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rework dearmor
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@Phaiax
Phaiax committed Jul 14, 2016
1 parent 4b860c7 commit 72b009e
Showing 1 changed file with 70 additions and 51 deletions.
121 changes: 70 additions & 51 deletions src/parse.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@ use rmp::decode;
use rmp::value::{Value, Integer};
use std::char::from_u32;

use sodiumoxide::crypto::hash::hash;

#[derive(Debug)]
pub struct Recipient {
recipient_pub: Vec<u8>,
Expand All @@ -28,71 +30,88 @@ pub enum ParseError{
NotWellFormed(String),
}

fn peel_outer_messagepack_encoding(mut raw: &mut R) -> Result<Vec<u8>, ParseError>
where R: Read {
match decode::read_value(&mut raw) {
Ok(Value::Binary(bin)) => Ok(bin),
Err(s) => Err(ParseError::NotWellFormed(format!("Not a messagepack stream. {}", s))),
_ => Err(ParseError::NotWellFormed("No nested messagepack found.".to_string()))
}
}

pub fn read_and_assert_header_v_1_0<R>(mut raw: &mut R) -> Result<SaltpackHeader10, ParseError>
where R: Read
{
let nested_binary : Vec<u8> = match decode::read_value(&mut raw) {
Ok(Value::Binary(bin)) => bin,
Err(s) => return Err(ParseError::NotWellFormed(format!("Not a messagepack stream. {}", s))),
_ => return Err(ParseError::NotWellFormed("No nested messagepack found.".to_string()))
};
where R: Read {

let mut reader : &[u8] = nested_binary.as_slice();

let arr : Vec<Value> = match decode::read_value(&mut reader) {
Ok(Value::Array(arr)) => arr,
Err(s) => return Err(ParseError::NotWellFormed(format!("Nested binary is not a messagepack stream. {}", s))),
_ => return Err(ParseError::NotWellFormed("No nested header messagepack is not of type array.".to_string()))
};
// 1 Deserialize the header bytes from the message stream using MessagePack. (What's on the wire is twice-encoded, so the result of unpacking will be once-encoded bytes.)
let nested_binary : Vec<u8> = try!(peel_outer_messagepack_encoding(&mut raw));

if arr.len() < 2 {
return Err(ParseError::NotWellFormed(format!("Header messagepack array to short. ({}<2)", arr.len())));
}
// 2 Compute the crypto_hash (SHA512) of the bytes from #1 to give the header hash.
let headerhash = hash(&header_inner_messagepack[..]);

let saltpack_str = match arr.get(0).unwrap().clone() {
Value::String(e) => e,
_ => return Err(ParseError::NotWellFormed("First header array element is not of type string.".to_string()))
};
// 3 Deserialize the bytes from #1 again using MessagePack to give the header list.
let mut reader : &[u8] = nested_binary.as_slice();

if saltpack_str != "saltpack" {
return Err(ParseError::NotWellFormed(format!("Header magic string should be 'saltpack' but is {}", saltpack_str)));
}
// 3.1 retrieve array as `arr`
let arr : Vec<Value> = match decode::read_value(&mut reader) {
Ok(Value::Array(arr)) => arr,
Err(s) => return Err(ParseError::NotWellFormed(format!("Nested binary is not a messagepack stream. {}", s))),
_ => return Err(ParseError::NotWellFormed("Nested header messagepack is not of type array.".to_string()))
};

let version_arr = match arr.get(1).unwrap().clone() {
Value::Array(arr) => arr,
_ => return Err(ParseError::NotWellFormed(format!("Header version field is not of type array")))
};
if arr.len() < 2 {
return Err(ParseError::NotWellFormed(format!("Header messagepack array to short. ({}<2)", arr.len())));
}

if version_arr.len() != 2 {
return Err(ParseError::NotWellFormed("Header version field is not of type array[2]".to_string()));
}
// 4 Sanity check the format name, version, and mode.
// 4.1 check first array element to be the string "saltpack"
let saltpack_str = match arr.get(0).unwrap().clone() {
Value::String(e) => e,
_ => return Err(ParseError::NotWellFormed("First header array element is not of type string.".to_string()))
};

