//! A small ASN.1 parsing library for Rust. In particular, this library is used
//! to translate the binary DER encoding of an ASN.1-formatted document into the
//! core primitives of ASN.1. It is assumed that you can do what you need to
//! from there.
//!
//! The critical items for this document are the traits `ToASN1` and `FromASN1`.
//! The first takes your data type and encodes it into a `Vec` of simple ASN.1
//! structures (`ASN1Block`s). The latter inverts the process.
//!
//! Items that implement `ToASN1` can be used with the function `der_encode`
//! to provide single-step encoding of a data type to binary DER encoding.
//! Similarly, items that are `FromASN` can be single-step decoded using
//! the helper function `der_decode`.
//!
//! You can implement one or both traits, depending on your needs. If you do
//! implement both, the obvious encode/decode quickcheck property is strongly
//! advised.
//!
//! For decoding schemes that require the actual bytes associated with the
//! binary representation, we also provide `FromASN1WithBody`. This can be
//! used with the offset information in the primitive `ASN1Block`s to, for
//! example, validate signatures in X509 documents.
//!
//! Finally, this library supports ASN.1 class information. I'm still not sure
//! why it's useful, but there it is.
//!
//! Please send any bug reports, patches, and curses to the GitHub repository
//! at https://github.com/acw/simple_asn1.
extern crate chrono;
extern crate num;
#[cfg(test)]
#[macro_use]
extern crate quickcheck;
#[cfg(test)]
extern crate rand;
use chrono::{DateTime,TimeZone,Utc};
use num::{BigInt,BigUint,FromPrimitive,One,ToPrimitive,Zero};
use std::error::Error;
use std::fmt;
use std::iter::FromIterator;
use std::mem::size_of;
/// An ASN.1 block class.
///
/// I'm not sure if/when these are used, but here they are in case you want
/// to do something with them.
#[derive(Clone,Copy,Debug,PartialEq)]
pub enum ASN1Class { Universal, Application, ContextSpecific, Private }
/// A primitive block from ASN.1.
///
/// Primitive blocks all contain the class of the block and the offset from
/// the beginning of the parsed document, followed by whatever data is
/// associated with the block. The latter should be fairly self-explanatory,
/// so let's discuss the offset.
///
/// The offset is only valid during the reading process. It is ignored for
/// the purposes of encoding blocks into their binary form. It is also
/// ignored for the purpose of comparisons via `==`. It is included entirely
/// to support the parsing of things like X509 certificates, in which it is
/// necessary to know when particular blocks end.
#[derive(Clone,Debug)]
pub enum ASN1Block {
Boolean(ASN1Class, usize, bool),
Integer(ASN1Class, usize, BigInt),
BitString(ASN1Class, usize, usize, Vec),
OctetString(ASN1Class, usize, Vec),
Null(ASN1Class, usize),
ObjectIdentifier(ASN1Class, usize, OID),
UTF8String(ASN1Class, usize, String),
PrintableString(ASN1Class, usize, String),
TeletexString(ASN1Class, usize, String),
IA5String(ASN1Class, usize, String),
UTCTime(ASN1Class, usize, DateTime),
GeneralizedTime(ASN1Class, usize, DateTime),
UniversalString(ASN1Class, usize, String),
BMPString(ASN1Class, usize, String),
Sequence(ASN1Class, usize, Vec),
Set(ASN1Class, usize, Vec),
Unknown(ASN1Class, usize, BigUint, Vec)
}
impl ASN1Block {
/// Get the class associated with the given ASN1Block, regardless of what
/// kind of block it is.
pub fn class(&self) -> ASN1Class {
match self {
&ASN1Block::Boolean(c,_,_) => c,
&ASN1Block::Integer(c,_,_) => c,
&ASN1Block::BitString(c,_,_,_) => c,
&ASN1Block::OctetString(c,_,_) => c,
&ASN1Block::Null(c,_) => c,
&ASN1Block::ObjectIdentifier(c,_,_) => c,
&ASN1Block::UTF8String(c,_,_) => c,
&ASN1Block::PrintableString(c,_,_) => c,
&ASN1Block::TeletexString(c,_,_) => c,
&ASN1Block::IA5String(c,_,_) => c,
&ASN1Block::UTCTime(c,_,_) => c,
&ASN1Block::GeneralizedTime(c,_,_) => c,
&ASN1Block::UniversalString(c,_,_) => c,
&ASN1Block::BMPString(c,_,_) => c,
&ASN1Block::Sequence(c,_,_) => c,
&ASN1Block::Set(c,_,_) => c,
&ASN1Block::Unknown(c,_,_,_) => c
}
}
/// Get the starting offset associated with the given ASN1Block, regardless
/// of what kind of block it is.
