes[i];
return NULL;
}
struct salt_type des_salt[] = {
{
KRB5_PW_SALT,
"pw-salt",
DES_string_to_key
},
{
KRB5_AFS3_SALT,
"afs3-salt",
DES_AFS3_string_to_key
},
{ 0 }
};
struct salt_type des3_salt[] = {
{
KRB5_PW_SALT,
"pw-salt",
DES3_string_to_key
},
{ 0 }
};
struct salt_type des3_salt_derived[] = {
{
KRB5_PW_SALT,
"pw-salt",
DES3_string_to_key_derived
},
{ 0 }
};
krb5_error_code
krb5_salttype_to_string (krb5_context context,
krb5_enctype etype,
krb5_salttype stype,
char **string)
{
struct encryption_type *e;
struct salt_type *st;
e = _find_enctype (etype);
if (e == NULL)
return KRB5_PROG_ETYPE_NOSUPP;
for (st = e->keytype->string_to_key; st && st->type; st++) {
if (st->type == stype) {
*string = strdup (st->name);
if (*string == NULL)
return ENOMEM;
return 0;
}
}
return HEIM_ERR_SALTTYPE_NOSUPP;
}
krb5_error_code
krb5_get_pw_salt(krb5_context context,
krb5_const_principal principal,
krb5_salt *salt)
{
size_t len;
int i;
krb5_error_code ret;
char *p;
salt->salttype = KRB5_PW_SALT;
len = strlen(principal->realm);
for (i = 0; i < principal->name.name_string.len; ++i)
len += strlen(principal->name.name_string.val[i]);
ret = krb5_data_alloc (&salt->saltvalue, len);
if (ret)
return ret;
p = salt->saltvalue.data;
memcpy (p, principal->realm, strlen(principal->realm));
p += strlen(principal->realm);
for (i = 0; i < principal->name.name_string.len; ++i) {
memcpy (p,
principal->name.name_string.val[i],
strlen(principal->name.name_string.val[i]));
p += strlen(principal->name.name_string.val[i]);
}
return 0;
}
krb5_error_code
krb5_free_salt(krb5_context context,
krb5_salt salt)
{
krb5_data_free(&salt.saltvalue);
return 0;
}
krb5_error_code
krb5_string_to_key_data (krb5_context context,
krb5_enctype enctype,
krb5_data password,
krb5_principal principal,
krb5_keyblock *key)
{
krb5_error_code ret;
krb5_salt salt;
ret = krb5_get_pw_salt(context, principal, &salt);
if(ret)
return ret;
ret = krb5_string_to_key_data_salt(context, enctype, password, salt, key);
krb5_free_salt(context, salt);
return ret;
}
krb5_error_code
krb5_string_to_key (krb5_context context,
krb5_enctype enctype,
const char *password,
krb5_principal principal,
krb5_keyblock *key)
{
krb5_data pw;
pw.data = (void*)password;
pw.length = strlen(password);
return krb5_string_to_key_data(context, enctype, pw, principal, key);
}
krb5_error_code
krb5_string_to_key_data_salt (krb5_context context,
krb5_enctype enctype,
krb5_data password,
krb5_salt salt,
krb5_keyblock *key)
{
struct encryption_type *et =_find_enctype(enctype);
struct salt_type *st;
if(et == NULL)
return KRB5_PROG_ETYPE_NOSUPP;
for(st = et->keytype->string_to_key; st && st->type; st++)
if(st->type == salt.salttype)
return (*st->string_to_key)(context, enctype, password, salt, key);
return HEIM_ERR_SALTTYPE_NOSUPP;
}
krb5_error_code
krb5_string_to_key_salt (krb5_context context,
krb5_enctype enctype,
const char *password,
krb5_salt salt,
krb5_keyblock *key)
{
krb5_data pw;
pw.data = (void*)password;
pw.length = strlen(password);
return krb5_string_to_key_data_salt(context, enctype, pw, salt, key);
}
krb5_error_code
krb5_keytype_to_string(krb5_context context,
krb5_keytype keytype,
char **string)
{
struct key_type *kt = _find_keytype(keytype);
if(kt == NULL)
return KRB5_PROG_KEYTYPE_NOSUPP;
*string = strdup(kt->name);
if(*string == NULL)
return ENOMEM;
return 0;
}
krb5_error_code
krb5_string_to_keytype(krb5_context context,
const char *string,
krb5_keytype *keytype)
{
int i;
for(i = 0; i < num_keytypes; i++)
if(strcasecmp(keytypes[i]->name, string) == 0){
*keytype = keytypes[i]->type;
return 0;
}
return KRB5_PROG_KEYTYPE_NOSUPP;
}
krb5_error_code
krb5_generate_random_keyblock(krb5_context context,
krb5_enctype type,
krb5_keyblock *key)
{
krb5_error_code ret;
struct encryption_type *et = _find_enctype(type);
if(et == NULL)
return KRB5_PROG_ETYPE_NOSUPP;
ret = krb5_data_alloc(&key->keyvalue, et->keytype->size);
if(ret)
return ret;
key->keytype = type;
if(et->keytype->random_key)
(*et->keytype->random_key)(context, key);
else
krb5_generate_random_block(key->keyvalue.data,
key->keyvalue.length);
return 0;
}
static krb5_error_code
