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WMBus: add missing changes to mode 7 encyrption
git-svn-id: https://svn.fhem.de/fhem/trunk@20051 2b470e98-0d58-463d-a4d8-8e2adae1ed80
This commit is contained in:
kaihs
parent
c3b9d59283
commit
98b5ef3e48
@ -11,6 +11,8 @@ eval "use Crypt::Mode::CBC"; # cpan -i Crypt::Mode::CBC
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my $hasCBC = ($@)?0:1;
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eval "use Crypt::Mode::CTR"; # cpan -i Crypt::Mode::CTR
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my $hasCTR = ($@)?0:1;
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eval "use Digest::CMAC"; # cpan -i Digest::CMAC
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my $hasCMAC = ($@)?0:1;
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require Exporter;
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my @ISA = qw(Exporter);
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@ -1198,6 +1200,7 @@ sub getCRCsize {
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sub decodeConfigword($) {
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my $self = shift;
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#printf("cw: %01x %01x\n", $self->{cw_1}, $self->{cw_2});
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$self->{cw_parts}{mode} = ($self->{cw_2} & 0b00011111);
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#printf("mode: %02x\n", $self->{cw_parts}{mode});
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@ -1209,10 +1212,13 @@ sub decodeConfigword($) {
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$self->{cw_parts}{content} = ($self->{cw_1} & 0b00001100) >> 2;
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$self->{cw_parts}{repeated_access} = ($self->{cw_1} & 0b00000010) >> 1;
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$self->{cw_parts}{hops} = ($self->{cw_1} & 0b00000001);
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} #elsif ($self->{cw_parts}{mode} == 7) {
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# ToDo: wo kommt das dritte Byte her?
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# $self->{cw_parts}{mode} = $self->{cw} & 0b0000111100000000 >> 8;
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#}
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} elsif ($self->{cw_parts}{mode} == 7) {
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# configword ist 3 Bytes lang
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$self->{cw_parts}{key_id} = ($self->{cw_3} & 0b00001111);
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$self->{cw_parts}{dynamic_key} = ($self->{cw_3} & 0b01110000) >> 4;
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$self->{cw_parts}{content} = ($self->{cw_2} & 0b11000000) >> 6;
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$self->{cw_parts}{encrypted_blocks} = ($self->{cw_1} & 0b11110000) >> 4;
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}
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}
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sub decodeBCD($$$) {
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@ -1622,7 +1628,7 @@ sub decodePayload($$) {
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return 1;
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}
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sub decrypt($) {
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sub decrypt_mode5($) {
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my $self = shift;
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my $encrypted = shift;
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my $padding = 2;
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@ -1647,106 +1653,50 @@ sub decrypt($) {
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sub decrypt_mode7($) {
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my $self = shift;
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my $encrypted = shift;
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my $padding = 2;
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# see 9.2.4, page 59
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# generate dynamic key
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my $cmac = Digest::CMAC->new($self->{aeskey});
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#my $cmac = Digest::CMAC->new(pack("H*",'000102030405060708090A0B0C0D0E0F'));
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# The calculation of Kenc and Kmac for the meter:
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# Kenc = CMAC(MK, 0x00 ||C[7..0] ||C[15..8] ||C[23..16] ||C[31..24] ||ID_0||ID_1||ID_2||ID_3||0x07||0x07||0x07||0x07||0x07||0x07||0x07)
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# Where C[7..0] is the LSB and C[31..24] is the MSB (Big Endian) of the counter AFL.MCR.C from meter to other (gateway).