pub fn offset(&self) -> usize {
match self {
&ASN1Block::Boolean(_,o,_) => o,
&ASN1Block::Integer(_,o,_) => o,
&ASN1Block::BitString(_,o,_,_) => o,
&ASN1Block::OctetString(_,o,_) => o,
&ASN1Block::Null(_,o) => o,
&ASN1Block::ObjectIdentifier(_,o,_) => o,
&ASN1Block::UTF8String(_,o,_) => o,
&ASN1Block::PrintableString(_,o,_) => o,
&ASN1Block::TeletexString(_,o,_) => o,
&ASN1Block::IA5String(_,o,_) => o,
&ASN1Block::UTCTime(_,o,_) => o,
&ASN1Block::GeneralizedTime(_,o,_) => o,
&ASN1Block::UniversalString(_,o,_) => o,
&ASN1Block::BMPString(_,o,_) => o,
&ASN1Block::Sequence(_,o,_) => o,
&ASN1Block::Set(_,o,_) => o,
&ASN1Block::Unknown(_,o,_,_) => o
}
}
}
impl PartialEq for ASN1Block {
fn eq(&self, other: &ASN1Block) -> bool {
match (self, other) {
(&ASN1Block::Boolean(a1,_,b1),
&ASN1Block::Boolean(a2,_,b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::Integer(a1,_,ref b1),
&ASN1Block::Integer(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::BitString(a1,_,b1,ref c1),
&ASN1Block::BitString(a2,_,b2,ref c2)) =>
(a1 == a2) && (b1 == b2) && (c1 == c2),
(&ASN1Block::OctetString(a1,_,ref b1),
&ASN1Block::OctetString(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::Null(a1,_),
&ASN1Block::Null(a2,_)) =>
(a1 == a2),
(&ASN1Block::ObjectIdentifier(a1,_,ref b1),
&ASN1Block::ObjectIdentifier(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::UTF8String(a1,_,ref b1),
&ASN1Block::UTF8String(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::PrintableString(a1,_,ref b1),
&ASN1Block::PrintableString(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::TeletexString(a1,_,ref b1),
&ASN1Block::TeletexString(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::IA5String(a1,_,ref b1),
&ASN1Block::IA5String(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::UTCTime(a1,_,ref b1),
&ASN1Block::UTCTime(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::GeneralizedTime(a1,_,ref b1),
&ASN1Block::GeneralizedTime(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::UniversalString(a1,_,ref b1),
&ASN1Block::UniversalString(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::BMPString(a1,_,ref b1),
&ASN1Block::BMPString(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::Sequence(a1,_,ref b1),
&ASN1Block::Sequence(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::Set(a1,_,ref b1),
&ASN1Block::Set(a2,_,ref b2)) =>
(a1 == a2) && (b1 == b2),
(&ASN1Block::Unknown(a1,_,ref b1,ref c1),
&ASN1Block::Unknown(a2,_,ref b2,ref c2)) =>
(a1 == a2) && (b1 == b2) && (c1 == c2),
_ =>
false
}
}
}
/// An ASN.1 OID.
#[derive(Clone,Debug,PartialEq)]
pub struct OID(Vec);
impl OID {
/// Generate an ASN.1. The vector should be in the obvious format,
/// with each component going left-to-right.
pub fn new(x: Vec) -> OID {
OID(x)
}
}
impl<'a> PartialEq for &'a OID {
fn eq(&self, v2: &OID) -> bool {
let &&OID(ref vec1) = self;
let &OID(ref vec2) = v2;
if vec1.len() != vec2.len() {
return false
}
for i in 0..vec1.len() {
if vec1[i] != vec2[i] {
return false;
}
}
true
}
}
/// A handy macro for generating OIDs from a sequence of `u64`s.
///
/// Usage: oid!(1,2,840,113549,1,1,1) creates an OID that matches
/// 1.2.840.113549.1.1.1. (Coincidentally, this is RSA.)
#[macro_export]
macro_rules! oid {
( $( $e: expr ),* ) => {{
let mut res = Vec::new();
$(
res.push(BigUint::from($e as u64));
)*
OID::new(res)
}};
}
const PRINTABLE_CHARS: &'static str =
"ABCDEFGHIJKLMOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()+,-./:=? ";
/// An error that can arise decoding ASN.1 primitive blocks.
#[derive(Clone,Debug,PartialEq)]
pub enum ASN1DecodeErr {
EmptyBuffer,
BadBooleanLength,
LengthTooLarge,
UTF8DecodeFailure,
PrintableStringDecodeFailure,
InvalidDateValue(String)
}
/// An error that can arise encoding ASN.1 primitive blocks.
#[derive(Clone,Debug,PartialEq)]
pub enum ASN1EncodeErr {
ObjectIdentHasTooFewFields,
ObjectIdentVal1TooLarge,
ObjectIdentVal2TooLarge
}
impl fmt::Display for ASN1EncodeErr {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str(self.description())
}
}
impl Error for ASN1EncodeErr {
fn description(&self) -> &str {
match self {
ASN1EncodeErr::ObjectIdentHasTooFewFields =>
"ASN1 object identifier has too few fields.",
ASN1EncodeErr::ObjectIdentVal1TooLarge =>
"First value in ASN1 OID is too big.",
ASN1EncodeErr::ObjectIdentVal2TooLarge =>
"Second value in ASN1 OID is too big."
