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// 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 https://mozilla.org/MPL/2.0/.
//! Defines high-level interface to X.509 certificates.
use {
crate::{
algorithm::DigestAlgorithm, asn1time::Time, rfc2986, rfc3280::Name, rfc5280, rfc5652,
rfc5958::Attributes, rfc8017::RsaPublicKey, signing::Sign, InMemorySigningKeyPair,
KeyAlgorithm, KeyInfoSigner, SignatureAlgorithm, X509CertificateError as Error,
},
bcder::{
decode::Constructed,
encode::Values,
int::Integer,
string::{BitString, OctetString},
ConstOid, Mode, Oid,
},
bytes::Bytes,
chrono::{DateTime, Duration, Utc},
der::{Decode, Document},
ring::signature as ringsig,
signature::Signer,
spki::EncodePublicKey,
std::{
cmp::Ordering,
collections::HashSet,
fmt::{Debug, Formatter},
hash::{Hash, Hasher},
io::Write,
ops::{Deref, DerefMut},
},
};
/// Key Usage extension.
///
/// 2.5.29.15
const OID_EXTENSION_KEY_USAGE: ConstOid = Oid(&[85, 29, 15]);
/// Basic Constraints X.509 extension.
///
/// 2.5.29.19
const OID_EXTENSION_BASIC_CONSTRAINTS: ConstOid = Oid(&[85, 29, 19]);
/// Provides an interface to the RFC 5280 [rfc5280::Certificate] ASN.1 type.
///
/// This type provides the main high-level API that this crate exposes
/// for reading and writing X.509 certificates.
///
/// Instances are backed by an actual ASN.1 [rfc5280::Certificate] instance.
/// Read operations are performed against the raw ASN.1 values. Mutations
/// result in mutations of the ASN.1 data structures.
///
/// Instances can be converted to/from [rfc5280::Certificate] using traits.
/// [AsRef]/[AsMut] are implemented to obtain a reference to the backing
/// [rfc5280::Certificate].
///
/// We have chosen not to implement [Deref]/[DerefMut] because we don't
/// want to pollute the type's API with lower-level ASN.1 primitives.
///
/// This type does not track the original data from which it came.
/// If you want a type that does that, consider [CapturedX509Certificate],
/// which implements [Deref] and therefore behaves like this type.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct X509Certificate(rfc5280::Certificate);
impl X509Certificate {
/// Construct an instance by parsing DER encoded ASN.1 data.
pub fn from_der(data: impl AsRef<[u8]>) -> Result<Self, Error> {
let cert = Constructed::decode(data.as_ref(), Mode::Der, |cons| {
rfc5280::Certificate::take_from(cons)
})?;
Ok(Self(cert))
}
/// Construct an instance by parsing BER encoded ASN.1 data.
///
/// X.509 certificates are likely (and should be) using DER encoding.
/// However, some specifications do mandate the use of BER, so this
/// method is provided.
pub fn from_ber(data: impl AsRef<[u8]>) -> Result<Self, Error> {
let cert = Constructed::decode(data.as_ref(), Mode::Ber, |cons| {
rfc5280::Certificate::take_from(cons)
})?;
Ok(Self(cert))
}
/// Construct an instance by parsing PEM encoded ASN.1 data.
///
/// The data is a human readable string likely containing
/// `--------- BEGIN CERTIFICATE ----------`.
pub fn from_pem(data: impl AsRef<[u8]>) -> Result<Self, Error> {
let data = pem::parse(data.as_ref()).map_err(Error::PemDecode)?;
Self::from_der(data.contents())
}
/// Construct instances by parsing PEM with potentially multiple records.
