Refactor expiration date extraction logic in certificate utility to improve handling of ASN.1 date formats. Update to correctly identify and parse "not after" dates for both UTCTime and GeneralizedTime formats.

This commit is contained in:
Mauricio Siu 2025-04-26 23:37:49 -06:00
parent dc03ba73b3
commit d6daa5677a

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@ -13,53 +13,65 @@ export const extractExpirationDate = (certData: string): Date | null => {
bytes[i] = binaryStr.charCodeAt(i);
}
let dateFound = 0;
// ASN.1 tag for UTCTime is 0x17, GeneralizedTime is 0x18
// We need to find the second occurrence of either tag as it's the "not after" (expiration) date
let dateFound = false;
for (let i = 0; i < bytes.length - 2; i++) {
if (bytes[i] === 0x17 || bytes[i] === 0x18) {
const dateType = bytes[i];
const dateLength = bytes[i + 1];
if (typeof dateLength === "undefined") continue;
// Look for sequence containing validity period (0x30)
if (bytes[i] === 0x30) {
// Check next bytes for UTCTime or GeneralizedTime
let j = i + 1;
while (j < bytes.length - 2) {
if (bytes[j] === 0x17 || bytes[j] === 0x18) {
const dateType = bytes[j];
const dateLength = bytes[j + 1];
if (typeof dateLength === "undefined") break;
if (dateFound === 0) {
dateFound++;
i += dateLength + 1;
continue;
if (!dateFound) {
// Skip "not before" date
dateFound = true;
j += dateLength + 2;
continue;
}
// Found "not after" date
let dateStr = "";
for (let k = 0; k < dateLength; k++) {
const charCode = bytes[j + 2 + k];
if (typeof charCode === "undefined") continue;
dateStr += String.fromCharCode(charCode);
}
if (dateType === 0x17) {
// UTCTime (YYMMDDhhmmssZ)
const year = Number.parseInt(dateStr.slice(0, 2));
const fullYear = year >= 50 ? 1900 + year : 2000 + year;
return new Date(
Date.UTC(
fullYear,
Number.parseInt(dateStr.slice(2, 4)) - 1,
Number.parseInt(dateStr.slice(4, 6)),
Number.parseInt(dateStr.slice(6, 8)),
Number.parseInt(dateStr.slice(8, 10)),
Number.parseInt(dateStr.slice(10, 12)),
),
);
}
// GeneralizedTime (YYYYMMDDhhmmssZ)
return new Date(
Date.UTC(
Number.parseInt(dateStr.slice(0, 4)),
Number.parseInt(dateStr.slice(4, 6)) - 1,
Number.parseInt(dateStr.slice(6, 8)),
Number.parseInt(dateStr.slice(8, 10)),
Number.parseInt(dateStr.slice(10, 12)),
Number.parseInt(dateStr.slice(12, 14)),
),
);
}
j++;
}
let dateStr = "";
for (let j = 0; j < dateLength; j++) {
const charCode = bytes[i + 2 + j];
if (typeof charCode === "undefined") continue;
dateStr += String.fromCharCode(charCode);
}
if (dateType === 0x17) {
// UTCTime (YYMMDDhhmmssZ)
const year = Number.parseInt(dateStr.slice(0, 2));
const fullYear = year >= 50 ? 1900 + year : 2000 + year;
return new Date(
Date.UTC(
fullYear,
Number.parseInt(dateStr.slice(2, 4)) - 1,
Number.parseInt(dateStr.slice(4, 6)),
Number.parseInt(dateStr.slice(6, 8)),
Number.parseInt(dateStr.slice(8, 10)),
Number.parseInt(dateStr.slice(10, 12)),
),
);
}
// GeneralizedTime (YYYYMMDDhhmmssZ)
return new Date(
Date.UTC(
Number.parseInt(dateStr.slice(0, 4)),
Number.parseInt(dateStr.slice(4, 6)) - 1,
Number.parseInt(dateStr.slice(6, 8)),
Number.parseInt(dateStr.slice(8, 10)),
Number.parseInt(dateStr.slice(10, 12)),
Number.parseInt(dateStr.slice(12, 14)),
),
);
}
}
return null;