KeyMint VTS: local asymmetric verification

Change verification of ECDSA and RSA signatures so it happens locally
in the test, rather than by invoking a VERIFY operation against KeyMint.

Test: VtsAidlKeyMintTargetTest
Change-Id: I0efc30f3c96cd70ac636d34718eff53cc23f1480
diff --git a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
index 4789204..1a05ac8 100644
--- a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
@@ -59,6 +59,11 @@
 namespace test {
 
 namespace {
+
+// Overhead for PKCS#1 v1.5 signature padding of undigested messages.  Digested messages have
+// additional overhead, for the digest algorithmIdentifier required by PKCS#1.
+const size_t kPkcs1UndigestedSignaturePaddingOverhead = 11;
+
 typedef KeyMintAidlTestBase::KeyData KeyData;
 // Predicate for testing basic characteristics validity in generation or import.
 bool KeyCharacteristicsBasicallyValid(SecurityLevel secLevel,
@@ -590,6 +595,110 @@
     VerifyMessage(key_blob_, message, signature, params);
 }
 
+void KeyMintAidlTestBase::LocalVerifyMessage(const string& message, const string& signature,
+                                             const AuthorizationSet& params) {
+    SCOPED_TRACE("LocalVerifyMessage");
+
+    // Retrieve the public key from the leaf certificate.
+    ASSERT_GT(cert_chain_.size(), 0);
+    X509_Ptr key_cert(parse_cert_blob(cert_chain_[0].encodedCertificate));
+    ASSERT_TRUE(key_cert.get());
+    EVP_PKEY_Ptr pub_key(X509_get_pubkey(key_cert.get()));
+    ASSERT_TRUE(pub_key.get());
+
+    Digest digest = params.GetTagValue(TAG_DIGEST).value();
+    PaddingMode padding = PaddingMode::NONE;
+    auto tag = params.GetTagValue(TAG_PADDING);
+    if (tag.has_value()) {
+        padding = tag.value();
+    }
+
+    if (digest == Digest::NONE) {
+        switch (EVP_PKEY_id(pub_key.get())) {
+            case EVP_PKEY_EC: {
+                vector<uint8_t> data((EVP_PKEY_bits(pub_key.get()) + 7) / 8);
+                size_t data_size = std::min(data.size(), message.size());
+                memcpy(data.data(), message.data(), data_size);
+                EC_KEY_Ptr ecdsa(EVP_PKEY_get1_EC_KEY(pub_key.get()));
+                ASSERT_TRUE(ecdsa.get());
+                ASSERT_EQ(1,
+                          ECDSA_verify(0, reinterpret_cast<const uint8_t*>(data.data()), data_size,
+                                       reinterpret_cast<const uint8_t*>(signature.data()),
+                                       signature.size(), ecdsa.get()));
+                break;
+            }
+            case EVP_PKEY_RSA: {
+                vector<uint8_t> data(EVP_PKEY_size(pub_key.get()));
+                size_t data_size = std::min(data.size(), message.size());
+                memcpy(data.data(), message.data(), data_size);
+
+                RSA_Ptr rsa(EVP_PKEY_get1_RSA(const_cast<EVP_PKEY*>(pub_key.get())));
+                ASSERT_TRUE(rsa.get());
+
+                size_t key_len = RSA_size(rsa.get());
+                int openssl_padding = RSA_NO_PADDING;
+                switch (padding) {
+                    case PaddingMode::NONE:
+                        ASSERT_TRUE(data_size <= key_len);
+                        ASSERT_EQ(key_len, signature.size());
+                        openssl_padding = RSA_NO_PADDING;
+                        break;
+                    case PaddingMode::RSA_PKCS1_1_5_SIGN:
+                        ASSERT_TRUE(data_size + kPkcs1UndigestedSignaturePaddingOverhead <=
+                                    key_len);
+                        openssl_padding = RSA_PKCS1_PADDING;
+                        break;
+                    default:
+                        ADD_FAILURE() << "Unsupported RSA padding mode " << padding;
+                }
+
+                vector<uint8_t> decrypted_data(key_len);
+                int bytes_decrypted = RSA_public_decrypt(
