commit 4568f4bc0f116f097a13b1d931de93cf525ae204
author Christopher Ferris <cferris@google.com> Tue Oct 23 17:42:41 2018 -0700
committer Christopher Ferris <cferris@google.com> Mon Oct 29 18:08:09 2018 -0700
tree 2832d853a8b2dfa6f66f1c5d04d22df742b22d4d
parent 2a8460721ca219ea2d9bc00e0412297afd12df47

Verify that the elf matches the expected arch.

To avoid a case where a malicious app might try and trick the system to
create an elf and register object that mismatches, always verify that they
are the same arch.

Test: Ran unit tests.
Change-Id: I66978e9e02f8e4f396856912e7019528ead4838e

libunwindstack/tests/JitDebugTest.cpp

diff --git a/libunwindstack/tests/JitDebugTest.cpp b/libunwindstack/tests/JitDebugTest.cpp
index 4598526..b1ca111 100644
--- a/libunwindstack/tests/JitDebugTest.cpp
+++ b/libunwindstack/tests/JitDebugTest.cpp
@@ -35,12 +35,19 @@
 
 class JitDebugTest : public ::testing::Test {
  protected:
-  void SetUp() override {
-    memory_ = new MemoryFake;
-    process_memory_.reset(memory_);
+  void CreateFakeElf(MapInfo* map_info) {
+    MemoryFake* memory = new MemoryFake;
+    ElfFake* elf = new ElfFake(memory);
+    elf->FakeSetValid(true);
+    ElfInterfaceFake* interface = new ElfInterfaceFake(memory);
+    elf->FakeSetInterface(interface);
+    interface->FakeSetGlobalVariable("__jit_debug_descriptor", 0x800);
+    map_info->elf.reset(elf);
+  }
 
+  void Init(ArchEnum arch) {
     jit_debug_.reset(new JitDebug(process_memory_));
-    jit_debug_->SetArch(ARCH_ARM);
+    jit_debug_->SetArch(arch);
 
     maps_.reset(
         new BufferMaps("1000-4000 ---s 00000000 00:00 0 /fake/elf1\n"
@@ -57,33 +64,22 @@
 
     MapInfo* map_info = maps_->Get(3);
     ASSERT_TRUE(map_info != nullptr);
-    MemoryFake* memory = new MemoryFake;
-    ElfFake* elf = new ElfFake(memory);
-    elf->FakeSetValid(true);
-    ElfInterfaceFake* interface = new ElfInterfaceFake(memory);
-    elf->FakeSetInterface(interface);
-    interface->FakeSetGlobalVariable("__jit_debug_descriptor", 0x800);
-    map_info->elf.reset(elf);
+    CreateFakeElf(map_info);
 
     map_info = maps_->Get(5);
     ASSERT_TRUE(map_info != nullptr);
-    memory = new MemoryFake;
-    elf = new ElfFake(memory);
-    elf->FakeSetValid(true);
-    interface = new ElfInterfaceFake(memory);
-    elf->FakeSetInterface(interface);
-    interface->FakeSetGlobalVariable("__jit_debug_descriptor", 0x800);
-    map_info->elf.reset(elf);
+    CreateFakeElf(map_info);
 
     map_info = maps_->Get(7);
     ASSERT_TRUE(map_info != nullptr);
-    memory = new MemoryFake;
-    elf = new ElfFake(memory);
-    elf->FakeSetValid(true);
-    interface = new ElfInterfaceFake(memory);
-    elf->FakeSetInterface(interface);
-    interface->FakeSetGlobalVariable("__jit_debug_descriptor", 0x800);
-    map_info->elf.reset(elf);
+    CreateFakeElf(map_info);
+  }
+
+  void SetUp() override {
+    memory_ = new MemoryFake;
+    process_memory_.reset(memory_);
+
+    Init(ARCH_ARM);
   }
 
   template <typename EhdrType, typename ShdrType>
@@ -326,6 +322,8 @@
 }
 
 TEST_F(JitDebugTest, get_elf_x86) {
+  Init(ARCH_X86);
+
   CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
 
   WriteDescriptor32(0xf800, 0x200000);
@@ -343,12 +341,13 @@
 }
 
 TEST_F(JitDebugTest, get_elf_64) {
+  Init(ARCH_ARM64);
+
   CreateElf<Elf64_Ehdr, Elf64_Shdr>(0x4000, ELFCLASS64, EM_AARCH64, 0x1500, 0x200);
 
   WriteDescriptor64(0xf800, 0x200000);
   WriteEntry64(0x200000, 0, 0, 0x4000, 0x1000);
 
-  jit_debug_->SetArch(ARCH_ARM64);
   Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
   ASSERT_TRUE(elf != nullptr);