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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Encoding and decoding packets off the wire.
use std::{
cmp::min,
fmt,
ops::{Deref, DerefMut, Range},
time::Instant,
};
use neqo_common::{hex, hex_with_len, qtrace, qwarn, Decoder, Encoder};
use neqo_crypto::random;
use crate::{
cid::{ConnectionId, ConnectionIdDecoder, ConnectionIdRef, MAX_CONNECTION_ID_LEN},
crypto::{CryptoDxState, CryptoSpace, CryptoStates},
frame::FRAME_TYPE_PADDING,
recovery::SendProfile,
version::{Version, WireVersion},
Error, Pmtud, Res,
};
/// `MIN_INITIAL_PACKET_SIZE` is the smallest packet that can be used to establish
/// a new connection across all QUIC versions this server supports.
pub const MIN_INITIAL_PACKET_SIZE: usize = 1200;
pub const PACKET_BIT_LONG: u8 = 0x80;
const PACKET_BIT_SHORT: u8 = 0x00;
const PACKET_BIT_FIXED_QUIC: u8 = 0x40;
const PACKET_BIT_SPIN: u8 = 0x20;
const PACKET_BIT_KEY_PHASE: u8 = 0x04;
const PACKET_HP_MASK_LONG: u8 = 0x0f;
const PACKET_HP_MASK_SHORT: u8 = 0x1f;
const SAMPLE_SIZE: usize = 16;
const SAMPLE_OFFSET: usize = 4;
const MAX_PACKET_NUMBER_LEN: usize = 4;
mod retry;
pub type PacketNumber = u64;
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PacketType {
VersionNegotiation,
Initial,
Handshake,
ZeroRtt,
Retry,
Short,
OtherVersion,
}
impl PacketType {
#[must_use]
fn from_byte(t: u8, v: Version) -> Self {
// Version2 adds one to the type, modulo 4
match t.wrapping_sub(u8::from(v == Version::Version2)) & 3 {
0 => Self::Initial,
1 => Self::ZeroRtt,
2 => Self::Handshake,
3 => Self::Retry,
_ => panic!("packet type out of range"),
}
}
#[must_use]
fn to_byte(self, v: Version) -> u8 {
let t = match self {
Self::Initial => 0,
Self::ZeroRtt => 1,
Self::Handshake => 2,
Self::Retry => 3,
_ => panic!("not a long header packet type"),
};
// Version2 adds one to the type, modulo 4
(t + u8::from(v == Version::Version2)) & 3
}
}
#[allow(clippy::fallible_impl_from)]
impl From<PacketType> for CryptoSpace {
fn from(v: PacketType) -> Self {
match v {
PacketType::Initial => Self::Initial,
PacketType::ZeroRtt => Self::ZeroRtt,
PacketType::Handshake => Self::Handshake,
PacketType::Short => Self::ApplicationData,
_ => panic!("shouldn't be here"),
}
}
}
impl From<CryptoSpace> for PacketType {
fn from(cs: CryptoSpace) -> Self {
match cs {
CryptoSpace::Initial => Self::Initial,
CryptoSpace::ZeroRtt => Self::ZeroRtt,
CryptoSpace::Handshake => Self::Handshake,
CryptoSpace::ApplicationData => Self::Short,
}
}
}
struct PacketBuilderOffsets {
/// The bits of the first octet that need masking.
first_byte_mask: u8,
/// The offset of the length field.
len: usize,
/// The location of the packet number field.
pn: Range<usize>,
}
/// A packet builder that can be used to produce short packets and long packets.
/// This does not produce Retry or Version Negotiation.
pub struct PacketBuilder {
encoder: Encoder,
pn: PacketNumber,
header: Range<usize>,
offsets: PacketBuilderOffsets,
limit: usize,
/// Whether to pad the packet before construction.
padding: bool,
}
impl PacketBuilder {
/// The minimum useful frame size. If space is less than this, we will claim to be full.
pub const MINIMUM_FRAME_SIZE: usize = 2;
fn infer_limit(encoder: &Encoder) -> usize {
if encoder.capacity() > 64 {
encoder.capacity()
} else {
2048
}
}
/// Start building a short header packet.
///
/// This doesn't fail if there isn't enough space; instead it returns a builder that
/// has no available space left. This allows the caller to extract the encoder
/// and any packets that might have been added before as adding a packet header is
/// only likely to fail if there are other packets already written.
///
/// If, after calling this method, `remaining()` returns 0, then call `abort()` to get
/// the encoder back.
pub fn short(mut encoder: Encoder, key_phase: bool, dcid: Option<impl AsRef<[u8]>>) -> Self {
let mut limit = Self::infer_limit(&encoder);
let header_start = encoder.len();
// Check that there is enough space for the header.
// 5 = 1 (first byte) + 4 (packet number)
if limit > encoder.len()
&& 5 + dcid.as_ref().map_or(0, |d| d.as_ref().len()) < limit - encoder.len()
{
encoder
.encode_byte(PACKET_BIT_SHORT | PACKET_BIT_FIXED_QUIC | (u8::from(key_phase) << 2));
if let Some(dcid) = dcid {
encoder.encode(dcid.as_ref());
}
} else {
limit = 0;
}
Self {
encoder,
pn: u64::MAX,
header: header_start..header_start,
offsets: PacketBuilderOffsets {
first_byte_mask: PACKET_HP_MASK_SHORT,
pn: 0..0,
len: 0,
},
limit,
padding: false,
}
}
/// Start building a long header packet.
/// For an Initial packet you will need to call `initial_token()`,
/// even if the token is empty.
///
/// See `short()` for more on how to handle this in cases where there is no space.
#[allow(clippy::similar_names)]
pub fn long(
mut encoder: Encoder,
pt: PacketType,
version: Version,
mut dcid: Option<impl AsRef<[u8]>>,
mut scid: Option<impl AsRef<[u8]>>,
) -> Self {
let mut limit = Self::infer_limit(&encoder);
let header_start = encoder.len();
// Check that there is enough space for the header.
// 11 = 1 (first byte) + 4 (version) + 2 (dcid+scid length) + 4 (packet number)
if limit > encoder.len()
&& 11
+ dcid.as_ref().map_or(0, |d| d.as_ref().len())
+ scid.as_ref().map_or(0, |d| d.as_ref().len())
< limit - encoder.len()
{
encoder.encode_byte(PACKET_BIT_LONG | PACKET_BIT_FIXED_QUIC | pt.to_byte(version) << 4);
encoder.encode_uint(4, version.wire_version());
encoder.encode_vec(1, dcid.take().as_ref().map_or(&[], AsRef::as_ref));
encoder.encode_vec(1, scid.take().as_ref().map_or(&[], AsRef::as_ref));
} else {
limit = 0;
}
Self {
encoder,
pn: u64::MAX,
header: header_start..header_start,
offsets: PacketBuilderOffsets {
first_byte_mask: PACKET_HP_MASK_LONG,
pn: 0..0,
len: 0,
},
limit,
padding: false,
}
}
fn is_long(&self) -> bool {
self.as_ref()[self.header.start] & 0x80 == PACKET_BIT_LONG
}
/// This stores a value that can be used as a limit. This does not cause
/// this limit to be enforced until encryption occurs. Prior to that, it
/// is only used voluntarily by users of the builder, through `remaining()`.
pub fn set_limit(&mut self, limit: usize) {
self.limit = limit;
}
/// Set the initial limit for the packet, based on the profile and the PMTUD state.
