Update algorithm to sign header names.

- See issue #10.
- Header names must be included in the signed string to avoid an issue
  where an attacker could switch header list order and header value
  order and end up with the same signature for different requests.
- Update parser, signer, and tests.
- Slight change to signer to always treat 'request-line' as the request
  line and never check for a header named 'Request-Line'.
- Add test from spec into a test file.
- Update spec text and example values.

http_signing.md

@@ -92,20 +92,26 @@ OPTIONAL.  The `extensions` parameter is used to include additional information
 which is covered by the request.  The content and format of the string is out of
 scope for this document, and expected to be specified by implementors.
 
-### Digital Signature
+#### sig
 
-The `digitalSignature` portion of the credentials is a REQUIRED field, and is
+REQUIRED.  The `sig` parameter is a `Base64` encoded digital signature
 generated by the client. The client uses the `algorithm` and `headers` request
 parameters to form a canonicalized `signing string`.  This `signing string` is
-then signed with the key associated with `keyId` and the algorithm corresponding
-to `algorithm`.  The result is then `Base64` encoded.
+then signed with the key associated with `keyId` and the algorithm
+corresponding to `algorithm`.  The `sig` parameter is then set to the `Base64`
+encoding of the signature.
 
 ### Signing String Composition
 
-In order to generate the string that is signed with a key, the client MUST
-take the values of each HTTP header specified by `headers`, in the order they
-appear, and separate with an ASCII newline `\n`.  The last header in the list
-MUST NOT include a trailing ASCII newline.
+In order to generate the string that is signed with a key, the client MUST take
+the values of each HTTP header specified by `headers` in the order they appear.
+
+1. If the header name is not `request-line` then append the lowercased header
+   name followed with an ASCII colon `:` and an ASCII space ` `.
+2. If the header name is `request-line` then appened the HTTP request line,
+   otherwise append the header value.
+3. If value is not the last value then append an ASCII newline `\n`. The string
+   MUST NOT include a trailing ASCII newline.
 
 # Example Requests
 
@@ -129,9 +135,19 @@ All requests refer to the following request (body ommitted):
 The client would compose the signing string as (`+ "\n"` inserted for
 readability):
 
-    application/json + "\n"
-    Tue, 07 Jun 2011 20:51:35 GMT + "\n"
-    h0auK8hnYJKmHTLhKtMTkQ==
+    content-type: application/json + "\n"
+    date: Tue, 07 Jun 2011 20:51:35 GMT + "\n"
+    content-md5: h0auK8hnYJKmHTLhKtMTkQ==
+
+## Header List with `request-line`
+
+    Authorization: Signature keyId="123",headers="date request-line" Base64(RSA-SHA256(Tue, 07 Jun 2011 20:51:35 GMT))
+
+The client would compose the signing string as (`+ "\n"` inserted for
+readability):
+
+    date: Tue, 07 Jun 2011 20:51:35 GMT + "\n"
+    POST /foo HTTP/1.1
 
 ## Algorithm
 
@@ -246,28 +262,27 @@ And all examples use this request:
 The string to sign would be:
 
 ```
-Thu, 05 Jan 2012 21:31:40 GMT
+date: Thu, 05 Jan 2012 21:31:40 GMT
 ```
 
 The Authorization header would be:
 
-    Authorization: Signature keyId="Test",algorithm="rsa-sha256" MDyO5tSvin5FBVdq3gMBTwtVgE8U/JpzSwFvY7gu7Q2tiZ5TvfHzf/RzmRoYwO8PoV1UGaw6IMwWzxDQkcoYOwvG/w4ljQBBoNusO/mYSvKrbqxUmZi8rNtrMcb82MS33bai5IeLnOGl31W1UbL4qE/wL8U9wCPGRJlCFLsTgD8=
+    Authorization: Signature keyId="Test",algorithm="rsa-sha256" JldXnt8W9t643M2Sce10gqCh/+E7QIYLiI+bSjnFBGCti7s+mPPvOjVb72sbd1FjeOUwPTDpKbrQQORrm+xBYfAwCxF3LBSSzORvyJ5nRFCFxfJ3nlQD6Kdxhw8wrVZX5nSem4A/W3C8qH5uhFTRwF4ruRjh+ENHWuovPgO/HGQ=
 