}
}
fn cause(&self) -> Option<&Error> {
None
}
fn source(&self) -> Option<&(Error + 'static)> {
None
}
}
/// Translate a binary blob into a series of `ASN1Block`s, or provide an
/// error if it didn't work.
pub fn from_der(i: &[u8]) -> Result,ASN1DecodeErr> {
from_der_(i, 0)
}
fn from_der_(i: &[u8], start_offset: usize)
-> Result,ASN1DecodeErr>
{
let mut result: Vec = Vec::new();
let mut index: usize = 0;
let len = i.len();
while index < len {
let soff = start_offset + index;
let (tag, class) = decode_tag(i, &mut index);
let len = decode_length(i, &mut index)?;
let body = &i[index .. (index + len)];
match tag.to_u8() {
// BOOLEAN
Some(0x01) => {
if len != 1 {
return Err(ASN1DecodeErr::BadBooleanLength);
}
result.push(ASN1Block::Boolean(class, soff, body[0] != 0));
}
// INTEGER
Some(0x02) => {
let res = BigInt::from_signed_bytes_be(&body);
result.push(ASN1Block::Integer(class, soff, res));
}
// BIT STRING
Some(0x03) if body.len() == 0 => {
result.push(ASN1Block::BitString(class, soff, 0, Vec::new()))
}
Some(0x03) => {
let bits = (&body[1..]).to_vec();
let nbits = (bits.len() * 8) - (body[0] as usize);
result.push(ASN1Block::BitString(class, soff, nbits, bits))
}
// OCTET STRING
Some(0x04) => {
result.push(ASN1Block::OctetString(class, soff, body.to_vec()))
}
// NULL
Some(0x05) => {
result.push(ASN1Block::Null(class, soff));
}
// OBJECT IDENTIFIER
Some(0x06) => {
let mut value1 = BigUint::zero();
let mut value2 = BigUint::from_u8(body[0]).unwrap();
let mut oidres = Vec::new();
let mut bindex = 1;
if body[0] >= 40 {
if body[0] < 80 {
value1 = BigUint::one();
value2 = value2 - BigUint::from_u8(40).unwrap();
} else {
value1 = BigUint::from_u8(2).unwrap();
value2 = value2 - BigUint::from_u8(80).unwrap();
}
}
oidres.push(value1);
oidres.push(value2);
while bindex < body.len() {
oidres.push(decode_base127(body, &mut bindex));
}
let res = OID(oidres);
result.push(ASN1Block::ObjectIdentifier(class, soff, res))
}
// UTF8STRING
Some(0x0C) => {
match String::from_utf8(body.to_vec()) {
Ok(v) =>
result.push(ASN1Block::UTF8String(class, soff, v)),
Err(_) =>
return Err(ASN1DecodeErr::UTF8DecodeFailure)
}
}
// SEQUENCE
Some(0x10) => {
match from_der_(body, start_offset + index) {
Ok(items) =>
result.push(ASN1Block::Sequence(class, soff, items)),
Err(e) =>
return Err(e)
}
}
// SET
Some(0x11) => {
match from_der_(body, start_offset + index) {
Ok(items) =>
result.push(ASN1Block::Set(class, soff, items)),
Err(e) =>
return Err(e)
}
}
// PRINTABLE STRING
Some(0x13) => {
let mut res = String::new();
let mut val = body.iter().map(|x| *x as char);
for c in val {
if PRINTABLE_CHARS.contains(c) {
res.push(c);
} else {
return Err(ASN1DecodeErr::PrintableStringDecodeFailure);
}
}
result.push(ASN1Block::PrintableString(class, soff, res));
}
// TELETEX STRINGS
Some(0x14) => {
match String::from_utf8(body.to_vec()) {
Ok(v) =>
result.push(ASN1Block::TeletexString(class, soff, v)),
Err(_) =>
return Err(ASN1DecodeErr::UTF8DecodeFailure)
}
}
// IA5 (ASCII) STRING
Some(0x16) => {
let val = body.iter().map(|x| *x as char);
let res = String::from_iter(val);
result.push(ASN1Block::IA5String(class, soff, res))
}
// UTCTime
Some(0x17) => {
if body.len() != 13 {
return Err(ASN1DecodeErr::InvalidDateValue(format!("{}",body.len())));
}
let v = String::from_iter(body.iter().map(|x| *x as char));
match Utc.datetime_from_str(&v, "%y%m%d%H%M%SZ") {
Err(_) =>
return Err(ASN1DecodeErr::InvalidDateValue(v)),
Ok(t) => {
result.push(ASN1Block::UTCTime(class, soff, t))
}
}
}
// GeneralizedTime
Some(0x18) => {
if body.len() < 15 {
return Err(ASN1DecodeErr::InvalidDateValue(format!("{}",body.len())));
}
let mut v = String::from_iter(body.iter().map(|x| *x as char));
// We need to add padding back to the string if it's not there.
if v.find('.').is_none() {
v.insert(15, '.')