/// Returns true if the packet needs padding.
pub fn set_initial_limit(
&mut self,
profile: &SendProfile,
aead_expansion: usize,
pmtud: &Pmtud,
) -> bool {
if pmtud.needs_probe() {
debug_assert!(pmtud.probe_size() > profile.limit());
self.limit = pmtud.probe_size() - aead_expansion;
true
} else {
self.limit = profile.limit() - aead_expansion;
false
}
}
/// Get the current limit.
#[must_use]
pub const fn limit(&self) -> usize {
self.limit
}
/// How many bytes remain against the size limit for the builder.
#[must_use]
pub fn remaining(&self) -> usize {
self.limit.saturating_sub(self.encoder.len())
}
/// Returns true if the packet has no more space for frames.
#[must_use]
pub fn is_full(&self) -> bool {
// No useful frame is smaller than 2 bytes long.
self.limit < self.encoder.len() + Self::MINIMUM_FRAME_SIZE
}
/// Adjust the limit to ensure that no more data is added.
pub fn mark_full(&mut self) {
self.limit = self.encoder.len();
}
/// Mark the packet as needing padding (or not).
pub fn enable_padding(&mut self, needs_padding: bool) {
self.padding = needs_padding;
}
/// Maybe pad with "PADDING" frames.
/// Only does so if padding was needed and this is a short packet.
/// Returns true if padding was added.
///
/// # Panics
///
/// Cannot happen.
pub fn pad(&mut self) -> bool {
if self.padding && !self.is_long() {
self.encoder
.pad_to(self.limit, FRAME_TYPE_PADDING.try_into().unwrap());
true
} else {
false
}
}
/// Add unpredictable values for unprotected parts of the packet.
pub fn scramble(&mut self, quic_bit: bool) {
debug_assert!(self.len() > self.header.start);
let mask = if quic_bit { PACKET_BIT_FIXED_QUIC } else { 0 }
| if self.is_long() { 0 } else { PACKET_BIT_SPIN };
let first = self.header.start;
self.encoder.as_mut()[first] ^= random::<1>()[0] & mask;
}
/// For an Initial packet, encode the token.
/// If you fail to do this, then you will not get a valid packet.
pub fn initial_token(&mut self, token: &[u8]) {
if Encoder::vvec_len(token.len()) < self.remaining() {
self.encoder.encode_vvec(token);
} else {
self.limit = 0;
}
}
/// Add a packet number of the given size.
/// For a long header packet, this also inserts a dummy length.
/// The length is filled in after calling `build`.
/// Does nothing if there isn't 4 bytes available other than render this builder
/// unusable; if `remaining()` returns 0 at any point, call `abort()`.
///
/// # Panics
///
/// This will panic if the packet number length is too large.
pub fn pn(&mut self, pn: PacketNumber, pn_len: usize) {
if self.remaining() < 4 {
self.limit = 0;
return;
}
// Reserve space for a length in long headers.
if self.is_long() {
self.offsets.len = self.encoder.len();
self.encoder.encode(&[0; 2]);
}
// This allows the input to be >4, which is absurd, but we can eat that.
let pn_len = min(MAX_PACKET_NUMBER_LEN, pn_len);
debug_assert_ne!(pn_len, 0);
// Encode the packet number and save its offset.
let pn_offset = self.encoder.len();
self.encoder.encode_uint(pn_len, pn);
self.offsets.pn = pn_offset..self.encoder.len();
// Now encode the packet number length and save the header length.
self.encoder.as_mut()[self.header.start] |= u8::try_from(pn_len - 1).unwrap();
self.header.end = self.encoder.len();
self.pn = pn;
}
#[allow(clippy::cast_possible_truncation)] // Nope.
fn write_len(&mut self, expansion: usize) {
let len = self.encoder.len() - (self.offsets.len + 2) + expansion;
self.encoder.as_mut()[self.offsets.len] = 0x40 | ((len >> 8) & 0x3f) as u8;
self.encoder.as_mut()[self.offsets.len + 1] = (len & 0xff) as u8;
}
fn pad_for_crypto(&mut self, crypto: &CryptoDxState) {
// Make sure that there is enough data in the packet.
// The length of the packet number plus the payload length needs to
// be at least 4 (MAX_PACKET_NUMBER_LEN) plus any amount by which
// the header protection sample exceeds the AEAD expansion.
let crypto_pad = crypto.extra_padding();
self.encoder.pad_to(
self.offsets.pn.start + MAX_PACKET_NUMBER_LEN + crypto_pad,
0,
);
}
/// A lot of frames here are just a collection of varints.
/// This helper functions writes a frame like that safely, returning `true` if
/// a frame was written.
pub fn write_varint_frame(&mut self, values: &[u64]) -> bool {
let write = self.remaining()
>= values
.iter()
.map(|&v| Encoder::varint_len(v))
.sum::<usize>();
if write {
for v in values {
self.encode_varint(*v);
}
debug_assert!(self.len() <= self.limit());
};
write
}
/// Build the packet and return the encoder.
///
/// # Errors
///
/// This will return an error if the packet is too large.
pub fn build(mut self, crypto: &mut CryptoDxState) -> Res<Encoder> {
if self.len() > self.limit {
qwarn!("Packet contents are more than the limit");
debug_assert!(false);
return Err(Error::InternalError);
}
self.pad_for_crypto(crypto);
if self.offsets.len > 0 {
self.write_len(crypto.expansion());
}
let hdr = &self.encoder.as_ref()[self.header.clone()];
let body = &self.encoder.as_ref()[self.header.end..];
qtrace!(
"Packet build pn={} hdr={} body={}",
self.pn,
hex(hdr),
hex(body)
);
let ciphertext = crypto.encrypt(self.pn, hdr, body)?;
// Calculate the mask.
let offset = SAMPLE_OFFSET - self.offsets.pn.len();
if offset + SAMPLE_SIZE > ciphertext.len() {
return Err(Error::InternalError);
}
let sample = &ciphertext[offset..offset + SAMPLE_SIZE];
let mask = crypto.compute_mask(sample)?;
// Apply the mask.
self.encoder.as_mut()[self.header.start] ^= mask[0] & self.offsets.first_byte_mask;
for (i, j) in (1..=self.offsets.pn.len()).zip(self.offsets.pn) {
self.encoder.as_mut()[j] ^= mask[i];
}
// Finally, cut off the plaintext and add back the ciphertext.
self.encoder.truncate(self.header.end);
self.encoder.encode(&ciphertext);
qtrace!("Packet built {}", hex(&self.encoder));
Ok(self.encoder)
}
/// Abort writing of this packet and return the encoder.
