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From abd84f26e0fe0bc9952d91fbd35fb3a7253cfecf Mon Sep 17 00:00:00 2001
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From: Jon Maloy <jmaloy@rehat.com>
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Date: Wed, 13 Apr 2022 20:54:45 -0400
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Subject: [PATCH 1/2] display/qxl-render: fix race condition in qxl_cursor
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 (CVE-2021-4207)
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Jon Maloy <jmaloy@redhat.com>
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RH-MergeRequest: 152: display/qxl-render: fix race condition in qxl_cursor (CVE-2021-4207)
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RH-Commit: [1/1] f05b9a956f2e0ca522b5be127beff813d04b5588 (jmaloy/qemu-kvm)
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RH-Bugzilla: 2040738
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RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>
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RH-Acked-by: Mauro Matteo Cascella <None>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2040738
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Upstream: Merged
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CVE: CVE-2021-4207
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commit 9569f5cb5b4bffa9d3ebc8ba7da1e03830a9a895
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Author: Mauro Matteo Cascella <mcascell@redhat.com>
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Date:   Thu Apr 7 10:11:06 2022 +0200
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    display/qxl-render: fix race condition in qxl_cursor (CVE-2021-4207)
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    Avoid fetching 'width' and 'height' a second time to prevent possible
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    race condition. Refer to security advisory
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    https://starlabs.sg/advisories/22-4207/ for more information.
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    Fixes: CVE-2021-4207
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    Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
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    Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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    Message-Id: <20220407081106.343235-1-mcascell@redhat.com>
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    Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit 9569f5cb5b4bffa9d3ebc8ba7da1e03830a9a895)
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Signed-off-by: Jon Maloy <jmaloy@redhat.com>
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---
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 hw/display/qxl-render.c | 2 +-
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 1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c
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index d28849b121..237ed293ba 100644
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--- a/hw/display/qxl-render.c
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+++ b/hw/display/qxl-render.c
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@@ -266,7 +266,7 @@ static QEMUCursor *qxl_cursor(PCIQXLDevice *qxl, QXLCursor *cursor,
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         }
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         break;
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     case SPICE_CURSOR_TYPE_ALPHA:
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-        size = sizeof(uint32_t) * cursor->header.width * cursor->header.height;
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+        size = sizeof(uint32_t) * c->width * c->height;
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         qxl_unpack_chunks(c->data, size, qxl, &cursor->chunk, group_id);
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         if (qxl->debug > 2) {
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             cursor_print_ascii_art(c, "qxl/alpha");
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-- 
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2.27.0
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