+                        signature.size(), reinterpret_cast<const uint8_t*>(signature.data()),
+                        decrypted_data.data(), rsa.get(), openssl_padding);
+                ASSERT_GE(bytes_decrypted, 0);
+
+                const uint8_t* compare_pos = decrypted_data.data();
+                size_t bytes_to_compare = bytes_decrypted;
+                uint8_t zero_check_result = 0;
+                if (padding == PaddingMode::NONE && data_size < bytes_to_compare) {
+                    // If the data is short, for "unpadded" signing we zero-pad to the left.  So
+                    // during verification we should have zeros on the left of the decrypted data.
+                    // Do a constant-time check.
+                    const uint8_t* zero_end = compare_pos + bytes_to_compare - data_size;
+                    while (compare_pos < zero_end) zero_check_result |= *compare_pos++;
+                    ASSERT_EQ(0, zero_check_result);
+                    bytes_to_compare = data_size;
+                }
+                ASSERT_EQ(0, memcmp(compare_pos, data.data(), bytes_to_compare));
+                break;
+            }
+            default:
+                ADD_FAILURE() << "Unknown public key type";
+        }
+    } else {
+        EVP_MD_CTX digest_ctx;
+        EVP_MD_CTX_init(&digest_ctx);
+        EVP_PKEY_CTX* pkey_ctx;
+        const EVP_MD* md = openssl_digest(digest);
+        ASSERT_NE(md, nullptr);
+        ASSERT_EQ(1, EVP_DigestVerifyInit(&digest_ctx, &pkey_ctx, md, nullptr, pub_key.get()));
+
+        if (padding == PaddingMode::RSA_PSS) {
+            EXPECT_GT(EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING), 0);
+            EXPECT_GT(EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, EVP_MD_size(md)), 0);
+        }
+
+        ASSERT_EQ(1, EVP_DigestVerifyUpdate(&digest_ctx,
+                                            reinterpret_cast<const uint8_t*>(message.data()),
+                                            message.size()));
+        ASSERT_EQ(1, EVP_DigestVerifyFinal(&digest_ctx,
+                                           reinterpret_cast<const uint8_t*>(signature.data()),
+                                           signature.size()));
+        EVP_MD_CTX_cleanup(&digest_ctx);
+    }
+}
+
 string KeyMintAidlTestBase::EncryptMessage(const vector<uint8_t>& key_blob, const string& message,
                                            const AuthorizationSet& in_params,
                                            AuthorizationSet* out_params) {
diff --git a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.h b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.h
index cb38938..1a14d47 100644
--- a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.h
+++ b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.h
@@ -162,6 +162,8 @@
                        const string& signature, const AuthorizationSet& params);
     void VerifyMessage(const string& message, const string& signature,
                        const AuthorizationSet& params);
+    void LocalVerifyMessage(const string& message, const string& signature,
+                            const AuthorizationSet& params);
 
     string EncryptMessage(const vector<uint8_t>& key_blob, const string& message,
                           const AuthorizationSet& in_params, AuthorizationSet* out_params);
diff --git a/security/keymint/aidl/vts/functional/KeyMintTest.cpp b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
index cd7d603..2c0c459 100644
--- a/security/keymint/aidl/vts/functional/KeyMintTest.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
@@ -482,7 +482,6 @@
     void CheckBaseParams(const vector<KeyCharacteristics>& keyCharacteristics) {
         AuthorizationSet auths = CheckCommonParams(keyCharacteristics);
         EXPECT_TRUE(auths.Contains(TAG_PURPOSE, KeyPurpose::SIGN));
-        EXPECT_TRUE(auths.Contains(TAG_PURPOSE, KeyPurpose::VERIFY));
 
