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/* -*- Mode: rust; rust-indent-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
use byteorder::{BigEndian, NativeEndian, ReadBytesExt, WriteBytesExt};
use std::convert::TryInto;
use crate::error::{Error, ErrorType};
use crate::error_here;
/// Accessing fields of packed structs is unsafe (it may be undefined behavior if the field isn't
/// aligned). Since we're implementing a PKCS#11 module, we already have to trust the caller not to
/// give us bad data, so normally we would deal with this by adding an unsafe block. If we do that,
/// though, the compiler complains that the unsafe block is unnecessary. Thus, we use this macro to
/// annotate the unsafe block to silence the compiler.
#[macro_export]
macro_rules! unsafe_packed_field_access {
($e:expr) => {{
#[allow(unused_unsafe)]
let tmp = unsafe { $e };
tmp
}};
}
// The following ENCODED_OID_BYTES_* consist of the encoded bytes of an ASN.1
// OBJECT IDENTIFIER specifying the indicated OID (in other words, the full
// tag, length, and value).
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const ENCODED_OID_BYTES_SECP256R1: &[u8] =
&[0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07];
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const ENCODED_OID_BYTES_SECP384R1: &[u8] = &[0x06, 0x05, 0x2b, 0x81, 0x04, 0x00, 0x22];
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const ENCODED_OID_BYTES_SECP521R1: &[u8] = &[0x06, 0x05, 0x2b, 0x81, 0x04, 0x00, 0x23];
// The following OID_BYTES_* consist of the contents of the bytes of an ASN.1
// OBJECT IDENTIFIER specifying the indicated OID (in other words, just the
// value, and not the tag or length).
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const OID_BYTES_SHA_256: &[u8] = &[0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01];
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const OID_BYTES_SHA_384: &[u8] = &[0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02];
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const OID_BYTES_SHA_512: &[u8] = &[0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03];
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub const OID_BYTES_SHA_1: &[u8] = &[0x2b, 0x0e, 0x03, 0x02, 0x1a];
// This is a helper function to take a value and lay it out in memory how
// PKCS#11 is expecting it.
pub fn serialize_uint<T: TryInto<u64>>(value: T) -> Result<Vec<u8>, Error> {
let value_size = std::mem::size_of::<T>();
let mut value_buf = Vec::with_capacity(value_size);
let value_as_u64 = value
.try_into()
.map_err(|_| error_here!(ErrorType::ValueTooLarge))?;
value_buf
.write_uint::<NativeEndian>(value_as_u64, value_size)
.map_err(|_| error_here!(ErrorType::LibraryFailure))?;
Ok(value_buf)
}
/// Given a slice of DER bytes representing an RSA public key, extracts the bytes of the modulus
/// as an unsigned integer. Also verifies that the public exponent is present (again as an
/// unsigned integer). Finally verifies that reading these values consumes the entirety of the
/// slice.
/// RSAPublicKey ::= SEQUENCE {
/// modulus INTEGER, -- n
/// publicExponent INTEGER -- e
/// }
pub fn read_rsa_modulus(public_key: &[u8]) -> Result<Vec<u8>, Error> {
let mut sequence = Sequence::new(public_key)?;
let modulus_value = sequence.read_unsigned_integer()?;
let _exponent = sequence.read_unsigned_integer()?;
if !sequence.at_end() {
return Err(error_here!(ErrorType::ExtraInput));
}
Ok(modulus_value.to_vec())
}
/// Given a slice of DER bytes representing a DigestInfo, extracts the bytes of
/// the OID of the hash algorithm and the digest.
