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GP: mixed PSK TLS PUT KEY (Amendment B Table 3-13)

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AES PSK + DES DEK for scp81, tested with sysmoEUICC1 C2T

Change-Id: I480a9d049a052aa5ae54fe6e2771dba44e89434d
This commit is contained in:
Eric Wild
2026-09-07 19:51:23 +02:00
parent c582b5fee3
commit 078ac2bf19
2 changed files with 237 additions and 19 deletions
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pySim/global_platform/__init__.py
+85 -19
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@@ -18,10 +18,12 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
import io
import hashlib
from copy import deepcopy
from typing import Optional, List, Dict, Tuple
from construct import Optional as COptional
from construct import Struct, GreedyRange, FlagsEnum, Int16ub, Int24ub, Padding, Bit, Const
from construct import Construct, stream_read, stream_write
from Cryptodome.Random import get_random_bytes
from Cryptodome.Cipher import DES, DES3, AES
from osmocom.utils import *
@@ -148,6 +150,24 @@ sw_table = {
},
}
class PutKeyLength(Construct):
"""A length field of a PUT KEY data field, GP CardSpec v2.3.1 11.8.2.3.1
- all lengths ASN.1 BER-TLV (ITU-T X.690 Section 8.1.3)
- except that the length 128 may also be coded on one byte as '80' for backwards compatibility
80 does not introduce the indefinite form here which is unused in GP as far as i know.
That legacy form is accepted when parsing, but never generated, which agrees with the spec"""
def _parse(self, stream, context, path):
first = stream_read(stream, 1, path)[0]
if first <= 0x80:
return first
return int.from_bytes(stream_read(stream, first & 0x7f, path), 'big')
def _build(self, obj, stream, context, path):
data = bertlv_encode_len(obj)
stream_write(stream, data, len(data), path)
return obj
# GlobalPlatform 2.1.1 Section 9.1.6
KeyType = Enum(Byte, des=0x80,
tls_psk=0x85, # v2.3.1 Section 11.1.8
@@ -602,8 +622,8 @@ class ADF_SD(CardADF):
See GlobalPlatform CardSpecification v2.3 Section 11.8 for details.
The KCV (Key Check Values) can either be explicitly specified using `--key-check`, or will
otherwise be automatically generated for DES and AES keys. You can suppress the latter using
`--suppress-key-check`.
otherwise be automatically generated for DES, AES and TLS-PSK keys. You can suppress the
latter using `--suppress-key-check`.
Example (SCP80 KIC/KID/KIK):
put_key --key-version-nr 1 --key-id 0x01 --key-type aes --key-data 000102030405060708090a0b0c0d0e0f
@@ -620,33 +640,73 @@ class ADF_SD(CardADF):
kdb = []
for i in range(0, len(opts.key_type)):
if opts.key_check and len(opts.key_check) > i:
kcv = opts.key_check[i]
kcv = h2b(opts.key_check[i])
elif opts.suppress_key_check:
kcv = ''
kcv = b''
else:
kcv_bin = compute_kcv(opts.key_type[i], h2b(opts.key_data[i])) or b''
kcv = b2h(kcv_bin)
if self._cmd.lchan.scc.scp:
# encrypted key data with DEK of current SCP
kcb = b2h(self._cmd.lchan.scc.scp.encrypt_key(h2b(opts.key_data[i])))
else:
# (for example) during personalization, DEK might not be required)
kcb = opts.key_data[i]
kdb.append({'key_type': opts.key_type[i], 'kcb': kcb, 'kcv': kcv})
kcv = compute_kcv(opts.key_type[i], h2b(opts.key_data[i])) or b''
kdb.append({'key_type': opts.key_type[i], 'clear_key': h2b(opts.key_data[i]), 'kcv': kcv})
p2 = opts.key_id
if len(opts.key_type) > 1:
p2 |= 0x80
self.put_key(opts.old_key_version_nr, opts.key_version_nr, p2, kdb)
# Table 11-68: Key Data Field - Format 1 (Basic Format)
KeyDataBasic = GreedyRange(Struct('key_type'/KeyType,
'kcb'/Prefixed(Int8ub, GreedyBytes),
'kcv'/Prefixed(Int8ub, GreedyBytes)))
