From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41569) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VnsmX-0005CZ-G0 for qemu-devel@nongnu.org; Tue, 03 Dec 2013 11:25:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VnsmR-0006Pq-HC for qemu-devel@nongnu.org; Tue, 03 Dec 2013 11:25:05 -0500 Date: Tue, 3 Dec 2013 18:28:27 +0200 From: "Michael S. Tsirkin" Message-ID: <1386087086-3691-3-git-send-email-mst@redhat.com> References: <1386087086-3691-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1386087086-3691-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PATCH 02/23] virtio-net: out-of-bounds buffer write on load List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Anthony Liguori , Michael Roth CVE-2013-4149 QEMU 1.3.0 out-of-bounds buffer write in virtio_net_load()@hw/net/virtio-net.c > } else if (n->mac_table.in_use) { > uint8_t *buf = g_malloc0(n->mac_table.in_use); We are allocating buffer of size n->mac_table.in_use > qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN); and read to the n->mac_table.in_use size buffer n->mac_table.in_use * ETH_ALEN bytes, corrupting memory. If adversary controls state then memory written there is controlled by adversary. Reviewed-by: Michael Roth Signed-off-by: Michael S. Tsirkin --- hw/net/virtio-net.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index b75c753..2b92640 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1337,9 +1337,11 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id) qemu_get_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN); } else if (n->mac_table.in_use) { - uint8_t *buf = g_malloc0(n->mac_table.in_use); - qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN); - g_free(buf); + int i; + + for (i = 0; i < n->mac_table.in_use * ETH_ALEN; ++i) { + qemu_get_byte(f); + } n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1; n->mac_table.in_use = 0; } -- MST