test: Add fuzzer for kimageformats.

test/BUILD.bazel

@@ -98,3 +98,17 @@ cc_fuzz_test(
     tags = ["qt"],
     deps = ["//qtox/src:serialize"],
 )
+
+cc_fuzz_test(
+    name = "qimage_fuzz_test",
+    size = "small",
+    testonly = True,
+    srcs = ["chatlog/qimage_fuzz_test.cpp"],
+    copts = COPTS,
+    tags = ["qt"],
+    deps = [
+        "@kimageformats",
+        "@qt//:qt_core",
+        "@qt//:qt_gui",
+    ],
+)

test/chatlog/qimage_fuzz_test.cpp

@@ -0,0 +1,63 @@
+#include <QBuffer>
+#include <QByteArray>
+#include <QIODevice>
+#include <QImage>
+#include <QImageIOPlugin>
+#include <QPluginLoader>
+
+#include <cstddef>
+#include <cstdint>
+
+namespace {
+void test_fromData(const uint8_t* data, size_t size)
+{
+    if (size == 0) {
+        return;
+    }
+
+    const auto& plugins = QPluginLoader::staticInstances();
+    assert(plugins.size() < 256);
+    if (data[0] >= plugins.size()) {
+        return;
+    }
+
+    if (auto* imagePlugin = qobject_cast<QImageIOPlugin*>(plugins[data[0]])) {
+        qInstallMessageHandler([](QtMsgType, const QMessageLogContext&, const QString&) {
+            // Ignore messages
+        });
+
+        QByteArray ba(reinterpret_cast<const char*>(data + 1), size - 1);
+        QBuffer device(&ba);
+        device.open(QIODevice::ReadOnly);
+
+        QImage image;
+
+        auto* handler = imagePlugin->create(&device);
+        if (handler && handler->canRead()) {
+            handler->read(&image);
+        }
+        delete handler;
+    }
+}
+} // namespace
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
+{
+    test_fromData(data, size);
+    return 0;
+}
+
+Q_IMPORT_PLUGIN(ANIPlugin)
+Q_IMPORT_PLUGIN(EPSPlugin)
+Q_IMPORT_PLUGIN(HDRPlugin)
+Q_IMPORT_PLUGIN(PCXPlugin)
+Q_IMPORT_PLUGIN(PFMPlugin)
+Q_IMPORT_PLUGIN(PSDPlugin)
+Q_IMPORT_PLUGIN(PXRPlugin)
+Q_IMPORT_PLUGIN(QOIPlugin)
+Q_IMPORT_PLUGIN(RASPlugin)
+Q_IMPORT_PLUGIN(RGBPlugin)
+Q_IMPORT_PLUGIN(TGAPlugin)
+Q_IMPORT_PLUGIN(XCFPlugin)
+Q_IMPORT_PLUGIN(SoftimagePICPlugin)