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// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#![no_main]
use std::io::{Cursor, Read, Seek, SeekFrom};
use std::mem::size_of;
use std::sync::atomic::AtomicUsize;
use std::sync::Arc;
use base::Event;
use cros_fuzz::fuzz_target;
use devices::virtio::{base_features, Block, Interrupt, Queue, VirtioDevice};
use devices::ProtectionType;
use tempfile;
use vm_memory::{GuestAddress, GuestMemory};
const MEM_SIZE: u64 = 256 * 1024 * 1024;
const DESC_SIZE: u64 = 16; // Bytes in one virtio descriptor.
const QUEUE_SIZE: u16 = 16; // Max entries in the queue.
const CMD_SIZE: usize = 16; // Bytes in the command.
fuzz_target!(|bytes| {
let size_u64 = size_of::<u64>();
let mem = GuestMemory::new(&[(GuestAddress(0), MEM_SIZE)]).unwrap();
// The fuzz data is interpreted as:
// starting index 8 bytes
// command location 8 bytes
// command 16 bytes
// descriptors circular buffer 16 bytes * 3
if bytes.len() < 4 * size_u64 {
// Need an index to start.
return;
}
let mut data_image = Cursor::new(bytes);
let first_index = read_u64(&mut data_image);
if first_index > MEM_SIZE / DESC_SIZE {
return;
}
let first_offset = first_index * DESC_SIZE;
if first_offset as usize + size_u64 > bytes.len() {
return;
}
let command_addr = read_u64(&mut data_image);
if command_addr > MEM_SIZE - CMD_SIZE as u64 {
return;
}
if mem
.write_all_at_addr(
&bytes[2 * size_u64..(2 * size_u64) + CMD_SIZE],
GuestAddress(command_addr as u64),
)
.is_err()
{
return;
}
data_image.seek(SeekFrom::Start(first_offset)).unwrap();
let desc_table = read_u64(&mut data_image);
if mem
.write_all_at_addr(&bytes[32..], GuestAddress(desc_table as u64))
.is_err()
{
return;
}
let mut q = Queue::new(QUEUE_SIZE);
q.ready = true;
q.size = QUEUE_SIZE / 2;
q.max_size = QUEUE_SIZE;
let queue_evts: Vec<Event> = vec![Event::new().unwrap()];
let queue_evt = queue_evts[0].try_clone().unwrap();
let features = base_features(ProtectionType::Unprotected);
let disk_file = tempfile::tempfile().unwrap();
let mut block =
Block::new(features, Box::new(disk_file), false, true, 512, None, None).unwrap();
block.activate(
mem,
Interrupt::new(
Arc::new(AtomicUsize::new(0)),
Event::new().unwrap(),
Event::new().unwrap(),
None, // msix_config
0xFFFF, // VIRTIO_MSI_NO_VECTOR
),
vec![q],
queue_evts,
);
queue_evt.write(77).unwrap(); // Rings the doorbell, any byte will do.
});
fn read_u64<T: Read>(readable: &mut T) -> u64 {
let mut buf = [0u8; size_of::<u64>()];
readable.read_exact(&mut buf[..]).unwrap();
u64::from_le_bytes(buf)
}