_key_schedule(krb5_context context,
struct key_data *key)
{
krb5_error_code ret;
struct encryption_type *et = _find_enctype(key->key->keytype);
struct key_type *kt = et->keytype;
if(kt->schedule == NULL)
return 0;
ALLOC(key->schedule, 1);
if(key->schedule == NULL)
return ENOMEM;
ret = krb5_data_alloc(key->schedule, kt->schedule_size);
if(ret) {
free(key->schedule);
key->schedule = NULL;
return ret;
}
(*kt->schedule)(context, key);
return 0;
}
/************************************************************
* *
************************************************************/
static void
NONE_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
}
static void
CRC32_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
u_int32_t crc;
unsigned char *r = C->checksum.data;
crc_init_table ();
crc = crc_update (data, len, 0);
r[0] = crc & 0xff;
r[1] = (crc >> 8) & 0xff;
r[2] = (crc >> 16) & 0xff;
r[3] = (crc >> 24) & 0xff;
}
static void
RSA_MD4_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md4 m;
md4_init(&m);
md4_update(&m, data, len);
md4_finito(&m, C->checksum.data);
}
static void
RSA_MD4_DES_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *cksum)
{
struct md4 md4;
des_cblock ivec;
unsigned char *p = cksum->checksum.data;
krb5_generate_random_block(p, 8);
md4_init(&md4);
md4_update(&md4, p, 8);
md4_update(&md4, data, len);
md4_finito(&md4, p + 8);
memset (&ivec, 0, sizeof(ivec));
des_cbc_encrypt((des_cblock*)p,
(des_cblock*)p,
24,
key->schedule->data,
&ivec,
DES_ENCRYPT);
}
static krb5_error_code
RSA_MD4_DES_verify(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md4 md4;
unsigned char tmp[24];
unsigned char res[16];
des_cblock ivec;
krb5_error_code ret = 0;
memset(&ivec, 0, sizeof(ivec));
des_cbc_encrypt(C->checksum.data,
(void*)tmp,
C->checksum.length,
key->schedule->data,
&ivec,
DES_DECRYPT);
md4_init(&md4);
md4_update(&md4, tmp, 8); /* confounder */
md4_update(&md4, data, len);
md4_finito(&md4, res);
if(memcmp(res, tmp + 8, sizeof(res)) != 0)
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
memset(tmp, 0, sizeof(tmp));
memset(res, 0, sizeof(res));
return ret;
}
static void
RSA_MD5_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md5 m;
md5_init(&m);
md5_update(&m, data, len);
md5_finito(&m, C->checksum.data);
}
static void
RSA_MD5_DES_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md5 md5;
des_cblock ivec;
unsigned char *p = C->checksum.data;
krb5_generate_random_block(p, 8);
md5_init(&md5);
md5_update(&md5, p, 8);
md5_update(&md5, data, len);
md5_finito(&md5, p + 8);
memset (&ivec, 0, sizeof(ivec));
des_cbc_encrypt((des_cblock*)p,
(des_cblock*)p,
24,
key->schedule->data,
&ivec,
DES_ENCRYPT);
}
static krb5_error_code
RSA_MD5_DES_verify(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md5 md5;
unsigned char tmp[24];
unsigned char res[16];
des_cblock ivec;
des_key_schedule *sched = key->schedule->data;
krb5_error_code ret = 0;
memset(&ivec, 0, sizeof(ivec));
des_cbc_encrypt(C->checksum.data,
(void*)tmp,
C->checksum.length,
sched[0],
&ivec,
DES_DECRYPT);
md5_init(&md5);
md5_update(&md5, tmp, 8); /* confounder */
md5_update(&md5, data, len);
md5_finito(&md5, res);
if(memcmp(res, tmp + 8, sizeof(res)) != 0)
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
memset(tmp, 0, sizeof(tmp));
memset(res, 0, sizeof(res));
return ret;
}
static void
RSA_MD5_DES3_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md5 md5;
des_cblock ivec;
unsigned char *p = C->checksum.data;
des_key_schedule *sched = key->schedule->data;
krb5_generate_random_block(p, 8);
md5_init(&md5);
md5_update(&md5, p, 8);
md5_update(&md5, data, len);
md5_finito(&md5, p + 8);
memset (&ivec, 0, sizeof(ivec));
des_ede3_cbc_encrypt((des_cblock*)p,
(des_cblock*)p,
24,
sched[0], sched[1], sched[2],
&ivec,
DES_ENCRYPT);
}
static krb5_error_code
RSA_MD5_DES3_verify(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct md5 md5;
unsigned char tmp[24];
unsigned char res[16];
des_cblock ivec;
des_key_schedule *sched = key->schedule->data;
krb5_error_code ret = 0;
memset(&ivec, 0, sizeof(ivec));
des_ede3_cbc_encrypt(C->checksum.data,
(void*)tmp,
C->checksum.length,
