X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=plugins%2FOStatus%2Flib%2Fmagicenvelope.php;h=9e02f5eab5e3f8963ae7020bb3223058a86f8498;hb=1e89540c3f52f95e9224d781c01b2c927d3c3f09;hp=487435927d4e8616db427db858d3dc3e43db6ef6;hpb=d594c83a5a9a9d42fce917b544c28591fcadb1aa;p=quix0rs-gnu-social.git

diff --git a/plugins/OStatus/lib/magicenvelope.php b/plugins/OStatus/lib/magicenvelope.php
index 487435927d..9e02f5eab5 100644
--- a/plugins/OStatus/lib/magicenvelope.php
+++ b/plugins/OStatus/lib/magicenvelope.php
@@ -32,51 +32,110 @@ class MagicEnvelope
 
     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 $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) {
+        if (!empty($xml)) {
+            $dom = DOMDocument::loadXML($xml);
+            if (!$dom instanceof DOMDocument) {
+                throw new ServerException('Tried to load malformed XML as DOM');
+            } elseif (!$this->fromDom($dom)) {
+                throw new ServerException('Could not load MagicEnvelope from DOM');
+            }
         }
+    }
 
-        if (strpos($user_id, '@') !== FALSE) {
-            return 'acct:' . $user_id;
+    /**
+     * 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) {
+        $magicsig = Magicsig::getKV('user_id', $profile->id);
+
+        if ($discovery && !$magicsig instanceof Magicsig) {
+            // Throws exception on failure, but does not try to _load_ the keypair string.
+            $keypair = $this->discoverKeyPair($profile);
+
+            $magicsig = new Magicsig();
+            $magicsig->user_id = $profile->id;
+            $magicsig->importKeys($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->id));
+        }
+
         $disco = new Discovery();
 
-        try {
-            $xrd = $disco->lookup($signer_uri);
-        } catch (Exception $e) {
-            return false;
+        // Throws exception on lookup problems
+        $xrd = $disco->lookup($signer_uri);
+
+        $link = $xrd->get(Magicsig::PUBLICKEYREL);
+        if (is_null($link)) {
+            // TRANS: Exception.
+            throw new Exception(_m('Unable to locate signer public key.'));
         }
-        if ($xrd->links) {
-            if ($link = Discovery::getService($xrd->links, Magicsig::PUBLICKEYREL)) {
-                $keypair = false;
-                $parts = explode(',', $link['href']);
-                if (count($parts) == 2) {
-                    $keypair = $parts[1];
-                } else {
-                    // Backwards compatibility check for separator bug in 0.9.0
-                    $parts = explode(';', $link['href']);
-                    if (count($parts) == 2) {
-                        $keypair = $parts[1];
-                    }
-                }
-
-                if ($keypair) {
-                    return $keypair;
-                }
+
+        // We have a public key element, let's hope it has proper key data.
+        $keypair = false;
+        $parts = explode(',', $link->href);
+        if (count($parts) == 2) {
+            $keypair = $parts[1];
+        } else {
+            // Backwards compatibility check for separator bug in 0.9.0
+            $parts = explode(';', $link->href);
+            if (count($parts) == 2) {
+                $keypair = $parts[1];
             }
         }
-        // TRANS: Exception.
-        throw new Exception(_m('Unable to locate signer public key.'));
+
+        if ($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;
     }
 
     /**
@@ -84,135 +143,121 @@ class MagicEnvelope
      * includes both the original data and some signing metadata fields as
      * the input plaintext for the signature hash.
      *
-     * @param array $env
      * @return string
      */
-    public function signingText($env) {
-        return implode('.', array($env['data'], // this field is pre-base64'd
-                            Magicsig::base64_url_encode($env['data_type']),
-                            Magicsig::base64_url_encode($env['encoding']),
-                            Magicsig::base64_url_encode($env['alg'])));
+    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)));
     }
 
     /**
      *
      * @param <type> $text
      * @param <type> $mimetype
-     * @param <type> $keypair
-     * @return array: associative array of envelope properties
-     * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
+     * @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, $keypair)
+    public function signMessage($text, $mimetype, Magicsig $magicsig)
     {
-        $signature_alg = Magicsig::fromString($keypair);
-        $armored_text = Magicsig::base64_url_encode($text);
-        $env = array(
-            'data' => $armored_text,
-            'encoding' => MagicEnvelope::ENCODING,
-            'data_type' => $mimetype,
-            'sig' => '',
-            'alg' => $signature_alg->getName()
-        );
-
-        $env['sig'] = $signature_alg->sign($this->signingText($env));
-
-        return $env;
+        assert($magicsig->privateKey instanceof Crypt_RSA);
+
+        // 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());
     }
 
     /**
      * Create an <me:env> XML representation of the envelope.
      *
-     * @param array $env associative array with envelope data
      * @return string representation of XML document
-     * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
      */
-    public function toXML($env) {
+    public function toXML() {
         $xs = new XMLStringer();
         $xs->startXML();
-        $xs->elementStart('me:env', array('xmlns:me' => MagicEnvelope::NS));
-        $xs->element('me:data', array('type' => $env['data_type']), $env['data']);
-        $xs->element('me:encoding', null, $env['encoding']);
-        $xs->element('me:alg', null, $env['alg']);
-        $xs->element('me:sig', null, $env['sig']);
+        $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');
 
         $string =  $xs->getString();
-        common_debug($string);
         return $string;
     }
 
