18 Feb
2024
18 Feb
'24
7:49 p.m.
laforge has uploaded this change for review. (
https://gerrit.osmocom.org/c/pysim/+/36009?usp=email )
Change subject: utils: Add function to verify Luhn check digits and to sanitize ICCIDs
......................................................................
utils: Add function to verify Luhn check digits and to sanitize ICCIDs
Change-Id: I7812420cf97984dd834fca6a38c5e5ae113243cb
---
M pySim/utils.py
M tests/test_utils.py
2 files changed, 56 insertions(+), 1 deletion(-)
git pull ssh://gerrit.osmocom.org:29418/pysim refs/changes/09/36009/1
diff --git a/pySim/utils.py b/pySim/utils.py
index 86874ba..afa476b 100644
--- a/pySim/utils.py
+++ b/pySim/utils.py
@@ -9,7 +9,7 @@
import datetime
import argparse
from io import BytesIO
-from typing import Optional, List, Dict, Any, Tuple, NewType
+from typing import Optional, List, Dict, Any, Tuple, NewType, Union
# Copyright (C) 2009-2010 Sylvain Munaut <tnt(a)246tNt.com>
# Copyright (C) 2021 Harald Welte <laforge(a)osmocom.org>
@@ -446,6 +446,30 @@
def enc_iccid(iccid: str) -> Hexstr:
return swap_nibbles(rpad(iccid, 20))
+def sanitize_iccid(iccid: Union[int, str]) -> str:
+ iccid = str(iccid)
+ if len(iccid) < 18:
+ raise ValueError('ICCID input value must be at least 18 digits')
+ if len(iccid) > 20:
+ raise ValueError('ICCID input value must be at most 20 digits')
+ if len(iccid) == 18:
+ # 18 digits means we must add a luhn check digit to reach 19 digits
+ iccid += str(calculate_luhn(iccid))
+ if len(iccid) == 20:
+ # 20 digits means we're actually exceeding E.118 by one digit, and
+ # the luhn check digit must already be included
+ verify_luhn(iccid)
+ if len(iccid) == 19:
+ # 19 digits means that it's either an in-spec 19-digits ICCID with
+ # its luhn check digit already present, or it's an out-of-spec 20-digit
+ # ICCID without that check digit...
+ try:
+ verify_luhn(iccid)
+ except ValueError:
+ # 19th digit was not luhn check digit; we must add it
+ iccid += str(calculate_luhn(iccid))
+ return iccid
+
def enc_plmn(mcc: Hexstr, mnc: Hexstr) -> Hexstr:
"""Converts integer MCC/MNC into 3 bytes for EF"""
@@ -606,6 +630,11 @@
for d in num[::-2]]) % 10
return 0 if check_digit == 10 else check_digit
+def verify_luhn(digits: str):
+ """Verify the Luhn check digit; raises ValueError if it is
incorrect."""
+ cd = calculate_luhn(digits[:-1])
+ if str(cd) != digits[-1]:
+ raise ValueError('Luhn check digit mismatch: should be %s but is %s' %
(str(cd), digits[-1]))
def mcc_from_imsi(imsi: str) -> Optional[str]:
"""
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 7609f80..75c8566 100755
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -236,5 +236,22 @@
self.assertEqual(utils.dgi_parse_len(b'\xfe\x0b'), (254,
b'\x0b'))
self.assertEqual(utils.dgi_parse_len(b'\xff\x00\xff\x0b'), (255,
b'\x0b'))
+class TestLuhn(unittest.TestCase):
+ def test_verify(self):
+ utils.verify_luhn('8988211000000530082')
+
+ def test_encode(self):
+ self.assertEqual(utils.calculate_luhn('898821100000053008'), 2)
+
+ def test_sanitize_iccid(self):
+ # 19 digits with correct luhn; we expect no change
+ self.assertEqual(utils.sanitize_iccid('8988211000000530082'),
'8988211000000530082')
+ # 20 digits with correct luhn; we expect no change
+ self.assertEqual(utils.sanitize_iccid('89882110000005300811'),
'89882110000005300811')
+ # 19 digits without correct luhn; we expect chck digit to be added
+ self.assertEqual(utils.sanitize_iccid('8988211000000530081'),
'89882110000005300811')
+ # 18 digits; we expect luhn check digit to be added
+ self.assertEqual(utils.sanitize_iccid('898821100000053008'),
'8988211000000530082')
+
if __name__ == "__main__":
unittest.main()
--
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Gerrit-Project: pysim
Gerrit-Branch: master
Gerrit-Change-Id: I7812420cf97984dd834fca6a38c5e5ae113243cb
Gerrit-Change-Number: 36009
Gerrit-PatchSet: 1
Gerrit-Owner: laforge <laforge(a)osmocom.org>
Gerrit-MessageType: newchange