Hi Marc-Andre,
On 07/18/2012 02:15 PM, Marc-André Lureau wrote:
Limit range of monitors, to avoid potential crashes lead by invalid
received MonitorConfig values (could be misconfigured or misbehaving
guest)
This is a a client-side implementation limitation. Eventually, the
range could be inscreased (or unlimited == 0) in the future...
To me, it seems safer to just ignore such messages.
If the values of config->max_allowed or config->count are wrong why
do you trust config->heads ?
But since the patch does provide a little bit safer spice-gtk, ack.
---
gtk/channel-display.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/gtk/channel-display.c b/gtk/channel-display.c
index d77447a..72d2c12 100644
--- a/gtk/channel-display.c
+++ b/gtk/channel-display.c
@@ -59,6 +59,8 @@
#define SPICE_DISPLAY_CHANNEL_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE((obj), SPICE_TYPE_DISPLAY_CHANNEL, SpiceDisplayChannelPrivate))
+#define MONITORS_MAX 256
+
struct _SpiceDisplayChannelPrivate {
Ring surfaces;
display_cache *images;
@@ -275,7 +277,7 @@ static void spice_display_channel_class_init(SpiceDisplayChannelClass *klass)
g_param_spec_uint("monitors-max",
"Max display monitors",
"The current maximum number of monitors",
- 1, G_MAXINT16, 1,
+ 1, MONITORS_MAX, 1,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS));
@@ -1493,6 +1495,8 @@ static void display_handle_surface_destroy(SpiceChannel *channel, SpiceMsgIn *in
free(surface);
}
+#define CLAMP_CHECK(x, low, high) (((x)> (high)) ? TRUE : (((x)< (low)) ? TRUE : FALSE))
+
/* coroutine context */
static void display_handle_monitors_config(SpiceChannel *channel, SpiceMsgIn *in)
{
@@ -1506,6 +1510,16 @@ static void display_handle_monitors_config(SpiceChannel *channel, SpiceMsgIn *in
SPICE_DEBUG("monitors config: n: %d/%d", config->count, config->max_allowed);
c->monitors_max = config->max_allowed;
+ if (CLAMP_CHECK(c->monitors_max, 1, MONITORS_MAX)) {
+ g_warning("MonitorConfig max_allowed is not within permitted range, clamping");
+ c->monitors_max = CLAMP(c->monitors_max, 1, MONITORS_MAX);
+ }
+
+ if (CLAMP_CHECK(config->count, 1, c->monitors_max)) {
+ g_warning("MonitorConfig count is not within permitted range, clamping");
+ config->count = CLAMP(config->count, 1, c->monitors_max);
+ }
+
c->monitors = g_array_set_size(c->monitors, config->count);
for (i = 0; i< config->count; i++) {
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