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/*
* Copyright (c) 1997 - 2004 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. 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 "gsskrb5_locl.h"
#ifdef HEIM_WEAK_CRYPTO
static OM_uint32
unwrap_des
(OM_uint32 * minor_status,
const gsskrb5_ctx context_handle,
const gss_buffer_t input_message_buffer,
gss_buffer_t output_message_buffer,
int * conf_state,
gss_qop_t * qop_state,
krb5_keyblock *key
)
{
u_char *p, *seq;
size_t len;
EVP_MD_CTX *md5;
u_char hash[16];
EVP_CIPHER_CTX des_ctx;
DES_key_schedule schedule;
DES_cblock deskey;
DES_cblock zero;
size_t i;
uint32_t seq_number;
size_t padlength;
OM_uint32 ret;
int cstate;
int cmp;
int token_len;
if (IS_DCE_STYLE(context_handle)) {
token_len = 22 + 8 + 15; /* 45 */
if (input_message_buffer->length < token_len)
return GSS_S_BAD_MECH;
} else {
token_len = input_message_buffer->length;
}
p = input_message_buffer->value;
ret = _gsskrb5_verify_header (&p,
token_len,
"\x02\x01",
GSS_KRB5_MECHANISM);
if (ret)
return ret;
len = (p - (u_char *)input_message_buffer->value)
+ 22 + 8;
if (input_message_buffer->length < len)
return GSS_S_BAD_MECH;
if (memcmp (p, "\x00\x00", 2) != 0)
return GSS_S_BAD_SIG;
p += 2;
if (memcmp (p, "\x00\x00", 2) == 0) {
cstate = 1;
} else if (memcmp (p, "\xFF\xFF", 2) == 0) {
cstate = 0;
} else
return GSS_S_BAD_MIC;
p += 2;
if(conf_state != NULL)
*conf_state = cstate;
if (memcmp (p, "\xff\xff", 2) != 0)
return GSS_S_DEFECTIVE_TOKEN;
p += 2;
p += 16;
len = p - (u_char *)input_message_buffer->value;
if(cstate) {
/* decrypt data */
memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
memset (&zero, 0, sizeof(zero));
for (i = 0; i < sizeof(deskey); ++i)
deskey[i] ^= 0xf0;
EVP_CIPHER_CTX_init(&des_ctx);
EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, deskey, zero, 0);
EVP_Cipher(&des_ctx, p, p, input_message_buffer->length - len);
EVP_CIPHER_CTX_cleanup(&des_ctx);
memset (&schedule, 0, sizeof(schedule));
}
if (IS_DCE_STYLE(context_handle)) {
padlength = 0;
} else {
/* check pad */
ret = _gssapi_verify_pad(input_message_buffer,
input_message_buffer->length - len - 8,
&padlength);
if (ret)
return ret;
}
md5 = EVP_MD_CTX_create();
EVP_DigestInit_ex(md5, EVP_md5(), NULL);
EVP_DigestUpdate(md5, p - 24, 8);
EVP_DigestUpdate(md5, p, input_message_buffer->length - len);
EVP_DigestFinal_ex(md5, hash, NULL);
EVP_MD_CTX_destroy(md5);
memset (&zero, 0, sizeof(zero));
memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
DES_set_key_unchecked (&deskey, &schedule);
DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
&schedule, &zero);
if (ct_memcmp (p - 8, hash, 8) != 0)
return GSS_S_BAD_MIC;
/* verify sequence number */
HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
p -= 16;
EVP_CIPHER_CTX_init(&des_ctx);
EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0);
EVP_Cipher(&des_ctx, p, p, 8);
EVP_CIPHER_CTX_cleanup(&des_ctx);
memset (deskey, 0, sizeof(deskey));
memset (&schedule, 0, sizeof(schedule));
seq = p;
_gsskrb5_decode_om_uint32(seq, &seq_number);
if (context_handle->more_flags & LOCAL)
cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
else
cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
if (cmp != 0) {
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return GSS_S_BAD_MIC;
}
ret = _gssapi_msg_order_check(context_handle->order, seq_number);
if (ret) {
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return ret;
}
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
/* copy out data */
output_message_buffer->length = input_message_buffer->length
- len - padlength - 8;
output_message_buffer->value = malloc(output_message_buffer->length);
if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
return GSS_S_FAILURE;
if (output_message_buffer->value != NULL)
memcpy (output_message_buffer->value,
p + 24,
output_message_buffer->length);
return GSS_S_COMPLETE;
}
#endif
static OM_uint32
unwrap_des3
(OM_uint32 * minor_status,
const gsskrb5_ctx context_handle,
krb5_context context,
const gss_buffer_t input_message_buffer,
gss_buffer_t output_message_buffer,
int * conf_state,
gss_qop_t * qop_state,
krb5_keyblock *key
)
{
u_char *p;
size_t len;
u_char *seq;
krb5_data seq_data;
u_char cksum[20];
uint32_t seq_number;
size_t padlength;
OM_uint32 ret;
int cstate;
krb5_crypto crypto;
Checksum csum;
int cmp;
int token_len;
if (IS_DCE_STYLE(context_handle)) {
token_len = 34 + 8 + 15; /* 57 */
if (input_message_buffer->length < token_len)
return GSS_S_BAD_MECH;
} else {
token_len = input_message_buffer->length;
}
p = input_message_buffer->value;
ret = _gsskrb5_verify_header (&p,
token_len,
"\x02\x01",
GSS_KRB5_MECHANISM);
if (ret)
return ret;
len = (p - (u_char *)input_message_buffer->value)
+ 34 + 8;
if (input_message_buffer->length < len)
return GSS_S_BAD_MECH;
if (ct_memcmp (p, "\x04\x00", 2) != 0) /* HMAC SHA1 DES3_KD */
