Merge tag 'fixes-20220408-pull-request' of git://git.kraxel.org/qemu into staging

two cursor/qxl related security fixes.

# gpg: Signature made Fri 08 Apr 2022 05:37:16 BST
# gpg:                using RSA key A0328CFFB93A17A79901FE7D4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* tag 'fixes-20220408-pull-request' of git://git.kraxel.org/qemu:
  ui/cursor: fix integer overflow in cursor_alloc (CVE-2021-4206)
  display/qxl-render: fix race condition in qxl_cursor (CVE-2021-4207)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 8 insertions, 1 deletions

diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c
index d28849b121..ca217004bf 100644
--- a/hw/display/qxl-render.c
+++ b/hw/display/qxl-render.c
@@ -247,6 +247,13 @@ static QEMUCursor *qxl_cursor(PCIQXLDevice *qxl, QXLCursor *cursor,
     size_t size;
 
     c = cursor_alloc(cursor->header.width, cursor->header.height);
+
+    if (!c) {
+        qxl_set_guest_bug(qxl, "%s: cursor %ux%u alloc error", __func__,
+                cursor->header.width, cursor->header.height);
+        goto fail;
+    }
+
     c->hot_x = cursor->header.hot_spot_x;
     c->hot_y = cursor->header.hot_spot_y;
     switch (cursor->header.type) {
@@ -266,7 +273,7 @@ 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");