/* packet-btmesh.c * Routines for Bluetooth mesh dissection * * Copyright 2017, Anders Broman * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * 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 2 * 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, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "config.h" #include #include #include #include #include #include void proto_register_btmesh(void); gint net_mic_size_chosen = 1; static int proto_btmesh = -1; /*------------------------------------- * UAT for BT Mesh *------------------------------------- */ static uat_t * btmesh_uat = NULL; static guint num_btmesh_uat = 0; /* UAT entry structure. */ typedef struct { gchar *network_key_string; guint8 *network_key; gint network_key_length; gchar *ivindex_string; gint ivindex_string_length; guint8 *ivindex; guint8 *privacykey; guint8 *encryptionkey; guint8 nid; } uat_btmesh_record_t; static uat_btmesh_record_t *uat_btmesh_records = NULL; static int hf_btmesh_ivi = -1; static int hf_btmesh_nid = -1; static int hf_btmesh_obfuscated = -1; static int hf_btmesh_encrypted = -1; static int hf_btmesh_netmic = -1; static int hf_btmesh_ctl = -1; static int hf_btmesh_ttl = -1; static int hf_btmesh_seq = -1; static int hf_btmesh_src = -1; static int hf_btmesh_dst = -1; static int hf_btmesh_transp_pdu = -1; static int hf_btmesh_cntr_seg = -1; static int hf_btmesh_acc_seg = -1; static int hf_btmesh_cntr_opcode = -1; static int hf_btmesh_acc_akf = -1; static int hf_btmesh_acc_aid = -1; static int hf_btmesh_obo = -1; static int hf_btmesh_seqzero = -1; static int hf_btmesh_rfu = -1; static int hf_btmesh_blockack = -1; static int hf_btmesh_criteria_rfu = -1; static int hf_btmesh_padding = -1; static int hf_btmesh_fsn = -1; static int hf_btmesh_criteria_rssifactor = -1; static int hf_btmesh_criteria_receivewindowfactor = -1; static int hf_btmesh_criteria_minqueuesizelog = -1; static int hf_btmesh_receivedelay = -1; static int hf_btmesh_polltimeout = -1; static int hf_btmesh_previousaddress = -1; static int hf_btmesh_numelements = -1; static int hf_btmesh_lpncounter = -1; static int hf_btmesh_receivewindow = -1; static int hf_btmesh_queuesize = -1; static int hf_btmesh_subscriptionlistsize = -1; static int hf_btmesh_rssi = -1; static int hf_btmesh_friendcounter = -1; static int hf_btmesh_lpnaddress = -1; static int hf_btmesh_transactionnumber = -1; static int ett_btmesh = -1; static int ett_btmesh_net_pdu = -1; static int ett_btmesh_transp_pdu = -1; static int ett_btmesh_transp_ctrl_msg = -1; static expert_field ei_btmesh_not_decoded_yet = EI_INIT; static const value_string btmesh_ctl_vals[] = { { 0, "Access Message" }, { 1, "Control Message" }, { 0, NULL } }; static const value_string btmesh_ctrl_seg_vals[] = { { 0, "Unsegmented Control Message" }, { 1, "Segmented Control Message" }, { 0, NULL } }; static const value_string btmesh_acc_seg_vals[] = { { 0, "Unsegmented Access Message" }, { 1, "Segmented Access Message" }, { 0, NULL } }; static const value_string btmesh_acc_akf_vals[] = { { 0, "Device key" }, { 1, "Application key" }, { 0, NULL } }; static const value_string btmesh_ctrl_opcode_vals[] = { { 0x0, "Segment Acknowledgment" }, /* Reserved for lower transport layer */ { 0x1, "Friend Poll" }, { 0x2, "Friend Update" }, { 0x3, "Friend Request" }, { 0x4, "Friend Offer" }, { 0x5, "Friend Clear" }, { 0x6, "Friend Clear Confirm" }, { 0x7, "Friend Subscription List Add" }, { 0x8, "Friend Subscription List Remove" }, { 0x9, "Friend Subscription List Confirm" }, { 0xa, "Heartbeat" }, { 0, NULL } }; static const true_false_string btmesh_obo = { "Friend node that is acknowledging this message on behalf of a Low Power node", "Node that is directly addressed by the received message" }; static const value_string btmesh_criteria_rssifactor_vals[] = { { 0x0, "1" }, { 0x1, "1.5" }, { 0x2, "2" }, { 0x3, "2.5" }, { 0, NULL } }; static const value_string btmesh_criteria_receivewindowfactor_vals[] = { { 0x0, "1" }, { 0x1, "1.5" }, { 