Fix CVE-2016-2841, CVE-2016-2857, CVE-2016-2858

[pve-qemu-kvm.git] / debian / patches / 0005-virtio-rng-ask-for-more-data-if-queue-is-not-fully-d.patch

From b5f29c3cdd14243de19d974320f49fb3bdd37a6d Mon Sep 17 00:00:00 2001
From: Ladi Prosek <lprosek@redhat.com>
Date: Thu, 3 Mar 2016 10:48:34 +0100
Subject: [PATCH 5/5] virtio-rng: ask for more data if queue is not fully
 drained

This commit effectively reverts:

  commit 4621c1768ef5d12171cca2aa1473595ecb9f1c9e
  Author: Amit Shah <amit.shah@redhat.com>
  Date:   Wed Nov 21 11:21:19 2012 +0530

  virtio-rng: remove extra request for entropy

but instead of calling virtio_rng_process unconditionally, it
first checks to see if the queue is empty as a little bit of
optimization.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Message-Id: <1456998514-19271-1-git-send-email-lprosek@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio/virtio-rng.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
index 97d1541..3124461 100644
--- a/hw/virtio/virtio-rng.c
+++ b/hw/virtio/virtio-rng.c
@@ -66,6 +66,13 @@ static void chr_read(void *opaque, const void *buf, size_t size)
         trace_virtio_rng_pushed(vrng, len);
     }
     virtio_notify(vdev, vrng->vq);
+
+    if (!virtio_queue_empty(vrng->vq)) {
+        /* If we didn't drain the queue, call virtio_rng_process
+         * to take care of asking for more data as appropriate.
+         */
+        virtio_rng_process(vrng);
+    }
 }
 
 static void virtio_rng_process(VirtIORNG *vrng)
-- 
2.1.4