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// Copyright 2015 Brian Smith.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
use crate::der::{self, FromDer};
use crate::error::{DerTypeId, Error};
use crate::verify_cert::Budget;
use pki_types::{AlgorithmIdentifier, SignatureVerificationAlgorithm};
#[cfg(feature = "alloc")]
use alloc::vec::Vec;
/// X.509 certificates and related items that are signed are almost always
/// encoded in the format "tbs||signatureAlgorithm||signature". This structure
/// captures this pattern as an owned data type.
#[cfg(feature = "alloc")]
#[derive(Clone, Debug)]
pub(crate) struct OwnedSignedData {
/// The signed data. This would be `tbsCertificate` in the case of an X.509
/// certificate, `tbsResponseData` in the case of an OCSP response, `tbsCertList`
/// in the case of a CRL, and the data nested in the `digitally-signed` construct for
/// TLS 1.2 signed data.
pub(crate) data: Vec<u8>,
/// The value of the `AlgorithmIdentifier`. This would be
/// `signatureAlgorithm` in the case of an X.509 certificate, OCSP
/// response or CRL. This would have to be synthesized in the case of TLS 1.2
/// signed data, since TLS does not identify algorithms by ASN.1 OIDs.
pub(crate) algorithm: Vec<u8>,
/// The value of the signature. This would be `signature` in an X.509
/// certificate, OCSP response or CRL. This would be the value of
/// `DigitallySigned.signature` for TLS 1.2 signed data.
pub(crate) signature: Vec<u8>,
}
#[cfg(feature = "alloc")]
impl OwnedSignedData {
/// Return a borrowed [`SignedData`] from the owned representation.
pub(crate) fn borrow(&self) -> SignedData<'_> {
SignedData {
data: untrusted::Input::from(&self.data),
algorithm: untrusted::Input::from(&self.algorithm),
signature: untrusted::Input::from(&self.signature),
}
}
}
/// X.509 certificates and related items that are signed are almost always
/// encoded in the format "tbs||signatureAlgorithm||signature". This structure
/// captures this pattern.
#[derive(Debug)]
pub(crate) struct SignedData<'a> {
/// The signed data. This would be `tbsCertificate` in the case of an X.509
/// certificate, `tbsResponseData` in the case of an OCSP response, `tbsCertList`
/// in the case of a CRL, and the data nested in the `digitally-signed` construct for
/// TLS 1.2 signed data.
pub(crate) data: untrusted::Input<'a>,
/// The value of the `AlgorithmIdentifier`. This would be
/// `signatureAlgorithm` in the case of an X.509 certificate, OCSP
/// response or CRL. This would have to be synthesized in the case of TLS 1.2
/// signed data, since TLS does not identify algorithms by ASN.1 OIDs.
pub(crate) algorithm: untrusted::Input<'a>,
/// The value of the signature. This would be `signature` in an X.509
/// certificate, OCSP response or CRL. This would be the value of
/// `DigitallySigned.signature` for TLS 1.2 signed data.
pub(crate) signature: untrusted::Input<'a>,
}
impl<'a> SignedData<'a> {
/// Parses the concatenation of "tbs||signatureAlgorithm||signature" that
/// is common in the X.509 certificate and OCSP response syntaxes.
///
/// X.509 Certificates (RFC 5280) look like this:
///
/// ```ASN.1
/// Certificate (SEQUENCE) {
/// tbsCertificate TBSCertificate,
/// signatureAlgorithm AlgorithmIdentifier,
/// signatureValue BIT STRING
/// }
/// ```
///
/// OCSP responses (RFC 6960) look like this:
/// ```ASN.1
/// BasicOCSPResponse {
/// tbsResponseData ResponseData,
/// signatureAlgorithm AlgorithmIdentifier,
/// signature BIT STRING,
/// certs [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL
/// }
/// ```
///
/// Note that this function does NOT parse the outermost `SEQUENCE` or the
/// `certs` value.