#[must_use]
pub fn abort(mut self) -> Encoder {
self.encoder.truncate(self.header.start);
self.encoder
}
/// Work out if nothing was added after the header.
#[must_use]
pub fn packet_empty(&self) -> bool {
self.encoder.len() == self.header.end
}
/// Make a retry packet.
/// As this is a simple packet, this is just an associated function.
/// As Retry is odd (it has to be constructed with leading bytes),
/// this returns a [`Vec<u8>`] rather than building on an encoder.
///
/// # Errors
///
/// This will return an error if AEAD encrypt fails.
#[allow(clippy::similar_names)]
pub fn retry(
version: Version,
dcid: &[u8],
scid: &[u8],
token: &[u8],
odcid: &[u8],
) -> Res<Vec<u8>> {
let mut encoder = Encoder::default();
encoder.encode_vec(1, odcid);
let start = encoder.len();
encoder.encode_byte(
PACKET_BIT_LONG
| PACKET_BIT_FIXED_QUIC
| (PacketType::Retry.to_byte(version) << 4)
| (random::<1>()[0] & 0xf),
);
encoder.encode_uint(4, version.wire_version());
encoder.encode_vec(1, dcid);
encoder.encode_vec(1, scid);
debug_assert_ne!(token.len(), 0);
encoder.encode(token);
let tag = retry::use_aead(version, |aead| {
let mut buf = vec![0; aead.expansion()];
Ok(aead.encrypt(0, encoder.as_ref(), &[], &mut buf)?.to_vec())
})?;
encoder.encode(&tag);
let mut complete: Vec<u8> = encoder.into();
Ok(complete.split_off(start))
}
/// Make a Version Negotiation packet.
#[must_use]
#[allow(clippy::similar_names)]
pub fn version_negotiation(
dcid: &[u8],
scid: &[u8],
client_version: u32,
versions: &[Version],
) -> Vec<u8> {
let mut encoder = Encoder::default();
let mut grease = random::<4>();
// This will not include the "QUIC bit" sometimes. Intentionally.
encoder.encode_byte(PACKET_BIT_LONG | (grease[3] & 0x7f));
encoder.encode(&[0; 4]); // Zero version == VN.
encoder.encode_vec(1, dcid);
encoder.encode_vec(1, scid);
for v in versions {
encoder.encode_uint(4, v.wire_version());
}
// Add a greased version, using the randomness already generated.
for g in &mut grease[..3] {
*g = *g & 0xf0 | 0x0a;
}
// Ensure our greased version does not collide with the client version
// by making the last byte differ from the client initial.
grease[3] = (client_version.wrapping_add(0x10) & 0xf0) as u8 | 0x0a;
encoder.encode(&grease[..4]);
Vec::from(encoder)
}
}
impl Deref for PacketBuilder {
type Target = Encoder;
fn deref(&self) -> &Self::Target {
&self.encoder
}
}
impl DerefMut for PacketBuilder {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.encoder
}
}
impl From<PacketBuilder> for Encoder {
fn from(v: PacketBuilder) -> Self {
v.encoder
}
}
/// `PublicPacket` holds information from packets that is public only. This allows for
/// processing of packets prior to decryption.
pub struct PublicPacket<'a> {
/// The packet type.
packet_type: PacketType,
/// The recovered destination connection ID.
dcid: ConnectionIdRef<'a>,
/// The source connection ID, if this is a long header packet.
scid: Option<ConnectionIdRef<'a>>,
/// Any token that is included in the packet (Retry always has a token; Initial sometimes
/// does). This is empty when there is no token.
token: &'a [u8],
/// The size of the header, not including the packet number.
header_len: usize,
/// Protocol version, if present in header.
version: Option<WireVersion>,
/// A reference to the entire packet, including the header.
data: &'a [u8],
}
impl<'a> PublicPacket<'a> {
fn opt<T>(v: Option<T>) -> Res<T> {
v.map_or_else(|| Err(Error::NoMoreData), |v| Ok(v))
}
/// Decode the type-specific portions of a long header.
/// This includes reading the length and the remainder of the packet.
/// Returns a tuple of any token and the length of the header.
fn decode_long(
decoder: &mut Decoder<'a>,
packet_type: PacketType,
version: Version,
) -> Res<(&'a [u8], usize)> {
if packet_type == PacketType::Retry {
let header_len = decoder.offset();
let expansion = retry::expansion(version);
let token = decoder
.remaining()
.checked_sub(expansion)
.map_or(Err(Error::InvalidPacket), |v| Self::opt(decoder.decode(v)))?;
if token.is_empty() {
return Err(Error::InvalidPacket);
}
Self::opt(decoder.decode(expansion))?;
return Ok((token, header_len));
}
let token = if packet_type == PacketType::Initial {
Self::opt(decoder.decode_vvec())?
} else {
&[]
};
let len = Self::opt(decoder.decode_varint())?;
let header_len = decoder.offset();
let _body = Self::opt(decoder.decode(usize::try_from(len)?))?;
Ok((token, header_len))
}
/// Decode the common parts of a packet. This provides minimal parsing and validation.
/// Returns a tuple of a `PublicPacket` and a slice with any remainder from the datagram.
///
/// # Errors
///
/// This will return an error if the packet could not be decoded.
#[allow(clippy::similar_names)]
pub fn decode(data: &'a [u8], dcid_decoder: &dyn ConnectionIdDecoder) -> Res<(Self, &'a [u8])> {
let mut decoder = Decoder::new(data);
let first = Self::opt(decoder.decode_byte())?;
if first & 0x80 == PACKET_BIT_SHORT {
// Conveniently, this also guarantees that there is enough space
// for a connection ID of any size.
if decoder.remaining() < SAMPLE_OFFSET + SAMPLE_SIZE {
return Err(Error::InvalidPacket);
}
let dcid = Self::opt(dcid_decoder.decode_cid(&mut decoder))?;
if decoder.remaining() < SAMPLE_OFFSET + SAMPLE_SIZE {
return Err(Error::InvalidPacket);
}
let header_len = decoder.offset();
return Ok((
Self {
packet_type: PacketType::Short,
dcid,
scid: None,
token: &[],
header_len,
version: None,
data,
},
&[],
));
}
// Generic long header.
let version = WireVersion::try_from(Self::opt(decoder.decode_uint(4))?)?;
let dcid = ConnectionIdRef::from(Self::opt(decoder.decode_vec(1))?);
let scid = ConnectionIdRef::from(Self::opt(decoder.decode_vec(1))?);
// Version negotiation.
