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, 7 insertions, 27 deletions

diff --git a/libunwindstack/tests/MemoryRangeTest.cpp b/libunwindstack/tests/MemoryRangeTest.cpp
index d636ec497..ee5ba018b 100644
--- a/libunwindstack/tests/MemoryRangeTest.cpp
+++ b/libunwindstack/tests/MemoryRangeTest.cpp
@@ -17,6 +17,7 @@
 #include <stdint.h>
 #include <string.h>
 
+#include <memory>
 #include <vector>
 
 #include <gtest/gtest.h>
@@ -65,35 +66,14 @@ TEST_F(MemoryRangeTest, read_near_limit) {
   ASSERT_FALSE(range.Read(1020, dst.data(), 5));
   ASSERT_FALSE(range.Read(1024, dst.data(), 1));
   ASSERT_FALSE(range.Read(1024, dst.data(), 1024));
-}
-
-TEST_F(MemoryRangeTest, read_string_past_end) {
-  std::string name("0123456789");
-  memory_->SetMemory(0, name);
-
-  // Verify a read past the range fails.
-  MemoryRange range(memory_, 0, 5);
-  std::string dst_name;
-  ASSERT_FALSE(range.ReadString(0, &dst_name));
-}
-
-TEST_F(MemoryRangeTest, read_string_to_end) {
-  std::string name("0123456789");
-  memory_->SetMemory(30, name);
 
-  // Verify the range going to the end of the string works.
-  MemoryRange range(memory_, 30, 30 + name.size() + 1);
-  std::string dst_name;
-  ASSERT_TRUE(range.ReadString(0, &dst_name));
-  ASSERT_EQ("0123456789", dst_name);
+  // Verify that reading up to the end works.
+  ASSERT_TRUE(range.Read(1020, dst.data(), 4));
 }
 
-TEST_F(MemoryRangeTest, read_string_fencepost) {
-  std::string name("0123456789");
-  memory_->SetMemory(10, name);
+TEST_F(MemoryRangeTest, read_overflow) {
+  std::vector<uint8_t> buffer(100);
 
-  // Verify the range set to one byte less than the end of the string fails.
-  MemoryRange range(memory_, 10, 10 + name.size());
-  std::string dst_name;
-  ASSERT_FALSE(range.ReadString(0, &dst_name));
+  std::unique_ptr<MemoryRange> overflow(new MemoryRange(new MemoryFakeAlwaysReadZero, 100, 200));
+  ASSERT_FALSE(overflow->Read(UINT64_MAX - 10, buffer.data(), 100));
 }