From 6af15943c6f868d08945d0ca993506c17107fbd4 Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Mon, 9 Mar 2009 09:50:36 +0100 Subject: s3:libsmb: use new simplified smb_signing code for the client side We store the seqnum/mid mapping in the cli_request structure for async requests and in the cli_state structure for sync calls. We skip the signing check for oplock requests while waiting for async requests coming in. metze --- source3/libsmb/clisigning.c | 650 +++----------------------------------------- 1 file changed, 32 insertions(+), 618 deletions(-) (limited to 'source3/libsmb/clisigning.c') diff --git a/source3/libsmb/clisigning.c b/source3/libsmb/clisigning.c index 6644bc0d60..0d0e926e6c 100644 --- a/source3/libsmb/clisigning.c +++ b/source3/libsmb/clisigning.c @@ -1,8 +1,9 @@ -/* +/* Unix SMB/CIFS implementation. SMB Signing Code Copyright (C) Jeremy Allison 2003. Copyright (C) Andrew Bartlett 2002-2003 + Copyright (C) Stefan Metzmacher 2009 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 @@ -20,654 +21,67 @@ #include "includes.h" -/* Lookup a packet's MID (multiplex id) and figure out it's sequence number */ -struct outstanding_packet_lookup { - struct outstanding_packet_lookup *prev, *next; - uint16 mid; - uint32 reply_seq_num; - bool can_delete; /* Set to False in trans state. */ -}; - -struct smb_basic_signing_context { - DATA_BLOB mac_key; - uint32 send_seq_num; - struct outstanding_packet_lookup *outstanding_packet_list; -}; - -static bool store_sequence_for_reply(struct outstanding_packet_lookup **list, - uint16 mid, uint32 reply_seq_num) -{ - struct outstanding_packet_lookup *t; - - /* Ensure we only add a mid once. */ - for (t = *list; t; t = t->next) { - if (t->mid == mid) { - return False; - } - } - - t = SMB_XMALLOC_P(struct outstanding_packet_lookup); - ZERO_STRUCTP(t); - - t->mid = mid; - t->reply_seq_num = reply_seq_num; - t->can_delete = True; - - /* - * Add to the *start* of the list not the end of the list. - * This ensures that the *last* send sequence with this mid - * is returned by preference. - * This can happen if the mid wraps and one of the early - * mid numbers didn't get a reply and is still lurking on - * the list. JRA. Found by Fran Fabrizio . - */ - - DLIST_ADD(*list, t); - DEBUG(10,("store_sequence_for_reply: stored seq = %u mid = %u\n", - (unsigned int)reply_seq_num, (unsigned int)mid )); - return True; -} - -static bool get_sequence_for_reply(struct outstanding_packet_lookup **list, - uint16 mid, uint32 *reply_seq_num) -{ - struct outstanding_packet_lookup *t; - - for (t = *list; t; t = t->next) { - if (t->mid == mid) { - *reply_seq_num = t->reply_seq_num; - DEBUG(10,("get_sequence_for_reply: found seq = %u mid = %u\n", - (unsigned int)t->reply_seq_num, (unsigned int)t->mid )); - if (t->can_delete) { - DLIST_REMOVE(*list, t); - SAFE_FREE(t); - } - return True; - } - } - return False; -} - -static bool set_sequence_can_delete_flag(struct outstanding_packet_lookup **list, uint16 mid, bool can_delete_entry) -{ - struct outstanding_packet_lookup *t; - - for (t = *list; t; t = t->next) { - if (t->mid == mid) { - t->can_delete = can_delete_entry; - return True; - } - } - return False; -} - -/*********************************************************** - SMB signing - Common code before we set a new signing implementation -************************************************************/ - -static bool cli_set_smb_signing_common(struct cli_state *cli) -{ - if (!cli->sign_info.allow_smb_signing) { - return False; - } - - if (!cli->sign_info.negotiated_smb_signing - && !cli->sign_info.mandatory_signing) { - return False; - } - - if (cli->sign_info.doing_signing) { - return False; - } - - if (cli->sign_info.free_signing_context) - cli->sign_info.free_signing_context(&cli->sign_info); - - /* These calls are INCOMPATIBLE with SMB signing */ - cli->readbraw_supported = False; - cli->writebraw_supported = False; - - return True; -} - -/*********************************************************** - SMB signing - Common code for 'real' implementations -************************************************************/ - -static bool set_smb_signing_real_common(struct smb_sign_info *si) -{ - if (si->mandatory_signing) { - DEBUG(5, ("Mandatory SMB signing enabled!