diff --git a/devices/src/virtio/fs/fuzzing.rs b/devices/src/virtio/fs/fuzzing.rs new file mode 100644 index 0000000000..6bb4a8f89a --- /dev/null +++ b/devices/src/virtio/fs/fuzzing.rs @@ -0,0 +1,21 @@ +// Copyright 2019 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. + +use crate::virtio::fs::filesystem::FileSystem; +use crate::virtio::fs::server::Server; +use crate::virtio::{Reader, Writer}; + +// Use a file system that does nothing since we are fuzzing the server implementation. +struct NullFs; +impl FileSystem for NullFs { + type Inode = u64; + type Handle = u64; +} + +/// Fuzz the server implementation. +pub fn fuzz_server(r: Reader, w: Writer) { + let server = Server::new(NullFs); + + let _ = server.handle_message(r, w); +} diff --git a/devices/src/virtio/fs/mod.rs b/devices/src/virtio/fs/mod.rs index ff71dc125a..5e8ac413cd 100644 --- a/devices/src/virtio/fs/mod.rs +++ b/devices/src/virtio/fs/mod.rs @@ -23,6 +23,8 @@ use crate::virtio::{ mod filesystem; #[allow(dead_code)] mod fuse; +#[cfg(fuzzing)] +pub mod fuzzing; mod multikey; pub mod passthrough; mod server; diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml index 3ec2f2b86d..47d3bf25d0 100644 --- a/fuzz/Cargo.toml +++ b/fuzz/Cargo.toml @@ -23,6 +23,10 @@ members = ["."] name = "crosvm_block_fuzzer" path = "block_fuzzer.rs" +[[bin]] +name = "crosvm_fs_server_fuzzer" +path = "fs_server_fuzzer.rs" + [[bin]] name = "crosvm_qcow_fuzzer" path = "qcow_fuzzer.rs" diff --git a/fuzz/fs_server_fuzzer.rs b/fuzz/fs_server_fuzzer.rs new file mode 100644 index 0000000000..c824a0ae02 --- /dev/null +++ b/fuzz/fs_server_fuzzer.rs @@ -0,0 +1,48 @@ +// Copyright 2019 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::convert::TryInto; + +use cros_fuzz::fuzz_target; +use devices::virtio::fs::fuzzing::fuzz_server; +use devices::virtio::{create_descriptor_chain, DescriptorType, Reader, Writer}; +use sys_util::{GuestAddress, GuestMemory}; + +const MEM_SIZE: u64 = 256 * 1024 * 1024; +const BUFFER_ADDR: GuestAddress = GuestAddress(0x100); + +thread_local! { + static GUEST_MEM: GuestMemory = GuestMemory::new(&[(GuestAddress(0), MEM_SIZE)]).unwrap(); +} + +fuzz_target!(|data| { + use DescriptorType::*; + + GUEST_MEM.with(|mem| { + mem.write_all_at_addr(data, BUFFER_ADDR).unwrap(); + + let chain = create_descriptor_chain( + mem, + GuestAddress(0), + BUFFER_ADDR, + vec![ + (Readable, data.len().try_into().unwrap()), + ( + Writable, + (MEM_SIZE as u32) + .saturating_sub(data.len().try_into().unwrap()) + .saturating_sub(0x100), + ), + ], + 0, + ) + .unwrap(); + + let r = Reader::new(mem, chain.clone()).unwrap(); + let w = Writer::new(mem, chain).unwrap(); + fuzz_server(r, w); + }); +});