forked from public/pysim
cat: properly decode IMEI/IMEISV IE
Currently BcdAdapter(GreedyBytes), i.e. a plain swapped nibble digit string, which is wrong, the IMEI IE is not a bcd string. See TS 124.008 10.5.1.4 figure 10.5.4 + table 10.5.4 It currently - decodes framing nibble as digit - encodes a 15 digit IMEI as 7 bytes, wrong len, dropped last digit Fix this, while at it add the 8.74 IMEISV as well + tests for the framing because the current round trip missed all of this. Change-Id: Iad7aea77513d413c338edc18ef1bcc37488ae849
This commit is contained in:
Eric Wild
+56
-3
@@ -22,7 +22,7 @@ from typing import List
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from bidict import bidict
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from construct import Int8ub, Int16ub, Byte, BitsInteger
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from construct import Struct, Enum, BitStruct, this
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from construct import Switch, GreedyRange, FlagsEnum
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from construct import Switch, GreedyRange, FlagsEnum, Adapter
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from osmocom.tlv import TLV_IE, COMPR_TLV_IE, BER_TLV_IE, TLV_IE_Collection
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from osmocom.construct import PlmnAdapter, BcdAdapter, GsmStringAdapter, TonNpi, GsmString, Bytes, GreedyBytes
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from osmocom.utils import b2h, h2b
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@@ -320,9 +320,54 @@ class FileList(COMPR_TLV_IE, tag=0x92):
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class LocationInformation(COMPR_TLV_IE, tag=0x93):
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pass
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# TS 102 223 Section 8.20
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class MobileIdentityAdapter(Adapter):
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"""TS 124.008 section 10.5.1.4 figure 10.5.4 + table 10.5.4
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NOT a plain BCD string:
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- bits 1-3 type of identity + odd/even bit 4
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- digit 1 in bits 5-8, following octets contain 2 digits, low nibble first
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- if even length: high nibble of last octet 1111
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So IMEI IE of 8 bytes is 15 digits + framing nibble."""
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# Table 10.5.4 bits 321
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TYPE_IMSI = 1
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TYPE_IMEI = 2
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TYPE_IMEISV = 3
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def __init__(self, subcon, type_of_identity: int):
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super().__init__(subcon)
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self.type_of_identity = type_of_identity
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def _decode(self, obj, context, path):
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data = bytes(obj)
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if not data:
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return ''
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# TS 24.008 figure 10.5.4: octet 3 holds type of identity (b1-3), odd/even (b4) and
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# digit 1 in its high nibble, the remaining digits follow BCD swapped from octet 4
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odd = bool(data[0] & 0x08) # bit 4: 1 = odd number of digits
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digits = '%x' % (data[0] >> 4) # bits 5-8: digit 1
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for octet in data[1:]:
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digits += '%x%x' % (octet & 0x0f, octet >> 4)
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if not odd:
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digits = digits[:-1] # drop the 1111 end mark
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return digits
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def _encode(self, obj, context, path):
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digits = str(obj)
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odd = len(digits) % 2
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first = (int(digits[0], 16) << 4) | (0x08 if odd else 0x00) | self.type_of_identity
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rest = digits[1:] if odd else digits[1:] + 'f'
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return bytes([first]) + bytes((int(rest[i+1], 16) << 4) | int(rest[i], 16)
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for i in range(0, len(rest), 2))
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# TS 102 223 Section 8.20, len is fixed at 8: "The IMEI is coded [..] as the
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# value part of the Mobile Identity IE as specified in TS 124 008", and the
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# IMEI itself is the 15 digits of TS 123 003.