///
/// By default, we only look for `--------- BEGIN CERTIFICATE --------`
/// entries and silently ignore unknown ones. If you would like to specify
/// an alternate set of tags (this is the value after the `BEGIN`) to search,
/// call [Self::from_pem_multiple_tags].
pub fn from_pem_multiple(data: impl AsRef<[u8]>) -> Result<Vec<Self>, Error> {
Self::from_pem_multiple_tags(data, &["CERTIFICATE"])
}
/// Construct instances by parsing PEM armored DER encoded certificates with specific PEM tags.
///
/// This is like [Self::from_pem_multiple] except you control the filter for
/// which `BEGIN <tag>` values are filtered through to the DER parser.
pub fn from_pem_multiple_tags(
data: impl AsRef<[u8]>,
tags: &[&str],
) -> Result<Vec<Self>, Error> {
let pem = pem::parse_many(data.as_ref()).map_err(Error::PemDecode)?;
pem.into_iter()
.filter(|pem| tags.contains(&pem.tag()))
.map(|pem| Self::from_der(pem.contents()))
.collect::<Result<_, _>>()
}
/// Obtain the serial number as the ASN.1 [Integer] type.
pub fn serial_number_asn1(&self) -> &Integer {
&self.0.tbs_certificate.serial_number
}
/// Obtain the certificate's subject, as its ASN.1 [Name] type.
pub fn subject_name(&self) -> &Name {
&self.0.tbs_certificate.subject
}
/// Obtain the Common Name (CN) attribute from the certificate's subject, if set and decodable.
pub fn subject_common_name(&self) -> Option<String> {
self.0
.tbs_certificate
.subject
.iter_common_name()
.next()
.and_then(|cn| cn.to_string().ok())
}
/// Obtain the certificate's issuer, as its ASN.1 [Name] type.
pub fn issuer_name(&self) -> &Name {
&self.0.tbs_certificate.issuer
}
/// Obtain the Common Name (CN) attribute from the certificate's issuer, if set and decodable.
pub fn issuer_common_name(&self) -> Option<String> {
self.0
.tbs_certificate
.issuer
.iter_common_name()
.next()
.and_then(|cn| cn.to_string().ok())
}
/// Iterate over extensions defined in this certificate.
pub fn iter_extensions(&self) -> impl Iterator<Item = &crate::rfc5280::Extension> {
self.0.iter_extensions()
}
/// Encode the certificate data structure using DER encoding.
///
/// (This is the common ASN.1 encoding format for X.509 certificates.)
///
/// This always serializes the internal ASN.1 data structure. If you
/// call this on a wrapper type that has retained a copy of the original
/// data, this may emit different data than that copy.
pub fn encode_der_to(&self, fh: &mut impl Write) -> Result<(), std::io::Error> {
self.0.encode_ref().write_encoded(Mode::Der, fh)
}
/// Encode the certificate data structure use BER encoding.
pub fn encode_ber_to(&self, fh: &mut impl Write) -> Result<(), std::io::Error> {
self.0.encode_ref().write_encoded(Mode::Ber, fh)
}
/// Encode the internal ASN.1 data structures to DER.
pub fn encode_der(&self) -> Result<Vec<u8>, std::io::Error> {
let mut buffer = Vec::<u8>::new();
self.encode_der_to(&mut buffer)?;
Ok(buffer)
}
/// Obtain the BER encoded representation of this certificate.
pub fn encode_ber(&self) -> Result<Vec<u8>, std::io::Error> {
let mut buffer = Vec::<u8>::new();
self.encode_ber_to(&mut buffer)?;
Ok(buffer)
}
/// Encode the certificate to PEM.
///
/// This will write a human-readable string with `------ BEGIN CERTIFICATE -------`
/// armoring. This is a very common method for encoding certificates.
///
/// The underlying binary data is DER encoded.
pub fn write_pem(&self, fh: &mut impl Write) -> Result<(), std::io::Error> {
let encoded = pem::Pem::new("CERTIFICATE", self.encode_der()?).to_string();
fh.write_all(encoded.as_bytes())
}
/// Encode the certificate to a PEM string.
pub fn encode_pem(&self) -> Result<String, std::io::Error> {
Ok(pem::Pem::new("CERTIFICATE", self.encode_der()?).to_string())
}
/// Attempt to resolve a known [KeyAlgorithm] used by the private key associated with this certificate.
