libutils: fix overflow in SharedBuffer

See
https://code.google.com/p/android/issues/detail?id=181910

Bug: 22952485
Change-Id: Idcc7e581a69436c8a623659fbd9add9e5f0d4c74

1 files changed, 56 insertions, 0 deletions

diff --git a/libutils/SharedBufferTest.cpp b/libutils/SharedBufferTest.cpp
new file mode 100644
index 000000000..1919e771c
--- /dev/null
+++ b/libutils/SharedBufferTest.cpp
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <utils/SharedBuffer.h>
+
+#include <gtest/gtest.h>
+
+#include <memory>
+#include <stdint.h>
+
+TEST(SharedBufferTest, TestAlloc) {
+  EXPECT_DEATH(android::SharedBuffer::alloc(SIZE_MAX), "");
+  EXPECT_DEATH(android::SharedBuffer::alloc(SIZE_MAX - sizeof(android::SharedBuffer)), "");
+
+  // Make sure we don't die here.
+  // Check that null is returned, as we are asking for the whole address space.
+  android::SharedBuffer* buf =
+      android::SharedBuffer::alloc(SIZE_MAX - sizeof(android::SharedBuffer) - 1);
+  ASSERT_EQ(nullptr, buf);
+
+  buf = android::SharedBuffer::alloc(0);
+  ASSERT_NE(nullptr, buf);
+  ASSERT_EQ(0U, buf->size());
+  buf->release();
+}
+
+TEST(SharedBufferTest, TestEditResize) {
+  android::SharedBuffer* buf = android::SharedBuffer::alloc(10);
+  EXPECT_DEATH(buf->editResize(SIZE_MAX - sizeof(android::SharedBuffer)), "");
+  buf = android::SharedBuffer::alloc(10);
+  EXPECT_DEATH(buf->editResize(SIZE_MAX), "");
+
+  buf = android::SharedBuffer::alloc(10);
+  // Make sure we don't die here.
+  // Check that null is returned, as we are asking for the whole address space.
+  buf = buf->editResize(SIZE_MAX - sizeof(android::SharedBuffer) - 1);
+  ASSERT_EQ(nullptr, buf);
+
+  buf = android::SharedBuffer::alloc(10);
+  buf = buf->editResize(0);
+  ASSERT_EQ(0U, buf->size());
+  buf->release();
+}