}
while v.len() < 25 {
let idx = v.len() - 1;
v.insert(idx, '0');
}
match Utc.datetime_from_str(&v, "%Y%m%d%H%M%S.%fZ") {
Err(_) =>
return Err(ASN1DecodeErr::InvalidDateValue(v)),
Ok(t) => {
result.push(ASN1Block::GeneralizedTime(class, soff, t))
}
}
}
// UNIVERSAL STRINGS
Some(0x1C) => {
match String::from_utf8(body.to_vec()) {
Ok(v) =>
result.push(ASN1Block::UniversalString(class, soff, v)),
Err(_) =>
return Err(ASN1DecodeErr::UTF8DecodeFailure)
}
}
// UNIVERSAL STRINGS
Some(0x1E) => {
match String::from_utf8(body.to_vec()) {
Ok(v) =>
result.push(ASN1Block::BMPString(class, soff, v)),
Err(_) =>
return Err(ASN1DecodeErr::UTF8DecodeFailure)
}
}
// Dunno.
_ => {
result.push(ASN1Block::Unknown(class, soff, tag, body.to_vec()));
}
}
index += len;
}
if result.is_empty() {
Err(ASN1DecodeErr::EmptyBuffer)
} else {
Ok(result)
}
}
fn decode_tag(i: &[u8], index: &mut usize) -> (BigUint, ASN1Class) {
let tagbyte = i[*index];
let class = decode_class(tagbyte);
let basetag = tagbyte & 0b11111;
*index += 1;
if basetag == 0b11111 {
let res = decode_base127(i, index);
(res, class)
} else {
(BigUint::from(basetag), class)
}
}
fn decode_base127(i: &[u8], index: &mut usize) -> BigUint {
let mut res = BigUint::zero();
loop {
let nextbyte = i[*index];
*index += 1;
res = (res << 7) + BigUint::from(nextbyte & 0x7f);
if (nextbyte & 0x80) == 0 {
return res;
}
}
}
fn decode_class(i: u8) -> ASN1Class {
match i >> 6 {
0b00 => ASN1Class::Universal,
0b01 => ASN1Class::Application,
0b10 => ASN1Class::ContextSpecific,
0b11 => ASN1Class::Private,
_ => panic!("The universe is broken.")
}
}
fn decode_length(i: &[u8], index: &mut usize) -> Result {
let startbyte = i[*index];
// NOTE: Technically, this size can be much larger than a usize.
// However, our whole universe starts to break down if we get
// things that big. So we're boring, and only accept lengths
// that fit within a usize.
*index += 1;
if startbyte >= 0x80 {
let mut lenlen = (startbyte & 0x7f) as usize;
let mut res = 0;
if lenlen > size_of::() {
return Err(ASN1DecodeErr::LengthTooLarge);
}
while lenlen > 0 {
res = (res << 8) + (i[*index] as usize);
*index += 1;
lenlen -= 1;
}
Ok(res)
} else {
Ok(startbyte as usize)
}
}
/// Given an `ASN1Block`, covert it to its DER encoding, or return an error
/// if something broke along the way.
pub fn to_der(i: &ASN1Block) -> Result,ASN1EncodeErr> {
match i {
// BOOLEAN
&ASN1Block::Boolean(cl, _, val) => {
let inttag = BigUint::one();
let mut tagbytes = encode_tag(cl, &inttag);
tagbytes.push(1);
tagbytes.push(if val { 0xFF } else { 0x00 });
Ok(tagbytes)
}
// INTEGER
&ASN1Block::Integer(cl, _, ref int) => {
let mut base = int.to_signed_bytes_be();
let mut lenbytes = encode_len(base.len());
let inttag = BigUint::from_u8(0x02).unwrap();
let mut tagbytes = encode_tag(cl, &inttag);
let mut result = Vec::new();
result.append(&mut tagbytes);
result.append(&mut lenbytes);
result.append(&mut base);
Ok(result)
}
// BIT STRING
&ASN1Block::BitString(cl, _, bits, ref vs) => {
let inttag = BigUint::from_u8(0x03).unwrap();
let mut tagbytes = encode_tag(cl, &inttag);
if bits == 0 {
tagbytes.push(0);
Ok(tagbytes)
} else {
let mut lenbytes = encode_len(vs.len() + 1);
let nbits = (vs.len() * 8) - bits;
let mut result = Vec::new();
result.append(&mut tagbytes);
result.append(&mut lenbytes);
result.push(nbits as u8);
result.extend(vs.iter());
Ok(result)
}
}
// OCTET STRING
&ASN1Block::OctetString(cl, _, ref bytes) => {
let inttag = BigUint::from_u8(0x04).unwrap();
let mut tagbytes = encode_tag(cl, &inttag);
let mut lenbytes = encode_len(bytes.len());
let mut result = Vec::new();
result.append(&mut tagbytes);
result.append(&mut lenbytes);
result.extend(bytes.iter());
Ok(result)
}
// NULL
&ASN1Block::Null(cl, _) => {
let inttag = BigUint::from_u8(0x05).unwrap();
let mut result = encode_tag(cl, &inttag);
result.push(0);
Ok(result)
}
// OBJECT IDENTIFIER
&ASN1Block::ObjectIdentifier(cl, _, OID(ref nums)) => {
match (nums.get(0), nums.get(1)) {
(Some(v1), Some(v2)) => {
let two = BigUint::from_u8(2).unwrap();
// first, validate that the first two items meet spec
if v1 > &two {
return Err(ASN1EncodeErr::ObjectIdentVal1TooLarge)
}
let u175 = BigUint::from_u8(175).unwrap();
let u39 = BigUint::from_u8(39).unwrap();
let bound = if v1 == &two { u175 } else { u39 };
if v2 > &bound {
return Err(ASN1EncodeErr::ObjectIdentVal2TooLarge);
}
// the following unwraps must be safe, based on the
// validation above.
