[gnome-shell] polkitAgent: Disconnect session signal handlers when destroying session

[Florian Müllner <fmuellner src gnome org>]

commit 5f223e0bd87aa93e5d68dc53766c0cfbbb063a26
Author: Philip Withnall <withnall endlessm com>
Date:   Fri Jan 18 13:19:32 2019 +0000

    polkitAgent: Disconnect session signal handlers when destroying session
    
    Otherwise the session could outlive the dialogue, emit a subsequent
    signal, and its callback would reference finalised objects/widgets from
    the dialogue. The PolkitSession object is implemented by
    libpolkit-gobject, so we have no guarantees about its reference counting
    — the session object could keep itself alive in another thread, or be a
    singleton. In all likelihood, the session hangs around for longer than
    the dialogue due to differences in when the two objects are garbage
    collected.
    
    This can be triggered by running `pkexec true` from a gnome-terminal
    window, then calling `pkill pkexec` from another terminal (on a
    different VT or via SSH). This causes the dialogue to be cancelled by
    polkitd.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/357

 js/ui/components/polkitAgent.js | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)
---
diff --git a/js/ui/components/polkitAgent.js b/js/ui/components/polkitAgent.js
index 4b2a2cacb..4ea4efba4 100644
--- a/js/ui/components/polkitAgent.js
+++ b/js/ui/components/polkitAgent.js
@@ -169,10 +169,10 @@ var AuthenticationDialog = new Lang.Class({
         this.destroySession();
         this._session = new PolkitAgent.Session({ identity: this._identityToAuth,
                                                   cookie: this._cookie });
-        this._session.connect('completed', this._onSessionCompleted.bind(this));
-        this._session.connect('request', this._onSessionRequest.bind(this));
-        this._session.connect('show-error', this._onSessionShowError.bind(this));
-        this._session.connect('show-info', this._onSessionShowInfo.bind(this));
+        this._sessionCompletedId = this._session.connect('completed', this._onSessionCompleted.bind(this));
+        this._sessionRequestId = this._session.connect('request', this._onSessionRequest.bind(this));
+        this._sessionShowErrorId = this._session.connect('show-error', this._onSessionShowError.bind(this));
+        this._sessionShowInfoId = this._session.connect('show-info', this._onSessionShowInfo.bind(this));
         this._session.initiate();
     },
 
@@ -311,6 +311,11 @@ var AuthenticationDialog = new Lang.Class({
             if (!this._completed)
                 this._session.cancel();
             this._completed = false;
+
+            this._session.disconnect(this._sessionCompletedId);
+            this._session.disconnect(this._sessionRequestId);
+            this._session.disconnect(this._sessionShowErrorId);
+            this._session.disconnect(this._sessionShowInfoId);
             this._session = null;
         }
     },