1 /* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 * HAWK is an HTTP authentication scheme using a message authentication code
7 * (MAC) algorithm to provide partial HTTP request cryptographic verification.
9 * For details, see: https://github.com/hueniverse/hawk
11 * With HAWK, it is essential that the clocks on clients and server not have an
12 * absolute delta of greater than one minute, as the HAWK protocol uses
13 * timestamps to reduce the possibility of replay attacks. However, it is
14 * likely that some clients' clocks will be more than a little off, especially
15 * in mobile devices, which would break HAWK-based services (like sync and
16 * firefox accounts) for those clients.
18 * This library provides a stateful HAWK client that calculates (roughly) the
19 * clock delta on the client vs the server. The library provides an interface
20 * for deriving HAWK credentials and making HAWK-authenticated REST requests to
21 * a single remote server. Therefore, callers who want to interact with
22 * multiple HAWK services should instantiate one HawkClient per service.
25 import { HAWKAuthenticatedRESTRequest } from "resource://services-common/hawkrequest.sys.mjs";
27 import { Observers } from "resource://services-common/observers.sys.mjs";
28 import { Log } from "resource://gre/modules/Log.sys.mjs";
29 import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
31 // log.appender.dump should be one of "Fatal", "Error", "Warn", "Info", "Config",
32 // "Debug", "Trace" or "All". If none is specified, "Error" will be used by
34 // Note however that Sync will also add this log to *its* DumpAppender, so
35 // in a Sync context it shouldn't be necessary to adjust this - however, that
36 // also means error logs are likely to be dump'd twice but that's OK.
37 const PREF_LOG_LEVEL = "services.common.hawk.log.appender.dump";
39 // A pref that can be set so "sensitive" information (eg, personally
40 // identifiable info, credentials, etc) will be logged.
41 const PREF_LOG_SENSITIVE_DETAILS = "services.common.hawk.log.sensitive";
45 XPCOMUtils.defineLazyGetter(lazy, "log", function () {
46 let log = Log.repository.getLogger("Hawk");
47 // We set the log itself to "debug" and set the level from the preference to
48 // the appender. This allows other things to send the logs to different
49 // appenders, while still allowing the pref to control what is seen via dump()
50 log.level = Log.Level.Debug;
51 let appender = new Log.DumpAppender();
52 log.addAppender(appender);
53 appender.level = Log.Level.Error;
56 Services.prefs.getPrefType(PREF_LOG_LEVEL) ==
57 Ci.nsIPrefBranch.PREF_STRING &&
58 Services.prefs.getCharPref(PREF_LOG_LEVEL);
59 appender.level = Log.Level[level] || Log.Level.Error;
67 // A boolean to indicate if personally identifiable information (or anything
68 // else sensitive, such as credentials) should be logged.
69 XPCOMUtils.defineLazyGetter(lazy, "logPII", function () {
71 return Services.prefs.getBoolPref(PREF_LOG_SENSITIVE_DETAILS);
78 * A general purpose client for making HAWK authenticated requests to a single
79 * host. Keeps track of the clock offset between the client and the host for
80 * computation of the timestamp in the HAWK Authorization header.
82 * Clients should create one HawkClient object per each server they wish to
88 export var HawkClient = function (host) {
91 // Clock offset in milliseconds between our client's clock and the date
92 // reported in responses from our host.
93 this._localtimeOffsetMsec = 0;
96 HawkClient.prototype = {
98 * Construct an error message for a response. Private.
100 * @param restResponse
101 * A RESTResponse object from a RESTRequest
104 * A string or object describing the error
106 _constructError(restResponse, error) {
109 // This object is likely to be JSON.stringify'd, but neither Error()
110 // objects nor Components.Exception objects do the right thing there,
111 // so we add a new element which is simply the .toString() version of
112 // the error object, so it does appear in JSON'd values.
113 errorString: error.toString(),
114 message: restResponse.statusText,
115 code: restResponse.status,
116 errno: restResponse.status,
118 return this.code + ": " + this.message;
122 restResponse.headers && restResponse.headers["retry-after"];
123 retryAfter = retryAfter ? parseInt(retryAfter) : retryAfter;
125 errorObj.retryAfter = retryAfter;
126 // and notify observers of the retry interval
127 if (this.observerPrefix) {
128 Observers.notify(this.observerPrefix + ":backoff:interval", retryAfter);
136 * Update clock offset by determining difference from date gives in the (RFC
137 * 1123) Date header of a server response. Because HAWK tolerates a window
138 * of one minute of clock skew (so two minutes total since the skew can be
139 * positive or negative), the simple method of calculating offset here is
140 * probably good enough. We keep the value in milliseconds to make life
141 * easier, even though the value will not have millisecond accuracy.
