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Fix QString::vasprintf for strings > 2GiB

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Both format strings > 2GiB, as well as result strings > 2Gi characters
were affected by the append_utf8() helper function being left unported
from int to qsizetype.

There were actually two bugs in that 5LOC function:

1. The len argument was an int, but the caller feeds a difference of
   pointers (even explicitly cast to qsizetype) to the function, so
   any stretch of verbatim text > 2GiB in the format would cause the
   output string to be corrupted.

2. If the result string was already > 2Gi characters in size, a call
   to append_utf8() would truncate it mod INT_MAX, because the
   string's size() was stored in an int variable and the used in a
   resize() call.

Task-number: QTBUG-103531
Change-Id: I0a09d27b7782093d3f8ea17bb621ff8dad375072
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
(cherry picked from commit f73833809b87feb4046c7bdc1fedb3b3a14e80ec)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Marc Mutz 2022-07-20 22:06:36 +02:00 committed by Qt Cherry-pick Bot
parent 0d69de55c3
commit 4c5533bba3
1 changed files with 2 additions and 2 deletions
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4
src/corelib/text/qstring.cpp
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@ -6720,9 +6720,9 @@ QString QString::asprintf(const char *cformat, ...)
return s; return s;
} }
static void append_utf8(QString &qs, const char *cs, int len) static void append_utf8(QString &qs, const char *cs, qsizetype len)
{ {
const int oldSize = qs.size(); const qsizetype oldSize = qs.size();
qs.resize(oldSize + len); qs.resize(oldSize + len);
const QChar *newEnd = QUtf8::convertToUnicode(qs.data() + oldSize, QByteArrayView(cs, len)); const QChar *newEnd = QUtf8::convertToUnicode(qs.data() + oldSize, QByteArrayView(cs, len));
qs.resize(newEnd - qs.constData()); qs.resize(newEnd - qs.constData());