-    /**
+    /*
      * Extract the contained XML payload, and insert a copy of the envelope
      * signature data as an <me:provenance> section.
      *
-     * @param array $env associative array with envelope data
-     * @return string representation of modified XML document
+     * @return DOMDocument of Atom entry
      *
      * @fixme in case of XML parsing errors, this will spew to the error log or output
-     * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
      */
-    public function unfold($env)
+    public function getPayload()
     {
         $dom = new DOMDocument();
-        $dom->loadXML(Magicsig::base64_url_decode($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);
-
-        $dom->documentElement->appendChild($prov);
-
-        return $dom->saveXML();
+    public function getSignature()
+    {
+        return $this->sig;
     }
 
     /**
-     * Find the author URI referenced in the given Atom entry.
-     *
-     * @param string $text string containing Atom entry XML
-     * @return mixed URI string or false if XML parsing fails, or null if no author URI can be found
+     * Find the author URI referenced in the payload Atom entry.
      *
-     * @fixme XML parsing failures will spew to error logs/output
+     * @return string URI for author
+     * @throws ServerException on failure
      */
-    public function getAuthor($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 getAuthorUri() {
+        $doc = $this->getPayload();
+
+        $authors = $doc->documentElement->getElementsByTagName('author');
+        foreach ($authors as $author) {
+            $uris = $author->getElementsByTagName('uri');
+            foreach ($uris as $uri) {
+                return $uri->nodeValue;
             }
         }
-    }
-
-    /**
-     * Check if the author in the Atom entry fragment claims to match
-     * the given identifier URI.
-     *
-     * @param string $text string containing Atom entry XML
-     * @param string $signer_uri
-     * @return boolean
-     */
-    public function checkAuthor($text, $signer_uri)
-    {
-        return ($this->getAuthor($text) == $signer_uri);
+        throw new ServerException('No author URI found in Salmon payload data');
     }
 
     /**
@@ -221,58 +266,31 @@ class MagicEnvelope
      *
      * Details of failure conditions are dumped to output log and not exposed to caller.
      *
-     * @param array $env array representation of magic envelope data, as returned from MagicEnvelope::parse()
-     * @return boolean
+     * @param Profile $profile profile used to get locally cached public signature key
+     *                         or if necessary perform discovery on.
      *
-     * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
+     * @return boolean
      */
-    public function verify($env)
+    public function verify(Profile $profile)
     {
-        if ($env['alg'] != 'RSA-SHA256') {
+        if ($this->alg != 'RSA-SHA256') {
             common_log(LOG_DEBUG, "Salmon error: bad algorithm");
             return false;
         }
 
-        if ($env['encoding'] != MagicEnvelope::ENCODING) {
+        if ($this->encoding != self::ENCODING) {
             common_log(LOG_DEBUG, "Salmon error: bad encoding");
             return false;
         }
 
-        $text = Magicsig::base64_url_decode($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());
             return false;
         }
 
-        $verifier = Magicsig::fromString($keypair);
-
-        if (!$verifier) {
-            common_log(LOG_DEBUG, "Salmon error: unable to parse keypair");
-            return false;
-        }
-
-        return $verifier->verify($this->signingText($env), $env['sig']);
-    }
-
-    /**
-     * Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
-     *
-     * @param string XML source
-     * @return mixed associative array of envelope data, or false on unrecognized input
-     *
-     * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
-     * @fixme will spew errors to logs or output in case of XML parse errors
-     * @fixme may give fatal errors if some elements are missing or invalid XML
-     * @fixme calling DOMDocument::loadXML statically triggers warnings in strict mode
-     */
-    public function parse($text)
-    {
-        $dom = DOMDocument::loadXML($text);
-        return $this->fromDom($dom);
+        return $magicsig->verify($this->signingText(), $this->getSignature());
     }
 
     /**
@@ -281,48 +299,60 @@ class MagicEnvelope
      * @param DOMDocument $dom
      * @return mixed associative array of envelope data, or false on unrecognized input
      *
-     * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
      * @fixme may give fatal errors if some elements are missing
      */
-    public function fromDom($dom)
+    protected function fromDom(DOMDocument $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);
-        $sig_element = $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'sig')->item(0);
-        return array(
-            'data' => preg_replace('/\s/', '', $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' => preg_replace('/\s/', '', $sig_element->nodeValue),
-        );
-    }
-}
+        $data_element = $env_element->getElementsByTagNameNS(self::NS, 'data')->item(0);
+        $sig_element = $env_element->getElementsByTagNameNS(self::NS, 'sig')->item(0);
 
-/**
- * Variant of MagicEnvelope using the earlier signature form listed in the MagicEnvelope
- * spec in early 2010; this was used in StatusNet up through 0.9.6, so for backwards compatiblity
- * we still need to accept and sometimes send this format.
- */
-class MagicEnvelopeCompat extends MagicEnvelope {
+        $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;
+    }
 
     /**
-     * StatusNet through 0.9.6 used an earlier version of the MagicEnvelope spec
-     * which used only the input data, without the additional fields, as the plaintext
-     * for signing.
+     * 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.
      *
-     * @param array $env
-     * @return string
+     * 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 $text
+     *
+     * @return MagicEnvelope object complete with signature
+     *
+     * @throws Exception on bad profile input or key generation problems
      */
-    public function signingText($env) {
-        return $env['data'];
+    public static function signAsUser($text, User $user)
+    {
+        // Find already stored key
+        $magicsig = Magicsig::getKV('user_id', $user->id);
+        if (!$magicsig instanceof Magicsig) {
+            $magicsig = Magicsig::generate($user);
+        }
+        assert($magicsig instanceof Magicsig);
+        assert($magicsig->privateKey instanceof Crypt_RSA);
+
+        $magic_env = new MagicEnvelope();
+        $magic_env->signMessage($text, 'application/atom+xml', $magicsig);
+
+        return $magic_env;
     }
 }