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class IMEI(COMPR_TLV_IE, tag=0x94):
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_construct = BcdAdapter(GreedyBytes)
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_test_de_encode = [
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( '94081a32547698103254', '123456789012345' ),
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]
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_construct = MobileIdentityAdapter(GreedyBytes, MobileIdentityAdapter.TYPE_IMEI)
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# TS 102 223 Section 8.21
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class HelpRequest(COMPR_TLV_IE, tag=0x95):
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@@ -596,6 +641,14 @@ class UtranEutranMeasurementQualifier(COMPR_TLV_IE, tag=0xE9):
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eutran_inter_rat_utran=0x08,
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eutran_inter_rat_nr=0x09)
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# TS 102 223 Section 8.74, length is not fixed, because IMEISV is 16 digits per TS 123.003
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# -> even count needs the '1111' end mark and is 9 bytes long
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class IMEISV(COMPR_TLV_IE, tag=0xE2):
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_test_de_encode = [
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( 'e2091332547698103254f6', '1234567890123456' ),
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]
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_construct = MobileIdentityAdapter(GreedyBytes, MobileIdentityAdapter.TYPE_IMEISV)
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# TS 102 223 Section 8.75
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class NetworkSearchMode(COMPR_TLV_IE, tag=0xE5):
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_construct = Enum(Int8ub, manual=0, automatic=1)
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@@ -26,7 +26,66 @@ import unittest
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from osmocom.utils import b2h, h2b
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from pySim.cat import SupportedRadioAccessTechnologies
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from pySim.cat import IMEI, IMEISV, AccessTechnology, SupportedRadioAccessTechnologies
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class IMEI_Test(unittest.TestCase):
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"""TS 102 223 8.20: the IMEI IE is 8 bytes, coded as valie part of Mobile Identity IE from 124 008"""
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IMEI_15 = '123456789012345'
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ENCODED = '94081a32547698103254'
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def test_encode_is_eight_bytes(self):
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"""15 digits in 8 byte: 16 nibbles, one is type/parity framing."""
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tlv = IMEI(decoded=self.IMEI_15).to_tlv()
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self.assertEqual(b2h(tlv), self.ENCODED)
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self.assertEqual(tlv[1], 0x08) # spec len 8
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self.assertEqual(len(tlv) - 2, 8)
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def test_first_octet_framing(self):
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"""TS 24.008 table 10.5.4"""
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octet1 = IMEI(decoded=self.IMEI_15).to_tlv()[2]
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self.assertEqual(octet1 & 0x07, 2) # IMEI
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self.assertEqual((octet1 >> 3) & 0x01, 1) # odd
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self.assertEqual(octet1 >> 4, 1) # digit 1
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def test_decodes_to_the_raw_imei(self):
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"""strip framing nibble"""
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ie = IMEI()
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ie.from_tlv(h2b(self.ENCODED))
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self.assertEqual(ie.decoded, self.IMEI_15)
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def test_even_digit_count_uses_the_end_mark(self):
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""""end marker, IMEISV case"""
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ie = IMEI(decoded='1234567890123456')
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tlv = ie.to_tlv()
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self.assertEqual(tlv[2] >> 3 & 0x01, 0) # even
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self.assertEqual(tlv[-1] >> 4, 0x0f) # end mark
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back = IMEI()
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back.from_tlv(tlv)
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self.assertEqual(back.decoded, '1234567890123456')
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class IMEISV_Test(unittest.TestCase):
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"""TS 102 223 8.74, no fixed len, end marker"""
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IMEISV_16 = '1234567890123456'
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ENCODED = 'e2091332547698103254f6'
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def test_encode(self):
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self.assertEqual(b2h(IMEISV(decoded=self.IMEISV_16).to_tlv()), self.ENCODED)
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def test_type_of_identity_and_end_mark(self):
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value = IMEISV(decoded=self.IMEISV_16).to_tlv()[2:]
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self.assertEqual(value[0] & 0x07, 3) # IMEISV
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self.assertEqual((value[0] >> 3) & 0x01, 0) # even
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self.assertEqual(value[-1] >> 4, 0x0f) # end mark
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self.assertEqual(len(value), 9)
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def test_decode(self):
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ie = IMEISV()
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ie.from_tlv(h2b(self.ENCODED))
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self.assertEqual(ie.decoded, self.IMEISV_16)
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class SupportedRadioAccessTechnologies_Test(unittest.TestCase):
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@@ -21,6 +21,7 @@ import logging
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from osmocom.utils import b2h, h2b, all_subclasses
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from osmocom.tlv import *
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import pySim.cat
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import pySim.iso7816_4
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import pySim.ts_102_221
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import pySim.ts_102_222
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