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Diffstat (limited to 'src/engine/tests.rs')
| -rw-r--r-- | src/engine/tests.rs | 1430 |
1 files changed, 1430 insertions, 0 deletions
diff --git a/src/engine/tests.rs b/src/engine/tests.rs new file mode 100644 index 0000000..906bba0 --- /dev/null +++ b/src/engine/tests.rs @@ -0,0 +1,1430 @@ +// rstest_reuse template functions have unused variables +#![allow(unused_variables)] + +use rand::{ + self, + distributions::{self, Distribution as _}, + rngs, Rng as _, SeedableRng as _, +}; +use rstest::rstest; +use rstest_reuse::{apply, template}; +use std::{collections, fmt}; + +use crate::{ + alphabet::{Alphabet, STANDARD}, + encode::add_padding, + encoded_len, + engine::{general_purpose, naive, Config, DecodeEstimate, DecodePaddingMode, Engine}, + tests::{assert_encode_sanity, random_alphabet, random_config}, + DecodeError, PAD_BYTE, +}; + +// the case::foo syntax includes the "foo" in the generated test method names +#[template] +#[rstest(engine_wrapper, +case::general_purpose(GeneralPurposeWrapper {}), +case::naive(NaiveWrapper {}), +)] +fn all_engines<E: EngineWrapper>(engine_wrapper: E) {} + +#[apply(all_engines)] +fn rfc_test_vectors_std_alphabet<E: EngineWrapper>(engine_wrapper: E) { + let data = vec![ + ("", ""), + ("f", "Zg=="), + ("fo", "Zm8="), + ("foo", "Zm9v"), + ("foob", "Zm9vYg=="), + ("fooba", "Zm9vYmE="), + ("foobar", "Zm9vYmFy"), + ]; + + let engine = E::standard(); + let engine_no_padding = E::standard_unpadded(); + + for (orig, encoded) in &data { + let encoded_without_padding = encoded.trim_end_matches('='); + + // unpadded + { + let mut encode_buf = [0_u8; 8]; + let mut decode_buf = [0_u8; 6]; + + let encode_len = + engine_no_padding.internal_encode(orig.as_bytes(), &mut encode_buf[..]); + assert_eq!( + &encoded_without_padding, + &std::str::from_utf8(&encode_buf[0..encode_len]).unwrap() + ); + let decode_len = engine_no_padding + .decode_slice_unchecked(encoded_without_padding.as_bytes(), &mut decode_buf[..]) + .unwrap(); + assert_eq!(orig.len(), decode_len); + + assert_eq!( + orig, + &std::str::from_utf8(&decode_buf[0..decode_len]).unwrap() + ); + + // if there was any padding originally, the no padding engine won't decode it + if encoded.as_bytes().contains(&PAD_BYTE) { + assert_eq!( + Err(DecodeError::InvalidPadding), + engine_no_padding.decode(encoded) + ) + } + } + + // padded + { + let mut encode_buf = [0_u8; 8]; + let mut decode_buf = [0_u8; 6]; + + let encode_len = engine.internal_encode(orig.as_bytes(), &mut encode_buf[..]); + assert_eq!( + // doesn't have padding added yet + &encoded_without_padding, + &std::str::from_utf8(&encode_buf[0..encode_len]).unwrap() + ); + let pad_len = add_padding(orig.len(), &mut encode_buf[encode_len..]); + assert_eq!(encoded.as_bytes(), &encode_buf[..encode_len + pad_len]); + + let decode_len = engine + .decode_slice_unchecked(encoded.as_bytes(), &mut decode_buf[..]) + .unwrap(); + assert_eq!(orig.len(), decode_len); + + assert_eq!( + orig, + &std::str::from_utf8(&decode_buf[0..decode_len]).unwrap() + ); + + // if there was (canonical) padding, and we remove it, the standard engine won't decode + if encoded.as_bytes().contains(&PAD_BYTE) { + assert_eq!( + Err(DecodeError::InvalidPadding), + engine.decode(encoded_without_padding) + ) + } + } + } +} + +#[apply(all_engines)] +fn roundtrip_random<E: EngineWrapper>(engine_wrapper: E) { + let mut rng = seeded_rng(); + + let mut orig_data = Vec::<u8>::new(); + let mut encode_buf = Vec::<u8>::new(); + let mut decode_buf = Vec::<u8>::new(); + + let len_range = distributions::Uniform::new(1, 1_000); + + for _ in 0..10_000 { + let engine = E::random(&mut rng); + + orig_data.clear(); + encode_buf.clear(); + decode_buf.clear(); + + let (orig_len, _, encoded_len) = generate_random_encoded_data( + &engine, + &mut orig_data, + &mut encode_buf, + &mut rng, + &len_range, + ); + + // exactly the right size + decode_buf.resize(orig_len, 0); + + let dec_len = engine + .decode_slice_unchecked(&encode_buf[0..encoded_len], &mut decode_buf[..]) + .unwrap(); + + assert_eq!(orig_len, dec_len); + assert_eq!(&orig_data[..], &decode_buf[..dec_len]); + } +} + +#[apply(all_engines)] +fn encode_doesnt_write_extra_bytes<E: EngineWrapper>(engine_wrapper: E) { + let mut rng = seeded_rng(); + + let mut orig_data = Vec::<u8>::new(); + let mut encode_buf = Vec::<u8>::new(); + let mut encode_buf_backup = Vec::<u8>::new(); + + let input_len_range = distributions::Uniform::new(0, 1000); + + for _ in 0..10_000 { + let engine = E::random(&mut rng); + let padded = engine.config().encode_padding(); + + orig_data.clear(); + encode_buf.clear(); + encode_buf_backup.clear(); + + let orig_len = fill_rand(&mut orig_data, &mut rng, &input_len_range); + + let prefix_len = 1024; + // plenty of prefix and suffix + fill_rand_len(&mut encode_buf, &mut rng, prefix_len * 2 + orig_len * 2); + encode_buf_backup.extend_from_slice(&encode_buf[..]); + + let expected_encode_len_no_pad = encoded_len(orig_len, false).unwrap(); + + let encoded_len_no_pad = + engine.internal_encode(&orig_data[..], &mut encode_buf[prefix_len..]); + assert_eq!