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QXmlStreamWriter: Avoid writing invalid characters 

Some valid UTF-16 characters cannot be expressed in XML 1.0 and a
QString may contain invalid unicode. In both cases we should not write
the respective data to the output stream, as that generates invalid XML,
which then cannot be read back by QXmlStreamReader. In addition we
should report an error if we encounter them.

The change filters the incorrect strings from the output and introduces
an "encodingError" flag which is reported from hasError().

[ChangeLog][Important Behavior Changes] Characters invalid in XML, such
as 0x0 or 0xfffe, as well as strings containing unmatched UTF-16
surrogates are now suppressed from the output of QXmlStreamWriter and
cause the error flag to be set.

Task-number: QTBUG-63150
Change-Id: Ia29bab768fed9681dd68e8934da2a7e3fcdfc3cd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
bb10
Ulf Hermann 2017-09-12 17:31:31 +02:00
parent 71a2dd955c
commit 3b5b8f1d4a
2 changed files with 104 additions and 23 deletions
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81
src/corelib/xml/qxmlstream.cpp
View File

@ -2980,7 +2980,8 @@ public:
uint inEmptyElement :1;
uint lastWasStartElement :1;
uint wroteSomething :1;
uint hasError :1;
uint hasIoError :1;
uint hasEncodingError :1;
uint autoFormatting :1;
uint isCodecASCIICompatible :1;
QByteArray autoFormattingIndent;
@ -3016,7 +3017,8 @@ QXmlStreamWriterPrivate::QXmlStreamWriterPrivate(QXmlStreamWriter *q)
checkIfASCIICompatibleCodec();
inStartElement = inEmptyElement = false;
wroteSomething = false;
hasError = false;
hasIoError = false;
hasEncodingError = false;
lastWasStartElement = false;
lastNamespaceDeclaration = 1;
autoFormatting = false;
@ -3043,15 +3045,19 @@ void QXmlStreamWriterPrivate::checkIfASCIICompatibleCodec()
void QXmlStreamWriterPrivate::write(const QStringRef &s)
{
if (device) {
if (hasError)
if (hasIoError)
return;
#ifdef QT_NO_TEXTCODEC
QByteArray bytes = s.toLatin1();
#else
QByteArray bytes = encoder->fromUnicode(s.constData(), s.size());
if (encoder->hasFailure()) {
hasEncodingError = true;
return;
}
#endif
if (device->write(bytes) != bytes.size())
hasError = true;
hasIoError = true;
}
else if (stringDevice)
s.appendTo(stringDevice);
@ -3062,15 +3068,19 @@ void QXmlStreamWriterPrivate::write(const QStringRef &s)
void QXmlStreamWriterPrivate::write(const QString &s)
{
if (device) {
if (hasError)
if (hasIoError)
return;
#ifdef QT_NO_TEXTCODEC
QByteArray bytes = s.toLatin1();
#else
QByteArray bytes = encoder->fromUnicode(s);
if (encoder->hasFailure()) {
hasEncodingError = true;
return;
}
#endif
if (device->write(bytes) != bytes.size())
hasError = true;
hasIoError = true;
}
else if (stringDevice)
stringDevice->append(s);
@ -3084,25 +3094,47 @@ void QXmlStreamWriterPrivate::writeEscaped(const QString &s, bool escapeWhitespa
escaped.reserve(s.size());
for ( int i = 0; i < s.size(); ++i ) {
QChar c = s.at(i);
if (c.unicode() == '<' )
switch (c.unicode()) {
case '<':
escaped.append(QLatin1String("&lt;"));
else if (c.unicode() == '>' )
break;
case '>':
escaped.append(QLatin1String("&gt;"));
else if (c.unicode() == '&' )
break;
case '&':
escaped.append(QLatin1String("&amp;"));
else if (c.unicode() == '\"' )
break;
case '\"':
escaped.append(QLatin1String("&quot;"));
else if (escapeWhitespace && c.isSpace()) {
if (c.unicode() == '\n')
escaped.append(QLatin1String("&#10;"));
else if (c.unicode() == '\r')
escaped.append(QLatin1String("&#13;"));
else if (c.unicode() == '\t')
break;
case '\t':
if (escapeWhitespace)
escaped.append(QLatin1String("&#9;"));
else
escaped += c;
} else {
escaped += QChar(c);
break;
case '\n':
if (escapeWhitespace)
escaped.append(QLatin1String("&#10;"));
else
escaped += c;
break;
case '\v':
case '\f':
hasEncodingError = true;
break;
case '\r':
if (escapeWhitespace)
escaped.append(QLatin1String("&#13;"));
else
escaped += c;
break;
default:
if (c.unicode() > 0x1f && c.unicode() < 0xfffe)
escaped += c;
else
hasEncodingError = true;
break;
}
}
write(escaped);
@ -3112,11 +3144,11 @@ void QXmlStreamWriterPrivate::writeEscaped(const QString &s, bool escapeWhitespa
void QXmlStreamWriterPrivate::write(const char *s, int len)
{
if (device) {
if (hasError)
if (hasIoError)
return;
if (isCodecASCIICompatible) {
if (device->write(s, len) != len)
hasError = true;
hasIoError = true;
return;
}
}
@ -3400,15 +3432,18 @@ int QXmlStreamWriter::autoFormattingIndent() const
}
/*!
Returns \c true if the stream failed to write to the underlying device.
Returns \c true if writing failed.
This can happen if the stream failed to write to the underlying
device or if the data to be written contained invalid characters.
The error status is never reset. Writes happening after the error
occurred are ignored, even if the error condition is cleared.
occurred may be ignored, even if the error condition is cleared.
*/
bool QXmlStreamWriter::hasError() const
{
Q_D(const QXmlStreamWriter);
return d->hasError;
return d->hasIoError || d->hasEncodingError;
}
/*!