144 * An RFC 1123 date string (e.g., "Mon, 13 Jan 2014 21:45:06 GMT")
146 * For HAWK clock skew and replay protection, see
147 * https://github.com/hueniverse/hawk#replay-protection
149 _updateClockOffset(dateString) {
151 let serverDateMsec = Date.parse(dateString);
152 this._localtimeOffsetMsec = serverDateMsec - this.now();
154 "Clock offset vs " + this.host + ": " + this._localtimeOffsetMsec
157 lazy.log.warn("Bad date header in server response: " + dateString);
162 * Get the current clock offset in milliseconds.
164 * The offset is the number of milliseconds that must be added to the client
165 * clock to make it equal to the server clock. For example, if the client is
166 * five minutes ahead of the server, the localtimeOffsetMsec will be -300000.
168 get localtimeOffsetMsec() {
169 return this._localtimeOffsetMsec;
173 * return current time in milliseconds
179 /* A general method for sending raw RESTRequest calls authorized using HAWK
184 * The HTTP request method
188 * An object that can be encodable as JSON as the payload of the
190 * @param extraHeaders
191 * An object with header/value pairs to send with the request.
193 * Returns a promise that resolves to the response of the API call,
194 * or is rejected with an error. If the server response can be parsed
195 * as JSON and contains an 'error' property, the promise will be
196 * rejected with this JSON-parsed response.
206 method = method.toLowerCase();
208 let uri = this.host + path;
212 localtimeOffsetMsec: this.localtimeOffsetMsec,
213 headers: extraHeaders,
216 let request = this.newHAWKAuthenticatedRESTRequest(uri, credentials, extra);
218 let restResponse = await request[method](payloadObj).catch(e => {
219 // Keep a reference to the error, log a message about it, and return the
222 lazy.log.warn("hawk request error", error);
223 return request.response;
226 // This shouldn't happen anymore, but it's not exactly difficult to handle.
231 let status = restResponse.status;
239 restResponse.statusText
242 lazy.log.debug("Response text", restResponse.body);
245 // All responses may have backoff headers, which are a server-side safety
246 // valve to allow slowing down clients without hurting performance.
247 this._maybeNotifyBackoff(restResponse, "x-weave-backoff");
248 this._maybeNotifyBackoff(restResponse, "x-backoff");
251 // When things really blow up, reconstruct an error object that follows
252 // the general format of the server on error responses.
253 throw this._constructError(restResponse, error);
256 this._updateClockOffset(restResponse.headers.date);
258 if (status === 401 && retryOK && !("retry-after" in restResponse.headers)) {
259 // Retry once if we were rejected due to a bad timestamp.
260 // Clock offset is adjusted already in the top of this function.
261 lazy.log.debug("Received 401 for " + path + ": retrying");
272 // If the server returned a json error message, use it in the rejection
275 // In the case of a 401, in which we are probably being rejected for a
276 // bad timestamp, retry exactly once, during which time clock offset will
279 let jsonResponse = {};
281 jsonResponse = JSON.parse(restResponse.body);
284 let okResponse = 200 <= status && status < 300;
285 if (!okResponse || jsonResponse.error) {
286 if (jsonResponse.error) {
289 throw this._constructError(restResponse, "Request failed");
292 // It's up to the caller to know how to decode the response.
293 // We just return the whole response.
298 * The prefix used for all notifications sent by this module. This
299 * allows the handler of notifications to be sure they are handling
300 * notifications for the service they expect.
302 * If not set, no notifications will be sent.
304 observerPrefix: null,
306 // Given an optional header value, notify that a backoff has been requested.
307 _maybeNotifyBackoff(response, headerName) {
308 if (!this.observerPrefix || !response.headers) {
311 let headerVal = response.headers[headerName];
317 backoffInterval = parseInt(headerVal, 10);
320 "hawkclient response had invalid backoff value in '" +
328 this.observerPrefix + ":backoff:interval",
333 // override points for testing.
334 newHAWKAuthenticatedRESTRequest(uri, credentials, extra) {
335 return new HAWKAuthenticatedRESTRequest(uri, credentials, extra);