(expected_encode_len_no_pad, encoded_len_no_pad); + + // no writes past what it claimed to write + assert_eq!(&encode_buf_backup[..prefix_len], &encode_buf[..prefix_len]); + assert_eq!( + &encode_buf_backup[(prefix_len + encoded_len_no_pad)..], + &encode_buf[(prefix_len + encoded_len_no_pad)..] + ); + + let encoded_data = &encode_buf[prefix_len..(prefix_len + encoded_len_no_pad)]; + assert_encode_sanity( + std::str::from_utf8(encoded_data).unwrap(), + // engines don't pad + false, + orig_len, + ); + + // pad so we can decode it in case our random engine requires padding + let pad_len = if padded { + add_padding(orig_len, &mut encode_buf[prefix_len + encoded_len_no_pad..]) + } else { + 0 + }; + + assert_eq!( + orig_data, + engine + .decode(&encode_buf[prefix_len..(prefix_len + encoded_len_no_pad + pad_len)],) + .unwrap() + ); + } +} + +#[apply(all_engines)] +fn encode_engine_slice_fits_into_precisely_sized_slice<E: EngineWrapper>(engine_wrapper: E) { + let mut orig_data = Vec::new(); + let mut encoded_data = Vec::new(); + let mut decoded = Vec::new(); + + let input_len_range = distributions::Uniform::new(0, 1000); + + let mut rng = rngs::SmallRng::from_entropy(); + + for _ in 0..10_000 { + orig_data.clear(); + encoded_data.clear(); + decoded.clear(); + + let input_len = input_len_range.sample(&mut rng); + + for _ in 0..input_len { + orig_data.push(rng.gen()); + } + + let engine = E::random(&mut rng); + + let encoded_size = encoded_len(input_len, engine.config().encode_padding()).unwrap(); + + encoded_data.resize(encoded_size, 0); + + assert_eq!( + encoded_size, + engine.encode_slice(&orig_data, &mut encoded_data).unwrap() + ); + + assert_encode_sanity( + std::str::from_utf8(&encoded_data[0..encoded_size]).unwrap(), + engine.config().encode_padding(), + input_len, + ); + + engine + .decode_vec(&encoded_data[0..encoded_size], &mut decoded) + .unwrap(); + assert_eq!(orig_data, decoded); + } +} + +#[apply(all_engines)] +fn decode_doesnt_write_extra_bytes<E>(engine_wrapper: E) +where + E: EngineWrapper, + <<E as EngineWrapper>::Engine as Engine>::Config: fmt::Debug, +{ + let mut rng = seeded_rng(); + + let mut orig_data = Vec::<u8>::new(); + let mut encode_buf = Vec::<u8>::new(); + let mut decode_buf = Vec::<u8>::new(); + let mut decode_buf_backup = Vec::<u8>::new(); + + let len_range = distributions::Uniform::new(1, 1_000); + + for _ in 0..10_000 { + let engine = E::random(&mut rng); + + orig_data.clear(); + encode_buf.clear(); + decode_buf.clear(); + decode_buf_backup.clear(); + + let orig_len = fill_rand(&mut orig_data, &mut rng, &len_range); + encode_buf.resize(orig_len * 2 + 100, 0); + + let encoded_len = engine + .encode_slice(&orig_data[..], &mut encode_buf[..]) + .unwrap(); + encode_buf.truncate(encoded_len); + + // oversize decode buffer so we can easily tell if it writes anything more than + // just the decoded data + let prefix_len = 1024; + // plenty of prefix and suffix + fill_rand_len(&mut decode_buf, &mut rng, prefix_len * 2 + orig_len * 2); + decode_buf_backup.extend_from_slice(&decode_buf[..]); + + let dec_len = engine + .decode_slice_unchecked(&encode_buf, &mut decode_buf[prefix_len..]) + .unwrap(); + + assert_eq!(orig_len, dec_len); + assert_eq!( + &orig_data[..], + &decode_buf[prefix_len..prefix_len + dec_len] + ); + assert_eq!(&decode_buf_backup[..prefix_len], &decode_buf[..prefix_len]); + assert_eq!( + &decode_buf_backup[prefix_len + dec_len..], + &decode_buf[prefix_len + dec_len..] + ); + } +} + +#[apply(all_engines)] +fn decode_detect_invalid_last_symbol<E: EngineWrapper>(engine_wrapper: E) { + // 0xFF -> "/w==", so all letters > w, 0-9, and '+', '/' should get InvalidLastSymbol + let engine = E::standard(); + + assert_eq!(Ok(vec![0x89, 0x85]), engine.decode("iYU=")); + assert_eq!(Ok(vec![0xFF]), engine.decode("/w==")); + + for (suffix, offset) in vec![ + // suffix, offset of bad byte from start of suffix + ("/x==", 1_usize), + ("/z==", 1_usize), + ("/0==", 1_usize), + ("/9==", 1_usize), + ("/+==", 1_usize), + ("//==", 1_usize), + // trailing 01 + ("iYV=", 2_usize), + // trailing 10 + ("iYW=", 2_usize), + // trailing 11 + ("iYX=", 2_usize), + ] { + for prefix_quads in 0..256 { + let mut encoded = "AAAA".repeat(prefix_quads); + encoded.push_str(suffix); + + assert_eq!( + Err(DecodeError::InvalidLastSymbol( + encoded.len() - 4 + offset, + suffix.as_bytes()[offset], + )), + engine.decode(encoded.as_str()) + ); + } + } +} + +#[apply(all_engines)] +fn decode_detect_invalid_last_symbol_when_length_is_also_invalid<E: EngineWrapper>( + engine_wrapper: E, +) { + let mut rng = seeded_rng(); + + // check across enough lengths that it would likely cover any implementation's various internal + // small/large input division + for len in (0_usize..256).map(|len| len * 4 + 1) { + let engine = E::random_alphabet(&mut rng, &STANDARD); + + let mut input = vec![b'A'; len]; + + // with a valid last char, it's InvalidLength + assert_eq!