46
tests/auto/corelib/xml/qxmlstream/tst_qxmlstream.cpp
View File

@ -576,6 +576,7 @@ private slots:
void invalidStringCharacters_data() const;
void invalidStringCharacters() const;
void hasError() const;
void readBack() const;
private:
static QByteArray readFile(const QString &filename);
@ -1695,5 +1696,50 @@ void tst_QXmlStream::invalidStringCharacters_data() const
//
}
static bool isValidSingleTextChar(const ushort c)
{
// Conforms to https://www.w3.org/TR/REC-xml/#NT-Char - except for the high range, which is done
// with surrogates.
// Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
static const QPair<ushort, ushort> validRanges[] = {
QPair<ushort, ushort>(0x9, 0xb),
QPair<ushort, ushort>(0xd, 0xe),
QPair<ushort, ushort>(0x20, 0xd800),
QPair<ushort, ushort>(0xe000, 0xfffe)
};
for (const QPair<ushort, ushort> &range : validRanges) {
if (c >= range.first && c < range.second)
return true;
}
return false;
}
void tst_QXmlStream::readBack() const
{
for (ushort c = 0; c < std::numeric_limits<ushort>::max(); ++c) {
QBuffer buffer;
QVERIFY(buffer.open(QIODevice::WriteOnly));
QXmlStreamWriter writer(&buffer);
writer.writeStartDocument();
writer.writeTextElement("a", QString(QChar(c)));
writer.writeEndDocument();
buffer.close();
if (writer.hasError()) {
QVERIFY2(!isValidSingleTextChar(c), QByteArray::number(c));
} else {
QVERIFY2(isValidSingleTextChar(c), QByteArray::number(c));
QVERIFY(buffer.open(QIODevice::ReadOnly));
QXmlStreamReader reader(&buffer);
do {
reader.readNext();
} while (!reader.atEnd());
QVERIFY2(!reader.hasError(), QByteArray::number(c));
}
}
}
#include "tst_qxmlstream.moc"
// vim: et:ts=4:sw=4:sts=4