/// DigestInfo ::= SEQUENCE {
/// digestAlgorithm DigestAlgorithmIdentifier,
/// digest Digest }
///
/// DigestAlgorithmIdentifier ::= AlgorithmIdentifier
///
/// AlgorithmIdentifier ::= SEQUENCE {
/// algorithm OBJECT IDENTIFIER,
/// parameters ANY DEFINED BY algorithm OPTIONAL }
///
/// Digest ::= OCTET STRING
pub fn read_digest_info(digest_info: &[u8]) -> Result<(&[u8], &[u8]), Error> {
let mut sequence = Sequence::new(digest_info)?;
let mut algorithm = sequence.read_sequence()?;
let oid = algorithm.read_oid()?;
algorithm.read_null()?;
if !algorithm.at_end() {
return Err(error_here!(ErrorType::ExtraInput));
}
let digest = sequence.read_octet_string()?;
if !sequence.at_end() {
return Err(error_here!(ErrorType::ExtraInput));
}
Ok((oid, digest))
}
/// Given a slice of DER bytes representing an ECDSA signature, extracts the bytes of `r` and `s`
/// as unsigned integers. Also verifies that this consumes the entirety of the slice.
/// Ecdsa-Sig-Value ::= SEQUENCE {
/// r INTEGER,
/// s INTEGER }
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub fn read_ec_sig_point(signature: &[u8]) -> Result<(&[u8], &[u8]), Error> {
let mut sequence = Sequence::new(signature)?;
let r = sequence.read_unsigned_integer()?;
let s = sequence.read_unsigned_integer()?;
if !sequence.at_end() {
return Err(error_here!(ErrorType::ExtraInput));
}
Ok((r, s))
}
/// Given a slice of DER bytes representing an X.509 certificate, extracts the encoded serial
/// number, issuer, and subject. Does not verify that the remainder of the certificate is in any
/// way well-formed.
/// Certificate ::= SEQUENCE {
/// tbsCertificate TBSCertificate,
/// signatureAlgorithm AlgorithmIdentifier,
/// signatureValue BIT STRING }
///
/// TBSCertificate ::= SEQUENCE {
/// version [0] EXPLICIT Version DEFAULT v1,
/// serialNumber CertificateSerialNumber,
/// signature AlgorithmIdentifier,
/// issuer Name,
/// validity Validity,
/// subject Name,
/// ...
///
/// CertificateSerialNumber ::= INTEGER
///
/// Name ::= CHOICE { -- only one possibility for now --
/// rdnSequence RDNSequence }
///
/// RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
///
/// Validity ::= SEQUENCE {
/// notBefore Time,
/// notAfter Time }
#[allow(clippy::type_complexity)]
pub fn read_encoded_certificate_identifiers(
certificate: &[u8],
) -> Result<(Vec<u8>, Vec<u8>, Vec<u8>), Error> {
let mut certificate_sequence = Sequence::new(certificate)?;
let mut tbs_certificate_sequence = certificate_sequence.read_sequence()?;
let _version = tbs_certificate_sequence.read_tagged_value(0)?;
let serial_number = tbs_certificate_sequence.read_encoded_sequence_component(INTEGER)?;
let _signature = tbs_certificate_sequence.read_sequence()?;
let issuer =
tbs_certificate_sequence.read_encoded_sequence_component(SEQUENCE | CONSTRUCTED)?;
let _validity = tbs_certificate_sequence.read_sequence()?;
let subject =
tbs_certificate_sequence.read_encoded_sequence_component(SEQUENCE | CONSTRUCTED)?;
Ok((serial_number, issuer, subject))
}
/// Helper macro for reading some bytes from a slice while checking the slice is long enough.
/// Returns a pair consisting of a slice of the bytes read and a slice of the rest of the bytes
/// from the original slice.
macro_rules! try_read_bytes {
($data:ident, $len:expr) => {{
if $data.len() < $len {
return Err(error_here!(ErrorType::TruncatedInput));
}
$data.split_at($len)
}};
}
/// ASN.1 tag identifying an integer.
const INTEGER: u8 = 0x02;
/// ASN.1 tag identifying an octet string.
const OCTET_STRING: u8 = 0x04;
/// ASN.1 tag identifying a null value.
const NULL: u8 = 0x05;
/// ASN.1 tag identifying an object identifier (OID).
const OBJECT_IDENTIFIER: u8 = 0x06;
/// ASN.1 tag identifying a sequence.
const SEQUENCE: u8 = 0x10;
/// ASN.1 tag modifier identifying an item as constructed.