(Err(DecodeError::InvalidLength), engine.decode(&input)); + // after mangling the last char, it's InvalidByte + input[len - 1] = b'"'; + assert_eq!( + Err(DecodeError::InvalidByte(len - 1, b'"')), + engine.decode(&input) + ); + } +} + +#[apply(all_engines)] +fn decode_detect_invalid_last_symbol_every_possible_two_symbols<E: EngineWrapper>( + engine_wrapper: E, +) { + let engine = E::standard(); + + let mut base64_to_bytes = collections::HashMap::new(); + + for b in 0_u8..=255 { + let mut b64 = vec![0_u8; 4]; + assert_eq!(2, engine.internal_encode(&[b], &mut b64[..])); + let _ = add_padding(1, &mut b64[2..]); + + assert!(base64_to_bytes.insert(b64, vec![b]).is_none()); + } + + // every possible combination of trailing symbols must either decode to 1 byte or get InvalidLastSymbol, with or without any leading chunks + + let mut prefix = Vec::new(); + for _ in 0..256 { + let mut clone = prefix.clone(); + + let mut symbols = [0_u8; 4]; + for &s1 in STANDARD.symbols.iter() { + symbols[0] = s1; + for &s2 in STANDARD.symbols.iter() { + symbols[1] = s2; + symbols[2] = PAD_BYTE; + symbols[3] = PAD_BYTE; + + // chop off previous symbols + clone.truncate(prefix.len()); + clone.extend_from_slice(&symbols[..]); + let decoded_prefix_len = prefix.len() / 4 * 3; + + match base64_to_bytes.get(&symbols[..]) { + Some(bytes) => { + let res = engine + .decode(&clone) + // remove prefix + .map(|decoded| decoded[decoded_prefix_len..].to_vec()); + + assert_eq!(Ok(bytes.clone()), res); + } + None => assert_eq!( + Err(DecodeError::InvalidLastSymbol(1, s2)), + engine.decode(&symbols[..]) + ), + } + } + } + + prefix.extend_from_slice(b"AAAA"); + } +} + +#[apply(all_engines)] +fn decode_detect_invalid_last_symbol_every_possible_three_symbols<E: EngineWrapper>( + engine_wrapper: E, +) { + let engine = E::standard(); + + let mut base64_to_bytes = collections::HashMap::new(); + + let mut bytes = [0_u8; 2]; + for b1 in 0_u8..=255 { + bytes[0] = b1; + for b2 in 0_u8..=255 { + bytes[1] = b2; + let mut b64 = vec![0_u8; 4]; + assert_eq!(3, engine.internal_encode(&bytes, &mut b64[..])); + let _ = add_padding(2, &mut b64[3..]); + + let mut v = Vec::with_capacity(2); + v.extend_from_slice(&bytes[..]); + + assert!(base64_to_bytes.insert(b64, v).is_none()); + } + } + + // every possible combination of symbols must either decode to 2 bytes or get InvalidLastSymbol, with or without any leading chunks + + let mut prefix = Vec::new(); + for _ in 0..256 { + let mut input = prefix.clone(); + + let mut symbols = [0_u8; 4]; + for &s1 in STANDARD.symbols.iter() { + symbols[0] = s1; + for &s2 in STANDARD.symbols.iter() { + symbols[1] = s2; + for &s3 in STANDARD.symbols.iter() { + symbols[2] = s3; + symbols[3] = PAD_BYTE; + + // chop off previous symbols + input.truncate(prefix.len()); + input.extend_from_slice(&symbols[..]); + let decoded_prefix_len = prefix.len() / 4 * 3; + + match base64_to_bytes.get(&symbols[..]) { + Some(bytes) => { + let res = engine + .decode(&input) + // remove prefix + .map(|decoded| decoded[decoded_prefix_len..].to_vec()); + + assert_eq!(Ok(bytes.clone()), res); + } + None => assert_eq!( + Err(DecodeError::InvalidLastSymbol(2, s3)), + engine.decode(&symbols[..]) + ), + } + } + } + } + prefix.extend_from_slice(b"AAAA"); + } +} + +#[apply(all_engines)] +fn decode_invalid_trailing_bits_ignored_when_configured<E: EngineWrapper>(engine_wrapper: E) { + let strict = E::standard(); + let forgiving = E::standard_allow_trailing_bits(); + + fn assert_tolerant_decode<E: Engine>( + engine: &E, + input: &mut String, + b64_prefix_len: usize, + expected_decode_bytes: Vec<u8>, + data: &str, + ) { + let prefixed = prefixed_data(input, b64_prefix_len, data); + let decoded = engine.decode(prefixed); + // prefix is always complete chunks + let decoded_prefix_len = b64_prefix_len / 4 * 3; + assert_eq!( + Ok(expected_decode_bytes), + decoded.map(|v| v[decoded_prefix_len..].to_vec()) + ); + } + + let mut prefix = String::new(); + for _ in 0..256 { + let mut input = prefix.clone(); + + // example from https://github.com/marshallpierce/rust-base64/issues/75 + assert!(strict + .decode(prefixed_data(&mut input, prefix.len(), "/w==")) + .is_ok()); + assert!