bump version to 2.7.1-501

[pve-qemu-kvm.git] / debian / patches / extra / CVE-2016-7422-virtio-add-check-for-descriptor-s-mapped-address.patch

From 1723b5e7962eb077353bab0772ca8114774b6c60 Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Mon, 19 Sep 2016 23:55:45 +0530
Subject: [PATCH 4/7] virtio: add check for descriptor's mapped address

virtio back end uses set of buffers to facilitate I/O operations.
If its size is too large, 'cpu_physical_memory_map' could return
a null address. This would result in a null dereference while
un-mapping descriptors. Add check to avoid it.

Reported-by: Qinghao Tang <luodalongde@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/virtio/virtio.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 74c085c..eabe573 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -473,6 +473,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, hwaddr *addr, struct iove
         }
 
         iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
+        if (!iov[num_sg].iov_base) {
+            error_report("virtio: bogus descriptor or out of resources");
+            exit(1);
+        }
+
         iov[num_sg].iov_len = len;
         addr[num_sg] = pa;
 
-- 
2.1.4