From: Ummon <greg.burri@gmail.com>
Date: Tue, 4 Nov 2014 12:15:17 +0000 (+0100)
Subject: Begining of the machine oracle (work in progress..)
X-Git-Url: https://git.euphorik.ch/?a=commitdiff_plain;h=c9318a07ce0ec00f999ff17943b83048d536ecd1;p=crypto_lab1.git

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

diff --git a/src/crypto.rs b/src/crypto.rs
index 35c7b48..d9fe182 100644
--- a/src/crypto.rs
+++ b/src/crypto.rs
@@ -5,9 +5,11 @@ use openssl::crypto::hash::SHA256;
 use openssl::crypto::hmac::HMAC;
 use openssl::crypto::symm;
 
+// These aren't the keys you're looking for.
 static KEY_A: &'static [u8] = [125, 31, 131, 118, 143, 180, 252, 53, 211, 217, 79, 240, 128, 91, 252, 87, 104, 236, 145, 198, 163, 203, 161, 12, 53, 56, 218, 40, 221, 95, 171, 140];
 static KEY_C: &'static [u8] = [75, 226, 88, 31, 223, 216, 182, 216, 178, 58, 59, 193, 245, 80, 254, 128, 125, 246, 246, 224, 194, 190, 123, 123, 10, 131, 217, 183, 112, 157, 166, 102];
 
+/// Only returns the first ten bytes.
 pub fn compute_mac(data: &[u8]) -> [u8, ..10] {
    let mut hmac = HMAC(SHA256, KEY_A);
    hmac.update(data);
@@ -16,11 +18,12 @@ pub fn compute_mac(data: &[u8]) -> [u8, ..10] {
    result
 }
 
+/// Encrypt may fail if the provided data size isn't a multiple of 16.
 pub fn encrypt(plaindata: &[u8], iv: &[u8]) -> Option<Vec<u8>> {
    let c = symm::Crypter::new(symm::AES_256_CBC);
    c.init(symm::Encrypt, KEY_C, iv.to_vec());
    c.pad(false); // Padding disabled!
-   let mut r = c.update(plaindata);
+   let r = c.update(plaindata);
    let rest = c.finalize();
    if rest.is_empty() {
       Some(r)
@@ -29,11 +32,12 @@ pub fn encrypt(plaindata: &[u8], iv: &[u8]) -> Option<Vec<u8>> {
    }
 }
 
+/// Decrypt may fail if the provided data size isn't a multiple of 16.
 pub fn decrypt(cypherdata: &[u8], iv: &[u8]) -> Option<Vec<u8>> {
    let c = symm::Crypter::new(symm::AES_256_CBC);
    c.init(symm::Decrypt, KEY_C, iv.to_vec());
    c.pad(false); // Padding disabled!
-   let mut r = c.update(cypherdata);
+   let r = c.update(cypherdata);
    let rest = c.finalize();
    if rest.is_empty() {
       Some(r)
diff --git a/src/end_point.rs b/src/end_point.rs
index 71f217e..2d0a66c 100644
--- a/src/end_point.rs
+++ b/src/end_point.rs
@@ -15,7 +15,7 @@ pub struct Client {
    end_point: EndPoint,
 }
 
-struct EndPoint {
+pub struct EndPoint {
    socket: TcpStream,
    current_timestamp: u64
 }
@@ -33,7 +33,7 @@ impl Server {
             for stream in acceptor.incoming() {
                match stream {
                   Ok(stream) => spawn(proc() {
-                     Server::handle_client(EndPoint { socket: stream, current_timestamp: 0 });
+                     Server::handle_client(EndPoint::new(stream));
                   }),
                   _ => return
                }
@@ -246,6 +246,10 @@ impl Client {
 }
 
 impl EndPoint {
+   pub fn new(socket: TcpStream) -> EndPoint {
+      EndPoint { socket: socket, current_timestamp: 0 }
+   }
+
    fn close(&mut self) -> IoResult<()> {
       try!(self.socket.close_read());
       try!(self.socket.close_write());
diff --git a/src/main.rs b/src/main.rs
index 1fae4c1..64aef28 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -11,11 +11,19 @@ use end_point::{ Client, Server };
 mod crypto;
 mod packet;
 mod end_point;
+mod oracle_machine;
 
 const PORT: u16 = 4221;
 
 fn print_usage() {
-   println!("{} <genkey> | <tests> | ...", os::args()[0]);
+   println!(
+      r"{} genkey | tests | oracle-weak | oracle-fixed
+   genkey: Generate a 256 bits key
+   tests: launch some tests between a client and a weak server
+   oracle-weak: launch a padding oracle attack against a weak server
+   oracle-fixed: launch a padding oracle attack against a fixed server",
+      os::args()[0]
+   );
 }
 
 fn main() {
@@ -35,7 +43,9 @@ fn main() {
          Ok(mut server) => {
             println!("Server started");
 
-            Client::start_tests("::1", PORT);
+            if args.len() > 1 && args[1].as_slice() == "tests" {
+               Client::start_tests("::1", PORT);
+            }
 
             println!("Press any key to quit");
             io::stdin().read_line().ok().expect("Failed to read line");
diff --git a/src/oracle_machine.rs b/src/oracle_machine.rs
new file mode 100644
index 0000000..68aef94
--- /dev/null
+++ b/src/oracle_machine.rs
@@ -0,0 +1,19 @@
+use std::io;
+use std::io::{ TcpStream };
+use end_point::EndPoint;
+
+/// Try to decypher a cyphered data block by using an oracle on the provided address and port.
+/// May prints some message on the stdout.
+pub fn decypher(address: &str, port: u16, cypherblock: [u8, ..16]) -> Option<Vec<u8>> {
+   let end_point = EndPoint::new(
+      match TcpStream::connect(address, port) {
+         Ok(s) => s,
+         _ => {
+            println!("Unable to connect to the oracle on {}:{}", address, port);
+            return None
+         }
+      }
+   );
+
+   None
+}