Font: Fix potential use-after-free

The detach() call might deallocate the d-ptr we already
cached in the Q_D call, so move the Q_D call to after
detach()ing.
Even if it was not deallocated, as long as it was previously
shared, we would assign to the wrong private.

Change-Id: I9643ad72a7c7934cba9807220a9cf6c53c66ab13
Reviewed-by: Eskil Abrahamsen Blomfeldt <[email protected]>
Reviewed-by: Edward Welbourne <[email protected]>

1 files changed, 10 insertions, 10 deletions

diff --git a/src/gui/text/qfontvariableaxis.cpp b/src/gui/text/qfontvariableaxis.cpp
index 79a05b3617e..dfce507afe3 100644
--- a/src/gui/text/qfontvariableaxis.cpp
+++ b/src/gui/text/qfontvariableaxis.cpp
@@ -81,10 +81,10 @@ QFont::Tag QFontVariableAxis::tag() const
  */
 void QFontVariableAxis::setTag(QFont::Tag tag)
 {
-    Q_D(QFontVariableAxis);
-    if (d->tag == tag)
+    if (d_func()->tag == tag)
         return;
     detach();
+    Q_D(QFontVariableAxis);
     d->tag = tag;
 }
 
@@ -109,10 +109,10 @@ QString QFontVariableAxis::name() const
  */
 void QFontVariableAxis::setName(const QString &name)
 {
-    Q_D(QFontVariableAxis);
-    if (d->name == name)
+    if (d_func()->name == name)
         return;
     detach();
+    Q_D(QFontVariableAxis);
     d->name = name;
 }
 
@@ -138,10 +138,10 @@ qreal QFontVariableAxis::minimumValue() const
 */
 void QFontVariableAxis::setMinimumValue(qreal minimumValue)
 {
-    Q_D(QFontVariableAxis);
-    if (d->minimumValue == minimumValue)
+    if (d_func()->minimumValue == minimumValue)
         return;
     detach();
+    Q_D(QFontVariableAxis);
     d->minimumValue = minimumValue;
 }
 
@@ -167,10 +167,10 @@ qreal QFontVariableAxis::maximumValue() const
 */
 void QFontVariableAxis::setMaximumValue(qreal maximumValue)
 {
-    Q_D(QFontVariableAxis);
-    if (d->maximumValue == maximumValue)
+    if (d_func()->maximumValue == maximumValue)
         return;
     detach();
+    Q_D(QFontVariableAxis);
     d->maximumValue = maximumValue;
 }
 
@@ -196,10 +196,10 @@ qreal QFontVariableAxis::defaultValue() const
 */
 void QFontVariableAxis::setDefaultValue(qreal defaultValue)
 {
-    Q_D(QFontVariableAxis);
-    if (d->defaultValue == defaultValue)
+    if (d_func()->defaultValue == defaultValue)
         return;
     detach();
+    Q_D(QFontVariableAxis);
     d->defaultValue = defaultValue;
 }