void rdp_write_header(rdpRdp* rdp, STREAM* s, uint16 length, uint16 channel_id)
{
int body_length;
enum DomainMCSPDU MCSPDU;
MCSPDU = (rdp->settings->server_mode) ? DomainMCSPDU_SendDataIndication : DomainMCSPDU_SendDataRequest;
if ((rdp->sec_flags & SEC_ENCRYPT) && (rdp->settings->encryption_method == ENCRYPTION_METHOD_FIPS))
{
int pad;
body_length = length - RDP_PACKET_HEADER_MAX_LENGTH - 16;
pad = 8 - (body_length % 8);
if (pad != 8)
length += pad;
}
mcs_write_domain_mcspdu_header(s, MCSPDU, length, 0);
per_write_integer16(s, rdp->mcs->user_id, MCS_BASE_CHANNEL_ID); /* initiator */
per_write_integer16(s, channel_id, 0); /* channelId */
stream_write_uint8(s, 0x70); /* dataPriority + segmentation */
/*
* We always encode length in two bytes, eventhough we could use
* only one byte if length <= 0x7F. It is just easier that way,
* because we can leave room for fixed-length header, store all
* the data first and then store the header.
*/
length = (length - RDP_PACKET_HEADER_MAX_LENGTH) | 0x8000;
stream_write_uint16_be(s, length); /* userData (OCTET_STRING) */
}
void rdp_write_header(rdpRdp* rdp, STREAM* s, uint16 length, uint16 channel_id)
{
int body_length;
enum DomainMCSPDU MCSPDU;
MCSPDU = (rdp->settings->server_mode) ? DomainMCSPDU_SendDataIndication : DomainMCSPDU_SendDataRequest;
if ((rdp->sec_flags & SEC_ENCRYPT) && (rdp->settings->encryption_method == ENCRYPTION_METHOD_FIPS))
{
int pad;
body_length = length - RDP_PACKET_HEADER_LENGTH - 16;
pad = 8 - (body_length % 8);
if (pad != 8)
length += pad;
}
mcs_write_domain_mcspdu_header(s, MCSPDU, length, 0);
per_write_integer16(s, rdp->mcs->user_id, MCS_BASE_CHANNEL_ID); /* initiator */
per_write_integer16(s, channel_id, 0); /* channelId */
stream_write_uint8(s, 0x70); /* dataPriority + segmentation */
length = (length - RDP_PACKET_HEADER_LENGTH) | 0x8000;
stream_write_uint16_be(s, length); /* userData (OCTET_STRING) */
}
void rdp_write_header(rdpRdp* rdp, STREAM* s, int length)
{
mcs_write_domain_mcspdu_header(s, DomainMCSPDU_SendDataRequest, length);
per_write_integer16(s, rdp->mcs->user_id, MCS_BASE_CHANNEL_ID); /* initiator */
per_write_integer16(s, MCS_GLOBAL_CHANNEL_ID, 0); /* channelId */
stream_write_uint8(s, 0x70); /* dataPriority + segmentation */
per_write_length(s, length - RDP_PACKET_HEADER_LENGTH); /* userData (OCTET_STRING) */
}
void gcc_write_conference_create_response(wStream* s, wStream* userData)
{
/* ConnectData */
per_write_choice(s, 0);
per_write_object_identifier(s, t124_02_98_oid);
/* ConnectData::connectPDU (OCTET_STRING) */
/* This length MUST be ignored by the client according to [MS-RDPBCGR] */
per_write_length(s, 0x2A);
/* ConnectGCCPDU */
per_write_choice(s, 0x14);
/* ConferenceCreateResponse::nodeID (UserID) */
per_write_integer16(s, 0x79F3, 1001);
/* ConferenceCreateResponse::tag (INTEGER) */
per_write_integer(s, 1);
/* ConferenceCreateResponse::result (ENUMERATED) */
per_write_enumerated(s, 0, MCS_Result_enum_length);
/* number of UserData sets */
per_write_number_of_sets(s, 1);
/* UserData::value present + select h221NonStandard (1) */
per_write_choice(s, 0xC0);
/* h221NonStandard */
per_write_octet_string(s, h221_sc_key, 4, 4); /* h221NonStandard, server-to-client H.221 key, "McDn" */