(strict + .decode(prefixed_data(&mut input, prefix.len(), "iYU=")) + .is_ok()); + // trailing 01 + assert_tolerant_decode(&forgiving, &mut input, prefix.len(), vec![255], "/x=="); + assert_tolerant_decode(&forgiving, &mut input, prefix.len(), vec![137, 133], "iYV="); + // trailing 10 + assert_tolerant_decode(&forgiving, &mut input, prefix.len(), vec![255], "/y=="); + assert_tolerant_decode(&forgiving, &mut input, prefix.len(), vec![137, 133], "iYW="); + // trailing 11 + assert_tolerant_decode(&forgiving, &mut input, prefix.len(), vec![255], "/z=="); + assert_tolerant_decode(&forgiving, &mut input, prefix.len(), vec![137, 133], "iYX="); + + prefix.push_str("AAAA"); + } +} + +#[apply(all_engines)] +fn decode_invalid_byte_error<E: EngineWrapper>(engine_wrapper: E) { + let mut rng = seeded_rng(); + + let mut orig_data = Vec::<u8>::new(); + let mut encode_buf = Vec::<u8>::new(); + let mut decode_buf = Vec::<u8>::new(); + + let len_range = distributions::Uniform::new(1, 1_000); + + for _ in 0..10_000 { + let alphabet = random_alphabet(&mut rng); + let engine = E::random_alphabet(&mut rng, alphabet); + + orig_data.clear(); + encode_buf.clear(); + decode_buf.clear(); + + let (orig_len, encoded_len_just_data, encoded_len_with_padding) = + generate_random_encoded_data( + &engine, + &mut orig_data, + &mut encode_buf, + &mut rng, + &len_range, + ); + + // exactly the right size + decode_buf.resize(orig_len, 0); + + // replace one encoded byte with an invalid byte + let invalid_byte: u8 = loop { + let byte: u8 = rng.gen(); + + if alphabet.symbols.contains(&byte) { + continue; + } else { + break byte; + } + }; + + let invalid_range = distributions::Uniform::new(0, orig_len); + let invalid_index = invalid_range.sample(&mut rng); + encode_buf[invalid_index] = invalid_byte; + + assert_eq!( + Err(DecodeError::InvalidByte(invalid_index, invalid_byte)), + engine.decode_slice_unchecked( + &encode_buf[0..encoded_len_with_padding], + &mut decode_buf[..], + ) + ); + } +} + +/// Any amount of padding anywhere before the final non padding character = invalid byte at first +/// pad byte. +/// From this, we know padding must extend to the end of the input. +#[apply(all_engines)] +fn decode_padding_before_final_non_padding_char_error_invalid_byte<E: EngineWrapper>( + engine_wrapper: E, +) { + let mut rng = seeded_rng(); + + // the different amounts of proper padding, w/ offset from end for the last non-padding char + let suffixes = vec![("/w==", 2), ("iYu=", 1), ("zzzz", 0)]; + + let prefix_quads_range = distributions::Uniform::from(0..=256); + + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for _ in 0..100_000 { + for (suffix, offset) in suffixes.iter() { + let mut s = "ABCD".repeat(prefix_quads_range.sample(&mut rng)); + s.push_str(suffix); + let mut encoded = s.into_bytes(); + + // calculate a range to write padding into that leaves at least one non padding char + let last_non_padding_offset = encoded.len() - 1 - offset; + + // don't include last non padding char as it must stay not padding + let padding_end = rng.gen_range(0..last_non_padding_offset); + + // don't use more than 100 bytes of padding, but also use shorter lengths when + // padding_end is near the start of the encoded data to avoid biasing to padding + // the entire prefix on short lengths + let padding_len = rng.gen_range(1..=usize::min(100, padding_end + 1)); + let padding_start = padding_end.saturating_sub(padding_len); + + encoded[padding_start..=padding_end].fill(PAD_BYTE); + + assert_eq!( + Err(DecodeError::InvalidByte(padding_start, PAD_BYTE)), + engine.decode(&encoded), + ); + } + } + } +} + +/// Any amount of padding before final chunk that crosses over into final chunk with 1-4 bytes = +/// invalid byte at first pad byte (except for 1 byte suffix = invalid length). +/// From this we know the padding must start in the final chunk. +#[apply(all_engines)] +fn decode_padding_starts_before_final_chunk_error_invalid_byte<E: EngineWrapper>( + engine_wrapper: E, +) { + let mut rng = seeded_rng(); + + // must have at least one prefix quad + let prefix_quads_range = distributions::Uniform::from(1..256); + // including 1 just to make sure that it really does produce invalid length + let suffix_pad_len_range = distributions::Uniform::from(1..=4); + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + for _ in 0..100_000 { + let suffix_len = suffix_pad_len_range.sample(&mut rng); + let mut encoded = "ABCD" + .repeat(prefix_quads_range.sample(&mut rng)) + .into_bytes(); + encoded.resize(encoded.len() + suffix_len, PAD_BYTE); + + // amount of padding must be long enough to extend back from suffix into previous + // quads + let padding_len = rng.gen_range(suffix_len + 1..encoded.len()); + // no non-padding after padding in this test, so padding goes to the end + let padding_start = encoded.len() - padding_len; + encoded[padding_start..].fill(PAD_BYTE); + + if suffix_len == 1 { + assert_eq!(Err(DecodeError::InvalidLength), engine.decode(&encoded),); + } else { + assert_eq!( + Err(DecodeError::InvalidByte(padding_start, PAD_BYTE)), + engine.decode(&encoded), + ); + } + } + } +} + +/// 0-1 bytes of data before any amount of padding in final chunk = invalid byte, since padding +/// is not valid data (consistent with error for pad bytes in earlier chunks). +/// From this we know there must be 2-3 bytes of data before padding +#[apply(all_engines)] +fn decode_too_little_data_before_padding_error_invalid_byte<E: EngineWrapper>(engine_wrapper: E) { + let mut rng = seeded_rng(); + + // want to test no prefix quad case, so start at 0 + let prefix_quads_range = distributions::Uniform::from(0_usize..256); + let suffix_data_len_range = distributions::Uniform::from(0_usize..