Enhance for JsonParser, API for loading trust bundle from file and ex…

…traction of SPIFFE uri from leaf certs

core/src/main/java/io/grpc/internal/JsonParser.java

@@ -46,7 +46,7 @@ private JsonParser() {}
   public static Object parse(String raw) throws IOException {
     JsonReader jr = new JsonReader(new StringReader(raw));
     try {
-      return parseRecursive(jr);
+      return parseRecursive(jr, false);
     } finally {
       try {
         jr.close();
@@ -56,13 +56,32 @@ public static Object parse(String raw) throws IOException {
     }
   }
 
-  private static Object parseRecursive(JsonReader jr) throws IOException {
+  /**
+   * Parses a json string, returning either a {@code Map<String, ?>}, {@code List<?>},
+   * {@code String}, {@code Double}, {@code Boolean}, or {@code null}. Fails if duplicate names
+   * found.
+   */
+  public static Object parseNoDuplicates(String raw) throws IOException {
+    JsonReader jr = new JsonReader(new StringReader(raw));
+    try {
+      return parseRecursive(jr, true);
+    } finally {
+      try {
+        jr.close();
+      } catch (IOException e) {
+        logger.log(Level.WARNING, "Failed to close", e);
+      }
+    }
+  }
+
+  private static Object parseRecursive(JsonReader jr, Boolean... failOnDuplicates)
+      throws IOException {
     checkState(jr.hasNext(), "unexpected end of JSON");
     switch (jr.peek()) {
       case BEGIN_ARRAY:
-        return parseJsonArray(jr);
+        return parseJsonArray(jr, failOnDuplicates);
       case BEGIN_OBJECT:
-        return parseJsonObject(jr);
+        return parseJsonObject(jr, failOnDuplicates);
       case STRING:
         return jr.nextString();
       case NUMBER:
@@ -76,24 +95,28 @@ private static Object parseRecursive(JsonReader jr) throws IOException {
     }
   }
 
-  private static Map<String, ?> parseJsonObject(JsonReader jr) throws IOException {
+  private static Map<String, ?> parseJsonObject(JsonReader jr, Boolean... failOnDuplicates)
+      throws IOException {
     jr.beginObject();
     Map<String, Object> obj = new LinkedHashMap<>();
     while (jr.hasNext()) {
       String name = jr.nextName();
-      Object value = parseRecursive(jr);
+      if (failOnDuplicates.length > 0 && failOnDuplicates[0] && obj.containsKey(name)) {
+        throw new IllegalArgumentException("Duplicate key found: " + name);
+      }
+      Object value = parseRecursive(jr, failOnDuplicates);
       obj.put(name, value);
     }
     checkState(jr.peek() == JsonToken.END_OBJECT, "Bad token: " + jr.getPath());
     jr.endObject();
     return Collections.unmodifiableMap(obj);
   }
 
-  private static List<?> parseJsonArray(JsonReader jr) throws IOException {
+  private static List<?> parseJsonArray(JsonReader jr, Boolean... params) throws IOException {
     jr.beginArray();
     List<Object> array = new ArrayList<>();
     while (jr.hasNext()) {
-      Object value = parseRecursive(jr);
+      Object value = parseRecursive(jr, params);
       array.add(value);
     }
     checkState(jr.peek() == JsonToken.END_ARRAY, "Bad token: " + jr.getPath());
@@ -105,4 +128,4 @@ private static Void parseJsonNull(JsonReader jr) throws IOException {
     jr.nextNull();
     return null;
   }
-}
+}

core/src/main/java/io/grpc/internal/SpiffeUtil.java

@@ -19,15 +19,43 @@
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 
+import com.google.common.base.Optional;
 import com.google.common.base.Splitter;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.security.cert.Certificate;
+import java.security.cert.CertificateException;
+import java.security.cert.CertificateFactory;
+import java.security.cert.CertificateParsingException;
+import java.security.cert.X509Certificate;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Locale;
+import java.util.Map;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 /**
- * Helper utility to work with SPIFFE URIs.
+ * Provides utilities to load, extract, and parse SPIFFE ID according the SPIFFE ID standard.
  * @see <a href="https://github.com/spiffe/spiffe/blob/master/standards/SPIFFE-ID.md">Standard</a>
  */
 public final class SpiffeUtil {
 
