feat: Implement method for checking pKey encryption passphrase

src/main/java/de/mlessmann/certassist/openssl/OpenSSLCertificateCreator.java

@@ -25,6 +25,7 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
 import org.springframework.stereotype.Service;
 import org.springframework.util.CollectionUtils;
 import org.zeroturnaround.exec.ProcessExecutor;
@@ -281,6 +282,43 @@ public class OpenSSLCertificateCreator {
         }
     }
 
+    public boolean isKeyEncrypted(@NonNull Path keyFile) throws InterruptedException, CommandLineOperationException {
+        // If any random passphrase works, the key is not encrypted.
+        return !verifyKeyPassphrase(keyFile, null);
+    }
+
+    /**
+     * Verifies a passphrase against a provided key.
+     * @implNote Due to the implementation of the OpenSSL cli, any password will be valid for unencrypted keys. (Check with {@link #isKeyEncrypted(Path) or by passing {@code null} as the passphrase.)
+     */
+    public boolean verifyKeyPassphrase(@NonNull Path keyFile, @Nullable String passphrase)
+        throws CommandLineOperationException, InterruptedException {
+        // Run OpenSSL command: openssl rsa -check -in <keyFile> -passin pass:<randomKey> -noout and check exit code
+        try {
+            String keyPass = passphrase != null ? passphrase : passwordProvider.generateNewPassword();
+            StartedProcess verifyCommand = new ProcessExecutor()
+                .command(
+                    resolveOpenSSL(),
+                    "rsa",
+                    "-check",
+                    "-in",
+                    keyFile.toString(),
+                    "-passin",
+                    "pass:" + keyPass,
+                    "-noout"
+                )
+                .redirectOutput(Slf4jStream.ofCaller().asError())
+                .redirectError(Slf4jStream.ofCaller().asError())
+                .start();
+            var verifyResult = verifyCommand.getFuture().get();
+            boolean commandSuccess = verifyResult.getExitValue() == 0;
+            log.trace("Key check {} with passphrase provided={}", commandSuccess, passphrase != null);
+            return commandSuccess;
+        } catch (IOException | InterruptedException | ExecutionException e) {
+            throw new CommandLineOperationException("Failed to verify key encryption", e);
+        }
+    }
+
     private Path signCertificate(
         CertificateRequest request,
         Path caCert,

src/test/java/de/mlessmann/certassist/TestOpenSSLCertificateCreator.java

@@ -14,6 +14,8 @@ class TestOpenSSLCertificateCreator {
 
     public static final String TEST_CERT_PASSPHRASE = "ABC-123";
     public static final Path TEST_CERT_PATH = Path.of("src/test/resources/openssl");
+    public static final String ERR_NOT_ENCRYPTED = "Private key not encrypted";
+    public static final String ERR_VERIFY_FAILED = "Certificate verification failed";
     private CertificatePasswordProvider passwordProvider;
 
     @BeforeEach
@@ -50,8 +52,11 @@ class TestOpenSSLCertificateCreator {
 
         try (var cert = certificateCreator.createCertificate(certRequest)) {
             assertThat(certificateCreator.verifyCertificate(cert.certificatePath(), cert.certificatePath()))
-                .isEqualTo(true);
+                .withFailMessage(ERR_VERIFY_FAILED)
-            System.out.println("Certificate created: " + cert);
+                .isTrue();
+            assertThat(certificateCreator.isKeyEncrypted(cert.certificateKeyPath()))
+                .withFailMessage(ERR_NOT_ENCRYPTED)
+                .isTrue();
 
             CertificateRequest childRequest = CertificateRequest
                 .builder()
@@ -73,12 +78,15 @@ class TestOpenSSLCertificateCreator {
             doNothing().when(spiedCert).close();
             when(certificateProvider.requestCertificateUsage(cert.fingerprint())).thenReturn(spiedCert);
             try (var childCert = certificateCreator.createCertificate(childRequest)) {
-                System.out.println("Child certificate created: " + childCert);
                 Path fullchain = childCert.fullchainPath();
                 assertThat(
-                    certificateCreator.verifyCertificate(cert.certificatePath(), Objects.requireNonNull(fullchain))
+                    certificateCreator.verifyCertificate(Objects.requireNonNull(fullchain), cert.certificatePath())
                 )
-                    .isEqualTo(true);
+                    .withFailMessage(ERR_VERIFY_FAILED)
+                    .isTrue();
+                assertThat(certificateCreator.isKeyEncrypted(childCert.certificateKeyPath()))
+                    .withFailMessage(ERR_NOT_ENCRYPTED)
+                    .isTrue();
             }
         }
     }