FreeRDP/libfreerdp-core/credssp.c

644 lines
16 KiB
C

/**
* FreeRDP: A Remote Desktop Protocol Client
* Credential Security Support Provider (CredSSP)
*
* Copyright 2010 Marc-Andre Moreau <marcandre.moreau@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _WIN32
#include <unistd.h>
#endif
#include <time.h>
#include "ntlmssp.h"
#include "credssp.h"
/**
* TSRequest ::= SEQUENCE {
* version [0] INTEGER,
* negoTokens [1] NegoData OPTIONAL,
* authInfo [2] OCTET STRING OPTIONAL,
* pubKeyAuth [3] OCTET STRING OPTIONAL
* }
*
* NegoData ::= SEQUENCE OF NegoDataItem
*
* NegoDataItem ::= SEQUENCE {
* negoToken [0] OCTET STRING
* }
*
* TSCredentials ::= SEQUENCE {
* credType [0] INTEGER,
* credentials [1] OCTET STRING
* }
*
* TSPasswordCreds ::= SEQUENCE {
* domainName [0] OCTET STRING,
* userName [1] OCTET STRING,
* password [2] OCTET STRING
* }
*
* TSSmartCardCreds ::= SEQUENCE {
* pin [0] OCTET STRING,
* cspData [1] TSCspDataDetail,
* userHint [2] OCTET STRING OPTIONAL,
* domainHint [3] OCTET STRING OPTIONAL
* }
*
* TSCspDataDetail ::= SEQUENCE {
* keySpec [0] INTEGER,
* cardName [1] OCTET STRING OPTIONAL,
* readerName [2] OCTET STRING OPTIONAL,
* containerName [3] OCTET STRING OPTIONAL,
* cspName [4] OCTET STRING OPTIONAL
* }
*
*/
/**
* Initialize NTLMSSP authentication module.
* @param credssp
*/
void credssp_ntlmssp_init(rdpCredssp* credssp)
{
NTLMSSP *ntlmssp = credssp->ntlmssp;
rdpSettings *settings = credssp->transport->settings;
ntlmssp_set_password(ntlmssp, settings->password);
ntlmssp_set_username(ntlmssp, settings->username);
if (settings->domain != NULL)
{
if (strlen(settings->domain) > 0)
{
ntlmssp_set_domain(ntlmssp, settings->domain);
}
}
else
{
ntlmssp_set_domain(ntlmssp, NULL);
}
ntlmssp_generate_client_challenge(ntlmssp);
ntlmssp_generate_random_session_key(ntlmssp);
ntlmssp_generate_exported_session_key(ntlmssp);
ntlmssp->ntlm_v2 = 0;
}
/**
* Get TLS public key.
* @param credssp
*/
int credssp_get_public_key(rdpCredssp* credssp)
{
int ret;
CryptoCert cert;
cert = tls_get_certificate(credssp->transport->tls);
if (cert == NULL)
{
printf("credssp_get_public_key: tls_get_certificate failed to return the server certificate.\n");
return 0;
}
if(tls_verify_certificate(cert,credssp->transport->settings->hostname))
tls_disconnect(credssp->transport->tls);
ret = crypto_cert_get_public_key(cert, &credssp->public_key);
crypto_cert_free(cert);
return ret;
}
/**
* Authenticate with server using CredSSP.
