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/MapInfo.cpp

diff --git a/libunwindstack/MapInfo.cpp b/libunwindstack/MapInfo.cpp
index 8527797..fe32b5e 100644
--- a/libunwindstack/MapInfo.cpp
+++ b/libunwindstack/MapInfo.cpp
@@ -146,7 +146,7 @@
   return nullptr;
 }
 
-Elf* MapInfo::GetElf(const std::shared_ptr<Memory>& process_memory) {
+Elf* MapInfo::GetElf(const std::shared_ptr<Memory>& process_memory, ArchEnum expected_arch) {
   // Make sure no other thread is trying to add the elf to this map.
   std::lock_guard<std::mutex> guard(mutex_);
 
@@ -176,6 +176,10 @@
   // If the init fails, keep the elf around as an invalid object so we
   // don't try to reinit the object.
   elf->Init();
+  if (elf->valid() && expected_arch != elf->arch()) {
+    // Make the elf invalid, mismatch between arch and expected arch.
+    elf->Invalidate();
+  }
 
   if (locked) {
     Elf::CacheAdd(this);