sched[0], sched[1], sched[2],
&ivec,
DES_DECRYPT);
md5_init(&md5);
md5_update(&md5, tmp, 8); /* confounder */
md5_update(&md5, data, len);
md5_finito(&md5, res);
if(memcmp(res, tmp + 8, sizeof(res)) != 0)
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
memset(tmp, 0, sizeof(tmp));
memset(res, 0, sizeof(res));
return ret;
}
static void
SHA1_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *C)
{
struct sha m;
sha_init(&m);
sha_update(&m, data, len);
sha_finito(&m, C->checksum.data);
}
/* HMAC according to RFC2104 */
static void
hmac(krb5_context context,
struct checksum_type *cm,
void *data,
size_t len,
struct key_data *keyblock,
Checksum *result)
{
unsigned char *ipad, *opad;
unsigned char *key;
size_t key_len;
int i;
if(keyblock->key->keyvalue.length > cm->blocksize){
(*cm->checksum)(context,
keyblock,
keyblock->key->keyvalue.data,
keyblock->key->keyvalue.length,
result);
key = result->checksum.data;
key_len = result->checksum.length;
} else {
key = keyblock->key->keyvalue.data;
key_len = keyblock->key->keyvalue.length;
}
ipad = malloc(cm->blocksize + len);
opad = malloc(cm->blocksize + cm->checksumsize);
memset(ipad, 0x36, cm->blocksize);
memset(opad, 0x5c, cm->blocksize);
for(i = 0; i < key_len; i++){
ipad[i] ^= key[i];
opad[i] ^= key[i];
}
memcpy(ipad + cm->blocksize, data, len);
(*cm->checksum)(context, keyblock, ipad, cm->blocksize + len, result);
memcpy(opad + cm->blocksize, result->checksum.data,
result->checksum.length);
(*cm->checksum)(context, keyblock, opad,
cm->blocksize + cm->checksumsize, result);
memset(ipad, 0, cm->blocksize + len);
free(ipad);
memset(opad, 0, cm->blocksize + cm->checksumsize);
free(opad);
}
static void
HMAC_SHA1_DES3_checksum(krb5_context context,
struct key_data *key,
void *data,
size_t len,
Checksum *result)
{
struct checksum_type *c = _find_checksum(CKSUMTYPE_SHA1);
/* iovec? */
unsigned char *p = malloc(4 + len);
k_put_int(p, len, 4);
memcpy(p + 4, data , len);
hmac(context, c, p, 4 + len, key, result);
memset(p, 0, 4 + len);
free(p);
}
struct checksum_type checksum_none = {
CKSUMTYPE_NONE,
"none",
1,
0,
0,
NONE_checksum,
NULL
};
struct checksum_type checksum_crc32 = {
CKSUMTYPE_CRC32,
"crc32",
1,
4,
0,
CRC32_checksum,
NULL
};
struct checksum_type checksum_rsa_md4 = {
CKSUMTYPE_RSA_MD4,
"rsa-md4",
64,
16,
F_CPROOF,
RSA_MD4_checksum,
NULL
};
struct checksum_type checksum_rsa_md4_des = {
CKSUMTYPE_RSA_MD4_DES,
"rsa-md4-des",
64,
24,
F_KEYED | F_CPROOF | F_VARIANT,
RSA_MD4_DES_checksum,
RSA_MD4_DES_verify
};
#if 0
struct checksum_type checksum_des_mac = {
CKSUMTYPE_DES_MAC,
"des-mac",
0,
0,
0,
DES_MAC_checksum,
};
struct checksum_type checksum_des_mac_k = {
CKSUMTYPE_DES_MAC_K,
"des-mac-k",
0,
0,
0,
DES_MAC_K_checksum,
};
struct checksum_type checksum_rsa_md4_des_k = {
CKSUMTYPE_RSA_MD4_DES_K,
"rsa-md4-des-k",
0,
0,
0,
RSA_MD4_DES_K_checksum,
RSA_MD4_DES_K_verify,
};
#endif
struct checksum_type checksum_rsa_md5 = {
CKSUMTYPE_RSA_MD5,
"rsa-md5",
64,
16,
F_CPROOF,
RSA_MD5_checksum,
NULL
};
struct checksum_type checksum_rsa_md5_des = {
CKSUMTYPE_RSA_MD5_DES,
"rsa-md5-des",
64,
24,
F_KEYED | F_CPROOF | F_VARIANT,
RSA_MD5_DES_checksum,
RSA_MD5_DES_verify,
};
struct checksum_type checksum_rsa_md5_des3 = {
CKSUMTYPE_RSA_MD5_DES3,
"rsa-md5-des3",
64,
24,
F_KEYED | F_CPROOF | F_VARIANT,
RSA_MD5_DES3_checksum,
RSA_MD5_DES3_verify,
};
struct checksum_type checksum_sha1 = {
CKSUMTYPE_SHA1,
"sha1",
80,
20,
F_CPROOF,
SHA1_checksum,
NULL
};
struct checksum_type checksum_hmac_sha1_des3 = {
CKSUMTYPE_HMAC_SHA1_DES3,
"hmac-sha1-des3",
80,
20,
F_KEYED | F_CPROOF | F_DERIVED,
HMAC_SHA1_DES3_checksum,
NULL
};
struct checksum_type *checksum_types[] = {
&checksum_none,
&checksum_crc32,
&checksum_rsa_md4,
&checksum_rsa_md4_des,
#if 0
&checksum_des_mac,
&checksum_des_mac_k,
&checksum_rsa_md4_des_k,
#endif
&checksum_rsa_md5,
&checksum_rsa_md5_des,
&checksum_rsa_md5_des3,
&checksum_sha1,
&checksum_hmac_sha1_des3
};
static int num_checksums = sizeof(checksum_types) / sizeof(checksum_types[0]);
static struct checksum_type *
_find_checksum(krb5_cksumtype type)
{
int i;
for(i = 0; i < num_checksums; i++)
if(checksum_types[i]->type == type)