if version == 0 {
return Ok((
Self {
packet_type: PacketType::VersionNegotiation,
dcid,
scid: Some(scid),
token: &[],
header_len: decoder.offset(),
version: None,
data,
},
&[],
));
}
// Check that this is a long header from a supported version.
let Ok(version) = Version::try_from(version) else {
return Ok((
Self {
packet_type: PacketType::OtherVersion,
dcid,
scid: Some(scid),
token: &[],
header_len: decoder.offset(),
version: Some(version),
data,
},
&[],
));
};
if dcid.len() > MAX_CONNECTION_ID_LEN || scid.len() > MAX_CONNECTION_ID_LEN {
return Err(Error::InvalidPacket);
}
let packet_type = PacketType::from_byte((first >> 4) & 3, version);
// The type-specific code includes a token. This consumes the remainder of the packet.
let (token, header_len) = Self::decode_long(&mut decoder, packet_type, version)?;
let end = data.len() - decoder.remaining();
let (data, remainder) = data.split_at(end);
Ok((
Self {
packet_type,
dcid,
scid: Some(scid),
token,
header_len,
version: Some(version.wire_version()),
data,
},
remainder,
))
}
/// Validate the given packet as though it were a retry.
#[must_use]
pub fn is_valid_retry(&self, odcid: &ConnectionId) -> bool {
if self.packet_type != PacketType::Retry {
return false;
}
let Some(version) = self.version() else {
return false;
};
let expansion = retry::expansion(version);
if self.data.len() <= expansion {
return false;
}
let (header, tag) = self.data.split_at(self.data.len() - expansion);
let mut encoder = Encoder::with_capacity(self.data.len());
encoder.encode_vec(1, odcid);
encoder.encode(header);
retry::use_aead(version, |aead| {
let mut buf = vec![0; expansion];
Ok(aead.decrypt(0, encoder.as_ref(), tag, &mut buf)?.is_empty())
})
.unwrap_or(false)
}
#[must_use]
pub fn is_valid_initial(&self) -> bool {
// Packet has to be an initial, with a DCID of 8 bytes, or a token.
// Note: the Server class validates the token and checks the length.
self.packet_type == PacketType::Initial
&& (self.dcid().len() >= 8 || !self.token.is_empty())
}
#[must_use]
pub const fn packet_type(&self) -> PacketType {
self.packet_type
}
#[must_use]
pub const fn dcid(&self) -> ConnectionIdRef<'a> {
self.dcid
}
/// # Panics
///
/// This will panic if called for a short header packet.
#[must_use]
pub fn scid(&self) -> ConnectionIdRef<'a> {
self.scid
.expect("should only be called for long header packets")
}
#[must_use]
pub const fn token(&self) -> &'a [u8] {
self.token
}
#[must_use]
pub fn version(&self) -> Option<Version> {
self.version.and_then(|v| Version::try_from(v).ok())
}
#[must_use]
pub fn wire_version(&self) -> WireVersion {
debug_assert!(self.version.is_some());
self.version.unwrap_or(0)
}
#[must_use]
pub const fn len(&self) -> usize {
self.data.len()
}
const fn decode_pn(expected: PacketNumber, pn: u64, w: usize) -> PacketNumber {
let window = 1_u64 << (w * 8);
let candidate = (expected & !(window - 1)) | pn;
if candidate + (window / 2) <= expected {
candidate + window
} else if candidate > expected + (window / 2) {
match candidate.checked_sub(window) {
Some(pn_sub) => pn_sub,
None => candidate,
}
} else {
candidate
}
}
/// Decrypt the header of the packet.
fn decrypt_header(
&self,
crypto: &CryptoDxState,
) -> Res<(bool, PacketNumber, Vec<u8>, &'a [u8])> {
assert_ne!(self.packet_type, PacketType::Retry);
assert_ne!(self.packet_type, PacketType::VersionNegotiation);
let sample_offset = self.header_len + SAMPLE_OFFSET;
let mask = self
.data
.get(sample_offset..(sample_offset + SAMPLE_SIZE))
.map_or(Err(Error::NoMoreData), |sample| {
qtrace!("unmask hdr={}", hex(&self.data[..sample_offset]));
crypto.compute_mask(sample)
})?;
// Un-mask the leading byte.
let bits = if self.packet_type == PacketType::Short {
PACKET_HP_MASK_SHORT
} else {
PACKET_HP_MASK_LONG
};
let first_byte = self.data[0] ^ (mask[0] & bits);
// Make a copy of the header to work on.
let mut hdrbytes = self.data[..self.header_len + 4].to_vec();
hdrbytes[0] = first_byte;
// Unmask the PN.
let mut pn_encoded: u64 = 0;
for i in 0..MAX_PACKET_NUMBER_LEN {
hdrbytes[self.header_len + i] ^= mask[1 + i];
pn_encoded <<= 8;
pn_encoded += u64::from(hdrbytes[self.header_len + i]);
}
// Now decode the packet number length and apply it, hopefully in constant time.
let pn_len = usize::from((first_byte & 0x3) + 1);
hdrbytes.truncate(self.header_len + pn_len);
pn_encoded >>= 8 * (MAX_PACKET_NUMBER_LEN - pn_len);
qtrace!("unmasked hdr={}", hex(&hdrbytes));
let key_phase = self.packet_type == PacketType::Short
&& (first_byte & PACKET_BIT_KEY_PHASE) == PACKET_BIT_KEY_PHASE;
let pn = Self::decode_pn(crypto.next_pn(), pn_encoded, pn_len);
Ok((
key_phase,
pn,
hdrbytes,
&self.data[self.header_len + pn_len..],
))
}
/// # Errors
///
/// This will return an error if the packet cannot be decrypted.
pub fn decrypt(&self, crypto: &mut CryptoStates, release_at: Instant) -> Res<DecryptedPacket> {
let cspace: CryptoSpace = self.packet_type.into();
// When we don't have a version, the crypto code doesn't need a version
// for lookup, so use the default, but fix it up if decryption succeeds.
let version = self.version().unwrap_or_default();
// This has to work in two stages because we need to remove header protection
// before picking the keys to use.
if let Some(rx) = crypto.rx_hp(version, cspace) {
// Note that this will dump early, which creates a side-channel.
