From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57696) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WVlKQ-0006xv-Ag for qemu-devel@nongnu.org; Thu, 03 Apr 2014 13:21:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WVlKK-00080m-4V for qemu-devel@nongnu.org; Thu, 03 Apr 2014 13:21:26 -0400 Date: Thu, 3 Apr 2014 19:50:39 +0300 From: "Michael S. Tsirkin" Message-ID: <1396543778-22307-5-git-send-email-mst@redhat.com> References: <1396543778-22307-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1396543778-22307-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PATCH v5 04/24] virtio-net: fix buffer overflow on invalid state load List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , mdroth@linux.vnet.ibm.com, qemu-stable@nongnu.org, dgilbert@redhat.com, Anthony Liguori , Laszlo Ersek , KONRAD Frederic CVE-2013-4148 QEMU 1.0 integer conversion in virtio_net_load()@hw/net/virtio-net.c Deals with loading a corrupted savevm image. > n->mac_table.in_use = qemu_get_be32(f); in_use is int so it can get negative when assigned 32bit unsigned value. > /* MAC_TABLE_ENTRIES may be different from the saved image */ > if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) { passing this check ^^^ > qemu_get_buffer(f, n->mac_table.macs, > n->mac_table.in_use * ETH_ALEN); with good in_use value, "n->mac_table.in_use * ETH_ALEN" can get positive and bigger than mac_table.macs. For example 0x81000000 satisfies this condition when ETH_ALEN is 6. Fix it by making the value unsigned. For consistency, change first_multi as well. Note: all call sites were audited to confirm that making them unsigned didn't cause any issues: it turns out we actually never do math on them, so it's easy to validate because both values are always <= MAC_TABLE_ENTRIES. Reviewed-by: Michael Roth Signed-off-by: Michael S. Tsirkin Reviewed-by: Laszlo Ersek --- include/hw/virtio/virtio-net.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h index df60f16..4b32440 100644 --- a/include/hw/virtio/virtio-net.h +++ b/include/hw/virtio/virtio-net.h @@ -176,8 +176,8 @@ typedef struct VirtIONet { uint8_t nobcast; uint8_t vhost_started; struct { - int in_use; - int first_multi; + uint32_t in_use; + uint32_t first_multi; uint8_t multi_overflow; uint8_t uni_overflow; uint8_t *macs; -- MST