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// Copyright 2015 Keegan McAllister. // Copyright 2016 Corey Farwell. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // See `LICENSE` in this repository. use std::io::{self, Read}; use std::{panic, process}; /// Utility that reads a `Vec` of bytes from standard input (stdin) /// and passes it to `closure`. All panics that occur within /// `closure` will be treated as aborts. This is done so that /// AFL considers a panic to be a crash. /// /// # Examples /// /// ```no_run /// extern crate afl; /// # struct Image; /// # impl Image { /// # fn parse(_: &[u8]) {} /// # } /// /// fn main() { /// afl::read_stdio_bytes(|read| { /// Image::parse(&read) /// }) /// } /// ``` #[deprecated(since = "0.3.3", note="This function does not use the `persistent mode` and `defered forkserver mode` and is therefore very slow. Please use fuzz() or fuzz!() instead.")] pub fn read_stdio_bytes<F>(closure: F) where F: Fn(Vec<u8>) + panic::RefUnwindSafe, { let mut input = vec![]; let result = io::stdin().read_to_end(&mut input); if result.is_err() { return; } let was_panic = panic::catch_unwind(|| { closure(input); }); if was_panic.is_err() { process::abort(); } } /// Utility that reads a `String` from standard input (stdin) and /// passes it to `closure`. If a `String` cannot be constructed from /// the data provided by standard input, `closure` will _not_ be /// called. All panics that occur within `closure` will be treated as /// aborts. This is done so that AFL considers a panic to be a crash. /// /// # Examples /// /// ```no_run /// extern crate afl; /// # struct Url; /// # impl Url { /// # fn parse(_: &str) {} /// # } /// /// fn main() { /// afl::read_stdio_string(|string| { /// Url::parse(&string) /// }) /// } /// ``` #[deprecated(since = "0.3.3", note="This function does not use the `persistent mode` and `defered forkserver mode` and is therefore very slow. Please use fuzz() or fuzz!() instead.")] pub fn read_stdio_string<F>(closure: F) where F: Fn(String) + panic::RefUnwindSafe, { let mut input = String::new(); let result = io::stdin().read_to_string(&mut input); if result.is_err() { return; } let was_panic = panic::catch_unwind(|| { closure(input); }); if was_panic.is_err() { process::abort(); } } // those functions are provided by the afl-llvm-rt static library extern "C" { fn __afl_persistent_loop(counter: usize) -> isize; fn __afl_manual_init(); } /// Fuzz a closure by passing it a `&[u8]` /// /// This slice contains a "random" quantity of "random" data. /// /// ```rust,no_run /// # extern crate afl; /// # use afl::fuzz; /// # fn main() { /// fuzz(|data|{ /// if data.len() != 6 {return} /// if data[0] != b'q' {return} /// if data[1] != b'w' {return} /// if data[2] != b'e' {return} /// if data[3] != b'r' {return} /// if data[4] != b't' {return} /// if data[5] != b'y' {return} /// panic!("BOOM") /// }); /// # } /// ``` pub fn fuzz<F>(closure: F) where F: Fn(&[u8]) + std::panic::RefUnwindSafe { // this marker strings needs to be in the produced executable for // afl-fuzz to detect `persistent mode` and `defered mode` static PERSIST_MARKER: &'static str = "##SIG_AFL_PERSISTENT##\0"; static DEFERED_MARKER: &'static str = "##SIG_AFL_DEFER_FORKSRV##\0"; // we now need a fake instruction to prevent the compiler from optimizing out // those marker strings unsafe{std::ptr::read_volatile(&PERSIST_MARKER)}; // hack used in https://github.com/bluss/bencher for black_box() unsafe{std::ptr::read_volatile(&DEFERED_MARKER)}; // unsafe { asm!("" : : "r"(&PERSIST_MARKER)) }; // hack used in nightly's back_box(), requires feature asm // unsafe { asm!("" : : "r"(&DEFERED_MARKER)) }; // sets panic hook to abort std::panic::set_hook(Box::new(|_| { std::process::abort(); })); let mut input = vec![]; // initialize forkserver there unsafe{__afl_manual_init()}; while unsafe{__afl_persistent_loop(1000)} != 0 { // get buffer from AFL through stdin let result = io::stdin().read_to_end(&mut input); if result.is_err() { return; } // We still catch unwinding panics just in case the fuzzed code modifies // the panic hook. // If so, the fuzzer will be unable to tell different bugs appart and you will // only be able to find one bug at a time before fixing it to then find a new one. let did_panic = std::panic::catch_unwind(|| { closure(&input); }).is_err(); if did_panic { // hopefully the custom panic hook will be called before and abort the // process before the stack frames are unwinded. std::process::abort(); } input.clear(); } } /// Fuzz a closure-like block of code by passing it an object of arbitrary type. /// /// You can choose the type of the argument using the syntax as in the example below. /// Please check out the `arbitrary` crate to see which types are available. /// /// For performance reasons, it is recommended that you use the native type `&[u8]` when possible. /// /// ```rust,no_run /// # #[macro_use] extern crate afl; /// # fn main() { /// fuzz!(|data: &[u8]| { /// if data.len() != 6 {return} /// if data[0] != b'q' {return} /// if data[1] != b'w' {return} /// if data[2] != b'e' {return} /// if data[3] != b'r' {return} /// if data[4] != b't' {return} /// if data[5] != b'y' {return} /// panic!("BOOM") /// }); /// # } /// ``` #[macro_export] macro_rules! fuzz { (|$buf:ident| $body:block) => { afl::fuzz(|$buf| $body); }; (|$buf:ident: &[u8]| $body:block) => { afl::fuzz(|$buf| $body); }; (|$buf:ident: $dty: ty| $body:block) => { afl::fuzz(|$buf| { let $buf: $dty = { use arbitrary::{Arbitrary, RingBuffer}; if let Ok(d) = RingBuffer::new($buf, $buf.len()).and_then(|mut b|{ Arbitrary::arbitrary(&mut b).map_err(|_| "") }) { d } else { return } }; $body }); }; } #[cfg(test)] mod test { /* use std::path::PathBuf; use std::process::{Command, Stdio}; use std::thread; use std::time; extern crate libc; extern crate tempdir; fn target_path() -> PathBuf { if PathBuf::from("../target/debug/cargo-afl-fuzz").exists() { PathBuf::from("../target/debug/") } else if PathBuf::from("target/debug/cargo-afl-fuzz").exists() { PathBuf::from("target/debug/") } else { panic!("Could not find cargo-afl-fuzz!"); } } #[test] fn test_cargo_afl_fuzz() { let temp_dir = tempdir::TempDir::new("aflrs").expect("Could not create temporary directory"); let temp_dir_path = temp_dir.path(); let mut child = Command::new(target_path().join("cargo-afl-fuzz")) .stdout(Stdio::inherit()) .stderr(Stdio::inherit()) .arg("-i") .arg(".") .arg("-o") .arg(temp_dir_path) .arg(target_path().join("examples").join("hello")) .spawn() .expect("Could not run cargo-afl-fuzz"); thread::sleep(time::Duration::from_secs(7)); child.kill().unwrap(); assert!(temp_dir_path.join("fuzzer_stats").is_file()); } */ }