1 // Copyright 2018 The ChromiumOS Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #![cfg(not(test))]
6 #![no_main]
7
8 use std::collections::BTreeMap;
9 use std::io::Cursor;
10 use std::io::Read;
11 use std::io::Seek;
12 use std::io::SeekFrom;
13 use std::mem::size_of;
14
15 use base::Event;
16 use crosvm_fuzz::fuzz_target;
17 use devices::virtio::base_features;
18 use devices::virtio::block::DiskOption;
19 use devices::virtio::BlockAsync;
20 use devices::virtio::Interrupt;
21 use devices::virtio::QueueConfig;
22 use devices::virtio::VirtioDevice;
23 use devices::IrqLevelEvent;
24 use hypervisor::ProtectionType;
25 use vm_memory::GuestAddress;
26 use vm_memory::GuestMemory;
27
28 const MEM_SIZE: u64 = 256 * 1024 * 1024;
29 const DESC_SIZE: u64 = 16; // Bytes in one virtio descriptor.
30 const QUEUE_SIZE: u16 = 16; // Max entries in the queue.
31 const CMD_SIZE: usize = 16; // Bytes in the command.
32
33 fuzz_target!(|bytes| {
34 let size_u64 = size_of::<u64>();
35 let mem = GuestMemory::new(&[(GuestAddress(0), MEM_SIZE)]).unwrap();
36
37 // The fuzz data is interpreted as:
38 // starting index 8 bytes
39 // command location 8 bytes
40 // command 16 bytes
41 // descriptors circular buffer 16 bytes * 3
42 if bytes.len() < 4 * size_u64 {
43 // Need an index to start.
44 return;
45 }
46
47 let mut data_image = Cursor::new(bytes);
48
49 let first_index = read_u64(&mut data_image);
50 if first_index > MEM_SIZE / DESC_SIZE {
51 return;
52 }
53 let first_offset = first_index * DESC_SIZE;
54 if first_offset as usize + size_u64 > bytes.len() {
55 return;
56 }
57
58 let command_addr = read_u64(&mut data_image);
59 if command_addr > MEM_SIZE - CMD_SIZE as u64 {
60 return;
61 }
62 if mem
63 .write_all_at_addr(
64 &bytes[2 * size_u64..(2 * size_u64) + CMD_SIZE],
65 GuestAddress(command_addr),
66 )
67 .is_err()
68 {
69 return;
70 }
71
72 data_image.seek(SeekFrom::Start(first_offset)).unwrap();
73 let desc_table = read_u64(&mut data_image);
74
75 if mem
76 .write_all_at_addr(&bytes[32..], GuestAddress(desc_table))
77 .is_err()
78 {
79 return;
80 }
81
82 let interrupt = Interrupt::new(
83 IrqLevelEvent::new().unwrap(),
84 None, // msix_config
85 0xFFFF, // VIRTIO_MSI_NO_VECTOR
86 #[cfg(target_arch = "x86_64")]
87 None,
88 );
89
90 let mut q = QueueConfig::new(QUEUE_SIZE, 0);
91 q.set_size(QUEUE_SIZE / 2);
92 q.set_ready(true);
93 let q = q
94 .activate(&mem, Event::new().unwrap(), interrupt.clone())
95 .expect("QueueConfig::activate");
96 let queue_evt = q.event().try_clone().unwrap();
97
98 let features = base_features(ProtectionType::Unprotected);
99
100 let disk_file = tempfile::tempfile().unwrap();
101 let disk_option = DiskOption::default();
102 let mut block = BlockAsync::new(
103 features,
104 Box::new(disk_file),
105 &disk_option,
106 None,
107 None,
108 None,
109 )
110 .unwrap();
111
112 block
113 .activate(mem, interrupt, BTreeMap::from([(0, q)]))
114 .unwrap();
115
116 queue_evt.signal().unwrap(); // Rings the doorbell
117 });
118
read_u64<T: Read>(readable: &mut T) -> u64119 fn read_u64<T: Read>(readable: &mut T) -> u64 {
120 let mut buf = [0u8; size_of::<u64>()];
121 readable.read_exact(&mut buf[..]).unwrap();
122 u64::from_le_bytes(buf)
123 }
124