///
/// If this crate isn't aware of the OID associated with the key algorithm,
/// `None` is returned.
pub fn key_algorithm(&self) -> Option<KeyAlgorithm> {
KeyAlgorithm::try_from(&self.0.tbs_certificate.subject_public_key_info.algorithm).ok()
}
/// Obtain the OID of the private key's algorithm.
pub fn key_algorithm_oid(&self) -> &Oid {
&self
.0
.tbs_certificate
.subject_public_key_info
.algorithm
.algorithm
}
/// Obtain the [SignatureAlgorithm this certificate will use.
///
/// Returns [None] if we failed to resolve an instance (probably because we don't
/// recognize the algorithm).
pub fn signature_algorithm(&self) -> Option<SignatureAlgorithm> {
SignatureAlgorithm::try_from(&self.0.tbs_certificate.signature.algorithm).ok()
}
/// Obtain the OID of the signature algorithm this certificate will use.
pub fn signature_algorithm_oid(&self) -> &Oid {
&self.0.tbs_certificate.signature.algorithm
}
/// Obtain the [SignatureAlgorithm] used to sign this certificate.
///
/// Returns [None] if we failed to resolve an instance (probably because we
/// don't recognize that algorithm).
pub fn signature_signature_algorithm(&self) -> Option<SignatureAlgorithm> {
SignatureAlgorithm::try_from(&self.0.signature_algorithm).ok()
}
/// Obtain the OID of the signature algorithm used to sign this certificate.
pub fn signature_signature_algorithm_oid(&self) -> &Oid {
&self.0.signature_algorithm.algorithm
}
/// Obtain the raw data constituting this certificate's public key.
///
/// A copy of the data is returned.
pub fn public_key_data(&self) -> Bytes {
self.0
.tbs_certificate
.subject_public_key_info
.subject_public_key
.octet_bytes()
}
/// Attempt to parse the public key data as [RsaPublicKey] parameters.
///
/// Note that the raw integer value for modulus has a leading 0 byte. So its
/// raw length will be 1 greater than key length. e.g. an RSA 2048 key will
/// have `value.modulus.as_slice().len() == 257` instead of `256`.
pub fn rsa_public_key_data(&self) -> Result<RsaPublicKey, Error> {
let der = self.public_key_data();
Ok(Constructed::decode(
der.as_ref(),
Mode::Der,
RsaPublicKey::take_from,
)?)
}
/// Compare 2 instances, sorting them so the issuer comes before the issued.
///
/// This function examines the [Self::issuer_name] and [Self::subject_name]
/// fields of 2 certificates, attempting to sort them so the issuing
/// certificate comes before the issued certificate.
///
/// This function performs a strict compare of the ASN.1 [Name] data.
/// The assumption here is that the issuing certificate's subject [Name]
/// is identical to the issued's issuer [Name]. This assumption is often
/// true. But it likely isn't always true, so this function may not produce
/// reliable results.
pub fn compare_issuer(&self, other: &Self) -> Ordering {
// Self signed certificate has no ordering.
if self.0.tbs_certificate.subject == self.0.tbs_certificate.issuer {
Ordering::Equal
// We were issued by the other certificate. The issuer comes first.
} else if self.0.tbs_certificate.issuer == other.0.tbs_certificate.subject {
Ordering::Greater
} else if self.0.tbs_certificate.subject == other.0.tbs_certificate.issuer {
// We issued the other certificate. We come first.
Ordering::Less
} else {
Ordering::Equal
}
}
/// Whether the subject [Name] is also the issuer's [Name].
///
/// This might be a way of determining if a certificate is self-signed.