\n")); - } - - si->doing_signing = True; - DEBUG(5, ("SMB signing enabled!\n")); - - return True; -} - -static void mark_packet_signed(char *outbuf) -{ - uint16 flags2; - flags2 = SVAL(outbuf,smb_flg2); - flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES; - SSVAL(outbuf,smb_flg2, flags2); -} - -/*********************************************************** - SMB signing - NULL implementation - calculate a MAC to send. -************************************************************/ - -static void null_sign_outgoing_message(char *outbuf, struct smb_sign_info *si) -{ - /* we can't zero out the sig, as we might be trying to send a - session request - which is NBT-level, not SMB level and doesn't - have the field */ - return; -} - -/*********************************************************** - SMB signing - NULL implementation - check a MAC sent by server. -************************************************************/ - -static bool null_check_incoming_message(const char *inbuf, - struct smb_sign_info *si, - bool must_be_ok) -{ - return True; -} - -/*********************************************************** - SMB signing - NULL implementation - free signing context -************************************************************/ - -static void null_free_signing_context(struct smb_sign_info *si) -{ - return; -} - -/** - SMB signing - NULL implementation - setup the MAC key. - - @note Used as an initialisation only - it will not correctly - shut down a real signing mechanism -*/ - -static bool null_set_signing(struct smb_sign_info *si) -{ - si->signing_context = NULL; - - si->sign_outgoing_message = null_sign_outgoing_message; - si->check_incoming_message = null_check_incoming_message; - si->free_signing_context = null_free_signing_context; - - return True; -} - -/** - * Free the signing context - */ - -static void free_signing_context(struct smb_sign_info *si) -{ - if (si->free_signing_context) { - si->free_signing_context(si); - si->signing_context = NULL; - } - - null_set_signing(si); -} - - -static bool signing_good(const char *inbuf, struct smb_sign_info *si, - bool good, uint32 seq, bool must_be_ok) -{ - if (good) { - - if (!si->doing_signing) { - si->doing_signing = True; - } - - if (!si->seen_valid) { - si->seen_valid = True; - } - - } else { - if (!si->mandatory_signing && !si->seen_valid) { - - if (!must_be_ok) { - return True; - } - /* Non-mandatory signing - just turn off if this is the first bad packet.. */ - DEBUG(5, ("srv_check_incoming_message: signing negotiated but not required and peer\n" - "isn't sending correct signatures. Turning off.\n")); - si->negotiated_smb_signing = False; - si->allow_smb_signing = False; - si->doing_signing = False; - free_signing_context(si); - return True; - } else if (!must_be_ok) { - /* This packet is known to be unsigned */ - return True; - } else { - /* Mandatory signing or bad packet after signing started - fail and disconnect. */ - if (seq) - DEBUG(0, ("signing_good: BAD SIG: seq %u\n", (unsigned int)seq)); - return False; - } - } - return True; -} - -/*********************************************************** - SMB signing - Simple implementation - calculate a MAC on the packet -************************************************************/ - -static void simple_packet_signature(struct smb_basic_signing_context *data, - const uchar *buf, uint32 seq_number, - unsigned char calc_md5_mac[16]) -{ - const size_t offset_end_of_sig = (smb_ss_field + 8); - unsigned char sequence_buf[8]; - struct MD5Context md5_ctx; -#if 0 - /* JRA - apparently this is incorrect. */ - unsigned char key_buf[16]; -#endif - - /* - * Firstly put the sequence number into the first 4 bytes. - * and zero out the next 4 bytes. - * - * We do this here, to avoid modifying the packet. - */ - - DEBUG(10,("simple_packet_signature: sequence number %u\n", seq_number )); - - SIVAL(sequence_buf, 0, seq_number); - SIVAL(sequence_buf, 4, 0); - - /* Calculate the 16 byte MAC - but don't alter the data in the - incoming packet. - - This makes for a bit of fussing about, but it's not too bad. - */ - MD5Init(&md5_ctx); - - /* intialise with the key */ - MD5Update(&md5_ctx, data->mac_key.data, data->mac_key.length); -#if 