return checksum_types[i];
return NULL;
}
static krb5_error_code
get_checksum_key(krb5_context context,
krb5_crypto crypto,
unsigned usage, /* not krb5_key_usage */
struct checksum_type *ct,
struct key_data **key)
{
krb5_error_code ret = 0;
if(ct->flags & F_DERIVED)
ret = _get_derived_key(context, crypto, usage, key);
else {
if(ct->flags & F_VARIANT) {
int i;
*key = _new_derived_key(crypto, 0xff/* KRB5_KU_RFC1510_VARIANT */);
if(*key == NULL)
return ENOMEM;
ret = krb5_copy_keyblock(context, crypto->key.key, &(*key)->key);
if(ret)
return ret;
for(i = 0; i < (*key)->key->keyvalue.length; i++)
((unsigned char*)(*key)->key->keyvalue.data)[i] ^= 0xF0;
} else
*key = &crypto->key;
}
if(ret == 0)
ret = _key_schedule(context, *key);
return ret;
}
static krb5_error_code
create_checksum(krb5_context context,
krb5_crypto crypto,
unsigned usage, /* not krb5_key_usage */
krb5_cksumtype type, /* if crypto == NULL */
void *data,
size_t len,
Checksum *result)
{
krb5_error_code ret;
struct checksum_type *ct;
struct key_data *dkey;
int keyed_checksum;
if(crypto) {
ct = crypto->et->keyed_checksum;
if(ct == NULL)
ct = crypto->et->cksumtype;
} else
ct = _find_checksum(type);
if(ct == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
keyed_checksum = (ct->flags & F_KEYED) != 0;
if(keyed_checksum && crypto == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP; /* XXX */
if(keyed_checksum)
ret = get_checksum_key(context, crypto, usage, ct, &dkey);
else
dkey = NULL;
result->cksumtype = ct->type;
krb5_data_alloc(&result->checksum, ct->checksumsize);
(*ct->checksum)(context, dkey, data, len, result);
return 0;
}
krb5_error_code
krb5_create_checksum(krb5_context context,
krb5_crypto crypto,
unsigned usage_or_type,
void *data,
size_t len,
Checksum *result)
{
return create_checksum(context, crypto,
CHECKSUM_USAGE(usage_or_type),
usage_or_type, data, len, result);
}
static krb5_error_code
verify_checksum(krb5_context context,
krb5_crypto crypto,
unsigned usage, /* not krb5_key_usage */
void *data,
size_t len,
Checksum *cksum)
{
krb5_error_code ret;
struct key_data *dkey;
int keyed_checksum;
Checksum c;
struct checksum_type *ct;
if(crypto) {
ct = crypto->et->keyed_checksum;
if(ct == NULL)
ct = crypto->et->cksumtype;
} else
ct = _find_checksum(cksum->cksumtype);
if(ct == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
if(ct->checksumsize != cksum->checksum.length)
return KRB5KRB_AP_ERR_BAD_INTEGRITY; /* XXX */
keyed_checksum = (ct->flags & F_KEYED) != 0;
if(keyed_checksum && crypto == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP; /* XXX */
if(keyed_checksum)
ret = get_checksum_key(context, crypto, usage, ct, &dkey);
else
dkey = NULL;
if(ct->verify)
return (*ct->verify)(context, dkey, data, len, cksum);
ret = create_checksum(context, crypto, usage, ct->type, data, len, &c);
if(ret)
return ret;
if(c.checksum.length != cksum->checksum.length ||
memcmp(c.checksum.data, cksum->checksum.data, c.checksum.length))
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
else
ret = 0;
free_Checksum(&c);
return ret;
}
krb5_error_code
krb5_verify_checksum(krb5_context context,
krb5_crypto crypto,
krb5_key_usage usage,
void *data,
size_t len,
Checksum *cksum)
{
return verify_checksum(context, crypto,
CHECKSUM_USAGE(usage), data, len, cksum);
}
krb5_error_code
krb5_checksumsize(krb5_context context,
krb5_cksumtype type,
size_t *size)
{
struct checksum_type *ct = _find_checksum(type);
if(ct == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
*size = ct->checksumsize;
return 0;
}
krb5_boolean
krb5_checksum_is_keyed(krb5_context context,
krb5_cksumtype type)
{
struct checksum_type *ct = _find_checksum(type);
if(ct == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
return ct->flags & F_KEYED;
}
krb5_boolean
krb5_checksum_is_collision_proof(krb5_context context,
krb5_cksumtype type)
{
struct checksum_type *ct = _find_checksum(type);
if(ct == NULL)
return KRB5_PROG_SUMTYPE_NOSUPP;
return ct->flags & F_CPROOF;
}
/************************************************************
* *
************************************************************/
static void