/* userData (OCTET_STRING) */
per_write_octet_string(s, userData->buffer, Stream_GetPosition(userData), 0); /* array of server data blocks */
}
void gcc_write_conference_create_response(STREAM* s, STREAM* user_data)
{
/* ConnectData */
per_write_choice(s, 0);
per_write_object_identifier(s, t124_02_98_oid);
/* ConnectData::connectPDU (OCTET_STRING) */
per_write_length(s, stream_get_length(user_data) + 2);
/* ConnectGCCPDU */
per_write_choice(s, 0x14);
/* ConferenceCreateResponse::nodeID (UserID) */
per_write_integer16(s, 0x79F3, 1001);
/* ConferenceCreateResponse::tag (INTEGER) */
per_write_integer(s, 1);
/* ConferenceCreateResponse::result (ENUMERATED) */
per_write_enumerated(s, 0, MCS_Result_enum_length);
/* number of UserData sets */
per_write_number_of_sets(s, 1);
/* UserData::value present + select h221NonStandard (1) */
per_write_choice(s, 0xC0);
/* h221NonStandard */
per_write_octet_string(s, h221_sc_key, 4, 4); /* h221NonStandard, server-to-client H.221 key, "McDn" */
/* userData (OCTET_STRING) */
per_write_octet_string(s, user_data->data, stream_get_length(user_data), 0); /* array of server data blocks */
}
static boolean rdp_establish_keys(rdpRdp* rdp)
{
uint8 client_random[32];
uint8 crypt_client_random[256 + 8];
uint32 key_len;
uint8* mod;
uint8* exp;
uint32 length;
STREAM* s;
if (rdp->settings->encryption == False)
{
/* no RDP encryption */
return True;
}
/* encrypt client random */
memset(crypt_client_random, 0, sizeof(crypt_client_random));
memset(client_random, 0x5e, 32);
crypto_nonce(client_random, 32);
key_len = rdp->settings->server_cert->cert_info.modulus.length;
mod = rdp->settings->server_cert->cert_info.modulus.data;
exp = rdp->settings->server_cert->cert_info.exponent;
crypto_rsa_encrypt(client_random, 32, key_len, mod, exp, crypt_client_random);
/* send crypt client random to server */
length = 7 + 8 + 4 + 4 + key_len + 8;
s = transport_send_stream_init(rdp->mcs->transport, length);
tpkt_write_header(s, length);
tpdu_write_header(s, 2, 0xf0);
per_write_choice(s, DomainMCSPDU_SendDataRequest << 2);
per_write_integer16(s, rdp->mcs->user_id, MCS_BASE_CHANNEL_ID);
per_write_integer16(s, MCS_GLOBAL_CHANNEL_ID, 0);
stream_write_uint8(s, 0x70);
length = (4 + 4 + key_len + 8) | 0x8000;
stream_write_uint16_be(s, length);
stream_write_uint32(s, 1); /* SEC_CLIENT_RANDOM */
length = key_len + 8;
stream_write_uint32(s, length);
memcpy(s->p, crypt_client_random, length);
stream_seek(s, length);
if (transport_write(rdp->mcs->transport, s) < 0)
{
return False;
}
/* now calculate encrypt / decrypt and update keys */
if (!security_establish_keys(client_random, rdp))
{
return False;
}
rdp->do_crypt = True;
if (rdp->settings->encryption_method == ENCRYPTION_METHOD_FIPS)
{
uint8 fips_ivec[8] = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
rdp->fips_encrypt = crypto_des3_encrypt_init(rdp->fips_encrypt_key, fips_ivec);
rdp->fips_decrypt = crypto_des3_decrypt_init(rdp->fips_decrypt_key, fips_ivec);
rdp->fips_hmac = crypto_hmac_new();
return True;
}
rdp->rc4_decrypt_key = crypto_rc4_init(rdp->decrypt_key, rdp->rc4_key_len);
rdp->rc4_encrypt_key = crypto_rc4_init(rdp->encrypt_key, rdp->rc4_key_len);
return True;
}