cloud-hypervisor/fuzz/fuzz_targets/block.rs
Bo Chen dda1df0a58 fuzz: Fix the building errors with recent changes
This patch adds two required dependencies to fuzz/Cargo.toml, and fixes
the building error on the 'block' fuzzer.

Signed-off-by: Bo Chen <chen.bo@intel.com>
2020-10-01 11:16:35 +01:00

139 lines
3.7 KiB
Rust

// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#![no_main]
use libfuzzer_sys::fuzz_target;
use std::ffi;
use std::fs::File;
use std::io::{self, Cursor, Read, Seek, SeekFrom};
use std::mem::size_of;
use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
use std::path::PathBuf;
use std::sync::Arc;
use virtio_devices::{Block, VirtioDevice, VirtioInterrupt, VirtioInterruptType};
use vm_memory::{Bytes, GuestAddress, GuestMemoryAtomic, GuestMemoryMmap};
use vm_virtio::Queue;
use vmm_sys_util::eventfd::EventFd;
use seccomp::SeccompAction;
const MEM_SIZE: u64 = 256 * 1024 * 1024;
const DESC_SIZE: u64 = 16; // Bytes in one virtio descriptor.
const QUEUE_SIZE: u16 = 16; // Max entries in the queue.
const CMD_SIZE: usize = 16; // Bytes in the command.
fuzz_target!(|bytes| {
let size_u64 = size_of::<u64>();
let mem = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), MEM_SIZE as usize)]).unwrap();
// The fuzz data is interpreted as:
// starting index 8 bytes
// command location 8 bytes
// command 16 bytes
// descriptors circular buffer 16 bytes * 3
if bytes.len() < 4 * size_u64 {
// Need an index to start.
return;
}
let mut data_image = Cursor::new(bytes);
let first_index = read_u64(&mut data_image);
if first_index > MEM_SIZE / DESC_SIZE {
return;
}
let first_offset = first_index * DESC_SIZE;
if first_offset as usize + size_u64 > bytes.len() {
return;
}
let command_addr = read_u64(&mut data_image);
if command_addr > MEM_SIZE - CMD_SIZE as u64 {
return;
}
if mem
.write_slice(
&bytes[2 * size_u64..(2 * size_u64) + CMD_SIZE],
GuestAddress(command_addr as u64),
)
.is_err()
{
return;
}
data_image.seek(SeekFrom::Start(first_offset)).unwrap();
let desc_table = read_u64(&mut data_image);
if mem
.write_slice(&bytes[32..], GuestAddress(desc_table as u64))
.is_err()
{
return;
}
let mut q = Queue::new(QUEUE_SIZE);
q.ready = true;
q.size = QUEUE_SIZE / 2;
q.max_size = QUEUE_SIZE;
let queue_evts: Vec<EventFd> = vec![EventFd::new(0).unwrap()];
let queue_fd = queue_evts[0].as_raw_fd();
let queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(queue_fd)) };
let shm = memfd_create(&ffi::CString::new("fuzz").unwrap(), 0).unwrap();
let disk_file: File = unsafe { File::from_raw_fd(shm) };
let raw_img = qcow::RawFile::new(disk_file, false);
let mut block = Block::new(
"tmp".to_owned(),
raw_img,
PathBuf::from(""),
false,
false,
2,
256,
SeccompAction::Allow,
)
.unwrap();
block
.activate(
GuestMemoryAtomic::new(mem),
Arc::new(NoopVirtioInterrupt {}),
vec![q],
queue_evts,
)
.ok();
queue_evt.write(77).unwrap(); // Rings the doorbell, any byte will do.
});
fn read_u64<T: Read>(readable: &mut T) -> u64 {
let mut buf = [0u8; size_of::<u64>()];
readable.read_exact(&mut buf[..]).unwrap();
u64::from_le_bytes(buf)
}
fn memfd_create(name: &ffi::CStr, flags: u32) -> Result<RawFd, io::Error> {
let res = unsafe { libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags) };
if res < 0 {
Err(io::Error::last_os_error())
} else {
Ok(res as RawFd)
}
}
pub struct NoopVirtioInterrupt {}
impl VirtioInterrupt for NoopVirtioInterrupt {
fn trigger(
&self,
_int_type: &VirtioInterruptType,
_queue: Option<&Queue>,
) -> std::result::Result<(), std::io::Error> {
Ok(())
}
}