         // Check that some unexpected tags/values are NOT present.
         EXPECT_FALSE(auths.Contains(TAG_PURPOSE, KeyPurpose::ENCRYPT));
@@ -495,7 +494,6 @@
         EXPECT_TRUE(auths.Contains(TAG_PURPOSE, KeyPurpose::DECRYPT));
 
         EXPECT_FALSE(auths.Contains(TAG_PURPOSE, KeyPurpose::SIGN));
-        EXPECT_FALSE(auths.Contains(TAG_PURPOSE, KeyPurpose::VERIFY));
     }
 
     AuthorizationSet CheckCommonParams(const vector<KeyCharacteristics>& keyCharacteristics) {
@@ -1986,6 +1984,50 @@
     string message = "12345678901234567890123456789012";
     string signature = SignMessage(
             message, AuthorizationSetBuilder().Digest(Digest::NONE).Padding(PaddingMode::NONE));
+    LocalVerifyMessage(message, signature,
+                       AuthorizationSetBuilder().Digest(Digest::NONE).Padding(PaddingMode::NONE));
+}
+
+/*
+ * SigningOperationsTest.RsaAllPaddingsAndDigests
+ *
+ * Verifies RSA signature/verification for all padding modes and digests.
+ */
+TEST_P(SigningOperationsTest, RsaAllPaddingsAndDigests) {
+    auto authorizations = AuthorizationSetBuilder()
+                                  .Authorization(TAG_NO_AUTH_REQUIRED)
+                                  .RsaSigningKey(2048, 65537)
+                                  .Digest(ValidDigests(true /* withNone */, true /* withMD5 */))
+                                  .Padding(PaddingMode::NONE)
+                                  .Padding(PaddingMode::RSA_PSS)
+                                  .Padding(PaddingMode::RSA_PKCS1_1_5_SIGN)
+                                  .SetDefaultValidity();
+
+    ASSERT_EQ(ErrorCode::OK, GenerateKey(authorizations));
+
+    string message(128, 'a');
+    string corrupt_message(message);
+    ++corrupt_message[corrupt_message.size() / 2];
+
+    for (auto padding :
+         {PaddingMode::NONE, PaddingMode::RSA_PSS, PaddingMode::RSA_PKCS1_1_5_SIGN}) {
+        for (auto digest : ValidDigests(true /* withNone */, true /* withMD5 */)) {
+            if (padding == PaddingMode::NONE && digest != Digest::NONE) {
+                // Digesting only makes sense with padding.
+                continue;
+            }
+
+            if (padding == PaddingMode::RSA_PSS && digest == Digest::NONE) {
+                // PSS requires digesting.
+                continue;
+            }
+
+            string signature =
+                    SignMessage(message, AuthorizationSetBuilder().Digest(digest).Padding(padding));
+            LocalVerifyMessage(message, signature,
+                               AuthorizationSetBuilder().Digest(digest).Padding(padding));
+        }
+    }
 }
 
 /*
@@ -2432,6 +2474,39 @@
 }
 
 /*
+ * SigningOperationsTest.EcdsaAllDigestsAndCurves
+ *
+ * Verifies ECDSA signature/verification for all digests and curves.
+ */
+TEST_P(SigningOperationsTest, EcdsaAllDigestsAndCurves) {
+    auto digests = ValidDigests(true /* withNone */, false /* withMD5 */);
+
+    string message = "1234567890";
+    string corrupt_message = "2234567890";
+    for (auto curve : ValidCurves()) {
+        SCOPED_TRACE(testing::Message() << "Curve::" << curve);
+        ErrorCode error = GenerateKey(AuthorizationSetBuilder()
+                                              .Authorization(TAG_NO_AUTH_REQUIRED)
+                                              .EcdsaSigningKey(curve)
+                                              .Digest(digests)
+                                              .SetDefaultValidity());
+        EXPECT_EQ(ErrorCode::OK, error) << "Failed to generate key for EC curve " << curve;
+        if (error != ErrorCode::OK) {
+            continue;
+        }
+
+        for (auto digest : digests) {
+            SCOPED_TRACE(testing::Message() << "Digest::" << digest);
+            string signature = SignMessage(message, AuthorizationSetBuilder().Digest(digest));
+            LocalVerifyMessage(message, signature, AuthorizationSetBuilder().Digest(digest));
+        }
+
+        auto rc = DeleteKey();
+        ASSERT_TRUE(rc == ErrorCode::OK || rc == ErrorCode::UNIMPLEMENTED);
+    }
+}
+
+/*
  * SigningOperationsTest.EcdsaAllCurves
  *
  * Verifies that ECDSA operations succeed with all possible curves.
@@ -2699,207 +2774,6 @@
 typedef KeyMintAidlTestBase VerificationOperationsTest;
 