NULL_encrypt(struct key_data *key,
void *data,
size_t len,
krb5_boolean encrypt)
{
}
static void
DES_CBC_encrypt_null_ivec(struct key_data *key,
void *data,
size_t len,
krb5_boolean encrypt)
{
des_cblock ivec;
des_key_schedule *s = key->schedule->data;
memset(&ivec, 0, sizeof(ivec));
des_cbc_encrypt(data, data, len, *s, &ivec, encrypt);
}
static void
DES_CBC_encrypt_key_ivec(struct key_data *key,
void *data,
size_t len,
krb5_boolean encrypt)
{
des_cblock ivec;
des_key_schedule *s = key->schedule->data;
memcpy(&ivec, key->key->keyvalue.data, sizeof(ivec));
des_cbc_encrypt(data, data, len, *s, &ivec, encrypt);
}
static void
DES3_CBC_encrypt(struct key_data *key,
void *data,
size_t len,
krb5_boolean encrypt)
{
des_cblock ivec;
des_key_schedule *s = key->schedule->data;
memset(&ivec, 0, sizeof(ivec));
des_ede3_cbc_encrypt(data, data, len, s[0], s[1], s[2], &ivec, encrypt);
}
static struct encryption_type etypes[] = {
{
ETYPE_NULL,
"null",
1,
0,
&keytype_null,
&checksum_none,
NULL,
0,
NULL_encrypt,
},
{
ETYPE_DES_CBC_CRC,
"des-cbc-crc",
8,
8,
&keytype_des,
&checksum_crc32,
NULL,
0,
DES_CBC_encrypt_key_ivec,
},
{
ETYPE_DES_CBC_MD4,
"des-cbc-md4",
8,
8,
&keytype_des,
&checksum_rsa_md4,
&checksum_rsa_md4_des,
0,
DES_CBC_encrypt_null_ivec,
},
{
ETYPE_DES_CBC_MD5,
"des-cbc-md5",
8,
8,
&keytype_des,
&checksum_rsa_md5,
&checksum_rsa_md5_des,
0,
DES_CBC_encrypt_null_ivec,
},
{
ETYPE_DES3_CBC_MD5,
"des3-cbc-md5",
8,
8,
&keytype_des3,
&checksum_rsa_md5,
&checksum_rsa_md5_des3,
0,
DES3_CBC_encrypt,
},
#if NEW_DES3_CODE
{
ETYPE_DES3_CBC_SHA1,
"des3-cbc-sha1",
8,
8,
&keytype_des3_derived,
&checksum_sha1,
&checksum_hmac_sha1_des3,
F_DERIVED,
DES3_CBC_encrypt,
},
#else
{
ETYPE_NEW_DES3_CBC_SHA1,
"new-des3-cbc-sha1",
8,
8,
&keytype_des3_derived,
&checksum_sha1,
&checksum_hmac_sha1_des3,
F_DERIVED,
DES3_CBC_encrypt,
},
{
ETYPE_DES3_CBC_SHA1,
"des3-cbc-sha1",
8,
8,
&keytype_des3,
&checksum_sha1,
&checksum_hmac_sha1_des3,
0,
DES3_CBC_encrypt,
},
#endif
{
ETYPE_DES_CBC_NONE,
"des-cbc-none",
8,
0,
&keytype_des,
&checksum_none,
NULL,
0,
DES_CBC_encrypt_null_ivec,
},
{
ETYPE_DES3_CBC_NONE,
"des3-cbc-none",
8,
0,
&keytype_des3_derived,
&checksum_none,
NULL,
0,
DES_CBC_encrypt_null_ivec,
},
};
static unsigned num_etypes = sizeof(etypes) / sizeof(etypes[0]);
static struct encryption_type *
_find_enctype(krb5_enctype type)
{
int i;
for(i = 0; i < num_etypes; i++)
if(etypes[i].type == type)
return &etypes[i];
return NULL;
}
krb5_error_code
krb5_enctype_to_string(krb5_context context,
krb5_enctype etype,
char **string)
{
struct encryption_type *e;
e = _find_enctype(etype);
if(e == NULL)
return KRB5_PROG_ETYPE_NOSUPP;
*string = strdup(e->name);
if(*string == NULL)
return ENOMEM;
return 0;
}
krb5_error_code
krb5_string_to_enctype(krb5_context context,
const char *string,
krb5_enctype *etype)
{
int i;
for(i = 0; i < num_etypes; i++)
if(strcasecmp(etypes[i].name, string) == 0){
*etype = etypes[i].type;
return 0;
}
return KRB5_PROG_ETYPE_NOSUPP;
}
krb5_error_code
krb5_enctype_to_keytype(krb5_context context,
krb5_enctype etype,
krb5_keytype *keytype)
{
struct encryption_type *e = _find_enctype(etype);
krb5_warnx(context, "krb5_enctype_to_keytype(%u)", etype);
if(e == NULL)
return KRB5_PROG_ETYPE_NOSUPP;
*keytype = e->keytype->type; /* XXX */
return 0;
}
#if 0
krb5_error_code
krb5_keytype_to_enctype(krb5_context context,
krb5_keytype keytype,
krb5_enctype *etype)
{
struct key_type *kt = _find_keytype(keytype);
krb5_warnx(context, "krb5_keytype_to_enctype(%u)", keytype);
if(kt == NULL)
return KRB5_PROG_KEYTYPE_NOSUPP;
*etype = kt->best_etype;
return 0;
}
#endif
krb5_error_code
krb5_enctype_valid(krb5_context context,
krb5_enctype etype)
{
return _find_enctype(etype) != NULL;
}
/* if two enctypes have compatible keys */
krb5_boolean
krb5_enctypes_comptible_keys(krb5_context context,
krb5_enctype etype1,
krb5_enctype etype2)
{
struct encryption_type *e1 = _find_enctype(etype1);
struct encryption_type *e2 = _find_enctype(etype2);
return e1 != NULL && e2 != NULL && e1->keytype == e2->keytype;
}
static krb5_boolean
derived_crypto(krb5_context context,
krb5_crypto crypto)
{