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$cmac->add(pack("H*", "00"));
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#$self->{afl}{mcr} = pack("H*", "b30a0000");
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$cmac->add($self->{afl}{mcr});
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#print "MCR " . unpack("H*", $self->{afl}{mcr}) . "\n";
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#print "identno " . unpack("H*", $self->{afield_identno}) . "\n";
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$cmac->add($self->{afield_identno});
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$cmac->add(pack("H*", "07070707070707"));
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#$cmac->add(pack("H*",'7856341207070707070707'));
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my $key = $cmac->digest;
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#printf("Dynamic key %s\n", $cmac->hexdigest);
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# see 9.2.3, page 52
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my $initVector = '';
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for (1..16) {
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$initVector .= pack('C',0x00);
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}
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my $cipher = Crypt::Mode::CBC->new('AES', 2);
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return $cipher->decrypt($encrypted, $self->{aeskey}, $initVector);
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}
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# Generate MAC of data
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#
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# Parameter 1: private key as byte string, 16bytes
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# Parameter 2: data fro which mac should be calculated in hexadecimal format, len variable
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# Parameter 3: length of MAC to be generated in bytes
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#
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# Returns: MAC in hexadecimal format
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#
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# This function currently supports data with lentgh of less then 16bytes,
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# MAC for longer data is untested but specified
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#
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# copied from 10_EnOcean.pm
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sub generateMAC($$$$) {
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my $self = shift;
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my $private_key = $_[0];
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my $data = $_[1];
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my $cmac_len = $_[2];
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#print "Calculating MAC for data $data\n";
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# Pack data to 16byte byte string, padd with 10..0 binary
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my $data_expanded = pack('H32', $data.'80');
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#print "Exp. data ".unpack('H32', $data_expanded)."\n";
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# Constants according to specification
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my $const_zero = pack('H32','00');
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my $const_rb = pack('H32', '00000000000000000000000000000087');
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# Encrypt zero data with private key to get L
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my $cipher = Crypt::Rijndael->new($private_key);
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my $l = $cipher->encrypt($const_zero);
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#print "L ".unpack('H32', $l)."\n";
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#print "L ".unpack('B128', $l)."\n";
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# Expand L to 128bit string
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my $l_bit = unpack('B128', $l);
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# K1 and K2 stored as 128bit string
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my $k1_bit;
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my $k2_bit;
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# K1 and K2 as binary
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my $k1;
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my $k2;
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# Store L << 1 in K1
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$l_bit =~ /^.(.{127})/;
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$k1_bit = $1.'0';
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$k1 = pack('B128', $k1_bit);
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# If MSB of L == 1, K1 = K1 XOR const_Rb
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if($l_bit =~ m/^1/) {
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#print "MSB of L is set\n";
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$k1 = $k1 ^ $const_rb;
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$k1_bit = unpack('B128', $k1);
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if (length($encrypted)%16 == 0) {
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# no padding if data length is multiple of blocksize
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$padding = 0;
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} else {
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#print "MSB of L is unset\n";
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$padding = 2;
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}
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# Store K1 << 1 in K2
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$k1_bit =~ /^.(.{127})/;
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$k2_bit = $1.'0';
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$k2 = pack('B128', $k2_bit);
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# If MSB of K1 == 1, K2 = K2 XOR const_Rb
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if($k1_bit =~ m/^1/) {
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#print "MSB of K1 is set\n";
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$k2 = $k2 ^ $const_rb;
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} else {
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#print "MSB of K1 is unset\n";
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#$encrypted = pack("H*","9058475F4BC91DF878B80A1B0F98B629024AAC727942BFC549233C0140829B93");
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#print unpack("H*", $encrypted) . "\n";
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my $cipher = Crypt::Mode::CBC->new('AES', $padding);
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return $cipher->decrypt($encrypted, $key, $initVector);
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}
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# XOR data with K2
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$data_expanded ^= $k2;
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# Encrypt data
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my $cmac = $cipher->encrypt($data_expanded);
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#print "CMAC ".unpack('H32', $cmac)."\n";
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# Extract specified len of MAC
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my $cmac_pattern = '^(.{'.($cmac_len * 2).'})';
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unpack('H32', $cmac) =~ /$cmac_pattern/;
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# Return MAC in hexadecimal format
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return uc($1);
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}
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sub decodeAFL($$) {
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my $self = shift;
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my $afl = shift;
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@ -1766,16 +1716,18 @@ sub decodeAFL($$) {
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if ($self->{afl}{fcl_mclp}) {
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# AFL Message Control Field (AFL.MCL)
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$self->{afl}{mcl} = unpack('C', substr($afl, $offset, 1));
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#printf "AFL MCL %01x\n", $self->{afl}{mcl};
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$offset += 1;
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$self->{afl}{mcl_mlmp} = ($self->{afl}{mcl} & 0b01000000) != 0;
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$self->{afl}{mcl_mcmp} = ($self->{afl}{mcl} & 0b00100000) != 0;
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$self->{afl}{mcl_kimp} = ($self->{afl}{mcl} & 0b00010000) != 0;
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$self->{afl}{mcl_at} = ($self->{afl}{mcl} & 0b00001111);
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$self->{afl}{mcl_at} = ($self->{afl}{mcl} & 0b00001100) >> 2;
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$self->{afl}{mcl_ato} = ($self->{afl}{mcl} & 0b00000011);
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}
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if ($self->{afl}{fcl_mcrp}) {
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# AFL Message Counter Field (AFL.MCR)
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$self->{afl}{mcr} = unpack('V', substr($afl, $offset));
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#printf "AFL MC %08x\n", $self->{afl}{mcr};
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#$self->{afl}{mcr} = unpack('N', substr($afl, $offset));
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$self->{afl}{mcr} = substr($afl, $offset, 4);
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$offset += 4;
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}
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if ($self->{afl}{fcl_mlp}) {
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@ -1783,23 +1735,16 @@ sub decodeAFL($$) {
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$self->{afl}{ml} = unpack('v', substr($afl, $offset));
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$offset += 2;
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}
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if ($self->{afl}{fcl_macp}) {
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# AFL MAC Field (AFL.MCL)
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# The length of the MAC field depends on the selected option AFL.MCL.AT indicated by the
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# AFL.MCL field.
