virtio: fix indirect descriptor buffer overflow

We were previously allowing arbitrarily-long indirect descriptors, which
could lead to a buffer overflow in qemu-kvm process.

CVE-2011-2212

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2011-06-20 13:42:27 +03:00
parent 0d2b962d16
commit c8eac1cfa1

View File

@ -449,9 +449,17 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
struct iovec *sg;
if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
if (elem->in_num >= ARRAY_SIZE(elem->in_sg)) {
error_report("Too many write descriptors in indirect table");
exit(1);
}
elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i);
sg = &elem->in_sg[elem->in_num++];
} else {
if (elem->out_num >= ARRAY_SIZE(elem->out_sg)) {
error_report("Too many read descriptors in indirect table");
exit(1);
}
elem->out_addr[elem->out_num] = vring_desc_addr(desc_pa, i);
sg = &elem->out_sg[elem->out_num++];
}