dense.rs - mozsearch

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// This test was found by a fuzzer input that crafted a way to provide

// an invalid serialization of ByteClasses that passed our verification.

// Specifically, the verification step in the deserialization of ByteClasses

// used an iterator that depends on part of the serialized bytes being correct.

// (Specifically, the encoding of the number of classes.)

#[test]

fn invalid_byte_classes() {

    let data = include_bytes!(

        "testdata/deserialize_dense_crash-9486fb7c8a93b12c12a62166b43d31640c0208a9",

);

    let _ = fuzz_run(data);

#[test]

fn invalid_byte_classes_min() {

    let data = include_bytes!(

        "testdata/deserialize_dense_minimized-from-9486fb7c8a93b12c12a62166b43d31640c0208a9",

);

    let _ = fuzz_run(data);

// This is the code from the fuzz target. Kind of sucks to duplicate it here,

// but this is fundamentally how we interpret the date.

fn fuzz_run(given_data: &[u8]) -> Option<()> {

    use regex_automata::dfa::Automaton;

    if given_data.len() < 2 {

        return None;

    let haystack_len = usize::from(given_data[0]);

    let haystack = given_data.get(1..1 + haystack_len)?;

    let given_dfa_bytes = given_data.get(1 + haystack_len..)?;

    // We help the fuzzer along by adding a preamble to the bytes that should

    // at least make these first parts valid. The preamble expects a very

    // specific sequence of bytes, so it makes sense to just force this.

    let label = "rust-regex-automata-dfa-dense\x00\x00\x00";

    assert_eq!(0, label.len() % 4);

    let endianness_check = 0xFEFFu32.to_ne_bytes().to_vec();

    let version_check = 2u32.to_ne_bytes().to_vec();

    let mut dfa_bytes: Vec<u8> = vec![];

    dfa_bytes.extend(label.as_bytes());

    dfa_bytes.extend(&endianness_check);

    dfa_bytes.extend(&version_check);

    dfa_bytes.extend(given_dfa_bytes);

    // This is the real test: checking that any input we give to

    // DFA::from_bytes will never result in a panic.

    let (dfa, _) =

        regex_automata::dfa::dense::DFA::from_bytes(&dfa_bytes).ok()?;

    let _ = dfa.try_search_fwd(&regex_automata::Input::new(haystack));

    Some(())