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Disallow extra bytes in Bitfield from_bytes (#488)

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Michael Sproul 2019-08-06 11:05:35 +10:00 committed by Paul Hauner
parent 4f45bf2255
commit 0374e31907
1 changed files with 20 additions and 0 deletions
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20
eth2/utils/ssz_types/src/bitfield.rs
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@ -161,6 +161,7 @@ impl<N: Unsigned + Clone> Bitfield<Variable<N>> {
/// ///
/// Returns `None` if `bytes` are not a valid encoding. /// Returns `None` if `bytes` are not a valid encoding.
pub fn from_bytes(bytes: Vec<u8>) -> Result<Self, Error> { pub fn from_bytes(bytes: Vec<u8>) -> Result<Self, Error> {
let bytes_len = bytes.len();
let mut initial_bitfield: Bitfield<Variable<N>> = { let mut initial_bitfield: Bitfield<Variable<N>> = {
let num_bits = bytes.len() * 8; let num_bits = bytes.len() * 8;
Bitfield::from_raw_bytes(bytes, num_bits)? Bitfield::from_raw_bytes(bytes, num_bits)?
@ -170,6 +171,14 @@ impl<N: Unsigned + Clone> Bitfield<Variable<N>> {
.highest_set_bit() .highest_set_bit()
.ok_or_else(|| Error::MissingLengthInformation)?; .ok_or_else(|| Error::MissingLengthInformation)?;
// The length bit should be in the last byte, or else it means we have too many bytes.
if len / 8 + 1 != bytes_len {
return Err(Error::InvalidByteCount {
given: bytes_len,
expected: len / 8 + 1,
});
}
if len <= Self::max_len() { if len <= Self::max_len() {
initial_bitfield initial_bitfield
.set(len, false) .set(len, false)
@ -825,6 +834,17 @@ mod bitlist {
assert!(BitList8::from_ssz_bytes(&[0b0000_0001, 0b0000_0100]).is_err()); assert!(BitList8::from_ssz_bytes(&[0b0000_0001, 0b0000_0100]).is_err());
} }
#[test]
fn ssz_decode_extra_bytes() {
assert!(BitList0::from_ssz_bytes(&[0b0000_0001, 0b0000_0000]).is_err());
assert!(BitList1::from_ssz_bytes(&[0b0000_0001, 0b0000_0000]).is_err());
assert!(BitList8::from_ssz_bytes(&[0b0000_0001, 0b0000_0000]).is_err());
assert!(BitList16::from_ssz_bytes(&[0b0000_0001, 0b0000_0000]).is_err());
assert!(BitList1024::from_ssz_bytes(&[0b1000_0000, 0]).is_err());
assert!(BitList1024::from_ssz_bytes(&[0b1000_0000, 0, 0]).is_err());
assert!(BitList1024::from_ssz_bytes(&[0b1000_0000, 0, 0, 0, 0]).is_err());
}
#[test] #[test]
fn ssz_round_trip() { fn ssz_round_trip() {
assert_round_trip(BitList0::with_capacity(0).unwrap()); assert_round_trip(BitList0::with_capacity(0).unwrap());