From 3721027edb2d2f6f71cf655d643f7796864cfdbc Mon Sep 17 00:00:00 2001
From: Marvin W <git@larma.de>
Date: Mon, 20 Mar 2023 15:37:18 -0600
Subject: Improve history sync

- Ensure we fully fetch desired history if possible (previously, duplicates
  from offline message queue could hinder MAM sync)
- Early drop illegal MAM messages so they don't pile up in the pending queue
  waiting for their query to end (which it never will if they were not
  requested in first place).

Fixes #1386
---
 .../xep/0313_message_archive_management.vala       | 46 ++++++++++++++++++----
 1 file changed, 38 insertions(+), 8 deletions(-)

(limited to 'xmpp-vala/src/module/xep')

diff --git a/xmpp-vala/src/module/xep/0313_message_archive_management.vala b/xmpp-vala/src/module/xep/0313_message_archive_management.vala
index 1caa1bc3..2235e118 100644
--- a/xmpp-vala/src/module/xep/0313_message_archive_management.vala
+++ b/xmpp-vala/src/module/xep/0313_message_archive_management.vala
@@ -11,8 +11,8 @@ public class QueryResult {
     public bool error { get; set; default=false; }
     public bool malformed { get; set; default=false; }
     public bool complete { get; set; default=false; }
-    public string first { get; set; }
-    public string last { get; set; }
+    public string? first { get; set; }
+    public string? last { get; set; }
 }
 
 public class Module : XmppStreamModule {
@@ -65,16 +65,17 @@ public class Module : XmppStreamModule {
         }
 
         StanzaNode query_node = new StanzaNode.build("query", NS_VER(stream)).add_self_xmlns().put_node(data_form.get_submit_node());
-        if (queryid != null) {
-            query_node.put_attribute("queryid", queryid);
-        }
+        query_node.put_attribute("queryid", queryid);
         return query_node;
     }
 
     internal async QueryResult query_archive(XmppStream stream, string ns, Jid? mam_server, StanzaNode query_node, Cancellable? cancellable = null) {
-        var res = new QueryResult();
 
-        if (stream.get_flag(Flag.IDENTITY) == null) { res.error = true; return res; }
+        var res = new QueryResult();
+        Flag? flag = stream.get_flag(Flag.IDENTITY);
+        string? query_id = query_node.get_attribute("queryid");
+        if (flag == null || query_id == null) { res.error = true; return res; }
+        flag.active_query_ids.add(query_id);
 
         // Build and send query
         Iq.Stanza iq = new Iq.Stanza.set(query_node) { to=mam_server };
@@ -93,6 +94,11 @@ public class Module : XmppStreamModule {
         if ((res.first == null) != (res.last == null)) { res.malformed = true; return res; }
         res.complete = fin_node.get_attribute_bool("complete", false, ns);
 
+        Idle.add(() => {
+            flag.active_query_ids.remove(query_id);
+            return Source.REMOVE;
+        }, Priority.LOW);
+
         return res;
     }
 
@@ -104,7 +110,8 @@ public class ReceivedPipelineListener : StanzaListener<MessageStanza> {
     public override string[] after_actions { get { return after_actions_const; } }
 
     public override async bool run(XmppStream stream, MessageStanza message) {
-        if (stream.get_flag(Flag.IDENTITY) == null) return false;
+        Flag? flag = stream.get_flag(Flag.IDENTITY);
+        if (flag == null) return false;
 
         StanzaNode? message_node = message.stanza.get_deep_subnode(NS_VER(stream) + ":result", StanzaForwarding.NS_URI + ":forwarded", Xmpp.NS_URI + ":message");
         if (message_node != null) {
@@ -112,6 +119,28 @@ public class ReceivedPipelineListener : StanzaListener<MessageStanza> {
             DateTime? datetime = DelayedDelivery.get_time_for_node(forward_node);
             string? mam_id = message.stanza.get_deep_attribute(NS_VER(stream) + ":result", NS_VER(stream) + ":id");
             string? query_id = message.stanza.get_deep_attribute(NS_VER(stream) + ":result", NS_VER(stream) + ":queryid");
+
+            if (query_id == null) {
+                warning("Received MAM message without queryid from %s, ignoring", message.from.to_string());
+                return true;
+            }
+
+            if (!flag.active_query_ids.contains(query_id)) {
+                warning("Received MAM message from %s with unknown query id %s, ignoring", message.from.to_string(), query_id ?? "<none>");
+                return true;
+            }
+            Jid? inner_from = null;
+            try {
+                inner_from = new Jid(message_node.get_attribute("from"));
+            } catch (InvalidJidError e) {
+                warning("Received MAM message with invalid from attribute in forwarded message from %s, ignoring", message.from.to_string());
+                return true;
+            }
+            if (!message.from.equals(stream.get_flag(Bind.Flag.IDENTITY).my_jid.bare_jid) && !message.from.equals_bare(inner_from)) {
+                warning("Received MAM message from %s illegally impersonating %s, ignoring", message.from.to_string(), inner_from.to_string());
+                return true;
+            }
+
             message.add_flag(new MessageFlag(message.from, datetime, mam_id, query_id));
 
             message.stanza = message_node;
@@ -124,6 +153,7 @@ public class ReceivedPipelineListener : StanzaListener<MessageStanza> {
 public class Flag : XmppStreamFlag {
     public static FlagIdentity<Flag> IDENTITY = new FlagIdentity<Flag>(NS_URI, "message_archive_management");
     public bool cought_up { get; set; default=false; }
+    public Gee.Set<string> active_query_ids { get; set; default = new HashSet<string>(); }
     public string ns_ver;
 
     public Flag(string ns_ver) {
-- 
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