* @param credssp
* @return 1 if authentication is successful
*/
int credssp_authenticate(rdpCredssp* credssp)
{
NTLMSSP *ntlmssp = credssp->ntlmssp;
STREAM* s = stream_new(0);
uint8* negoTokenBuffer = (uint8*) xmalloc(2048);
credssp_ntlmssp_init(credssp);
if (credssp_get_public_key(credssp) == 0)
return 0;
/* NTLMSSP NEGOTIATE MESSAGE */
s->p = s->data = negoTokenBuffer;
ntlmssp_send(ntlmssp, s);
credssp->negoToken.data = s->data;
credssp->negoToken.length = s->p - s->data;
credssp_send(credssp, &credssp->negoToken, NULL, NULL);
/* NTLMSSP CHALLENGE MESSAGE */
if (credssp_recv(credssp, &credssp->negoToken, NULL, NULL) < 0)
return -1;
s->p = s->data = credssp->negoToken.data;
ntlmssp_recv(ntlmssp, s);
freerdp_blob_free(&credssp->negoToken);
/* NTLMSSP AUTHENTICATE MESSAGE */
s->p = s->data = negoTokenBuffer;
ntlmssp_send(ntlmssp, s);
/* The last NTLMSSP message is sent with the encrypted public key */
credssp->negoToken.data = s->data;
credssp->negoToken.length = s->p - s->data;
credssp_encrypt_public_key(credssp, &credssp->pubKeyAuth);
credssp_send(credssp, &credssp->negoToken, NULL, &credssp->pubKeyAuth);
/* Encrypted Public Key +1 */
if (credssp_recv(credssp, &credssp->negoToken, NULL, &credssp->pubKeyAuth) < 0)
return -1;
if (credssp_verify_public_key(credssp, &credssp->pubKeyAuth) == 0)
{
/* Failed to verify server public key echo */
return 0; /* DO NOT SEND CREDENTIALS! */
}
freerdp_blob_free(&credssp->negoToken);
freerdp_blob_free(&credssp->pubKeyAuth);
/* Send encrypted credentials */
credssp_encode_ts_credentials(credssp);
credssp_encrypt_ts_credentials(credssp, &credssp->authInfo);
credssp_send(credssp, NULL, &credssp->authInfo, NULL);
xfree(s);
return 1;
}
/**
* Encrypt TLS public key using CredSSP.
* @param credssp
* @param s
*/
void credssp_encrypt_public_key(rdpCredssp* credssp, rdpBlob* d)
{
uint8 *p;
uint8 signature[16];
rdpBlob encrypted_public_key;
NTLMSSP *ntlmssp = credssp->ntlmssp;
freerdp_blob_alloc(d, credssp->public_key.length + 16);
ntlmssp_encrypt_message(ntlmssp, &credssp->public_key, &encrypted_public_key, signature);
#ifdef WITH_DEBUG_NLA
printf("Public Key (length = %d)\n", credssp->public_key.length);
freerdp_hexdump(credssp->public_key.data, credssp->public_key.length);
printf("\n");
printf("Encrypted Public Key (length = %d)\n", encrypted_public_key.length);
freerdp_hexdump(encrypted_public_key.data, encrypted_public_key.length);
printf("\n");
printf("Signature\n");
freerdp_hexdump(signature, 16);
printf("\n");
#endif
p = (uint8*) d->data;
memcpy(p, signature, 16); /* Message Signature */
memcpy(&p[16], encrypted_public_key.data, encrypted_public_key.length); /* Encrypted Public Key */
freerdp_blob_free(&encrypted_public_key);
}
/**
* Verify TLS public key using CredSSP.
* @param credssp
* @param s
* @return 1 if verification is successful, 0 otherwise
*/
int credssp_verify_public_key(rdpCredssp* credssp, rdpBlob* d)
{
uint8 *p1, *p2;
uint8 *signature;
rdpBlob public_key;
rdpBlob encrypted_public_key;
signature = d->data;
encrypted_public_key.data = (void*) (signature + 16);
encrypted_public_key.length = d->length - 16;
ntlmssp_decrypt_message(credssp->ntlmssp, &encrypted_public_key, &public_key, signature);
p1 = (uint8*) credssp->public_key.data;
p2 = (uint8*) public_key.data;
p2[0]--;
if (memcmp(p1, p2, public_key.length) != 0)
{
printf("Could not verify server's public key echo\n");
return 0;
}
p2[0]++;
freerdp_blob_free(&public_key);
return 1;
}
/**
* Encrypt and sign TSCredentials structure.
