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Added key derivation function.

pull/70/head
weetmuts 2020-01-28 16:33:02 +01:00
rodzic a6c73e10db
commit d81a573c6c
2 zmienionych plików z 47 dodań i 25 usunięć
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58
src/wmbus.cc
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@ -191,7 +191,7 @@ LIST_OF_MANUFACTURERS
void Telegram::print() {
notice("Received telegram from: %02x%02x%02x%02x\n",
a_field_address[0], a_field_address[1], a_field_address[2], a_field_address[3]);
dll_id[0], dll_id[1], dll_id[2], dll_id[3]);
notice(" manufacturer: (%s) %s\n",
manufacturerFlag(dll_mft).c_str(),
manufacturer(dll_mft).c_str());
@ -207,7 +207,7 @@ void Telegram::printDLL()
dll_c,
dll_mft,
man.c_str(),
a_field_address[0], a_field_address[1], a_field_address[2], a_field_address[3],
dll_id[0], dll_id[1], dll_id[2], dll_id[3],
dll_version,
dll_type,
mediaType(dll_type).c_str());
@ -908,11 +908,15 @@ bool Telegram::parseDLL(vector<uchar>::iterator &pos)
addExplanationAndIncrementPos(pos, 2, "%02x%02x m-field (%02x=%s)", frame[2], frame[3], dll_mft, man.c_str());
dll_a.resize(6);
a_field_address.resize(4);
dll_id.resize(4);
for (int i=0; i<6; ++i)
{
dll_a[i] = *(pos+i);
if (i<4) { a_field_address[i] = *(pos+3-i); }
if (i<4)
{
dll_id_b[i] = *(pos+i);
dll_id[i] = *(pos+3-i);
}
}
strprintf(id, "%02x%02x%02x%02x", *(pos+3), *(pos+2), *(pos+1), *(pos+0));
addExplanationAndIncrementPos(pos, 4, "%02x%02x%02x%02x a-field-addr (%s)",
@ -942,7 +946,7 @@ string Telegram::toStringFromELLSN(int sn)
return info;
}
bool Telegram::parseELL(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
bool Telegram::parseELL(vector<uchar>::iterator &pos)
{
int remaining = distance(pos, frame.end());
if (remaining == 0) return false;
@ -1288,14 +1292,28 @@ bool Telegram::parseTPLConfig(std::vector<uchar>::iterator &pos)
if (tpl_kdf_selection == 1)
{
vector<uchar> key;
vector<uchar> input;
vector<uchar> mac;
mac.resize(16);
// DC C ID 0x07 0x07 0x07 0x07 0x07 0x07 0x07
// Derivation Constant DC = 0x00 = encryption from meter.
// 0x01 = mac from meter.
// 0x10 = encryption from communication partner.
// 0x11 = mac from communication partner.
input.insert(input.end(), 0);
// If there is a tpl_counter, then use it, else use afl_counter.
input.insert(input.end(), afl_counter_b, afl_counter_b+4);
// If there is a tpl_id, then use it, else use ddl_id.
input.insert(input.end(), dll_id_b, dll_id_b+4);
// Pad.
for (int i=0; i<7; ++i) input.insert(input.end(), 0x07);
AES_CMAC(&key[0], &input[0], 16, &mac[0]);
if (meter_keys->confidentiality_key.size() != 16)
{
return false;
}
AES_CMAC(&meter_keys->confidentiality_key[0], &input[0], 16, &mac[0]);
string s = bin2hex(mac);
tpl_generated_key.clear();
tpl_generated_key.insert(tpl_generated_key.end(), mac.begin(), mac.end());
@ -1350,7 +1368,7 @@ bool Telegram::parseLongTPL(std::vector<uchar>::iterator &pos)
bool loadFormatBytesFromSignature(uint16_t format_signature, vector<uchar> *format_bytes);
bool Telegram::potentiallyDecrypt(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
bool Telegram::potentiallyDecrypt(vector<uchar>::iterator &pos)
{
if (tpl_sec_mode == TPLSecurityMode::AES_CBC_IV)
{
@ -1366,6 +1384,7 @@ bool Telegram::potentiallyDecrypt(vector<uchar>::iterator &pos, MeterKeys *meter
}
else if (tpl_sec_mode == TPLSecurityMode::AES_CBC_NO_IV)
{
fprintf(stderr, "BLALSALDLASDÖLAKDLAKDSÖLADS\n");
bool ok = decrypt_TPL_AES_CBC_NO_IV(this, frame, pos, tpl_generated_key);
if (!ok) return false;
// Now the frame from pos and onwards has been decrypted.
