[evolution-ews] Crash when meeting invitation iCalendar part could not be parsed

[Milan Crha <mcrha src gnome org>]

commit f497204167969702e571c1781c2440e918938895
Author: Milan Crha <mcrha redhat com>
Date:   Wed Apr 18 10:50:34 2018 +0200

    Crash when meeting invitation iCalendar part could not be parsed
    
    Reported downstream at:
    https://bugzilla.redhat.com/show_bug.cgi?id=1565343

 src/camel/camel-ews-folder.c |   65 ++++++++++++++++++++++++------------------
 1 files changed, 37 insertions(+), 28 deletions(-)
---
diff --git a/src/camel/camel-ews-folder.c b/src/camel/camel-ews-folder.c
index cc1c266..2c0079e 100644
--- a/src/camel/camel-ews-folder.c
+++ b/src/camel/camel-ews-folder.c
@@ -398,9 +398,8 @@ ews_update_mgtrequest_mime_calendar_itemid (const gchar *mime_fname,
                CamelDataWrapper *dw;
                CamelStream *tmpstream = NULL, *newstream = NULL;
                GByteArray *ba;
-               icalcomponent *icalcomp, *subcomp;
-               icalproperty *icalprop;
-               gchar *calstring_new, *dir;
+               icalcomponent *icalcomp = NULL;
+               gchar *dir;
                gint fd;
                gboolean success = FALSE;
 
@@ -412,33 +411,43 @@ ews_update_mgtrequest_mime_calendar_itemid (const gchar *mime_fname,
                        goto exit_msg;
                }
                ba = camel_stream_mem_get_byte_array (CAMEL_STREAM_MEM (tmpstream));
-               g_byte_array_append (ba, (guint8 *) "\0", 1);
-               icalcomp = icalparser_parse_string ((gchar *) ba->data);
-               subcomp = icalcomponent_get_first_component (icalcomp, ICAL_VEVENT_COMPONENT);
-               icalprop = icalproperty_new_x (calendar_item_id->change_key);
-               icalproperty_set_x_name (icalprop, "X-EVOLUTION-CHANGEKEY");
-
-               /* In order to accept items we have to store AssociatedCalendarItemId (X-EVOLUTION-ITEMID)
-                * or mail id (X-EVOLUTION-ACCEPT-ID) when we do not have AssociatedCalendarItemId */
-               icalcomponent_add_property (subcomp, icalprop);
-               if (is_calendar_UID) {
-                       icalprop = icalproperty_new_x (calendar_item_id->id);
-                       icalproperty_set_x_name (icalprop, "X-EVOLUTION-ITEMID");
-                       icalcomponent_add_property (subcomp, icalprop);
+               if (ba && ba->len) {
+                       g_byte_array_append (ba, (guint8 *) "\0", 1);
+                       icalcomp = icalparser_parse_string ((gchar *) ba->data);
                }
+               if (icalcomp) {
+                       icalcomponent *subcomp;
+                       icalproperty *icalprop;
+                       gchar *calstring_new;
+
+                       subcomp = icalcomponent_get_first_component (icalcomp, ICAL_VEVENT_COMPONENT);
+                       icalprop = icalproperty_new_x (calendar_item_id->change_key);
+                       icalproperty_set_x_name (icalprop, "X-EVOLUTION-CHANGEKEY");
+
+                       /* In order to accept items we have to store AssociatedCalendarItemId 
(X-EVOLUTION-ITEMID)
+                        * or mail id (X-EVOLUTION-ACCEPT-ID) when we do not have AssociatedCalendarItemId */
+                       icalcomponent_add_property (subcomp, icalprop);
+                       if (is_calendar_UID) {
+                               icalprop = icalproperty_new_x (calendar_item_id->id);
+                               icalproperty_set_x_name (icalprop, "X-EVOLUTION-ITEMID");
+                               icalcomponent_add_property (subcomp, icalprop);
+                       }
 
-               icalprop = icalproperty_new_x (mail_item_id->id);
-               icalproperty_set_x_name (icalprop, "X-EVOLUTION-ACCEPT-ID");
-               icalcomponent_add_property (subcomp, icalprop);
-
-               calstring_new = icalcomponent_as_ical_string_r (icalcomp);
-               camel_mime_part_set_content (
-                       mimepart,
-                       (const gchar *) calstring_new,
-                       strlen (calstring_new),
-                       "text/calendar");
-               g_free (calstring_new);
-               icalcomponent_free (icalcomp);
+                       icalprop = icalproperty_new_x (mail_item_id->id);
+                       icalproperty_set_x_name (icalprop, "X-EVOLUTION-ACCEPT-ID");
+                       icalcomponent_add_property (subcomp, icalprop);
+
+                       calstring_new = icalcomponent_as_ical_string_r (icalcomp);
+                       if (calstring_new) {
+                               camel_mime_part_set_content (
+                                       mimepart,
+                                       (const gchar *) calstring_new,
+                                       strlen (calstring_new),
+                                       "text/calendar");
+                               g_free (calstring_new);
+                       }
+                       icalcomponent_free (icalcomp);
+               }
                g_object_unref (tmpstream);
 
                /* Create a new file to store updated mimecontent */