util: Fix the size of sorted_displays allocation

As sorted_displays is a vector containing all displays' order, its
allocation size must be the maximum display id + 1 instead of the
maximum display id. Also, fix the size used for sorting and iterating
the sorted_displays vector.

Valgrind log:
==15946== Invalid write of size 4
==15946==    at 0x4169C0: virt_viewer_align_monitors_linear (virt-viewer-util.c:581)
==15946==    by 0x42248B: virt_viewer_session_on_monitor_geometry_changed (virt-viewer-session.c:438)
==15946==    by 0xBB41F03: _g_closure_invoke_va (gclosure.c:831)
==15946==    by 0xBB5BC7C: g_signal_emit_valist (gsignal.c:3214)
==15946==    by 0xBB5C764: g_signal_emit_by_name (gsignal.c:3401)
==15946==    by 0x4328F3: virt_viewer_display_spice_monitor_geometry_changed (virt-viewer-display-spice.c:93)
==15946==    by 0x432D60: virt_viewer_display_spice_size_allocate (virt-viewer-display-spice.c:224)
==15946==    by 0xBB41CD4: g_closure_invoke (gclosure.c:768)
==15946==    by 0xBB53538: signal_emit_unlocked_R (gsignal.c:3549)
==15946==    by 0xBB5BEEF: g_signal_emit_valist (gsignal.c:3305)
==15946==    by 0xBB5C29E: g_signal_emit (gsignal.c:3361)
==15946==    by 0x637D6F6: gtk_widget_size_allocate_with_baseline (gtkwidget.c:6093)
==15946==  Address 0x18c79d4c is 0 bytes after a block of size 12 alloc'd
==15946==    at 0x4C2A9C7: calloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==15946==    by 0xBDD36D1: g_malloc0 (gmem.c:127)
==15946==    by 0x41698D: virt_viewer_align_monitors_linear (virt-viewer-util.c:577)
==15946==    by 0x42248B: virt_viewer_session_on_monitor_geometry_changed (virt-viewer-session.c:438)
==15946==    by 0xBB41F03: _g_closure_invoke_va (gclosure.c:831)
==15946==    by 0xBB5BC7C: g_signal_emit_valist (gsignal.c:3214)
==15946==    by 0xBB5C764: g_signal_emit_by_name (gsignal.c:3401)
==15946==    by 0x4328F3: virt_viewer_display_spice_monitor_geometry_changed (virt-viewer-display-spice.c:93)
==15946==    by 0x432D60: virt_viewer_display_spice_size_allocate (virt-viewer-display-spice.c:224)
==15946==    by 0xBB41CD4: g_closure_invoke (gclosure.c:768)
==15946==    by 0xBB53538: signal_emit_unlocked_R (gsignal.c:3549)
==15946==    by 0xBB5BEEF: g_signal_emit_valist (gsignal.c:3305)

Resolves: rhbz#1272650
Related: rhbz#1267184

1 files changed, 7 insertions, 4 deletions

diff --git a/src/virt-viewer-util.c b/src/virt-viewer-util.c
index e9f771b..f2ccd13 100644
--- a/src/virt-viewer-util.c
+++ b/src/virt-viewer-util.c
@@ -565,6 +565,7 @@ virt_viewer_align_monitors_linear(GHashTable *displays)
     gint i, x = 0;
     guint *sorted_displays;
     guint max_id = 0;
+    guint ndisplays = 0;
     GHashTableIter iter;
     gpointer key, value;
 
@@ -574,19 +575,21 @@ virt_viewer_align_monitors_linear(GHashTable *displays)
         return;
 
     g_hash_table_foreach(displays, find_max_id, &max_id);
-    sorted_displays = g_new0(guint, max_id);
+    ndisplays = max_id + 1;
+
+    sorted_displays = g_new0(guint, ndisplays);
 
     g_hash_table_iter_init(&iter, displays);
     while (g_hash_table_iter_next(&iter, &key, &value))
         sorted_displays[GPOINTER_TO_INT(key)] = GPOINTER_TO_INT(key);
 
-    g_qsort_with_data(sorted_displays, max_id, sizeof(guint), displays_cmp, displays);
+    g_qsort_with_data(sorted_displays, ndisplays, sizeof(guint), displays_cmp, displays);
 
     /* adjust monitor positions so that there's no gaps or overlap between
      * monitors */
-    for (i = 0; i < max_id; i++) {
+    for (i = 0; i < ndisplays; i++) {
         guint nth = sorted_displays[i];
-        g_assert(nth < max_id);
+        g_assert(nth < ndisplays);
         GdkRectangle *rect = g_hash_table_lookup(displays, GINT_TO_POINTER(nth));
         rect->x = x;
         rect->y = 0;