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