0 - /* JRA - apparently this is incorrect. */ - /* NB. When making and verifying SMB signatures, Windows apparently - zero-pads the key to 128 bits if it isn't long enough. - From Nalin Dahyabhai */ - if (data->mac_key.length < sizeof(key_buf)) { - memset(key_buf, 0, sizeof(key_buf)); - MD5Update(&md5_ctx, key_buf, sizeof(key_buf) - data->mac_key.length); - } -#endif - - /* copy in the first bit of the SMB header */ - MD5Update(&md5_ctx, buf + 4, smb_ss_field - 4); - - /* copy in the sequence number, instead of the signature */ - MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf)); - - /* copy in the rest of the packet in, skipping the signature */ - MD5Update(&md5_ctx, buf + offset_end_of_sig, - smb_len(buf) - (offset_end_of_sig - 4)); - - /* calculate the MD5 sig */ - MD5Final(calc_md5_mac, &md5_ctx); -} - - -/*********************************************************** - SMB signing - Client implementation - send the MAC. -************************************************************/ - -static void client_sign_outgoing_message(char *outbuf, struct smb_sign_info *si) -{ - unsigned char calc_md5_mac[16]; - struct smb_basic_signing_context *data = - (struct smb_basic_signing_context *)si->signing_context; - - if (!si->doing_signing) - return; - - /* JRA Paranioa test - we should be able to get rid of this... */ - if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) { - DEBUG(1, ("client_sign_outgoing_message: Logic error. Can't check signature on short packet! smb_len = %u\n", - smb_len(outbuf) )); - abort(); - } - - /* mark the packet as signed - BEFORE we sign it...*/ - mark_packet_signed(outbuf); - - simple_packet_signature(data, (const unsigned char *)outbuf, - data->send_seq_num, calc_md5_mac); - - DEBUG(10, ("client_sign_outgoing_message: sent SMB signature of\n")); - dump_data(10, calc_md5_mac, 8); - - memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8); - -/* cli->outbuf[smb_ss_field+2]=0; - Uncomment this to test if the remote server actually verifies signatures...*/ - - /* Instead of re-introducing the trans_info_conect we - used to have here, we use the fact that during a - SMBtrans/SMBtrans2/SMBnttrans send that the mid stays - constant. This means that calling store_sequence_for_reply() - will return False for all trans secondaries, as the mid is already - on the stored sequence list. As the send_seqence_number must - remain constant for all primary+secondary trans sends, we - only increment the send sequence number when we successfully - add a new entry to the outstanding sequence list. This means - I can isolate the fix here rather than re-adding the trans - signing on/off calls in libsmb/clitrans2.c JRA. - */ - - if (store_sequence_for_reply(&data->outstanding_packet_list, SVAL(outbuf,smb_mid), data->send_seq_num + 1)) { - data->send_seq_num += 2; - } -} - -/*********************************************************** - SMB signing - Client implementation - check a MAC sent by server. -************************************************************/ - -static bool client_check_incoming_message(const char *inbuf, - struct smb_sign_info *si, - bool must_be_ok) -{ - bool good; - uint32 reply_seq_number; - unsigned char calc_md5_mac[16]; - unsigned char *server_sent_mac; - - struct smb_basic_signing_context *data = - (struct smb_basic_signing_context *)si->signing_context; - - if (!si->doing_signing) - return True; - - if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) { - DEBUG(1, ("client_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf))); - return False; - } - - if (!get_sequence_for_reply(&data->outstanding_packet_list, SVAL(inbuf, smb_mid), &reply_seq_number)) { - DEBUG(1, ("client_check_incoming_message: received message " - "with mid %u with no matching send record.