* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
* @link http://status.net/
*/
-
class MagicEnvelope
{
const ENCODING = 'base64url';
const NS = 'http://salmon-protocol.org/ns/magic-env';
-
- private function normalizeUser($user_id)
- {
- if (substr($user_id, 0, 5) == 'http:' ||
- substr($user_id, 0, 6) == 'https:' ||
- substr($user_id, 0, 5) == 'acct:') {
- return $user_id;
+
+ protected $actor = null; // Profile of user who has signed the envelope
+
+ protected $data = null; // When stored here it is _always_ base64url encoded
+ protected $data_type = null;
+ protected $encoding = null;
+ protected $alg = null;
+ protected $sig = null;
+
+ /**
+ * Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
+ *
+ * @param string XML source
+ * @return mixed associative array of envelope data, or false on unrecognized input
+ *
+ * @fixme will spew errors to logs or output in case of XML parse errors
+ * @fixme may give fatal errors if some elements are missing or invalid XML
+ * @fixme calling DOMDocument::loadXML statically triggers warnings in strict mode
+ */
+ public function __construct($xml=null, Profile $actor=null) {
+ if (!empty($xml)) {
+ $dom = new DOMDocument();
+ if (!$dom->loadXML($xml)) {
+ throw new ServerException('Tried to load malformed XML as DOM');
+ } elseif (!$this->fromDom($dom)) {
+ throw new ServerException('Could not load MagicEnvelope from DOM');
+ }
+ } elseif ($actor instanceof Profile) {
+ // So far we only allow setting with _either_ $xml _or_ $actor as that's
+ // all our circumstances require. But it may be confusing for new developers.
+ // The idea is that feeding XML must be followed by interpretation and then
+ // running $magic_env->verify($profile), just as in SalmonAction->prepare(...)
+ // and supplying an $actor (which right now has to be a User) will require
+ // defining the $data, $data_type etc. attributes manually afterwards before
+ // signing the envelope..
+ $this->setActor($actor);
}
+ }
+
+ /**
+ * Retrieve Salmon keypair first by checking local database, but
+ * if it's not found, attempt discovery if it has been requested.
+ *
+ * @param Profile $profile The profile we're looking up keys for.
+ * @param boolean $discovery Network discovery if no local cache?
+ */
+ public function getKeyPair(Profile $profile, $discovery=false) {
+ if (!$profile->isLocal()) common_debug('Getting magic-public-key for non-local profile id=='.$profile->getID());
+ $magicsig = Magicsig::getKV('user_id', $profile->getID());
+
+ if ($discovery && !$magicsig instanceof Magicsig) {
+ if (!$profile->isLocal()) common_debug('magic-public-key not found, will do discovery for profile id=='.$profile->getID());
+ // Throws exception on failure, but does not try to _load_ the keypair string.
+ $keypair = $this->discoverKeyPair($profile);
- if (strpos($user_id, '@') !== FALSE) {
- return 'acct:' . $user_id;
+ $magicsig = new Magicsig();
+ $magicsig->user_id = $profile->getID();
+ $magicsig->importKeys($keypair);
+ // save the public key for this profile in our database.
+ // TODO: If the profile generates a new key remotely, we must be able to replace
+ // this (of course after callback-verification).
+ $magicsig->insert();
+ } elseif (!$magicsig instanceof Magicsig) { // No discovery request, so we'll give up.
