/* * 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" #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 then 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 calc_ntlmv2_key(unsigned char 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 unsigned char *)constant, strlen(constant)+1); MD5Final(subkey, &ctx3); } enum ntlmssp_direction { NTLMSSP_SEND, NTLMSSP_RECEIVE }; static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_STATE *ntlmssp_state, const uchar *data, size_t length, const uchar *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; uchar seq_num[4]; uchar digest[16]; *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->ntlm2_send_seq_num, (unsigned int)length, (unsigned int)pdu_length)); SIVAL(seq_num, 0, ntlmssp_state->ntlm2_send_seq_num); ntlmssp_state->ntlm2_send_seq_num++; hmac_md5_init_limK_to_64(ntlmssp_state->send_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->ntlm2_recv_seq_num, (unsigned int)length, (unsigned int)pdu_length)); SIVAL(seq_num, 0, ntlmssp_state->ntlm2_recv_seq_num); ntlmssp_state->ntlm2_recv_seq_num++; hmac_md5_init_limK_to_64(ntlmssp_state->recv_sign_key, 16, &ctx); break; } dump_data_pw("pdu data ", whole_pdu, pdu_length); hmac_md5_update(seq_num, 4, &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: smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, digest, 8); break; case NTLMSSP_RECEIVE: smb_arc4_crypt(ntlmssp_state->recv_seal_arc4_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 { uint32 crc; crc = crc32_calc_buffer((const char *)data, length); if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) { return NT_STATUS_NO_MEMORY; } ntlmssp_state->ntlmv1_seq_num++; dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmv1_arc4_state, sizeof(ntlmssp_state->ntlmv1_arc4_state)); smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4); } return NT_STATUS_OK; } NTSTATUS ntlmssp_sign_packet(NTLMSSP_STATE *ntlmssp_state, const uchar *data, size_t length, const uchar *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(NTLMSSP_STATE *ntlmssp_state, const uchar *data, size_t length, const uchar *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 check 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(NTLMSSP_STATE *ntlmssp_state, uchar *data, size_t length, uchar *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) { /* The order of these two operations matters - we must first seal the packet, then seal the sequence number - this is becouse the send_seal_hash is not constant, but is is rather updated with each iteration */ NTSTATUS 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; } smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, data, length); if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) { smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, sig->data+4, 8); } } else { uint32 crc; crc = crc32_calc_buffer((const char *)data, length); if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) { 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 becouse the ntlmv1_arc4_state is not constant, but is is rather updated with each iteration */ dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state, sizeof(ntlmssp_state->ntlmv1_arc4_state)); smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, data, length); dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state, sizeof(ntlmssp_state->ntlmv1_arc4_state)); smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4); ntlmssp_state->ntlmv1_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(NTLMSSP_STATE *ntlmssp_state, uchar *data, size_t length, uchar *whole_pdu, size_t pdu_length, 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. */ smb_arc4_crypt(ntlmssp_state->recv_seal_arc4_state, data, length); dump_data_pw("ntlmv2 clear data\n", data, length); } else { smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_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(NTLMSSP_STATE *ntlmssp_state) { unsigned char p24[24]; TALLOC_CTX *mem_ctx; ZERO_STRUCT(p24); mem_ctx = talloc_init("weak_keys"); if (!mem_ctx) { return NT_STATUS_NO_MEMORY; } DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n")); debug_ntlmssp_flags(ntlmssp_state->neg_flags); if (ntlmssp_state->session_key.length < 8) { TALLOC_FREE(mem_ctx); DEBUG(3, ("NO session key, cannot intialise signing\n")); return NT_STATUS_NO_USER_SESSION_KEY; } 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; 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: TALLOC_FREE(mem_ctx); 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. */ if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) { ; } 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->send_sign_key, ntlmssp_state->session_key, send_sign_const); dump_data_pw("NTLMSSP send sign key:\n", ntlmssp_state->send_sign_key, 16); /* SEND: seal ARCFOUR pad */ calc_ntlmv2_key(ntlmssp_state->send_seal_key, weak_session_key, send_seal_const); dump_data_pw("NTLMSSP send seal key:\n", ntlmssp_state->send_seal_key, 16); smb_arc4_init(ntlmssp_state->send_seal_arc4_state, ntlmssp_state->send_seal_key, 16); dump_data_pw("NTLMSSP send seal arc4 state:\n", ntlmssp_state->send_seal_arc4_state, sizeof(ntlmssp_state->send_seal_arc4_state)); /* RECV: sign key */ calc_ntlmv2_key(ntlmssp_state->recv_sign_key, ntlmssp_state->session_key, recv_sign_const); dump_data_pw("NTLMSSP recv send sign key:\n", ntlmssp_state->recv_sign_key, 16); /* RECV: seal ARCFOUR pad */ calc_ntlmv2_key(ntlmssp_state->recv_seal_key, weak_session_key, recv_seal_const); dump_data_pw("NTLMSSP recv seal key:\n", ntlmssp_state->recv_seal_key, 16); smb_arc4_init(ntlmssp_state->recv_seal_arc4_state, ntlmssp_state->recv_seal_key, 16); dump_data_pw("NTLMSSP recv seal arc4 state:\n", ntlmssp_state->recv_seal_arc4_state, sizeof(ntlmssp_state->recv_seal_arc4_state)); ntlmssp_state->ntlm2_send_seq_num = 0; ntlmssp_state->ntlm2_recv_seq_num = 0; } else { #if 0 /* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */ DATA_BLOB weak_session_key = ntlmssp_state->session_key; /** 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. */ if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) { ; } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) { weak_session_key.length = 6; } else { /* forty bits */ weak_session_key.length = 5; } dump_data_pw("NTLMSSP weakend master key:\n", weak_session_key.data, weak_session_key.length); #endif DATA_BLOB weak_session_key = ntlmssp_weaken_keys(ntlmssp_state, mem_ctx); DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n")); smb_arc4_init(ntlmssp_state->ntlmv1_arc4_state, weak_session_key.data, weak_session_key.length); dump_data_pw("NTLMv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state, sizeof(ntlmssp_state->ntlmv1_arc4_state)); ntlmssp_state->ntlmv1_seq_num = 0; } TALLOC_FREE(mem_ctx); return NT_STATUS_OK; }