1 // Copyright © 2022 Intel Corporation 2 // 3 // SPDX-License-Identifier: Apache-2.0 4 5 #![no_main] 6 7 use std::os::unix::io::{AsRawFd, FromRawFd}; 8 use std::sync::Arc; 9 10 use libfuzzer_sys::{fuzz_target, Corpus}; 11 use seccompiler::SeccompAction; 12 use virtio_devices::{VirtioDevice, VirtioInterrupt, VirtioInterruptType}; 13 use virtio_queue::{Queue, QueueT}; 14 use vm_memory::bitmap::AtomicBitmap; 15 use vm_memory::{Bytes, GuestAddress, GuestMemoryAtomic}; 16 use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK}; 17 18 type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>; 19 20 macro_rules! align { 21 ($n:expr, $align:expr) => {{ 22 $n.div_ceil($align) * $align 23 }}; 24 } 25 26 const QUEUE_DATA_SIZE: usize = 4; 27 const MEM_SIZE: usize = 32 * 1024 * 1024; 28 // Reuse what's being done from DeviceManager::get_msi_iova_space() 29 const IOVA_SPACE_SIZE: usize = (0xfeef_ffff - 0xfee0_0000) + 1; 30 31 // Max entries in the queue. 32 const QUEUE_SIZE: u16 = 256; 33 // Descriptor table alignment 34 const DESC_TABLE_ALIGN_SIZE: u64 = 16; 35 // Available ring alignment 36 const AVAIL_RING_ALIGN_SIZE: u64 = 2; 37 // Used ring alignment 38 const USED_RING_ALIGN_SIZE: u64 = 4; 39 // Descriptor table size 40 const DESC_TABLE_SIZE: u64 = 16_u64 * QUEUE_SIZE as u64; 41 // Available ring size 42 const AVAIL_RING_SIZE: u64 = 6_u64 + 2 * QUEUE_SIZE as u64; 43 // Used ring size 44 const USED_RING_SIZE: u64 = 6_u64 + 8 * QUEUE_SIZE as u64; 45 46 // Guest memory gap 47 const GUEST_MEM_GAP: u64 = 1 * 1024 * 1024; 48 // Guest physical address for descriptor table. 49 const DESC_TABLE_ADDR: u64 = align!(MEM_SIZE as u64 + GUEST_MEM_GAP, DESC_TABLE_ALIGN_SIZE); 50 // Guest physical address for available ring 51 const AVAIL_RING_ADDR: u64 = align!(DESC_TABLE_ADDR + DESC_TABLE_SIZE, AVAIL_RING_ALIGN_SIZE); 52 // Guest physical address for used ring 53 const USED_RING_ADDR: u64 = align!(AVAIL_RING_ADDR + AVAIL_RING_SIZE, USED_RING_ALIGN_SIZE); 54 // Virtio-queue size in bytes 55 const QUEUE_BYTES_SIZE: usize = (USED_RING_ADDR + USED_RING_SIZE - DESC_TABLE_ADDR) as usize; 56 57 fuzz_target!(|bytes: &[u8]| -> Corpus { 58 if bytes.len() < (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE) 59 || bytes.len() > (QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE + MEM_SIZE) 60 { 61 return Corpus::Reject; 62 } 63 64 let (mut iommu, _) = virtio_devices::Iommu::new( 65 "fuzzer_iommu".to_owned(), 66 SeccompAction::Allow, 67 EventFd::new(EFD_NONBLOCK).unwrap(), 68 ((MEM_SIZE - IOVA_SPACE_SIZE) as u64, (MEM_SIZE - 1) as u64), 69 64, 70 None, 71 ) 72 .unwrap(); 73 74 let queue_data = &bytes[..QUEUE_DATA_SIZE]; 75 let queue_bytes = &bytes[QUEUE_DATA_SIZE..QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE]; 76 let mem_bytes = &bytes[QUEUE_DATA_SIZE + QUEUE_BYTES_SIZE..]; 77 78 // Setup the request queue with the input bytes 79 let request_queue = setup_virt_queue(queue_data.try_into().unwrap()); 80 // Given the "event queue" events are not handled from the current 81 // implementation of virtio-iommu, we simply setup the 'event_queue' 82 // with exactly the same content as the 'request_queue'. 83 let _event_queue = setup_virt_queue(queue_data.try_into().unwrap()); 84 85 // Setup the guest memory with the input bytes 86 let mem = GuestMemoryMmap::from_ranges(&[ 87 (GuestAddress(0), MEM_SIZE), 88 (GuestAddress(DESC_TABLE_ADDR), QUEUE_BYTES_SIZE), 89 ]) 90 .unwrap(); 91 if mem 92 .write_slice(queue_bytes, GuestAddress(DESC_TABLE_ADDR)) 93 .is_err() 94 { 95 return Corpus::Reject; 96 } 97 if mem.write_slice(mem_bytes, GuestAddress(0 as u64)).is_err() { 98 return Corpus::Reject; 99 } 100 let guest_memory = GuestMemoryAtomic::new(mem); 101 102 let request_evt = EventFd::new(0).unwrap(); 103 let request_queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(request_evt.as_raw_fd())) }; 104 let _event_evt = EventFd::new(0).unwrap(); 105 106 // Kick the 'queue' event before activate the vIOMMU device 107 request_queue_evt.write(1).unwrap(); 108 109 iommu 110 .activate( 111 guest_memory, 112 Arc::new(NoopVirtioInterrupt {}), 113 vec![ 114 (0, request_queue, request_evt), 115 (0, _event_queue, _event_evt), 116 ], 117 ) 118 .ok(); 119 120 // Wait for the events to finish and vIOMMU device worker thread to return 121 iommu.wait_for_epoll_threads(); 122 123 Corpus::Keep 124 }); 125 126 pub struct NoopVirtioInterrupt {} 127 128 impl VirtioInterrupt for NoopVirtioInterrupt { 129 fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> { 130 Ok(()) 131 } 132 } 133 134 fn setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue { 135 let mut q = Queue::new(QUEUE_SIZE).unwrap(); 136 q.set_next_avail(bytes[0] as u16); // 'u8' is enough given the 'QUEUE_SIZE' is small 137 q.set_next_used(bytes[1] as u16); 138 q.set_event_idx(bytes[2] % 2 != 0); 139 q.set_size(bytes[3] as u16 % QUEUE_SIZE); 140 141 q.try_set_desc_table_address(GuestAddress(DESC_TABLE_ADDR)) 142 .unwrap(); 143 q.try_set_avail_ring_address(GuestAddress(AVAIL_RING_ADDR)) 144 .unwrap(); 145 q.try_set_used_ring_address(GuestAddress(USED_RING_ADDR)) 146 .unwrap(); 147 q.set_ready(true); 148 149 q 150 } 151