/// But there can likely be false negatives due to differences in ASN.1
/// encoding of the underlying data. So we don't claim this is a test for
/// being self-signed.
pub fn subject_is_issuer(&self) -> bool {
self.0.tbs_certificate.subject == self.0.tbs_certificate.issuer
}
/// Obtain the fingerprint for this certificate given a digest algorithm.
pub fn fingerprint(
&self,
algorithm: DigestAlgorithm,
) -> Result<ring::digest::Digest, std::io::Error> {
let raw = self.encode_der()?;
let mut h = algorithm.digester();
h.update(&raw);
Ok(h.finish())
}
/// Obtain the SHA-1 fingerprint of this certificate.
pub fn sha1_fingerprint(&self) -> Result<ring::digest::Digest, std::io::Error> {
self.fingerprint(DigestAlgorithm::Sha1)
}
/// Obtain the SHA-256 fingerprint of this certificate.
pub fn sha256_fingerprint(&self) -> Result<ring::digest::Digest, std::io::Error> {
self.fingerprint(DigestAlgorithm::Sha256)
}
/// Obtain the raw [rfc5280::TbsCertificate] for this certificate.
pub fn tbs_certificate(&self) -> &rfc5280::TbsCertificate {
&self.0.tbs_certificate
}
/// Obtain the certificate validity "not before" time.
pub fn validity_not_before(&self) -> DateTime<Utc> {
self.0.tbs_certificate.validity.not_before.clone().into()
}
/// Obtain the certificate validity "not after" time.
pub fn validity_not_after(&self) -> DateTime<Utc> {
self.0.tbs_certificate.validity.not_after.clone().into()
}
/// Determine whether a time is between the validity constraints in the certificate.
///
/// i.e. check whether a certificate is "expired."
///
/// Receives a date time to check against.
///
/// If `None`, the current time is used. This relies on the machine's
/// wall clock to be accurate, of course.
pub fn time_constraints_valid(&self, compare_time: Option<DateTime<Utc>>) -> bool {
let compare_time = compare_time.unwrap_or(Utc::now());
compare_time >= self.validity_not_before() && compare_time <= self.validity_not_after()
}
}
impl From<rfc5280::Certificate> for X509Certificate {
fn from(v: rfc5280::Certificate) -> Self {
Self(v)
}
}
impl From<X509Certificate> for rfc5280::Certificate {
fn from(v: X509Certificate) -> Self {
v.0
}
}
impl AsRef<rfc5280::Certificate> for X509Certificate {
fn as_ref(&self) -> &rfc5280::Certificate {
&self.0
}
}
impl AsMut<rfc5280::Certificate> for X509Certificate {
fn as_mut(&mut self) -> &mut rfc5280::Certificate {
&mut self.0
}
}
impl EncodePublicKey for X509Certificate {
fn to_public_key_der(&self) -> spki::Result<Document> {
let mut data = vec![];
self.0
.tbs_certificate
.subject_public_key_info
.encode_ref()
.write_encoded(Mode::Der, &mut data)
.map_err(|_| spki::Error::Asn1(der::Error::new(der::ErrorKind::Failed, 0u8.into())))?;
Document::from_der(&data).map_err(spki::Error::Asn1)
}
}
#[derive(Clone, Eq, PartialEq)]
enum OriginalData {
Ber(Vec<u8>),
Der(Vec<u8>),
}
impl Debug for OriginalData {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!(
"{}({})",
match self {
Self::Ber(_) => "Ber",
Self::Der(_) => "Der",
},
match self {
Self::Ber(data) => hex::encode(data),
Self::Der(data) => hex::encode(data),
}
))
}
}
/// Represents an immutable (read-only) X.509 certificate that was parsed from data.
///
/// This type implements [Deref] but not [DerefMut], so only functions
/// taking a non-mutable instance are usable.
///
/// A copy of the certificate's raw backing data is stored, facilitating
/// subsequent access.