// This is OK in this case because we the only reason this can
// fail is if the cryptographic module is bad or the packet is
// too small (which is public information).
let (key_phase, pn, header, body) = self.decrypt_header(rx)?;
qtrace!([rx], "decoded header: {:?}", header);
let Some(rx) = crypto.rx(version, cspace, key_phase) else {
return Err(Error::DecryptError);
};
let version = rx.version(); // Version fixup; see above.
let d = rx.decrypt(pn, &header, body)?;
// If this is the first packet ever successfully decrypted
// using `rx`, make sure to initiate a key update.
if rx.needs_update() {
crypto.key_update_received(release_at)?;
}
crypto.check_pn_overlap()?;
Ok(DecryptedPacket {
version,
pt: self.packet_type,
pn,
data: d,
})
} else if crypto.rx_pending(cspace) {
Err(Error::KeysPending(cspace))
} else {
qtrace!("keys for {:?} already discarded", cspace);
Err(Error::KeysDiscarded(cspace))
}
}
/// # Errors
///
/// This will return an error if the packet is not a version negotiation packet
/// or if the versions cannot be decoded.
pub fn supported_versions(&self) -> Res<Vec<WireVersion>> {
if self.packet_type != PacketType::VersionNegotiation {
return Err(Error::InvalidPacket);
}
let mut decoder = Decoder::new(&self.data[self.header_len..]);
let mut res = Vec::new();
while decoder.remaining() > 0 {
let version = WireVersion::try_from(Self::opt(decoder.decode_uint(4))?)?;
res.push(version);
}
Ok(res)
}
}
impl fmt::Debug for PublicPacket<'_> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"{:?}: {} {}",
self.packet_type(),
hex_with_len(&self.data[..self.header_len]),
hex_with_len(&self.data[self.header_len..])
)
}
}
pub struct DecryptedPacket {
version: Version,
pt: PacketType,
pn: PacketNumber,
data: Vec<u8>,
}
impl DecryptedPacket {
#[must_use]
pub const fn version(&self) -> Version {
self.version
}
#[must_use]
pub const fn packet_type(&self) -> PacketType {
self.pt
}
#[must_use]
pub const fn pn(&self) -> PacketNumber {
self.pn
}
}
impl Deref for DecryptedPacket {
type Target = [u8];
fn deref(&self) -> &Self::Target {
&self.data[..]
}
}
#[cfg(all(test, not(feature = "disable-encryption")))]
mod tests {
use neqo_common::Encoder;
use test_fixture::{fixture_init, now};
use crate::{
cid::MAX_CONNECTION_ID_LEN,
crypto::{CryptoDxState, CryptoStates},
packet::{
PacketBuilder, PacketType, PublicPacket, PACKET_BIT_FIXED_QUIC, PACKET_BIT_LONG,
PACKET_BIT_SPIN,
},
ConnectionId, EmptyConnectionIdGenerator, RandomConnectionIdGenerator, Version,
};
const CLIENT_CID: &[u8] = &[0x83, 0x94, 0xc8, 0xf0, 0x3e, 0x51, 0x57, 0x08];
const SERVER_CID: &[u8] = &[0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5];
/// This is a connection ID manager, which is only used for decoding short header packets.
const fn cid_mgr() -> RandomConnectionIdGenerator {
RandomConnectionIdGenerator::new(SERVER_CID.len())
}
const SAMPLE_INITIAL_PAYLOAD: &[u8] = &[
0x02, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x40, 0x5a, 0x02, 0x00, 0x00, 0x56, 0x03, 0x03,
0xee, 0xfc, 0xe7, 0xf7, 0xb3, 0x7b, 0xa1, 0xd1, 0x63, 0x2e, 0x96, 0x67, 0x78, 0x25, 0xdd,
0xf7, 0x39, 0x88, 0xcf, 0xc7, 0x98, 0x25, 0xdf, 0x56, 0x6d, 0xc5, 0x43, 0x0b, 0x9a, 0x04,
0x5a, 0x12, 0x00, 0x13, 0x01, 0x00, 0x00, 0x2e, 0x00, 0x33, 0x00, 0x24, 0x00, 0x1d, 0x00,
0x20, 0x9d, 0x3c, 0x94, 0x0d, 0x89, 0x69, 0x0b, 0x84, 0xd0, 0x8a, 0x60, 0x99, 0x3c, 0x14,
0x4e, 0xca, 0x68, 0x4d, 0x10, 0x81, 0x28, 0x7c, 0x83, 0x4d, 0x53, 0x11, 0xbc, 0xf3, 0x2b,
0xb9, 0xda, 0x1a, 0x00, 0x2b, 0x00, 0x02, 0x03, 0x04,
];
const SAMPLE_INITIAL: &[u8] = &[
0xcf, 0x00, 0x00, 0x00, 0x01, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x00, 0x40, 0x75, 0xc0, 0xd9, 0x5a, 0x48, 0x2c, 0xd0, 0x99, 0x1c, 0xd2, 0x5b, 0x0a, 0xac,
0x40, 0x6a, 0x58, 0x16, 0xb6, 0x39, 0x41, 0x00, 0xf3, 0x7a, 0x1c, 0x69, 0x79, 0x75, 0x54,
0x78, 0x0b, 0xb3, 0x8c, 0xc5, 0xa9, 0x9f, 0x5e, 0xde, 0x4c, 0xf7, 0x3c, 0x3e, 0xc2, 0x49,
0x3a, 0x18, 0x39, 0xb3, 0xdb, 0xcb, 0xa3, 0xf6, 0xea, 0x46, 0xc5, 0xb7, 0x68, 0x4d, 0xf3,
0x54, 0x8e, 0x7d, 0xde, 0xb9, 0xc3, 0xbf, 0x9c, 0x73, 0xcc, 0x3f, 0x3b, 0xde, 0xd7, 0x4b,
0x56, 0x2b, 0xfb, 0x19, 0xfb, 0x84, 0x02, 0x2f, 0x8e, 0xf4, 0xcd, 0xd9, 0x37, 0x95, 0xd7,
0x7d, 0x06, 0xed, 0xbb, 0x7a, 0xaf, 0x2f, 0x58, 0x89, 0x18, 0x50, 0xab, 0xbd, 0xca, 0x3d,
0x20, 0x39, 0x8c, 0x27, 0x64, 0x56, 0xcb, 0xc4, 0x21, 0x58, 0x40, 0x7d, 0xd0, 0x74, 0xee,
];
#[test]
fn sample_server_initial() {
fixture_init();
let mut prot = CryptoDxState::test_default();
// The spec uses PN=1, but our crypto refuses to skip packet numbers.
