a11y atspi: add null checks in table iface methods

Origin: upstream, https://invent.kde.org/qt/qt/qtbase/-/commit/076da096464a5d3f
Last-Update: 2025-03-24
Bug: https://bugs.debian.org/1081682

Add null checks to cover the cases where QAccessibleTableInterface::cellAt
returns nullptr (which happens e.g. when called with invalid indices via
AT-SPI) or where the cell object doesn't implement the
QAccessibleTableCellInterface, which would previously result in crashes.

Cherry-picked into 5.15 as it fixes a crash in popular accessibility client
software. Conflict resolution: remove C++17'isms (`if` with initializer).

Gbp-Pq: Name a11y_null_checks.diff

diff --git a/src/platformsupport/linuxaccessibility/atspiadaptor.cpp b/src/platformsupport/linuxaccessibility/atspiadaptor.cpp
index 9153fd20bbeed6c3dec355f79eed92ba0ae41b29..101ee12d314a864decb6f10d6e4da3e1cf0e51e2 100644 (file)
--- a/src/platformsupport/linuxaccessibility/atspiadaptor.cpp
+++ b/src/platformsupport/linuxaccessibility/atspiadaptor.cpp
@@ -2393,13 +2393,14 @@ bool AtSpiAdaptor::tableInterface(QAccessibleInterface *interface, const QString
         if (cols > 0) {
             row = index / cols;
             col = index % cols;
-            QAccessibleTableCellInterface *cell = interface->tableInterface()->cellAt(row, col)->tableCellInterface();
-            if (cell) {
-                row = cell->rowIndex();
-                col = cell->columnIndex();
-                rowExtents = cell->rowExtent();
-                colExtents = cell->columnExtent();
-                isSelected = cell->isSelected();
+            QAccessibleInterface *cell = interface->tableInterface()->cellAt(row, col);
+            QAccessibleTableCellInterface *cellIface = cell ? cell->tableCellInterface() : nullptr;
+            if (cellIface) {
+                row = cellIface->rowIndex();
+                col = cellIface->columnIndex();
+                rowExtents = cellIface->rowExtent();
+                colExtents = cellIface->columnExtent();
+                isSelected = cellIface->isSelected();
                 success = true;
             }
         }
@@ -2410,12 +2411,22 @@ bool AtSpiAdaptor::tableInterface(QAccessibleInterface *interface, const QString
     } else if (function == QLatin1String("GetColumnExtentAt")) {
         int row = message.arguments().at(0).toInt();
         int column = message.arguments().at(1).toInt();
-        connection.send(message.createReply(interface->tableInterface()->cellAt(row, column)->tableCellInterface()->columnExtent()));
+        int columnExtent = 0;
+        QAccessibleInterface *cell = interface->tableInterface()->cellAt(row, column);
+        QAccessibleTableCellInterface *cellIface = cell ? cell->tableCellInterface() : nullptr;
+        if (cellIface)
+            columnExtent = cellIface->columnExtent();
+        connection.send(message.createReply(columnExtent));
 
     } else if (function == QLatin1String("GetRowExtentAt")) {
         int row = message.arguments().at(0).toInt();
         int column = message.arguments().at(1).toInt();
-        connection.send(message.createReply(interface->tableInterface()->cellAt(row, column)->tableCellInterface()->rowExtent()));
+        int rowExtent = 0;
+        QAccessibleInterface *cell = interface->tableInterface()->cellAt(row, column);
+        QAccessibleTableCellInterface *cellIface = cell ? cell->tableCellInterface() : nullptr;
+        if (cellIface)
+            rowExtent = cellIface->rowExtent();
+        connection.send(message.createReply(rowExtent));
 
     } else if (function == QLatin1String("GetColumnHeader")) {
         int column = message.arguments().at(0).toInt();
@@ -2455,8 +2466,12 @@ bool AtSpiAdaptor::tableInterface(QAccessibleInterface *interface, const QString
     } else if (function == QLatin1String("IsSelected")) {
         int row = message.arguments().at(0).toInt();
         int column = message.arguments().at(1).toInt();
-        QAccessibleTableCellInterface* cell = interface->tableInterface()->cellAt(row, column)->tableCellInterface();
-        connection.send(message.createReply(cell->isSelected()));
+        bool isSelected = false;
+        QAccessibleInterface *cell = interface->tableInterface()->cellAt(row, column);
+        QAccessibleTableCellInterface *cellIface = cell ? cell->tableCellInterface() : nullptr;
+        if (cellIface)
+            isSelected = cellIface->isSelected();
+        connection.send(message.createReply(isSelected));
     } else if (function == QLatin1String("AddColumnSelection")) {
         int column = message.arguments().at(0).toInt();
         connection.send(message.createReply(interface->tableInterface()->selectColumn(column)));