 /*
- * VerificationOperationsTest.RsaSuccess
- *
- * Verifies that a simple RSA signature/verification sequence succeeds.
- */
-TEST_P(VerificationOperationsTest, RsaSuccess) {
-    ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
-                                                 .Authorization(TAG_NO_AUTH_REQUIRED)
-                                                 .RsaSigningKey(2048, 65537)
-                                                 .Digest(Digest::NONE)
-                                                 .Padding(PaddingMode::NONE)
-                                                 .SetDefaultValidity()));
-    string message = "12345678901234567890123456789012";
-    string signature = SignMessage(
-            message, AuthorizationSetBuilder().Digest(Digest::NONE).Padding(PaddingMode::NONE));
-    VerifyMessage(message, signature,
-                  AuthorizationSetBuilder().Digest(Digest::NONE).Padding(PaddingMode::NONE));
-}
-
-/*
- * VerificationOperationsTest.RsaAllPaddingsAndDigests
- *
- * Verifies RSA signature/verification for all padding modes and digests.
- */
-TEST_P(VerificationOperationsTest, RsaAllPaddingsAndDigests) {
-    auto authorizations = AuthorizationSetBuilder()
-                                  .Authorization(TAG_NO_AUTH_REQUIRED)
-                                  .RsaSigningKey(2048, 65537)
-                                  .Digest(ValidDigests(true /* withNone */, true /* withMD5 */))
-                                  .Padding(PaddingMode::NONE)
-                                  .Padding(PaddingMode::RSA_PSS)
-                                  .Padding(PaddingMode::RSA_PKCS1_1_5_SIGN)
-                                  .SetDefaultValidity();
-
-    ASSERT_EQ(ErrorCode::OK, GenerateKey(authorizations));
-
-    string message(128, 'a');
-    string corrupt_message(message);
-    ++corrupt_message[corrupt_message.size() / 2];
-
-    for (auto padding :
-         {PaddingMode::NONE, PaddingMode::RSA_PSS, PaddingMode::RSA_PKCS1_1_5_SIGN}) {
-        for (auto digest : ValidDigests(true /* withNone */, true /* withMD5 */)) {
-            if (padding == PaddingMode::NONE && digest != Digest::NONE) {
-                // Digesting only makes sense with padding.
-                continue;
-            }
-
-            if (padding == PaddingMode::RSA_PSS && digest == Digest::NONE) {
-                // PSS requires digesting.
-                continue;
-            }
-
-            string signature =
-                    SignMessage(message, AuthorizationSetBuilder().Digest(digest).Padding(padding));
-            VerifyMessage(message, signature,
-                          AuthorizationSetBuilder().Digest(digest).Padding(padding));
-
-            /* TODO(seleneh) add exportkey tests back later when we have decided on
-             * the new api.
-                        if (digest != Digest::NONE) {
-                            // Verify with OpenSSL.
-                            vector<uint8_t> pubkey;
-                            ASSERT_EQ(ErrorCode::OK, ExportKey(KeyFormat::X509, &pubkey));
-
-                            const uint8_t* p = pubkey.data();
-                            EVP_PKEY_Ptr pkey(d2i_PUBKEY(nullptr, &p, pubkey.size()));
-                            ASSERT_TRUE(pkey.get());
-
-                            EVP_MD_CTX digest_ctx;
-                            EVP_MD_CTX_init(&digest_ctx);
-                            EVP_PKEY_CTX* pkey_ctx;
-                            const EVP_MD* md = openssl_digest(digest);
-                            ASSERT_NE(md, nullptr);
-                            EXPECT_EQ(1, EVP_DigestVerifyInit(&digest_ctx, &pkey_ctx, md,
-             nullptr, pkey.get()));
-
-                            switch (padding) {
-                                case PaddingMode::RSA_PSS:
-                                    EXPECT_GT(EVP_PKEY_CTX_set_rsa_padding(pkey_ctx,
-               RSA_PKCS1_PSS_PADDING), 0); EXPECT_GT(EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx,
-               EVP_MD_size(md)), 0); break; case PaddingMode::RSA_PKCS1_1_5_SIGN:
-                                    // PKCS1 is the default; don't need to set anything.
-                                    break;
-                                default:
-                                    FAIL();
-                                    break;
-                            }
-
-                            EXPECT_EQ(1, EVP_DigestVerifyUpdate(&digest_ctx, message.data(),
-               message.size())); EXPECT_EQ(1, EVP_DigestVerifyFinal(&digest_ctx,
-                                                            reinterpret_cast<const
-               uint8_t*>(signature.data()), signature.size())); EVP_MD_CTX_cleanup(&digest_ctx);
-                        }
-            */
-
-            // Corrupt signature shouldn't verify.
-            string corrupt_signature(signature);
-            ++corrupt_signature[corrupt_signature.size() / 2];
-
-            EXPECT_EQ(ErrorCode::OK,
