From 23f0db5c309893195025bc75402f3f9e1b4de743 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 3 Apr 2014 19:51:14 +0300 Subject: [PATCH] virtio: out-of-bounds buffer write on invalid state load CVE-2013-4151 QEMU 1.0 out-of-bounds buffer write in virtio_load@hw/virtio/virtio.c So we have this code since way back when: num = qemu_get_be32(f); for (i = 0; i < num; i++) { vdev->vq[i].vring.num = qemu_get_be32(f); array of vqs has size VIRTIO_PCI_QUEUE_MAX, so on invalid input this will write beyond end of buffer. Signed-off-by: Michael S. Tsirkin Reviewed-by: Michael Roth Signed-off-by: Juan Quintela (cherry picked from commit cc45995294b92d95319b4782750a3580cabdbc0c) --- hw/virtio/virtio.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index aeabf3a..05f05e7 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -891,7 +891,8 @@ int virtio_set_features(VirtIODevice *vdev, uint32_t val) int virtio_load(VirtIODevice *vdev, QEMUFile *f) { - int num, i, ret; + int i, ret; + uint32_t num; uint32_t features; uint32_t supported_features; BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); @@ -919,6 +920,11 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f) num = qemu_get_be32(f); + if (num > VIRTIO_PCI_QUEUE_MAX) { + error_report("Invalid number of PCI queues: 0x%x", num); + return -1; + } + for (i = 0; i < num; i++) { vdev->vq[i].vring.num = qemu_get_be32(f); if (k->has_variable_vring_alignment) {