0x2, "2" }, { 0x3, "2.5" }, { 0, NULL } }; static const value_string btmesh_criteria_minqueuesizelog_vals[] = { { 0x0, "Prohibited" }, { 0x1, "N = 2" }, { 0x2, "N = 4" }, { 0x3, "N = 8" }, { 0x4, "N = 16" }, { 0x5, "N = 32" }, { 0x6, "N = 64" }, { 0x7, "N = 128" }, { 0, NULL } }; static gint dissect_btmesh_msg_no_decrypt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_item *item; proto_tree *sub_tree; int offset = 0; col_set_str(pinfo->cinfo, COL_PROTOCOL, "BT Mesh"); col_clear(pinfo->cinfo, COL_INFO); item = proto_tree_add_item(tree, proto_btmesh, tvb, offset, -1, ENC_NA); sub_tree = proto_item_add_subtree(item, ett_btmesh); /* First byte in plaintext */ /* IVI 1 bit Least significant bit of IV Index */ proto_tree_add_item(sub_tree, hf_btmesh_ivi, tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(sub_tree, hf_btmesh_nid, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(sub_tree, hf_btmesh_obfuscated, tvb, offset, 6, ENC_NA); offset += 6; proto_tree_add_item(sub_tree, hf_btmesh_encrypted, tvb, offset, -1, ENC_NA); return tvb_reported_length(tvb); } /* A BT Mesh dissector is not realy useful without decryption as all packets are encrypted. Just leave a stub dissector outside of*/ #if GCRYPT_VERSION_NUMBER >= 0x010600 /* 1.6.0 */ /* BT Mesh s1 function */ static gboolean s1(guint8 *m, size_t mlen, guint8 *salt) { gcry_mac_hd_t mac_hd; int gcrypt_err; size_t read_digest_length = 16; guint8 zero[16] = { 0 }; /* Open gcrypt handle */ gcrypt_err = gcry_mac_open(&mac_hd, GCRY_MAC_CMAC_AES, 0, NULL); if (gcrypt_err != 0) { return FALSE; } /* Set the key */ gcrypt_err = gcry_mac_setkey(mac_hd, &zero, 16); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } gcrypt_err = gcry_mac_write(mac_hd, m, mlen); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return 0; } /* Read out the digest */ gcrypt_err = gcry_mac_read(mac_hd, salt, &read_digest_length); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return 0; } /* Now close the mac handle */ gcry_mac_close(mac_hd); return TRUE; } /* BT Mesh K2 function * Allow plen up to 9 char * * The key (T) is computed as follows: * T = AES-CMACSALT (N) * SALT is the 128-bit value computed as follows * SALT = s1("smk2") * The output of the key generation function k2 is as follows: * T0 = empty string (zero length) * T1 = AES-CMACT (T0 || P || 0x01) * T2 = AES-CMACT (T1 || P || 0x02) * T3 = AES-CMACT (T2 || P || 0x03) * k2(N, P) = (T1 || T2 || T3) mod 2(pow)263 */ static gboolean k2(uat_btmesh_record_t * net_key_set, guint8 *p, size_t plen) { gcry_mac_hd_t mac_hd; int gcrypt_err; guint8 smk2[4] = { 's', 'm', 'k', '2' }; size_t mlen = 4; guint8 salt[16]; guint8 t[16]; guint8 t1[16]; guint8 p_t1[9 + 1]; guint8 p_t2[16 + 9 + 1]; guint8 p_t3[16 + 9 + 1]; size_t read_digest_length = 16; if (plen > 8) { return FALSE; } /* SALT = s1("smk2") */ if (s1(smk2, mlen, salt) == FALSE) { return FALSE; } /* T = AES-CMAC_SALT(N) */ /* Open gcrypt handle */ gcrypt_err = gcry_mac_open(&mac_hd, GCRY_MAC_CMAC_AES, 0, NULL); if (gcrypt_err != 0) { return FALSE; } /* Set the key */ gcrypt_err = gcry_mac_setkey(mac_hd, &salt, 16); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } gcrypt_err = gcry_mac_write(mac_hd, net_key_set->network_key, 16); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } /* Read out the digest */ gcrypt_err = gcry_mac_read(mac_hd, t, &read_digest_length); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } /* Now close the mac handle */ gcry_mac_close(mac_hd); // T0 = empty string (zero length) // T1 = AES-CMAC_T(T0 || P || 0x01) memcpy(p_t1, p, plen); p_t1[plen] = 0x01; /* Open gcrypt handle */ gcrypt_err = gcry_mac_open(&mac_hd, GCRY_MAC_CMAC_AES, 0, NULL); if (gcrypt_err != 0) { return FALSE; } /* Set the key */ gcrypt_err = gcry_mac_setkey(mac_hd, &t, 16); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } gcrypt_err = gcry_mac_write(mac_hd, &p_t1, plen + 1); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } /* Read out the