let version_major = match version_arr.get(0).unwrap().clone() {
Value::Integer(Integer::U64(i)) => i,
_ => return Err(ParseError::NotWellFormed(format!("Header version field[0] is not of type integer"))),
};
if saltpack_str != "saltpack" {
return Err(ParseError::NotWellFormed(format!("Header magic string should be 'saltpack' but is {}", saltpack_str)));
}

let version_minor = match version_arr.get(1).unwrap().clone() {
Value::Integer(Integer::U64(i)) => i,
_ => return Err(ParseError::NotWellFormed(format!("Header version field[1] is not of type integer"))),
};
// 4.2.1 check second array element to be version number
let version_arr = match arr.get(1).unwrap().clone() {
Value::Array(arr) => arr,
_ => return Err(ParseError::NotWellFormed(format!("Header version field is not of type array")))
};

if version_major != 1 || version_minor != 0 {
return Err(ParseError::WrongSaltpackVersion(format!("Saltpack version {}.{} found. This is the decoder for Version 1.0", version_major, version_minor), version_major, version_minor));
}
if version_arr.len() != 2 {
return Err(ParseError::NotWellFormed("Header version field is not of type array[2]".to_string()));
}

if arr.len() < 5 {
return Err(ParseError::NotWellFormed(format!("Header messagepack array to short. ({}<5)", arr.len())));
}
let version_major = match version_arr.get(0).unwrap().clone() {
Value::Integer(Integer::U64(i)) => i,
_ => return Err(ParseError::NotWellFormed(format!("Header version field[0] is not of type integer"))),
};

let version_minor = match version_arr.get(1).unwrap().clone() {
Value::Integer(Integer::U64(i)) => i,
_ => return Err(ParseError::NotWellFormed(format!("Header version field[1] is not of type integer"))),
};

let mode = match arr.get(2).unwrap().clone() {
Value::Integer(Integer::U64(i)) if i == 0 => SaltpackMessageType::ENCRYPTEDMESSAGE,
Value::Integer(Integer::U64(i)) if i == 1 => SaltpackMessageType::SIGNEDMESSAGE,
Value::Integer(Integer::U64(i)) if i == 2 => SaltpackMessageType::DETACHEDSIGNATURE,
Value::Integer(Integer::U64(i)) => return Err(ParseError::UnknownMode(format!("Unknown saltpack mode. {}", i), i)),
_ => return Err(ParseError::NotWellFormed(format!("Header mode field[2] is not of type integer")))
};
// 4.2.2 check version number to be [1 0]
if version_major != 1 || version_minor != 0 {
return Err(ParseError::WrongSaltpackVersion(format!("Saltpack version {}.{} found. This is the decoder for Version 1.0", version_major, version_minor), version_major, version_minor));
}

// We got the correct version, so we can assume more header fields
if arr.len() < 5 {
return Err(ParseError::NotWellFormed(format!("Header messagepack array to short. ({}<5)", arr.len())));
}

// 4.2.3 Check mode
let mode = match arr.get(2).unwrap().clone() {
Value::Integer(Integer::U64(i)) if i == 0 => SaltpackMessageType::ENCRYPTEDMESSAGE,
Value::Integer(Integer::U64(i)) if i == 1 => SaltpackMessageType::SIGNEDMESSAGE,
Value::Integer(Integer::U64(i)) if i == 2 => SaltpackMessageType::DETACHEDSIGNATURE,
Value::Integer(Integer::U64(i)) => return Err(ParseError::UnknownMode(format!("Unknown saltpack mode. {}", i), i)),
_ => return Err(ParseError::NotWellFormed(format!("Header mode field[2] is not of type integer")))
};

let eph_pub = match arr.get(3).unwrap().clone() {
Value::Binary(bin) => bin,
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