* @param credssp
* @param s
*/
void credssp_encrypt_ts_credentials(rdpCredssp* credssp, rdpBlob* d)
{
uint8 *p;
uint8 signature[16];
rdpBlob encrypted_ts_credentials;
NTLMSSP *ntlmssp = credssp->ntlmssp;
freerdp_blob_alloc(d, credssp->ts_credentials.length + 16);
ntlmssp_encrypt_message(ntlmssp, &credssp->ts_credentials, &encrypted_ts_credentials, signature);
#ifdef WITH_DEBUG_NLA
printf("TSCredentials (length = %d)\n", credssp->ts_credentials.length);
freerdp_hexdump(credssp->ts_credentials.data, credssp->ts_credentials.length);
printf("\n");
printf("Encrypted TSCredentials (length = %d)\n", encrypted_ts_credentials.length);
freerdp_hexdump(encrypted_ts_credentials.data, encrypted_ts_credentials.length);
printf("\n");
printf("Signature\n");
freerdp_hexdump(signature, 16);
printf("\n");
#endif
p = (uint8*) d->data;
memcpy(p, signature, 16); /* Message Signature */
memcpy(&p[16], encrypted_ts_credentials.data, encrypted_ts_credentials.length); /* Encrypted TSCredentials */
freerdp_blob_free(&encrypted_ts_credentials);
}
int credssp_skip_ts_password_creds(rdpCredssp* credssp)
{
int length;
int ts_password_creds_length = 0;
length = ber_skip_octet_string(credssp->ntlmssp->domain.length);
length += ber_skip_contextual_tag(length);
ts_password_creds_length += length;
length = ber_skip_octet_string(credssp->ntlmssp->username.length);
length += ber_skip_contextual_tag(length);
ts_password_creds_length += length;
length = ber_skip_octet_string(credssp->ntlmssp->password.length);
length += ber_skip_contextual_tag(length);
ts_password_creds_length += length;
length = ber_skip_sequence(ts_password_creds_length);
return length;
}
void credssp_write_ts_password_creds(rdpCredssp* credssp, STREAM* s)
{
int length;
length = credssp_skip_ts_password_creds(credssp);
/* TSPasswordCreds (SEQUENCE) */
length = ber_get_content_length(length);
ber_write_sequence_tag(s, length);
/* [0] domainName (OCTET STRING) */
ber_write_contextual_tag(s, 0, credssp->ntlmssp->domain.length + 2, True);
ber_write_octet_string(s, credssp->ntlmssp->domain.data, credssp->ntlmssp->domain.length);
/* [1] userName (OCTET STRING) */
ber_write_contextual_tag(s, 1, credssp->ntlmssp->username.length + 2, True);
ber_write_octet_string(s, credssp->ntlmssp->username.data, credssp->ntlmssp->username.length);
/* [2] password (OCTET STRING) */
ber_write_contextual_tag(s, 2, credssp->ntlmssp->password.length + 2, True);
ber_write_octet_string(s, credssp->ntlmssp->password.data, credssp->ntlmssp->password.length);
}
int credssp_skip_ts_credentials(rdpCredssp* credssp)
{
int length;
int ts_password_creds_length;
int ts_credentials_length = 0;
length = ber_skip_integer(0);
length += ber_skip_contextual_tag(length);
ts_credentials_length += length;
ts_password_creds_length = credssp_skip_ts_password_creds(credssp);
length = ber_skip_octet_string(ts_password_creds_length);
length += ber_skip_contextual_tag(length);
ts_credentials_length += length;
length = ber_skip_sequence(ts_credentials_length);
return length;
}
void credssp_write_ts_credentials(rdpCredssp* credssp, STREAM* s)
{
int length;
int ts_password_creds_length;
length = credssp_skip_ts_credentials(credssp);
ts_password_creds_length = credssp_skip_ts_password_creds(credssp);
/* TSCredentials (SEQUENCE) */
length = ber_get_content_length(length);
length -= ber_write_sequence_tag(s, length);
/* [0] credType (INTEGER) */
length -= ber_write_contextual_tag(s, 0, 3, True);
length -= ber_write_integer(s, 1);
/* [1] credentials (OCTET STRING) */
length -= 1;
length -= ber_write_contextual_tag(s, 1, length, True);
length -= ber_write_octet_string_tag(s, ts_password_creds_length);
credssp_write_ts_password_creds(credssp, s);
}
/**
* Encode TSCredentials structure.
