mirror
/
wmbusmeters
kopia lustrzana https://github.com/weetmuts/wmbusmeters
1
0
Forkuj 0
Kod Zgłoszenia Projekty Wydania Wiki Aktywność

Now handles partially encrypted AES CBC telegrams.

pull/139/head
Fredrik Öhrström 2020-07-09 14:51:28 +02:00
rodzic e84eb18cfa
commit 0e08f83e45
2 zmienionych plików z 49 dodań i 19 usunięć
Pokaż statystyki Ściągnij plik aktualizacji Ściągnij plik porównania Expand all files Collapse all files

7
src/wmbus.cc
Wyświetl plik

@ -1255,12 +1255,13 @@ bool Telegram::parseTPLConfig(std::vector<uchar>::iterator &pos)
bool has_cfg_ext = false;
string info = toStringFromTPLConfig(tpl_cfg);
info += " ";
if (tpl_sec_mode == TPLSecurityMode::AES_CBC_IV) // Security mode 5
{
tpl_num_encr_blocks = (tpl_cfg >> 4) & 0x0f;
}
if (tpl_sec_mode == TPLSecurityMode::AES_CBC_NO_IV) // Security mode 7
{
tpl_num_encr_blocks = (tpl_cfg >> 4) & 0x0f;
info += "NEB=";
info += to_string(tpl_num_encr_blocks);
info += " ";
has_cfg_ext = true;
}
addExplanationAndIncrementPos(pos, 2, "%02x%02x tpl-cfg %04x (%s)", cfg1, cfg2, tpl_cfg, info.c_str());

61
src/wmbus_utils.cc
Wyświetl plik

@ -101,16 +101,24 @@ bool decrypt_TPL_AES_CBC_IV(Telegram *t, vector<uchar> &frame, vector<uchar>::it
frame.erase(pos, frame.end());
debugPayload("(TPL) decrypting", buffer);
size_t len = buffer.size();
if (t->tpl_num_encr_blocks)
{
len = t->tpl_num_encr_blocks*16;
}
debug("(TPL) num encrypted blocks %d (%d bytes and remaining unencrypted %d bytes)\n",
t->tpl_num_encr_blocks, len, buffer.size()-len);
// The content should be a multiple of 16 since we are using AES CBC mode.
if (buffer.size() % 16 != 0)
if (len % 16 != 0)
{
warning("(TPL) warning: decryption received non-multiple of 16 bytes! "
"Got %zu bytes shrinking message to %zu bytes.\n",
buffer.size(), buffer.size() - buffer.size() % 16);
while (buffer.size() % 16 != 0)
{
buffer.pop_back();
}
len, len - len % 16);
len -= len % 16;
assert (len % 16 == 0);
}
uchar iv[16];
@ -129,10 +137,16 @@ bool decrypt_TPL_AES_CBC_IV(Telegram *t, vector<uchar> &frame, vector<uchar>::it
uchar buffer_data[buffer.size()];
memcpy(buffer_data, &buffer[0], buffer.size());
uchar decrypted_data[buffer.size()];
AES_CBC_decrypt_buffer(decrypted_data, buffer_data, buffer.size(), &aeskey[0], iv);
AES_CBC_decrypt_buffer(decrypted_data, buffer_data, len, &aeskey[0], iv);
frame.insert(frame.end(), decrypted_data, decrypted_data+buffer.size());
debugPayload("(TPL) decrypted", frame, pos);
frame.insert(frame.end(), decrypted_data, decrypted_data+len);
debugPayload("(TPL) decrypted ", frame, pos);
if (len < buffer.size())
{
frame.insert(frame.end(), buffer_data+len, buffer_data+buffer.size());
debugPayload("(TPL) appended ", frame, pos);
}
return true;
}
@ -145,16 +159,24 @@ bool decrypt_TPL_AES_CBC_NO_IV(Telegram *t, vector<uchar> &frame, vector<uchar>:
frame.erase(pos, frame.end());
debugPayload("(TPL) decrypting", buffer);
size_t len = buffer.size();
if (t->tpl_num_encr_blocks)
{
len = t->tpl_num_encr_blocks*16;
}
debug("(TPL) num encrypted blocks %d (%d bytes and remaining unencrypted %d bytes)\n",
t->tpl_num_encr_blocks, len, buffer.size()-len);
// The content should be a multiple of 16 since we are using AES CBC mode.
if (buffer.size() % 16 != 0)
if (len % 16 != 0)
{
warning("(TPL) warning: decryption received non-multiple of 16 bytes! "
"Got %zu bytes shrinking message to %zu bytes.\n",
buffer.size(), buffer.size() - buffer.size() % 16);
while (buffer.size() % 16 != 0)
{
buffer.pop_back();
}
len, len - len % 16);
len -= len % 16;
assert (len % 16 == 0);
}
uchar iv[16];
@ -170,6 +192,13 @@ bool decrypt_TPL_AES_CBC_NO_IV(Telegram *t, vector<uchar> &frame, vector<uchar>:
AES_CBC_decrypt_buffer(decrypted_data, buffer_data, buffer.size(), &aeskey[0], iv);
frame.insert(frame.end(), decrypted_data, decrypted_data+buffer.size());
debugPayload("(TPL) decrypted", frame, pos);
debugPayload("(TPL) decrypted ", frame, pos);
if (len < buffer.size())
{
frame.insert(frame.end(), buffer_data+len, buffer_data+buffer.size());
debugPayload("(TPL) appended ", frame, pos);
}
return true;
}