let value1 = v1.to_u8().unwrap();
let value2 = v2.to_u8().unwrap();
let byte1 = (value1 * 40) + value2;
// now we can build all the rest of the body
let mut body = vec![byte1];
for num in nums.iter().skip(2) {
let mut local = encode_base127(&num);
body.append(&mut local);
}
// now that we have the body, we can build the header
let inttag = BigUint::from_u8(0x06).unwrap();
let mut result = encode_tag(cl, &inttag);
let mut lenbytes = encode_len(body.len());
result.append(&mut lenbytes);
result.append(&mut body);
Ok(result)
}
_ => {
Err(ASN1EncodeErr::ObjectIdentHasTooFewFields)
}
}
}
// SEQUENCE
&ASN1Block::Sequence(cl, _, ref items) => {
let mut body = Vec::new();
// put all the subsequences into a block
for x in items.iter() {
let mut bytes = to_der(x)?;
body.append(&mut bytes);
}
let inttag = BigUint::from_u8(0x10).unwrap();
let mut lenbytes = encode_len(body.len());
let mut tagbytes = encode_tag(cl, &inttag);
let mut res = Vec::new();
res.append(&mut tagbytes);
res.append(&mut lenbytes);
res.append(&mut body);
Ok(res)
}
// SET
&ASN1Block::Set(cl, _, ref items) => {
let mut body = Vec::new();
// put all the subsequences into a block
for x in items.iter() {
let mut bytes = to_der(x)?;
body.append(&mut bytes);
}
let inttag = BigUint::from_u8(0x11).unwrap();
let mut lenbytes = encode_len(body.len());
let mut tagbytes = encode_tag(cl, &inttag);
let mut res = Vec::new();
res.append(&mut tagbytes);
res.append(&mut lenbytes);
res.append(&mut body);
Ok(res)
}
&ASN1Block::UTCTime(cl, _, ref time) => {
let mut body = time.format("%y%m%d%H%M%SZ").to_string().into_bytes();
let inttag = BigUint::from_u8(0x17).unwrap();
let mut lenbytes = encode_len(body.len());
let mut tagbytes = encode_tag(cl, &inttag);
let mut res = Vec::new();
res.append(&mut tagbytes);
res.append(&mut lenbytes);
res.append(&mut body);
Ok(res)
}
&ASN1Block::GeneralizedTime(cl, _, ref time) => {
let base = time.format("%Y%m%d%H%M%S.%f").to_string();
let zclear = base.trim_right_matches('0');
let dclear = zclear.trim_right_matches('.');
let mut body = format!("{}Z", dclear).into_bytes();
let inttag = BigUint::from_u8(0x18).unwrap();
let mut lenbytes = encode_len(body.len());
let mut tagbytes = encode_tag(cl, &inttag);
let mut res = Vec::new();
res.append(&mut tagbytes);
res.append(&mut lenbytes);
res.append(&mut body);
Ok(res)
}
&ASN1Block::UTF8String(cl, _, ref str) =>
encode_asn1_string(0x0c, false, cl, str),
&ASN1Block::PrintableString(cl, _, ref str) =>
encode_asn1_string(0x13, true, cl, str),
&ASN1Block::TeletexString(cl, _, ref str) =>
encode_asn1_string(0x14, false, cl, str),
&ASN1Block::UniversalString(cl, _, ref str) =>
encode_asn1_string(0x1c, false, cl, str),
&ASN1Block::IA5String(cl, _, ref str) =>
encode_asn1_string(0x16, true, cl, str),
&ASN1Block::BMPString(cl, _, ref str) =>
encode_asn1_string(0x1e, false, cl, str),
// Unknown blocks
&ASN1Block::Unknown(class, _, ref tag, ref bytes) => {
let mut tagbytes = encode_tag(class, &tag);
let mut lenbytes = encode_len(bytes.len());
let mut res = Vec::new();
res.append(&mut tagbytes);
res.append(&mut lenbytes);
res.extend(bytes.iter());
Ok(res)
}
}
}
fn encode_asn1_string(tag: u8, force_chars: bool, c: ASN1Class, s: &String)
-> Result,ASN1EncodeErr>
{
let mut body = { if force_chars {
let mut out = Vec::new();
for c in s.chars() {
out.push(c as u8);
}
out
} else {
s.clone().into_bytes()
} };
let inttag = BigUint::from_u8(tag).unwrap();
let mut lenbytes = encode_len(body.len());
let mut tagbytes = encode_tag(c, &inttag);
let mut res = Vec::new();
res.append(&mut tagbytes);
res.append(&mut lenbytes);
res.append(&mut body);
Ok(res)
}
fn encode_tag(c: ASN1Class, t: &BigUint) -> Vec {
