X-Git-Url: http://git.euphorik.ch/?p=crypto_lab1.git;a=blobdiff_plain;f=src%2Fpacket.rs;h=74bf102ea209ca10663f7629af270284f4b041a5;hp=49ae2be0f46e066bf5d1808ef0e2359bf59910f1;hb=8226b0eced022af21512d87902bf6e252afe1a67;hpb=db8678377c7ea4fa7183a54c1bfe095e051882a8 diff --git a/src/packet.rs b/src/packet.rs index 49ae2be..74bf102 100644 --- a/src/packet.rs +++ b/src/packet.rs @@ -1,20 +1,22 @@ use std::io; use std::fmt; -use std::rand::{ random, task_rng, distributions }; +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), - UnknownPacketTypeReadError, // If the first byte is unknown. + 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. @@ -41,53 +43,74 @@ 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)] +#[deriving(Show, Clone)] pub struct PacketData { id: u8, payload: Vec // The size can vary from 'MIN_PAYLOAD_SIZE' to 'MAX_PAYLOAD_SIZE' bytes. } -#[deriving(Show)] +#[deriving(Show, Clone)] pub enum ErrorType { CryptError, AuthError } -#[deriving(Show)] +#[deriving(Clone)] pub enum PacketType { Command(PacketData), Answer(PacketData), Error(ErrorType), } +/// Serialized packet format : |LL|P|TTTTTTTT|D...D|MMMMMMMMMM| +/// Where: +/// LL: Size on 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 ans answer packet +/// |"0000000000"| for error packet +#[deriving(Show)] pub struct Packet { pub t: PacketType, pub timestamp: u64 } -impl fmt::Show for Packet { +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) + format!("id: {}, payload({}): \"{}\"", data.id, data.payload.len(), data.payload.as_slice().to_hex()) } - match self.t { - Command(ref data) => write!(formatter, "Command packet {{ timestamp: {}, {} }}", self.timestamp, data_to_str(data)), - Answer(ref data) => write!(formatter, "Answer packet {{ timestamp: {}, {} }}", self.timestamp, data_to_str(data)), - Error(error_type) => write!(formatter, "Error packet {{ timestamp: {}, errorType: {} }}", self.timestamp, error_type) + 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() -> PacketData { - let mut rng = task_rng(); + 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: random::(), - payload: Vec::from_fn(distributions::Range::new(MIN_PAYLOAD_SIZE, MAX_PAYLOAD_SIZE + 1).ind_sample(&mut rng), |_| random::()) + id: rng.gen::(), + payload: payload } } - pub fn write(&self, output: &mut io::Writer) -> WritingResult { + pub fn write(&self, output: &mut io::Writer) -> WritingResult { fn packet_data(p: &PacketData) -> Vec { let mut d = Vec::new(); d.push(p.id); @@ -143,8 +166,19 @@ impl Packet { } 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()); - let packet_type = try_read_io!(input.read_u8()); + + // 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); @@ -180,23 +214,23 @@ impl Packet { Ok(Packet { t: match packet_type { - 0x00 | 0xFF => { + // 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) } }, - 0x0A | 0x0B => { + // Error. + _ => { if data.len() != 16 { return Err(UnconsistentDataSizeError) } else if data != Vec::from_elem(16, '0' as u8) { return Err(DataError) } match packet_type { 0x0A => Error(CryptError), _ => Error(AuthError) } - }, - _ => - return Err(UnknownPacketTypeReadError) + } }, timestamp: timestamp })