+ throw new ServerException(sprintf('No public key found for profile (id==%d)', $profile->id));
}
- return 'http://' . $user_id;
+ assert($magicsig->publicKey instanceof Crypt_RSA);
+
+ return $magicsig;
}
- public function getKeyPair($signer_uri)
+ /**
+ * Get the Salmon keypair from a URI, uses XRD Discovery etc. Reasonably
+ * you'll only get the public key ;)
+ *
+ * The string will (hopefully) be formatted as described in Magicsig specification:
+ * https://salmon-protocol.googlecode.com/svn/trunk/draft-panzer-magicsig-01.html#anchor13
+ *
+ * @return string formatted as Magicsig keypair
+ */
+ public function discoverKeyPair(Profile $profile)
{
+ $signer_uri = $profile->getUri();
+ if (empty($signer_uri)) {
+ throw new ServerException(sprintf('Profile missing URI (id==%d)', $profile->getID()));
+ }
+
$disco = new Discovery();
+ // Throws exception on lookup problems
try {
$xrd = $disco->lookup($signer_uri);
} catch (Exception $e) {
- return false;
+ // Diaspora seems to require us to request the acct: uri
+ $xrd = $disco->lookup($profile->getAcctUri());
}
- if ($xrd->links) {
- if ($link = Discovery::getService($xrd->links, Magicsig::PUBLICKEYREL)) {
- list($type, $keypair) = explode(',', $link['href']);
- if (empty($keypair)) {
- // Backwards compatibility check for separator bug in 0.9.0
- list($type, $keypair) = explode(';', $link['href']);
- }
- return $keypair;
+
+ common_debug('Will try to find magic-public-key from XRD of profile id=='.$profile->getID());
+ $pubkey = null;
+ if (Event::handle('MagicsigPublicKeyFromXRD', array($xrd, &$pubkey))) {
+ $link = $xrd->get(Magicsig::PUBLICKEYREL);
+ if (is_null($link)) {
+ // TRANS: Exception.
+ throw new Exception(_m('Unable to locate signer public key.'));
+ }
+ $pubkey = $link->href;
+ }
+ if (empty($pubkey)) {
+ throw new ServerException('Empty Magicsig public key. A bug?');
+ }
+
+ // We have a public key element, let's hope it has proper key data.
+ $keypair = false;
+ $parts = explode(',', $pubkey);
+ if (count($parts) == 2) {
+ $keypair = $parts[1];
+ } else {
+ // Backwards compatibility check for separator bug in 0.9.0
+ $parts = explode(';', $pubkey);
+ if (count($parts) == 2) {
+ $keypair = $parts[1];
}
}
- throw new Exception('Unable to locate signer public key');
+
+ if ($keypair === false) {
+ // For debugging clarity. Keypair did not pass count()-check above.
+ // TRANS: Exception when public key was not properly formatted.
+ throw new Exception(_m('Incorrectly formatted public key element.'));
+ }
+
+ return $keypair;
}
+ /**
+ * The current MagicEnvelope spec as used in StatusNet 0.9.7 and later
+ * includes both the original data and some signing metadata fields as
+ * the input plaintext for the signature hash.
+ *
+ * @return string
+ */
+ public function signingText() {
+ return implode('.', array($this->data, // this field is pre-base64'd
+ Magicsig::base64_url_encode($this->data_type),
+ Magicsig::base64_url_encode($this->encoding),
+ Magicsig::base64_url_encode($this->alg)));
+ }
- public function signMessage($text, $mimetype, $keypair)
+ /**
+ *
+ * @param <type> $text
+ * @param <type> $mimetype
+ * @param Magicsig $magicsig Magicsig with private key available.
+ *
+ * @return MagicEnvelope object with all properties set
+ *
+ * @throws Exception of various kinds on signing failure
+ */
+ public function signMessage($text, $mimetype)
{
- $signature_alg = Magicsig::fromString($keypair);
- $armored_text = base64_url_encode($text);
+ if (!$this->actor instanceof Profile) {
+ throw new ServerException('No profile to sign message with is set.');
+ } elseif (!$this->actor->isLocal()) {
+ throw new ServerException('Cannot sign magic envelopes with remote users since we have no private key.');
+ }
- return array(
- 'data' => $armored_text,
- 'encoding' => MagicEnvelope::ENCODING,
- 'data_type' => $mimetype,
- 'sig' => $signature_alg->sign($armored_text),
- 'alg' => $signature_alg->getName()
- );
-
-
- }
+ // Find already stored key
+ $magicsig = Magicsig::getKV('user_id', $this->actor->getID());
+ if (!$magicsig instanceof Magicsig) {
+ // and if it doesn't exist, it is time to create one!