 ### All Headers
 
 Parameterized to include all headers, the string to sign would be:
 
 ```
-/foo?param=value&pet=dog HTTP/1.1
-example.com
-Thu, 05 Jan 2012 21:31:40 GMT
-application/json
-Sd/dVLAcvNLSq16eXua5uQ==
-18
+POST /foo?param=value&pet=dog HTTP/1.1
+host: example.com
+date: Thu, 05 Jan 2012 21:31:40 GMT
+content-type: application/json
+content-md5: Sd/dVLAcvNLSq16eXua5uQ==
+content-length: 18
 ```
 
 The Authorization header would be:
 
-    Authorization: Signature
-    keyId="Test",algorithm="rsa-sha256",headers="request-line host date content-type content-md5 content-length" gVrKP7wVh1+FmWbNlhj0pNXIe9XmeOA6EcnoOKAvUILnwaMFzaKaam9UmeDPwjC9TdT+jSRqjtyZE49kZcSpYAHxGlPQ4ziXFRfPprlN/3Xwg3sUOGqbBiS3WFuY3QOOWv4tzc5p70g74U/QvHNNiYMcjoz89vRJhefbFSNwCDs=
+    Authorization: Signature keyId="Test",algorithm="rsa-sha256",headers="request-line host date content-type content-md5 content-length" Gm7W/r+e90REDpWytALMrft4MqZxCmslOTOvwJX17ViEBA5E65QqvWI0vIH3l/vSsGiaMVmuUgzYsJLYMLcm5dGrv1+a+0fCoUdVKPZWHyImQEqpLkopVwqEH67LVECFBqFTAKlQgBn676zrfXQbb+b/VebAsNUtvQMe6cTjnDY=
 

lib/parser.js

@@ -237,17 +237,16 @@ module.exports = {
       var h = parsed.params.headers[i].toLowerCase();
       parsed.params.headers[i] = h;
 
-      var value;
       if (h !== 'request-line') {
-        value = request.headers[h];
+        var value = request.headers[h];
         if (!value)
           throw new MissingHeaderError(h + ' was not in the request');
+        parsed.signingString += h + ': ' + value;
       } else {
-        value =
+        parsed.signingString +=
           request.method + ' ' + request.url + ' HTTP/' + request.httpVersion;
       }
 
-      parsed.signingString += value;
       if ((i + 1) < parsed.params.headers.length)
         parsed.signingString += '\n';
     }

lib/signer.js

@@ -133,18 +133,18 @@ module.exports = {
         throw new TypeError('options.headers must be an array of Strings');
 
       var h = options.headers[i].toLowerCase();
-      request.getHeader(h);
 
-      var value = request.getHeader(h);
-      if (!value) {
-        if (h === 'request-line') {
-          value = request.method + ' ' + request.path + ' HTTP/1.1';
-        } else {
+      if (h !== 'request-line') {
+        var value = request.getHeader(h);
+        if (!value) {
           throw new MissingHeaderError(h + ' was not in the request');
         }
+        stringToSign += h + ': ' + value;
+      } else {
+        value =
+        stringToSign += request.method + ' ' + request.path + ' HTTP/1.1';
       }
 
-      stringToSign += value;
       if ((i + 1) < options.headers.length)
         stringToSign += '\n';
     }

test/parser.test.js

@@ -373,8 +373,8 @@ test('valid explicit headers', function(t) {
       t.equal(parsed.signature, 'digitalSignature');
       t.ok(parsed.signingString);
       t.equal(parsed.signingString,
-                   (options.headers.Date + '\n' +
-                    options.headers['content-md5'] + '\n' +
+                   ('date: ' + options.headers.Date + '\n' +
+                    'content-md5: ' + options.headers['content-md5'] + '\n' +
                     'GET / HTTP/1.1'));
       t.equal(parsed.params.keyId, parsed.keyId);
       t.equal(parsed.params.algorithm.toUpperCase(),