=1); + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + for _ in 0..100_000 { + let suffix_data_len = suffix_data_len_range.sample(&mut rng); + let prefix_quad_len = prefix_quads_range.sample(&mut rng); + + // ensure there is a suffix quad + let min_padding = usize::from(suffix_data_len == 0); + + // for all possible padding lengths + for padding_len in min_padding..=(4 - suffix_data_len) { + let mut encoded = "ABCD".repeat(prefix_quad_len).into_bytes(); + encoded.resize(encoded.len() + suffix_data_len, b'A'); + encoded.resize(encoded.len() + padding_len, PAD_BYTE); + + if suffix_data_len + padding_len == 1 { + assert_eq!(Err(DecodeError::InvalidLength), engine.decode(&encoded),); + } else { + assert_eq!( + Err(DecodeError::InvalidByte( + prefix_quad_len * 4 + suffix_data_len, + PAD_BYTE, + )), + engine.decode(&encoded), + "suffix data len {} pad len {}", + suffix_data_len, + padding_len + ); + } + } + } + } +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 1 +#[apply(all_engines)] +fn decode_malleability_test_case_3_byte_suffix_valid<E: EngineWrapper>(engine_wrapper: E) { + assert_eq!( + b"Hello".as_slice(), + &E::standard().decode("SGVsbG8=").unwrap() + ); +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 2 +#[apply(all_engines)] +fn decode_malleability_test_case_3_byte_suffix_invalid_trailing_symbol<E: EngineWrapper>( + engine_wrapper: E, +) { + assert_eq!( + DecodeError::InvalidLastSymbol(6, 0x39), + E::standard().decode("SGVsbG9=").unwrap_err() + ); +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 3 +#[apply(all_engines)] +fn decode_malleability_test_case_3_byte_suffix_no_padding<E: EngineWrapper>(engine_wrapper: E) { + assert_eq!( + DecodeError::InvalidPadding, + E::standard().decode("SGVsbG9").unwrap_err() + ); +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 4 +#[apply(all_engines)] +fn decode_malleability_test_case_2_byte_suffix_valid_two_padding_symbols<E: EngineWrapper>( + engine_wrapper: E, +) { + assert_eq!( + b"Hell".as_slice(), + &E::standard().decode("SGVsbA==").unwrap() + ); +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 5 +#[apply(all_engines)] +fn decode_malleability_test_case_2_byte_suffix_short_padding<E: EngineWrapper>(engine_wrapper: E) { + assert_eq!( + DecodeError::InvalidPadding, + E::standard().decode("SGVsbA=").unwrap_err() + ); +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 6 +#[apply(all_engines)] +fn decode_malleability_test_case_2_byte_suffix_no_padding<E: EngineWrapper>(engine_wrapper: E) { + assert_eq!( + DecodeError::InvalidPadding, + E::standard().decode("SGVsbA").unwrap_err() + ); +} + +// https://eprint.iacr.org/2022/361.pdf table 2, test 7 +#[apply(all_engines)] +fn decode_malleability_test_case_2_byte_suffix_too_much_padding<E: EngineWrapper>( + engine_wrapper: E, +) { + assert_eq!( + DecodeError::InvalidByte(6, PAD_BYTE), + E::standard().decode("SGVsbA====").unwrap_err() + ); +} + +/// Requires canonical padding -> accepts 2 + 2, 3 + 1, 4 + 0 final quad configurations +#[apply(all_engines)] +fn decode_pad_mode_requires_canonical_accepts_canonical<E: EngineWrapper>(engine_wrapper: E) { + assert_all_suffixes_ok( + E::standard_with_pad_mode(true, DecodePaddingMode::RequireCanonical), + vec!["/w==", "iYU=", "AAAA"], + ); +} + +/// Requires canonical padding -> rejects 2 + 0-1, 3 + 0 final chunk configurations +#[apply(all_engines)] +fn decode_pad_mode_requires_canonical_rejects_non_canonical<E: EngineWrapper>(engine_wrapper: E) { + let engine = E::standard_with_pad_mode(true, DecodePaddingMode::RequireCanonical); + + let suffixes = vec!["/w", "/w=", "iYU"]; + for num_prefix_quads in 0..256 { + for &suffix in suffixes.iter() { + let mut encoded = "AAAA".repeat(num_prefix_quads); + encoded.push_str(suffix); + + let res = engine.decode(&encoded); + + assert_eq!(Err(DecodeError::InvalidPadding), res); + } + } +} + +/// Requires no padding -> accepts 2 + 0, 3 + 0, 4 + 0 final chunk configuration +#[apply(all_engines)] +fn decode_pad_mode_requires_no_padding_accepts_no_padding<E: EngineWrapper>(engine_wrapper: E) { + assert_all_suffixes_ok( + E::standard_with_pad_mode(true, DecodePaddingMode::RequireNone), + vec!["/w", "iYU", "AAAA"], + ); +} + +/// Requires no padding -> rejects 2 + 1-2, 3 + 1 final chunk configuration +#[apply(all_engines)] +fn decode_pad_mode_requires_no_padding_rejects_any_padding<E: EngineWrapper>(engine_wrapper: E) { + let engine = E::standard_with_pad_mode(true, DecodePaddingMode::RequireNone); + + let suffixes = vec!["/w=", "/w==", "iYU="]; + for num_prefix_quads in 0..256 { + for &suffix in suffixes.iter() { + let mut encoded = "AAAA".repeat(num_prefix_quads); + encoded.push_str(suffix); + + let res = engine.decode(&encoded); + + assert_eq!