191b8b00fSBo Chen // Copyright © 2022 Intel Corporation
291b8b00fSBo Chen //
391b8b00fSBo Chen // SPDX-License-Identifier: Apache-2.0
491b8b00fSBo Chen
591b8b00fSBo Chen #![no_main]
691b8b00fSBo Chen
791b8b00fSBo Chen use std::fs::File;
891b8b00fSBo Chen use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
991b8b00fSBo Chen use std::sync::Arc;
1061e57e1cSRuoqing He use std::{ffi, io};
11f041c940SRob Bradford
12f041c940SRob Bradford use libc::{MAP_NORESERVE, MAP_PRIVATE, PROT_READ, PROT_WRITE};
13*6fd5b0f6SWei Liu use libfuzzer_sys::{fuzz_target, Corpus};
14f041c940SRob Bradford use seccompiler::SeccompAction;
1591b8b00fSBo Chen use virtio_devices::{Pmem, UserspaceMapping, VirtioDevice, VirtioInterrupt, VirtioInterruptType};
1691b8b00fSBo Chen use virtio_queue::{Queue, QueueT};
1761e57e1cSRuoqing He use vm_memory::bitmap::AtomicBitmap;
1891b8b00fSBo Chen use vm_memory::guest_memory::FileOffset;
1961e57e1cSRuoqing He use vm_memory::{Bytes, GuestAddress, GuestMemoryAtomic, MmapRegion};
2091b8b00fSBo Chen use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK};
2191b8b00fSBo Chen
2291b8b00fSBo Chen type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>;
2391b8b00fSBo Chen
2491b8b00fSBo Chen const QUEUE_DATA_SIZE: usize = 4;
2591b8b00fSBo Chen const MEM_SIZE: usize = 256 * 1024 * 1024;
2691b8b00fSBo Chen const PMEM_FILE_SIZE: usize = 128 * 1024 * 1024;
2791b8b00fSBo Chen // Max entries in the queue.
2891b8b00fSBo Chen const QUEUE_SIZE: u16 = 256;
2991b8b00fSBo Chen // Guest physical address for descriptor table.
3091b8b00fSBo Chen const DESC_TABLE_ADDR: u64 = 0;
3191b8b00fSBo Chen const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64;
3291b8b00fSBo Chen // Guest physical address for available ring
3391b8b00fSBo Chen const AVAIL_RING_ADDR: u64 = DESC_TABLE_ADDR + DESC_TABLE_SIZE;
3491b8b00fSBo Chen const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64;
3591b8b00fSBo Chen // Guest physical address for used ring (requires to 4-bytes aligned)
3691b8b00fSBo Chen const USED_RING_ADDR: u64 = (AVAIL_RING_ADDR + AVAIL_RING_SIZE + 3) & !3_u64;
3791b8b00fSBo Chen
38*6fd5b0f6SWei Liu fuzz_target!(|bytes: &[u8]| -> Corpus {
3991b8b00fSBo Chen if bytes.len() < QUEUE_DATA_SIZE || bytes.len() > (QUEUE_DATA_SIZE + MEM_SIZE) {
40*6fd5b0f6SWei Liu return Corpus::Reject;
4191b8b00fSBo Chen }
4291b8b00fSBo Chen
4391b8b00fSBo Chen let mut pmem = create_dummy_pmem();
4491b8b00fSBo Chen let queue_data = &bytes[..QUEUE_DATA_SIZE];
4591b8b00fSBo Chen let mem_bytes = &bytes[QUEUE_DATA_SIZE..];
4691b8b00fSBo Chen
4791b8b00fSBo Chen // Setup the virt queue with the input bytes
4891b8b00fSBo Chen let q = setup_virt_queue(queue_data.try_into().unwrap());
4991b8b00fSBo Chen
5091b8b00fSBo Chen // Setup the guest memory with the input bytes
5191b8b00fSBo Chen let mem = GuestMemoryMmap::from_ranges(&[(GuestAddress(0), MEM_SIZE)]).unwrap();
5291b8b00fSBo Chen if mem.write_slice(mem_bytes, GuestAddress(0 as u64)).is_err() {
53*6fd5b0f6SWei Liu return Corpus::Reject;
5491b8b00fSBo Chen }
5591b8b00fSBo Chen let guest_memory = GuestMemoryAtomic::new(mem);
5691b8b00fSBo Chen
5791b8b00fSBo Chen let evt = EventFd::new(0).unwrap();
5891b8b00fSBo Chen let queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(evt.as_raw_fd())) };
5991b8b00fSBo Chen
6091b8b00fSBo Chen // Kick the 'queue' event before activate the pmem device
6191b8b00fSBo Chen queue_evt.write(1).unwrap();
6291b8b00fSBo Chen
6391b8b00fSBo Chen pmem.activate(
6491b8b00fSBo Chen guest_memory,
6591b8b00fSBo Chen Arc::new(NoopVirtioInterrupt {}),
6691b8b00fSBo Chen vec![(0, q, evt)],
6791b8b00fSBo Chen )
6891b8b00fSBo Chen .ok();
6991b8b00fSBo Chen
7091b8b00fSBo Chen // Wait for the events to finish and pmem device worker thread to return
71194b59f4SRob Bradford pmem.wait_for_epoll_threads();
72*6fd5b0f6SWei Liu
73*6fd5b0f6SWei Liu Corpus::Keep
7491b8b00fSBo Chen });
7591b8b00fSBo Chen