#[derive(Clone, Debug)]
pub struct CapturedX509Certificate {
original: OriginalData,
inner: X509Certificate,
}
impl CapturedX509Certificate {
/// Construct an instance from DER encoded data.
///
/// A copy of this data will be stored in the instance and is guaranteed
/// to be immutable for the lifetime of the instance. The original constructing
/// data can be retrieved later.
pub fn from_der(data: impl Into<Vec<u8>>) -> Result<Self, Error> {
let der_data = data.into();
let inner = X509Certificate::from_der(&der_data)?;
Ok(Self {
original: OriginalData::Der(der_data),
inner,
})
}
/// Construct an instance from BER encoded data.
///
/// A copy of this data will be stored in the instance and is guaranteed
/// to be immutable for the lifetime of the instance, allowing it to
/// be retrieved later.
pub fn from_ber(data: impl Into<Vec<u8>>) -> Result<Self, Error> {
let data = data.into();
let inner = X509Certificate::from_ber(&data)?;
Ok(Self {
original: OriginalData::Ber(data),
inner,
})
}
/// Construct an instance by parsing PEM encoded ASN.1 data.
///
/// The data is a human readable string likely containing
/// `--------- BEGIN CERTIFICATE ----------`.
pub fn from_pem(data: impl AsRef<[u8]>) -> Result<Self, Error> {
let data = pem::parse(data.as_ref()).map_err(Error::PemDecode)?;
Self::from_der(data.contents())
}
/// Construct instances by parsing PEM with potentially multiple records.
///
/// By default, we only look for `--------- BEGIN CERTIFICATE --------`
/// entries and silently ignore unknown ones. If you would like to specify
/// an alternate set of tags (this is the value after the `BEGIN`) to search,
/// call [Self::from_pem_multiple_tags].
pub fn from_pem_multiple(data: impl AsRef<[u8]>) -> Result<Vec<Self>, Error> {
Self::from_pem_multiple_tags(data, &["CERTIFICATE"])
}
/// Construct instances by parsing PEM armored DER encoded certificates with specific PEM tags.
///
/// This is like [Self::from_pem_multiple] except you control the filter for
/// which `BEGIN <tag>` values are filtered through to the DER parser.
pub fn from_pem_multiple_tags(
data: impl AsRef<[u8]>,
tags: &[&str],
) -> Result<Vec<Self>, Error> {
let pem = pem::parse_many(data.as_ref()).map_err(Error::PemDecode)?;
pem.into_iter()
.filter(|pem| tags.contains(&pem.tag()))
.map(|pem| Self::from_der(pem.contents()))
.collect::<Result<_, _>>()
}
/// Obtain the DER data that was used to construct this instance.
///
/// The data is guaranteed to not have been modified since the instance
/// was constructed.
pub fn constructed_data(&self) -> &[u8] {
match &self.original {
OriginalData::Ber(data) => data,
OriginalData::Der(data) => data,
}
}
/// Encode the original contents of this certificate to PEM.
pub fn encode_pem(&self) -> String {
pem::Pem::new("CERTIFICATE", self.constructed_data()).to_string()
}
/// Verify that another certificate, `other`, signed this certificate.
///
/// If this is a self-signed certificate, you can pass `self` as the 2nd
/// argument.
///
/// This function isn't exposed on [X509Certificate] because the exact
/// bytes constituting the certificate's internals need to be consulted
/// to verify signatures. And since this type tracks the underlying
/// bytes, we are guaranteed to have a pristine copy.
pub fn verify_signed_by_certificate(
&self,
other: impl AsRef<X509Certificate>,
) -> Result<(), Error> {
let public_key = other
.as_ref()
.0
.tbs_certificate
.subject_public_key_info
.subject_public_key
.octet_bytes();
self.verify_signed_by_public_key(public_key)
}
/// Verify a signature over signed data purportedly signed by this certificate.