digest */ gcrypt_err = gcry_mac_read(mac_hd, t1, &read_digest_length); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } net_key_set->nid = (t1[15] & 0x7f); /* T2 = AES-CMAC_T(T1 || P || 0x02) * (EncryptionKey) */ memcpy(p_t2, t1, 16); memcpy(&p_t2[16], p, plen); p_t2[16 + plen] = 0x02; /* Open gcrypt handle */ gcrypt_err = gcry_mac_open(&mac_hd, GCRY_MAC_CMAC_AES, 0, NULL); if (gcrypt_err != 0) { return FALSE; } /* Set the key */ gcrypt_err = gcry_mac_setkey(mac_hd, &t, 16); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } gcrypt_err = gcry_mac_write(mac_hd, &p_t2, 16 + plen + 1); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } /* Read out the digest */ gcrypt_err = gcry_mac_read(mac_hd, net_key_set->encryptionkey, &read_digest_length); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } /* T3 = AES-CMAC_T(T2 || P || 0x03) */ /* PrivacyKey */ memcpy(p_t3, net_key_set->encryptionkey, 16); memcpy(&p_t3[16], p, plen); p_t3[16 + plen] = 0x03; /* Open gcrypt handle */ gcrypt_err = gcry_mac_open(&mac_hd, GCRY_MAC_CMAC_AES, 0, NULL); if (gcrypt_err != 0) { return FALSE; } /* Set the key */ gcrypt_err = gcry_mac_setkey(mac_hd, t, 16); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } gcrypt_err = gcry_mac_write(mac_hd, p_t3, 16 + plen + 1); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } /* Read out the digest */ gcrypt_err = gcry_mac_read(mac_hd, net_key_set->privacykey, &read_digest_length); if (gcrypt_err != 0) { gcry_mac_close(mac_hd); return FALSE; } return TRUE; } static gboolean create_master_security_keys(uat_btmesh_record_t * net_key_set) { guint8 p[1] = { 0 }; size_t plen = 1; k2(net_key_set, p, plen); return TRUE; } static tvbuff_t * btmesh_deobfuscate(tvbuff_t *tvb, packet_info *pinfo, int offset _U_, uat_btmesh_record_t *net_key_set) { tvbuff_t *de_obf_tvb = NULL; /* Decode ObfuscatedData * Privacy Random = (EncDST || EncTransportPDU || NetMIC)[0-6] * PECB = e ((PrivacyKey, 0x0000000000 || IV Index || Privacy Random) * (CTL || TTL || SEQ || SRC) = ObfuscatedData */ guint8 in[16]; /* 0x0000000000 || IV Index || Privacy Random */ gcry_cipher_hd_t cipher_hd; guint8 pecb[16]; guint8 *plaintextnetworkheader = (guint8 *)wmem_alloc(pinfo->pool, 6); int i; memset(in, 0x00, 5); in[5] = net_key_set->ivindex[0]; in[6] = net_key_set->ivindex[1]; in[7] = net_key_set->ivindex[2]; in[8] = net_key_set->ivindex[3]; /* Privacy random */ tvb_memcpy(tvb, (guint8 *)&in+9, 7, 7); if (gcry_cipher_open(&cipher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_ECB, 0)) { return NULL; } if (gcry_cipher_setkey(cipher_hd, net_key_set->privacykey, 16)) { gcry_cipher_close(cipher_hd); return NULL; } /* Decrypt */ if (gcry_cipher_encrypt(cipher_hd, &pecb, 16, &in, 16)) { gcry_cipher_close(cipher_hd); return NULL; } /* Now close the mac handle */ gcry_cipher_close(cipher_hd); for ( i = 0; i<6; i++) { plaintextnetworkheader[i] = tvb_get_guint8(tvb,i+1) ^ pecb[i]; } de_obf_tvb = tvb_new_child_real_data(tvb, plaintextnetworkheader, 6, 6); add_new_data_source(pinfo, de_obf_tvb, "Deobfuscated data"); return de_obf_tvb; } static void dissect_btmesh_transport_constrol_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, guint32 opcode) { proto_tree *sub_tree; sub_tree = proto_tree_add_subtree_format(tree, tvb, offset, -1, ett_btmesh_transp_ctrl_msg, NULL, "Transport Control Message %s", val_to_str_const(opcode, btmesh_ctrl_opcode_vals, "Unknown")); switch (opcode) { case 1: /* 3.6.5.1 Friend Poll */ /* Padding 7 bits */ proto_tree_add_item(sub_tree, hf_btmesh_padding, tvb, offset, 1, ENC_BIG_ENDIAN); /* FSN 1 bit*/ proto_tree_add_item(sub_tree, hf_btmesh_fsn, tvb, offset, 1, ENC_BIG_ENDIAN); break; case 2: /* 3.6.5.2 Friend Update */ /* Flags 1 octet */ /* IV Index 4 octets*/ /* MD 1 octet */ proto_tree_add_expert(sub_tree, pinfo, &ei_btmesh_not_decoded_yet, tvb, offset, -1); break; case 3: /* Friend Request */ /* Criteria 1 octet */ /* RFU 1 bit */ proto_tree_add_item(sub_tree, hf_btmesh_criteria_rfu, tvb, offset, 