1 // Copyright © 2022 Intel Corporation 2 // 3 // SPDX-License-Identifier: Apache-2.0 4 5 #![no_main] 6 7 use std::fs::File; 8 use std::io::Write; 9 use std::os::unix::io::{AsRawFd, FromRawFd, RawFd}; 10 use std::sync::Arc; 11 12 use libfuzzer_sys::{fuzz_target, Corpus}; 13 use seccompiler::SeccompAction; 14 use virtio_devices::{VirtioDevice, VirtioInterrupt, VirtioInterruptType}; 15 use virtio_queue::{Queue, QueueT}; 16 use vm_memory::bitmap::AtomicBitmap; 17 use vm_memory::{Bytes, GuestAddress, GuestMemoryAtomic}; 18 use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK}; 19 20 type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>; 21 22 macro_rules! align { 23 ($n:expr, $align:expr) => {{ 24 $n.div_ceil($align) * $align 25 }}; 26 } 27 28 const CONSOLE_INPUT_SIZE: usize = 128; 29 const QUEUE_DATA_SIZE: usize = 4; 30 const MEM_SIZE: usize = 32 * 1024 * 1024; 31 // Guest memory gap 32 const GUEST_MEM_GAP: u64 = 1 * 1024 * 1024; 33 // Guest physical address for the first virt queue 34 const BASE_VIRT_QUEUE_ADDR: u64 = MEM_SIZE as u64 + GUEST_MEM_GAP; 35 // Number of queues 36 const QUEUE_NUM: usize = 2; 37 // Max entries in the queue. 38 const QUEUE_SIZE: u16 = 256; 39 // Descriptor table alignment 40 const DESC_TABLE_ALIGN_SIZE: u64 = 16; 41 // Used ring alignment 42 const USED_RING_ALIGN_SIZE: u64 = 4; 43 // Descriptor table size 44 const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64; 45 // Available ring size 46 const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64; 47 // Padding size before used ring 48 const PADDING_SIZE: u64 = align!(AVAIL_RING_SIZE, USED_RING_ALIGN_SIZE) - AVAIL_RING_SIZE; 49 // Used ring size 50 const USED_RING_SIZE: u64 = 6_u64 + 8 * QUEUE_SIZE as u64; 51 // Virtio-queue size in bytes 52 const QUEUE_BYTES_SIZE: usize = align!( 53 DESC_TABLE_SIZE + AVAIL_RING_SIZE + PADDING_SIZE + USED_RING_SIZE, 54 DESC_TABLE_ALIGN_SIZE 55 ) as usize; 56 57 fuzz_target!(|bytes: &[u8]| -> Corpus { 58 if bytes.len() < (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE) * QUEUE_NUM + CONSOLE_INPUT_SIZE 59 || bytes.len() 60 > (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE) * QUEUE_NUM + CONSOLE_INPUT_SIZE + MEM_SIZE 61 { 62 return Corpus::Reject; 63 } 64 65 let (pipe_rx, mut pipe_tx) = create_pipe().unwrap(); 66 let output = unsafe { 67 File::from_raw_fd( 68 memfd_create(&std::ffi::CString::new("fuzz_console_output").unwrap()).unwrap(), 69 ) 70 }; 71 let endpoint = virtio_devices::Endpoint::FilePair(Arc::new(output), Arc::new(pipe_rx)); 72 73 let (mut console, _) = virtio_devices::Console::new( 74 "fuzzer_console".to_owned(), 75 endpoint, 76 None, // resize_pipe 77 false, // iommu 78 SeccompAction::Allow, 79 EventFd::new(EFD_NONBLOCK).unwrap(), 80 None, 81 ) 82 .unwrap(); 83 84 let console_input_bytes = &bytes[..CONSOLE_INPUT_SIZE]; 85 let queue_data = &bytes[CONSOLE_INPUT_SIZE..CONSOLE_INPUT_SIZE + QUEUE_DATA_SIZE * QUEUE_NUM]; 86 let queue_bytes = &bytes[CONSOLE_INPUT_SIZE + QUEUE_DATA_SIZE * QUEUE_NUM 87 ..CONSOLE_INPUT_SIZE + (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE) * QUEUE_NUM]; 88 let mem_bytes = &bytes[CONSOLE_INPUT_SIZE + (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE) * QUEUE_NUM..]; 89 90 // Setup the virt queues with the input bytes 91 let mut queues = setup_virt_queues( 92 &[ 93 &queue_data[..QUEUE_DATA_SIZE].try_into().unwrap(), 94 &queue_data[QUEUE_DATA_SIZE..QUEUE_DATA_SIZE * 2] 95 .try_into() 96 .unwrap(), 97 ], 98 BASE_VIRT_QUEUE_ADDR, 99 ); 100 101 // Setup the guest memory with the input bytes 102 let mem = GuestMemoryMmap::from_ranges(&[ 103 (GuestAddress(0), MEM_SIZE), 104 (GuestAddress(BASE_VIRT_QUEUE_ADDR), queue_bytes.len()), 105 ]) 106 .unwrap(); 107 if mem 108 .write_slice(queue_bytes, GuestAddress(BASE_VIRT_QUEUE_ADDR)) 109 .is_err() 110 { 111 return Corpus::Reject; 112 } 113 if mem.write_slice(mem_bytes, GuestAddress(0 as u64)).is_err() { 114 return Corpus::Reject; 115 } 116 let guest_memory = GuestMemoryAtomic::new(mem); 117 118 let input_queue = queues.remove(0); 119 let input_evt = EventFd::new(0).unwrap(); 120 let input_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(input_evt.as_raw_fd())) }; 121 let output_queue = queues.remove(0); 122 let output_evt = EventFd::new(0).unwrap(); 123 let output_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(output_evt.as_raw_fd())) }; 124 125 // Kick the 'queue' events and endpoint event before activate the console device 126 input_queue_evt.write(1).unwrap(); 127 output_queue_evt.write(1).unwrap(); 128 pipe_tx.write_all(console_input_bytes).unwrap(); // To use fuzzed data; 129 130 console 131 .activate( 132 guest_memory, 133 Arc::new(NoopVirtioInterrupt {}), 134 vec![(0, input_queue, input_evt), (1, output_queue, output_evt)], 135 ) 136 .unwrap(); 137 138 // Wait for the events to finish and console device worker thread to return 139 console.wait_for_epoll_threads(); 140 141 Corpus::Keep 142 }); 143 144 pub struct NoopVirtioInterrupt {} 145 146 impl VirtioInterrupt for NoopVirtioInterrupt { 147 fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> { 148 Ok(()) 149 } 150 } 151 152 fn setup_virt_queues(bytes: &[&[u8; QUEUE_DATA_SIZE]], base_addr: u64) -> Vec<Queue> { 153 let mut queues = Vec::new(); 154 for (i, b) in bytes.iter().enumerate() { 155 let mut q = Queue::new(QUEUE_SIZE).unwrap(); 156 157 let desc_table_addr = base_addr + (QUEUE_BYTES_SIZE * i) as u64; 158 let avail_ring_addr = desc_table_addr + DESC_TABLE_SIZE; 159 let used_ring_addr = avail_ring_addr + PADDING_SIZE + AVAIL_RING_SIZE; 160 q.try_set_desc_table_address(GuestAddress(desc_table_addr)) 161 .unwrap(); 162 q.try_set_avail_ring_address(GuestAddress(avail_ring_addr)) 163 .unwrap(); 164 q.try_set_used_ring_address(GuestAddress(used_ring_addr)) 165 .unwrap(); 166 167 q.set_next_avail(b[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small 168 q.set_next_used(b[1] as u16); 169 q.set_event_idx(b[2] % 2 != 0); 170 q.set_size(b[3] as u16 % QUEUE_SIZE); 171 172 q.set_ready(true); 173 queues.push(q); 174 } 175 176 queues 177 } 178 179 fn memfd_create(name: &std::ffi::CStr) -> Result<RawFd, std::io::Error> { 180 let res = unsafe { libc::syscall(libc::SYS_memfd_create, name.as_ptr(), 0) }; 181 182 if res < 0 { 183 Err(std::io::Error::last_os_error()) 184 } else { 185 Ok(res as RawFd) 186 } 187 } 188 189 fn create_pipe() -> Result<(File, File), std::io::Error> { 190 let mut pipe = [-1; 2]; 191 if unsafe { libc::pipe2(pipe.as_mut_ptr(), libc::O_CLOEXEC) } == -1 { 192 return Err(std::io::Error::last_os_error()); 193 } 194 let rx = unsafe { File::from_raw_fd(pipe[0]) }; 195 let tx = unsafe { File::from_raw_fd(pipe[1]) }; 196 197 Ok((rx, tx)) 198 } 199