crosvm/crosvm-fuzz/block_fuzzer.rs
Dennis Kempin a6e7d6f139 Enable compilation of fuzzing targets
Adds a fall-back to cros_fuzz when compiled without
fuzzing enabled that will just produce a main fn entrypoint
with the fuzzing code.
This allows the fuzzing code to be compiled, but won't produce
functional fuzzing binaries.

BUG=b:265829867
FIXES=b:244631591
TEST=crosvm CQ
cargo +nightly fuzz run --fuzz-dir crosvm-fuzz --features upstream-fuzz crosvm_block_fuzzer

Change-Id: Ib2602aab5c5373cb2a71dca0d8419640a00c6725
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/4167143
Commit-Queue: Dennis Kempin <denniskempin@google.com>
Reviewed-by: Zihan Chen <zihanchen@google.com>
2023-01-17 23:18:22 +00:00

122 lines
3 KiB
Rust

// Copyright 2018 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#![cfg(not(test))]
#![no_main]
use std::io::Cursor;
use std::io::Read;
use std::io::Seek;
use std::io::SeekFrom;
use std::mem::size_of;
use base::Event;
use cros_fuzz::fuzz_target;
use devices::virtio::base_features;
use devices::virtio::BlockAsync;
use devices::virtio::Interrupt;
use devices::virtio::Queue;
use devices::virtio::VirtioDevice;
use devices::IrqLevelEvent;
use hypervisor::ProtectionType;
use vm_memory::GuestAddress;
use vm_memory::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.set_size(QUEUE_SIZE / 2);
q.set_ready(true);
let queue_evt = Event::new().unwrap();
let features = base_features(ProtectionType::Unprotected);
let disk_file = tempfile::tempfile().unwrap();
let mut block = BlockAsync::new(
features,
Box::new(disk_file),
false,
true,
512,
None,
None,
None,
None,
None,
)
.unwrap();
block
.activate(
mem,
Interrupt::new(
IrqLevelEvent::new().unwrap(),
None, // msix_config
0xFFFF, // VIRTIO_MSI_NO_VECTOR
),
vec![(q, queue_evt.try_clone().unwrap())],
)
.unwrap();
queue_evt.signal().unwrap(); // Rings the doorbell
});
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)
}