///
/// This is a wrapper to [Self::verify_signed_data_with_algorithm()] that will derive
/// the verification algorithm from the public key type type and the signature algorithm
/// indicated in this certificate. Typically these align. However, it is possible for
/// a signature to be produced with a different digest algorithm from that indicated
/// in this certificate.
pub fn verify_signed_data(
&self,
signed_data: impl AsRef<[u8]>,
signature: impl AsRef<[u8]>,
) -> Result<(), Error> {
let key_algorithm = KeyAlgorithm::try_from(self.key_algorithm_oid())?;
let signature_algorithm = SignatureAlgorithm::try_from(self.signature_algorithm_oid())?;
let verify_algorithm = signature_algorithm.resolve_verification_algorithm(key_algorithm)?;
self.verify_signed_data_with_algorithm(signed_data, signature, verify_algorithm)
}
/// Verify a signature over signed data using an explicit verification algorithm.
///
/// This is like [Self::verify_signed_data()] except the verification algorithm to use
/// is passed in instead of derived from the default algorithm for the signing key's
/// type.
pub fn verify_signed_data_with_algorithm(
&self,
signed_data: impl AsRef<[u8]>,
signature: impl AsRef<[u8]>,
verify_algorithm: &'static dyn ringsig::VerificationAlgorithm,
) -> Result<(), Error> {
let public_key = ringsig::UnparsedPublicKey::new(verify_algorithm, self.public_key_data());
public_key
.verify(signed_data.as_ref(), signature.as_ref())
.map_err(|_| Error::CertificateSignatureVerificationFailed)
}
/// Verifies that this certificate was cryptographically signed using raw public key data from a signing key.
///
/// This function does the low-level work of extracting the signature and
/// verification details from the current certificate and figuring out
/// the correct combination of cryptography settings to apply to perform
/// signature verification.
///
/// In many cases, an X.509 certificate is signed by another certificate. And
/// since the public key is embedded in the X.509 certificate, it is easier
/// to go through [Self::verify_signed_by_certificate] instead.
pub fn verify_signed_by_public_key(
&self,
public_key_data: impl AsRef<[u8]>,
) -> Result<(), Error> {
// Always verify against the original content, as the inner
// certificate could be mutated via the mutable wrapper of this
// type.
let this_cert = match &self.original {
OriginalData::Ber(data) => X509Certificate::from_ber(data),
OriginalData::Der(data) => X509Certificate::from_der(data),
}
.expect("certificate re-parse should never fail");
let signed_data = this_cert
.0
.tbs_certificate
.raw_data
.as_ref()
.expect("original certificate data should have persisted as part of re-parse");
let signature = this_cert.0.signature.octet_bytes();
let key_algorithm = KeyAlgorithm::try_from(
&this_cert
.0
.tbs_certificate
.subject_public_key_info
.algorithm,
)?;
let signature_algorithm = SignatureAlgorithm::try_from(&this_cert.0.signature_algorithm)?;
let verify_algorithm = signature_algorithm.resolve_verification_algorithm(key_algorithm)?;
let public_key = ringsig::UnparsedPublicKey::new(verify_algorithm, public_key_data);
public_key
.verify(signed_data, &signature)
.map_err(|_| Error::CertificateSignatureVerificationFailed)
}
/// Attempt to find the issuing certificate of this one.
///
/// Given an iterable of certificates, we find the first certificate
/// where we are able to verify that our signature was made by their public
/// key.
///
/// This function can yield false negatives for cases where we don't
/// support the signature algorithm on the incoming certificates.
pub fn find_signing_certificate<'a>(
&self,
mut certs: impl Iterator<Item = &'a Self>,
) -> Option<&'a Self> {
certs.find(|candidate| self.verify_signed_by_certificate(candidate).is_ok())
}
/// Attempt to resolve the signing chain of this certificate.
///
/// Given an iterable of certificates, we recursively resolve the
/// chain of certificates that signed this one until we are no longer able
/// to find any more certificates in the input set.