# Table 11-68: Key Data Field - Format 1 (Basic Format). The key component block length is
# BER-TLV coded (Section 11.8.2.3.1), the key check value length is always '00' - '7F'.
KeyDataBasic = Struct('key_type'/KeyType,
'kcb'/Prefixed(PutKeyLength(), GreedyBytes),
'kcv'/Prefixed(Int8ub, GreedyBytes))
def put_key(self, old_kvn:int, kvn: int, kid: int, key_dict: dict) -> bytes:
@classmethod
def encode_key_data_basic(cls, key_type: str, kcb: bytes, kcv: bytes) -> bytes:
"""Generic Basic key data field, GP CardSpec v2.3 Table 11-68):
tag || L1 || <maybe L2> KCB || <1-byte length> KCV"""
return cls.KeyDataBasic.build({'key_type': key_type, 'kcb': kcb, 'kcv': kcv})
@classmethod
def encode_key_data_psk(cls, clear_key: bytes, ciphered_key: bytes, kcv: bytes) -> bytes:
"""Single PSK TLS '85' key data field per GP Amendment B 1.2, 3.9.1 / Table 3-13:
85 | L1 | <L2> <ciphered PSK key> | <KCV length> | <KCV>
- framing is like Basic Format, but the kcb is always GP CardSpec Table 11-70
so always with the length of the clear text key value, even without padding!
- 'ciphered_key' is DEK(block-padded clear key), no additional length prefix."""
kcb = bertlv_encode_len(len(clear_key)) + ciphered_key
return cls.encode_key_data_basic('tls_psk', kcb, kcv)
@classmethod
def build_put_key_data(cls, kvn: int, keys: List[dict], scp) -> bytes:
"""Assemble the PUT KEY data field, mixed PSK + DES DEK is supported:
- new KVN followed by one key data field per key.
- tls_psk keys per GP Amendment B
- other key types generic Basic format
Param 'keys' is a dict:
- 'key_type' (str)
- 'clear_key' (bytes)
- 'kcv' (bytes / empty).
'scp' may be None (e.g. during personalization, when the DEK may not be required)."""
key_data = kvn.to_bytes(1, 'big')
for k in keys:
clear = k['clear_key']
if k['key_type'] == 'tls_psk':
# len always part of the data see CardSpec Table 11-70 vs Table 11-71
if scp:
ciphered = scp.dek_encrypt(scp.pad_to_blocksize(clear))
else:
ciphered = clear
key_data += cls.encode_key_data_psk(clear, ciphered, k['kcv'])
else:
if scp:
ciphered = scp.encrypt_key(clear)
else:
# (for example) during personalization, DEK might not be required
ciphered = clear
key_data += cls.encode_key_data_basic(k['key_type'], ciphered, k['kcv'])
return key_data
def put_key(self, old_kvn:int, kvn: int, kid: int, keys: List[dict]) -> bytes:
"""Perform the GlobalPlatform PUT KEY command in order to store a new key on the card.
See GlobalPlatform CardSpecification v2.3 Section 11.8 for details."""
key_data = kvn.to_bytes(1, 'big') + build_construct(ADF_SD.AddlShellCommands.KeyDataBasic, key_dict)
key_data = self.build_put_key_data(kvn, keys, self._cmd.lchan.scc.scp)
hdr = "80D8%02x%02x%02x" % (old_kvn, kid, len(key_data))
data, _sw = self._cmd.lchan.scc.send_apdu_checksw(hdr + b2h(key_data) + "00")
return data
@@ -1065,10 +1125,16 @@ def compute_kcv_aes(key:bytes) -> bytes:
cipher = AES.new(key, AES.MODE_ECB)
return cipher.encrypt(plaintext)
def compute_kcv_psk(key:bytes) -> bytes:
# GP Amendment B v1.2, 3.9.1 / Table 3-13
# KCV of a PSK TLS key is the 3 highest-order bytes of the SHA-1 digest of the clear key value.
return hashlib.sha1(key).digest()
# dict is keyed by the string name of the KeyType enum above in this file
KCV_CALCULATOR = {
'aes': compute_kcv_aes,
'des': compute_kcv_des,
'tls_psk': compute_kcv_psk,
}
def compute_kcv(key_type: str, key: bytes) -> Optional[bytes]: