gecko/services/crypto/modules/utils.js

378 lines
12 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
const EXPORTED_SYMBOLS = ["CryptoUtils"];
Cu.import("resource://services-common/observers.js");
Cu.import("resource://services-common/utils.js");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
let CryptoUtils = {
/**
* Generate a string of random bytes.
*/
generateRandomBytes: function generateRandomBytes(length) {
let rng = Cc["@mozilla.org/security/random-generator;1"]
.createInstance(Ci.nsIRandomGenerator);
let bytes = rng.generateRandomBytes(length);
return CommonUtils.byteArrayToString(bytes);
},
/**
* UTF8-encode a message and hash it with the given hasher. Returns a
* string containing bytes. The hasher is reset if it's an HMAC hasher.
*/
digestUTF8: function digestUTF8(message, hasher) {
let data = this._utf8Converter.convertToByteArray(message, {});
hasher.update(data, data.length);
let result = hasher.finish(false);
if (hasher instanceof Ci.nsICryptoHMAC) {
hasher.reset();
}
return result;
},
/**
* Treat the given message as a bytes string and hash it with the given
* hasher. Returns a string containing bytes. The hasher is reset if it's
* an HMAC hasher.
*/
digestBytes: function digestBytes(message, hasher) {
// No UTF-8 encoding for you, sunshine.
let bytes = [b.charCodeAt() for each (b in message)];
hasher.update(bytes, bytes.length);
let result = hasher.finish(false);
if (hasher instanceof Ci.nsICryptoHMAC) {
hasher.reset();
}
return result;
},
/**
* UTF-8 encode a message and perform a SHA-1 over it.
*
* @param message
* (string) Buffer to perform operation on. Should be a JS string.
* It is possible to pass in a string representing an array
* of bytes. But, you probably don't want to UTF-8 encode
* such data and thus should not be using this function.
*
* @return string
* Raw bytes constituting SHA-1 hash. Value is a JS string. Each
* character is the byte value for that offset. Returned string
* always has .length == 20.
*/
UTF8AndSHA1: function UTF8AndSHA1(message) {
let hasher = Cc["@mozilla.org/security/hash;1"]
.createInstance(Ci.nsICryptoHash);
hasher.init(hasher.SHA1);
return CryptoUtils.digestUTF8(message, hasher);
},
sha1: function sha1(message) {
return CommonUtils.bytesAsHex(CryptoUtils.UTF8AndSHA1(message));
},
sha1Base32: function sha1Base32(message) {
return CommonUtils.encodeBase32(CryptoUtils.UTF8AndSHA1(message));
},
/**
* Produce an HMAC key object from a key string.
*/
makeHMACKey: function makeHMACKey(str) {
return Svc.KeyFactory.keyFromString(Ci.nsIKeyObject.HMAC, str);
},
/**
* Produce an HMAC hasher and initialize it with the given HMAC key.
*/
makeHMACHasher: function makeHMACHasher(type, key) {
let hasher = Cc["@mozilla.org/security/hmac;1"]
.createInstance(Ci.nsICryptoHMAC);
hasher.init(type, key);
return hasher;
},
/**
* HMAC-based Key Derivation Step 2 according to RFC 5869.
*/
hkdfExpand: function hkdfExpand(prk, info, len) {
const BLOCKSIZE = 256 / 8;
let h = CryptoUtils.makeHMACHasher(Ci.nsICryptoHMAC.SHA256,
CryptoUtils.makeHMACKey(prk));
let T = "";
let Tn = "";
let iterations = Math.ceil(len/BLOCKSIZE);
for (let i = 0; i < iterations; i++) {
Tn = CryptoUtils.digestBytes(Tn + info + String.fromCharCode(i + 1), h);
T += Tn;
}
return T.slice(0, len);
},
/**
* PBKDF2 implementation in Javascript.
*
* The arguments to this function correspond to items in
* PKCS #5, v2.0 pp. 9-10
*
* P: the passphrase, an octet string: e.g., "secret phrase"
* S: the salt, an octet string: e.g., "DNXPzPpiwn"
* c: the number of iterations, a positive integer: e.g., 4096
* dkLen: the length in octets of the destination
* key, a positive integer: e.g., 16
*
* The output is an octet string of length dkLen, which you
* can encode as you wish.
*/
pbkdf2Generate : function pbkdf2Generate(P, S, c, dkLen) {
// We don't have a default in the algo itself, as NSS does.
// Use the constant.
if (!dkLen) {
dkLen = SYNC_KEY_DECODED_LENGTH;
}
/* For HMAC-SHA-1 */
const HLEN = 20;
function F(S, c, i, h) {
function XOR(a, b, isA) {
if (a.length != b.length) {
return false;
}
let val = [];
for (let i = 0; i < a.length; i++) {
if (isA) {
val[i] = a[i] ^ b[i];
} else {
val[i] = a.charCodeAt(i) ^ b.charCodeAt(i);
}
}
return val;
}
let ret;
let U = [];
/* Encode i into 4 octets: _INT */
let I = [];
I[0] = String.fromCharCode((i >> 24) & 0xff);
I[1] = String.fromCharCode((i >> 16) & 0xff);
I[2] = String.fromCharCode((i >> 8) & 0xff);
I[3] = String.fromCharCode(i & 0xff);
U[0] = CryptoUtils.digestBytes(S + I.join(''), h);
for (let j = 1; j < c; j++) {
U[j] = CryptoUtils.digestBytes(U[j - 1], h);
}
ret = U[0];
for (j = 1; j < c; j++) {
ret = CommonUtils.byteArrayToString(XOR(ret, U[j]));
}
return ret;
}
let l = Math.ceil(dkLen / HLEN);
let r = dkLen - ((l - 1) * HLEN);
// Reuse the key and the hasher. Remaking them 4096 times is 'spensive.
let h = CryptoUtils.makeHMACHasher(Ci.nsICryptoHMAC.SHA1,
CryptoUtils.makeHMACKey(P));
T = [];
for (let i = 0; i < l;) {
T[i] = F(S, c, ++i, h);
}
let ret = "";
for (i = 0; i < l-1;) {
ret += T[i++];
}
ret += T[l - 1].substr(0, r);
return ret;
},
deriveKeyFromPassphrase: function deriveKeyFromPassphrase(passphrase,
salt,
keyLength,
forceJS) {
if (Svc.Crypto.deriveKeyFromPassphrase && !forceJS) {
return Svc.Crypto.deriveKeyFromPassphrase(passphrase, salt, keyLength);
}
else {
// Fall back to JS implementation.