+ $magicsig = Magicsig::generate($this->actor->getUser());
+ }
+ assert($magicsig instanceof Magicsig);
+ assert($magicsig->privateKey instanceof Crypt_RSA);
- public function toXML($env) {
- $dom = new DOMDocument();
+ // Prepare text and metadata for signing
+ $this->data = Magicsig::base64_url_encode($text);
+ $this->data_type = $mimetype;
+ $this->encoding = self::ENCODING;
+ $this->alg = $magicsig->getName();
+
+ // Get the actual signature
+ $this->sig = $magicsig->sign($this->signingText());
+ }
- $envelope = $dom->createElementNS(MagicEnvelope::NS, 'me:env');
- $envelope->setAttribute('xmlns:me', MagicEnvelope::NS);
- $data = $dom->createElementNS(MagicEnvelope::NS, 'me:data', $env['data']);
- $data->setAttribute('type', $env['data_type']);
- $envelope->appendChild($data);
- $enc = $dom->createElementNS(MagicEnvelope::NS, 'me:encoding', $env['encoding']);
- $envelope->appendChild($enc);
- $alg = $dom->createElementNS(MagicEnvelope::NS, 'me:alg', $env['alg']);
- $envelope->appendChild($alg);
- $sig = $dom->createElementNS(MagicEnvelope::NS, 'me:sig', $env['sig']);
- $envelope->appendChild($sig);
+ /**
+ * Create an <me:env> XML representation of the envelope.
+ *
+ * @return string representation of XML document
+ */
+ public function toXML(Profile $target=null, $flavour=null) {
+ $xs = new XMLStringer();
+ $xs->startXML(); // header, to point out it's not HTML or anything...
+ if (Event::handle('StartMagicEnvelopeToXML', array($this, $xs, $flavour, $target))) {
+ // fall back to our default, normal Magic Envelope XML.
+ // the $xs element _may_ have had elements added, or could get in the end event
+ $xs->elementStart('me:env', array('xmlns:me' => self::NS));
+ $xs->element('me:data', array('type' => $this->data_type), $this->data);
+ $xs->element('me:encoding', null, $this->encoding);
+ $xs->element('me:alg', null, $this->alg);
+ $xs->element('me:sig', null, $this->getSignature());
+ $xs->elementEnd('me:env');
- $dom->appendChild($envelope);
-
-
- return $dom->saveXML();
+ Event::handle('EndMagicEnvelopeToXML', array($this, $xs, $flavour, $target));
+ }
+ return $xs->getString();
}
-
- public function unfold($env)
+ /*
+ * Extract the contained XML payload, and insert a copy of the envelope
+ * signature data as an <me:provenance> section.
+ *
+ * @return DOMDocument of Atom entry
+ *
+ * @fixme in case of XML parsing errors, this will spew to the error log or output
+ */
+ public function getPayload()
{
$dom = new DOMDocument();
- $dom->loadXML(base64_url_decode($env['data']));
+ if (!$dom->loadXML(Magicsig::base64_url_decode($this->data))) {
+ throw new ServerException('Malformed XML in Salmon payload');
+ }
- if ($dom->documentElement->tagName != 'entry') {
- return false;
+ switch ($this->data_type) {
+ case 'application/atom+xml':
+ if ($dom->documentElement->namespaceURI !== Activity::ATOM
+ || $dom->documentElement->tagName !== 'entry') {
+ throw new ServerException(_m('Salmon post must be an Atom entry.'));
+ }
+ $prov = $dom->createElementNS(self::NS, 'me:provenance');
+ $prov->setAttribute('xmlns:me', self::NS);
+ $data = $dom->createElementNS(self::NS, 'me:data', $this->data);
+ $data->setAttribute('type', $this->data_type);
+ $prov->appendChild($data);
+ $enc = $dom->createElementNS(self::NS, 'me:encoding', $this->encoding);
+ $prov->appendChild($enc);
+ $alg = $dom->createElementNS(self::NS, 'me:alg', $this->alg);
+ $prov->appendChild($alg);
+ $sig = $dom->createElementNS(self::NS, 'me:sig', $this->getSignature());
+ $prov->appendChild($sig);
+
+ $dom->documentElement->appendChild($prov);
+ break;
+ default:
+ throw new ServerException('Unknown Salmon payload data type');
}
+ return $dom;
+ }
