File 0133-virtio-gpu-check-early-scanout-id.patch of Package qemu.5749

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File 0133-virtio-gpu-check-early-scanout-id.patch of Package qemu.5749

From 6656e418ba5a61a0cfdd930147b2af562f8b902e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
Date: Thu, 19 May 2016 12:25:55 +0200
Subject: [PATCH] virtio-gpu: check early scanout id
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Before accessing the g->scanout array, in order to avoid potential
out-of-bounds access.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 1463653560-26958-2-git-send-email-marcandre.lureau@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/virtio-gpu.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 4ccc8bc5c3..10e3ae2fab 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -512,6 +512,14 @@ static void virtio_gpu_set_scanout(VirtIOGPU *g,
     trace_virtio_gpu_cmd_set_scanout(ss.scanout_id, ss.resource_id,
                                      ss.r.width, ss.r.height, ss.r.x, ss.r.y);
 
+    if (ss.scanout_id >= VIRTIO_GPU_MAX_SCANOUT ||
+        ss.scanout_id >= g->conf.max_outputs) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal scanout id specified %d",
+                      __func__, ss.scanout_id);
+        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_SCANOUT_ID;
+        return;
+    }
+
     g->enable = 1;
     if (ss.resource_id == 0) {
         scanout = &g->scanout[ss.scanout_id];
@@ -521,8 +529,7 @@ static void virtio_gpu_set_scanout(VirtIOGPU *g,
                 res->scanout_bitmask &= ~(1 << ss.scanout_id);
             }
         }
-        if (ss.scanout_id == 0 ||
-            ss.scanout_id >= g->conf.max_outputs) {
+        if (ss.scanout_id == 0) {
             qemu_log_mask(LOG_GUEST_ERROR,
                           "%s: illegal scanout id specified %d",
                           __func__, ss.scanout_id);
@@ -537,14 +544,6 @@ static void virtio_gpu_set_scanout(VirtIOGPU *g,
     }
 
     /* create a surface for this scanout */
-    if (ss.scanout_id >= VIRTIO_GPU_MAX_SCANOUT ||
-        ss.scanout_id >= g->conf.max_outputs) {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal scanout id specified %d",
-                      __func__, ss.scanout_id);
-        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_SCANOUT_ID;
-        return;
-    }
-
     res = virtio_gpu_find_resource(g, ss.resource_id);
     if (!res) {
         qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",

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File 0133-virtio-gpu-check-early-scanout-id.patch of Package qemu.5749

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