return (crypto->et->flags & F_DERIVED) != 0;
}
#define CHECKSUMSIZE(C) ((C)->checksumsize)
#define CHECKSUMTYPE(C) ((C)->type)
static krb5_error_code
encrypt_internal_derived(krb5_context context,
krb5_crypto crypto,
unsigned usage,
void *data,
size_t len,
krb5_data *result)
{
size_t sz, block_sz, checksum_sz;
Checksum cksum;
unsigned char *p, *q;
krb5_error_code ret;
struct key_data *dkey;
struct encryption_type *et = crypto->et;
checksum_sz = CHECKSUMSIZE(et->keyed_checksum);
sz = et->confoundersize + 4 /* length */ + len;
block_sz = (sz + et->blocksize - 1) &~ (et->blocksize - 1); /* pad */
p = calloc(1, block_sz + checksum_sz);
if(p == NULL)
return ENOMEM;
q = p;
krb5_generate_random_block(q, et->confoundersize); /* XXX */
q += et->confoundersize;
k_put_int(q, len, 4);
q += 4;
memcpy(q, data, len);
ret = create_checksum(context,
crypto,
INTEGRITY_USAGE(usage),
0,
p,
block_sz,
&cksum);
if(ret == 0 && cksum.checksum.length != checksum_sz)
ret = KRB5_CRYPTO_INTERNAL;
if(ret) {
memset(p, 0, block_sz + checksum_sz);
free(p);
return ret;
}
memcpy(p + block_sz, cksum.checksum.data, cksum.checksum.length);
ret = _get_derived_key(context, crypto, ENCRYPTION_USAGE(usage), &dkey);
if(ret) {
memset(p, 0, block_sz + checksum_sz);
free(p);
return ret;
}
ret = _key_schedule(context, dkey);
if(ret) {
memset(p, 0, block_sz);
free(p);
return ret;
}
#ifdef CRYPTO_DEBUG
krb5_crypto_debug(context, 1, block_sz, dkey->key);
#endif
(*et->encrypt)(dkey, p, block_sz, 1);
result->data = p;
result->length = block_sz + checksum_sz;
return 0;
}
static krb5_error_code
encrypt_internal(krb5_context context,
krb5_crypto crypto,
void *data,
size_t len,
krb5_data *result)
{
size_t sz, block_sz, checksum_sz;
Checksum cksum;
unsigned char *p, *q;
krb5_error_code ret;
struct encryption_type *et = crypto->et;
checksum_sz = CHECKSUMSIZE(et->cksumtype);
sz = et->confoundersize + checksum_sz + len;
block_sz = (sz + et->blocksize - 1) &~ (et->blocksize - 1); /* pad */
p = calloc(1, block_sz);
if(p == NULL)
return ENOMEM;
q = p;
krb5_generate_random_block(q, et->confoundersize); /* XXX */
q += et->confoundersize;
memset(q, 0, checksum_sz);
q += checksum_sz;
memcpy(q, data, len);
ret = create_checksum(context,
NULL,
0,
CHECKSUMTYPE(et->cksumtype),
p,
block_sz,
&cksum);
if(ret == 0 && cksum.checksum.length != checksum_sz)
ret = KRB5_CRYPTO_INTERNAL;
if(ret) {
memset(p, 0, block_sz);
free(p);
return ret;
}
memcpy(p + et->confoundersize, cksum.checksum.data, cksum.checksum.length);
ret = _key_schedule(context, &crypto->key);
if(ret) {
memset(p, 0, block_sz);
free(p);
return ret;
}
#ifdef CRYPTO_DEBUG
krb5_crypto_debug(context, 1, block_sz, crypto->key.key);
#endif
(*et->encrypt)(&crypto->key, p, block_sz, 1);
result->data = p;
result->length = block_sz;
return 0;
}
static krb5_error_code
decrypt_internal_derived(krb5_context context,
krb5_crypto crypto,
unsigned usage,
void *data,
size_t len,
krb5_data *result)
{
size_t checksum_sz;
Checksum cksum;
unsigned char *p;
krb5_error_code ret;
struct key_data *dkey;
struct encryption_type *et = crypto->et;
unsigned long l;
p = malloc(len);
if(p == NULL)
return ENOMEM;
memcpy(p, data, len);
checksum_sz = CHECKSUMSIZE(et->keyed_checksum);
len -= checksum_sz;
ret = _get_derived_key(context, crypto, ENCRYPTION_USAGE(usage), &dkey);
if(ret) {
free(p);
return ret;
}
ret = _key_schedule(context, dkey);
if(ret) {
free(p);
return ret;
}
#ifdef CRYPTO_DEBUG
krb5_crypto_debug(context, 0, len, dkey->key);
#endif
(*et->encrypt)(dkey, p, len, 0);
cksum.checksum.data = p + len;
cksum.checksum.length = checksum_sz;
ret = verify_checksum(context,
crypto,
INTEGRITY_USAGE(usage),
p,
len,
&cksum);
if(ret) {
free(p);
return ret;
}
k_get_int(p + et->confoundersize, &l, 4);
memmove(p, p + et->confoundersize + 4, l);
result->data = realloc(p, l);
if(p == NULL) {
free(p);
return ENOMEM;
}
result->length = l;
return 0;
}
static krb5_error_code
decrypt_internal(krb5_context context,
krb5_crypto crypto,
void *data,
size_t len,
krb5_data *result)
{
krb5_error_code ret;
unsigned char *p;
Checksum cksum;
size_t checksum_sz, l;
struct encryption_type *et = crypto->et;
checksum_sz = CHECKSUMSIZE(et->cksumtype);
