[Qemu-devel] [PATCH 2/4] vmsvga: add more fifo checks

[Gerd Hoffmann <kraxel@redhat.com>]

Make sure all fifo ptrs are within range.

Fixes: CVE-2016-4454
Cc: P J P <ppandit@redhat.com>
Reported-by: 李强 <liqiang6-s@360.cn>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/vmware_vga.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hw/display/vmware_vga.c b/hw/display/vmware_vga.c
index 63a7c05..a26e62e 100644
--- a/hw/display/vmware_vga.c
+++ b/hw/display/vmware_vga.c
@@ -563,7 +563,10 @@ static inline int vmsvga_fifo_length(struct vmsvga_state_s *s)
     if (CMD(min) < (uint8_t *) s->cmd->fifo - (uint8_t *) s->fifo) {
         return 0;
     }
-    if (CMD(max) > SVGA_FIFO_SIZE) {
+    if (CMD(max) > SVGA_FIFO_SIZE ||
+        CMD(min) >= SVGA_FIFO_SIZE ||
+        CMD(stop) >= SVGA_FIFO_SIZE ||
+        CMD(next_cmd) >= SVGA_FIFO_SIZE) {
         return 0;
     }
     if (CMD(max) < CMD(min) + 10 * 1024) {
-- 
1.8.3.1