[evolution-data-server] Bug 634294 - Calendar factory crash under e-cal-recur

[Milan Crha <mcrha src gnome org>]

commit f5b6da9e44436ba14f36c9797417c4c89315d4ed
Author: Milan Crha <mcrha redhat com>
Date:   Fri Jun 17 13:53:18 2016 +0200

    Bug 634294 - Calendar factory crash under e-cal-recur

 calendar/libecal/e-cal-recur.c |   48 ++++++++++++++++++++--------------------
 1 files changed, 24 insertions(+), 24 deletions(-)
---
diff --git a/calendar/libecal/e-cal-recur.c b/calendar/libecal/e-cal-recur.c
index b86caf3..b2b9893 100644
--- a/calendar/libecal/e-cal-recur.c
+++ b/calendar/libecal/e-cal-recur.c
@@ -190,7 +190,14 @@ ensure_timezone (icalcomponent *comp,
        if (g_cancellable_set_error_if_cancelled (cancellable, error))
                return FALSE;
 
-       if (!tt || tt->zone || tt->is_utc)
+       if (!tt)
+               return TRUE;
+
+       /* Do not trust the 'zone' set on the structure, as it can come from
+          a different icalcomponent and cause use-after-free. */
+       tt->zone = NULL;
+
+       if (tt->is_utc || tt->is_date)
                return TRUE;
 
        if (!prop)
@@ -344,10 +351,8 @@ e_cal_recur_generate_instances_sync (icalcomponent *comp,
        times = g_hash_table_new_full (e_instance_time_hash, e_instance_time_equal, g_free, NULL);
 
        dtstart = icalcomponent_get_dtstart (comp);
-       if (!dtstart.is_date) {
-               success = ensure_timezone (comp, &dtstart, ICAL_DTSTART_PROPERTY, NULL,
-                       get_tz_callback, get_tz_callback_user_data, default_timezone, cancellable, error);
-       }
+       success = ensure_timezone (comp, &dtstart, ICAL_DTSTART_PROPERTY, NULL,
+               get_tz_callback, get_tz_callback_user_data, default_timezone, cancellable, error);
 
        duration_seconds = 0;
        dtend = icalcomponent_get_dtend (comp);
@@ -388,9 +393,8 @@ e_cal_recur_generate_instances_sync (icalcomponent *comp,
        }
 
        if (success && !icaltime_is_null_time (dtend)) {
-               if (!dtend.is_date)
-                       success = ensure_timezone (comp, &dtend, ICAL_DTEND_PROPERTY, NULL,
-                               get_tz_callback, get_tz_callback_user_data, default_timezone, cancellable, 
error);
+               success = ensure_timezone (comp, &dtend, ICAL_DTEND_PROPERTY, NULL,
+                       get_tz_callback, get_tz_callback_user_data, default_timezone, cancellable, error);
                duration_seconds = (gint64) icaltime_as_timet_with_zone (dtend, dtend.zone) -
                        (gint64) icaltime_as_timet_with_zone (dtstart, dtstart.zone);
                if (duration_seconds < 0)
@@ -412,7 +416,7 @@ e_cal_recur_generate_instances_sync (icalcomponent *comp,
                        struct icalrecurrencetype rrule = icalproperty_get_rrule (prop);
                        icalrecur_iterator *riter;
 
-                       if (!icaltime_is_null_time (rrule.until) && !rrule.until.is_date) {
+                       if (!icaltime_is_null_time (rrule.until)) {
                                success = ensure_timezone (comp, &rrule.until, 0, prop,
                                        get_tz_callback, get_tz_callback_user_data, (icaltimezone *) 
dtstart.zone,
                                        cancellable, error);
@@ -501,13 +505,11 @@ e_cal_recur_generate_instances_sync (icalcomponent *comp,
                        }
 
                        if (!icaltime_is_null_time (tt)) {
-                               if (!tt.is_date) {
-                                       success = ensure_timezone (comp, &tt, 0, prop,
-                                               get_tz_callback, get_tz_callback_user_data, (icaltimezone *) 
dtstart.zone,
-                                               cancellable, error);
-                                       if (!success)
-                                               break;
-                               }
+                               success = ensure_timezone (comp, &tt, 0, prop,
+                                       get_tz_callback, get_tz_callback_user_data, (icaltimezone *) 
dtstart.zone,
+                                       cancellable, error);
+                               if (!success)
+                                       break;
 
                                if (intersects_interval (&tt, &duration, duration_days, duration_seconds, 
&interval_start, &interval_end)) {
                                        g_hash_table_insert (times, e_instance_time_new (&tt, &duration), 
NULL);
@@ -521,7 +523,7 @@ e_cal_recur_generate_instances_sync (icalcomponent *comp,
                        struct icalrecurrencetype exrule = icalproperty_get_exrule (prop);
                        icalrecur_iterator *riter;
 
-                       if (!icaltime_is_null_time (exrule.until) && !exrule.until.is_date) {
+                       if (!icaltime_is_null_time (exrule.until)) {
                                success = ensure_timezone (comp, &exrule.until, 0, prop,
                                        get_tz_callback, get_tz_callback_user_data, (icaltimezone *) 
dtstart.zone,
                                        cancellable, error);
@@ -575,13 +577,11 @@ e_cal_recur_generate_instances_sync (icalcomponent *comp,
                        if (icaltime_is_null_time (exdate))
                                continue;
 
-                       if (!exdate.is_date) {
-                               success = ensure_timezone (comp, &exdate, 0, prop,
-                                       get_tz_callback, get_tz_callback_user_data, (icaltimezone *) 
dtstart.zone,
-                                       cancellable, error);
-                               if (!success)
-                                       break;
-                       }
+                       success = ensure_timezone (comp, &exdate, 0, prop,
+                               get_tz_callback, get_tz_callback_user_data, (icaltimezone *) dtstart.zone,
+                               cancellable, error);
+                       if (!success)
+                               break;
 
                        if (!exdate.zone)
                                exdate.zone = dtstart.zone;