p = malloc(len);
if(p == NULL)
return ENOMEM;
memcpy(p, data, len);
ret = _key_schedule(context, &crypto->key);
if(ret) {
free(p);
return ret;
}
#ifdef CRYPTO_DEBUG
krb5_crypto_debug(context, 0, len, crypto->key.key);
#endif
(*et->encrypt)(&crypto->key, p, len, 0);
ret = krb5_data_copy(&cksum.checksum, p + et->confoundersize, checksum_sz);
if(ret) {
free(p);
return ret;
}
memset(p + et->confoundersize, 0, checksum_sz);
cksum.cksumtype = CHECKSUMTYPE(et->cksumtype);
ret = verify_checksum(context, NULL, 0, p, len, &cksum);
free_Checksum(&cksum);
if(ret) {
free(p);
return ret;
}
l = len - et->confoundersize - checksum_sz;
memmove(p, p + et->confoundersize + checksum_sz, l);
result->data = realloc(p, l);
if(result->data == NULL) {
free(p);
return ENOMEM;
}
result->length = l;
return 0;
}
krb5_error_code
krb5_encrypt(krb5_context context,
krb5_crypto crypto,
unsigned usage,
void *data,
size_t len,
krb5_data *result)
{
if(derived_crypto(context, crypto))
return encrypt_internal_derived(context, crypto, usage,
data, len, result);
else
return encrypt_internal(context, crypto, data, len, result);
}
krb5_error_code
krb5_encrypt_EncryptedData(krb5_context context,
krb5_crypto crypto,
unsigned usage,
void *data,
size_t len,
int kvno,
EncryptedData *result)
{
result->etype = CRYPTO_ETYPE(crypto);
if(kvno){
ALLOC(result->kvno, 1);
*result->kvno = kvno;
}else
result->kvno = NULL;
return krb5_encrypt(context, crypto, usage, data, len, &result->cipher);
}
krb5_error_code
krb5_decrypt(krb5_context context,
krb5_crypto crypto,
unsigned usage,
void *data,
size_t len,
krb5_data *result)
{
if(derived_crypto(context, crypto))
return decrypt_internal_derived(context, crypto, usage,
data, len, result);
else
return decrypt_internal(context, crypto, data, len, result);
}
krb5_error_code
krb5_decrypt_EncryptedData(krb5_context context,
krb5_crypto crypto,
unsigned usage,
EncryptedData *e,
krb5_data *result)
{
return krb5_decrypt(context, crypto, usage,
e->cipher.data, e->cipher.length, result);
}
/************************************************************
* *
************************************************************/
void
krb5_generate_random_block(void *buf, size_t len)
{
des_cblock key, out;
static des_cblock counter;
static des_key_schedule schedule;
int i;
static int initialized = 0;
if(!initialized) {
des_new_random_key(&key);
des_set_key(&key, schedule);
memset(&key, 0, sizeof(key));
des_new_random_key(&counter);
}
while(len > 0) {
des_ecb_encrypt(&counter, &out, schedule, DES_ENCRYPT);
for(i = 7; i >=0; i--)
if(counter[i]++)
break;
memcpy(buf, out, min(len, sizeof(out)));
len -= min(len, sizeof(out));
buf = (char*)buf + sizeof(out);
}
}
/* XXX should be moved someplace else */
static void
DES3_postproc(unsigned char *k, size_t len, struct key_data *key)
{
unsigned char x[24];
int ki = 0, xi = 0, kb = 8, xb = 8;
memset(x, 0, sizeof(x));
/* insert a parity bit after every seven bits (I'm not
convinced that the first 21 bytes has more entropy than the
who 24 byte block...) */
while(xi < 24) {
unsigned u = k[ki] & ((1 << kb) - 1);
if(kb == xb)
x[xi] |= u;
else if(kb > xb)
x[xi] |= u >> (kb - xb);
else /* kb < xb */
x[xi] |= u << (xb - kb);
if(kb < xb - 1) {
xb -= kb;
kb = 8;
ki++;
} else {
kb -= xb - 1;
xb = 8;
xi++;
}
}
k = key->key->keyvalue.data;
memcpy(k, x, 24);
memset(x, 0, sizeof(x));
krb5_data_free(key->schedule);
free(key->schedule);
key->schedule = NULL;
des_set_odd_parity((des_cblock*)k);
des_set_odd_parity((des_cblock*)(k + 8));
des_set_odd_parity((des_cblock*)(k + 16));
}
static krb5_error_code
derive_key(krb5_context context,
struct encryption_type *et,
struct key_data *key,
void *constant,
size_t len)
{
unsigned char *k;
unsigned int nblocks = 0, i;
krb5_error_code ret = 0;
struct key_type *kt = et->keytype;
ret = _key_schedule(context, key);
if(ret)
return ret;
if(et->blocksize * 8 < kt->bits ||
len != et->blocksize) {
nblocks = (kt->bits + et->blocksize * 8 - 1) / (et->blocksize * 8);
k = malloc(nblocks * et->blocksize);
if(k == NULL)
return ENOMEM;
n_fold(constant, len, k, et->blocksize);
for(i = 0; i < nblocks; i++) {
