whytofly
/
qt6-bb10
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

QIODevice: fix narrowing conversions in debugBinaryString 

The debugBinaryString() function is a hexedit-like pretty-printer
which prints in increments of 16 octets, so it can go forever.

The old code had an overload set (QByteArray) and (ptr, qint64 size),
but made the (ptr, n) overload construct a QByteArray to call the QBA
overload. That's a narrowing conversion right there, except it can't
trigger because no machine can hold that much memory. But it may warn.

The code inside went on with further narrowing conversions to int,
this time, which does have an effect on 64-bit. Granted, you'd wait a
long time for this inefficient pretty-printer to write out more than
16Mi lines of hex dump, but it's wrong nonetheless, because narrowing
conversions work with modulo arithmetic and not saturation arithmetic,
so passing a buffer of INT_MAX + 1 size would print nothing, which
would probably cause some time lost hunting unrelated bugs.

So, fix the whole thing as follows:

- remove the QBA overload, it was never called

- loop over the full range of up to LLONG_MAX characters; if
  developers pass too much data, that's SEP

- remove the narrowing casts to qsizetype at the call sites (avoids
  modulo arithmetic)

As a drive-by, make the function static, and to get compilers to
actually see all this, make it [[maybe_unused]] instead of ifdef'ing
out.

Not picking back, as it's debug-only code.

Task-number: QTBUG-103525
Change-Id: I8b06466365d8c57b14535d8752428a614f244297
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
bb10
Marc Mutz 2022-08-18 17:24:34 +02:00
parent 66b633bbc1
commit f020c4ba51
1 changed files with 12 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
src/corelib/io/qiodevice.cpp
View File

@ -21,23 +21,23 @@ QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
#ifdef QIODEVICE_DEBUG
void debugBinaryString(const QByteArray &input)
[[maybe_unused]]
static void debugBinaryString(const char *input, qint64 maxlen)
{
QByteArray tmp;
int startOffset = 0;
for (int i = 0; i < input.size(); ++i) {
qlonglong startOffset = 0;
for (qint64 i = 0; i < maxlen; ++i) {
tmp += input[i];
if ((i % 16) == 15 || i == (input.size() - 1)) {
printf("\n%15d:", startOffset);
if ((i % 16) == 15 || i == (maxlen - 1)) {
printf("\n%15lld:", startOffset);
startOffset += tmp.size();
for (int j = 0; j < tmp.size(); ++j)
for (qsizetype j = 0; j < tmp.size(); ++j)
printf(" %02x", int(uchar(tmp[j])));
for (int j = tmp.size(); j < 16 + 1; ++j)
for (qsizetype j = tmp.size(); j < 16 + 1; ++j)
printf(" ");
for (int j = 0; j < tmp.size(); ++j)
for (qsizetype j = 0; j < tmp.size(); ++j)
printf("%c", isprint(int(uchar(tmp[j]))) ? tmp[j] : '.');
tmp.clear();
}
@ -45,12 +45,6 @@ void debugBinaryString(const QByteArray &input)
printf("\n\n");
}
void debugBinaryString(const char *data, qint64 maxlen)
{
debugBinaryString(QByteArray(data, maxlen));
}
#endif
#define Q_VOID
static void checkWarnMessage(const QIODevice *device, const char *function, const char *what)
@ -1334,7 +1328,7 @@ qint64 QIODevice::readLine(char *data, qint64 maxSize)
#if defined QIODEVICE_DEBUG
printf("%p \treturning %lld, d->pos = %lld, d->buffer.size() = %lld, size() = %lld\n",
this, readBytes, d->pos, d->buffer.size(), size());
debugBinaryString(data, qsizetype(readBytes));
debugBinaryString(data, readBytes);
#endif
return readBytes;
@ -1378,7 +1372,7 @@ qint64 QIODevicePrivate::readLine(char *data, qint64 maxSize)
#if defined QIODEVICE_DEBUG
printf("%p \tread from buffer: %lld bytes, last character read: %hhx\n", q,
readSoFar, data[readSoFar - 1]);
debugBinaryString(data, qsizetype(readSoFar));
debugBinaryString(data, readSoFar);
#endif
if (data[readSoFar - 1] == '\n') {
if (openMode & QIODevice::Text) {
@ -1405,7 +1399,7 @@ qint64 QIODevicePrivate::readLine(char *data, qint64 maxSize)
printf("%p \tread from readLineData: %lld bytes, readSoFar = %lld bytes\n", q,
readBytes, readSoFar);
if (readBytes > 0) {
debugBinaryString(data, qsizetype(readSoFar + readBytes));
debugBinaryString(data, readSoFar + readBytes);
}
#endif
if (readBytes < 0) {