let cbyte = encode_class(c);
match t.to_u8() {
Some(x) if x < 31 => {
vec![cbyte | x]
}
_ => {
let mut res = encode_base127(t);
res.insert(0, cbyte | 0b00011111);
res
}
}
}
fn encode_base127(v: &BigUint) -> Vec {
let mut acc = v.clone();
let mut res = Vec::new();
let u128 = BigUint::from_u8(128).unwrap();
let zero = BigUint::zero();
while acc > zero {
// we build this vector backwards
let digit = &acc % &u128;
acc = acc >> 7;
match digit.to_u8() {
None =>
panic!("7 bits don't fit into 8, cause ..."),
Some(x) if res.is_empty() =>
res.push(x),
Some(x) =>
res.push(x | 0x80)
}
}
res.reverse();
res
}
fn encode_class(c: ASN1Class) -> u8 {
match c {
ASN1Class::Universal => 0b00000000,
ASN1Class::Application => 0b01000000,
ASN1Class::ContextSpecific => 0b10000000,
ASN1Class::Private => 0b11000000,
}
}
fn encode_len(x: usize) -> Vec {
if x < 128 {
vec![x as u8]
} else {
let mut bstr = Vec::new();
let mut work = x;
// convert this into bytes, backwards
while work > 0 {
bstr.push(work as u8);
work = work >> 8;
}
// encode the front of the length
let len = bstr.len() as u8;
bstr.push(len | 0x80);
// and then reverse it into the right order
bstr.reverse();
bstr
}
}
// ----------------------------------------------------------------------------
/// A trait defining types that can be decoded from an `ASN1Block` stream,
/// assuming they also have access to the underlying bytes making up the
/// stream.
pub trait FromASN1WithBody : Sized {
type Error : From;
fn from_asn1_with_body<'a>(v: &'a[ASN1Block], _b: &[u8])
-> Result<(Self,&'a[ASN1Block]),Self::Error>;
}
/// A trait defining types that can be decoded from an `ASN1Block` stream.
/// Any member of this trait is also automatically a member of
/// `FromASN1WithBody`, as it can obviously just ignore the body.
pub trait FromASN1 : Sized {
type Error : From;
fn from_asn1(v: &[ASN1Block])
-> Result<(Self,&[ASN1Block]),Self::Error>;
}
impl FromASN1WithBody for T {
type Error = T::Error;
fn from_asn1_with_body<'a>(v: &'a[ASN1Block], _b: &[u8])
-> Result<(T,&'a[ASN1Block]),T::Error>
{
T::from_asn1(v)
}
}
/// Automatically decode a type via DER encoding, assuming that the type
/// is a member of `FromASN1` or `FromASN1WithBody`.
pub fn der_decode(v: &[u8]) -> Result
{
let vs = from_der(v)?;
T::from_asn1_with_body(&vs, v).and_then(|(a,_)| Ok(a))
}
/// The set of types that can automatically converted into a sequence
/// of `ASN1Block`s. You should probably use to_asn1() but implement
/// to_asn1_class(). The former has a default implementation that passes
/// `ASN1Class::Universal` as the tag to use, which should be good for
/// most people.
pub trait ToASN1 {
type Error : From;
fn to_asn1(&self) -> Result,Self::Error> {
self.to_asn1_class(ASN1Class::Universal)
}
fn to_asn1_class(&self, c: ASN1Class)
-> Result,Self::Error>;
}
/// Automatically encode a type into binary via DER encoding, assuming
/// that the type is a member of `ToASN1`.
pub fn der_encode(v: &T) -> Result,T::Error>
{
let blocks = T::to_asn1(&v)?;
let mut res = Vec::new();
for block in blocks {
let mut x = to_der(&block)?;
res.append(&mut x);
}
Ok(res)
}
// ----------------------------------------------------------------------------
#[cfg(test)]
mod tests {
use chrono::offset::LocalResult;
use quickcheck::{Arbitrary,Gen};
use std::fs::File;
use std::io::Read;
use rand::{Rng, distributions::Standard};
use super::*;
impl Arbitrary for ASN1Class {
fn arbitrary(g: &mut G) -> ASN1Class {
match g.gen::() % 4 {
0 => ASN1Class::Private,
1 => ASN1Class::ContextSpecific,
2 => ASN1Class::Universal,
3 => ASN1Class::Application,
_ => panic!("I weep for a broken life.")
