Begining of the machine oracle (work in progress..)

[crypto_lab1.git] / src / packet.rs

diff --git a/src/packet.rs b/src/packet.rs
index ece32c4..73eecea 100644 (file)
--- a/src/packet.rs
+++ b/src/packet.rs
@@ -27,8 +27,8 @@ macro_rules! try_read_io(
 // There are all the errors that may occur when encrypting, authenticating and writing a packet.
 #[deriving(Show)]
 pub enum WritingError {
-   WriteIOError(io::IoError)
-   // TODO...
+   WriteIOError(io::IoError),
+   EncryptError,
 }
 
 // A macro to return a 'IOWritingError' in case of error.
@@ -64,7 +64,7 @@ pub enum PacketType {
 
 /// Serialized packet format : |LL|P|TTTTTTTT|D...D|MMMMMMMMMM|
 /// Where:
-///   LL: Size on the following data
+///   LL: Size of the following data
 ///   P: Packet type:
 ///      0x00: Command
 ///      OxFF: Answer
@@ -76,10 +76,10 @@ pub enum PacketType {
 ///            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)
+///         |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
+///      |I|C...C| for command and answer packet
+///      |0000000000000000| for error packet
 #[deriving(Show)]
 pub struct Packet {
    pub t: PacketType,
@@ -115,12 +115,12 @@ impl Packet {
    }
 
    pub fn write(&self, output: &mut io::Writer) -> WritingResult {
-      self.write_with_padding_fun(output, |_: uint, padding_length: uint| -> u8 {
+      self.write_with_padding_fun(output, |_, 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.
+   /// '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> {
@@ -134,7 +134,7 @@ impl Packet {
       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'.
+            Error(_) => Vec::from_elem(16, 0) // Padding as data: 16 * 0.
          };
 
       // Compute the MAC
@@ -143,7 +143,7 @@ impl Packet {
       // Padding.
       match self.t {
          Command(_) | Answer(_) => {
-            let padding_size = if data.len() % 16 == 0 { 16 } else { data.len() % 16 } ;
+            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));
@@ -153,7 +153,10 @@ impl Packet {
       }
 
       // Encrypt.
-      let encrypted_data = crypto::encrypt(data.as_slice(), iv_from_timestamp(self.timestamp).as_slice());
+      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));
@@ -200,7 +203,10 @@ impl Packet {
       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());
+      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 {
@@ -242,7 +248,7 @@ impl Packet {
             _ => {
                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) {
                   return Err(DataError)
                }
                match packet_type { 0x0A => Error(CryptError), _ => Error(AuthError) }