xfce4-session crashes at startup if session-screenshot is enabled

Submitted by Landry Breuil @landry

Assigned to Xfce Bug Triage

Link to original bug (#6885)

Description

bt:

#0  0x00000002111e9924 in strlen () from /usr/lib/libc.so.58.0
#1  0x0000000200fabc84 in g_strconcat () from /usr/local/lib/libglib-2.0.so.2600.0
#2  0x000000000010fb18 in xfsm_load_session_preview (name=0x212b725f0 "Default") at xfsm-global.c:154
#3  0x0000000000112380 in xfsm_manager_restart (manager=0x205f5a030) at xfsm-manager.c:764
#4  0x000000000010a1f0 in main (argc=1, argv=0xffffffffffff82e8) at main.c:265

#2  0x000000000010fb18 in xfsm_load_session_preview (name=0x212b725f0 "Default") at xfsm-global.c:154
154       resource = g_strconcat ("sessions/thumbs-", display_name,
(gdb) p display_name
$2 = (gchar *) 0x13176ae0 <Address 0x13176ae0 out of bounds>

152       display = gdk_display_get_default ();
153       display_name = xfsm_gdk_display_get_fullname (display);

for some reason display_name contains garbage, and code doesn't check for it.

solution.. either fix the code, or disable/remove it, as some consider it has security concerns...

Version: 4.7.1