odsign: Refactor into binary + library

Create libsigningutils library which contains functionality for
signing, signature verification, and fsverity. The goal is to allow
init to use some of this functionality during early boot.

Add a unit test to verify extractPublicKeyFromX509() and
verifySignature().

Bug: 199914227
Test: atest
Change-Id: Iea46539302df240cd2c92b1c4f313da773d8d180

6 files changed, 134 insertions, 0 deletions

diff --git a/ondevice-signing/tests/Android.bp b/ondevice-signing/tests/Android.bp
new file mode 100644
index 00000000..9769ca87
--- /dev/null
+++ b/ondevice-signing/tests/Android.bp
@@ -0,0 +1,35 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+cc_test {
+  name: "libsigningutils_test",
+  srcs: ["SigningUtilsTest.cpp"],
+  test_suites: ["device-tests"],
+  compile_multilib: "both",
+  defaults: [
+    "odsign_flags_defaults",
+  ],
+  static_libs: [
+    "libsigningutils",
+  ],
+  shared_libs: [
+    "libbase",
+    "libcrypto",
+  ],
+  data: [
+    "test_file",
+    "test_file.sig",
+    "SigningUtils.cert.der",
+  ],
+}
diff --git a/ondevice-signing/tests/SigningUtils.cert.der b/ondevice-signing/tests/SigningUtils.cert.der
new file mode 100644
index 00000000..0703d596
--- /dev/null
+++ b/ondevice-signing/tests/SigningUtils.cert.der
diff --git a/ondevice-signing/tests/SigningUtils.pem b/ondevice-signing/tests/SigningUtils.pem
new file mode 100644
index 00000000..01dfa5ed
--- /dev/null
+++ b/ondevice-signing/tests/SigningUtils.pem
@@ -0,0 +1,51 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIJKAIBAAKCAgEAwyOUvcTpPuPxw2I9E28uhXT9pbJAgNE0dc1emOWRfapZ5iow
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+Iz3zcytrZZbAuOjCnhxNL/6XgcttqWSVFB4Ul1xiXrXDx2Xq+FfM40UF7oKGd+Kt
+B0wMqoZJj+0CdFfRZxHA6/n8v1Al+8lYo8smp+R9fR6qZKcugEFgdVkIl7E=
+-----END RSA PRIVATE KEY-----
diff --git a/ondevice-signing/tests/SigningUtilsTest.cpp b/ondevice-signing/tests/SigningUtilsTest.cpp
new file mode 100644
index 00000000..10f7629e
--- /dev/null
+++ b/ondevice-signing/tests/SigningUtilsTest.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android-base/file.h>
+#include <gtest/gtest.h>
+
+#include "CertUtils.h"
+#include "VerityUtils.h"
+
+// These files were created using the following commands:
+// openssl genrsa -out SigningUtils.pem 4096
+// openssl req -new -x509 -key SigningUtils.pem -out SigningUtils.cert.pem
+// openssl x509 -in SigningUtils.cert.pem -out SigningUtils.cert.der -outform DER
+// head -c 4096 </dev/urandom >test_file
+// openssl dgst -sign SigningUtils.pem -keyform PEM -sha256 -out test_file.sig -binary test_file
+const std::string kTestCert = "SigningUtils.cert.der";
+const std::string kTestFile = "test_file";
+const std::string kTestFileSignature = "test_file.sig";
+
+TEST(SigningUtilsTest, CheckVerifySignature) {
+    std::string signature;
+    std::string sigFile = android::base::GetExecutableDirectory() + "/" + kTestFileSignature;
+    ASSERT_TRUE(android::base::ReadFileToString(sigFile, &signature));
+
+    std::string data;
+    std::string testFile = android::base::GetExecutableDirectory() + "/" + kTestFile;
+    ASSERT_TRUE(android::base::ReadFileToString(testFile, &data));
+
+    std::string testCert = android::base::GetExecutableDirectory() + "/" + kTestCert;
+    auto trustedKey = extractPublicKeyFromX509(testCert.c_str());
+    ASSERT_TRUE(trustedKey.ok());
+
+    auto result = verifySignature(data, signature, *trustedKey);
+    ASSERT_TRUE(result.ok());
+}
diff --git a/ondevice-signing/tests/test_file b/ondevice-signing/tests/test_file
new file mode 100644
index 00000000..8a121bea
--- /dev/null
+++ b/ondevice-signing/tests/test_file
diff --git a/ondevice-signing/tests/test_file.sig b/ondevice-signing/tests/test_file.sig
new file mode 100644
index 00000000..ffd95dcd
--- /dev/null
+++ b/ondevice-signing/tests/test_file.sig