+  private static final Logger log = Logger.getLogger(SpiffeUtil.class.getName());
+
+  private static final Integer URI_SAN_TYPE = 6;
+  private static final String USE_PARAMETER_VALUE = "x509-svid";
+  private static final String KTY_PARAMETER_VALUE = "RSA";
   private static final String PREFIX = "spiffe://";
 
   private SpiffeUtil() {}
@@ -96,6 +124,139 @@ private static void validatePathSegment(String pathSegment) {
             + " ([a-zA-Z0-9.-_])");
   }
 
+  /**
+   * Returns the SPIFFE ID from the leaf certificate, if present.
+   *
+   * @param certChain certificate chain to extract SPIFFE ID from
+   */
+  public static Optional<SpiffeId> extractSpiffeId(X509Certificate[] certChain)
+      throws CertificateParsingException {
+    checkArgument(checkNotNull(certChain, "certChain").length > 0, "CertChain can't be empty");
+    Collection<List<?>> subjectAltNames = certChain[0].getSubjectAlternativeNames();
+    if (subjectAltNames == null) {
+      return Optional.absent();
+    }
+    String uri = null;
+    for (List<?> altName : subjectAltNames) {
+      if (altName.size() < 2 ) {
+        continue;
+      }
+      if (URI_SAN_TYPE.equals(altName.get(0))) {
+        if (uri != null) {
+          throw new IllegalArgumentException("Multiple URI SAN values found in the leaf cert.");
+        }
+        uri = (String) altName.get(1);
+      }
+    }
+    if (uri == null) {
+      return Optional.absent();
+    }
+    return Optional.of(parse(uri));
+  }
+
+  /**
+   * Loads a SPIFFE trust bundle from a file, parsing it from the JSON format.
+   * In case of success, returns trust domains, their associated sequence numbers, and X.509
+   * certificates.
+   *
+   * @param trustBundleFile the file path to the JSON file containing the trust bundle
+   * @see <a href="https://github.com/spiffe/spiffe/blob/main/standards/SPIFFE_Trust_Domain_and_Bundle.md">JSON format</a>
+   * @see <a href="https://github.com/spiffe/spiffe/blob/main/standards/X509-SVID.md#61-publishing-spiffe-bundle-elements">JWK entry format</a>
+   */
+  public static SpiffeBundle loadTrustBundleFromFile(String trustBundleFile) throws IOException {
+    Map<String, ?> trustDomainsNode = readTrustDomainsFromFile(trustBundleFile);
+    Map<String, List<X509Certificate>> trustBundleMap = new HashMap<>();
+    Map<String, Long> sequenceNumbers = new HashMap<>();
+    for (String trustDomainName : trustDomainsNode.keySet()) {
+      Map<String, ?> domainNode = JsonUtil.getObject(trustDomainsNode, trustDomainName);
+      if (domainNode == null || domainNode.size() == 0) {
+        trustBundleMap.put(trustDomainName, Collections.emptyList());
+        continue;
+      }
+      Long sequenceNumber = JsonUtil.getNumberAsLong(domainNode, "sequence_number");
+      sequenceNumbers.put(trustDomainName, sequenceNumber == null ? -1L : sequenceNumber);
+      List<Map<String, ?>> keysNode = JsonUtil.getListOfObjects(domainNode, "keys");
+      if (keysNode == null || keysNode.size() == 0) {
+        trustBundleMap.put(trustDomainName, Collections.emptyList());
+        continue;
+      }
+      trustBundleMap.put(trustDomainName, extractCert(keysNode, trustDomainName));
+    }
+    return new SpiffeBundle(sequenceNumbers, trustBundleMap);
+  }
+
+  private static Map<String, ?> readTrustDomainsFromFile(String filePath) throws IOException {
+    Path path = Paths.get(checkNotNull(filePath, "trustBundleFile"));
+    String json = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
+    Object jsonObject = JsonParser.parseNoDuplicates(json);
+    if (!(jsonObject instanceof Map)) {
+      throw new IllegalArgumentException(
+          "SPIFFE Trust Bundle should be a JSON object. Found: "
+              + (jsonObject == null ? null : jsonObject.getClass()));
+    }
+    @SuppressWarnings("unchecked")
+    Map<String, ?> root = (Map<String, ?>)jsonObject;
+    Map<String, ?> trustDomainsNode = JsonUtil.getObject(root, "trust_domains");
+    checkArgument(checkNotNull(trustDomainsNode,
+            "Mandatory trust_domains element is missing").size() > 0,
+        "Mandatory trust_domains element is missing");
+    return trustDomainsNode;
+  }
+
+  private static boolean checkJwkEntry(Map<String, ?> jwkNode, String trustDomainName) {
+    String kty = JsonUtil.getString(jwkNode, "kty");
+    if (kty == null || !kty.equals(KTY_PARAMETER_VALUE)) {
+      log.log(Level.SEVERE, String.format("'kty' parameter must be '%s' but '%s' found. "
+              + "Skipping certificate loading for trust domain '%s'.", KTY_PARAMETER_VALUE, kty,
+          trustDomainName));
+      return false;
+    }
+    String kid = JsonUtil.getString(jwkNode, "kid");
+    if (kid != null && !kid.equals("")) {
+      log.log(Level.SEVERE, String.format("'kid' parameter must not be set but value '%s' "
+              + "found. Skipping certificate loading for trust domain '%s'.", kid,
+          trustDomainName));
+      return false;
+    }
+    String use = JsonUtil.getString(jwkNode, "use");
+    if (use == null || !use.equals(USE_PARAMETER_VALUE)) {
+      log.log(Level.SEVERE, String.format("'use' parameter must be '%s' but '%s' found. "
+              + "Skipping certificate loading for trust domain '%s'.", USE_PARAMETER_VALUE, use,
+          trustDomainName));
+      return false;
+    }
+    return true;
+  }
+
+  private static List<X509Certificate> extractCert(List<Map<String, ?>> keysNode,
+      String trustDomainName) {
+    List<X509Certificate> result = new ArrayList<>();
+    for (Map<String, ?> keyNode : keysNode) {
+      if (!checkJwkEntry(keyNode, trustDomainName)) {
+        break;
+      }
+      String rawCert = JsonUtil.getString(keyNode, "x5c");
+      if (rawCert == null) {
+        break;
+      }
+      InputStream stream = new ByteArrayInputStream(rawCert.getBytes(StandardCharsets.UTF_8));
+      try {
+        Collection<? extends Certificate> certs = CertificateFactory.getInstance("X509")
+            .generateCertificates(stream);
+        if (certs.size() != 1) {
+          log.log(Level.SEVERE, String.format("Exactly 1 certificate is expected, but %s found for "
+              + "domain %s.", certs.size(), trustDomainName));
+        } else {
+          result.add(certs.toArray(new X509Certificate[0])[0]);
+        }
+      } catch (CertificateException e) {
+        log.log(Level.SEVERE, String.format("Certificate for domain %s can't be parsed.",
+            trustDomainName), e);
+      }
+    }
+    return result;
+  }
+
   /**
    * Represents a SPIFFE ID as defined in the SPIFFE standard.
    * @see <a href="https://github.com/spiffe/spiffe/blob/master/standards/SPIFFE-ID.md">Standard</a>
@@ -119,4 +280,34 @@ public String getPath() {
     }
   }
 
