[Stable-8.2.3 098/116] hw/char/virtio-serial-bus: Protect from DMA re-entrancy bugs

[Michael Tokarev]

From: Philippe Mathieu-Daudé <phi...@linaro.org>

Replace qemu_bh_new_guarded() by virtio_bh_new_guarded()
so the bus and device use the same guard. Otherwise the
DMA-reentrancy protection can be bypassed.

Fixes: CVE-2024-3446
Cc: qemu-sta...@nongnu.org
Suggested-by: Alexander Bulekov <alx...@bu.edu>
Reviewed-by: Gerd Hoffmann <kra...@redhat.com>
Acked-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Message-Id: <20240409105537.18308-4-phi...@linaro.org>
(cherry picked from commit b4295bff25f7b50de1d9cc94a9c6effd40056bca)
Signed-off-by: Michael Tokarev <m...@tls.msk.ru>

diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index dd619f0731..1221fb7f15 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -985,8 +985,7 @@ static void virtser_port_device_realize(DeviceState *dev, 
Error **errp)
         return;
     }
 
-    port->bh = qemu_bh_new_guarded(flush_queued_data_bh, port,
-                                   &dev->mem_reentrancy_guard);
+    port->bh = virtio_bh_new_guarded(dev, flush_queued_data_bh, port);
     port->elem = NULL;
 }
 
-- 
2.39.2