(Err(DecodeError::InvalidPadding), res); + } + } +} + +/// Indifferent padding accepts 2 + 0-2, 3 + 0-1, 4 + 0 final chunk configuration +#[apply(all_engines)] +fn decode_pad_mode_indifferent_padding_accepts_anything<E: EngineWrapper>(engine_wrapper: E) { + assert_all_suffixes_ok( + E::standard_with_pad_mode(true, DecodePaddingMode::Indifferent), + vec!["/w", "/w=", "/w==", "iYU", "iYU=", "AAAA"], + ); +} + +//this is a MAY in the rfc: https://tools.ietf.org/html/rfc4648#section-3.3 +#[apply(all_engines)] +fn decode_pad_byte_in_penultimate_quad_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + // leave room for at least one pad byte in penultimate quad + for num_valid_bytes_penultimate_quad in 0..4 { + // can't have 1 or it would be invalid length + for num_pad_bytes_in_final_quad in 2..=4 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + + // varying amounts of padding in the penultimate quad + for _ in 0..num_valid_bytes_penultimate_quad { + s.push('A'); + } + // finish penultimate quad with padding + for _ in num_valid_bytes_penultimate_quad..4 { + s.push('='); + } + // and more padding in the final quad + for _ in 0..num_pad_bytes_in_final_quad { + s.push('='); + } + + // padding should be an invalid byte before the final quad. + // Could argue that the *next* padding byte (in the next quad) is technically the first + // erroneous one, but reporting that accurately is more complex and probably nobody cares + assert_eq!( + DecodeError::InvalidByte( + num_prefix_quads * 4 + num_valid_bytes_penultimate_quad, + b'=', + ), + engine.decode(&s).unwrap_err() + ); + } + } + } + } +} + +#[apply(all_engines)] +fn decode_bytes_after_padding_in_final_quad_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + // leave at least one byte in the quad for padding + for bytes_after_padding in 1..4 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + + // every invalid padding position with a 3-byte final quad: 1 to 3 bytes after padding + for _ in 0..(3 - bytes_after_padding) { + s.push('A'); + } + s.push('='); + for _ in 0..bytes_after_padding { + s.push('A'); + } + + // First (and only) padding byte is invalid. + assert_eq!( + DecodeError::InvalidByte( + num_prefix_quads * 4 + (3 - bytes_after_padding), + b'=' + ), + engine.decode(&s).unwrap_err() + ); + } + } + } +} + +#[apply(all_engines)] +fn decode_absurd_pad_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + s.push_str("==Y=Wx===pY=2U====="); + + // first padding byte + assert_eq!( + DecodeError::InvalidByte(num_prefix_quads * 4, b'='), + engine.decode(&s).unwrap_err() + ); + } + } +} + +#[apply(all_engines)] +fn decode_too_much_padding_returns_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + // add enough padding to ensure that we'll hit all decode stages at the different lengths + for pad_bytes in 1..=64 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + let padding: String = "=".repeat(pad_bytes); + s.push_str(&padding); + + if pad_bytes % 4 == 1 { + assert_eq!(DecodeError::InvalidLength, engine.decode(&s).unwrap_err()); + } else { + assert_eq!( + DecodeError::InvalidByte(num_prefix_quads * 4, b'='), + engine.decode(&s).unwrap_err() + ); + } + } + } + } +} + +#[apply(all_engines)] +fn decode_padding_followed_by_non_padding_returns_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + for pad_bytes in 0..=32 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + let padding: String = "=".repeat(pad_bytes); + s.push_str(&padding); + s.push('E'); + + if pad_bytes % 4 == 0 { + assert_eq!(DecodeError::InvalidLength, engine.decode(&s).unwrap_err()); + } else { + assert_eq!( + DecodeError::InvalidByte(num_prefix_quads * 4, b'='), + engine.decode(&s).unwrap_err() + ); + } + } + } + } +} + +#[apply(all_engines)] +fn decode_one_char_in_final_quad_with_padding_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + s.push_str("E="); + + assert_eq!( + DecodeError::InvalidByte(num_prefix_quads * 4 + 1, b'='), + engine.decode(&s).unwrap_err() + ); + + // more padding doesn't change the error + s.push('='); + assert_eq!( + DecodeError::InvalidByte(num_prefix_quads * 4 + 1, b'='), + engine.decode(&s).unwrap_err() + ); + + s.push('='); + assert_eq!( + DecodeError::InvalidByte(num_prefix_quads * 4 + 1, b'='), + engine.decode(&s).unwrap_err() + ); + } + } +} + +#[apply(all_engines)] +fn decode_too_few_symbols_in_final_quad_error<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + // <2 is invalid + for final_quad_symbols in 0..2 { + for padding_symbols in 0..=(4 - final_quad_symbols) { + let mut s: String = "ABCD".repeat(num_prefix_quads); + + for _ in 0..final_quad_symbols { + s.push('A'); + } + for _ in 0..padding_symbols { + s.push('='); + } + + match final_quad_symbols + padding_symbols { + 0 => continue, + 1 => { + assert_eq!