From 411f3b86a45eeaef0df493393cf9b4149d3335fc Mon Sep 17 00:00:00 2001
From: Mikael Nordfeldth <mmn@hethane.se>
Date: Sat, 31 May 2014 12:51:51 +0200
Subject: [PATCH] Use locally cached Salmon keys for profiles

Please note that we're not yet actually caching them ourselves.
---
 plugins/OStatus/lib/magicenvelope.php | 35 ++++++++++++++++++++++++---
 plugins/OStatus/lib/salmonaction.php  | 19 ++++++++++++---
 2 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/plugins/OStatus/lib/magicenvelope.php b/plugins/OStatus/lib/magicenvelope.php
index 9990053904..1a4abb5e1b 100644
--- a/plugins/OStatus/lib/magicenvelope.php
+++ b/plugins/OStatus/lib/magicenvelope.php
@@ -59,12 +59,33 @@ class MagicEnvelope
         }
     }
 
+    /**
+     * 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) {
+            $signer_uri = $profile->getUri();
+            if (empty($signer_uri)) {
+                throw new ServerException(sprintf('Profile missing URI (id==%d)', $profile->id));
+            }
+            $magicsig = $this->discoverKeyPair($signer_uri);
+        } 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 $magicsig;
+    }
+
     /**
      * Get the Salmon keypair from a URI, uses XRD Discovery etc.
      *
      * @return Magicsig with loaded keypair
      */
-    public function getKeyPair($signer_uri)
+    public function discoverKeyPair($signer_uri)
     {
         $disco = new Discovery();
 
@@ -228,9 +249,11 @@ class MagicEnvelope
      *
      * Details of failure conditions are dumped to output log and not exposed to caller.
      *
+     * @param Profile $profile optional profile used to get locally cached public signature key.
+     *
      * @return boolean
      */
-    public function verify()
+    public function verify(Profile $profile=null)
     {
         if ($this->alg != 'RSA-SHA256') {
             common_log(LOG_DEBUG, "Salmon error: bad algorithm");
@@ -243,8 +266,12 @@ class MagicEnvelope
         }
 
         try {
-            $signer_uri = $this->getAuthorUri();
-            $magicsig = $this->getKeyPair($signer_uri);
+            if ($profile instanceof Profile) {
+                $magicsig = $this->getKeyPair($profile, true);    // Do discovery too if necessary
+            } else {
+                $signer_uri = $this->getAuthorUri();
+                $magicsig = $this->discoverKeyPair($signer_uri);
+            }
         } catch (Exception $e) {
             common_log(LOG_DEBUG, "Salmon error: ".$e->getMessage());
             return false;
diff --git a/plugins/OStatus/lib/salmonaction.php b/plugins/OStatus/lib/salmonaction.php
index 4366822ffd..6e44ff2eb6 100644
--- a/plugins/OStatus/lib/salmonaction.php
+++ b/plugins/OStatus/lib/salmonaction.php
@@ -28,6 +28,8 @@ class SalmonAction extends Action
 {
     protected $needPost = true;
 
+    protected $verified = false;
+
     var $xml      = null;
     var $activity = null;
     var $target   = null;
@@ -45,15 +47,24 @@ class SalmonAction extends Action
 
         $envxml = file_get_contents('php://input');
         $magic_env = new MagicEnvelope($envxml);   // parse incoming XML as a MagicEnvelope
-        if (!$magic_env->verify()) {
+
+        $entry = $magic_env->getPayload();  // Not cryptographically verified yet!
+        $this->activity = new Activity($entry->documentElement);
+
+        try {
+            $profile = Profile::fromUri($this->activity->actor->id);
+            $this->verified = $magic_env->verify($profile);
+        } catch (UnknownUriException $e) {
+            // If we don't know the profile, perform some discovery instead
+            $this->verified = $magic_env->verify();
+        }
+
+        if (!$this->verified) {
             common_log(LOG_DEBUG, "Salmon signature verification failed.");
             // TRANS: Client error.
             $this->clientError(_m('Salmon signature verification failed.'));
         }
 
-        $entry = $magic_env->getPayload();
-
-        $this->activity = new Activity($entry->documentElement);
         return true;
     }