///
/// Like [Self::find_signing_certificate], this can yield false
/// negatives (read: an incomplete chain) due to run-time failures,
/// such as lack of support for a certificate's signature algorithm.
///
/// As a certificate is encountered, it is removed from the set of
/// future candidates.
///
/// The traversal ends when we get to an identical certificate (its
/// DER data is equivalent) or we couldn't find a certificate in
/// the remaining set that signed the last one.
///
/// Because we need to recursively verify certificates, the incoming
/// iterator is buffered.
pub fn resolve_signing_chain<'a>(
&self,
certs: impl Iterator<Item = &'a Self>,
) -> Vec<&'a Self> {
// The logic here is a bit wonky. As we build up the collection of certificates,
// we want to filter out ourself and remove duplicates. We remove duplicates by
// storing encountered certificates in a HashSet.
#[allow(clippy::mutable_key_type)]
let mut seen = HashSet::new();
let mut remaining = vec![];
for cert in certs {
if cert == self || seen.contains(cert) {
continue;
} else {
remaining.push(cert);
seen.insert(cert);
}
}
drop(seen);
let mut chain = vec![];
let mut last_cert = self;
while let Some(issuer) = last_cert.find_signing_certificate(remaining.iter().copied()) {
chain.push(issuer);
last_cert = issuer;
remaining = remaining
.drain(..)
.filter(|cert| *cert != issuer)
.collect::<Vec<_>>();
}
chain
}
}
impl PartialEq for CapturedX509Certificate {
fn eq(&self, other: &Self) -> bool {
self.constructed_data() == other.constructed_data()
}
}
impl Eq for CapturedX509Certificate {}
impl Hash for CapturedX509Certificate {
fn hash<H: Hasher>(&self, state: &mut H) {
state.write(self.constructed_data());
}
}
impl Deref for CapturedX509Certificate {
type Target = X509Certificate;
fn deref(&self) -> &Self::Target {
&self.inner
}
}
impl AsRef<X509Certificate> for CapturedX509Certificate {
fn as_ref(&self) -> &X509Certificate {
&self.inner
}
}
impl AsRef<rfc5280::Certificate> for CapturedX509Certificate {
fn as_ref(&self) -> &rfc5280::Certificate {
self.inner.as_ref()
}
}
impl TryFrom<&X509Certificate> for CapturedX509Certificate {
type Error = Error;
fn try_from(cert: &X509Certificate) -> Result<Self, Self::Error> {
let mut buffer = Vec::<u8>::new();
cert.encode_der_to(&mut buffer)?;
Self::from_der(buffer)
}
}
impl TryFrom<X509Certificate> for CapturedX509Certificate {
type Error = Error;
fn try_from(cert: X509Certificate) -> Result<Self, Self::Error> {
let mut buffer = Vec::<u8>::new();
cert.encode_der_to(&mut buffer)?;
Self::from_der(buffer)
}
}
impl From<CapturedX509Certificate> for rfc5280::Certificate {
fn from(cert: CapturedX509Certificate) -> Self {
cert.inner.0
}
}
/// Provides a mutable wrapper to an X.509 certificate that was parsed from data.
///
/// This is like [CapturedX509Certificate] except it implements [DerefMut],
/// enabling you to modify the certificate while still being able to access
/// the raw data the certificate is backed by. However, mutations are
/// only performed against the parsed ASN.1 data structure, not the original
/// data it was constructed with.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct MutableX509Certificate(CapturedX509Certificate);
impl Deref for MutableX509Certificate {
type Target = X509Certificate;
fn deref(&self) -> &Self::Target {
&self.0.inner
}
}
impl DerefMut for MutableX509Certificate {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0.inner
}
}
impl From<CapturedX509Certificate> for MutableX509Certificate {
fn from(cert: CapturedX509Certificate) -> Self {
Self(cert)
}
}
/// Whether one certificate is a subset of another certificate.
