1 // Copyright © 2022 Intel Corporation 2 // 3 // SPDX-License-Identifier: Apache-2.0 4 5 #![no_main] 6 7 use libfuzzer_sys::fuzz_target; 8 use seccompiler::SeccompAction; 9 use std::os::unix::io::{AsRawFd, FromRawFd}; 10 use std::sync::Arc; 11 use virtio_devices::{VirtioDevice, VirtioInterrupt, VirtioInterruptType}; 12 use virtio_queue::{Queue, QueueT}; 13 use vm_memory::{bitmap::AtomicBitmap, Bytes, GuestAddress, GuestMemoryAtomic}; 14 use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK}; 15 16 type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>; 17 18 macro_rules! align { 19 ($n:expr, $align:expr) => {{ 20 (($n + $align - 1) / $align) * $align 21 }}; 22 } 23 24 const QUEUE_DATA_SIZE: usize = 4; 25 const MEM_SIZE: usize = 32 * 1024 * 1024; 26 // Reuse what's being done from DeviceManager::get_msi_iova_space() 27 const IOVA_SPACE_SIZE: usize = (0xfeef_ffff - 0xfee0_0000) + 1; 28 29 // Max entries in the queue. 30 const QUEUE_SIZE: u16 = 256; 31 // Descriptor table alignment 32 const DESC_TABLE_ALIGN_SIZE: u64 = 16; 33 // Available ring alignment 34 const AVAIL_RING_ALIGN_SIZE: u64 = 2; 35 // Used ring alignment 36 const USED_RING_ALIGN_SIZE: u64 = 4; 37 // Descriptor table size 38 const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64; 39 // Available ring size 40 const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64; 41 // Used ring size 42 const USED_RING_SIZE: u64 = 6_u64 + 8 * QUEUE_SIZE as u64; 43 44 // Guest memory gap 45 const GUEST_MEM_GAP: u64 = 1 * 1024 * 1024; 46 // Guest physical address for descriptor table. 47 const DESC_TABLE_ADDR: u64 = align!(MEM_SIZE as u64 + GUEST_MEM_GAP, DESC_TABLE_ALIGN_SIZE); 48 // Guest physical address for available ring 49 const AVAIL_RING_ADDR: u64 = align!(DESC_TABLE_ADDR + DESC_TABLE_SIZE, AVAIL_RING_ALIGN_SIZE); 50 // Guest physical address for used ring 51 const USED_RING_ADDR: u64 = align!(AVAIL_RING_ADDR + AVAIL_RING_SIZE, USED_RING_ALIGN_SIZE); 52 // Virtio-queue size in bytes 53 const QUEUE_BYTES_SIZE: usize = (USED_RING_ADDR + USED_RING_SIZE - DESC_TABLE_ADDR) as usize; 54 55 fuzz_target!(|bytes| { 56 if bytes.len() < (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE) 57 || bytes.len() > (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE + MEM_SIZE) 58 { 59 return; 60 } 61 62 let (mut iommu, _) = virtio_devices::Iommu::new( 63 "fuzzer_iommu".to_owned(), 64 SeccompAction::Allow, 65 EventFd::new(EFD_NONBLOCK).unwrap(), 66 ((MEM_SIZE - IOVA_SPACE_SIZE) as u64, (MEM_SIZE - 1) as u64), 67 None, 68 ) 69 .unwrap(); 70 71 let queue_data = &bytes[..QUEUE_DATA_SIZE]; 72 let queue_bytes = &bytes[QUEUE_DATA_SIZE..QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE]; 73 let mem_bytes = &bytes[QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE..]; 74 75 // Setup the request queue with the input bytes 76 let request_queue = setup_virt_queue(queue_data.try_into().unwrap()); 77 // Given the "event queue" events are not handled from the current 78 // implementation of virtio-iommu, we simply setup the 'event_queue' 79 // with exactly the same content as the 'request_queue'. 80 let _event_queue = setup_virt_queue(queue_data.try_into().unwrap()); 81 82 // Setup the guest memory with the input bytes 83 let mem = GuestMemoryMmap::from_ranges(&[ 84 (GuestAddress(0), MEM_SIZE), 85 (GuestAddress(DESC_TABLE_ADDR), QUEUE_BYTES_SIZE), 86 ]) 87 .unwrap(); 88 if mem 89 .write_slice(queue_bytes, GuestAddress(DESC_TABLE_ADDR)) 90 .is_err() 91 { 92 return; 93 } 94 if mem.write_slice(mem_bytes, GuestAddress(0 as u64)).is_err() { 95 return; 96 } 97 let guest_memory = GuestMemoryAtomic::new(mem); 98 99 let request_evt = EventFd::new(0).unwrap(); 100 let request_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(request_evt.as_raw_fd())) }; 101 let _event_evt = EventFd::new(0).unwrap(); 102 103 // Kick the 'queue' event before activate the vIOMMU device 104 request_queue_evt.write(1).unwrap(); 105 106 iommu 107 .activate( 108 guest_memory, 109 Arc::new(NoopVirtioInterrupt {}), 110 vec![ 111 (0, request_queue, request_evt), 112 (0, _event_queue, _event_evt), 113 ], 114 ) 115 .ok(); 116 117 // Wait for the events to finish and vIOMMU device worker thread to return 118 iommu.wait_for_epoll_threads(); 119 }); 120 121 pub struct NoopVirtioInterrupt {} 122 123 impl VirtioInterrupt for NoopVirtioInterrupt { 124 fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> { 125 Ok(()) 126 } 127 } 128 129 fn setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue { 130 let mut q = Queue::new(QUEUE_SIZE).unwrap(); 131 q.set_next_avail(bytes[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small 132 q.set_next_used(bytes[1] as u16); 133 q.set_event_idx(bytes[2] % 2 != 0); 134 q.set_size(bytes[3] as u16 % QUEUE_SIZE); 135 136 q.try_set_desc_table_address(GuestAddress(DESC_TABLE_ADDR)) 137 .unwrap(); 138 q.try_set_avail_ring_address(GuestAddress(AVAIL_RING_ADDR)) 139 .unwrap(); 140 q.try_set_used_ring_address(GuestAddress(USED_RING_ADDR)) 141 .unwrap(); 142 q.set_ready(true); 143 144 q 145 } 146