mirror of
https://github.com/cloud-hypervisor/cloud-hypervisor.git
synced 2024-08-23 08:21:15 +00:00
The fuzzer is focusing on the virtio-pmem code that processes guest inputs (e.g. virt queues). Given 'flush' is the only virtio-pmem request, the fuzzer is essentially testing the code for parsing and error handling. Signed-off-by: Bo Chen <chen.bo@intel.com>
151 lines
4.9 KiB
Rust
151 lines
4.9 KiB
Rust
// Copyright © 2022 Intel Corporation
|
|
//
|
|
// SPDX-License-Identifier: Apache-2.0
|
|
|
|
#![no_main]
|
|
|
|
use libc::{MAP_NORESERVE, MAP_PRIVATE, PROT_READ, PROT_WRITE};
|
|
use libfuzzer_sys::fuzz_target;
|
|
use seccompiler::SeccompAction;
|
|
use std::ffi;
|
|
use std::fs::File;
|
|
use std::io;
|
|
use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
|
|
use std::sync::Arc;
|
|
use virtio_devices::{Pmem, UserspaceMapping, VirtioDevice, VirtioInterrupt, VirtioInterruptType};
|
|
use virtio_queue::{Queue, QueueT};
|
|
use vm_memory::guest_memory::FileOffset;
|
|
use vm_memory::{bitmap::AtomicBitmap, Bytes, GuestAddress, GuestMemoryAtomic, MmapRegion};
|
|
use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK};
|
|
|
|
type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>;
|
|
|
|
const QUEUE_DATA_SIZE: usize = 4;
|
|
const MEM_SIZE: usize = 256 * 1024 * 1024;
|
|
const PMEM_FILE_SIZE: usize = 128 * 1024 * 1024;
|
|
// Max entries in the queue.
|
|
const QUEUE_SIZE: u16 = 256;
|
|
// Guest physical address for descriptor table.
|
|
const DESC_TABLE_ADDR: u64 = 0;
|
|
const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64;
|
|
// Guest physical address for available ring
|
|
const AVAIL_RING_ADDR: u64 = DESC_TABLE_ADDR + DESC_TABLE_SIZE;
|
|
const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64;
|
|
// Guest physical address for used ring (requires to 4-bytes aligned)
|
|
const USED_RING_ADDR: u64 = (AVAIL_RING_ADDR + AVAIL_RING_SIZE + 3) & !3_u64;
|
|
|
|
fuzz_target!(|bytes| {
|
|
if bytes.len() < QUEUE_DATA_SIZE || bytes.len() > (QUEUE_DATA_SIZE + MEM_SIZE) {
|
|
return;
|
|
}
|
|
|
|
let mut pmem = create_dummy_pmem();
|
|
let queue_data = &bytes[..QUEUE_DATA_SIZE];
|
|
let mem_bytes = &bytes[QUEUE_DATA_SIZE..];
|
|
|
|
// Setup the virt queue with the input bytes
|
|
let q = setup_virt_queue(queue_data.try_into().unwrap());
|
|
|
|
// 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);
|
|
|
|
let evt = EventFd::new(0).unwrap();
|
|
let queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(evt.as_raw_fd())) };
|
|
|
|
// Kick the 'queue' event before activate the pmem device
|
|
queue_evt.write(1).unwrap();
|
|
|
|
pmem.activate(
|
|
guest_memory,
|
|
Arc::new(NoopVirtioInterrupt {}),
|
|
vec![(0, q, evt)],
|
|
)
|
|
.ok();
|
|
|
|
// Wait for the events to finish and pmem device worker thread to return
|
|
pmem.reset();
|
|
});
|
|
|
|
fn memfd_create_with_size(name: &ffi::CStr, flags: u32, size: usize) -> Result<RawFd, io::Error> {
|
|
let fd = unsafe { libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags) };
|
|
if fd < 0 {
|
|
return Err(io::Error::last_os_error());
|
|
}
|
|
|
|
let res = unsafe { libc::syscall(libc::SYS_ftruncate, fd, size) };
|
|
if res < 0 {
|
|
return Err(io::Error::last_os_error());
|
|
}
|
|
|
|
Ok(fd as RawFd)
|
|
}
|
|
|
|
pub struct NoopVirtioInterrupt {}
|
|
|
|
impl VirtioInterrupt for NoopVirtioInterrupt {
|
|
fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> {
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
// Create a dummy virtio-pmem device for fuzzing purpose only
|
|
fn create_dummy_pmem() -> Pmem {
|
|
let shm =
|
|
memfd_create_with_size(&ffi::CString::new("fuzz").unwrap(), 0, PMEM_FILE_SIZE).unwrap();
|
|
let file: File = unsafe { File::from_raw_fd(shm) };
|
|
|
|
// The fuzzer is focusing on the virtio-pmem code that processes guest inputs (e.g. virt queues),
|
|
// so dummy mappings (both mmap and user mapping) does the job and is faster (using smaller amount of memory).
|
|
let dummy_mapping_size = 1;
|
|
let cloned_file = file.try_clone().unwrap();
|
|
let dummy_mmap_region = MmapRegion::build(
|
|
Some(FileOffset::new(cloned_file, 0)),
|
|
dummy_mapping_size,
|
|
PROT_READ | PROT_WRITE,
|
|
MAP_NORESERVE | MAP_PRIVATE,
|
|
)
|
|
.unwrap();
|
|
let guest_addr = GuestAddress(0);
|
|
let dummy_user_mapping = UserspaceMapping {
|
|
host_addr: dummy_mmap_region.as_ptr() as u64,
|
|
mem_slot: 0,
|
|
addr: guest_addr,
|
|
len: dummy_mapping_size as u64,
|
|
mergeable: false,
|
|
};
|
|
|
|
Pmem::new(
|
|
"tmp".to_owned(),
|
|
file,
|
|
guest_addr,
|
|
dummy_user_mapping,
|
|
dummy_mmap_region,
|
|
false,
|
|
SeccompAction::Allow,
|
|
EventFd::new(EFD_NONBLOCK).unwrap(),
|
|
)
|
|
.unwrap()
|
|
}
|
|
|
|
fn setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue {
|
|
let mut q = Queue::new(QUEUE_SIZE).unwrap();
|
|
q.set_next_avail(bytes[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small
|
|
q.set_next_used(bytes[1] as u16);
|
|
q.set_event_idx(bytes[2] % 2 != 0);
|
|
q.set_size(bytes[3] as u16 % QUEUE_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_ready(true);
|
|
|
|
q
|
|
}
|