// So burn an encryption:
let burn = prot.encrypt(0, &[], &[]).expect("burn OK");
assert_eq!(burn.len(), prot.expansion());
let mut builder = PacketBuilder::long(
Encoder::new(),
PacketType::Initial,
Version::default(),
None::<&[u8]>,
Some(ConnectionId::from(SERVER_CID)),
);
builder.initial_token(&[]);
builder.pn(1, 2);
builder.encode(SAMPLE_INITIAL_PAYLOAD);
let packet = builder.build(&mut prot).expect("build");
assert_eq!(packet.as_ref(), SAMPLE_INITIAL);
}
#[test]
fn decrypt_initial() {
const EXTRA: &[u8] = &[0xce; 33];
fixture_init();
let mut padded = SAMPLE_INITIAL.to_vec();
padded.extend_from_slice(EXTRA);
let (packet, remainder) = PublicPacket::decode(&padded, &cid_mgr()).unwrap();
assert_eq!(packet.packet_type(), PacketType::Initial);
assert_eq!(&packet.dcid()[..], &[] as &[u8]);
assert_eq!(&packet.scid()[..], SERVER_CID);
assert!(packet.token().is_empty());
assert_eq!(remainder, EXTRA);
let decrypted = packet
.decrypt(&mut CryptoStates::test_default(), now())
.unwrap();
assert_eq!(decrypted.pn(), 1);
}
#[test]
fn disallow_long_dcid() {
let mut enc = Encoder::new();
enc.encode_byte(PACKET_BIT_LONG | PACKET_BIT_FIXED_QUIC);
enc.encode_uint(4, Version::default().wire_version());
enc.encode_vec(1, &[0x00; MAX_CONNECTION_ID_LEN + 1]);
enc.encode_vec(1, &[]);
enc.encode(&[0xff; 40]); // junk
assert!(PublicPacket::decode(enc.as_ref(), &cid_mgr()).is_err());
}
#[test]
fn disallow_long_scid() {
let mut enc = Encoder::new();
enc.encode_byte(PACKET_BIT_LONG | PACKET_BIT_FIXED_QUIC);
enc.encode_uint(4, Version::default().wire_version());
enc.encode_vec(1, &[]);
enc.encode_vec(1, &[0x00; MAX_CONNECTION_ID_LEN + 2]);
enc.encode(&[0xff; 40]); // junk
assert!(PublicPacket::decode(enc.as_ref(), &cid_mgr()).is_err());
}
const SAMPLE_SHORT: &[u8] = &[
0x40, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5, 0xf4, 0xa8, 0x30, 0x39, 0xc4, 0x7d,
0x99, 0xe3, 0x94, 0x1c, 0x9b, 0xb9, 0x7a, 0x30, 0x1d, 0xd5, 0x8f, 0xf3, 0xdd, 0xa9,
];
const SAMPLE_SHORT_PAYLOAD: &[u8] = &[0; 3];
#[test]
fn build_short() {
fixture_init();
let mut builder =
PacketBuilder::short(Encoder::new(), true, Some(ConnectionId::from(SERVER_CID)));
builder.pn(0, 1);
builder.encode(SAMPLE_SHORT_PAYLOAD); // Enough payload for sampling.
let packet = builder
.build(&mut CryptoDxState::test_default())
.expect("build");
assert_eq!(packet.as_ref(), SAMPLE_SHORT);
}
#[test]
fn scramble_short() {
fixture_init();
let mut firsts = Vec::new();
for _ in 0..64 {
let mut builder =
PacketBuilder::short(Encoder::new(), true, Some(ConnectionId::from(SERVER_CID)));
builder.scramble(true);
builder.pn(0, 1);
firsts.push(builder.as_ref()[0]);
}
let is_set = |bit| move |v| v & bit == bit;
// There should be at least one value with the QUIC bit set:
assert!(firsts.iter().any(is_set(PACKET_BIT_FIXED_QUIC)));
// ... but not all:
assert!(!firsts.iter().all(is_set(PACKET_BIT_FIXED_QUIC)));
// There should be at least one value with the spin bit set:
assert!(firsts.iter().any(is_set(PACKET_BIT_SPIN)));
// ... but not all:
assert!(!firsts.iter().all(is_set(PACKET_BIT_SPIN)));
}
#[test]
fn decode_short() {
fixture_init();
let (packet, remainder) = PublicPacket::decode(SAMPLE_SHORT, &cid_mgr()).unwrap();
assert_eq!(packet.packet_type(), PacketType::Short);
assert!(remainder.is_empty());
let decrypted = packet
.decrypt(&mut CryptoStates::test_default(), now())
.unwrap();
assert_eq!(&decrypted[..], SAMPLE_SHORT_PAYLOAD);
}
/// By telling the decoder that the connection ID is shorter than it really is, we get a
/// decryption error.
#[test]
fn decode_short_bad_cid() {
fixture_init();
let (packet, remainder) = PublicPacket::decode(
SAMPLE_SHORT,
&RandomConnectionIdGenerator::new(SERVER_CID.len() - 1),
)
.unwrap();
assert_eq!(packet.packet_type(), PacketType::Short);
assert!(remainder.is_empty());
assert!(packet
.decrypt(&mut CryptoStates::test_default(), now())
.is_err());
}
/// Saying that the connection ID is longer causes the initial decode to fail.
#[test]
fn decode_short_long_cid() {
assert!(PublicPacket::decode(
SAMPLE_SHORT,
&RandomConnectionIdGenerator::new(SERVER_CID.len() + 1)
)
.is_err());
}
#[test]
fn build_two() {
fixture_init();
let mut prot = CryptoDxState::test_default();
let mut builder = PacketBuilder::long(
Encoder::new(),
PacketType::Handshake,
Version::default(),
Some(ConnectionId::from(SERVER_CID)),
Some(ConnectionId::from(CLIENT_CID)),
);
builder.pn(0, 1);
builder.encode(&[0; 3]);
let encoder = builder.build(&mut prot).expect("build");
assert_eq!(encoder.len(), 45);
let first = encoder.clone();
let mut builder =
PacketBuilder::short(encoder, false, Some(ConnectionId::from(SERVER_CID)));
builder.pn(1, 3);
builder.encode(&[0]); // Minimal size (packet number is big enough).
let encoder = builder.build(&mut prot).expect("build");
assert_eq!(
first.as_ref(),
&encoder.as_ref()[..first.len()],
"the first packet should be a prefix"
);
assert_eq!(encoder.len(), 45 + 29);
}
#[test]
fn build_long() {
const EXPECTED: &[u8] = &[
0xe4, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x40, 0x14, 0xfb, 0xa9, 0x32, 0x3a, 0xf8,
0xbb, 0x18, 0x63, 0xc6, 0xbd, 0x78, 0x0e, 0xba, 0x0c, 0x98, 0x65, 0x58, 0xc9, 0x62,
0x31,
];
fixture_init();
let mut builder = PacketBuilder::long(
Encoder::new(),
PacketType::Handshake,
Version::default(),
None::<&[u8]>,
None::<&[u8]>,
);
builder.pn(0, 1);
builder.encode(&[1, 2, 3]);
let packet = builder.build(&mut CryptoDxState::test_default()).unwrap();
assert_eq!(packet.as_ref(), EXPECTED);
}
#[test]
fn scramble_long() {
fixture_init();
let mut found_unset = false;
let mut found_set = false;
for _ in 1..64 {
let mut builder = PacketBuilder::long(
Encoder::new(),
PacketType::Handshake,
Version::default(),
None::<&[u8]>,
None::<&[u8]>,
);
builder.pn(0, 1);
builder.scramble(true);
if (builder.as_ref()[0] & PACKET_BIT_FIXED_QUIC) == 0 {
found_unset = true;
} else {
found_set = true;
}
}
assert!(found_unset);
assert!(found_set);
}
#[test]
fn build_abort() {
let mut builder = PacketBuilder::long(
Encoder::new(),
PacketType::Initial,
Version::default(),
None::<&[u8]>,
Some(ConnectionId::from(SERVER_CID)),
);
assert_ne!(builder.remaining(), 0);
builder.initial_token(&[]);
assert_ne!(builder.remaining(), 0);
builder.pn(1, 2);
assert_ne!(builder.remaining(), 0);
let encoder = builder.abort();
assert!(encoder.is_empty());
}
#[test]
fn build_insufficient_space() {
fixture_init();
let mut builder = PacketBuilder::short(
Encoder::with_capacity(100),
true,
Some(ConnectionId::from(SERVER_CID)),
);
builder.pn(0, 1);
// Pad, but not up to the full capacity. Leave enough space for the
// AEAD expansion and some extra, but not for an entire long header.
