1 // Copyright 2018 The Chromium OS Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #![no_main]
6
7 use std::io::{Cursor, Read, Seek, SeekFrom};
8 use std::mem::size_of;
9 use std::sync::atomic::AtomicUsize;
10 use std::sync::Arc;
11
12 use base::Event;
13 use cros_fuzz::fuzz_target;
14 use devices::virtio::{base_features, Block, Interrupt, Queue, VirtioDevice};
15 use devices::ProtectionType;
16 use tempfile;
17 use vm_memory::{GuestAddress, GuestMemory};
18
19 const MEM_SIZE: u64 = 256 * 1024 * 1024;
20 const DESC_SIZE: u64 = 16; // Bytes in one virtio descriptor.
21 const QUEUE_SIZE: u16 = 16; // Max entries in the queue.
22 const CMD_SIZE: usize = 16; // Bytes in the command.
23
24 fuzz_target!(|bytes| {
25 let size_u64 = size_of::<u64>();
26 let mem = GuestMemory::new(&[(GuestAddress(0), MEM_SIZE)]).unwrap();
27
28 // The fuzz data is interpreted as:
29 // starting index 8 bytes
30 // command location 8 bytes
31 // command 16 bytes
32 // descriptors circular buffer 16 bytes * 3
33 if bytes.len() < 4 * size_u64 {
34 // Need an index to start.
35 return;
36 }
37
38 let mut data_image = Cursor::new(bytes);
39
40 let first_index = read_u64(&mut data_image);
41 if first_index > MEM_SIZE / DESC_SIZE {
42 return;
43 }
44 let first_offset = first_index * DESC_SIZE;
45 if first_offset as usize + size_u64 > bytes.len() {
46 return;
47 }
48
49 let command_addr = read_u64(&mut data_image);
50 if command_addr > MEM_SIZE - CMD_SIZE as u64 {
51 return;
52 }
53 if mem
54 .write_all_at_addr(
55 &bytes[2 * size_u64..(2 * size_u64) + CMD_SIZE],
56 GuestAddress(command_addr as u64),
57 )
58 .is_err()
59 {
60 return;
61 }
62
63 data_image.seek(SeekFrom::Start(first_offset)).unwrap();
64 let desc_table = read_u64(&mut data_image);
65
66 if mem
67 .write_all_at_addr(&bytes[32..], GuestAddress(desc_table as u64))
68 .is_err()
69 {
70 return;
71 }
72
73 let mut q = Queue::new(QUEUE_SIZE);
74 q.ready = true;
75 q.size = QUEUE_SIZE / 2;
76 q.max_size = QUEUE_SIZE;
77
78 let queue_evts: Vec<Event> = vec![Event::new().unwrap()];
79 let queue_evt = queue_evts[0].try_clone().unwrap();
80
81 let features = base_features(ProtectionType::Unprotected);
82
83 let disk_file = tempfile::tempfile().unwrap();
84 let mut block =
85 Block::new(features, Box::new(disk_file), false, true, 512, None, None).unwrap();
86
87 block.activate(
88 mem,
89 Interrupt::new(
90 Arc::new(AtomicUsize::new(0)),
91 Event::new().unwrap(),
92 Event::new().unwrap(),
93 None, // msix_config
94 0xFFFF, // VIRTIO_MSI_NO_VECTOR
95 ),
96 vec![q],
97 queue_evts,
98 );
99
100 queue_evt.write(77).unwrap(); // Rings the doorbell, any byte will do.
101 });
102
read_u64<T: Read>(readable: &mut T) -> u64103 fn read_u64<T: Read>(readable: &mut T) -> u64 {
104 let mut buf = [0u8; size_of::<u64>()];
105 readable.read_exact(&mut buf[..]).unwrap();
106 u64::from_le_bytes(buf)
107 }
108