}
}
}
quickcheck! {
fn class_encdec_roundtrips(c: ASN1Class) -> bool {
c == decode_class(encode_class(c.clone()))
}
fn class_decenc_roundtrips(v: u8) -> bool {
(v & 0b11000000) == encode_class(decode_class(v))
}
}
#[derive(Clone,Debug)]
struct RandomUint {
x: BigUint
}
impl Arbitrary for RandomUint {
fn arbitrary(g: &mut G) -> RandomUint {
let v = BigUint::from_u32(g.gen::()).unwrap();
RandomUint{ x: v }
}
}
quickcheck! {
fn tags_encdec_roundtrips(c: ASN1Class, t: RandomUint) -> bool {
let bytes = encode_tag(c, &t.x);
let mut zero = 0;
let (t2, c2) = decode_tag(&bytes[..], &mut zero);
(c == c2) && (t.x == t2)
}
fn len_encdec_roundtrips(l: usize) -> bool {
let bytes = encode_len(l);
let mut zero = 0;
match decode_length(&bytes[..], &mut zero) {
Err(_) => false,
Ok(l2) => l == l2
}
}
}
#[derive(Clone,Debug)]
struct RandomInt {
x: BigInt
}
impl Arbitrary for RandomInt {
fn arbitrary(g: &mut G) -> RandomInt {
let v = BigInt::from_i64(g.gen::()).unwrap();
RandomInt{ x: v }
}
}
#[allow(type_alias_bounds)]
type ASN1BlockGen = fn(&mut G, usize) -> ASN1Block;
fn arb_boolean(g: &mut G, _d: usize) -> ASN1Block {
let c = ASN1Class::arbitrary(g);
let v = g.gen::();
ASN1Block::Boolean(c, 0, v)
}
fn arb_integer(g: &mut G, _d: usize) -> ASN1Block {
let c = ASN1Class::arbitrary(g);
let d = RandomInt::arbitrary(g);
ASN1Block::Integer(c, 0, d.x)
}
fn arb_bitstr(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let size = g.gen::() as usize % 16;
let maxbits = (size as usize) * 8;
let modbits = g.gen::() as usize % 8;
let nbits = if modbits > maxbits
{ maxbits }
else { maxbits - modbits };
let bytes = g.sample_iter::(&Standard).take(size).collect();
ASN1Block::BitString(class, 0, nbits, bytes)
}
fn arb_octstr(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let size = g.gen::() as usize % 16;
let bytes = g.sample_iter::(&Standard).take(size).collect();
ASN1Block::OctetString(class, 0, bytes)
}
fn arb_null(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
ASN1Block::Null(class, 0)
}
impl Arbitrary for OID {
fn arbitrary(g: &mut G) -> OID {
let count = g.gen_range::(0, 40);
let val1 = g.gen::() % 3;
let v2mod = if val1 == 2 { 176 } else { 40 };
let val2 = g.gen::() % v2mod;
let v1 = BigUint::from_u8(val1).unwrap();
let v2 = BigUint::from_u8(val2).unwrap();
let mut nums = vec![v1, v2];
for _ in 0..count {
let num = RandomUint::arbitrary(g);
nums.push(num.x);
}
OID(nums)
}
}
fn arb_objid(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let oid = OID::arbitrary(g);
ASN1Block::ObjectIdentifier(class, 0, oid)
}
fn arb_seq(g: &mut G, d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let count = g.gen_range::(1, 64);
let mut items = Vec::new();
for _ in 0..count {
items.push(limited_arbitrary(g, d - 1));
}
ASN1Block::Sequence(class, 0, items)
}
fn arb_set(g: &mut G, d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let count = g.gen_range::(1, 64);
let mut items = Vec::new();
for _ in 0..count {
items.push(limited_arbitrary(g, d - 1));
}
ASN1Block::Set(class, 0, items)
}
fn arb_print(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let count = g.gen_range::(0, 384);
let mut items = Vec::new();
for _ in 0..count {
let v = g.choose(PRINTABLE_CHARS.as_bytes()).unwrap();
items.push(*v as char);
}
ASN1Block::PrintableString(class, 0, String::from_iter(items.iter()))
}
fn arb_ia5(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let count = g.gen_range::(0, 384);
let mut items = Vec::new();
for _ in 0..count {
items.push(g.gen::() as char);
}
ASN1Block::IA5String(class, 0, String::from_iter(items.iter()))
}
fn arb_utf8(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let val = String::arbitrary(g);
ASN1Block::UTF8String(class, 0, val)
}
fn arb_tele(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let val = String::arbitrary(g);
ASN1Block::TeletexString(class, 0, val)
}
fn arb_uni(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let val = String::arbitrary(g);
