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Fix minimum MAC size this fixes a deserialization error #1159

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Oct 31, 2023
Merged

Fix minimum MAC size this fixes a deserialization error #1159

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42 changes: 0 additions & 42 deletions ntp-proto/src/packet/extension_fields.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1253,48 +1253,6 @@ mod tests {
assert_eq!(slice.len(), 28 + 16);
}

#[test]
fn deserialize_without_cipher_invalid_length() {
// the message will be smaller than the cutoff value of 28
let cookie = ExtensionField::NtsCookie(Cow::Borrowed(&[0; 4]));

let data = ExtensionFieldData {
authenticated: vec![],
encrypted: vec![cookie],
untrusted: vec![],
};

let nonce_length = 11;
let cipher = crate::packet::crypto::IdentityCipher::new(nonce_length);

let mut w = [0u8; 128];
let mut cursor = Cursor::new(w.as_mut_slice());
data.serialize(&mut cursor, &cipher, ExtensionHeaderVersion::V4)
.unwrap();

let n = cursor.position() as usize;
let slice = &w.as_slice()[..n];

let cipher = crate::packet::crypto::NoCipher;

let result =
ExtensionFieldData::deserialize(slice, 0, &cipher, ExtensionHeaderVersion::V4).unwrap();

let DeserializedExtensionField {
efdata,
remaining_bytes,
cookie,
} = result;

assert_eq!(efdata.authenticated, &[]);
assert_eq!(efdata.encrypted, &[]);
assert_eq!(efdata.untrusted, &[]);

assert_eq!(remaining_bytes, slice);

assert!(cookie.is_none());
}

#[test]
fn deserialize_without_cipher() {
let cookie = ExtensionField::NtsCookie(Cow::Borrowed(&[0; 32]));
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6 changes: 5 additions & 1 deletion ntp-proto/src/packet/mac.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,11 @@ pub(super) struct Mac<'a> {
}

impl<'a> Mac<'a> {
pub(super) const MAXIMUM_SIZE: usize = 28;
// As per RFC7822:
// If a MAC is used, it resides at the end of the packet. This field
// can be either 24 octets long, 20 octets long, or a 4-octet
// crypto-NAK.
pub(super) const MAXIMUM_SIZE: usize = 24;

pub(super) fn into_owned(self) -> Mac<'static> {
Mac {
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22 changes: 22 additions & 0 deletions ntp-proto/src/packet/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2134,6 +2134,28 @@ mod tests {
assert!(NtpPacket::deserialize(&input, &NoCipher).is_err());
}

#[test]
fn round_trip_with_ef() {
let (mut p, _) = NtpPacket::poll_message(PollInterval::default());
p.efdata.untrusted.push(ExtensionField::Unknown {
type_id: 0x42,
data: vec![].into(),
});

let serialized = p.serialize_without_encryption_vec().unwrap();

let (mut out, _) = NtpPacket::deserialize(&serialized, &NoCipher).unwrap();

// Strip any padding
let ExtensionField::Unknown { data, .. } = &mut out.efdata.untrusted[0] else {
panic!("wrong ef");
};
assert!(data.iter().all(|&e| e == 0));
*data = vec![].into();

assert_eq!(p, out);
}

#[cfg(feature = "ntpv5")]
#[test]
fn ef_with_missing_padding_v5() {
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