QProcess::start() segfaults on empty program

Handle cases where QProcess::start() and startDetached() are passed a
null, empty, or "invalid" program string instead of crashing.

Task-number: 247865
Reviewed-by: Andreas Aardal Hanssen

2 files changed, 35 insertions, 0 deletions

diff --git a/src/corelib/io/qprocess.cpp b/src/corelib/io/qprocess.cpp
index a9d8ee2..f16f996 100644
--- a/src/corelib/io/qprocess.cpp
+++ b/src/corelib/io/qprocess.cpp
@@ -1601,6 +1601,13 @@ static QStringList parseCombinedArgString(const QString &program)
 void QProcess::start(const QString &program, OpenMode mode)
 {
     QStringList args = parseCombinedArgString(program);
+    if (args.isEmpty()) {
+        Q_D(QProcess);
+        d->processError = QProcess::FailedToStart;
+        setErrorString(tr("No program defined"));
+        emit error(d->processError);
+        return;
+    }
 
     QString prog = args.first();
     args.removeFirst();
@@ -1769,6 +1776,8 @@ bool QProcess::startDetached(const QString &program,
 bool QProcess::startDetached(const QString &program)
 {
     QStringList args = parseCombinedArgString(program);
+    if (args.isEmpty())
+        return false;
 
     QString prog = args.first();
     args.removeFirst();
diff --git a/tests/auto/qprocess/tst_qprocess.cpp b/tests/auto/qprocess/tst_qprocess.cpp
index f0dae5d..cb2b1bf 100644
--- a/tests/auto/qprocess/tst_qprocess.cpp
+++ b/tests/auto/qprocess/tst_qprocess.cpp
@@ -139,6 +139,8 @@ private slots:
     void switchReadChannels();
     void setWorkingDirectory();
     void startFinishStartFinish();
+    void invalidProgramString_data();
+    void invalidProgramString();
 
     // keep these at the end, since they use lots of processes and sometimes
     // caused obscure failures to occur in tests that followed them (esp. on the Mac)
@@ -2000,5 +2002,29 @@ void tst_QProcess::startFinishStartFinish()
     }
 }
 
+//-----------------------------------------------------------------------------
+void tst_QProcess::invalidProgramString_data()
+{
+    QTest::addColumn<QString>("programString");
+    QTest::newRow("null string") << QString();
+    QTest::newRow("empty string") << QString("");
+    QTest::newRow("only blank string") << QString("  ");
+}
+
+void tst_QProcess::invalidProgramString()
+{
+    QFETCH(QString, programString);
+    QProcess process;
+
+    qRegisterMetaType<QProcess::ProcessError>("QProcess::ProcessError");
+    QSignalSpy spy(&process, SIGNAL(error(QProcess::ProcessError)));
+
+    process.start(programString);
+    QCOMPARE(process.error(), QProcess::FailedToStart);
+    QCOMPARE(spy.count(), 1);
+
+    QVERIFY(!QProcess::startDetached(programString));
+}
+
 QTEST_MAIN(tst_QProcess)
 #include "tst_qprocess.moc"