Bug 24333

Summary:	Call dbus_g_proxy_disconnect_signal() with an "almost-freed" parameter
Product:	Telepathy	Reporter:	Alban Crequy <alban.crequy>
Component:	tp-glib	Assignee:	Telepathy bugs list <telepathy-bugs>
Status:	RESOLVED MOVED	QA Contact:	Telepathy bugs list <telepathy-bugs>
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Alban Crequy 2009-10-05 13:57:24 UTC

telepathy-glib/proxy-signals.c tp_proxy_signal_connection_disconnect_dbus_glib() line 87:
>  dbus_g_proxy_disconnect_signal (iface_proxy, sc->member,
>      sc->collect_args, (gpointer) sc);


The variable sc->member is not freed before the call but it will be freed during the call by this stack:

==9440==    at 0x4024866: free (vg_replace_malloc.c:325)
==9440==    by 0x5C26FE5: g_free (gmem.c:190)
==9440==    by 0x4366828: tp_proxy_signal_connection_unref (proxy-signals.c:174)
==9440==    by 0x5BAD932: g_closure_unref (gclosure.c:254)
==9440==    by 0x5BC3C50: signal_handlers_foreach_matched_R (gsignal.c:637)
==9440==    by 0x5BC3E15: g_signal_handlers_disconnect_matched (gsignal.c:2673)
==9440==    by 0x425926E: dbus_g_proxy_disconnect_signal (dbus-gproxy.c:3033)

It means the implementation of dbus_g_proxy_disconnect_signal() cannot read its parameter "signal_name" after the signal disconnection although the parameter is supposedly "const".

It is not a problem with the current version of dbus-glib because it does not read the parameter after the disconnection. But it is surprising, I think tp-glib should not give a parameter that it is going to free before the end of the call.

I found this problem while hacking on Bug #23846.

Comment 1 GitLab Migration User 2019-12-03 19:23:41 UTC

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