+++ /dev/null
-use std::io;
-use std::fmt;
-use std::rand::{ Rng, StdRng, SeedableRng, distributions };
-use std::rand::distributions::IndependentSample;
-use serialize::hex::{ ToHex };
-use crypto;
-
-// There are all the errors that may occur when reading an encrypted and authenticated packet.
-#[deriving(Show)]
-pub enum ReadingError {
- IOReadError(io::IoError),
- UnknownPacketTypeError, // If the first byte is unknown.
- UnconsistentEncryptedSizeError,
- UnconsistentDataSizeError, // The data size is not valid.
- UnconsistentMACSizeError, // The MAC hasn't the correct size.
- MACMismatchError, // The uncrypted received data doesn't match to the received MAC.
- PaddingError, // Padding format error.
- DataError, // The data are invalid.
- InvalidTimestampError
-}
-
-// A macro to return a 'IOReadError' in case of error.
-macro_rules! try_read_io(
- ($e:expr) => (match $e { Ok(e) => e, Err(e) => return Err(IOReadError(e)) })
-)
-
-// There are all the errors that may occur when encrypting, authenticating and writing a packet.
-#[deriving(Show)]
-pub enum WritingError {
- WriteIOError(io::IoError),
- EncryptError,
-}
-
-// A macro to return a 'IOWritingError' in case of error.
-macro_rules! try_write_io(
- ($e:expr) => (match $e { Ok(e) => e, Err(e) => return Err(WriteIOError(e)) })
-)
-
-pub type ReadingResult = Result<Packet, ReadingError>;
-pub type WritingResult = Result<(), WritingError>;
-
-static MIN_PAYLOAD_SIZE: uint = 7;
-static MAX_PAYLOAD_SIZE: uint = 39;
-static FIXED_PACKET_SIZE: uint = 1 + 8 + 10; // Packet type + timestamp + MAC.
-
-#[deriving(Show, Clone)]
-pub struct PacketData {
- id: u8,
- payload: Vec<u8> // The size can vary from 'MIN_PAYLOAD_SIZE' to 'MAX_PAYLOAD_SIZE' bytes.
-}
-
-#[deriving(Show, Clone)]
-pub enum ErrorType {
- CryptError,
- AuthError
-}
-
-#[deriving(Clone)]
-pub enum PacketType {
- Command(PacketData),
- Answer(PacketData),
- Error(ErrorType),
-}
-
-/// Serialized packet format : |LL|P|TTTTTTTT|D...D|MMMMMMMMMM|
-/// Where:
-/// LL: Size of the following data
-/// P: Packet type:
-/// 0x00: Command
-/// OxFF: Answer
-/// 0x0A: Decrypt error
-/// 0x0B: Authentication error
-/// TTTTTTTT: Timestamp (64 bits)
-/// D...D: Encrypted data (AES-256 CBC mode) of:
-/// |I|C...C|P...P| for command and answer packet:
-/// I: Command ID
-/// C: Command payload (from 7 to 39 bytes)
-/// P: Padding from 1 to 16, |I|C...C|P...P| size must be a multiple of 16
-/// |0000000000000000| for error packet (16 bytes length)
-/// MMMMMMMMMM: first 10 bytes (most significant) of the HMAC-SHA256 of:
-/// |I|C...C| for command and answer packet
-/// |0000000000000000| for error packet
-#[deriving(Show)]
-pub struct Packet {
- pub t: PacketType,
- pub timestamp: u64
-}
-
-impl fmt::Show for PacketType {
- fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
- fn data_to_str(data: &PacketData) -> String {
- format!("id: {}, payload({}): \"{}\"", data.id, data.payload.len(), data.payload.as_slice().to_hex())
- }
- match self {
- &Command(ref data) => write!(formatter, "Command {{ {} }}", data_to_str(data)),
- &Answer(ref data) => write!(formatter, "Answer {{ {} }}", data_to_str(data)),
- &Error(error_type) => write!(formatter, "Error {{ errorType: {} }}", error_type)
- }
- }
-}
-
-impl Packet {
- pub fn random_packet_data(seed: &[uint]) -> PacketData {
- let mut rng = if seed.is_empty() { StdRng::new().unwrap() } else { SeedableRng::from_seed(seed) };
- let mut payload = Vec::from_elem(distributions::Range::new(MIN_PAYLOAD_SIZE, MAX_PAYLOAD_SIZE + 1).ind_sample(&mut rng), 0u8);
- rng.fill_bytes(payload.as_mut_slice_());
- PacketData {
- id: rng.gen::<u8>(),
- payload: payload
- }
- }
-
- pub fn new_packet_data(id: u8, payload: Vec<u8>) -> PacketData {
- PacketData { id: id, payload: payload }
- }
-
- pub fn write(&self, output: &mut io::Writer) -> WritingResult {
- self.write_with_padding_fun(output, |_, padding_length: uint| -> u8 {
- padding_length as u8
- })
- }
-
- /// 'padd_fun' is function defining the padding. The first argument is the index of the current byte, starting at 0.
- /// The second argument is the padding length.
