X-Git-Url: http://git.euphorik.ch/?p=crypto_lab1.git;a=blobdiff_plain;f=src%2Fpacket.rs;h=ece32c49f62cced2bb1548371c35db24af9592f7;hp=74bf102ea209ca10663f7629af270284f4b041a5;hb=786dd3ba778ac05917b00e42e8d82929db9fa529;hpb=8226b0eced022af21512d87902bf6e252afe1a67 diff --git a/src/packet.rs b/src/packet.rs index 74bf102..ece32c4 100644 --- a/src/packet.rs +++ b/src/packet.rs @@ -10,11 +10,11 @@ use crypto; pub enum ReadingError { IOReadError(io::IoError), UnknownPacketTypeError, // If the first byte is unknown. - UnconsistentEncryptedSizeError, + 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. + MACMismatchError, // The uncrypted received data doesn't match to the received MAC. + PaddingError, // Padding format error. DataError, // The data are invalid. InvalidTimestampError } @@ -104,94 +104,110 @@ impl Packet { 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 { + PacketData { id: rng.gen::(), payload: payload } } + pub fn new_packet_data(id: u8, payload: Vec) -> PacketData { + PacketData { id: id, payload: payload } + } + pub fn write(&self, output: &mut io::Writer) -> WritingResult { + self.write_with_padding_fun(output, |_: uint, padding_length: uint| -> u8 { + padding_length as u8 + }) + } + + /// 'padd_fun' is function to fill 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 { let mut d = Vec::new(); d.push(p.id); d.push_all(p.payload.as_slice()); d } - - // Data to be encrypted. - let mut data = + + // 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' as u8) // Padding as data: 16 * '0'. }; - + // Compute the MAC - let mac = crypto::compute_mac(data.as_slice()); - + let mac = crypto::compute_mac(data.as_slice()); + // Padding. match self.t { Command(_) | Answer(_) => { let padding_size = if data.len() % 16 == 0 { 16 } else { data.len() % 16 } ; - data.push_all(Vec::from_elem(padding_size, padding_size as u8).as_slice()); + data.reserve_additional(padding_size); + for i in range(0, padding_size) { + data.push(padd_fun(i, padding_size)); + } }, _ => () } - + // Encrypt. - let encrypted_data = crypto::encrypt(data.as_slice(), iv_from_timestamp(self.timestamp).as_slice()); - + let encrypted_data = crypto::encrypt(data.as_slice(), iv_from_timestamp(self.timestamp).as_slice()); + // 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 + 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 _ = 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()); + 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); + + 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 = crypto::decrypt(encrypted_data.as_slice(), iv_from_timestamp(timestamp).as_slice()); - - // Control the size and the content of the padding then remove it. + + // 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) => { + 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; @@ -201,7 +217,7 @@ impl Packet { 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() { @@ -211,7 +227,7 @@ impl Packet { if mac_read != mac_data { return Err(MACMismatchError) } - + Ok(Packet { t: match packet_type { // Command or answer. @@ -223,13 +239,13 @@ impl Packet { match packet_type { 0x00 => Command(pd), _ => Answer(pd) } }, // Error. - _ => { + _ => { if data.len() != 16 { return Err(UnconsistentDataSizeError) - } else if data != Vec::from_elem(16, '0' as u8) { + } else if data != Vec::from_elem(16, '0' as u8) { return Err(DataError) } - match packet_type { 0x0A => Error(CryptError), _ => Error(AuthError) } + match packet_type { 0x0A => Error(CryptError), _ => Error(AuthError) } } }, timestamp: timestamp