* @param credssp
*/
void credssp_encode_ts_credentials(rdpCredssp* credssp)
{
STREAM* s;
int length;
s = stream_new(0);
length = credssp_skip_ts_credentials(credssp);
freerdp_blob_alloc(&credssp->ts_credentials, length);
s->p = s->data = credssp->ts_credentials.data;
s->size = length;
credssp_write_ts_credentials(credssp, s);
}
int credssp_skip_nego_token(int length)
{
length = ber_skip_octet_string(length);
length += ber_skip_contextual_tag(length);
return length;
}
int credssp_skip_nego_tokens(int length)
{
length = credssp_skip_nego_token(length);
length += ber_skip_sequence_tag(length);
length += ber_skip_sequence_tag(length);
length += ber_skip_contextual_tag(length);
return length;
}
int credssp_skip_pub_key_auth(int length)
{
length = ber_skip_octet_string(length);
length += ber_skip_contextual_tag(length);
return length;
}
int credssp_skip_auth_info(int length)
{
length = ber_skip_octet_string(length);
length += ber_skip_contextual_tag(length);
return length;
}
int credssp_skip_ts_request(int length)
{
length += ber_skip_integer(2);
length += ber_skip_contextual_tag(3);
length += ber_skip_sequence_tag(length);
return length;
}
/**
* Send CredSSP message.
* @param credssp
* @param negoToken
* @param authInfo
* @param pubKeyAuth
*/
void credssp_send(rdpCredssp* credssp, rdpBlob* negoToken, rdpBlob* authInfo, rdpBlob* pubKeyAuth)
{
STREAM* s;
int length;
int ts_request_length;
int nego_tokens_length;
int pub_key_auth_length;
int auth_info_length;
nego_tokens_length = (negoToken != NULL) ? credssp_skip_nego_tokens(negoToken->length) : 0;
pub_key_auth_length = (pubKeyAuth != NULL) ? credssp_skip_pub_key_auth(pubKeyAuth->length) : 0;
auth_info_length = (authInfo != NULL) ? credssp_skip_auth_info(authInfo->length) : 0;
length = nego_tokens_length + pub_key_auth_length + auth_info_length;
ts_request_length = credssp_skip_ts_request(length);
s = stream_new(ts_request_length);
/* TSRequest */
length = ber_get_content_length(ts_request_length);
ber_write_sequence_tag(s, length); /* SEQUENCE */
ber_write_contextual_tag(s, 0, 3, True); /* [0] version */
ber_write_integer(s, 2); /* INTEGER */
/* [1] negoTokens (NegoData) */
if (nego_tokens_length > 0)
{
length = ber_get_content_length(nego_tokens_length);
length -= ber_write_contextual_tag(s, 1, length, True); /* NegoData */
length -= ber_write_sequence_tag(s, length); /* SEQUENCE OF NegoDataItem */
length -= ber_write_sequence_tag(s, length); /* NegoDataItem */
length -= ber_write_contextual_tag(s, 0, length, True); /* [0] negoToken */
ber_write_octet_string(s, negoToken->data, length); /* OCTET STRING */
}
/* [2] authInfo (OCTET STRING) */
if (auth_info_length > 0)
{
length = ber_get_content_length(auth_info_length);
length -= ber_write_contextual_tag(s, 2, length, True);
ber_write_octet_string(s, authInfo->data, authInfo->length);
}
/* [3] pubKeyAuth (OCTET STRING) */
if (pub_key_auth_length > 0)
{
length = ber_get_content_length(pub_key_auth_length);
length -= ber_write_contextual_tag(s, 3, length, True);
ber_write_octet_string(s, pubKeyAuth->data, length);
}
transport_write(credssp->transport, s);
}
/**
* Receive CredSSP message.