-                      Begin(KeyPurpose::VERIFY,
-                            AuthorizationSetBuilder().Digest(digest).Padding(padding)));
-            string result;
-            EXPECT_EQ(ErrorCode::VERIFICATION_FAILED, Finish(message, corrupt_signature, &result));
-
-            // Corrupt message shouldn't verify
-            EXPECT_EQ(ErrorCode::OK,
-                      Begin(KeyPurpose::VERIFY,
-                            AuthorizationSetBuilder().Digest(digest).Padding(padding)));
-            EXPECT_EQ(ErrorCode::VERIFICATION_FAILED, Finish(corrupt_message, signature, &result));
-        }
-    }
-}
-
-/*
- * VerificationOperationsTest.RsaAllDigestsAndCurves
- *
- * Verifies ECDSA signature/verification for all digests and curves.
- */
-TEST_P(VerificationOperationsTest, EcdsaAllDigestsAndCurves) {
-    auto digests = ValidDigests(true /* withNone */, false /* withMD5 */);
-
-    string message = "1234567890";
-    string corrupt_message = "2234567890";
-    for (auto curve : ValidCurves()) {
-        ErrorCode error = GenerateKey(AuthorizationSetBuilder()
-                                              .Authorization(TAG_NO_AUTH_REQUIRED)
-                                              .EcdsaSigningKey(curve)
-                                              .Digest(digests)
-                                              .SetDefaultValidity());
-        EXPECT_EQ(ErrorCode::OK, error) << "Failed to generate key for EC curve " << curve;
-        if (error != ErrorCode::OK) {
-            continue;
-        }
-
-        for (auto digest : digests) {
-            string signature = SignMessage(message, AuthorizationSetBuilder().Digest(digest));
-            VerifyMessage(message, signature, AuthorizationSetBuilder().Digest(digest));
-
-            /* TODO(seleneh) add exportkey tests back later when we have decided on
-             * the new api.
-
-                        // Verify with OpenSSL
-                        if (digest != Digest::NONE) {
-                            vector<uint8_t> pubkey;
-                            ASSERT_EQ(ErrorCode::OK, ExportKey(KeyFormat::X509, &pubkey))
-                                    << curve << ' ' << digest;
-
-                            const uint8_t* p = pubkey.data();
-                            EVP_PKEY_Ptr pkey(d2i_PUBKEY(nullptr, &p, pubkey.size()));
-                            ASSERT_TRUE(pkey.get());
-
-                            EVP_MD_CTX digest_ctx;
-                            EVP_MD_CTX_init(&digest_ctx);
-                            EVP_PKEY_CTX* pkey_ctx;
-                            const EVP_MD* md = openssl_digest(digest);
-
-                            EXPECT_EQ(1, EVP_DigestVerifyInit(&digest_ctx, &pkey_ctx, md,
-             nullptr, pkey.get()))
-                                    << curve << ' ' << digest;
-
-                            EXPECT_EQ(1, EVP_DigestVerifyUpdate(&digest_ctx, message.data(),
-               message.size()))
-                                    << curve << ' ' << digest;
-
-                            EXPECT_EQ(1,
-                                      EVP_DigestVerifyFinal(&digest_ctx,
-                                                            reinterpret_cast<const
-               uint8_t*>(signature.data()), signature.size()))
-                                    << curve << ' ' << digest;
-
-                            EVP_MD_CTX_cleanup(&digest_ctx);
-                        }
-            */
-            // Corrupt signature shouldn't verify.
-            string corrupt_signature(signature);
-            ++corrupt_signature[corrupt_signature.size() / 2];
-
-            EXPECT_EQ(ErrorCode::OK,
-                      Begin(KeyPurpose::VERIFY, AuthorizationSetBuilder().Digest(digest)))
-                    << curve << ' ' << digest;
-
-            string result;
-            EXPECT_EQ(ErrorCode::VERIFICATION_FAILED, Finish(message, corrupt_signature, &result))
-                    << curve << ' ' << digest;
-
-            // Corrupt message shouldn't verify
-            EXPECT_EQ(ErrorCode::OK,
-                      Begin(KeyPurpose::VERIFY, AuthorizationSetBuilder().Digest(digest)))
-                    << curve << ' ' << digest;
-
-            EXPECT_EQ(ErrorCode::VERIFICATION_FAILED, Finish(corrupt_message, signature, &result))
-                    << curve << ' ' << digest;
-        }
-
-        auto rc = DeleteKey();
-        ASSERT_TRUE(rc == ErrorCode::OK || rc == ErrorCode::UNIMPLEMENTED);
-    }
-}
-
-/*
  * VerificationOperationsTest.HmacSigningKeyCannotVerify
  *
  * Verifies HMAC signing and verification, but that a signing key cannot be used to verify.
@@ -3016,7 +2890,7 @@
     string message(1024 / 8, 'a');
     auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256).Padding(PaddingMode::RSA_PSS);
     string signature = SignMessage(message, params);
-    VerifyMessage(message, signature, params);
+    LocalVerifyMessage(message, signature, params);
 }
 