1, ENC_BIG_ENDIAN); /* RSSIFactor 2 bits */ proto_tree_add_item(sub_tree, hf_btmesh_criteria_rssifactor, tvb, offset, 1, ENC_BIG_ENDIAN); /* ReceiveWindowFactor 2 bits */ proto_tree_add_item(sub_tree, hf_btmesh_criteria_receivewindowfactor, tvb, offset, 1, ENC_BIG_ENDIAN); /* MinQueueSizeLog 3 bits */ proto_tree_add_item(sub_tree, hf_btmesh_criteria_minqueuesizelog, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* ReceiveDelay 1 octet */ proto_tree_add_item(sub_tree, hf_btmesh_receivedelay, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* PollTimeout 3 octets */ proto_tree_add_item(sub_tree, hf_btmesh_polltimeout, tvb, offset, 3, ENC_BIG_ENDIAN); offset+=3; /* PreviousAddress 2 octets */ proto_tree_add_item(sub_tree, hf_btmesh_previousaddress, tvb, offset, 2, ENC_BIG_ENDIAN); offset+=2; /* NumElements 1 octets */ proto_tree_add_item(sub_tree, hf_btmesh_numelements, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1; /* LPNCounter 1 octets */ proto_tree_add_item(sub_tree, hf_btmesh_lpncounter, tvb, offset, 1, ENC_BIG_ENDIAN); break; case 4: /* 3.6.5.4 Friend Offer */ /* ReceiveWindow 1 octet */ proto_tree_add_item(sub_tree, hf_btmesh_receivewindow, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* QueueSize 1 octet */ proto_tree_add_item(sub_tree, hf_btmesh_queuesize, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* SubscriptionListSize 1 octet */ proto_tree_add_item(sub_tree, hf_btmesh_subscriptionlistsize, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* RSSI 1 octet */ proto_tree_add_item(sub_tree, hf_btmesh_rssi, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* FriendCounter 2 octets */ proto_tree_add_item(sub_tree, hf_btmesh_friendcounter, tvb, offset, 1, ENC_BIG_ENDIAN); break; case 5: /* 3.6.5.5 Friend Clear */ /* LPNAddress 2 octets */ proto_tree_add_item(sub_tree, hf_btmesh_lpnaddress, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 2; /* LPNCounter 2 octets */ proto_tree_add_item(sub_tree, hf_btmesh_lpncounter, tvb, offset, 1, ENC_BIG_ENDIAN); break; case 6: /* 3.6.5.6 Friend Clear Confirm */ /* LPNAddress 2 octets */ proto_tree_add_item(sub_tree, hf_btmesh_lpnaddress, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 2; /* LPNCounter 2 octets */ proto_tree_add_item(sub_tree, hf_btmesh_lpncounter, tvb, offset, 1, ENC_BIG_ENDIAN); break; case 7: /* 3.6.5.7 Friend Subscription List Add */ /* TransactionNumber 1 octet */ proto_tree_add_item(sub_tree, hf_btmesh_transactionnumber, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* AddressList 2 * N */ proto_tree_add_expert(sub_tree, pinfo, &ei_btmesh_not_decoded_yet, tvb, offset, -1); break; case 8: /* 3.6.5.8 Friend Subscription List Remove */ proto_tree_add_item(sub_tree, hf_btmesh_transactionnumber, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* AddressList 2 * N */ proto_tree_add_expert(sub_tree, pinfo, &ei_btmesh_not_decoded_yet, tvb, offset, -1); break; case 9: /* 3.6.5.9 Friend Subscription List Confirm */ proto_tree_add_item(sub_tree, hf_btmesh_transactionnumber, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; break; case 10: /* 3.6.5.10 Heartbeat */ default: proto_tree_add_expert(sub_tree, pinfo, &ei_btmesh_not_decoded_yet, tvb, offset, -1); break; } } static void dissect_btmesh_transport_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean cntrl) { proto_tree *sub_tree; int offset = 0; guint32 value, opcode; /* We receive the full decrypted buffer including DST, skip to opcode */ offset += 2; sub_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_btmesh_transp_pdu, NULL, "Lower Transport PDU"); if (cntrl) { proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_cntr_seg, tvb, offset, 1, ENC_BIG_ENDIAN, &value); if (value) { /* Segmented */ } else { proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_cntr_opcode, tvb, offset, 1, ENC_BIG_ENDIAN, &opcode); offset++; col_append_fstr(pinfo->cinfo, COL_INFO, "%s", val_to_str_const(opcode, btmesh_ctrl_opcode_vals, "Unknown")); if (opcode == 0) { /* OBO 1 */ proto_tree_add_item(sub_tree, hf_btmesh_obo, tvb, offset, 2, ENC_BIG_ENDIAN); /* SeqZero 13 */ proto_tree_add_item(sub_tree, hf_btmesh_seqzero, tvb, offset, 2, ENC_BIG_ENDIAN); /* RFU 2 */ proto_tree_add_item(sub_tree, hf_btmesh_rfu, tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; /* BlockAck 32 */ proto_tree_add_item(sub_tree, hf_btmesh_blockack, tvb, offset, 4, ENC_BIG_ENDIAN); return; } dissect_btmesh_transport_constrol_message(tvb, pinfo, tree, offset, opcode); } } else { guint32 seg, afk, aid; /* Access message */ proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_acc_seg, tvb, offset, 1, ENC_BIG_ENDIAN, &seg); /* AKF 1 Application Key Flag */ proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_acc_akf, tvb, offset, 1, ENC_BIG_ENDIAN, &afk); /* AID 6 Application key identifier */ proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_acc_aid, tvb, offset, 1, ENC_BIG_ENDIAN, &aid); offset++; if (seg) { /* Segmented */ /* SZMIC 1 Size of TransMIC */ /* SeqZero 13 Least significant bits of SeqAuth */ /* SegO 5 Segment Offset number */ /* SegN 5 Last Segment number */ /* Segment m 8 to 96 Segment m of the Upper Transport Access PDU */ } else { } } } static gint dissect_btmesh_msg(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_item *item; proto_tree *netw_tree, *sub_tree; int offset = 0, enc_offset; guint i; guint8 nid; gboolean found; guint32 net_mic_size, seq, src; int enc_data_len; tvbuff_t *de_obf_tvb; guint8 networknonce[13]; gcry_cipher_hd_t cipher_hd; /*gcry_error_t cry_error;*/ gboolean cry_error; guint64 ccm_lengths[3]; tvbuff_t *de_cry_tvb; int decry_off; guint8 *decrypted_data; uat_btmesh_record_t *record; nid = tvb_get_guint8(tvb, offset) & 0x7f; found = FALSE; /* Get the next record to try */ for (i = 0; i < num_btmesh_uat; i++) { record = &uat_btmesh_records[i]; if (nid == record->nid) { found = TRUE; break; } } if (!found) { /* No matching UAT records found */ return dissect_btmesh_msg_no_decrypt(tvb, pinfo, tree, data); } col_set_str(pinfo->cinfo, COL_PROTOCOL, "BT Mesh"); col_clear(pinfo->cinfo, COL_INFO); item = proto_tree_add_item(tree, proto_btmesh, tvb, offset, -1, ENC_NA); netw_tree = proto_item_add_subtree(item, ett_btmesh); sub_tree = proto_tree_add_subtree(netw_tree, tvb, offset, -1, ett_btmesh_net_pdu, NULL, "Network PDU"); /* Check lengt >= , if not error packet */ /* First byte in plaintext */ /* IVI 1 bit Least significant bit of IV Index */ proto_tree_add_item(sub_tree, hf_btmesh_ivi, tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(sub_tree, hf_btmesh_nid, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; de_obf_tvb = btmesh_deobfuscate(tvb, pinfo, offset, record); if (de_obf_tvb) { gboolean cntrl; /* Start setting network nounce.*/ networknonce[0] = 0; /* Nonce Type */ /* CTL 1 bit Network Control*/ proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_ctl, de_obf_tvb, 0, 1, ENC_BIG_ENDIAN, &net_mic_size); /* 32 or 64 bits ( 0 or 1 )*/ cntrl = net_mic_size; net_mic_size = (net_mic_size + 1) * 4; /* The TTL field is a 7-bit field */ proto_tree_add_item(sub_tree, hf_btmesh_ttl, de_obf_tvb, 0, 1, ENC_BIG_ENDIAN); networknonce[1] = tvb_get_guint8(de_obf_tvb,0);/* CTL and TTL */ /* SEQ field is a 24-bit integer */ proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_seq, de_obf_tvb, 1, 3, ENC_BIG_ENDIAN, &seq); networknonce[2] = seq >> 16; networknonce[3] = seq >> 8; networknonce[4] = seq; /* SRC field is a 16-bit value */ proto_tree_add_item_ret_uint(sub_tree, hf_btmesh_src, de_obf_tvb, 4, 2, ENC_BIG_ENDIAN, &src); offset += 6; networknonce[5] = src >> 8; networknonce[6] = src; networknonce[7] = 0x00; /*Pad*/ networknonce[8] = 0x00; /*Pad*/ networknonce[9] = record->ivindex[0]; networknonce[10] = record->ivindex[1]; networknonce[11] = record->ivindex[2]; networknonce[12] = record->ivindex[3]; enc_data_len = tvb_reported_length(tvb) - 1 - 6 - net_mic_size; enc_offset = offset; /* Decrypt