From fe89fdebcaab696d525f2905b33d7b303111eade Mon Sep 17 00:00:00 2001
From: =?utf8?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 91345bd399..64a60f25f8 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -508,6 +508,14 @@ 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];
@@ -517,8 +525,7 @@ 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);
@@ -533,14 +540,6 @@ 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",
--
2.30.2