(DecodeError::InvalidLength, engine.decode(&s).unwrap_err()); + } + _ => { + // error reported at first padding byte + assert_eq!( + DecodeError::InvalidByte( + num_prefix_quads * 4 + final_quad_symbols, + b'=', + ), + engine.decode(&s).unwrap_err() + ); + } + } + } + } + } + } +} + +#[apply(all_engines)] +fn decode_invalid_trailing_bytes<E: EngineWrapper>(engine_wrapper: E) { + for mode in all_pad_modes() { + // we don't encode so we don't care about encode padding + let engine = E::standard_with_pad_mode(true, mode); + + for num_prefix_quads in 0..256 { + let mut s: String = "ABCD".repeat(num_prefix_quads); + s.push_str("Cg==\n"); + + // The case of trailing newlines is common enough to warrant a test for a good error + // message. + assert_eq!( + Err(DecodeError::InvalidByte(num_prefix_quads * 4 + 4, b'\n')), + engine.decode(&s) + ); + + // extra padding, however, is still InvalidLength + let s = s.replace('\n', "="); + assert_eq!(Err(DecodeError::InvalidLength), engine.decode(s)); + } + } +} + +#[apply(all_engines)] +fn decode_wrong_length_error<E: EngineWrapper>(engine_wrapper: E) { + let engine = E::standard_with_pad_mode(true, DecodePaddingMode::Indifferent); + + for num_prefix_quads in 0..256 { + // at least one token, otherwise it wouldn't be a final quad + for num_tokens_final_quad in 1..=4 { + for num_padding in 0..=(4 - num_tokens_final_quad) { + let mut s: String = "IIII".repeat(num_prefix_quads); + for _ in 0..num_tokens_final_quad { + s.push('g'); + } + for _ in 0..num_padding { + s.push('='); + } + + let res = engine.decode(&s); + if num_tokens_final_quad >= 2 { + assert!(res.is_ok()); + } else if num_tokens_final_quad == 1 && num_padding > 0 { + // = is invalid if it's too early + assert_eq!( + Err(DecodeError::InvalidByte( + num_prefix_quads * 4 + num_tokens_final_quad, + 61 + )), + res + ); + } else if num_padding > 2 { + assert_eq!(Err(DecodeError::InvalidPadding), res); + } else { + assert_eq!(Err(DecodeError::InvalidLength), res); + } + } + } + } +} + +#[apply(all_engines)] +fn decode_into_slice_fits_in_precisely_sized_slice<E: EngineWrapper>(engine_wrapper: E) { + let mut orig_data = Vec::new(); + let mut encoded_data = String::new(); + let mut decode_buf = Vec::new(); + + let input_len_range = distributions::Uniform::new(0, 1000); + let mut rng = rngs::SmallRng::from_entropy(); + + for _ in 0..10_000 { + orig_data.clear(); + encoded_data.clear(); + decode_buf.clear(); + + let input_len = input_len_range.sample(&mut rng); + + for _ in 0..input_len { + orig_data.push(rng.gen()); + } + + let engine = E::random(&mut rng); + engine.encode_string(&orig_data, &mut encoded_data); + assert_encode_sanity(&encoded_data, engine.config().encode_padding(), input_len); + + decode_buf.resize(input_len, 0); + + // decode into the non-empty buf + let decode_bytes_written = engine + .decode_slice_unchecked(encoded_data.as_bytes(), &mut decode_buf[..]) + .unwrap(); + + assert_eq!(orig_data.len(), decode_bytes_written); + assert_eq!(orig_data, decode_buf); + } +} + +#[apply(all_engines)] +fn decode_length_estimate_delta<E: EngineWrapper>(engine_wrapper: E) { + for engine in [E::standard(), E::standard_unpadded()] { + for &padding in &[true, false] { + for orig_len in 0..1000 { + let encoded_len = encoded_len(orig_len, padding).unwrap(); + + let decoded_estimate = engine + .internal_decoded_len_estimate(encoded_len) + .decoded_len_estimate(); + assert!(decoded_estimate >= orig_len); + assert!( + decoded_estimate - orig_len < 3, + "estimate: {}, encoded: {}, orig: {}", + decoded_estimate, + encoded_len, + orig_len + ); + } + } + } +} + +/// Returns a tuple of the original data length, the encoded data length (just data), and the length including padding. +/// +/// Vecs provided should be empty. +fn generate_random_encoded_data<E: Engine, R: rand::Rng, D: distributions::Distribution<usize>>( + engine: &E, + orig_data: &mut Vec<u8>, + encode_buf: &mut Vec<u8>, + rng: &mut R, + length_distribution: &D, +) -> (usize, usize, usize) { + let padding: bool = engine.config().encode_padding(); + + let orig_len = fill_rand(orig_data, rng, length_distribution); + let expected_encoded_len = encoded_len(orig_len, padding).unwrap(); + encode_buf.resize(expected_encoded_len, 0); + + let base_encoded_len = engine.internal_encode(&orig_data[..], &mut encode_buf[..]); + + let enc_len_with_padding = if padding { + base_encoded_len + add_padding(orig_len, &mut encode_buf[base_encoded_len..]) + } else { + base_encoded_len + }; + + assert_eq!