AU: detect failure when using public key verification

delta_performer.cc

Index: delta_performer.cc
diff --git a/delta_performer.cc b/delta_performer.cc
index 54a69fb132f234dbb57088df09086ba8b64a4ca8..f973bc7d7a5bc3cd2dc997f6aeba73874cb0b0f4 100644
--- a/delta_performer.cc
+++ b/delta_performer.cc
@@ -572,7 +572,8 @@ bool DeltaPerformer::ExtractSignatureMessage(
 bool DeltaPerformer::VerifyPayload(
     const string& public_key_path,
     const std::string& update_check_response_hash,
-    const uint64_t update_check_response_size) {
+    const uint64_t update_check_response_size,
+    bool* signature_failed) {
   string key_path = public_key_path;
   if (key_path.empty()) {
     key_path = kUpdatePayloadPublicKeyPath;
@@ -604,7 +605,16 @@ bool DeltaPerformer::VerifyPayload(
   vector<char> hash_data = signed_hasher.raw_hash();
   PayloadSigner::PadRSA2048SHA256Hash(&hash_data);
   TEST_AND_RETURN_FALSE(!hash_data.empty());
-  TEST_AND_RETURN_FALSE(hash_data == signed_hash_data);
+  if (hash_data != signed_hash_data) {
+    LOG(ERROR) << "Public key verificaion failed. This is non-fatal. "
+        "Attached Signature:";
+    utils::HexDumpVector(signed_hash_data);
+    LOG(ERROR) << "Computed Signature:";
+    utils::HexDumpVector(hash_data);
+    if (signature_failed) {
+      *signature_failed = true;
+    }
+  }
   return true;
 }