memfd_create_with_size(name: &ffi::CStr, flags: u32, size: usize) -> Result<RawFd, io::Error>7691b8b00fSBo Chen fn memfd_create_with_size(name: &ffi::CStr, flags: u32, size: usize) -> Result<RawFd, io::Error> {
7791b8b00fSBo Chen let fd = unsafe { libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags) };
7891b8b00fSBo Chen if fd < 0 {
7991b8b00fSBo Chen return Err(io::Error::last_os_error());
8091b8b00fSBo Chen }
8191b8b00fSBo Chen
8291b8b00fSBo Chen let res = unsafe { libc::syscall(libc::SYS_ftruncate, fd, size) };
8391b8b00fSBo Chen if res < 0 {
8491b8b00fSBo Chen return Err(io::Error::last_os_error());
8591b8b00fSBo Chen }
8691b8b00fSBo Chen
8791b8b00fSBo Chen Ok(fd as RawFd)
8891b8b00fSBo Chen }
8991b8b00fSBo Chen
9091b8b00fSBo Chen pub struct NoopVirtioInterrupt {}
9191b8b00fSBo Chen
9291b8b00fSBo Chen impl VirtioInterrupt for NoopVirtioInterrupt {
trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error>9391b8b00fSBo Chen fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> {
9491b8b00fSBo Chen Ok(())
9591b8b00fSBo Chen }
9691b8b00fSBo Chen }
9791b8b00fSBo Chen
9891b8b00fSBo Chen // Create a dummy virtio-pmem device for fuzzing purpose only
create_dummy_pmem() -> Pmem9991b8b00fSBo Chen fn create_dummy_pmem() -> Pmem {
10091b8b00fSBo Chen let shm =
10191b8b00fSBo Chen memfd_create_with_size(&ffi::CString::new("fuzz").unwrap(), 0, PMEM_FILE_SIZE).unwrap();
10291b8b00fSBo Chen let file: File = unsafe { File::from_raw_fd(shm) };
10391b8b00fSBo Chen
10491b8b00fSBo Chen // The fuzzer is focusing on the virtio-pmem code that processes guest inputs (e.g. virt queues),
10591b8b00fSBo Chen // so dummy mappings (both mmap and user mapping) does the job and is faster (using smaller amount of memory).
10691b8b00fSBo Chen let dummy_mapping_size = 1;
10791b8b00fSBo Chen let cloned_file = file.try_clone().unwrap();
10891b8b00fSBo Chen let dummy_mmap_region = MmapRegion::build(
10991b8b00fSBo Chen Some(FileOffset::new(cloned_file, 0)),
11091b8b00fSBo Chen dummy_mapping_size,
11191b8b00fSBo Chen PROT_READ | PROT_WRITE,
11291b8b00fSBo Chen MAP_NORESERVE | MAP_PRIVATE,
11391b8b00fSBo Chen )
11491b8b00fSBo Chen .unwrap();
11591b8b00fSBo Chen let guest_addr = GuestAddress(0);
11691b8b00fSBo Chen let dummy_user_mapping = UserspaceMapping {
11791b8b00fSBo Chen host_addr: dummy_mmap_region.as_ptr() as u64,
11891b8b00fSBo Chen mem_slot: 0,
11991b8b00fSBo Chen addr: guest_addr,
12091b8b00fSBo Chen len: dummy_mapping_size as u64,
12191b8b00fSBo Chen mergeable: false,
12291b8b00fSBo Chen };
12391b8b00fSBo Chen
12491b8b00fSBo Chen Pmem::new(
12591b8b00fSBo Chen "tmp".to_owned(),
12691b8b00fSBo Chen file,
12791b8b00fSBo Chen guest_addr,
12891b8b00fSBo Chen dummy_user_mapping,
12991b8b00fSBo Chen dummy_mmap_region,
13091b8b00fSBo Chen false,
13191b8b00fSBo Chen SeccompAction::Allow,
13291b8b00fSBo Chen EventFd::new(EFD_NONBLOCK).unwrap(),
1331f0e5eb6SSebastien Boeuf None,
13491b8b00fSBo Chen )
13591b8b00fSBo Chen .unwrap()
13691b8b00fSBo Chen }
13791b8b00fSBo Chen
setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue13891b8b00fSBo Chen fn setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue {
13991b8b00fSBo Chen let mut q = Queue::new(QUEUE_SIZE).unwrap();
14091b8b00fSBo Chen q.set_next_avail(bytes[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small
14191b8b00fSBo Chen q.set_next_used(bytes[1] as u16);
14291b8b00fSBo Chen q.set_event_idx(bytes[2] % 2 != 0);
14391b8b00fSBo Chen q.set_size(bytes[3] as u16 % QUEUE_SIZE);
14491b8b00fSBo Chen
14591b8b00fSBo Chen q.try_set_desc_table_address(GuestAddress(DESC_TABLE_ADDR))
14691b8b00fSBo Chen .unwrap();
14791b8b00fSBo Chen q.try_set_avail_ring_address(GuestAddress(AVAIL_RING_ADDR))
14891b8b00fSBo Chen .unwrap();
14991b8b00fSBo Chen q.try_set_used_ring_address(GuestAddress(USED_RING_ADDR))
15091b8b00fSBo Chen .unwrap();
15191b8b00fSBo Chen q.set_ready(true);
15291b8b00fSBo Chen
15391b8b00fSBo Chen q
15491b8b00fSBo Chen }
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