2 use std
::io
::{ TcpStream
};
3 use std
::iter
::{ range_inclusive
};
4 use std
::slice
::bytes
::copy_memory
;
6 use packet
::{ Packet
, Error
};
7 use end_point
::EndPoint
;
9 /// Try to decypher a cyphered data block by using the previous xor operand and an oracle on the provided address and port.
10 /// May prints some message on the stdout.
11 pub fn decypher(address
: &str, port
: u16, original_xor_operand
: &[u8, ..16], cypherblock
: &[u8, ..16], variant
: packet
::Variant
) -> Option
<Vec
<u8>> {
12 let mut end_point
= EndPoint
::new(
13 match TcpStream
::connect(address
, port
) {
16 println!("Unable to connect to the oracle on [{}]:{}", address
, port
);
23 let mut final_packet
= [0u8, ..2 + 1 + 8 + 32 + 10];
24 final_packet
[1] = 1 + 8 + 32 + 10; // Data length.
25 copy_memory(final_packet
.slice_mut(2 + 1 + 8 + 16, 2 + 1 + 8 + 32), cypherblock
);
27 let mut decypher_block
= [0u8, ..16]; // The result.
28 let mut x_prime_block
= [0u8, ..16]; // The cypher block ('cypherblock') after AES and before XOR.
29 let mut current_timestamp
= 0u64;
30 let mut first_byte
= 0u8; // Used to save the first byte for the first iteration.
33 fn forged_xor_operand(packet
: &mut [u8]) -> &mut [u8] { packet
.slice_mut(2 + 1 + 8, 2 + 1 + 8 + 16) }
38 let mut get_mac_mismatch_error
= false; // For the first byte we need to insure there is only one AUTH error (one valid padding).
40 for v
in range_inclusive(0u8, 255) { // For each values of the current byte.
42 // Compute and write timestamp.
43 current_timestamp
+= 2;
45 let mut timestamp_writer
= io
::BufWriter
::new(final_packet
.slice_mut(2 + 1, 2 + 1 + 8));
46 let _
= timestamp_writer
.write_be_u64(current_timestamp
- 1);
49 forged_xor_operand(&mut final_packet
)[byte
] = v
;
51 match end_point
.send_raw_with_result(final_packet
) {
52 Ok(Ok(Packet
{ t
: Error(packet
::AuthError
), .. })) => {
54 // If we already got a MAC mismatch for the first byte then the second byte is incremented and the loop is replayed.
55 if byte
== 15 && get_mac_mismatch_error
{
56 forged_xor_operand(&mut final_packet
)[14] += 1;
60 get_mac_mismatch_error
= true;
62 let padding_value
= 16 - byte
;
63 x_prime_block
[byte
] = v ^
(padding_value
as u8);
64 decypher_block
[byte
] = x_prime_block
[byte
] ^ original_xor_operand
[byte
];
66 // We set the processed bytes of the forged XOR operand to have the next padding value.
67 for i
in range(16 - padding_value
, 16) {
68 forged_xor_operand(&mut final_packet
)[i
] = x_prime_block
[i
] ^
((padding_value
as u8) + 1);
71 // Special case for the first byte: we have to test all the values.
73 first_byte
= forged_xor_operand(&mut final_packet
)[15];
78 Ok(Ok(Packet
{ t
: Error(packet
::CryptError
), .. })) => (), // Ignored case: the padding is wrong.
80 println!("Unexcepted response, aborting. {}", other
);
87 forged_xor_operand(&mut final_packet
)[15] = first_byte
;
90 // It was the last byte.
91 if byte
== 0 { break; }
96 Some(decypher_block
.to_vec())