if(i > 0)
memcpy(k + i * et->blocksize,
k + (i - 1) * et->blocksize,
et->blocksize);
(*et->encrypt)(key, k + i * et->blocksize, et->blocksize, 1);
}
} else {
void *c = malloc(len);
if(c == NULL)
return ENOMEM;
memcpy(c, constant, len);
(*et->encrypt)(key, c, len, 1);
k = malloc((kt->bits + 7) / 8);
if(k == NULL)
return ENOMEM;
n_fold(c, len, k, kt->bits);
free(c);
}
/* XXX keytype dependent post-processing */
switch(kt->type) {
case KEYTYPE_DES3:
DES3_postproc(k, nblocks * et->blocksize, key);
break;
default:
krb5_warnx(context, "derive_key() called with unknown keytype (%u)",
kt->type);
ret = KRB5_CRYPTO_INTERNAL;
break;
}
memset(k, 0, nblocks * et->blocksize);
free(k);
return ret;
}
static struct key_data *
_new_derived_key(krb5_crypto crypto, unsigned usage)
{
struct key_usage *d = crypto->key_usage;
d = realloc(d, (crypto->num_key_usage + 1) * sizeof(*d));
if(d == NULL)
return NULL;
crypto->key_usage = d;
d += crypto->num_key_usage++;
memset(d, 0, sizeof(*d));
d->usage = usage;
return &d->key;
}
static krb5_error_code
_get_derived_key(krb5_context context,
krb5_crypto crypto,
unsigned usage,
struct key_data **key)
{
int i;
struct key_data *d;
unsigned char constant[4];
for(i = 0; i < crypto->num_key_usage; i++)
if(crypto->key_usage[i].usage == usage) {
*key = &crypto->key_usage[i].key;
return 0;
}
d = _new_derived_key(crypto, usage);
if(d == NULL)
return ENOMEM;
krb5_copy_keyblock(context, crypto->key.key, &d->key);
k_put_int(constant, usage, 4);
derive_key(context, crypto->et, d, constant, sizeof(constant));
*key = d;
return 0;
}
krb5_error_code
krb5_crypto_init(krb5_context context,
krb5_keyblock *key,
krb5_enctype etype,
krb5_crypto *crypto)
{
krb5_error_code ret;
ALLOC(*crypto, 1);
if(*crypto == NULL)
return ENOMEM;
if(etype == ETYPE_NULL)
etype = key->keytype;
(*crypto)->et = _find_enctype(etype);
if((*crypto)->et == NULL) {
free(*crypto);
return KRB5_PROG_ETYPE_NOSUPP;
}
ret = krb5_copy_keyblock(context, key, &(*crypto)->key.key);
if(ret) {
free(*crypto);
return ret;
}
(*crypto)->key.schedule = NULL;
(*crypto)->num_key_usage = 0;
(*crypto)->key_usage = NULL;
return 0;
}
static void
free_key_data(krb5_context context, struct key_data *key)
{
krb5_free_keyblock(context, key->key);
if(key->schedule) {
memset(key->schedule->data, 0, key->schedule->length);
krb5_free_data(context, key->schedule);
}
}
static void
free_key_usage(krb5_context context, struct key_usage *ku)
{
free_key_data(context, &ku->key);
}
krb5_error_code
krb5_crypto_destroy(krb5_context context,
krb5_crypto crypto)
{
int i;
for(i = 0; i < crypto->num_key_usage; i++)
free_key_usage(context, &crypto->key_usage[i]);
free(crypto->key_usage);
free_key_data(context, &crypto->key);
return 0;
}
krb5_error_code
krb5_string_to_key_derived(krb5_context context,
const void *str,
size_t len,
krb5_enctype etype,
krb5_keyblock *key)
{
struct encryption_type *et = _find_enctype(etype);
krb5_error_code ret;
struct key_data kd;
if(et == NULL)
return KRB5_PROG_ETYPE_NOSUPP;
ALLOC(kd.key, 1);
kd.key->keytype = etype;
krb5_data_alloc(&kd.key->keyvalue, et->keytype->size);
n_fold(str, len, kd.key->keyvalue.data, kd.key->keyvalue.length);
ret = derive_key(context,
et,
&kd,
"kerberos", /* XXX well known constant */
strlen("kerberos"));
ret = krb5_copy_keyblock_contents(context, kd.key, key);
free_key_data(context, &kd);
return ret;
}
#ifdef CRYPTO_DEBUG
static krb5_error_code
krb5_get_keyid(krb5_context context,
krb5_keyblock *key,
u_int32_t *keyid)
{
struct md5 md5;
unsigned char tmp[16];
md5_init(&md5);
md5_update(&md5, key->keyvalue.data, key->keyvalue.length);
md5_finito(&md5, tmp);
*keyid = (tmp[12] << 24) | (tmp[13] << 16) | (tmp[14] << 8) | tmp[15];
return 0;
}
static void
krb5_crypto_debug(krb5_context context,
int encrypt,
size_t len,
krb5_keyblock *key)
{
u_int32_t keyid;
char *kt;
krb5_get_keyid(context, key, &keyid);
krb5_enctype_to_string(context, key->keytype, &kt);
krb5_warnx(context, "%s %lu bytes with key-id %#x (%s)",
encrypt ? "encrypting" : "decrypting",
(unsigned long)len,
keyid,
kt);
free(kt);
}
#endif /* CRYPTO_DEBUG */
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