Add overflow checks in Memory objects.

Also change one of the reads to be explicitly ReadField instead of an
overloaded Read function.

Bug: 23762183

Test: Passes new unit tests.
Change-Id: Id848f7b632f67df0c5b7318d9e588942cfd2099a

1 files changed, 126 insertions, 0 deletions

diff --git a/libunwindstack/tests/MemoryTest.cpp b/libunwindstack/tests/MemoryTest.cpp
new file mode 100644
index 000000000..51b5d7db7
--- /dev/null
+++ b/libunwindstack/tests/MemoryTest.cpp
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2017 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 <stdint.h>
+#include <string.h>
+
+#include <string>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+#include "Memory.h"
+
+#include "MemoryFake.h"
+
+TEST(MemoryTest, read32) {
+  MemoryFakeAlwaysReadZero memory;
+
+  uint32_t data = 0xffffffff;
+  ASSERT_TRUE(memory.Read32(0, &data));
+  ASSERT_EQ(0U, data);
+}
+
+TEST(MemoryTest, read64) {
+  MemoryFakeAlwaysReadZero memory;
+
+  uint64_t data = 0xffffffffffffffffULL;
+  ASSERT_TRUE(memory.Read64(0, &data));
+  ASSERT_EQ(0U, data);
+}
+
+struct FakeStruct {
+  int one;
+  bool two;
+  uint32_t three;
+  uint64_t four;
+};
+
+TEST(MemoryTest, read_field) {
+  MemoryFakeAlwaysReadZero memory;
+
+  FakeStruct data;
+  memset(&data, 0xff, sizeof(data));
+  ASSERT_TRUE(memory.ReadField(0, &data, &data.one, sizeof(data.one)));
+  ASSERT_EQ(0, data.one);
+
+  memset(&data, 0xff, sizeof(data));
+  ASSERT_TRUE(memory.ReadField(0, &data, &data.two, sizeof(data.two)));
+  ASSERT_FALSE(data.two);
+
+  memset(&data, 0xff, sizeof(data));
+  ASSERT_TRUE(memory.ReadField(0, &data, &data.three, sizeof(data.three)));
+  ASSERT_EQ(0U, data.three);
+
+  memset(&data, 0xff, sizeof(data));
+  ASSERT_TRUE(memory.ReadField(0, &data, &data.four, sizeof(data.four)));
+  ASSERT_EQ(0U, data.four);
+}
+
+TEST(MemoryTest, read_field_fails) {
+  MemoryFakeAlwaysReadZero memory;
+
+  FakeStruct data;
+  memset(&data, 0xff, sizeof(data));
+
+  ASSERT_FALSE(memory.ReadField(UINT64_MAX, &data, &data.three, sizeof(data.three)));
+
+  // Field and start reversed, should fail.
+  ASSERT_FALSE(memory.ReadField(100, &data.two, &data, sizeof(data.two)));
+  ASSERT_FALSE(memory.ReadField(0, &data.two, &data, sizeof(data.two)));
+}
+
+TEST(MemoryTest, read_string) {
+  std::string name("string_in_memory");
+
+  MemoryFake memory;
+
+  memory.SetMemory(100, name.c_str(), name.size() + 1);
+
+  std::string dst_name;
+  ASSERT_TRUE(memory.ReadString(100, &dst_name));
+  ASSERT_EQ("string_in_memory", dst_name);
+
+  ASSERT_TRUE(memory.ReadString(107, &dst_name));
+  ASSERT_EQ("in_memory", dst_name);
+
+  // Set size greater than string.
+  ASSERT_TRUE(memory.ReadString(107, &dst_name, 10));
+  ASSERT_EQ("in_memory", dst_name);
+
+  ASSERT_FALSE(memory.ReadString(107, &dst_name, 9));
+}
+
+TEST(MemoryTest, read_string_error) {
+  std::string name("short");
+
+  MemoryFake memory;
+
+  // Save everything except the terminating '\0'.
+  memory.SetMemory(0, name.c_str(), name.size());
+
+  std::string dst_name;
+  // Read from a non-existant address.
+  ASSERT_FALSE(memory.ReadString(100, &dst_name));
+
+  // This should fail because there is no terminating '\0'.
+  ASSERT_FALSE(memory.ReadString(0, &dst_name));
+
+  // This should pass because there is a terminating '\0'.
+  memory.SetData8(name.size(), '\0');
+  ASSERT_TRUE(memory.ReadString(0, &dst_name));
+  ASSERT_EQ("short", dst_name);
+}