QDateTime: Limit string processing to known boundaries

We were treating the input as if it was always reasonably good.
Since we know the max boundaries anyway lets just stop processing
when those are reached

Fixes: QTBUG-97489
Change-Id: Ibb78d6d51ad58454b2007ab46d54116ca0be5448
Reviewed-by: Robert Löhning <robert.loehning@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 18 insertions, 6 deletions

diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp
index b537bddd1e..30c83e09d9 100644
--- a/src/corelib/time/qdatetime.cpp
+++ b/src/corelib/time/qdatetime.cpp
@@ -151,8 +151,13 @@ static ParsedRfcDateTime rfcDateImpl(QStringView s)
     ParsedRfcDateTime result;
 
     QVarLengthArray<QStringView, 6> words;
-    s.tokenize(u' ', Qt::SkipEmptyParts).toContainer(words);
-    if (words.size() < 3 || words.size() > 6)
+
+    auto tokens = s.tokenize(u' ', Qt::SkipEmptyParts);
+    auto it = tokens.begin();
+    for (int i = 0; i < 6 && it != tokens.end(); ++i, ++it)
+        words.emplace_back(*it);
+
+    if (words.size() < 3 || it != tokens.end())
         return result;
     const QChar colon(u':');
     bool ok = true;
@@ -1481,9 +1486,12 @@ QDate QDate::fromString(QStringView string, Qt::DateFormat format)
     case Qt::TextDate: {
         // Documented as "ddd MMM d yyyy"
         QVarLengthArray<QStringView, 4> parts;
-        string.tokenize(u' ', Qt::SkipEmptyParts).toContainer(parts);
+        auto tokens = string.tokenize(u' ', Qt::SkipEmptyParts);
+        auto it = tokens.begin();
+        for (int i = 0; i < 4 && it != tokens.end(); ++i, ++it)
+            parts.emplace_back(*it);
 
-        if (parts.count() != 4)
+        if (parts.size() != 4 || it != tokens.end())
             return QDate();
 
         bool ok = false;
@@ -5119,11 +5127,15 @@ QDateTime QDateTime::fromString(QStringView string, Qt::DateFormat format)
     }
     case Qt::TextDate: {
         QVarLengthArray<QStringView, 6> parts;
-        string.tokenize(u' ', Qt::SkipEmptyParts).toContainer(parts);
+
+        auto tokens = string.tokenize(u' ', Qt::SkipEmptyParts);
+        auto it = tokens.begin();
+        for (int i = 0; i < 6 && it != tokens.end(); ++i, ++it)
+            parts.emplace_back(*it);
 
         // Documented as "ddd MMM d HH:mm:ss yyyy" with optional offset-suffix;
         // and allow time either before or after year.
-        if (parts.count() < 5 || parts.count() > 6)
+        if (parts.count() < 5 || it != tokens.end())
             return QDateTime();
 
         // Year and time can be in either order.