personalization: EF_SMSP: keep same length as found in template

Change-Id: Id24752101ae82c4986209f4103cc9cbdcce8ce1d

README.md

@@ -97,7 +97,7 @@ Please install the following dependencies:
  - pyscard
  - pyserial
  - pytlv
- - pyyaml >= 5.1
+ - pyyaml >= 5.4
  - smpp.pdu (from `github.com/hologram-io/smpp.pdu`)
  - termcolor
 

pySim-prog.py

@@ -27,7 +27,6 @@
 import hashlib
 import argparse
 import os
-import random
 import re
 import sys
 import traceback
@@ -436,7 +435,7 @@ def gen_parameters(opts):
         if not re.match('^[0-9a-fA-F]{32}$', ki):
             raise ValueError('Ki needs to be 128 bits, in hex format')
     else:
-        ki = ''.join(['%02x' % random.randrange(0, 256) for i in range(16)])
+        ki = os.urandom(16).hex()
 
     # OPC (random)
     if opts.opc is not None:
@@ -447,7 +446,7 @@ def gen_parameters(opts):
     elif opts.op is not None:
         opc = derive_milenage_opc(ki, opts.op)
     else:
-        opc = ''.join(['%02x' % random.randrange(0, 256) for i in range(16)])
+        opc = os.urandom(16).hex()
 
     pin_adm = sanitize_pin_adm(opts.pin_adm, opts.pin_adm_hex)
 

pySim/esim/saip/personalization.py

@@ -618,10 +618,28 @@ class SmspTpScAddr(ConfigurableParameter):
             ef_smsp_dec['tp_sc_addr']['ton_npi']['type_of_number'] = 'international' if international else 'unknown'
             # ensure the parameter_indicators.tp_sc_addr is True
             ef_smsp_dec['parameter_indicators']['tp_sc_addr'] = True
+
+            # alpha_id padding: to make room for a human readable SMSC name that can be provisioned to the profile later
+            # on, alpha_id needs to be empty but padded 0xff to some length.
+            # - alpha_id is optional, setting alpha_id = '' ensures the IE is present.
+            # - the length of the file is 28+Y where Y is the length of the alpha_id -- here the intended length of our padding
+            #   (see 3GPP TS 31.102 4.2.27 EF.SMSP). So if we want a maximum length of alpha_id = 14, we set the total
+            #   file size to 28+14 = 42.
+            # - this file size has to go in two places: encode_record_bin() needs to know the length to encode the right
+            #   length of fillFileContent.
+            # - the f_smsp needs to show the right file size in the PES, as in
+            #      'ef-smsp': [('fileDescriptor', {'efFileSize': '2a', ...
+            #   (where 2a == 42)
+            # - To generate the right amount of fillFileContent, pass total_len=42 to encode_record_bin().
+            # - To show the right size in the PES, set f_smsp.rec_len = 42
             ef_smsp_dec['alpha_id'] = ''
-            # re-encode into the File body
-            f_smsp.body = ef_smsp.encode_record_bin(ef_smsp_dec, 1)
-            #print("SMSP  (new): %s" % f_smsp.body)
+
+            # we can set this to choose a fixed length:
+            #f_smsp.rec_len = 42
+            # but leave rec_len unchanged to keep the same length as was found in the eSIM template.
+
+            # re-encode into the File body.
+            f_smsp.body = ef_smsp.encode_record_bin(ef_smsp_dec, 1, total_len=f_smsp.rec_len)
             # re-generate the pe.decoded member from the File instance
             pe.file2pe(f_smsp)
 

pySim/ts_31_102.py

@@ -327,7 +327,7 @@ class EF_SUCI_Calc_Info(TransparentEF):
         """conversion method to generate list of {hnet_pubkey_identifier, hnet_pubkey} dicts
         from flat [{hnet_pubkey_identifier: }, {net_pubkey: }, ...] list"""
         out = []
-        while len(l):
+        while l:
             a = l.pop(0)
             b = l.pop(0)
             z = {**a, **b}

requirements.txt

@@ -6,7 +6,7 @@ jsonpath-ng
 construct>=2.10.70
 bidict
 pyosmocom>=0.0.12
-pyyaml>=5.1
+pyyaml>=5.4
 termcolor
 colorlog
 pycryptodomex

setup.py

@@ -26,7 +26,7 @@ setup(
         "construct >= 2.10.70",
         "bidict",
         "pyosmocom >= 0.0.12",
-        "pyyaml >= 5.1",
+        "pyyaml >= 5.4",
         "termcolor",
         "colorlog",
         "pycryptodomex",