///
/// The return value's first component is the contents of
/// `tbsCertificate`/`tbsResponseData`; the second component is a `SignedData`
/// structure that can be passed to `verify_signed_data`.
///
/// The provided size_limit will enforce the largest possible outermost `SEQUENCE` this
/// function will read.
pub(crate) fn from_der(
der: &mut untrusted::Reader<'a>,
size_limit: usize,
) -> Result<(untrusted::Input<'a>, Self), Error> {
let (data, tbs) = der.read_partial(|input| {
der::expect_tag_and_get_value_limited(input, der::Tag::Sequence, size_limit)
})?;
let algorithm = der::expect_tag(der, der::Tag::Sequence)?;
let signature = der::bit_string_with_no_unused_bits(der)?;
Ok((
tbs,
SignedData {
data,
algorithm,
signature,
},
))
}
/// Convert the borrowed signed data to an [`OwnedSignedData`].
#[cfg(feature = "alloc")]
pub(crate) fn to_owned(&self) -> OwnedSignedData {
OwnedSignedData {
data: self.data.as_slice_less_safe().to_vec(),
algorithm: self.algorithm.as_slice_less_safe().to_vec(),
signature: self.signature.as_slice_less_safe().to_vec(),
}
}
}
/// Verify `signed_data` using the public key in the DER-encoded
/// SubjectPublicKeyInfo `spki` using one of the algorithms in
/// `supported_algorithms`.
///
/// The algorithm is chosen based on the algorithm information encoded in the
/// algorithm identifiers in `public_key` and `signed_data.algorithm`. The
/// ordering of the algorithms in `supported_algorithms` does not really matter,
/// but generally more common algorithms should go first, as it is scanned
/// linearly for matches.
pub(crate) fn verify_signed_data(
supported_algorithms: &[&dyn SignatureVerificationAlgorithm],
spki_value: untrusted::Input<'_>,
signed_data: &SignedData<'_>,
budget: &mut Budget,
) -> Result<(), Error> {
budget.consume_signature()?;
// We need to verify the signature in `signed_data` using the public key
// in `public_key`. In order to know which *ring* signature verification
// algorithm to use, we need to know the public key algorithm (ECDSA,
// RSA PKCS#1, etc.), the curve (if applicable), and the digest algorithm.
// `signed_data` identifies only the public key algorithm and the digest
// algorithm, and `public_key` identifies only the public key algorithm and
// the curve (if any). Thus, we have to combine information from both
// inputs to figure out which `ring::signature::VerificationAlgorithm` to
// use to verify the signature.
//
// This is all further complicated by the fact that we don't have any
// implicit knowledge about any algorithms or identifiers, since all of
// that information is encoded in `supported_algorithms.` In particular, we
// avoid hard-coding any of that information so that (link-time) dead code
// elimination will work effectively in eliminating code for unused
// algorithms.
// Parse the signature.
//
let mut found_signature_alg_match = false;
for supported_alg in supported_algorithms
.iter()
.filter(|alg| alg.signature_alg_id().as_ref() == signed_data.algorithm.as_slice_less_safe())
{
match verify_signature(
*supported_alg,
spki_value,
signed_data.data,
signed_data.signature,
) {
Err(Error::UnsupportedSignatureAlgorithmForPublicKey) => {
found_signature_alg_match = true;
continue;
}
result => {
return result;
}
}
}
if found_signature_alg_match {
Err(Error::UnsupportedSignatureAlgorithmForPublicKey)
} else {
Err(Error::UnsupportedSignatureAlgorithm)
}
}
pub(crate) fn verify_signature(
signature_alg: &dyn SignatureVerificationAlgorithm,
spki_value: untrusted::Input<'_>,
msg: untrusted::Input<'_>,
signature: untrusted::Input<'_>,
) -> Result<(), Error> {
let spki = der::read_all::<SubjectPublicKeyInfo<'_>>(spki_value)?;
if signature_alg.public_key_alg_id().as_ref() != spki.algorithm_id_value.as_slice_less_safe() {
return Err(Error::UnsupportedSignatureAlgorithmForPublicKey);
}
signature_alg
.verify_signature(
spki.key_value.as_slice_less_safe(),
msg.as_slice_less_safe(),
signature.as_slice_less_safe(),
)
.map_err(|_| Error::InvalidSignatureForPublicKey)
}
pub(crate) struct SubjectPublicKeyInfo<'a> {
algorithm_id_value: untrusted::Input<'a>,
key_value: untrusted::Input<'a>,
}
impl<'a> FromDer<'a> for SubjectPublicKeyInfo<'a> {
// Parse the public key into an algorithm OID, an optional curve OID, and the
// key value. The caller needs to check whether these match the
// `PublicKeyAlgorithm` for the `SignatureVerificationAlgorithm` that is matched when
// parsing the signature.
