Test for malformed modulus in attestation cert

With this patch the attestation tests use the attested to key to sign a
message and use the public key in the attestation certificate to verify
the signature. Thereby tripping up over malformed public keys.

Bug: 118372436
Test: VtsHalKeymasterV4_0TargetTest
Change-Id: I4ce75c689cd5b6bb04a56e283c1202501ee821c9
diff --git a/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp b/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
index 784ae30..a9c6f6c 100644
--- a/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
+++ b/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
@@ -181,7 +181,35 @@
     return d2i_X509(nullptr, &p, blob.size());
 }
 
-bool verify_chain(const hidl_vec<hidl_vec<uint8_t>>& chain) {
+bool verify_chain(const hidl_vec<hidl_vec<uint8_t>>& chain, const std::string& msg,
+                  const std::string& signature) {
+    {
+        EVP_MD_CTX md_ctx_verify;
+        X509_Ptr signing_cert(parse_cert_blob(chain[0]));
+        EVP_PKEY_Ptr signing_pubkey(X509_get_pubkey(signing_cert.get()));
+        EXPECT_TRUE(signing_pubkey);
+        ERR_print_errors_cb(
+            [](const char* str, size_t len, void* ctx) -> int {
+                (void)ctx;
+                std::cerr << std::string(str, len) << std::endl;
+                return 1;
+            },
+            nullptr);
+
+        EVP_MD_CTX_init(&md_ctx_verify);
+
+        bool result = false;
+        EXPECT_TRUE((result = EVP_DigestVerifyInit(&md_ctx_verify, NULL, EVP_sha256(), NULL,
+                                                   signing_pubkey.get())));
+        EXPECT_TRUE(
+            (result = result && EVP_DigestVerifyUpdate(&md_ctx_verify, msg.c_str(), msg.size())));
+        EXPECT_TRUE((result = result && EVP_DigestVerifyFinal(
+                                            &md_ctx_verify,
+                                            reinterpret_cast<const uint8_t*>(signature.c_str()),
+                                            signature.size())));
+        EVP_MD_CTX_cleanup(&md_ctx_verify);
+        if (!result) return false;
+    }
     for (size_t i = 0; i < chain.size(); ++i) {
         X509_Ptr key_cert(parse_cert_blob(chain[i]));
         X509_Ptr signing_cert;
@@ -3833,8 +3861,8 @@
     ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
                                              .Authorization(TAG_NO_AUTH_REQUIRED)
                                              .RsaSigningKey(2048, 65537)
-                                             .Digest(Digest::NONE)
-                                             .Padding(PaddingMode::NONE)
+                                             .Digest(Digest::SHA_2_256)
+                                             .Padding(PaddingMode::RSA_PKCS1_1_5_SIGN)
                                              .Authorization(TAG_INCLUDE_UNIQUE_ID)));
 
     hidl_vec<hidl_vec<uint8_t>> cert_chain;
@@ -3844,7 +3872,13 @@
                             .Authorization(TAG_ATTESTATION_APPLICATION_ID, HidlBuf("foo")),
                         &cert_chain));
     EXPECT_GE(cert_chain.size(), 2U);
-    EXPECT_TRUE(verify_chain(cert_chain));
+
+    string message = "12345678901234567890123456789012";
+    string signature = SignMessage(message, AuthorizationSetBuilder()
+                                                .Digest(Digest::SHA_2_256)
+                                                .Padding(PaddingMode::RSA_PKCS1_1_5_SIGN));
+
+    EXPECT_TRUE(verify_chain(cert_chain, message, signature));
     EXPECT_TRUE(verify_attestation_record("challenge", "foo",                     //
                                           key_characteristics_.softwareEnforced,  //
                                           key_characteristics_.hardwareEnforced,  //
@@ -3890,7 +3924,11 @@
                             .Authorization(TAG_ATTESTATION_APPLICATION_ID, HidlBuf("foo")),
                         &cert_chain));
     EXPECT_GE(cert_chain.size(), 2U);
-    EXPECT_TRUE(verify_chain(cert_chain));
+
+    string message(1024, 'a');
+    string signature = SignMessage(message, AuthorizationSetBuilder().Digest(Digest::SHA_2_256));
+
+    EXPECT_TRUE(verify_chain(cert_chain, message, signature));
 
     EXPECT_TRUE(verify_attestation_record("challenge", "foo",                     //
                                           key_characteristics_.softwareEnforced,  //