return GSS_S_BAD_SIG;
p += 2;
if (ct_memcmp (p, "\x02\x00", 2) == 0) {
cstate = 1;
} else if (ct_memcmp (p, "\xff\xff", 2) == 0) {
cstate = 0;
} else
return GSS_S_BAD_MIC;
p += 2;
if(conf_state != NULL)
*conf_state = cstate;
if (ct_memcmp (p, "\xff\xff", 2) != 0)
return GSS_S_DEFECTIVE_TOKEN;
p += 2;
p += 28;
len = p - (u_char *)input_message_buffer->value;
if(cstate) {
/* decrypt data */
krb5_data tmp;
ret = krb5_crypto_init(context, key,
ETYPE_DES3_CBC_NONE, &crypto);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
ret = krb5_decrypt(context, crypto, KRB5_KU_USAGE_SEAL,
p, input_message_buffer->length - len, &tmp);
krb5_crypto_destroy(context, crypto);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
assert (tmp.length == input_message_buffer->length - len);
memcpy (p, tmp.data, tmp.length);
krb5_data_free(&tmp);
}
if (IS_DCE_STYLE(context_handle)) {
padlength = 0;
} else {
/* check pad */
ret = _gssapi_verify_pad(input_message_buffer,
input_message_buffer->length - len - 8,
&padlength);
if (ret)
return ret;
}
/* verify sequence number */
HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
p -= 28;
ret = krb5_crypto_init(context, key,
ETYPE_DES3_CBC_NONE, &crypto);
if (ret) {
*minor_status = ret;
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return GSS_S_FAILURE;
}
{
DES_cblock ivec;
memcpy(&ivec, p + 8, 8);
ret = krb5_decrypt_ivec (context,
crypto,
KRB5_KU_USAGE_SEQ,
p, 8, &seq_data,
&ivec);
}
krb5_crypto_destroy (context, crypto);
if (ret) {
*minor_status = ret;
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return GSS_S_FAILURE;
}
if (seq_data.length != 8) {
krb5_data_free (&seq_data);
*minor_status = 0;
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return GSS_S_BAD_MIC;
}
seq = seq_data.data;
_gsskrb5_decode_om_uint32(seq, &seq_number);
if (context_handle->more_flags & LOCAL)
cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
else
cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
krb5_data_free (&seq_data);
if (cmp != 0) {
*minor_status = 0;
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return GSS_S_BAD_MIC;
}
ret = _gssapi_msg_order_check(context_handle->order, seq_number);
if (ret) {
*minor_status = 0;
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
return ret;
}
HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
/* verify checksum */
memcpy (cksum, p + 8, 20);
memcpy (p + 20, p - 8, 8);
csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
csum.checksum.length = 20;
csum.checksum.data = cksum;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
ret = krb5_verify_checksum (context, crypto,
KRB5_KU_USAGE_SIGN,
p + 20,
input_message_buffer->length - len + 8,
&csum);
krb5_crypto_destroy (context, crypto);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
/* copy out data */
output_message_buffer->length = input_message_buffer->length
- len - padlength - 8;
output_message_buffer->value = malloc(output_message_buffer->length);
if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
return GSS_S_FAILURE;
if (output_message_buffer->value != NULL)
memcpy (output_message_buffer->value,
p + 36,
output_message_buffer->length);
return GSS_S_COMPLETE;
}
OM_uint32 GSSAPI_CALLCONV _gsskrb5_unwrap
(OM_uint32 * minor_status,
gss_const_ctx_id_t context_handle,
const gss_buffer_t input_message_buffer,
gss_buffer_t output_message_buffer,
int * conf_state,
gss_qop_t * qop_state
)
{
krb5_keyblock *key;
krb5_context context;
OM_uint32 ret;
gsskrb5_ctx ctx = (gsskrb5_ctx) context_handle;
output_message_buffer->value = NULL;
output_message_buffer->length = 0;
if (qop_state != NULL)
*qop_state = GSS_C_QOP_DEFAULT;
GSSAPI_KRB5_INIT (&context);
if (ctx->more_flags & IS_CFX)
return _gssapi_unwrap_cfx (minor_status, ctx, context,
input_message_buffer, output_message_buffer,
conf_state, qop_state);
HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
ret = _gsskrb5i_get_token_key(ctx, context, &key);
HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
*minor_status = 0;
switch (key->keytype) {
case KRB5_ENCTYPE_DES_CBC_CRC :
case KRB5_ENCTYPE_DES_CBC_MD4 :
case KRB5_ENCTYPE_DES_CBC_MD5 :
#ifdef HEIM_WEAK_CRYPTO
ret = unwrap_des (minor_status, ctx,
input_message_buffer, output_message_buffer,
conf_state, qop_state, key);
#else
ret = GSS_S_FAILURE;
#endif
break;
case KRB5_ENCTYPE_DES3_CBC_MD5 :
case KRB5_ENCTYPE_DES3_CBC_SHA1 :
ret = unwrap_des3 (minor_status, ctx, context,
input_message_buffer, output_message_buffer,
conf_state, qop_state, key);
break;
case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5:
case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5_56:
ret = _gssapi_unwrap_arcfour (minor_status, ctx, context,
input_message_buffer, output_message_buffer,
conf_state, qop_state, key);
break;
default :
abort();
break;
}
krb5_free_keyblock (context, key);
return ret;
}
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