test/verify.test.js

@@ -120,7 +120,7 @@ test('valid hmac', function(t) {
 
   options.headers.Date = _rfc1123();
   var hmac = crypto.createHmac('sha1', hmacKey);
-  hmac.update(options.headers.Date);
+  hmac.update('date: ' + options.headers.Date);
   options.headers.Authorization =
     'Signature keyId="foo",algorithm="hmac-sha1" ' +
     hmac.digest('base64');
@@ -166,7 +166,7 @@ test('valid rsa', function(t) {
 
   options.headers.Date = _rfc1123();
   var signer = crypto.createSign('RSA-SHA256');
-  signer.update(options.headers.Date);
+  signer.update('date: ' + options.headers.Date);
   options.headers.Authorization =
     'Signature keyId="foo",algorithm="rsa-sha256" ' +
     signer.sign(rsaPrivate, 'base64');
@@ -178,6 +178,79 @@ test('valid rsa', function(t) {
 });
 
 
+// test values from spec for defaults
+test('valid rsa from spec default', function(t) {
+  server.tester = function(req, res) {
+    console.log('> [DEFAULT]', req.headers.authorization);
+    var parsed = httpSignature.parseRequest(req);
+    t.ok(httpSignature.verify(parsed, rsaPublic));
+
+    res.writeHead(200);
+    res.write(JSON.stringify(parsed, null, 2));
+    res.end();
+  };
+
+  options.method = 'POST';
+  options.path = '/foo?param=value&pet=dog';
+  options.headers.host = 'example.com';
+  options.headers.Date = _rfc1123();
+  options.headers['content-type'] = 'application/json';
+  options.headers['content-md5'] = 'Sd/dVLAcvNLSq16eXua5uQ==';
+  options.headers['content-length'] = '18';
+  var signer = crypto.createSign('RSA-SHA256');
+  signer.update('date: ' + options.headers.Date);
+  options.headers.Authorization =
+    'Signature keyId="Test",algorithm="rsa-sha256"' +
+    ' ' + signer.sign(rsaPrivate, 'base64');
+
+  var req = http.request(options, function(res) {
+    t.equal(res.statusCode, 200);
+    t.end();
+  });
+  req.write('{"hello": "world"}');
+  req.end();
+});
+
+// test values from spec for all headers
+test('valid rsa from spec all headers', function(t) {
+  server.tester = function(req, res) {
+    console.log('> [ALL]', req.headers.authorization);
+    var parsed = httpSignature.parseRequest(req);
+    t.ok(httpSignature.verify(parsed, rsaPublic));
+
+    res.writeHead(200);
+    res.write(JSON.stringify(parsed, null, 2));
+    res.end();
+  };
+
+  options.method = 'POST';
+  options.path = '/foo?param=value&pet=dog';
+  options.headers.host = 'example.com';
+  options.headers.Date = _rfc1123();
+  options.headers['content-type'] = 'application/json';
+  options.headers['content-md5'] = 'Sd/dVLAcvNLSq16eXua5uQ==';
+  options.headers['content-length'] = '18';
+  var signer = crypto.createSign('RSA-SHA256');
+  signer.update(options.method + ' ' + options.path + ' HTTP/1.1\n');
+  signer.update('host: ' + options.headers.host + '\n');
+  signer.update('date: ' + options.headers.Date + '\n');
+  signer.update('content-type: ' + options.headers['content-type'] + '\n');
+  signer.update('content-md5: ' + options.headers['content-md5'] + '\n');
+  signer.update('content-length: ' + options.headers['content-length']);
+  options.headers.Authorization =
+    'Signature keyId="Test",algorithm="rsa-sha256",headers=' +
+    '"request-line host date content-type content-md5 content-length"' +
+    ' ' + signer.sign(rsaPrivate, 'base64');
+
+  var req = http.request(options, function(res) {
+    t.equal(res.statusCode, 200);
+    t.end();
+  });
+  req.write('{"hello": "world"}');
+  req.end();
+});
+
+
 test('tear down', function(t) {
   server.on('close', function() {
     t.end();