// 4096 is hardcoded in WeaveCrypto, so do so here.
return CryptoUtils.pbkdf2Generate(passphrase, atob(salt), 4096,
keyLength);
}
},
/**
* Compute the HTTP MAC SHA-1 for an HTTP request.
*
* @param identifier
* (string) MAC Key Identifier.
* @param key
* (string) MAC Key.
* @param method
* (string) HTTP request method.
* @param URI
* (nsIURI) HTTP request URI.
* @param extra
* (object) Optional extra parameters. Valid keys are:
* nonce_bytes - How many bytes the nonce should be. This defaults
* to 8. Note that this many bytes are Base64 encoded, so the
* string length of the nonce will be longer than this value.
* ts - Timestamp to use. Should only be defined for testing.
* nonce - String nonce. Should only be defined for testing as this
* function will generate a cryptographically secure random one
* if not defined.
* ext - Extra string to be included in MAC. Per the HTTP MAC spec,
* the format is undefined and thus application specific.
* @returns
* (object) Contains results of operation and input arguments (for
* symmetry). The object has the following keys:
*
* identifier - (string) MAC Key Identifier (from arguments).
* key - (string) MAC Key (from arguments).
* method - (string) HTTP request method (from arguments).
* hostname - (string) HTTP hostname used (derived from arguments).
* port - (string) HTTP port number used (derived from arguments).
* mac - (string) Raw HMAC digest bytes.
* getHeader - (function) Call to obtain the string Authorization
* header value for this invocation.
* nonce - (string) Nonce value used.
* ts - (number) Integer seconds since Unix epoch that was used.
*/
computeHTTPMACSHA1: function computeHTTPMACSHA1(identifier, key, method,
uri, extra) {
let ts = (extra && extra.ts) ? extra.ts : Math.floor(Date.now() / 1000);
let nonce_bytes = (extra && extra.nonce_bytes > 0) ? extra.nonce_bytes : 8;
// We are allowed to use more than the Base64 alphabet if we want.
let nonce = (extra && extra.nonce)
? extra.nonce
: btoa(CryptoUtils.generateRandomBytes(nonce_bytes));
let host = uri.asciiHost;
let port;
let usedMethod = method.toUpperCase();
if (uri.port != -1) {
port = uri.port;
} else if (uri.scheme == "http") {
port = "80";
} else if (uri.scheme == "https") {
port = "443";
} else {
throw new Error("Unsupported URI scheme: " + uri.scheme);
}
let ext = (extra && extra.ext) ? extra.ext : "";
let requestString = ts.toString(10) + "\n" +
nonce + "\n" +
usedMethod + "\n" +
uri.path + "\n" +
host + "\n" +
port + "\n" +
ext + "\n";
let hasher = CryptoUtils.makeHMACHasher(Ci.nsICryptoHMAC.SHA1,
CryptoUtils.makeHMACKey(key));
let mac = CryptoUtils.digestBytes(requestString, hasher);
function getHeader() {
return CryptoUtils.getHTTPMACSHA1Header(this.identifier, this.ts,
this.nonce, this.mac, this.ext);
}
return {
identifier: identifier,
key: key,
method: usedMethod,
hostname: host,
port: port,
mac: mac,
nonce: nonce,
ts: ts,
ext: ext,
getHeader: getHeader
};
},
/**
* Obtain the HTTP MAC Authorization header value from fields.
*
* @param identifier
* (string) MAC key identifier.
* @param ts
* (number) Integer seconds since Unix epoch.
* @param nonce
* (string) Nonce value.
* @param mac
* (string) Computed HMAC digest (raw bytes).
* @param ext
* (optional) (string) Extra string content.
* @returns
* (string) Value to put in Authorization header.
*/
getHTTPMACSHA1Header: function getHTTPMACSHA1Header(identifier, ts, nonce,
mac, ext) {
let header ='MAC id="' + identifier + '", ' +
'ts="' + ts + '", ' +
'nonce="' + nonce + '", ' +
'mac="' + btoa(mac) + '"';
if (!ext) {
return header;
}
return header += ', ext="' + ext +'"';
},
};
XPCOMUtils.defineLazyGetter(CryptoUtils, "_utf8Converter", function() {
let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
.createInstance(Ci.nsIScriptableUnicodeConverter);
converter.charset = "UTF-8";
return converter;
});
let Svc = {};
XPCOMUtils.defineLazyServiceGetter(Svc,
"KeyFactory",
"@mozilla.org/security/keyobjectfactory;1",
"nsIKeyObjectFactory");
Svc.__defineGetter__("Crypto", function() {
let ns = {};
Cu.import("resource://services-crypto/WeaveCrypto.js", ns);
let wc = new ns.WeaveCrypto();
delete Svc.Crypto;
return Svc.Crypto = wc;
});
Observers.add("xpcom-shutdown", function unloadServices() {
Observers.remove("xpcom-shutdown", unloadServices);
for (let k in Svc) {
delete Svc[k];
}
});