From e001c86b4a41f9e950a899b8215b1d69fb7841ed Mon Sep 17 00:00:00 2001
From: Mike Macgirvin <mike@macgirvin.com>
Date: Sun, 16 Jun 2024 08:55:21 +1000
Subject: [PATCH] rework delivery permissions to allow sender, owner, and
 mentions

---
 include/items.php       |  2 +-
 include/permissions.php | 60 ++++++++++++++++++++++++++++++++---------
 src/Daemon/Notifier.php |  6 ++---
 3 files changed, 51 insertions(+), 17 deletions(-)

diff --git a/include/items.php b/include/items.php
index b7f796390..b1690c9eb 100644
--- a/include/items.php
+++ b/include/items.php
@@ -125,7 +125,7 @@ function collect_recipients($item, &$private_envelope) {
     // This is a somewhat expensive operation but important.
     // Don't send this item to anybody who doesn't have the deliver_stream permission
 
-    $recipients = check_deliver_permissions($item['uid'],$recipients);
+    $recipients = check_deliver_permissions($item,$recipients);
 
     // Add both the author and owner (if different).
 
diff --git a/include/permissions.php b/include/permissions.php
index 548df0627..abaeb998e 100644
--- a/include/permissions.php
+++ b/include/permissions.php
@@ -515,9 +515,11 @@ function check_list_permissions($uid, $arr, $perm)
     return($result);
 }
 
-function check_deliver_permissions($uid, $arr)
+function check_deliver_permissions($item, $arr)
 {
     $result = [];
+    $uid = $item['uid'] ?? 0;
+    $terms = ((isset($item['term'])) ? get_terms_oftype($item['term'], [TERM_MENTION, TERM_GROUP]) : false);
     // Find actors we are not delivering to.
     $r = q("select * from abconfig where chan = %d and cat = 'system' and k = 'my_perms' and v not like '%%deliver_stream%%'",
         intval($uid)
@@ -533,27 +535,59 @@ function check_deliver_permissions($uid, $arr)
 
     // Filter the recipient list accordingly.
     if ($arr) {
-        foreach ($arr as $x) {
+        foreach ($arr as $recipient) {
             $accepting = $deliverable = false;
-            if (in_array($x, $theyAccept)) {
+            if (in_array($recipient, $theyAccept)) {
                 $accepting = true;
             }
-            if (!in_array($x,$willNotSend)) {
+            if (!in_array($recipient,$willNotSend)) {
                 $deliverable = true;
             }
-            if ($deliverable && !$accepting) {
+            if (in_array($recipient, [$item['author_xchan'], $item['owner_xchan']])) {
+                $deliverable = $accepting = true;
+            }
+            if (!$deliverable || !$accepting) {
                 // Groups don't generally provide send_stream permission as they aren't really following you,
                 // but they do allow you to send them group targeted posts.
-                $r = q("select xchan_hash from xchan where xchan_hash = '%s' and xchan_type = %d ",
-                    dbesc($x),
-                    intval(XCHAN_TYPE_GROUP)
-                );
-                if ($r) {
-                    $result[] = $x;
+                if ($deliverable) {
+                    $r = q("select xchan_hash from xchan where xchan_hash = '%s' and xchan_type = %d",
+                        dbesc($recipient),
+                        intval(XCHAN_TYPE_GROUP)
+                    );
+                    if ($r) {
+                        if ($r && !in_array($recipient, $result)) {
+                            $result[] = $recipient;
+                            continue;
+                        }
+                    }
+                }
+                // Send mentions even if you have no permission to do so. They might allow it.
+                if ($terms) {
+                    foreach ($terms as $term) {
+                        if (in_array($term['url'], $result)) {
+                            continue;
+                        }
+                        // activitypub is easy because $x will match directly on the mention url
+                        if ($recipient === $term['url'] && (!in_array($recipient, $result))) {
+                            $result[] = $recipient;
+                            break;
+                        }
+                        // zot/nomad is harder because we will need to match the portable_id to the mention url
+                        // and won't be able to perform duplicate detection
+                        $r = q("select hubloc_id from hubloc where hubloc_hash = '%s' and hubloc_id_url = '%s' and hubloc_deleted = 0",
+                            dbesc($recipient),
+                            dbesc($term['url'])
+                        );
+                        if ($r && !in_array($recipient, $result)) {
+                            $result[] = $recipient;
+                            break;
+                        }
+                    }
                 }
             }
-            if ($deliverable && $accepting) {
-                $result[] = $x;
+
+            if ($deliverable && $accepting && !in_array($recipient, $result)) {
+                $result[] = $recipient;
             }
         }
     }
diff --git a/src/Daemon/Notifier.php b/src/Daemon/Notifier.php
index 975093eca..9c4242240 100644
--- a/src/Daemon/Notifier.php
+++ b/src/Daemon/Notifier.php
@@ -444,7 +444,7 @@ class Notifier implements DaemonInterface
                 else {
                     $sendto = array_merge($sendto, self::getConversationAudience($parent_item));
                 }
-                self::$recipients = check_deliver_permissions($target_item['uid'], $sendto);
+                self::$recipients = check_deliver_permissions($target_item, $sendto);
                 logger('followup relay (upstream delivery)', LOGGER_DEBUG);
                 logger('replyto: upstream recipients ' . print_r(self::$recipients, true), LOGGER_DEBUG);
 
@@ -497,7 +497,7 @@ class Notifier implements DaemonInterface
                         foreach ($r as $rv) {
                             self::$recipients[] = $rv['abook_xchan'];
                         }
-                        self::$recipients = check_deliver_permissions($target_item['uid'], self::$recipients);
+                        self::$recipients = check_deliver_permissions($target_item, self::$recipients);
                     }
                 }
                 elseif (($audience & AUDIENCE_SENDER) || ($audience & AUDIENCE_FOLLOWERS)
@@ -524,7 +524,7 @@ class Notifier implements DaemonInterface
                             }
                         }
                     }
-                    self::$recipients = check_deliver_permissions($target_item['uid'], $sendto);
+                    self::$recipients = check_deliver_permissions($target_item, $sendto);
                 }
                 else {
                     self::$private = false;