builder.set_limit(75);
builder.enable_padding(true);
assert!(builder.pad());
let encoder = builder.build(&mut CryptoDxState::test_default()).unwrap();
let encoder_copy = encoder.clone();
let builder = PacketBuilder::long(
encoder,
PacketType::Initial,
Version::default(),
Some(ConnectionId::from(SERVER_CID)),
Some(ConnectionId::from(SERVER_CID)),
);
assert_eq!(builder.remaining(), 0);
assert_eq!(builder.abort(), encoder_copy);
}
const SAMPLE_RETRY_V2: &[u8] = &[
0xcf, 0x6b, 0x33, 0x43, 0xcf, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x74, 0x6f, 0x6b, 0x65, 0x6e, 0xc8, 0x64, 0x6c, 0xe8, 0xbf, 0xe3, 0x39, 0x52, 0xd9, 0x55,
0x54, 0x36, 0x65, 0xdc, 0xc7, 0xb6,
];
const SAMPLE_RETRY_V1: &[u8] = &[
0xff, 0x00, 0x00, 0x00, 0x01, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x04, 0xa2, 0x65, 0xba, 0x2e, 0xff, 0x4d, 0x82, 0x90, 0x58,
0xfb, 0x3f, 0x0f, 0x24, 0x96, 0xba,
];
const SAMPLE_RETRY_29: &[u8] = &[
0xff, 0xff, 0x00, 0x00, 0x1d, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x74, 0x6f, 0x6b, 0x65, 0x6e, 0xd1, 0x69, 0x26, 0xd8, 0x1f, 0x6f, 0x9c, 0xa2, 0x95, 0x3a,
0x8a, 0xa4, 0x57, 0x5e, 0x1e, 0x49,
];
const SAMPLE_RETRY_30: &[u8] = &[
0xff, 0xff, 0x00, 0x00, 0x1e, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x2d, 0x3e, 0x04, 0x5d, 0x6d, 0x39, 0x20, 0x67, 0x89, 0x94,
0x37, 0x10, 0x8c, 0xe0, 0x0a, 0x61,
];
const SAMPLE_RETRY_31: &[u8] = &[
0xff, 0xff, 0x00, 0x00, 0x1f, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x74, 0x6f, 0x6b, 0x65, 0x6e, 0xc7, 0x0c, 0xe5, 0xde, 0x43, 0x0b, 0x4b, 0xdb, 0x7d, 0xf1,
0xa3, 0x83, 0x3a, 0x75, 0xf9, 0x86,
];
const SAMPLE_RETRY_32: &[u8] = &[
0xff, 0xff, 0x00, 0x00, 0x20, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5,
0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x59, 0x75, 0x65, 0x19, 0xdd, 0x6c, 0xc8, 0x5b, 0xd9, 0x0e,
0x33, 0xa9, 0x34, 0xd2, 0xff, 0x85,
];
const RETRY_TOKEN: &[u8] = b"token";
fn build_retry_single(version: Version, sample_retry: &[u8]) {
fixture_init();
let retry =
PacketBuilder::retry(version, &[], SERVER_CID, RETRY_TOKEN, CLIENT_CID).unwrap();
let (packet, remainder) = PublicPacket::decode(&retry, &cid_mgr()).unwrap();
assert!(packet.is_valid_retry(&ConnectionId::from(CLIENT_CID)));
assert!(remainder.is_empty());
// The builder adds randomness, which makes expectations hard.
// So only do a full check when that randomness matches up.
if retry[0] == sample_retry[0] {
assert_eq!(&retry, &sample_retry);
} else {
// Otherwise, just check that the header is OK.
assert_eq!(
retry[0] & 0xf0,
0xc0 | (PacketType::Retry.to_byte(version) << 4)
);
let header_range = 1..retry.len() - 16;
assert_eq!(&retry[header_range.clone()], &sample_retry[header_range]);
}
}
#[test]
fn build_retry_v2() {
build_retry_single(Version::Version2, SAMPLE_RETRY_V2);
}
#[test]
fn build_retry_v1() {
build_retry_single(Version::Version1, SAMPLE_RETRY_V1);
}
#[test]
fn build_retry_29() {
build_retry_single(Version::Draft29, SAMPLE_RETRY_29);
}
#[test]
fn build_retry_30() {
build_retry_single(Version::Draft30, SAMPLE_RETRY_30);
}
#[test]
fn build_retry_31() {
build_retry_single(Version::Draft31, SAMPLE_RETRY_31);
}
#[test]
fn build_retry_32() {
build_retry_single(Version::Draft32, SAMPLE_RETRY_32);
}
#[test]
fn build_retry_multiple() {
// Run the build_retry test a few times.
// Odds are approximately 1 in 8 that the full comparison doesn't happen
// for a given version.
for _ in 0..32 {
build_retry_v2();
build_retry_v1();
build_retry_29();
build_retry_30();
build_retry_31();
build_retry_32();
}
}
fn decode_retry(version: Version, sample_retry: &[u8]) {
fixture_init();
let (packet, remainder) =
PublicPacket::decode(sample_retry, &RandomConnectionIdGenerator::new(5)).unwrap();
assert!(packet.is_valid_retry(&ConnectionId::from(CLIENT_CID)));
assert_eq!(Some(version), packet.version());
assert!(packet.dcid().is_empty());
assert_eq!(&packet.scid()[..], SERVER_CID);
assert_eq!(packet.token(), RETRY_TOKEN);
assert!(remainder.is_empty());
}
#[test]
fn decode_retry_v2() {
decode_retry(Version::Version2, SAMPLE_RETRY_V2);
}
#[test]
fn decode_retry_v1() {
decode_retry(Version::Version1, SAMPLE_RETRY_V1);
}
#[test]
fn decode_retry_29() {
decode_retry(Version::Draft29, SAMPLE_RETRY_29);
}
#[test]
fn decode_retry_30() {
decode_retry(Version::Draft30, SAMPLE_RETRY_30);
}
#[test]
fn decode_retry_31() {
decode_retry(Version::Draft31, SAMPLE_RETRY_31);
}
#[test]
fn decode_retry_32() {
decode_retry(Version::Draft32, SAMPLE_RETRY_32);
}
/// Check some packets that are clearly not valid Retry packets.