- $prov = $dom->createElementNS(MagicEnvelope::NS, 'me:provenance');
- $prov->setAttribute('xmlns:me', MagicEnvelope::NS);
- $data = $dom->createElementNS(MagicEnvelope::NS, 'me:data', $env['data']);
- $data->setAttribute('type', $env['data_type']);
- $prov->appendChild($data);
- $enc = $dom->createElementNS(MagicEnvelope::NS, 'me:encoding', $env['encoding']);
- $prov->appendChild($enc);
- $alg = $dom->createElementNS(MagicEnvelope::NS, 'me:alg', $env['alg']);
- $prov->appendChild($alg);
- $sig = $dom->createElementNS(MagicEnvelope::NS, 'me:sig', $env['sig']);
- $prov->appendChild($sig);
+ public function getSignature()
+ {
+ if (empty($this->sig)) {
+ throw new ServerException('You must first call signMessage before getSignature');
+ }
+ return $this->sig;
+ }
- $dom->documentElement->appendChild($prov);
+ public function getSignatureAlgorithm()
+ {
+ return $this->alg;
+ }
- return $dom->saveXML();
+ public function getData()
+ {
+ return $this->data;
}
-
- public function getAuthor($text) {
- $doc = new DOMDocument();
- if (!$doc->loadXML($text)) {
- return FALSE;
- }
-
- if ($doc->documentElement->tagName == 'entry') {
- $authors = $doc->documentElement->getElementsByTagName('author');
- foreach ($authors as $author) {
- $uris = $author->getElementsByTagName('uri');
- foreach ($uris as $uri) {
- return $this->normalizeUser($uri->nodeValue);
- }
- }
- }
+
+ public function getDataType()
+ {
+ return $this->data_type;
}
-
- public function checkAuthor($text, $signer_uri)
+
+ public function getEncoding()
{
- return ($this->getAuthor($text) == $signer_uri);
+ return $this->encoding;
}
-
- public function verify($env)
+
+ /**
+ * Find the author URI referenced in the payload Atom entry.
+ *
+ * @return string URI for author
+ * @throws ServerException on failure
+ */
+ public function getAuthorUri() {
+ $doc = $this->getPayload();
+
+ $authors = $doc->documentElement->getElementsByTagName('author');
+ foreach ($authors as $author) {
+ $uris = $author->getElementsByTagName('uri');
+ foreach ($uris as $uri) {
+ return $uri->nodeValue;
+ }
+ }
+ throw new ServerException('No author URI found in Salmon payload data');
+ }
+
+ /**
+ * Attempt to verify cryptographic signing for parsed envelope data.
+ * Requires network access to retrieve public key referenced by the envelope signer.
+ *
+ * Details of failure conditions are dumped to output log and not exposed to caller.
+ *
+ * @param Profile $profile profile used to get locally cached public signature key
+ * or if necessary perform discovery on.
+ *
+ * @return boolean
+ */
+ public function verify(Profile $profile)
{
- if ($env['alg'] != 'RSA-SHA256') {
- common_log(LOG_DEBUG, "Salmon error: bad algorithm");
+ if ($this->alg != 'RSA-SHA256') {
+ common_debug("Salmon error: bad algorithm");
return false;
}
- if ($env['encoding'] != MagicEnvelope::ENCODING) {
- common_log(LOG_DEBUG, "Salmon error: bad encoding");
+ if ($this->encoding != self::ENCODING) {
+ common_debug("Salmon error: bad encoding");
return false;
}
- $text = base64_url_decode($env['data']);
- $signer_uri = $this->getAuthor($text);
-
try {
- $keypair = $this->getKeyPair($signer_uri);
+ $magicsig = $this->getKeyPair($profile, true); // Do discovery too if necessary
} catch (Exception $e) {
- common_log(LOG_DEBUG, "Salmon error: ".$e->getMessage());
+ common_debug("Salmon error: ".$e->getMessage());
return false;
}
-
- $verifier = Magicsig::fromString($keypair);
- if (!$verifier) {
- common_log(LOG_DEBUG, "Salmon error: unable to parse keypair");
- return false;
+ if (!$magicsig->verify($this->signingText(), $this->getSignature())) {
+ // TRANS: Client error when incoming salmon slap signature does not verify cryptographically.