- pub fn write_with_padding_fun(&self, output: &mut io::Writer, padd_fun: |uint, uint| -> u8) -> WritingResult {
- fn packet_data(p: &PacketData) -> Vec<u8> {
- let mut d = Vec::new();
- d.push(p.id);
- d.push_all(p.payload.as_slice());
- d
- }
-
- // Data to be encrypted.
- let mut data =
- match self.t {
- Command(ref p) | Answer(ref p) => packet_data(p),
- Error(_) => Vec::from_elem(16, 0) // Padding as data: 16 * 0.
- };
-
- // Compute the MAC
- let mac = crypto::compute_mac(data.as_slice());
-
- // Padding.
- match self.t {
- Command(_) | Answer(_) => {
- let padding_size = if data.len() % 16 == 0 { 16 } else { 16 - data.len() % 16 } ;
- data.reserve_additional(padding_size);
- for i in range(0, padding_size) {
- data.push(padd_fun(i, padding_size));
- }
- },
- _ => ()
- }
-
- // Encrypt.
- let encrypted_data = match crypto::encrypt(data.as_slice(), iv_from_timestamp(self.timestamp).as_slice()) {
- Some(d) => d,
- _ => return Err(EncryptError)
- };
-
- // Write packet length.
- try_write_io!(output.write_be_u16((encrypted_data.len() + FIXED_PACKET_SIZE) as u16));
-
- // Write packet type.
- try_write_io!(output.write_u8(
- match self.t {
- Command(_) => 0x00,
- Answer(_) => 0xFF,
- Error(CryptError) => 0x0A,
- Error(AuthError) => 0x0B
- }
- ));
-
- // Write timestamp.
- try_write_io!(output.write_be_u64(self.timestamp));
-
- // Write encrypted data.
- try_write_io!(output.write(encrypted_data.as_slice()));
-
- // Write the MAC.
- try_write_io!(output.write(mac));
-
- Ok(())
- }
-
- pub fn read(input: &mut io::Reader) -> ReadingResult {
- fn consume(input: &mut io::Reader, nb_byte: uint) {
- let _ = input.read_exact(nb_byte);
- }
-
- let data_size = try_read_io!(input.read_be_u16());
-
- // Read and check the packet type.
- let packet_type = try_read_io!(input.read_u8());
- if ![0x00, 0xFF, 0x0A, 0x0B].iter().any(|p| *p == packet_type) {
- consume(input, data_size as uint - 1);
- return Err(UnknownPacketTypeError)
- }
-
- let timestamp = try_read_io!(input.read_be_u64());
-
- let mut encrypted_data = Vec::from_elem(data_size as uint - FIXED_PACKET_SIZE, 0u8);
- if try_read_io!(input.read(encrypted_data.as_mut_slice_())) != encrypted_data.len() {
- return Err(UnconsistentEncryptedSizeError)
- }
- let mut data = match crypto::decrypt(encrypted_data.as_slice(), iv_from_timestamp(timestamp).as_slice()) {
- Some(d) => d,
- _ => return Err(UnconsistentEncryptedSizeError)
- };
-
- // Control the size and the content of the padding then remove it.
- if packet_type == 0x00 || packet_type == 0xFF {
- match data.last() {
- Some(&padding_size) => {
- if padding_size as uint > data.len() || !data.slice_from(data.len() - padding_size as uint).iter().any(|b| *b == padding_size) {
- consume(input, 10);
- return Err(PaddingError)
- }
- let data_length = data.len() - padding_size as uint;
- data.truncate(data_length);
- },
- None =>
- return Err(PaddingError)
- }
- }
-
- // Read an verify the MAC.
- let mut mac_read = [0u8, ..10];
- if try_read_io!(input.read(mac_read)) != mac_read.len() {
- return Err(UnconsistentMACSizeError)
- }
- let mac_data = crypto::compute_mac(data.as_slice());
- if mac_read != mac_data {
- return Err(MACMismatchError)
- }
-
- Ok(Packet {
- t: match packet_type {
- // Command or answer.
- 0x00 | 0xFF => {
- if data.len() < MIN_PAYLOAD_SIZE + 1 || data.len() > MAX_PAYLOAD_SIZE + 1 {
- return Err(UnconsistentDataSizeError)
- }
- let pd = PacketData { id: data[0], payload: data.tail().to_vec() }; // match data.as_slice() { [id, payload..] => PacketData { id: id, payload: payload.to_vec() } };
- match packet_type { 0x00 => Command(pd), _ => Answer(pd) }
- },
- // Error.
- _ => {
- if data.len() != 16 {
- return Err(UnconsistentDataSizeError)
- } else if data != Vec::from_elem(16, 0) {
- return Err(DataError)
- }
- match packet_type { 0x0A => Error(CryptError), _ => Error(AuthError) }
- }
- },
- timestamp: timestamp
- })
- }
-}
-
-// Build an initialization vector: 64 * 0u8 + timestamp (128 bits).
-fn iv_from_timestamp(timestamp: u64) -> Vec<u8> {
- let mut iv = io::MemWriter::with_capacity(16);
- let _ = iv.write_be_u64(0u64);
- let _ = iv.write_be_u64(timestamp);
- iv.unwrap()
-}
projects / crypto_lab1.git / blobdiff