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, 9 insertions, 18 deletions

diff --git a/libunwindstack/tests/MemoryLocalTest.cpp b/libunwindstack/tests/MemoryLocalTest.cpp
index 0ba5f1c37..ab999dafc 100644
--- a/libunwindstack/tests/MemoryLocalTest.cpp
+++ b/libunwindstack/tests/MemoryLocalTest.cpp
@@ -47,29 +47,20 @@ TEST(MemoryLocalTest, read) {
   }
 }
 
-TEST(MemoryLocalTest, read_string) {
-  std::string name("string_in_memory");
-
+TEST(MemoryLocalTest, read_illegal) {
   MemoryLocal local;
 
-  std::vector<uint8_t> dst(1024);
-  std::string dst_name;
-  ASSERT_TRUE(local.ReadString(reinterpret_cast<uint64_t>(name.c_str()), &dst_name));
-  ASSERT_EQ("string_in_memory", dst_name);
-
-  ASSERT_TRUE(local.ReadString(reinterpret_cast<uint64_t>(&name[7]), &dst_name));
-  ASSERT_EQ("in_memory", dst_name);
-
-  ASSERT_TRUE(local.ReadString(reinterpret_cast<uint64_t>(&name[7]), &dst_name, 10));
-  ASSERT_EQ("in_memory", dst_name);
-
-  ASSERT_FALSE(local.ReadString(reinterpret_cast<uint64_t>(&name[7]), &dst_name, 9));
+  std::vector<uint8_t> dst(100);
+  ASSERT_FALSE(local.Read(0, dst.data(), 1));
+  ASSERT_FALSE(local.Read(0, dst.data(), 100));
 }
 
-TEST(MemoryLocalTest, read_illegal) {
+TEST(MemoryLocalTest, read_overflow) {
   MemoryLocal local;
 
+  // On 32 bit this test doesn't necessarily cause an overflow. The 64 bit
+  // version will always go through the overflow check.
   std::vector<uint8_t> dst(100);
-  ASSERT_FALSE(local.Read(0, dst.data(), 1));
-  ASSERT_FALSE(local.Read(0, dst.data(), 100));
+  uint64_t value;
+  ASSERT_FALSE(local.Read(reinterpret_cast<uint64_t>(&value), dst.data(), SIZE_MAX));
 }