(expected_encoded_len, enc_len_with_padding); + + (orig_len, base_encoded_len, enc_len_with_padding) +} + +// fill to a random length +fn fill_rand<R: rand::Rng, D: distributions::Distribution<usize>>( + vec: &mut Vec<u8>, + rng: &mut R, + length_distribution: &D, +) -> usize { + let len = length_distribution.sample(rng); + for _ in 0..len { + vec.push(rng.gen()); + } + + len +} + +fn fill_rand_len<R: rand::Rng>(vec: &mut Vec<u8>, rng: &mut R, len: usize) { + for _ in 0..len { + vec.push(rng.gen()); + } +} + +fn prefixed_data<'i, 'd>( + input_with_prefix: &'i mut String, + prefix_len: usize, + data: &'d str, +) -> &'i str { + input_with_prefix.truncate(prefix_len); + input_with_prefix.push_str(data); + input_with_prefix.as_str() +} + +/// A wrapper to make using engines in rstest fixtures easier. +/// The functions don't need to be instance methods, but rstest does seem +/// to want an instance, so instances are passed to test functions and then ignored. +trait EngineWrapper { + type Engine: Engine; + + /// Return an engine configured for RFC standard base64 + fn standard() -> Self::Engine; + + /// Return an engine configured for RFC standard base64, except with no padding appended on + /// encode, and required no padding on decode. + fn standard_unpadded() -> Self::Engine; + + /// Return an engine configured for RFC standard alphabet with the provided encode and decode + /// pad settings + fn standard_with_pad_mode(encode_pad: bool, decode_pad_mode: DecodePaddingMode) + -> Self::Engine; + + /// Return an engine configured for RFC standard base64 that allows invalid trailing bits + fn standard_allow_trailing_bits() -> Self::Engine; + + /// Return an engine configured with a randomized alphabet and config + fn random<R: rand::Rng>(rng: &mut R) -> Self::Engine; + + /// Return an engine configured with the specified alphabet and randomized config + fn random_alphabet<R: rand::Rng>(rng: &mut R, alphabet: &Alphabet) -> Self::Engine; +} + +struct GeneralPurposeWrapper {} + +impl EngineWrapper for GeneralPurposeWrapper { + type Engine = general_purpose::GeneralPurpose; + + fn standard() -> Self::Engine { + general_purpose::GeneralPurpose::new(&STANDARD, general_purpose::PAD) + } + + fn standard_unpadded() -> Self::Engine { + general_purpose::GeneralPurpose::new(&STANDARD, general_purpose::NO_PAD) + } + + fn standard_with_pad_mode( + encode_pad: bool, + decode_pad_mode: DecodePaddingMode, + ) -> Self::Engine { + general_purpose::GeneralPurpose::new( + &STANDARD, + general_purpose::GeneralPurposeConfig::new() + .with_encode_padding(encode_pad) + .with_decode_padding_mode(decode_pad_mode), + ) + } + + fn standard_allow_trailing_bits() -> Self::Engine { + general_purpose::GeneralPurpose::new( + &STANDARD, + general_purpose::GeneralPurposeConfig::new().with_decode_allow_trailing_bits(true), + ) + } + + fn random<R: rand::Rng>(rng: &mut R) -> Self::Engine { + let alphabet = random_alphabet(rng); + + Self::random_alphabet(rng, alphabet) + } + + fn random_alphabet<R: rand::Rng>(rng: &mut R, alphabet: &Alphabet) -> Self::Engine { + general_purpose::GeneralPurpose::new(alphabet, random_config(rng)) + } +} + +struct NaiveWrapper {} + +impl EngineWrapper for NaiveWrapper { + type Engine = naive::Naive; + + fn standard() -> Self::Engine { + naive::Naive::new( + &STANDARD, + naive::NaiveConfig { + encode_padding: true, + decode_allow_trailing_bits: false, + decode_padding_mode: DecodePaddingMode::RequireCanonical, + }, + ) + } + + fn standard_unpadded() -> Self::Engine { + naive::Naive::new( + &STANDARD, + naive::NaiveConfig { + encode_padding: false, + decode_allow_trailing_bits: false, + decode_padding_mode: DecodePaddingMode::RequireNone, + }, + ) + } + + fn standard_with_pad_mode( + encode_pad: bool, + decode_pad_mode: DecodePaddingMode, + ) -> Self::Engine { + naive::Naive::new( + &STANDARD, + naive::NaiveConfig { + encode_padding: false, + decode_allow_trailing_bits: false, + decode_padding_mode: decode_pad_mode, + }, + ) + } + + fn standard_allow_trailing_bits() -> Self::Engine { + naive::Naive::new( + &STANDARD, + naive::NaiveConfig { + encode_padding: true, + decode_allow_trailing_bits: true, + decode_padding_mode: DecodePaddingMode::RequireCanonical, + }, + ) + } + + fn random<R: rand::Rng>(rng: &mut R) -> Self::Engine { + let alphabet = random_alphabet(rng); + + Self::random_alphabet(rng, alphabet) + } + + fn random_alphabet<R: rand::Rng>(rng: &mut R, alphabet: &Alphabet) -> Self::Engine { + let mode = rng.gen(); + + let config = naive::NaiveConfig { + encode_padding: match mode { + DecodePaddingMode::Indifferent => rng.gen(), + DecodePaddingMode::RequireCanonical => true, + DecodePaddingMode::RequireNone => false, + }, + decode_allow_trailing_bits: rng.gen(), + decode_padding_mode: mode, + }; + + naive::Naive::new(alphabet, config) + } +} + +fn seeded_rng() -> impl rand::Rng { + rngs::SmallRng::from_entropy() +} + +fn all_pad_modes() -> Vec<DecodePaddingMode> { + vec![ + DecodePaddingMode::Indifferent, + DecodePaddingMode::RequireCanonical, + DecodePaddingMode::RequireNone, + ] +} + +fn assert_all_suffixes_ok<E: Engine>(engine: E, suffixes: Vec<&str>) { + for num_prefix_quads in 0..256 { + for &suffix in suffixes.iter() { + let mut encoded = "AAAA".repeat(num_prefix_quads); + encoded.push_str(suffix); + + let res = &engine.decode(&encoded); + assert!(res.is_ok()); + } + } +} |