\n", (unsigned int)SVAL(inbuf, smb_mid) )); - return False; - } - - simple_packet_signature(data, (const unsigned char *)inbuf, - reply_seq_number, calc_md5_mac); - - server_sent_mac = (unsigned char *)&inbuf[smb_ss_field]; - good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0); - - if (!good) { - DEBUG(5, ("client_check_incoming_message: BAD SIG: wanted SMB signature of\n")); - dump_data(5, calc_md5_mac, 8); - - DEBUG(5, ("client_check_incoming_message: BAD SIG: got SMB signature of\n")); - dump_data(5, server_sent_mac, 8); -#if 1 /* JRATEST */ - { - int i; - for (i = -5; i < 5; i++) { - simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number+i, calc_md5_mac); - if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) { - DEBUG(0,("client_check_incoming_message: out of seq. seq num %u matches. \ -We were expecting seq %u\n", reply_seq_number+i, reply_seq_number )); - break; - } - } - } -#endif /* JRATEST */ - - } else { - DEBUG(10, ("client_check_incoming_message: seq %u: got good SMB signature of\n", (unsigned int)reply_seq_number)); - dump_data(10, server_sent_mac, 8); - } - return signing_good(inbuf, si, good, reply_seq_number, must_be_ok); -} - -/*********************************************************** - SMB signing - Simple implementation - free signing context -************************************************************/ - -static void simple_free_signing_context(struct smb_sign_info *si) -{ - struct smb_basic_signing_context *data = - (struct smb_basic_signing_context *)si->signing_context; - struct outstanding_packet_lookup *list; - struct outstanding_packet_lookup *next; - - for (list = data->outstanding_packet_list; list; list = next) { - next = list->next; - DLIST_REMOVE(data->outstanding_packet_list, list); - SAFE_FREE(list); - } - - data_blob_free(&data->mac_key); - - SAFE_FREE(si->signing_context); - - return; -} - -/*********************************************************** - SMB signing - Simple implementation - setup the MAC key. -************************************************************/ - bool cli_simple_set_signing(struct cli_state *cli, const DATA_BLOB user_session_key, const DATA_BLOB response) { - struct smb_basic_signing_context *data; - - if (!user_session_key.length) - return False; - - if (!cli_set_smb_signing_common(cli)) { - return False; - } - - if (!set_smb_signing_real_common(&cli->sign_info)) { - return False; - } - - data = SMB_XMALLOC_P(struct smb_basic_signing_context); - memset(data, '\0', sizeof(*data)); - - cli->sign_info.signing_context = data; - - data->mac_key = data_blob(NULL, response.length + user_session_key.length); - - memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length); - - DEBUG(10, ("cli_simple_set_signing: user_session_key\n")); - dump_data(10, user_session_key.data, user_session_key.length); + bool ok; - if (response.length) { - memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length); - DEBUG(10, ("cli_simple_set_signing: response_data\n")); - dump_data(10, response.data, response.length); - } else { - DEBUG(10, ("cli_simple_set_signing: NULL response_data\n")); + ok = smb_signing_activate(cli->signing_state, + user_session_key, + response); + if (!ok) { + return false; } - dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length); + cli->readbraw_supported = false; + cli->writebraw_supported = false; - /* Initialise the sequence number */ - data->send_seq_num = 0; - - /* Initialise the list of outstanding packets */ - data->outstanding_packet_list = NULL; - - cli->sign_info.sign_outgoing_message = client_sign_outgoing_message; - cli->sign_info.check_incoming_message = client_check_incoming_message; - cli->sign_info.free_signing_context = simple_free_signing_context; - - return True; -} - -/*********************************************************** - SMB signing - TEMP implementation - calculate a MAC to send. -************************************************************/ - -static void temp_sign_outgoing_message(char *outbuf, struct smb_sign_info *si) -{ - /* mark the packet as signed - BEFORE we sign it...