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if ($self->{afl}{mcl_at} == 1) {
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# CMAC-AES128 (see 9.3.1)
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my $mac_len = 0;
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if ($self->{afl}{mcl_at} == 4) {
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$mac_len = 4;
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$self->{afl}{mac} = unpack('N', substr($afl, $offset, $mac_len));
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} elsif ($self->{afl}{mcl_at} == 5) {
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if ($self->{afl}{mcl_ato} == 1) {
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$mac_len = 8;
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$self->{afl}{mac} = (unpack('N', substr($afl, $offset, 4))) << 32 | ((unpack('N', substr($afl, $offset+4, 4))));
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} elsif ($self->{afl}{mcl_at} == 6) {
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$mac_len = 12;
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} elsif ($self->{afl}{mcl_at} == 7) {
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$mac_len = 16;
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#printf "AFL MAC %8x\n", $self->{afl}{mac};
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} else {
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# reserved
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}
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#printf "AFL MAC %16x\n", $self->{afl}{mac};
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$offset += $mac_len;
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}
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if ($self->{afl}{fcl_kip}) {
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@ -1827,6 +1772,7 @@ sub decodeApplicationLayer($) {
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$self->{cifield} = unpack('C', $applicationlayer);
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my $offset = 1;
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my $has_ell = 1;
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if ($self->{cifield} == CI_ELL_2) {
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# Extended Link Layer
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@ -1844,6 +1790,8 @@ sub decodeApplicationLayer($) {
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# Extended Link Layer
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($self->{ell}{cc}, $self->{ell}{access_no}, $self->{ell}{m2}, $self->{ell}{a2}, $self->{ell}{session_number}) = unpack('CCvC6V', substr($applicationlayer,$offset));
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$offset += 14;
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} else {
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$has_ell = 0;
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}
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if (exists($self->{ell}{session_number})) {
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@ -1920,6 +1868,7 @@ sub decodeApplicationLayer($) {
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# initialize some fields
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$self->{cw_1} = 0;
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$self->{cw_2} = 0;
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$self->{cw_3} = 0;
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$self->{status} = 0;
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$self->{statusstring} = "";
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$self->{access_no} = 0;
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@ -1928,15 +1877,18 @@ sub decodeApplicationLayer($) {
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#printf("CI Field %02x\n", $self->{cifield});
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# Config Word ist normalerweise 2 Bytes lang, nur bei encryption mode 7 drei Bytes
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# erstmal drei Bytes auslesen, aber den Offset nur um 2 Bytes erhöhen
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if ($self->{cifield} == CI_RESP_4 || $self->{cifield} == CI_RESP_SML_4) {
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# Short header
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($self->{access_no}, $self->{status}, $self->{cw_1}, $self->{cw_2}) = unpack('CCCC', substr($applicationlayer,$offset));
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($self->{access_no}, $self->{status}, $self->{cw_1}, $self->{cw_2}, $self->{cw_3}) = unpack('CCCCC', substr($applicationlayer,$offset));
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#printf("Short header access_no %x\n", $self->{access_no});
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$offset += 4;
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} elsif ($self->{cifield} == CI_RESP_12 || $self->{cifield} == CI_RESP_SML_12) {
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# Long header
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($self->{meter_id}, $self->{meter_man}, $self->{meter_vers}, $self->{meter_dev}, $self->{access_no}, $self->{status}, $self->{cw_1}, $self->{cw_2})
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= unpack('VvCCCCCC', substr($applicationlayer,$offset));
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($self->{meter_id}, $self->{meter_man}, $self->{meter_vers}, $self->{meter_dev}, $self->{access_no}, $self->{status}, $self->{cw_1}, $self->{cw_2}, $self->{cw_3})
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= unpack('VvCCCCCCC', substr($applicationlayer,$offset));
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$self->{meter_id} = sprintf("%08d", $self->{meter_id});
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$self->{meter_devtypestring} = $validDeviceTypes{$self->{meter_dev}} || 'unknown';
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$self->{meter_manufacturer} = uc($self->manId2ascii($self->{meter_man}));
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@ -2012,7 +1964,7 @@ sub decodeApplicationLayer($) {
