From 0d7971739587df80c82efaf3cc7932875b5e8c43 Mon Sep 17 00:00:00 2001
From: Christophe Fergeau <cfergeau@redhat.com>
Date: Tue, 9 Sep 2014 18:00:30 +0200
Subject: [PATCH] Validate surface bounding box before using it
It's possible for a buggy guest driver to pass invalid bounding box
dimensions in QXL commands, which would then cause spice-server to
segfault. This patch checks the size of the bounding box of the QXL
command right after it has been parsed.
This fixes rhbz#1135372
(cherry picked from commit e270edcbfd958d764e84cdbca6d403ff24fef610)
---
server/red_worker.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/server/red_worker.c b/server/red_worker.c
index 945f4f1..9e6a6ad 100644
--- a/server/red_worker.c
+++ b/server/red_worker.c
@@ -1272,6 +1272,33 @@ static inline void __validate_surface(RedWorker *worker, uint32_t surface_id)
spice_warn_if(surface_id >= worker->n_surfaces);
}
+static int validate_drawable_bbox(RedWorker *worker, RedDrawable *drawable)
+{
+ DrawContext *context;
+ uint32_t surface_id = drawable->surface_id;
+
+ /* surface_id must be validated before calling into
+ * validate_drawable_bbox
+ */
+ __validate_surface(worker, surface_id);
+ context = &worker->surfaces[surface_id].context;
+
+ if (drawable->bbox.top < 0)
+ return FALSE;
+ if (drawable->bbox.left < 0)
+ return FALSE;
+ if (drawable->bbox.bottom < 0)
+ return FALSE;
+ if (drawable->bbox.right < 0)
+ return FALSE;
+ if (drawable->bbox.bottom > context->height)
+ return FALSE;
+ if (drawable->bbox.right > context->width)
+ return FALSE;
+
+ return TRUE;
+}
+
static inline int validate_surface(RedWorker *worker, uint32_t surface_id)
{
spice_warn_if(surface_id >= worker->n_surfaces);
@@ -4117,6 +4144,10 @@ static Drawable *get_drawable(RedWorker *worker, uint8_t effect, RedDrawable *re
VALIDATE_SURFACE_RETVAL(worker, drawable->surfaces_dest[x], NULL)
}
}
+ if (!validate_drawable_bbox(worker, red_drawable)) {
+ rendering_incorrect(__func__);
+ return NULL;
+ }
ring_init(&drawable->pipes);
ring_init(&drawable->glz_ring);