/* * Unix SMB/CIFS implementation. * Version 3.0 * NTLMSSP Signing routines * Copyright (C) Andrew Bartlett 2003-2005 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #include "ntlmssp.h" #include "../libcli/auth/libcli_auth.h" #define CLI_SIGN "session key to client-to-server signing key magic constant" #define CLI_SEAL "session key to client-to-server sealing key magic constant" #define SRV_SIGN "session key to server-to-client signing key magic constant" #define SRV_SEAL "session key to server-to-client sealing key magic constant" /** * Some notes on the NTLM2 code: * * NTLM2 is a AEAD system. This means that the data encrypted is not * all the data that is signed. In DCE-RPC case, the headers of the * DCE-RPC packets are also signed. This prevents some of the * fun-and-games one might have by changing them. * */ static void dump_arc4_state(const char *description, struct arcfour_state *state) { dump_data_pw(description, state->sbox, sizeof(state->sbox)); } static void calc_ntlmv2_key(uint8_t subkey[16], DATA_BLOB session_key, const char *constant) { struct MD5Context ctx3; MD5Init(&ctx3); MD5Update(&ctx3, session_key.data, session_key.length); MD5Update(&ctx3, (const uint8_t *)constant, strlen(constant)+1); MD5Final(subkey, &ctx3); } enum ntlmssp_direction { NTLMSSP_SEND, NTLMSSP_RECEIVE }; struct ntlmssp_crypt_direction { uint32_t seq_num; uint8_t sign_key[16]; struct arcfour_state seal_state; }; union ntlmssp_crypt_state { /* NTLM */ struct ntlmssp_crypt_direction ntlm; /* NTLM2 */ struct { struct ntlmssp_crypt_direction sending; struct ntlmssp_crypt_direction receiving; } ntlm2; }; static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *ntlmssp_state, const uint8_t *data, size_t length, const uint8_t *whole_pdu, size_t pdu_length, enum ntlmssp_direction direction, DATA_BLOB *sig, bool encrypt_sig) { if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { HMACMD5Context ctx; uint8_t digest[16]; uint8_t seq_num[4]; *sig = data_blob(NULL, NTLMSSP_SIG_SIZE); if (!sig->data) { return NT_STATUS_NO_MEMORY; } switch (direction) { case NTLMSSP_SEND: DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n", ntlmssp_state->crypt->ntlm2.sending.seq_num, (unsigned int)length, (unsigned int)pdu_length)); SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.sending.seq_num); ntlmssp_state->crypt->ntlm2.sending.seq_num++; hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.sending.sign_key, 16, &ctx); break; case NTLMSSP_RECEIVE: DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n", ntlmssp_state->crypt->ntlm2.receiving.seq_num, (unsigned int)length, (unsigned int)pdu_length)); SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.receiving.seq_num); ntlmssp_state->crypt->ntlm2.receiving.seq_num++; hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16, &ctx); break; } dump_data_pw("pdu data ", whole_pdu, pdu_length); hmac_md5_update(seq_num, sizeof(seq_num), &ctx); hmac_md5_update(whole_pdu, pdu_length, &ctx); hmac_md5_final(digest, &ctx); if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) { switch (direction) { case NTLMSSP_SEND: arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state, digest, 8); break; case NTLMSSP_RECEIVE: arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state, digest, 8); break; } } SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION); memcpy(sig->data + 4, digest, 8); memcpy(sig->data + 12, seq_num, 4); dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length); } else { bool ok; uint32_t crc; crc = crc32_calc_buffer(data, length); ok = msrpc_gen(ntlmssp_state, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->crypt->ntlm.seq_num); if (!ok) { return NT_STATUS_NO_MEMORY; } ntlmssp_state->crypt->ntlm.seq_num++; dump_arc4_state("ntlmssp hash: \n", &ntlmssp_state->crypt->ntlm.seal_state); arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state, sig->data+4, sig->length-4); } return NT_STATUS_OK; } NTSTATUS ntlmssp_sign_packet(struct ntlmssp_state *ntlmssp_state, const uint8_t *data, size_t length, const uint8_t *whole_pdu, size_t pdu_length, DATA_BLOB *sig) { NTSTATUS nt_status; if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) { DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n")); return NT_STATUS_INVALID_PARAMETER; } if (!ntlmssp_state->session_key.length) { DEBUG(3, ("NO session key, cannot check sign packet\n")); return NT_STATUS_NO_USER_SESSION_KEY; } nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data, length, whole_pdu, pdu_length, NTLMSSP_SEND, sig, true); return nt_status; } /** * Check the signature of an incoming packet * @note caller *must* check that the signature is the size it expects * */ NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state, const uint8_t *data, size_t length, const uint8_t *whole_pdu, size_t pdu_length, const DATA_BLOB *sig) { DATA_BLOB local_sig; NTSTATUS nt_status; if (!ntlmssp_state->session_key.length) { DEBUG(3, ("NO session key, cannot check packet signature\n")); return NT_STATUS_NO_USER_SESSION_KEY; } if (sig->length < 8) { DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n", (unsigned long)sig->length)); } nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data, length, whole_pdu, pdu_length, NTLMSSP_RECEIVE, &local_sig, true); if (!NT_STATUS_IS_OK(nt_status)) { DEBUG(0,("NTLMSSP packet sig creation failed with %s\n", nt_errstr(nt_status))); data_blob_free(&local_sig); return nt_status; } if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { if (local_sig.length != sig->length || memcmp(local_sig.data, sig->data, sig->length) != 0) { DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n")); dump_data(5, local_sig.data, local_sig.length); DEBUG(5, ("BAD SIG: got signature of\n")); dump_data(5, sig->data, sig->length); DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n")); data_blob_free(&local_sig); return NT_STATUS_ACCESS_DENIED; } } else { if (local_sig.length != sig->length || memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) { DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n")); dump_data(5, local_sig.data, local_sig.length); DEBUG(5, ("BAD SIG: got signature of\n")); dump_data(5, sig->data, sig->length); DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n")); data_blob_free(&local_sig); return NT_STATUS_ACCESS_DENIED; } } dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length); DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n")); data_blob_free(&local_sig); return NT_STATUS_OK; } /** * Seal data with the NTLMSSP algorithm * */ NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state, uint8_t *data, size_t length, const uint8_t *whole_pdu, size_t pdu_length, DATA_BLOB *sig) { if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) { DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n")); return NT_STATUS_INVALID_PARAMETER; } if (!ntlmssp_state->session_key.length) { DEBUG(3, ("NO session key, cannot seal packet\n")); return NT_STATUS_NO_USER_SESSION_KEY; } DEBUG(10,("ntlmssp_seal_data: seal\n")); dump_data_pw("ntlmssp clear data\n", data, length); if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { NTSTATUS nt_status; /* * The order of these two operations matters - we * must first seal the packet, then seal the * sequence number - this is because the * send_seal_hash is not constant, but is is rather * updated with each iteration */ nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data, length, whole_pdu, pdu_length, NTLMSSP_SEND, sig, false); if (!NT_STATUS_IS_OK(nt_status)) { return nt_status; } arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state, data, length); if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) { arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state, sig->data+4, 8); } } else { bool ok; uint32_t crc; crc = crc32_calc_buffer(data, length); ok = msrpc_gen(ntlmssp_state, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->crypt->ntlm.seq_num); if (!ok) { return NT_STATUS_NO_MEMORY; } /* * The order of these two operations matters - we * must first seal the packet, then seal the * sequence number - this is because the ntlmv1_arc4_state * is not constant, but is is rather updated with * each iteration */ dump_arc4_state("ntlmv1 arc4 state:\n", &ntlmssp_state->crypt->ntlm.seal_state); arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state, data, length); dump_arc4_state("ntlmv1 arc4 state:\n", &ntlmssp_state->crypt->ntlm.seal_state); arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state, sig->data+4, sig->length-4); ntlmssp_state->crypt->ntlm.seq_num++; } dump_data_pw("ntlmssp signature\n", sig->data, sig->length); dump_data_pw("ntlmssp sealed data\n", data, length); return NT_STATUS_OK; } /** * Unseal data with the NTLMSSP algorithm * */ NTSTATUS ntlmssp_unseal_packet(struct ntlmssp_state *ntlmssp_state, uint8_t *data, size_t length, const uint8_t *whole_pdu, size_t pdu_length, const DATA_BLOB *sig) { if (!ntlmssp_state->session_key.length) { DEBUG(3, ("NO session key, cannot unseal packet\n")); return NT_STATUS_NO_USER_SESSION_KEY; } DEBUG(10,("ntlmssp_unseal_packet: seal\n")); dump_data_pw("ntlmssp sealed data\n", data, length); if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { /* First unseal the data. */ arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state, data, length); dump_data_pw("ntlmv2 clear data\n", data, length); } else { arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state, data, length); dump_data_pw("ntlmv1 clear data\n", data, length); } return ntlmssp_check_packet(ntlmssp_state, data, length, whole_pdu, pdu_length, sig); } /** Initialise the state for NTLMSSP signing. */ NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state) { DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n")); debug_ntlmssp_flags(ntlmssp_state->neg_flags); if (ntlmssp_state->session_key.length < 8) { DEBUG(3, ("NO session key, cannot intialise signing\n")); return NT_STATUS_NO_USER_SESSION_KEY; } ntlmssp_state->crypt = talloc_zero(ntlmssp_state, union ntlmssp_crypt_state); if (ntlmssp_state->crypt == NULL) { return NT_STATUS_NO_MEMORY; } if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { DATA_BLOB weak_session_key = ntlmssp_state->session_key; const char *send_sign_const; const char *send_seal_const; const char *recv_sign_const; const char *recv_seal_const; uint8_t send_seal_key[16]; DATA_BLOB send_seal_blob = data_blob_const(send_seal_key, sizeof(send_seal_key)); uint8_t recv_seal_key[16]; DATA_BLOB recv_seal_blob = data_blob_const(recv_seal_key, sizeof(recv_seal_key)); switch (ntlmssp_state->role) { case NTLMSSP_CLIENT: send_sign_const = CLI_SIGN; send_seal_const = CLI_SEAL; recv_sign_const = SRV_SIGN; recv_seal_const = SRV_SEAL; break; case NTLMSSP_SERVER: send_sign_const = SRV_SIGN; send_seal_const = SRV_SEAL; recv_sign_const = CLI_SIGN; recv_seal_const = CLI_SEAL; break; default: return NT_STATUS_INTERNAL_ERROR; } /* * Weaken NTLMSSP keys to cope with down-level * clients, servers and export restrictions. * * We probably should have some parameters to * control this, once we get NTLM2 working. * * Key weakening was not performed on the master key * for NTLM2, but must be done on the encryption subkeys only. */ if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) { /* nothing to do */ } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) { weak_session_key.length = 7; } else { /* forty bits */ weak_session_key.length = 5; } dump_data_pw("NTLMSSP weakend master key:\n", weak_session_key.data, weak_session_key.length); /* SEND: sign key */ calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.sending.sign_key, ntlmssp_state->session_key, send_sign_const); dump_data_pw("NTLMSSP send sign key:\n", ntlmssp_state->crypt->ntlm2.sending.sign_key, 16); /* SEND: seal ARCFOUR pad */ calc_ntlmv2_key(send_seal_key, weak_session_key, send_seal_const); dump_data_pw("NTLMSSP send seal key:\n", send_seal_key, 16); arcfour_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state, &send_seal_blob); dump_arc4_state("NTLMSSP send seal arc4 state:\n", &ntlmssp_state->crypt->ntlm2.sending.seal_state); /* SEND: seq num */ ntlmssp_state->crypt->ntlm2.sending.seq_num = 0; /* RECV: sign key */ calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.receiving.sign_key, ntlmssp_state->session_key, recv_sign_const); dump_data_pw("NTLMSSP recv sign key:\n", ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16); /* RECV: seal ARCFOUR pad */ calc_ntlmv2_key(recv_seal_key, weak_session_key, recv_seal_const); dump_data_pw("NTLMSSP recv seal key:\n", recv_seal_key, 16); arcfour_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state, &recv_seal_blob); dump_arc4_state("NTLMSSP recv seal arc4 state:\n", &ntlmssp_state->crypt->ntlm2.receiving.seal_state); /* RECV: seq num */ ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0; } else { uint8_t weak_session_key[8]; DATA_BLOB seal_session_key = ntlmssp_state->session_key; bool do_weak = false; DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n")); /* * Key weakening not performed on the master key for NTLM2 * and does not occour for NTLM1. Therefore we only need * to do this for the LM_KEY. */ if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) { do_weak = true; } /* * Nothing to weaken. * We certainly don't want to 'extend' the length... */ if (seal_session_key.length < 16) { /* TODO: is this really correct? */ do_weak = false; } if (do_weak) { memcpy(weak_session_key, seal_session_key.data, 8); seal_session_key = data_blob_const(weak_session_key, 8); /* * LM key doesn't support 128 bit crypto, so this is * the best we can do. If you negotiate 128 bit, but * not 56, you end up with 40 bit... */ if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) { weak_session_key[7] = 0xa0; } else { /* forty bits */ weak_session_key[5] = 0xe5; weak_session_key[6] = 0x38; weak_session_key[7] = 0xb0; } } arcfour_init(&ntlmssp_state->crypt->ntlm.seal_state, &seal_session_key); dump_arc4_state("NTLMv1 arc4 state:\n", &ntlmssp_state->crypt->ntlm.seal_state); ntlmssp_state->crypt->ntlm.seq_num = 0; } return NT_STATUS_OK; }