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$self->{decrypted} = 1;
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}
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$payload = substr($applicationlayer, $offset);
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} elsif ($self->{cw_parts}{mode} == 5) {
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} elsif ($self->{cw_parts}{mode} == 5 || $self->{cw_parts}{mode} == 7) {
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# data is encrypted with AES 128, dynamic init vector
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# decrypt data before further processing
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$self->{isEncrypted} = 1;
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@ -2020,24 +1972,41 @@ sub decodeApplicationLayer($) {
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if ($self->{aeskey}) {
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if ($hasCBC) {
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# payload can be only partially encrypted.
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# decrypt only the encrypted part
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my $encrypted_length = $self->{cw_parts}{encrypted_blocks} * 16;
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#printf("encrypted payload %s\n", unpack("H*", substr($applicationlayer,$offset, $encrypted_length)));
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if ($self->{cw_parts}{mode} == 5) {
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eval {
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$payload = $self->decrypt(substr($applicationlayer, $offset, $encrypted_length))
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. substr($applicationlayer, $offset+$encrypted_length);
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$payload = $self->decrypt_mode5(substr($applicationlayer, $offset, $encrypted_length));
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};
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} else {
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# mode 7
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if ($hasCMAC) {
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$offset++; # account for codeword byte 3
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eval {
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$payload = $self->decrypt_mode7(substr($applicationlayer, $offset, $encrypted_length));
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}
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} else {
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$self->{errormsg} = 'Digest::CMAC is not installed, please install it (sudo cpan -i Digest::CMAC)';
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$self->{errorcode} = ERR_CIPHER_NOT_INSTALLED;
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return 0;
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}
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}
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if ($@) {
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#fatal decryption error occurred
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$self->{errormsg} = "fatal decryption error: $@";
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$self->{errormsg} = "fatal decryption error for mode " . $self->{cw_parts}{mode} . ": $@";
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$self->{errorcode} = ERR_DECRYPTION_FAILED;
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return 0;
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}
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# add unencrypted payload
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$payload .= substr($applicationlayer, $offset+$encrypted_length);
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#printf("decrypted payload %s\n", unpack("H*", $payload));
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if (unpack('n', $payload) == 0x2f2f) {
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$self->{decrypted} = 1;
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} else {
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# Decryption verification failed
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$self->{errormsg} = 'Decryption failed, wrong key?';
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$self->{errormsg} = sprintf('Decryption mode %d failed, wrong key?', $self->{cw_parts}{mode});
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$self->{errorcode} = ERR_DECRYPTION_FAILED;
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#printf("%x\n", unpack('n', $payload));
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return 0;
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@ -2052,7 +2021,6 @@ sub decodeApplicationLayer($) {
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$self->{errorcode} = ERR_NO_AESKEY;
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return 0;
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}
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} else {
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# error, encryption mode not implemented
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$self->{errormsg} = sprintf('Encryption mode %x not implemented', $self->{cw_parts}{mode});
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@ -2085,6 +2053,7 @@ sub decodeLinkLayer($$)
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}
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($self->{lfield}, $self->{cfield}, $self->{mfield}) = unpack('CCv', $linklayer);
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$self->{afield} = substr($linklayer,4,6);
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$self->{afield_identno} = substr($self->{afield}, 0, 4);
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$self->{afield_id} = sprintf("%08d", $self->decodeBCD(8,substr($linklayer,4,4)));
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($self->{afield_ver}, $self->{afield_type}) = unpack('CC', substr($linklayer,8,2));
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