+ throw new ClientException(_m('Salmon signature verification failed.'));
}
-
- return $verifier->verify($env['data'], $env['sig']);
+ $this->setActor($profile);
+ return true;
}
- public function parse($text)
+ /**
+ * Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
+ *
+ * @param DOMDocument $dom
+ * @return mixed associative array of envelope data, or false on unrecognized input
+ *
+ * @fixme may give fatal errors if some elements are missing
+ */
+ protected function fromDom(DOMDocument $dom)
{
- $dom = DOMDocument::loadXML($text);
- return $this->fromDom($dom);
- }
-
- public function fromDom($dom)
- {
- $env_element = $dom->getElementsByTagNameNS(MagicEnvelope::NS, 'env')->item(0);
+ $env_element = $dom->getElementsByTagNameNS(self::NS, 'env')->item(0);
if (!$env_element) {
- $env_element = $dom->getElementsByTagNameNS(MagicEnvelope::NS, 'provenance')->item(0);
+ $env_element = $dom->getElementsByTagNameNS(self::NS, 'provenance')->item(0);
}
if (!$env_element) {
return false;
}
- $data_element = $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'data')->item(0);
-
- return array(
- 'data' => trim($data_element->nodeValue),
- 'data_type' => $data_element->getAttribute('type'),
- 'encoding' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'encoding')->item(0)->nodeValue,
- 'alg' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'alg')->item(0)->nodeValue,
- 'sig' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'sig')->item(0)->nodeValue,
- );
+ $data_element = $env_element->getElementsByTagNameNS(self::NS, 'data')->item(0);
+ $sig_element = $env_element->getElementsByTagNameNS(self::NS, 'sig')->item(0);
+
+ $this->data = preg_replace('/\s/', '', $data_element->nodeValue);
+ $this->data_type = $data_element->getAttribute('type');
+ $this->encoding = $env_element->getElementsByTagNameNS(self::NS, 'encoding')->item(0)->nodeValue;
+ $this->alg = $env_element->getElementsByTagNameNS(self::NS, 'alg')->item(0)->nodeValue;
+ $this->sig = preg_replace('/\s/', '', $sig_element->nodeValue);
+ return true;
+ }
+
+ public function setActor(Profile $actor)
+ {
+ if ($this->actor instanceof Profile) {
+ throw new ServerException('Cannot set a new actor profile for MagicEnvelope object.');
+ }
+ $this->actor = $actor;
+ }
+
+ public function getActor()
+ {
+ if (!$this->actor instanceof Profile) {
+ throw new ServerException('No actor set for this magic envelope.');
+ }
+ return $this->actor;
}
+ /**
+ * Encode the given string as a signed MagicEnvelope XML document,
+ * using the keypair for the given local user profile. We can of
+ * course not sign a remote profile's slap, since we don't have the
+ * private key.
+ *
+ * Side effects: will create and store a keypair on-demand if one
+ * hasn't already been generated for this user. This can be very slow
+ * on some systems.
+ *
+ * @param string $text XML fragment to sign, assumed to be Atom
+ * @param User $user User who cryptographically signs $text
+ *
+ * @return MagicEnvelope object complete with signature
+ *
+ * @throws Exception on bad profile input or key generation problems
+ */
+ public static function signAsUser($text, User $user)
+ {
+ $magic_env = new MagicEnvelope(null, $user->getProfile());
+ $magic_env->signMessage($text, 'application/atom+xml');
+
+ return $magic_env;
+ }
}
projects / quix0rs-gnu-social.git / blobdiff