+  /**
+   * Represents a Trust Bundle inspired by SPIFFE Bundle Format standard. Only trust domain's
+   * sequence numbers and x509 certificates are supported.
+   * @see <a href="https://github.com/spiffe/spiffe/blob/main/standards/SPIFFE_Trust_Domain_and_Bundle.md#4-spiffe-bundle-format">Standard</a>
+   */
+  public static final class SpiffeBundle {
+
+    private final ImmutableMap<String, Long> sequenceNumbers;
+
+    private final ImmutableMap<String, ImmutableList<X509Certificate>> bundleMap;
+
+    public SpiffeBundle(Map<String, Long> sequenceNumbers,
+        Map<String, List<X509Certificate>> trustDomainMap) {
+      this.sequenceNumbers = ImmutableMap.copyOf(sequenceNumbers);
+      ImmutableMap.Builder<String, ImmutableList<X509Certificate>> builder = ImmutableMap.builder();
+      for (Map.Entry<String, List<X509Certificate>> entry : trustDomainMap.entrySet()) {
+        builder.put(entry.getKey(), ImmutableList.copyOf(entry.getValue()));
+      }
+      this.bundleMap = builder.build();
+    }
+
+    public ImmutableMap<String, Long> getSequenceNumbers() {
+      return sequenceNumbers;
+    }
+
+    public ImmutableMap<String, ImmutableList<X509Certificate>> getBundleMap() {
+      return bundleMap;
+    }
+  }
+
 }

core/src/test/java/io/grpc/internal/JsonParserTest.java

@@ -123,4 +123,11 @@ public void objectStringName() throws IOException {
 
     assertEquals(expected, JsonParser.parse("{\"hi\": 2}"));
   }
-}
+
+  @Test
+  public void duplicate() throws IOException {
+    thrown.expect(IllegalArgumentException.class);
+
+    JsonParser.parseNoDuplicates("{\"hi\": 2, \"hi\": 3}");
+  }
+}