@ -1379,12 +1398,12 @@ bool Telegram::potentiallyDecrypt(vector<uchar>::iterator &pos, MeterKeys *meter
return true;
}
bool Telegram::parse_TPL_72(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
bool Telegram::parse_TPL_72(vector<uchar>::iterator &pos)
{
bool ok = parseLongTPL(pos);
if (!ok) return false;
potentiallyDecrypt(pos, meter_keys);
potentiallyDecrypt(pos);
header_size = distance(frame.begin(), pos);
int remaining = distance(pos, frame.end());
@ -1444,12 +1463,12 @@ bool Telegram::parse_TPL_79(vector<uchar>::iterator &pos)
return true;
}
bool Telegram::parse_TPL_7A(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
bool Telegram::parse_TPL_7A(vector<uchar>::iterator &pos)
{
bool ok = parseShortTPL(pos);
if (!ok) return false;
potentiallyDecrypt(pos, meter_keys);
potentiallyDecrypt(pos);
header_size = distance(frame.begin(), pos);
int remaining = distance(pos, frame.end());
@ -1459,7 +1478,7 @@ bool Telegram::parse_TPL_7A(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
return true;
}
bool Telegram::parseTPL(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
bool Telegram::parseTPL(vector<uchar>::iterator &pos)
{
int remaining = distance(pos, frame.end());
if (remaining == 0) return false;
@ -1480,10 +1499,10 @@ bool Telegram::parseTPL(vector<uchar>::iterator &pos, MeterKeys *meter_keys)
switch (tpl_ci)
{
case CI_Field_Values::TPL_72: return parse_TPL_72(pos, meter_keys);
case CI_Field_Values::TPL_72: return parse_TPL_72(pos);
case CI_Field_Values::TPL_78: return parse_TPL_78(pos);
case CI_Field_Values::TPL_79: return parse_TPL_79(pos);
case CI_Field_Values::TPL_7A: return parse_TPL_7A(pos, meter_keys);
case CI_Field_Values::TPL_7A: return parse_TPL_7A(pos);
case CI_Field_Values::MFCT_SPECIFIC:
{
header_size = distance(frame.begin(), pos);
@ -1517,8 +1536,9 @@ bool Telegram::parseHeader(vector<uchar> &input_frame)
return true;
}
bool Telegram::parse(vector<uchar> &input_frame, MeterKeys *meter_keys)
bool Telegram::parse(vector<uchar> &input_frame, MeterKeys *mk)
{
meter_keys = mk;
assert(meter_keys != NULL);
bool ok;
frame = input_frame;
@ -1540,7 +1560,7 @@ bool Telegram::parse(vector<uchar> &input_frame, MeterKeys *meter_keys)
// │ │
// └──────────────────────────────────────────────┘
ok = parseELL(pos, meter_keys);
ok = parseELL(pos);
if (!ok) return false;
// ┌──────────────────────────────────────────────┐
@ -1567,7 +1587,7 @@ bool Telegram::parse(vector<uchar> &input_frame, MeterKeys *meter_keys)
// │ │
// └──────────────────────────────────────────────┘
ok = parseTPL(pos, meter_keys);
ok = parseTPL(pos);
if (!ok) return false;
/*

14
src/wmbus.h
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@ -233,7 +233,8 @@ struct Telegram
int dll_mft {}; // Manufacturer 2 bytes
vector<uchar> dll_a; // A field 6 bytes
// The 6 a field bytes are composed of:
vector<uchar> a_field_address; // Address in BCD = 8 decimal 00000000...99999999 digits.
uchar dll_id_b[4] {}; // 4 bytes, address in BCD = 8 decimal 00000000...99999999 digits.
vector<uchar> dll_id; // 4 bytes, human readable order.
string id; // the address as a string.
int dll_version {}; // 1 byte
int dll_type {}; // 1 byte
@ -323,12 +324,13 @@ private:
bool is_simulated_ {};
bool parser_warns_ = true;
MeterKeys *meter_keys {};
bool parseDLL(std::vector<uchar>::iterator &pos);
bool parseELL(std::vector<uchar>::iterator &pos, MeterKeys *meter_keys);
bool parseELL(std::vector<uchar>::iterator &pos);
bool parseNWL(std::vector<uchar>::iterator &pos);
bool parseAFL(std::vector<uchar>::iterator &pos);
bool parseTPL(std::vector<uchar>::iterator &pos, MeterKeys *meter_keys);
bool parseTPL(std::vector<uchar>::iterator &pos);
void printDLL();
void printELL();
@ -336,11 +338,11 @@ private:
void printAFL();
void printTPL();
bool parse_TPL_72(vector<uchar>::iterator &pos, MeterKeys *meter_keys);
bool parse_TPL_72(vector<uchar>::iterator &pos);
bool parse_TPL_78(vector<uchar>::iterator &pos);
bool parse_TPL_79(vector<uchar>::iterator &pos);
bool parse_TPL_7A(vector<uchar>::iterator &pos, MeterKeys *meter_keys);
bool potentiallyDecrypt(vector<uchar>::iterator &pos, MeterKeys *meter_keys);
bool parse_TPL_7A(vector<uchar>::iterator &pos);
bool potentiallyDecrypt(vector<uchar>::iterator &pos);
bool parseTPLConfig(std::vector<uchar>::iterator &pos);
static string toStringFromELLSN(int sn);
static string toStringFromTPLConfig(int cfg);