feat: Adds Pluggable Auth support (WIF)

oauth2_http/java/com/google/auth/oauth2/ExecutableHandler.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ *    * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.google.auth.oauth2;
+
+import java.io.IOException;
+import java.util.Map;
+import javax.annotation.Nullable;
+
+/** An interface for 3rd party executable handling. */
+interface ExecutableHandler {
+
+  /** An interface for required fields needed to call 3rd party executables. */
+  interface ExecutableOptions {
+
+    /** An absolute path to the command used to retrieve 3rd party tokens. */
+    String getExecutableCommand();
+
+    /** A set of process-local environment variable mappings to be set for the script to execute. */
+    Map<String, String> getEnvironmentMap();
+
+    /** A timeout for waiting for the executable to finish, in milliseconds. */
+    int getExecutableTimeoutMs();
+
+    /**
+     * An output file path which points to the 3rd party credentials generated by the executable.
+     */
+    @Nullable
+    String getOutputFilePath();
+  }
+
+  /**
+   * Handles executing the 3rd party script and parsing the token from the response.
+   *
+   * @param options A set executable options for handling the executable.
+   * @return A 3rd party token.
+   */
+  String retrieveTokenFromExecutable(ExecutableOptions options) throws IOException;
+}

oauth2_http/java/com/google/auth/oauth2/ExecutableResponse.java

@@ -0,0 +1,206 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ *    * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.google.auth.oauth2;
+
+import com.google.api.client.json.GenericJson;
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.time.Instant;
+import javax.annotation.Nullable;
+
+/**
+ * Encapsulates response values for the 3rd party executable response (e.g. OIDC, SAML, error
+ * responses).
+ */
+class ExecutableResponse {
+
+  private static final String SAML_SUBJECT_TOKEN_TYPE = "urn:ietf:params:oauth:token-type:saml2";
+
+  private final int version;
+  private final boolean success;
+
+  @Nullable private Long expirationTime;
+  @Nullable private String tokenType;
+  @Nullable private String subjectToken;
+  @Nullable private String errorCode;
+  @Nullable private String errorMessage;
+
+  ExecutableResponse(GenericJson json) throws IOException {
+    if (!json.containsKey("version")) {
+      throw new PluggableAuthException(
+          "INVALID_EXECUTABLE_RESPONSE", "The executable response is missing the `version` field.");
+    }
+
+    if (!json.containsKey("success")) {
+      throw new PluggableAuthException(
+          "INVALID_EXECUTABLE_RESPONSE", "The executable response is missing the `success` field.");
+    }
+
+    this.version = parseIntField(json.get("version"));
+    this.success = (boolean) json.get("success");
+
+    if (success) {
+      if (!json.containsKey("token_type")) {
+        throw new PluggableAuthException(
+            "INVALID_EXECUTABLE_RESPONSE",
+            "The executable response is missing the `token_type` field.");
+      }
+
+      if (!json.containsKey("expiration_time")) {
+        throw new PluggableAuthException(
+            "INVALID_EXECUTABLE_RESPONSE",
+            "The executable response is missing the `expiration_time` field.");
+      }
+
+      this.tokenType = (String) json.get("token_type");
+      this.expirationTime = parseLongField(json.get("expiration_time"));
+
+      if (SAML_SUBJECT_TOKEN_TYPE.equals(tokenType)) {
+        this.subjectToken = (String) json.get("saml_response");
+      } else {
+        this.subjectToken = (String) json.get("id_token");
+      }
+      if (subjectToken == null || subjectToken.isEmpty()) {
+        throw new PluggableAuthException(
+            "INVALID_EXECUTABLE_RESPONSE",
+            "The executable response does not contain a valid token.");
+      }
+    } else {
+      // Error response must contain both an error code and message.
+      this.errorCode = (String) json.get("code");
+      this.errorMessage = (String) json.get("message");
+      if (errorCode == null
+          || errorCode.isEmpty()
+          || errorMessage == null
+          || errorMessage.isEmpty()) {
+        throw new PluggableAuthException(
+            "INVALID_EXECUTABLE_RESPONSE",
+            "The executable response must contain `error` and `message` fields when unsuccessful.");
+      }
+    }
+  }
+
+  /**
+   * Returns the version of the executable output. Only version `1` is currently supported. This is
+   * useful for future changes to the expected output format.
+   *
+   * @return The version of the JSON output.
+   */
+  int getVersion() {
+    return this.version;
+  }
+
+  /**
+   * Returns the status of the response.
+   *
+   * <p>When this is true, the response will contain the 3rd party token for a sign in / refresh
+   * operation. When this is false, the response should contain an additional error code and
+   * message.
+   *
+   * @return Whether the `success` field in the executable response is true.
+   */
+  boolean isSuccessful() {
+    return this.success;
+  }
+
+  /** Returns true if the subject token is expired or not present, false otherwise. */
+  boolean isExpired() {
+    return this.expirationTime == null || this.expirationTime <= Instant.now().getEpochSecond();
+  }
+
+  /** Returns whether the execution was successful and returned an unexpired token. */
+  boolean isValid() {
+    return isSuccessful() && !isExpired();
+  }
+
+  /** Returns the subject token expiration time in seconds (Unix epoch time). */
+  @Nullable
+  Long getExpirationTime() {
+    return this.expirationTime;
+  }
+
+  /**
+   * Returns the 3rd party subject token type.
+   *
+   * <p>Possible valid values:
+   *
+   * <ul>
+   *   <li>urn:ietf:params:oauth:token-type:id_token
+   *   <li>urn:ietf:params:oauth:token-type:jwt
+   *   <li>urn:ietf:params:oauth:token-type:saml2
+   * </ul>
+   *
+   * @return The 3rd party subject token type for success responses, null otherwise.
+   */
+  @Nullable
+  String getTokenType() {
+    return this.tokenType;
+  }
+
+  /** Returns the subject token if the execution was successful, null otherwise. */
+  @Nullable
+  String getSubjectToken() {
+    return this.subjectToken;
+  }
+
+  /** Returns the error code if the execution was unsuccessful, null otherwise. */
+  @Nullable
+  String getErrorCode() {
+    return this.errorCode;
+  }
+
+  /** Returns the error message if the execution was unsuccessful, null otherwise. */
+  @Nullable
+  String getErrorMessage() {
+    return this.errorMessage;
+  }
+
+  private static int parseIntField(Object field) {
+    if (field instanceof String) {
+      return Integer.parseInt((String) field);
+    }
+    if (field instanceof BigDecimal) {
+      return ((BigDecimal) field).intValue();
+    }
+    return (int) field;
+  }
+
+  private static long parseLongField(Object field) {
+    if (field instanceof String) {
+      return Long.parseLong((String) field);
+    }
+    if (field instanceof BigDecimal) {
+      return ((BigDecimal) field).longValue();
+    }
+    return (long) field;
+  }
+}