ASN1Block::UniversalString(class, 0, val)
}
fn arb_bmp(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let val = String::arbitrary(g);
ASN1Block::BMPString(class, 0, val)
}
fn arb_utc(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
loop {
let y = g.gen_range::(1970,2069);
let m = g.gen_range::(1,13);
let d = g.gen_range::(1,32);
match Utc.ymd_opt(y,m,d) {
LocalResult::None => {}
LocalResult::Single(d) => {
let h = g.gen_range::(0,24);
let m = g.gen_range::(0,60);
let s = g.gen_range::(0,60);
let t = d.and_hms(h,m,s);
return ASN1Block::UTCTime(class, 0, t);
}
LocalResult::Ambiguous(_,_) => {}
}
}
}
fn arb_time(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
loop {
let y = g.gen_range::(0,10000);
let m = g.gen_range::(1,13);
let d = g.gen_range::(1,32);
match Utc.ymd_opt(y,m,d) {
LocalResult::None => {}
LocalResult::Single(d) => {
let h = g.gen_range::(0,24);
let m = g.gen_range::(0,60);
let s = g.gen_range::(0,60);
let n = g.gen_range::(0,1000000000);
let t = d.and_hms_nano(h,m,s,n);
return ASN1Block::GeneralizedTime(class, 0, t);
}
LocalResult::Ambiguous(_,_) => {}
}
}
}
fn arb_unknown(g: &mut G, _d: usize) -> ASN1Block {
let class = ASN1Class::arbitrary(g);
let tag = RandomUint::arbitrary(g);
let size = g.gen_range::(0, 128);
let items = g.sample_iter::(&Standard).take(size).collect();
ASN1Block::Unknown(class, 0, tag.x, items)
}
fn limited_arbitrary(g: &mut G, d: usize) -> ASN1Block {
let mut possibles: Vec> =
vec![arb_boolean,
arb_integer,
arb_bitstr,
arb_octstr,
arb_null,
arb_objid,
arb_utf8,
arb_print,
arb_tele,
arb_uni,
arb_ia5,
arb_utc,
arb_time,
arb_bmp,
arb_unknown];
if d > 0 {
possibles.push(arb_seq);
possibles.push(arb_set);
}
match g.choose(&possibles[..]) {
Some(f) => f(g, d),
None => panic!("Couldn't generate arbitrary value.")
}
}
impl Arbitrary for ASN1Block {
fn arbitrary(g: &mut G) -> ASN1Block {
limited_arbitrary(g, 2)
}
}
quickcheck! {
fn encode_decode_roundtrips(v: ASN1Block) -> bool {
match to_der(&v) {
Err(e) => {
println!("Serialization error: {:?}", e);
false
}
Ok(bytes) =>
match from_der(&bytes[..]) {
Err(e) => {
println!("Parse error: {:?}", e);
false
}
Ok(ref rvec) if rvec.len() == 1 => {
let v2 = rvec.get(0).unwrap();
if &v != v2 {
println!("Original: {:?}", v);
println!("Constructed: {:?}", v2);
}
&v == v2
}
Ok(_) => {
println!("Too many results returned.");
false
}
}
}
}
}
fn result_int(v: i16) -> Result,ASN1DecodeErr> {
let val = BigInt::from(v);
Ok(vec![ASN1Block::Integer(ASN1Class::Universal, 0, val)])
}
#[test]
fn generalized_time_tests() {
check_spec(&Utc.ymd(1992, 5, 21).and_hms(0,0,0),
"19920521000000Z".to_string());
check_spec(&Utc.ymd(1992, 6, 22).and_hms(12,34,21),
"19920622123421Z".to_string());
check_spec(&Utc.ymd(1992, 7, 22).and_hms_milli(13,21,00,300),
"19920722132100.3Z".to_string());
}
fn check_spec(d: &DateTime, s: String) {
let b = ASN1Block::GeneralizedTime(ASN1Class::Universal, 0, d.clone());
match to_der(&b) {
Err(_) => assert_eq!(format!("Broken: {}", d), s),
Ok(ref vec) => {
let mut resvec = vec.clone();
resvec.remove(0);
resvec.remove(0);
assert_eq!(String::from_utf8(resvec).unwrap(), s);
}
}
}
#[test]
fn base_integer_tests() {
assert_eq!(from_der(&vec![0x02,0x01,0x00]), result_int(0));
assert_eq!(from_der(&vec![0x02,0x01,0x7F]), result_int(127));
assert_eq!(from_der(&vec![0x02,0x02,0x00,0x80]), result_int(128));
assert_eq!(from_der(&vec![0x02,0x02,0x01,0x00]), result_int(256));
assert_eq!(from_der(&vec![0x02,0x01,0x80]), result_int(-128));
assert_eq!(from_der(&vec![0x02,0x02,0xFF,0x7F]), result_int(-129));
}
fn can_parse(f: &str) -> Result,ASN1DecodeErr> {
let mut fd = File::open(f).unwrap();
let mut buffer = Vec::new();
let _amt = fd.read_to_end(&mut buffer);
from_der(&buffer[..])
}
#[test]
fn x509_tests() {
assert!(can_parse("test/server.bin").is_ok());
assert!(can_parse("test/key.bin").is_ok());
}
}