From afff2b15e89ac81c113f2ebfd729aaa02b40edb6 Mon Sep 17 00:00:00 2001
From: Kirill Batuzov <batuzovk@ispras.ru>
Date: Thu, 24 Apr 2014 18:15:58 +0400
Subject: console: Abort on property access errors

All defined properties of QemuConsole are mandatory and no access to them
should fail. Nevertheless not checking returned errors is bad because in case
of unexpected failure it will hide the bug and cause a memory leak.

Abort in case of unexpected property access errors. This change exposed a bug
where an attempt was made to write to a read-only property "head".

Set "head" property's value at creation time and do not attempt to change it
later. This fixes the bug mentioned above.

Signed-off-by: Kirill Batuzov <batuzovk@ispras.ru>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 ui/console.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

(limited to 'ui')

diff --git a/ui/console.c b/ui/console.c
index 34d1eaa..c92df8b 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1167,9 +1167,9 @@ static void text_console_update(void *opaque, console_ch_t *chardata)
     }
 }
 
-static QemuConsole *new_console(DisplayState *ds, console_type_t console_type)
+static QemuConsole *new_console(DisplayState *ds, console_type_t console_type,
+                                uint32_t head)
 {
-    Error *local_err = NULL;
     Object *obj;
     QemuConsole *s;
     int i;
@@ -1179,13 +1179,14 @@ static QemuConsole *new_console(DisplayState *ds, console_type_t console_type)
 
     obj = object_new(TYPE_QEMU_CONSOLE);
     s = QEMU_CONSOLE(obj);
+    s->head = head;
     object_property_add_link(obj, "device", TYPE_DEVICE,
                              (Object **)&s->device,
                              object_property_allow_set_link,
                              OBJ_PROP_LINK_UNREF_ON_RELEASE,
-                             &local_err);
+                             &error_abort);
     object_property_add_uint32_ptr(obj, "head",
-                                   &s->head, &local_err);
+                                   &s->head, &error_abort);
 
     if (!active_console || ((active_console->console_type != GRAPHIC_CONSOLE) &&
         (console_type == GRAPHIC_CONSOLE))) {
@@ -1560,7 +1561,6 @@ static DisplayState *get_alloc_displaystate(void)
  */
 DisplayState *init_displaystate(void)
 {
-    Error *local_err = NULL;
     gchar *name;
     int i;
 
@@ -1579,7 +1579,7 @@ DisplayState *init_displaystate(void)
          * doesn't change any more */
         name = g_strdup_printf("console[%d]", i);
         object_property_add_child(container_get(object_get_root(), "/backend"),
-                                  name, OBJECT(consoles[i]), &local_err);
+                                  name, OBJECT(consoles[i]), &error_abort);
         g_free(name);
     }
 
@@ -1590,7 +1590,6 @@ QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
                                   const GraphicHwOps *hw_ops,
                                   void *opaque)
 {
-    Error *local_err = NULL;
     int width = 640;
     int height = 480;
     QemuConsole *s;
@@ -1598,14 +1597,12 @@ QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
 
     ds = get_alloc_displaystate();
     trace_console_gfx_new();
-    s = new_console(ds, GRAPHIC_CONSOLE);
+    s = new_console(ds, GRAPHIC_CONSOLE, head);
     s->hw_ops = hw_ops;
     s->hw = opaque;
     if (dev) {
-        object_property_set_link(OBJECT(s), OBJECT(dev),
-                                 "device", &local_err);
-        object_property_set_int(OBJECT(s), head,
-                                "head", &local_err);
+        object_property_set_link(OBJECT(s), OBJECT(dev), "device",
+                                 &error_abort);
     }
 
     s->surface = qemu_create_displaysurface(width, height);
@@ -1622,7 +1619,6 @@ QemuConsole *qemu_console_lookup_by_index(unsigned int index)
 
 QemuConsole *qemu_console_lookup_by_device(DeviceState *dev, uint32_t head)
 {
-    Error *local_err = NULL;
     Object *obj;
     uint32_t h;
     int i;
@@ -1632,12 +1628,12 @@ QemuConsole *qemu_console_lookup_by_device(DeviceState *dev, uint32_t head)
             continue;
         }
         obj = object_property_get_link(OBJECT(consoles[i]),
-                                       "device", &local_err);
+                                       "device", &error_abort);
         if (DEVICE(obj) != dev) {
             continue;
         }
         h = object_property_get_int(OBJECT(consoles[i]),
-                                    "head", &local_err);
+                                    "head", &error_abort);
         if (h != head) {
             continue;
         }
@@ -1811,9 +1807,9 @@ static CharDriverState *text_console_init(ChardevVC *vc)
 
     trace_console_txt_new(width, height);
     if (width == 0 || height == 0) {
-        s = new_console(NULL, TEXT_CONSOLE);
+        s = new_console(NULL, TEXT_CONSOLE, 0);
     } else {
-        s = new_console(NULL, TEXT_CONSOLE_FIXED_SIZE);
+        s = new_console(NULL, TEXT_CONSOLE_FIXED_SIZE, 0);
         s->surface = qemu_create_displaysurface(width, height);
     }
 
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