From 7c9415356db372663545c997794a370387383d0c Mon Sep 17 00:00:00 2001
From: Evgeniy Khramtsov <ekhramtsov@process-one.net>
Date: Tue, 18 Apr 2017 01:38:35 +0300
Subject: [PATCH] Function fix_from_to/2 should not crash when 'from' is
 undefined

Fixes #1678
---
 src/ejabberd_c2s.erl | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/ejabberd_c2s.erl b/src/ejabberd_c2s.erl
index c1f1e2fa5..e0a10e659 100644
--- a/src/ejabberd_c2s.erl
+++ b/src/ejabberd_c2s.erl
@@ -867,13 +867,17 @@ get_conn_type(State) ->
 -spec fix_from_to(xmpp_element(), state()) -> stanza().
 fix_from_to(Pkt, #{jid := JID}) when ?is_stanza(Pkt) ->
     #jid{luser = U, lserver = S, lresource = R} = JID,
-    From = xmpp:get_from(Pkt),
-    From1 = case jid:tolower(From) of
-		{U, S, R} -> JID;
-		{U, S, _} -> jid:replace_resource(JID, From#jid.resource);
-		_ -> From
-	    end,
-    xmpp:set_from_to(Pkt, From1, JID);
+    case xmpp:get_from(Pkt) of
+	undefined ->
+	    Pkt;
+	From ->
+	    From1 = case jid:tolower(From) of
+			{U, S, R} -> JID;
+			{U, S, _} -> jid:replace_resource(JID, From#jid.resource);
+			_ -> From
+		    end,
+	    xmpp:set_from_to(Pkt, From1, JID)
+    end;
 fix_from_to(Pkt, _State) ->
     Pkt.