cloud-hypervisor/fuzz/fuzz_targets/balloon.rs

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// Copyright © 2022 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0
#![no_main]
use libfuzzer_sys::fuzz_target;
use seccompiler::SeccompAction;
use std::os::unix::io::{AsRawFd, FromRawFd};
use std::sync::Arc;
use virtio_devices::{VirtioDevice, VirtioInterrupt, VirtioInterruptType};
use virtio_queue::{Queue, QueueT};
use vm_memory::{bitmap::AtomicBitmap, Bytes, GuestAddress, GuestMemoryAtomic};
use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK};
type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>;
const QUEUE_DATA_SIZE: usize = 4;
const MEM_SIZE: usize = 512 * 1024;
const BALLOON_SIZE: u64 = 512 * 1024;
// Number of queues
const QUEUE_NUM: usize = 3;
// Max entries in the queue.
const QUEUE_SIZE: u16 = 64;
// Descriptor table alignment
const DESC_TABLE_ALIGN_SIZE: u64 = 16;
// Avalable ring alignment
const AVAIL_RING_ALIGN_SIZE: u64 = 2;
// Used ring alignment
const USED_RING_ALIGN_SIZE: u64 = 4;
// Descriptor table size
const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64;
// Available ring size
const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64;
// Used ring size
const USED_RING_SIZE: u64 = 6_u64 + 8 * QUEUE_SIZE as u64;
fuzz_target!(|bytes| {
if bytes.len() < QUEUE_DATA_SIZE * QUEUE_NUM
|| bytes.len() > (QUEUE_DATA_SIZE * QUEUE_NUM + MEM_SIZE)
{
return;
}
let mut balloon = virtio_devices::Balloon::new(
"fuzzer_balloon".to_owned(),
BALLOON_SIZE,
true,
true,
SeccompAction::Allow,
EventFd::new(EFD_NONBLOCK).unwrap(),
None,
)
.unwrap();
let queue_data = &bytes[..QUEUE_DATA_SIZE * QUEUE_NUM];
let mem_bytes = &bytes[QUEUE_DATA_SIZE * QUEUE_NUM..];
// Setup the guest memory with the input bytes
let mem = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), MEM_SIZE)]).unwrap();
if mem.write_slice(mem_bytes, GuestAddress(0 as u64)).is_err() {
return;
}
let guest_memory = GuestMemoryAtomic::new(mem);
// Setup the virt queues with the input bytes
let mut queues = setup_virt_queues(
&[
&queue_data[..QUEUE_DATA_SIZE].try_into().unwrap(),
&queue_data[QUEUE_DATA_SIZE..QUEUE_DATA_SIZE * 2]
.try_into()
.unwrap(),
&queue_data[QUEUE_DATA_SIZE * 2..QUEUE_DATA_SIZE * 3]
.try_into()
.unwrap(),
],
0,
);
let inflate_q = queues.remove(0);
let inflate_evt = EventFd::new(0).unwrap();
let inflate_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(inflate_evt.as_raw_fd())) };
let deflate_q = queues.remove(0);
let deflate_evt = EventFd::new(0).unwrap();
let deflate_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(deflate_evt.as_raw_fd())) };
let reporting_q = queues.remove(0);
let reporting_evt = EventFd::new(0).unwrap();
let reporting_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(reporting_evt.as_raw_fd())) };
// Kick the 'queue' events before activate the balloon device
inflate_queue_evt.write(1).unwrap();
deflate_queue_evt.write(1).unwrap();
reporting_queue_evt.write(1).unwrap();
balloon
.activate(
guest_memory,
Arc::new(NoopVirtioInterrupt {}),
vec![
(0, inflate_q, inflate_evt),
(1, deflate_q, deflate_evt),
(2, reporting_q, reporting_evt),
],
)
.ok();
// Wait for the events to finish and balloon device worker thread to return
balloon.wait_for_epoll_threads();
});
pub struct NoopVirtioInterrupt {}
impl VirtioInterrupt for NoopVirtioInterrupt {
fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> {
Ok(())
}
}
macro_rules! align {
($n:expr, $align:expr) => {{
(($n + $align - 1) / $align) * $align
}};
}
fn setup_virt_queues(bytes: &[&[u8; QUEUE_DATA_SIZE]], base_addr: u64) -> Vec<Queue> {
let mut queues = Vec::new();
let mut base_addr = base_addr;
for b in bytes {
let mut q = Queue::new(QUEUE_SIZE).unwrap();
let desc_table_addr = align!(base_addr, DESC_TABLE_ALIGN_SIZE);
let avail_ring_addr = align!(desc_table_addr + DESC_TABLE_SIZE, AVAIL_RING_ALIGN_SIZE);
let used_ring_addr = align!(avail_ring_addr + AVAIL_RING_SIZE, USED_RING_ALIGN_SIZE);
q.try_set_desc_table_address(GuestAddress(desc_table_addr))
.unwrap();
q.try_set_avail_ring_address(GuestAddress(avail_ring_addr))
.unwrap();
q.try_set_used_ring_address(GuestAddress(used_ring_addr))
.unwrap();
q.set_next_avail(b[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small
q.set_next_used(b[1] as u16);
q.set_event_idx(b[2] % 2 != 0);
q.set_size(b[3] as u16 % QUEUE_SIZE);
q.set_ready(true);
queues.push(q);
base_addr = used_ring_addr + USED_RING_SIZE;
}
queues
}