* @param credssp
* @param negoToken
* @param authInfo
* @param pubKeyAuth
* @return
*/
int credssp_recv(rdpCredssp* credssp, rdpBlob* negoToken, rdpBlob* authInfo, rdpBlob* pubKeyAuth)
{
STREAM* s;
int length;
int status;
uint32 version;
s = transport_recv_stream_init(credssp->transport, 2048);
status = transport_read(credssp->transport, s);
if (status < 0)
return -1;
/* TSRequest */
ber_read_sequence_tag(s, &length);
ber_read_contextual_tag(s, 0, &length, True);
ber_read_integer(s, &version);
/* [1] negoTokens (NegoData) */
if (ber_read_contextual_tag(s, 1, &length, True) != False)
{
ber_read_sequence_tag(s, &length); /* SEQUENCE OF NegoDataItem */
ber_read_sequence_tag(s, &length); /* NegoDataItem */
ber_read_contextual_tag(s, 0, &length, True); /* [0] negoToken */
ber_read_octet_string(s, &length); /* OCTET STRING */
freerdp_blob_alloc(negoToken, length);
stream_read(s, negoToken->data, length);
}
/* [2] authInfo (OCTET STRING) */
if (ber_read_contextual_tag(s, 2, &length, True) != False)
{
ber_read_octet_string(s, &length); /* OCTET STRING */
freerdp_blob_alloc(authInfo, length);
stream_read(s, authInfo->data, length);
}
/* [3] pubKeyAuth (OCTET STRING) */
if (ber_read_contextual_tag(s, 3, &length, True) != False)
{
ber_read_octet_string(s, &length); /* OCTET STRING */
freerdp_blob_alloc(pubKeyAuth, length);
stream_read(s, pubKeyAuth->data, length);
}
return 0;
}
/**
* Encrypt the given plain text using RC4 and the given key.
* @param key RC4 key
* @param length text length
* @param plaintext plain text
* @param ciphertext cipher text
*/
void credssp_rc4k(uint8* key, int length, uint8* plaintext, uint8* ciphertext)
{
CryptoRc4 rc4;
/* Initialize RC4 cipher with key */
rc4 = crypto_rc4_init((void*) key, 16);
/* Encrypt plaintext with key */
crypto_rc4(rc4, length, (void*) plaintext, (void*) ciphertext);
/* Free RC4 Cipher */
crypto_rc4_free(rc4);
}
/**
* Get current time, in tenths of microseconds since midnight of January 1, 1601.
* @param[out] timestamp 64-bit little-endian timestamp
*/
void credssp_current_time(uint8* timestamp)
{
uint64 time64;
/* Timestamp (8 bytes), represented as the number of tenths of microseconds since midnight of January 1, 1601 */
time64 = time(NULL) + 11644473600LL; /* Seconds since January 1, 1601 */
time64 *= 10000000; /* Convert timestamp to tenths of a microsecond */
memcpy(timestamp, &time64, 8); /* Copy into timestamp in little-endian */
}
/**
* Create new CredSSP state machine.
* @param transport
* @return new CredSSP state machine.
*/
rdpCredssp* credssp_new(rdpTransport* transport)
{
rdpCredssp* self;
self = (rdpCredssp*) xzalloc(sizeof(rdpCredssp));
if (self != NULL)
{
self->transport = transport;
self->send_seq_num = 0;
self->ntlmssp = ntlmssp_new();
}
return self;
}
/**
* Free CredSSP state machine.
* @param credssp
*/
void credssp_free(rdpCredssp* credssp)
{
if (credssp != NULL)
{
freerdp_blob_free(&credssp->public_key);
freerdp_blob_free(&credssp->ts_credentials);
ntlmssp_free(credssp->ntlmssp);
xfree(credssp);
}
}