*/ - mark_packet_signed(outbuf); - - /* I wonder what BSRSPYL stands for - but this is what MS - actually sends! */ - memcpy(&outbuf[smb_ss_field], "BSRSPYL ", 8); - return; + return true; } -/*********************************************************** - SMB signing - TEMP implementation - check a MAC sent by server. -************************************************************/ - -static bool temp_check_incoming_message(const char *inbuf, - struct smb_sign_info *si, bool foo) +bool cli_temp_set_signing(struct cli_state *cli) { - return True; + return smb_signing_set_bsrspyl(cli->signing_state); } -/*********************************************************** - SMB signing - TEMP implementation - free signing context -************************************************************/ - -static void temp_free_signing_context(struct smb_sign_info *si) +void cli_calculate_sign_mac(struct cli_state *cli, char *buf, uint32_t *seqnum) { - return; + *seqnum = smb_signing_next_seqnum(cli->signing_state, false); + smb_signing_sign_pdu(cli->signing_state, (uint8_t *)buf, *seqnum); } -/*********************************************************** - SMB signing - NULL implementation - setup the MAC key. -************************************************************/ - -bool cli_null_set_signing(struct cli_state *cli) +bool cli_check_sign_mac(struct cli_state *cli, const char *buf, uint32_t seqnum) { - return null_set_signing(&cli->sign_info); -} + bool ok; -/*********************************************************** - SMB signing - temp implementation - setup the MAC key. -************************************************************/ + ok = smb_signing_check_pdu(cli->signing_state, + (const uint8_t *)buf, + seqnum); -bool cli_temp_set_signing(struct cli_state *cli) -{ - if (!cli_set_smb_signing_common(cli)) { - return False; + if (!ok) { + return false; } - cli->sign_info.signing_context = NULL; - - cli->sign_info.sign_outgoing_message = temp_sign_outgoing_message; - cli->sign_info.check_incoming_message = temp_check_incoming_message; - cli->sign_info.free_signing_context = temp_free_signing_context; - - return True; -} - -void cli_free_signing_context(struct cli_state *cli) -{ - free_signing_context(&cli->sign_info); + return true; } -/** - * Sign a packet with the current mechanism - */ - -void cli_calculate_sign_mac(struct cli_state *cli, char *buf) +void cli_set_signing_negotiated(struct cli_state *cli) { - cli->sign_info.sign_outgoing_message(buf, &cli->sign_info); + smb_signing_set_negotiated(cli->signing_state); } -/** - * Check a packet with the current mechanism - * @return False if we had an established signing connection - * which had a bad checksum, True otherwise. - */ - -bool cli_check_sign_mac(struct cli_state *cli, char *buf) -{ - if (!cli->sign_info.check_incoming_message(buf, &cli->sign_info, True)) { - free_signing_context(&cli->sign_info); - return False; - } - return True; -} - -/*********************************************************** - Enter trans/trans2/nttrans state. -************************************************************/ - -bool client_set_trans_sign_state_on(struct cli_state *cli, uint16 mid) +bool client_is_signing_on(struct cli_state *cli) { - struct smb_sign_info *si = &cli->sign_info; - struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context; - - if (!si->doing_signing) { - return True; - } - - if (!data) { - return False; - } - - if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, False)) { - return False; - } - - return True; + return smb_signing_is_active(cli->signing_state); } -/*********************************************************** - Leave trans/trans2/nttrans state. -************************************************************/ - -bool client_set_trans_sign_state_off(struct cli_state *cli, uint16 mid) +bool client_is_signing_allowed(struct cli_state *cli) { - uint32 reply_seq_num; - struct smb_sign_info *si = &cli->sign_info; - struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context; - - if (!si->doing_signing) { - return True; - } - - if (!data) { - return False; - } - - if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, True)) { - return False; - } - - /* Now delete the stored mid entry. */ - if (!get_sequence_for_reply(&data->outstanding_packet_list, mid, &reply_seq_num)) { - return False; - } - - return True; + return smb_signing_is_allowed(cli->signing_state); } -/*********************************************************** - Is client signing on ? -************************************************************/ - -bool client_is_signing_on(struct cli_state *cli) +bool client_is_signing_mandatory(struct cli_state *cli) { - struct smb_sign_info *si = &cli->sign_info; - return si->doing_signing; + return smb_signing_is_mandatory(cli->signing_state); } -- cgit