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 {
trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error>129 fn trigger(&self, _int_type: VirtioInterruptType) -> std::result::Result<(), std::io::Error> {
130 Ok(())
131 }
132 }
133
setup_virt_queue(bytes: &[u8; QUEUE_DATA_SIZE]) -> Queue134 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