diff options
Diffstat (limited to 'auth/ntlmssp/ntlmssp_sign.c')
| -rw-r--r-- | auth/ntlmssp/ntlmssp_sign.c | 694 |
1 files changed, 694 insertions, 0 deletions
diff --git a/auth/ntlmssp/ntlmssp_sign.c b/auth/ntlmssp/ntlmssp_sign.c new file mode 100644 index 0000000000..019ea3ce3b --- /dev/null +++ b/auth/ntlmssp/ntlmssp_sign.c @@ -0,0 +1,694 @@ +/* + * 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 "../auth/ntlmssp/ntlmssp.h" +#include "../libcli/auth/libcli_auth.h" +#include "../lib/crypto/md5.h" +#include "../lib/crypto/hmacmd5.h" +#include "../lib/crypto/crc32.h" +#include "../auth/ntlmssp/ntlmssp_private.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 +}; + +static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *ntlmssp_state, + TALLOC_CTX *sig_mem_ctx, + 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_talloc(sig_mem_ctx, 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 { + NTSTATUS status; + uint32_t crc; + + crc = crc32_calc_buffer(data, length); + + status = msrpc_gen(sig_mem_ctx, + sig, "dddd", + NTLMSSP_SIGN_VERSION, 0, crc, + ntlmssp_state->crypt->ntlm.seq_num); + if (!NT_STATUS_IS_OK(status)) { + return status; + } + + 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, + TALLOC_CTX *sig_mem_ctx, + 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, + sig_mem_ctx, + 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; + TALLOC_CTX *tmp_ctx; + + 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)); + } + + tmp_ctx = talloc_new(ntlmssp_state); + if (!tmp_ctx) { + return NT_STATUS_NO_MEMORY; + } + + nt_status = ntlmssp_make_packet_signature(ntlmssp_state, + tmp_ctx, + 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))); + talloc_free(tmp_ctx); + 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")); + talloc_free(tmp_ctx); + 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")); + talloc_free(tmp_ctx); + 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")); + + talloc_free(tmp_ctx); + return NT_STATUS_OK; +} + +/** + * Seal data with the NTLMSSP algorithm + * + */ + +NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state, + TALLOC_CTX *sig_mem_ctx, + 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, + sig_mem_ctx, + 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 { + NTSTATUS status; + uint32_t crc; + + crc = crc32_calc_buffer(data, length); + + status = msrpc_gen(sig_mem_ctx, + sig, "dddd", + NTLMSSP_SIGN_VERSION, 0, crc, + ntlmssp_state->crypt->ntlm.seq_num); + if (!NT_STATUS_IS_OK(status)) { + return status; + } + + /* + * 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) +{ + NTSTATUS status; + 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); + } + status = ntlmssp_check_packet(ntlmssp_state, + data, length, + whole_pdu, pdu_length, + sig); + + if (!NT_STATUS_IS_OK(status)) { + DEBUG(1,("NTLMSSP packet check for unseal failed due to invalid signature on %llu bytes of input:\n", + (unsigned long long)length)); + } + return status; +} + +NTSTATUS ntlmssp_wrap(struct ntlmssp_state *ntlmssp_state, + TALLOC_CTX *out_mem_ctx, + const DATA_BLOB *in, + DATA_BLOB *out) +{ + NTSTATUS nt_status; + DATA_BLOB sig; + + if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) { + *out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE); + if (!out->data) { + return NT_STATUS_NO_MEMORY; + } + memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length); + + nt_status = ntlmssp_seal_packet(ntlmssp_state, out_mem_ctx, + out->data + NTLMSSP_SIG_SIZE, + out->length - NTLMSSP_SIG_SIZE, + out->data + NTLMSSP_SIG_SIZE, + out->length - NTLMSSP_SIG_SIZE, + &sig); + + if (NT_STATUS_IS_OK(nt_status)) { + memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE); + talloc_free(sig.data); + } + return nt_status; + + } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) { + + *out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE); + if (!out->data) { + return NT_STATUS_NO_MEMORY; + } + memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length); + + nt_status = ntlmssp_sign_packet(ntlmssp_state, out_mem_ctx, + out->data + NTLMSSP_SIG_SIZE, + out->length - NTLMSSP_SIG_SIZE, + out->data + NTLMSSP_SIG_SIZE, + out->length - NTLMSSP_SIG_SIZE, + &sig); + + if (NT_STATUS_IS_OK(nt_status)) { + memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE); + talloc_free(sig.data); + } + return nt_status; + } else { + *out = data_blob_talloc(out_mem_ctx, in->data, in->length); + if (!out->data) { + return NT_STATUS_NO_MEMORY; + } + return NT_STATUS_OK; + } +} + +NTSTATUS ntlmssp_unwrap(struct ntlmssp_state *ntlmssp_state, + TALLOC_CTX *out_mem_ctx, + const DATA_BLOB *in, + DATA_BLOB *out) +{ + DATA_BLOB sig; + + if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) { + if (in->length < NTLMSSP_SIG_SIZE) { + return NT_STATUS_INVALID_PARAMETER; + } + sig.data = in->data; + sig.length = NTLMSSP_SIG_SIZE; + + *out = data_blob_talloc(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE); + + return ntlmssp_unseal_packet(ntlmssp_state, + out->data, out->length, + out->data, out->length, + &sig); + + } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) { + NTSTATUS status; + struct ntlmssp_crypt_direction save_direction; + + if (in->length < NTLMSSP_SIG_SIZE) { + return NT_STATUS_INVALID_PARAMETER; + } + sig.data = in->data; + sig.length = NTLMSSP_SIG_SIZE; + *out = data_blob_talloc(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE); + + if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { + save_direction = ntlmssp_state->crypt->ntlm2.receiving; + } else { + save_direction = ntlmssp_state->crypt->ntlm; + } + + status = ntlmssp_check_packet(ntlmssp_state, + out->data, out->length, + out->data, out->length, + &sig); + if (!NT_STATUS_IS_OK(status)) { + NTSTATUS check_status = status; + /* + * The Windows LDAP libraries seems to have a bug + * and always use sealing even if only signing was + * negotiated. So we need to fallback. + */ + + if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) { + ntlmssp_state->crypt->ntlm2.receiving = save_direction; + } else { + ntlmssp_state->crypt->ntlm = save_direction; + } + + status = ntlmssp_unseal_packet(ntlmssp_state, + out->data, + out->length, + out->data, + out->length, + &sig); + if (NT_STATUS_IS_OK(status)) { + ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL; + } else { + status = check_status; + } + } + + if (!NT_STATUS_IS_OK(status)) { + DEBUG(1, ("NTLMSSP packet check for unwrap failed due to invalid signature\n")); + } + return status; + } else { + *out = data_blob_talloc(out_mem_ctx, in->data, in->length); + if (!out->data) { + return NT_STATUS_NO_MEMORY; + } + return NT_STATUS_OK; + } +} + +/** + 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; +} |