File display-qxl-render-fix-race-condition-in.patch of Package qemu.30221

From: Mauro Matteo Cascella <mcascell@redhat.com>
Date: Thu, 7 Apr 2022 10:11:06 +0200
Subject: display/qxl-render: fix race condition in qxl_cursor (CVE-2021-4207)
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Git-commit: 9569f5cb5b4bffa9d3ebc8ba7da1e03830a9a895
References: bsc#1198037, CVE-2021-4207

Avoid fetching 'width' and 'height' a second time to prevent possible
race condition. Refer to security advisory
https://starlabs.sg/advisories/22-4207/ for more information.

Fixes: CVE-2021-4207
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220407081106.343235-1-mcascell@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
---
 hw/display/qxl-render.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c
index f7fdc4901e6e925054fb79af262e..e6fe37e11f8c2d62b583f2e756ca 100644
--- a/hw/display/qxl-render.c
+++ b/hw/display/qxl-render.c
@@ -260,7 +260,7 @@ static QEMUCursor *qxl_cursor(PCIQXLDevice *qxl, QXLCursor *cursor,
         }
         break;
     case SPICE_CURSOR_TYPE_ALPHA:
-        size = sizeof(uint32_t) * cursor->header.width * cursor->header.height;
+        size = sizeof(uint32_t) * c->width * c->height;
         qxl_unpack_chunks(c->data, size, qxl, &cursor->chunk, group_id);
         if (qxl->debug > 2) {
             cursor_print_ascii_art(c, "qxl/alpha");