const CONSTRUCTED: u8 = 0x20;
/// ASN.1 tag modifier identifying an item as context-specific.
const CONTEXT_SPECIFIC: u8 = 0x80;
/// A helper struct for reading items from a DER SEQUENCE (in this case, all sequences are
/// assumed to be CONSTRUCTED).
struct Sequence<'a> {
/// The contents of the SEQUENCE.
contents: Der<'a>,
}
impl<'a> Sequence<'a> {
fn new(input: &'a [u8]) -> Result<Sequence<'a>, Error> {
let mut der = Der::new(input);
let (_, _, sequence_bytes) = der.read_tlv(SEQUENCE | CONSTRUCTED)?;
// We're assuming we want to consume the entire input for now.
if !der.at_end() {
return Err(error_here!(ErrorType::ExtraInput));
}
Ok(Sequence {
contents: Der::new(sequence_bytes),
})
}
// TODO: we're not exhaustively validating this integer
fn read_unsigned_integer(&mut self) -> Result<&'a [u8], Error> {
let (_, _, bytes) = self.contents.read_tlv(INTEGER)?;
if bytes.is_empty() {
return Err(error_here!(ErrorType::InvalidInput));
}
// There may be a leading zero (we should also check that the first bit
// of the rest of the integer is set).
if bytes[0] == 0 && bytes.len() > 1 {
let (_, integer) = bytes.split_at(1);
Ok(integer)
} else {
Ok(bytes)
}
}
fn read_octet_string(&mut self) -> Result<&'a [u8], Error> {
let (_, _, bytes) = self.contents.read_tlv(OCTET_STRING)?;
Ok(bytes)
}
fn read_oid(&mut self) -> Result<&'a [u8], Error> {
let (_, _, bytes) = self.contents.read_tlv(OBJECT_IDENTIFIER)?;
Ok(bytes)
}
fn read_null(&mut self) -> Result<(), Error> {
let (_, _, bytes) = self.contents.read_tlv(NULL)?;
if bytes.is_empty() {
Ok(())
} else {
Err(error_here!(ErrorType::InvalidInput))
}
}
fn read_sequence(&mut self) -> Result<Sequence<'a>, Error> {
let (_, _, sequence_bytes) = self.contents.read_tlv(SEQUENCE | CONSTRUCTED)?;
Ok(Sequence {
contents: Der::new(sequence_bytes),
})
}
fn read_tagged_value(&mut self, tag: u8) -> Result<&'a [u8], Error> {
let (_, _, tagged_value_bytes) = self
.contents
.read_tlv(CONTEXT_SPECIFIC | CONSTRUCTED | tag)?;
Ok(tagged_value_bytes)
}
fn read_encoded_sequence_component(&mut self, tag: u8) -> Result<Vec<u8>, Error> {
let (tag, length, value) = self.contents.read_tlv(tag)?;
let mut encoded_component_bytes = length;
encoded_component_bytes.insert(0, tag);
encoded_component_bytes.extend_from_slice(value);
Ok(encoded_component_bytes)
}
fn at_end(&self) -> bool {
self.contents.at_end()
}
}
/// A helper struct for reading DER data. The contents are treated like a cursor, so its position
/// is updated as data is read.
struct Der<'a> {
contents: &'a [u8],
}
impl<'a> Der<'a> {
fn new(contents: &'a [u8]) -> Der<'a> {
Der { contents }
}
// In theory, a caller could encounter an error and try another operation, in which case we may
// be in an inconsistent state. As long as this implementation isn't exposed to code that would
// use it incorrectly (i.e. it stays in this module and we only expose a stateless API), it
// should be safe.
/// Given an expected tag, reads the next (tag, lengh, value) from the contents. Most
/// consumers will only be interested in the value, but some may want the entire encoded
/// contents, in which case the returned tuple can be concatenated.
fn read_tlv(&mut self, tag: u8) -> Result<(u8, Vec<u8>, &'a [u8]), Error> {
let contents = self.contents;
let (tag_read, rest) = try_read_bytes!(contents, 1);
if tag_read[0] != tag {
return Err(error_here!(ErrorType::InvalidInput));
}
let mut accumulated_length_bytes = Vec::with_capacity(4);
let (length1, rest) = try_read_bytes!(rest, 1);
accumulated_length_bytes.extend_from_slice(length1);
let (length, to_read_from) = if length1[0] < 0x80 {
(length1[0] as usize, rest)
} else if length1[0] == 0x81 {
let (length, rest) = try_read_bytes!(rest, 1);
accumulated_length_bytes.extend_from_slice(length);
if length[0] < 0x80 {
return Err(error_here!(ErrorType::InvalidInput));
}
(length[0] as usize, rest)
} else if length1[0] == 0x82 {
let (mut lengths, rest) = try_read_bytes!(rest, 2);
accumulated_length_bytes.extend_from_slice(lengths);
let length = lengths
.read_u16::<BigEndian>()
.map_err(|_| error_here!(ErrorType::LibraryFailure))?;
if length < 256 {
return Err(error_here!(ErrorType::InvalidInput));
}
(length as usize, rest)
} else {
return Err(error_here!(ErrorType::UnsupportedInput));
};
let (contents, rest) = try_read_bytes!(to_read_from, length);
self.contents = rest;
Ok((tag, accumulated_length_bytes, contents))
}
fn at_end(&self) -> bool {
self.contents.is_empty()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn der_test_empty_input() {
let input = Vec::new();
let mut der = Der::new(&input);
assert!(der.read_tlv(INTEGER).is_err());
}
#[test]
fn der_test_no_length() {
let input = vec![INTEGER];
let mut der = Der::new(&input);
assert!(der.read_tlv(INTEGER).is_err());
}
#[test]
fn der_test_empty_sequence() {
let input = vec![SEQUENCE, 0];
let mut der = Der::new(&input);
let read_result = der.read_tlv(SEQUENCE);
assert!(read_result.is_ok());
let (tag, length, sequence_bytes) = read_result.unwrap();
assert_eq!(tag, SEQUENCE);
assert_eq!(length, vec![0]);
assert_eq!(sequence_bytes.len(), 0);
assert!(der.at_end());
}
#[test]
fn der_test_not_at_end() {
let input = vec![SEQUENCE, 0, 1];
let mut der = Der::new(&input);
let read_result = der.read_tlv(SEQUENCE);
assert!(read_result.is_ok());
let (tag, length, sequence_bytes) = read_result.unwrap();
assert_eq!(tag, SEQUENCE);
assert_eq!(length, vec![0]);
assert_eq!(sequence_bytes.len(), 0);
assert!(!der.at_end());
}
#[test]
fn der_test_wrong_tag() {
let input = vec![SEQUENCE, 0];
let mut der = Der::new(&input);
assert!(der.read_tlv(INTEGER).is_err());
}
#[test]
fn der_test_truncated_two_byte_length() {
let input = vec![SEQUENCE, 0x81];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn der_test_truncated_three_byte_length() {
let input = vec![SEQUENCE, 0x82, 1];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn der_test_truncated_data() {
let input = vec![SEQUENCE, 20, 1];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn der_test_sequence() {
let input = vec![
SEQUENCE, 20, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 0, 0,
];
let mut der = Der::new(&input);
let result = der.read_tlv(SEQUENCE);
assert!(result.is_ok());
let (tag, length, value) = result.unwrap();
assert_eq!(tag, SEQUENCE);
assert_eq!(length, vec![20]);
assert_eq!(
value,
[1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 0, 0]
);
assert!(der.at_end());
}
#[test]
fn der_test_not_shortest_two_byte_length_encoding() {
let input = vec![SEQUENCE, 0x81, 1, 1];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn der_test_not_shortest_three_byte_length_encoding() {
let input = vec![SEQUENCE, 0x82, 0, 1, 1];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn der_test_indefinite_length_unsupported() {
let input = vec![SEQUENCE, 0x80, 1, 2, 3, 0x00, 0x00];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn der_test_input_too_long() {
// This isn't valid DER (the contents of the SEQUENCE are truncated), but it demonstrates
// that we don't try to read too much if we're given a long length (and also that we don't
// support lengths 2^16 and up).
let input = vec![SEQUENCE, 0x83, 0x01, 0x00, 0x01, 1, 1, 1, 1];
let mut der = Der::new(&input);
assert!(der.read_tlv(SEQUENCE).is_err());
}
#[test]
fn empty_input_fails() {
let empty = Vec::new();
assert!(read_rsa_modulus(&empty).is_err());
#[cfg(any(target_os = "macos", target_os = "ios"))]
assert!(read_ec_sig_point(&empty).is_err());
assert!(read_encoded_certificate_identifiers(&empty).is_err());
}
#[test]
fn empty_sequence_fails() {
let empty = vec![SEQUENCE | CONSTRUCTED];
assert!(read_rsa_modulus(&empty).is_err());
#[cfg(any(target_os = "macos", target_os = "ios"))]
assert!(read_ec_sig_point(&empty).is_err());
assert!(read_encoded_certificate_identifiers(&empty).is_err());
}
#[test]
fn test_read_rsa_modulus() {
let rsa_key = include_bytes!("../test/rsa.bin");
let result = read_rsa_modulus(rsa_key);
assert!(result.is_ok());
let modulus = result.unwrap();
assert_eq!(modulus, include_bytes!("../test/modulus.bin").to_vec());
}
#[test]
fn test_read_certificate_identifiers() {
let certificate = include_bytes!("../test/certificate.bin");
let result = read_encoded_certificate_identifiers(certificate);
assert!(result.is_ok());
let (serial_number, issuer, subject) = result.unwrap();
assert_eq!(
serial_number,
&[
0x02, 0x14, 0x3f, 0xed, 0x7b, 0x43, 0x47, 0x8a, 0x53, 0x42, 0x5b, 0x0d, 0x50, 0xe1,
0x37, 0x88, 0x2a, 0x20, 0x3f, 0x31, 0x17, 0x20
]
);
assert_eq!(
issuer,
&[
0x30, 0x12, 0x31, 0x10, 0x30, 0x0e, 0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x07, 0x54,
0x65, 0x73, 0x74, 0x20, 0x43, 0x41
]
);
assert_eq!(
subject,
&[
0x30, 0x1a, 0x31, 0x18, 0x30, 0x16, 0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x0f, 0x54,
0x65, 0x73, 0x74, 0x20, 0x45, 0x6e, 0x64, 0x2d, 0x65, 0x6e, 0x74, 0x69, 0x74, 0x79
]
);
}
#[test]
#[cfg(target_os = "windows")]
fn test_read_digest() {
// SEQUENCE
// SEQUENCE
// OBJECT IDENTIFIER 2.16.840.1.101.3.4.2.1 sha-256
// NULL
// OCTET STRING 1A7FCDB9A5F649F954885CFE145F3E93F0D1FA72BE980CC6EC82C70E1407C7D2
let digest_info = [
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x1, 0x65, 0x03, 0x04, 0x02,
0x01, 0x05, 0x00, 0x04, 0x20, 0x1a, 0x7f, 0xcd, 0xb9, 0xa5, 0xf6, 0x49, 0xf9, 0x54,
0x88, 0x5c, 0xfe, 0x14, 0x5f, 0x3e, 0x93, 0xf0, 0xd1, 0xfa, 0x72, 0xbe, 0x98, 0x0c,
0xc6, 0xec, 0x82, 0xc7, 0x0e, 0x14, 0x07, 0xc7, 0xd2,
];
let result = read_digest(&digest_info);
assert!(result.is_ok());
let digest = result.unwrap();
assert_eq!(
digest,
&[
0x1a, 0x7f, 0xcd, 0xb9, 0xa5, 0xf6, 0x49, 0xf9, 0x54, 0x88, 0x5c, 0xfe, 0x14, 0x5f,
0x3e, 0x93, 0xf0, 0xd1, 0xfa, 0x72, 0xbe, 0x98, 0x0c, 0xc6, 0xec, 0x82, 0xc7, 0x0e,
0x14, 0x07, 0xc7, 0xd2
]
);
}
}