fn from_der(reader: &mut untrusted::Reader<'a>) -> Result<Self, Error> {
let algorithm_id_value = der::expect_tag(reader, der::Tag::Sequence)?;
let key_value = der::bit_string_with_no_unused_bits(reader)?;
Ok(SubjectPublicKeyInfo {
algorithm_id_value,
key_value,
})
}
const TYPE_ID: DerTypeId = DerTypeId::SubjectPublicKeyInfo;
}
/// Encodings of the PKIX AlgorithmIdentifier type.
///
/// This module contains a set of common values, and exists to keep the
/// names of these separate from the actual algorithm implementations.
pub mod alg_id {
use super::AlgorithmIdentifier;
// See src/data/README.md.
/// AlgorithmIdentifier for `id-ecPublicKey` with named curve `secp256r1`.
pub const ECDSA_P256: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ecdsa-p256.der"));
/// AlgorithmIdentifier for `id-ecPublicKey` with named curve `secp384r1`.
pub const ECDSA_P384: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ecdsa-p384.der"));
/// AlgorithmIdentifier for `id-ecPublicKey` with named curve `secp521r1`.
pub const ECDSA_P521: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ecdsa-p521.der"));
/// AlgorithmIdentifier for `ecdsa-with-SHA256`.
pub const ECDSA_SHA256: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ecdsa-sha256.der"));
/// AlgorithmIdentifier for `ecdsa-with-SHA384`.
pub const ECDSA_SHA384: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ecdsa-sha384.der"));
/// AlgorithmIdentifier for `ecdsa-with-SHA512`.
pub const ECDSA_SHA512: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ecdsa-sha512.der"));
/// AlgorithmIdentifier for `rsaEncryption`.
pub const RSA_ENCRYPTION: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-encryption.der"));
/// AlgorithmIdentifier for `sha256WithRSAEncryption`.
pub const RSA_PKCS1_SHA256: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-pkcs1-sha256.der"));
/// AlgorithmIdentifier for `sha384WithRSAEncryption`.
pub const RSA_PKCS1_SHA384: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-pkcs1-sha384.der"));
/// AlgorithmIdentifier for `sha512WithRSAEncryption`.
pub const RSA_PKCS1_SHA512: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-pkcs1-sha512.der"));
/// AlgorithmIdentifier for `rsassaPss` with:
///
/// - hashAlgorithm: sha256
/// - maskGenAlgorithm: mgf1 with sha256
/// - saltLength: 32
pub const RSA_PSS_SHA256: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-pss-sha256.der"));
/// AlgorithmIdentifier for `rsassaPss` with:
///
/// - hashAlgorithm: sha384
/// - maskGenAlgorithm: mgf1 with sha384
/// - saltLength: 48
pub const RSA_PSS_SHA384: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-pss-sha384.der"));
/// AlgorithmIdentifier for `rsassaPss` with:
///
/// - hashAlgorithm: sha512
/// - maskGenAlgorithm: mgf1 with sha512
/// - saltLength: 64
pub const RSA_PSS_SHA512: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-rsa-pss-sha512.der"));
/// AlgorithmIdentifier for `ED25519`.
pub const ED25519: AlgorithmIdentifier =
AlgorithmIdentifier::from_slice(include_bytes!("data/alg-ed25519.der"));
}