diff options
author | Harald Welte <laforge@osmocom.org> | 2024-02-18 11:05:45 +0100 |
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committer | Harald Welte <laforge@osmocom.org> | 2024-02-18 22:30:08 +0100 |
commit | efdf423a7f758987de249412e8e67ac94f9d09aa (patch) | |
tree | 528ca7ac2046739ca4d688e728ce8f54850a995b /pySim | |
parent | 979c837286d3e5fa41322d2f97c4a31494cb5da5 (diff) |
utils: Add function to verify Luhn check digits and to sanitize ICCIDs
Change-Id: I7812420cf97984dd834fca6a38c5e5ae113243cb
Diffstat (limited to 'pySim')
-rw-r--r-- | pySim/utils.py | 31 |
1 files changed, 30 insertions, 1 deletions
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 string 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@246tNt.com> # Copyright (C) 2021 Harald Welte <laforge@osmocom.org> @@ -446,6 +446,30 @@ def dec_iccid(ef: Hexstr) -> str: 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 @@ def calculate_luhn(cc) -> int: 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]: """ |