1 // Copyright 2018 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 // 5 // Copyright © 2022 Intel Corporation 6 // 7 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause 8 9 #![no_main] 10 11 use std::collections::BTreeMap; 12 use std::fs::File; 13 use std::os::unix::io::{AsRawFd, FromRawFd, RawFd}; 14 use std::path::PathBuf; 15 use std::sync::Arc; 16 use std::{ffi, io}; 17 18 use block::async_io::DiskFile; 19 use block::raw_sync::RawFileDiskSync; 20 use libfuzzer_sys::fuzz_target; 21 use seccompiler::SeccompAction; 22 use virtio_devices::{Block, VirtioDevice, VirtioInterrupt, VirtioInterruptType}; 23 use virtio_queue::{Queue, QueueT}; 24 use vm_memory::bitmap::AtomicBitmap; 25 use vm_memory::{Bytes, GuestAddress, GuestMemoryAtomic}; 26 use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK}; 27 28 type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>; 29 30 const QUEUE_DATA_SIZE: usize = 4; 31 const MEM_SIZE: usize = 256 * 1024 * 1024; 32 // Max entries in the queue. 33 const QUEUE_SIZE: u16 = 256; 34 // Guest physical address for descriptor table. 35 const DESC_TABLE_ADDR: u64 = 0; 36 const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64; 37 // Guest physical address for available ring 38 const AVAIL_RING_ADDR: u64 = DESC_TABLE_ADDR + DESC_TABLE_SIZE; 39 const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64; 40 // Guest physical address for used ring (requires to 4-bytes aligned) 41 const USED_RING_ADDR: u64 = (AVAIL_RING_ADDR + AVAIL_RING_SIZE + 3) & !3_u64; 42 43 fuzz_target!(|bytes| { 44 if bytes.len() < QUEUE_DATA_SIZE || bytes.len() > (QUEUE_DATA_SIZE + MEM_SIZE) { 45 return; 46 } 47 48 let queue_data = &bytes[..QUEUE_DATA_SIZE]; 49 let mem_bytes = &bytes[QUEUE_DATA_SIZE..]; 50 51 // Create a virtio-block device backed by a synchronous raw file 52 let shm = memfd_create(&ffi::CString::new("fuzz").unwrap(), 0).unwrap(); 53 let disk_file: File = unsafe { File::from_raw_fd(shm) }; 54 let qcow_disk = Box::new(RawFileDiskSync::new(disk_file)) as Box<dyn DiskFile>; 55 let queue_affinity = BTreeMap::new(); 56 let mut block = Block::new( 57 "tmp".to_owned(), 58 qcow_disk, 59 PathBuf::from(""), 60 false, 61 false, 62 2, 63 256, 64 None, 65 SeccompAction::Allow, 66 None, 67 EventFd::new(EFD_NONBLOCK).unwrap(), 68 None, 69 queue_affinity, 70 ) 71 .unwrap(); 72 73 // Setup the virt queue with the input bytes 74 let q = setup_virt_queue(queue_data.try_into().unwrap()); 75 76 // Setup the guest memory with the input bytes 77 let mem = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), MEM_SIZE)]).unwrap(); 78 if mem.write_slice(mem_bytes, GuestAddress(0 as u64)).is_err() { 79 return; 80 } 81 let guest_memory = GuestMemoryAtomic::new(mem); 82 83 let evt = EventFd::new(0).unwrap(); 84 let queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(evt.as_raw_fd())) }; 85 86 // Kick the 'queue' event before activate the block device 87 queue_evt.write(1).unwrap(); 88 89 block 90 .activate( 91 guest_memory, 92 Arc::new(NoopVirtioInterrupt {}), 93 vec![(0, q, evt)], 94 ) 95 .ok(); 96 97 // Wait for the events to finish and block device worker thread to return 98 block.wait_for_epoll_threads(); 99 }); 100 101 fn memfd_create(name: &ffi::CStr, flags: u32) -> Result<RawFd, io::Error> { 102 let res = unsafe { libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags) }; 103 104 if res < 0 { 105 Err(io::Error::last_os_error()) 106 } else { 107 Ok(res as RawFd) 108 } 109 } 110 111 pub struct NoopVirtioInterrupt {} 112 113 impl VirtioInterrupt for NoopVirtioInterrupt { 114 fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> { 115 Ok(()) 116 } 117 } 118 119 fn setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue { 120 let mut q = Queue::new(QUEUE_SIZE).unwrap(); 121 q.set_next_avail(bytes[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small 122 q.set_next_used(bytes[1] as u16); 123 q.set_event_idx(bytes[2] % 2 != 0); 124 q.set_size(bytes[3] as u16 % QUEUE_SIZE); 125 126 q.try_set_desc_table_address(GuestAddress(DESC_TABLE_ADDR)) 127 .unwrap(); 128 q.try_set_avail_ring_address(GuestAddress(AVAIL_RING_ADDR)) 129 .unwrap(); 130 q.try_set_used_ring_address(GuestAddress(USED_RING_ADDR)) 131 .unwrap(); 132 q.set_ready(true); 133 134 q 135 } 136