AU: Support signed payload verification through the delta generator.

generate_delta_main.cc

Index: generate_delta_main.cc
diff --git a/generate_delta_main.cc b/generate_delta_main.cc
index 9fc7fd7786d9c0117f485c0cde9148a9137ac363..0f791e0b509dfb6cbbb16ead976e394df4789fdc 100644
--- a/generate_delta_main.cc
+++ b/generate_delta_main.cc
@@ -40,6 +40,7 @@ DEFINE_string(in_file, "",
 DEFINE_string(out_file, "", "Path to output delta payload file");
 DEFINE_string(out_hash_file, "", "Path to output hash file");
 DEFINE_string(private_key, "", "Path to private key in .pem format");
+DEFINE_string(public_key, "", "Path to public key in .pem format");
 DEFINE_string(prefs_dir, "/tmp/update_engine_prefs",
               "Preferences directory, used with apply_delta");
 DEFINE_int32(signature_size, 0, "Raw signature size used for hash calculation");
@@ -94,6 +95,16 @@ void SignPayload() {
   LOG(INFO) << "Done signing payload.";
 }
 
+void VerifySignedPayload() {
+  LOG(INFO) << "Verifying signed payload.";
+  LOG_IF(FATAL, FLAGS_in_file.empty())
+      << "Must pass --in_file to verify signed payload.";
+  LOG_IF(FATAL, FLAGS_public_key.empty())
+      << "Must pass --public_key to verify signed payload.";
+  CHECK(PayloadSigner::VerifySignedPayload(FLAGS_in_file, FLAGS_public_key));
+  LOG(INFO) << "Done verifying signed payload.";
+}
+
 void ApplyDelta() {
   LOG(INFO) << "Applying delta.";
   LOG_IF(FATAL, FLAGS_old_image.empty())
@@ -154,6 +165,10 @@ int Main(int argc, char** argv) {
     SignPayload();
     return 0;
   }
+  if (!FLAGS_public_key.empty()) {
+    VerifySignedPayload();
+    return 0;
+  }
   if (!FLAGS_in_file.empty()) {
     ApplyDelta();
     return 0;