Adapt ASN.1 datetime parsing to use the new century control

It previously had to kludge a 1900-to-1999 date into a 1950-to-2049
range; it can now tell QDTP to do that for it. In particular, this
fixes a problem with 00-02-29, which failed to parse using 1900 as
base year so couldn't be corrected to 2000-02-29, which is now the
date it finds directly.

Task-number: QTBUG-46843
Change-Id: I7ac936bdfb15b78daed5d237c5d921c800af4951
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 9 insertions, 12 deletions

diff --git a/src/plugins/tls/shared/qasn1element.cpp b/src/plugins/tls/shared/qasn1element.cpp
index 8d4d908e53..97be46866d 100644
--- a/src/plugins/tls/shared/qasn1element.cpp
+++ b/src/plugins/tls/shared/qasn1element.cpp
@@ -225,31 +225,28 @@ QDateTime QAsn1Element::toDateTime() const
         return result;
 
     if (mType == UtcTimeType && mValue.size() == 13) {
-        const QLatin1StringView inputView(mValue);
-        QDate date = QDate::fromString(inputView.first(6), u"yyMMdd");
-        if (!date.isValid())
-            return result;
         // RFC 2459:
         //   Where YY is greater than or equal to 50, the year shall be
         //   interpreted as 19YY; and
         //
         //   Where YY is less than 50, the year shall be interpreted as 20YY.
         //
-        // QDateTime interprets the 'yy' format as 19yy, so we may need to adjust
-        // the year (bring it in the [1950, 2049] range).
-        if (date.year() < 1950)
-            date = date.addYears(100);
+        // so use 1950 as base year.
+        constexpr int rfc2459CenturyStart = 1950;
+        const QLatin1StringView inputView(mValue);
+        QDate date = QDate::fromString(inputView.first(6), u"yyMMdd", rfc2459CenturyStart);
+        if (!date.isValid())
+            return result;
 
-        Q_ASSERT(date.year() >= 1950);
-        Q_ASSERT(date.year() <= 2049);
+        Q_ASSERT(date.year() >= rfc2459CenturyStart);
+        Q_ASSERT(date.year() < 100 + rfc2459CenturyStart);
 
         QTime time = QTime::fromString(inputView.sliced(6, 6), u"HHmmss");
         if (!time.isValid())
             return result;
         result = QDateTime(date, time, QTimeZone::UTC);
     } else if (mType == GeneralizedTimeType && mValue.size() == 15) {
-        result = QDateTime::fromString(QString::fromLatin1(mValue),
-                                       u"yyyyMMddHHmmsst");
+        result = QDateTime::fromString(QString::fromLatin1(mValue), u"yyyyMMddHHmmsst");
     }
 
     return result;