 /*
@@ -3058,7 +2932,7 @@
     string message(1024 / 8, 'a');
     auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256).Padding(PaddingMode::RSA_PSS);
     string signature = SignMessage(message, params);
-    VerifyMessage(message, signature, params);
+    LocalVerifyMessage(message, signature, params);
 }
 
 /*
@@ -3116,7 +2990,7 @@
     string message(32, 'a');
     auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256);
     string signature = SignMessage(message, params);
-    VerifyMessage(message, signature, params);
+    LocalVerifyMessage(message, signature, params);
 }
 
 /*
@@ -3143,7 +3017,7 @@
     string message(32, 'a');
     auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256);
     string signature = SignMessage(message, params);
-    VerifyMessage(message, signature, params);
+    LocalVerifyMessage(message, signature, params);
 }
 
 /*
@@ -3169,7 +3043,7 @@
     string message(32, 'a');
     auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256);
     string signature = SignMessage(message, params);
-    VerifyMessage(message, signature, params);
+    LocalVerifyMessage(message, signature, params);
 }
 
 /*
@@ -3195,7 +3069,7 @@
     string message(32, 'a');
     auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256);
     string signature = SignMessage(message, params);
-    VerifyMessage(message, signature, params);
+    LocalVerifyMessage(message, signature, params);
 }
 
 /*