qputenv: defend against non-NUL-terminated QByteArray values

The old code assumed that a QByteArray's data() is always
NUL-terminated. Due to the conflation of owners and non-owners in
QByteArray (but also in case we ever get efficient substringing), this
is not always the case, e.g. QByteArray::fromRawData() does not ensure
NUL-termination.

From QString::utf16(), we learn that the condition to check for is
QArrayData::isMutable(). After working around the fact that
QByteArray::data_ptr() doesn't exist for const QBAs and that empty
QBAs always refer to QByteArray::empty_, which is !isMutable(), we can
detect this situation and re-allocate without introducing new API.

This is the fix for Qt ≤ 6.4. For Qt 6.5, we'll port the function to
QByteArrayView.

Pick-to: 6.4 6.3 6.2 5.15
Fixes: QTBUG-105302
Change-Id: I3416535ab09d601e0e87b2767f2c024ba1217e64
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 5 insertions, 1 deletions

diff --git a/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp b/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp
index 77a7fa4194..f914ee5f23 100644
--- a/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp
+++ b/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp
@@ -60,7 +60,11 @@ void tst_QGetPutEnv::getSetCheck()
     QCOMPARE(sresult, QString());
 #endif
 
-    QVERIFY(qputenv(varName, QByteArray("supervalue")));
+    constexpr char varValueFullString[] = "supervalue123";
+    const auto varValueQBA = QByteArray::fromRawData(varValueFullString, sizeof varValueFullString - 4);
+    QCOMPARE_EQ(varValueQBA, "supervalue");
+
+    QVERIFY(qputenv(varName, varValueQBA));
 
     QVERIFY(qEnvironmentVariableIsSet(varName));
     QVERIFY(!qEnvironmentVariableIsEmpty(varName));