#[test]
fn invalid_retry() {
fixture_init();
let cid_mgr = RandomConnectionIdGenerator::new(5);
let odcid = ConnectionId::from(CLIENT_CID);
assert!(PublicPacket::decode(&[], &cid_mgr).is_err());
let (packet, remainder) = PublicPacket::decode(SAMPLE_RETRY_V1, &cid_mgr).unwrap();
assert!(remainder.is_empty());
assert!(packet.is_valid_retry(&odcid));
let mut damaged_retry = SAMPLE_RETRY_V1.to_vec();
let last = damaged_retry.len() - 1;
damaged_retry[last] ^= 66;
let (packet, remainder) = PublicPacket::decode(&damaged_retry, &cid_mgr).unwrap();
assert!(remainder.is_empty());
assert!(!packet.is_valid_retry(&odcid));
damaged_retry.truncate(last);
let (packet, remainder) = PublicPacket::decode(&damaged_retry, &cid_mgr).unwrap();
assert!(remainder.is_empty());
assert!(!packet.is_valid_retry(&odcid));
// An invalid token should be rejected sooner.
damaged_retry.truncate(last - 4);
assert!(PublicPacket::decode(&damaged_retry, &cid_mgr).is_err());
damaged_retry.truncate(last - 1);
assert!(PublicPacket::decode(&damaged_retry, &cid_mgr).is_err());
}
const SAMPLE_VN: &[u8] = &[
0x80, 0x00, 0x00, 0x00, 0x00, 0x08, 0xf0, 0x67, 0xa5, 0x50, 0x2a, 0x42, 0x62, 0xb5, 0x08,
0x83, 0x94, 0xc8, 0xf0, 0x3e, 0x51, 0x57, 0x08, 0x6b, 0x33, 0x43, 0xcf, 0x00, 0x00, 0x00,
0x01, 0xff, 0x00, 0x00, 0x20, 0xff, 0x00, 0x00, 0x1f, 0xff, 0x00, 0x00, 0x1e, 0xff, 0x00,
0x00, 0x1d, 0x0a, 0x0a, 0x0a, 0x0a,
];
#[test]
fn build_vn() {
fixture_init();
let mut vn = PacketBuilder::version_negotiation(
SERVER_CID,
CLIENT_CID,
0x0a0a_0a0a,
&Version::all(),
);
// Erase randomness from greasing...
assert_eq!(vn.len(), SAMPLE_VN.len());
vn[0] &= 0x80;
for v in vn.iter_mut().skip(SAMPLE_VN.len() - 4) {
*v &= 0x0f;
}
assert_eq!(&vn, &SAMPLE_VN);
}
#[test]
fn vn_do_not_repeat_client_grease() {
fixture_init();
let vn = PacketBuilder::version_negotiation(
SERVER_CID,
CLIENT_CID,
0x0a0a_0a0a,
&Version::all(),
);
assert_ne!(&vn[SAMPLE_VN.len() - 4..], &[0x0a, 0x0a, 0x0a, 0x0a]);
}
#[test]
fn parse_vn() {
let (packet, remainder) =
PublicPacket::decode(SAMPLE_VN, &EmptyConnectionIdGenerator::default()).unwrap();
assert!(remainder.is_empty());
assert_eq!(&packet.dcid[..], SERVER_CID);
assert!(packet.scid.is_some());
assert_eq!(&packet.scid.unwrap()[..], CLIENT_CID);
}
/// A Version Negotiation packet can have a long connection ID.
#[test]
fn parse_vn_big_cid() {
const BIG_DCID: &[u8] = &[0x44; MAX_CONNECTION_ID_LEN + 1];
const BIG_SCID: &[u8] = &[0xee; 255];
let mut enc = Encoder::from(&[0xff, 0x00, 0x00, 0x00, 0x00][..]);
enc.encode_vec(1, BIG_DCID);
enc.encode_vec(1, BIG_SCID);
enc.encode_uint(4, 0x1a2a_3a4a_u64);
enc.encode_uint(4, Version::default().wire_version());
enc.encode_uint(4, 0x5a6a_7a8a_u64);
let (packet, remainder) =
PublicPacket::decode(enc.as_ref(), &EmptyConnectionIdGenerator::default()).unwrap();
assert!(remainder.is_empty());
assert_eq!(&packet.dcid[..], BIG_DCID);
assert!(packet.scid.is_some());
assert_eq!(&packet.scid.unwrap()[..], BIG_SCID);
}
#[test]
fn decode_pn() {
// When the expected value is low, the value doesn't go negative.
assert_eq!(PublicPacket::decode_pn(0, 0, 1), 0);
assert_eq!(PublicPacket::decode_pn(0, 0xff, 1), 0xff);
assert_eq!(PublicPacket::decode_pn(10, 0, 1), 0);
assert_eq!(PublicPacket::decode_pn(0x7f, 0, 1), 0);
assert_eq!(PublicPacket::decode_pn(0x80, 0, 1), 0x100);
assert_eq!(PublicPacket::decode_pn(0x80, 2, 1), 2);
assert_eq!(PublicPacket::decode_pn(0x80, 0xff, 1), 0xff);
assert_eq!(PublicPacket::decode_pn(0x7ff, 0xfe, 1), 0x7fe);
// This is invalid by spec, as we are expected to check for overflow around 2^62-1,
// but we don't need to worry about overflow
// and hitting this is basically impossible in practice.
assert_eq!(
PublicPacket::decode_pn(0x3fff_ffff_ffff_ffff, 2, 4),
0x4000_0000_0000_0002
);
}
#[test]
fn chacha20_sample() {
const PACKET: &[u8] = &[
0x4c, 0xfe, 0x41, 0x89, 0x65, 0x5e, 0x5c, 0xd5, 0x5c, 0x41, 0xf6, 0x90, 0x80, 0x57,
0x5d, 0x79, 0x99, 0xc2, 0x5a, 0x5b, 0xfb,
];
fixture_init();
let (packet, slice) =
PublicPacket::decode(PACKET, &EmptyConnectionIdGenerator::default()).unwrap();
assert!(slice.is_empty());
let decrypted = packet
.decrypt(&mut CryptoStates::test_chacha(), now())
.unwrap();
assert_eq!(decrypted.packet_type(), PacketType::Short);
assert_eq!(decrypted.pn(), 654_360_564);
assert_eq!(&decrypted[..], &[0x01]);
}
#[test]
fn decode_empty() {
neqo_crypto::init().unwrap();
let res = PublicPacket::decode(&[], &EmptyConnectionIdGenerator::default());
assert!(res.is_err());
}
#[test]
fn decode_too_short() {
neqo_crypto::init().unwrap();
let res = PublicPacket::decode(
&[179, 255, 0, 0, 32, 0, 0],
&EmptyConnectionIdGenerator::default(),
);
assert!(res.is_err());
}
}