packet EXPERIMENTAL CODE */ if (gcry_cipher_open(&cipher_hd, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CCM, 0)) { return offset; } cry_error = gcry_cipher_setkey(cipher_hd, record->encryptionkey, 16); if (cry_error) { g_warning("gcry_cipher_setkey failed"); gcry_cipher_close(cipher_hd); return offset; } /* Load nonce */ cry_error = gcry_cipher_setiv(cipher_hd, &networknonce, 13); if (cry_error) { g_warning("gcry_cipher_setiv failed"); gcry_cipher_close(cipher_hd); return offset; } /* */ ccm_lengths[0] = enc_data_len; ccm_lengths[1] = 0; /* aad */ ccm_lengths[2] = net_mic_size; /* icv NOT SURE ABOUT THIS ONE */ cry_error = gcry_cipher_ctl(cipher_hd, GCRYCTL_SET_CCM_LENGTHS, ccm_lengths, sizeof(ccm_lengths)); if (cry_error) { g_warning("gcry_cipher_ctl failed %s enc_data_len %u", gcry_strerror(cry_error), enc_data_len); gcry_cipher_close(cipher_hd); return offset; } decrypted_data = (guint8 *)wmem_alloc(pinfo->pool, enc_data_len); /* Decrypt */ cry_error = gcry_cipher_decrypt(cipher_hd, decrypted_data, enc_data_len, tvb_get_ptr(tvb, enc_offset, enc_data_len), enc_data_len); if (cry_error) { g_warning("gcry_cipher_decrypt failed %s", gcry_strerror(cry_error)); gcry_cipher_close(cipher_hd); return offset; } /* Now close the cypher handle */ gcry_cipher_close(cipher_hd); de_cry_tvb = tvb_new_child_real_data(tvb, decrypted_data, enc_data_len, enc_data_len); add_new_data_source(pinfo, de_cry_tvb, "Decrypted data"); decry_off = 0; proto_tree_add_item(sub_tree, hf_btmesh_dst, de_cry_tvb, decry_off, 2, ENC_BIG_ENDIAN); decry_off += 2; /* TransportPDU */ proto_tree_add_item(sub_tree, hf_btmesh_transp_pdu, de_cry_tvb, decry_off, enc_data_len-2, ENC_NA); offset += enc_data_len; proto_tree_add_item(sub_tree, hf_btmesh_netmic, tvb, offset, net_mic_size, ENC_BIG_ENDIAN); offset += net_mic_size; if (de_cry_tvb) { dissect_btmesh_transport_pdu(de_cry_tvb, pinfo, netw_tree, cntrl); } } else { proto_tree_add_item(sub_tree, hf_btmesh_obfuscated, tvb, offset, 6, ENC_NA); offset += 6; proto_tree_add_item(sub_tree, hf_btmesh_encrypted, tvb, offset, -1, ENC_NA); offset = tvb_reported_length(tvb); } return offset; } #else /* GCRYPT_VERSION_NUMBER >= 0x010600 */ static gboolean create_master_security_keys(uat_btmesh_record_t * net_key_set _U_) { return TRUE; } /* Stub dissector if decryption not available on build system */ static gint dissect_btmesh_msg(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) { return dissect_btmesh_msg_no_decrypt(tvb, pinfo, tree, data); } #endif /* GCRYPT_VERSION_NUMBER >= 0x010600 */ static gint compute_ascii_key(guchar **ascii_key, const gchar *key) { guint key_len = 0, raw_key_len; gint hex_digit; guchar key_byte; guint i, j; if (key != NULL) { raw_key_len = (guint)strlen(key); if ((raw_key_len > 2) && (key[0] == '0') && ((key[1] == 'x') || (key[1] == 'X'))) { /* * Key begins with "0x" or "0X"; skip that and treat the rest * as a sequence of hex digits. */ i = 2; /* first character after "0[Xx]" */ j = 0; if (raw_key_len % 2 == 1) { /* * Key has an odd number of characters; we act as if the * first character had a 0 in front of it, making the * number of characters even. */ key_len = (raw_key_len - 2) / 2 + 1; *ascii_key = (gchar *)g_malloc((key_len + 1) * sizeof(gchar)); hex_digit = g_ascii_xdigit_value(key[i]); i++; if (hex_digit == -1) { g_free(*ascii_key); *ascii_key = NULL; return -1; /* not a valid hex digit */ } (*ascii_key)[j] = (guchar)hex_digit; j++; } else { /* * Key has an even number of characters, so we treat each * pair of hex digits as a single byte value. */ key_len = (raw_key_len - 2) / 2; *ascii_key = (gchar *)g_malloc((key_len + 1) * sizeof(gchar)); } while (i < (raw_key_len - 1)) { hex_digit = g_ascii_xdigit_value(key[i]); i++; if (hex_digit == -1) { g_free(*ascii_key); *ascii_key = NULL; return -1; /* not a valid hex digit */ } key_byte = ((guchar)hex_digit) << 4; hex_digit = g_ascii_xdigit_value(key[i]); i++; if (hex_digit == -1) { g_free(*ascii_key); *ascii_key = NULL; return -1; /* not a valid hex digit */ } key_byte |= (guchar)hex_digit; (*ascii_key)[j] = key_byte; j++; } (*ascii_key)[j] = '\0'; } else if ((raw_key_len == 2) && (key[0] == '0') && ((key[1] == 'x') || (key[1] == 'X'))) { return 0; } else { key_len = raw_key_len; *ascii_key = g_strdup(key); } } return key_len; } static gboolean uat_btmesh_record_update_cb(void *r, char **err _U_) { uat_btmesh_record_t *rec = (uat_btmesh_record_t *)r; /* Compute keys & lengths once and for all */ if (rec->network_key_string) { rec->network_key_length = compute_ascii_key(&rec->network_key, rec->network_key_string); rec->encryptionkey = (guint8 *)g_malloc(16 * sizeof(guint8)); rec->privacykey = (guint8 *)g_malloc(16 * sizeof(guint8)); create_master_security_keys(rec); } else { rec->network_key_length = 0; rec->network_key = NULL; } if (rec->ivindex_string) { rec-> ivindex_string_length = compute_ascii_key(&rec->ivindex, rec->ivindex_string); } return TRUE; } static void * uat_btmesh_record_copy_cb(void *n, const void *o, size_t siz _U_) { uat_btmesh_record_t *new_rec = (uat_btmesh_record_t *)n; const uat_btmesh_record_t* old_rec = (const uat_btmesh_record_t *)o; /* Copy UAT fields */ new_rec->network_key_string = g_strdup(old_rec->network_key_string); new_rec->ivindex_string = g_strdup(old_rec->ivindex_string); /* Parse keys as in an update */ uat_btmesh_record_update_cb(new_rec, NULL); return new_rec; } static void uat_btmesh_record_free_cb(void *r) { uat_btmesh_record_t *rec = (uat_btmesh_record_t *)r; g_free(rec->network_key_string); g_free(rec->network_key); } UAT_CSTRING_CB_DEF(uat_btmesh_records, network_key_string, uat_btmesh_record_t) UAT_CSTRING_CB_DEF(uat_btmesh_records, ivindex_string, uat_btmesh_record_t) void proto_register_btmesh(void) { static hf_register_info hf[] = { { &hf_btmesh_ivi, { "IVI", "btmesh.ivi", FT_UINT8, BASE_DEC, NULL, 0x80, NULL, HFILL } }, { &hf_btmesh_nid, { "NID", "btmesh.nid", FT_UINT8, BASE_DEC, NULL, 0x7f, NULL, HFILL } }, { &hf_btmesh_obfuscated, { "Obfuscated", "btmesh.obfuscated", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_encrypted, { "Encrypted data and NetMIC", "btmesh.encrypted", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_netmic, { "NetMIC", "btmesh.netmic", FT_UINT64, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_ctl, { "CTL", "btmesh.ctl", FT_UINT8, BASE_DEC, VALS(btmesh_ctl_vals), 0x80, NULL, HFILL } }, { &hf_btmesh_ttl, { "TTL", "btmesh.ttl", FT_UINT8, BASE_DEC, NULL, 0x7f, NULL, HFILL } }, { &hf_btmesh_seq, { "SEQ", "btmesh.seq", FT_UINT24, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_src, { "SRC", "btmesh.src", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_dst, { "DST", "btmesh.dst", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_transp_pdu, { "TransportPDU", "btmesh.transp_pdu", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_cntr_seg, { "SEG", "btmesh.cntr.seg", FT_UINT8, BASE_DEC, VALS(btmesh_ctrl_seg_vals), 0x80, NULL, HFILL } }, { &hf_btmesh_acc_seg, { "SEG", "btmesh.acc.seg", FT_UINT8, BASE_DEC, VALS(btmesh_acc_seg_vals), 0x80, NULL, HFILL } }, { &hf_btmesh_cntr_opcode, { "Opcode", "btmesh.cntr.opcode", FT_UINT8, BASE_DEC, VALS(btmesh_ctrl_opcode_vals), 0x7f, NULL, HFILL } }, { &hf_btmesh_acc_akf, { "AKF", "btmesh.acc.akf", FT_UINT8, BASE_DEC, VALS(btmesh_acc_akf_vals), 0x40, NULL, HFILL } }, { &hf_btmesh_acc_aid, { "AID", "btmesh.acc.aid", FT_UINT8, BASE_DEC, NULL, 0x3f, NULL, HFILL } }, { &hf_btmesh_obo, { "OBO", "btmesh.obo", FT_BOOLEAN, 16, TFS(&btmesh_obo), 0x8000, NULL, HFILL } }, { &hf_btmesh_seqzero, { "SeqZero", "btmesh.seqzero", FT_UINT16, BASE_DEC, NULL, 0x7ffc, NULL, HFILL } }, { &hf_btmesh_rfu, { "Reserved for Future Use", "btmesh.rfu", FT_UINT16, BASE_DEC, NULL, 0x0003, NULL, HFILL } }, { &hf_btmesh_blockack, { "BlockAck", "btmesh.blockack", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_criteria_rfu, { "RFU", "btmesh.criteria.rfu", FT_UINT8, BASE_DEC, NULL, 0x80, NULL, HFILL } }, { &hf_btmesh_padding, { "Padding", "btmesh.padding", FT_UINT8, BASE_DEC, NULL, 0xfe, NULL, HFILL } }, { &hf_btmesh_fsn, { "Friend Sequence Number(FSN)", "btmesh.fsn", FT_UINT8, BASE_DEC, NULL, 0x01, NULL, HFILL } }, { &hf_btmesh_criteria_rssifactor, { "RSSIFactor", "btmesh.criteria.rssifactor", FT_UINT8, BASE_DEC, VALS(btmesh_criteria_rssifactor_vals), 0x60, NULL, HFILL } }, { &hf_btmesh_criteria_receivewindowfactor, { "ReceiveWindowFactor", "btmesh.criteria.receivewindowfactor", FT_UINT8, BASE_DEC, VALS(btmesh_criteria_receivewindowfactor_vals), 0x18, NULL, HFILL } }, { &hf_btmesh_criteria_minqueuesizelog, { "MinQueueSizeLog", "btmesh.criteria.minqueuesizelog", FT_UINT8, BASE_DEC, VALS(btmesh_criteria_minqueuesizelog_vals), 0x07, NULL, HFILL } }, { &hf_btmesh_receivedelay, { "ReceiveDelay", "btmesh.receivedelay", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_polltimeout, { "PollTimeout", "btmesh.polltimeout", FT_UINT24, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_previousaddress, { "PreviousAddress", "btmesh.previousaddress", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_numelements, { "NumElements", "btmesh.numelements", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_lpncounter, { "LPNCounter", "btmesh.lpncounter", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_receivewindow, { "ReceiveWindow", "btmesh.receivewindow", FT_UINT8, BASE_DEC | BASE_UNIT_STRING, &units_milliseconds, 0x0, NULL, HFILL } }, { &hf_btmesh_queuesize, { "QueueSize", "btmesh.queuesize", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_subscriptionlistsize, { "SubscriptionListSize", "btmesh.subscriptionlistsize", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_rssi, { "RSSI", "btmesh.rssi", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_friendcounter, { "FriendCounter", "btmesh.friendcounter", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_lpnaddress, { "LPNAddress", "btmesh.lpnaddress", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_btmesh_transactionnumber, { "TransactionNumber", "btmesh.transactionnumber", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } } }; static gint *ett[] = { &ett_btmesh, &ett_btmesh_net_pdu, &ett_btmesh_transp_pdu, &ett_btmesh_transp_ctrl_msg, }; static ei_register_info ei[] = { { &ei_btmesh_not_decoded_yet,{ "btmesh.not_decoded_yet", PI_PROTOCOL, PI_NOTE, "Not decoded yet", EXPFILL } }, }; expert_module_t* expert_btmesh; module_t *btmesh_module; /* UAT defenitions */ static uat_field_t btmesh_uat_flds[] = { UAT_FLD_CSTRING(uat_btmesh_records, network_key_string, "Network Key", "Network Key"), UAT_FLD_CSTRING(uat_btmesh_records, ivindex_string, "IVindex", "IVindex"), UAT_END_FIELDS }; proto_btmesh = proto_register_protocol("Bluetooth Mesh", "BT Mesh", "btmesh"); proto_register_field_array(proto_btmesh, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_btmesh = expert_register_protocol(proto_btmesh); expert_register_field_array(expert_btmesh, ei, array_length(ei)); btmesh_module = prefs_register_protocol(proto_btmesh, NULL); btmesh_uat = uat_new("BTMesh Network keys", sizeof(uat_btmesh_record_t), /* record size */ "btmesh_nw_keys", /* filename */ TRUE, /* from_profile */ &uat_btmesh_records, /* data_ptr */ &num_btmesh_uat, /* numitems_ptr */ UAT_AFFECTS_DISSECTION, /* affects dissection of packets, but not set of named fields */ NULL, /* help */ uat_btmesh_record_copy_cb, /* copy callback */ uat_btmesh_record_update_cb, /* update callback */ uat_btmesh_record_free_cb, /* free callback */ NULL, /* post update callback */ NULL, /* reset callback */ btmesh_uat_flds); /* UAT field definitions */ prefs_register_uat_preference(btmesh_module, "newtwork_key_table", "Network keys", "Preconfigured Network keys", btmesh_uat); register_dissector("btmesh.msg", dissect_btmesh_msg, proto_btmesh); } /* * Editor modelines * * Local Variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * ex: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */