diff options
Diffstat (limited to 'security/manager/ssl/osclientcerts/src/util.rs')
| -rw-r--r-- | security/manager/ssl/osclientcerts/src/util.rs | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/security/manager/ssl/osclientcerts/src/util.rs b/security/manager/ssl/osclientcerts/src/util.rs new file mode 100644 index 0000000000..fc176ee751 --- /dev/null +++ b/security/manager/ssl/osclientcerts/src/util.rs @@ -0,0 +1,463 @@ +/* -*- 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 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +use byteorder::{BigEndian, NativeEndian, ReadBytesExt, WriteBytesExt}; +use std::convert::TryInto; + +/// 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_rules! unsafe_packed_field_access { + ($e:expr) => {{ + #[allow(unused_unsafe)] + let tmp = unsafe { $e }; + tmp + }}; +} + +#[cfg(target_os = "macos")] +pub const OID_BYTES_SECP256R1: &[u8] = + &[0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07]; +#[cfg(target_os = "macos")] +pub const OID_BYTES_SECP384R1: &[u8] = &[0x06, 0x05, 0x2b, 0x81, 0x04, 0x00, 0x22]; +#[cfg(target_os = "macos")] +pub const OID_BYTES_SECP521R1: &[u8] = &[0x06, 0x05, 0x2b, 0x81, 0x04, 0x00, 0x23]; + +// 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>, ()> { + 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(|_| ())?; + value_buf + .write_uint::<NativeEndian>(value_as_u64, value_size) + .map_err(|_| ())?; + 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>, ()> { + 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(()); + } + Ok(modulus_value.to_vec()) +} + +/// Given a slice of DER bytes representing a DigestInfo, extracts the bytes of the digest. +/// +/// DigestInfo ::= SEQUENCE { +/// digestAlgorithm DigestAlgorithmIdentifier, +/// digest Digest } +/// +/// DigestAlgorithmIdentifier ::= AlgorithmIdentifier +/// +/// AlgorithmIdentifier ::= SEQUENCE { +/// algorithm OBJECT IDENTIFIER, +/// parameters ANY DEFINED BY algorithm OPTIONAL } +/// +/// Digest ::= OCTET STRING +#[cfg(target_os = "windows")] +pub fn read_digest<'a>(digest_info: &'a [u8]) -> Result<&'a [u8], ()> { + let mut sequence = Sequence::new(digest_info)?; + let _ = sequence.read_sequence()?; + let digest = sequence.read_octet_string()?; + if !sequence.at_end() { + error!("read_digest: extra input"); + return Err(()); + } + Ok(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(target_os = "macos")] +pub fn read_ec_sig_point<'a>(signature: &'a [u8]) -> Result<(&'a [u8], &'a [u8]), ()> { + let mut sequence = Sequence::new(signature)?; + let r = sequence.read_unsigned_integer()?; + let s = sequence.read_unsigned_integer()?; + if !sequence.at_end() { + return Err(()); + } + Ok((r, s)) +} + +/// Given a slice of DER bytes representing an X.509 certificate, extracts the encoded serial +/// number. 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, +/// ... +/// +/// CertificateSerialNumber ::= INTEGER +pub fn read_encoded_serial_number(certificate: &[u8]) -> Result<Vec<u8>, ()> { + 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)?; + Ok(serial_number) +} + +/// 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(()); + } + $data.split_at($len) + }}; +} + +/// ASN.1 tag identifying an integer. +const INTEGER: u8 = 0x02; +/// ASN.1 tag identifying an octet string. +#[cfg(target_os = "windows")] +const OCTET_STRING: u8 = 0x04; +/// 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>, ()> { + 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(()); + } + Ok(Sequence { + contents: Der::new(sequence_bytes), + }) + } + + // TODO: we're not exhaustively validating this integer + fn read_unsigned_integer(&mut self) -> Result<&'a [u8], ()> { + let (_, _, bytes) = self.contents.read_tlv(INTEGER)?; + if bytes.is_empty() { + return Err(()); + } + // 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) + } + } + + #[cfg(target_os = "windows")] + fn read_octet_string(&mut self) -> Result<&'a [u8], ()> { + let (_, _, bytes) = self.contents.read_tlv(OCTET_STRING)?; + Ok(bytes) + } + + fn read_sequence(&mut self) -> Result<Sequence<'a>, ()> { + 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], ()> { + 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>, ()> { + 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]), ()> { + let contents = self.contents; + let (tag_read, rest) = try_read_bytes!(contents, 1); + if tag_read[0] != tag { + return Err(()); + } + 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(()); + } + (length[0] as usize, rest) + } else if length1[0] == 0x82 { + let (lengths, rest) = try_read_bytes!(rest, 2); + accumulated_length_bytes.extend_from_slice(lengths); + let length = (&mut &lengths[..]) + .read_u16::<BigEndian>() + .map_err(|_| ())?; + if length < 256 { + return Err(()); + } + (length as usize, rest) + } else { + return Err(()); + }; + 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(target_os = "macos")] + assert!(read_ec_sig_point(&empty).is_err()); + assert!(read_encoded_serial_number(&empty).is_err()); + } + + #[test] + fn empty_sequence_fails() { + let empty = vec![SEQUENCE | CONSTRUCTED]; + assert!(read_rsa_modulus(&empty).is_err()); + #[cfg(target_os = "macos")] + assert!(read_ec_sig_point(&empty).is_err()); + assert!(read_encoded_serial_number(&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_serial_number() { + let certificate = include_bytes!("../test/certificate.bin"); + let result = read_encoded_serial_number(certificate); + assert!(result.is_ok()); + let serial_number = 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 + ] + ); + } + + #[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 + ] + ); + } +} |