///
/// This returns true iff the two certificates have the same serial number
/// and every `Name` attribute in the first certificate is present in the other.
pub fn certificate_is_subset_of(
a_serial: &Integer,
a_name: &Name,
b_serial: &Integer,
b_name: &Name,
) -> bool {
if a_serial != b_serial {
return false;
}
let Name::RdnSequence(a_sequence) = &a_name;
let Name::RdnSequence(b_sequence) = &b_name;
a_sequence.iter().all(|rdn| b_sequence.contains(rdn))
}
/// X.509 extension to define how a certificate can be used.
///
/// ```asn.1
/// KeyUsage ::= BIT STRING {
/// digitalSignature(0),
/// nonRepudiation(1),
/// keyEncipherment(2),
/// dataEncipherment(3),
/// keyAgreement(4),
/// keyCertSign(5),
/// cRLSign(6)
/// }
/// ```
pub enum KeyUsage {
DigitalSignature,
NonRepudiation,
KeyEncipherment,
DataEncipherment,
KeyAgreement,
KeyCertSign,
CrlSign,
}
impl From<KeyUsage> for u8 {
fn from(ku: KeyUsage) -> Self {
match ku {
KeyUsage::DigitalSignature => 0,
KeyUsage::NonRepudiation => 1,
KeyUsage::KeyEncipherment => 2,
KeyUsage::DataEncipherment => 3,
KeyUsage::KeyAgreement => 4,
KeyUsage::KeyCertSign => 5,
KeyUsage::CrlSign => 6,
}
}
}
/// Interface for constructing new X.509 certificates.
///
/// This holds fields for various certificate metadata and allows you
/// to incrementally derive a new X.509 certificate.
///
/// The certificate is populated with defaults:
///
/// * The serial number is 1.
/// * The time validity is now until 1 hour from now.
/// * There is no issuer. If no attempt is made to define an issuer,
/// the subject will be copied to the issuer field and this will be
/// a self-signed certificate.
///
/// This type can also be used to produce certificate signing requests. In this mode,
/// only the subject value and additional registered attributes are meaningful.
pub struct X509CertificateBuilder {
subject: Name,
issuer: Option<Name>,
extensions: rfc5280::Extensions,
serial_number: i64,
not_before: chrono::DateTime<Utc>,
not_after: chrono::DateTime<Utc>,
csr_attributes: Attributes,
}
impl Default for X509CertificateBuilder {
fn default() -> Self {
let not_before = Utc::now();
let not_after = not_before + Duration::hours(1);
Self {
subject: Name::default(),
issuer: None,
extensions: rfc5280::Extensions::default(),
serial_number: 1,
not_before,
not_after,
csr_attributes: Attributes::default(),
}
}
}
impl X509CertificateBuilder {
/// Deprecated. Use [Self::default()] instead.
#[deprecated]
pub fn new() -> Self {
Self::default()
}
/// Obtain a mutable reference to the subject [Name].
///
/// The type has functions that will allow you to add attributes with ease.
pub fn subject(&mut self) -> &mut Name {
&mut self.subject
}
/// Obtain a mutable reference to the issuer [Name].
///
/// If no issuer has been created yet, an empty one will be created.
pub fn issuer(&mut self) -> &mut Name {
self.issuer.get_or_insert_with(Name::default)
}
/// Set the serial number for the certificate.
pub fn serial_number(&mut self, value: i64) {
self.serial_number = value;
}
/// Obtain the raw certificate extensions.
pub fn extensions(&self) -> &rfc5280::Extensions {
&self.extensions
}
/// Obtain a mutable reference to raw certificate extensions.
pub fn extensions_mut(&mut self) -> &mut rfc5280::Extensions {
&mut self.extensions
}
/// Add an extension to the certificate with its value as pre-encoded DER data.
pub fn add_extension_der_data(&mut self, oid: Oid, critical: bool, data: impl AsRef<[u8]>) {
self.extensions.push(rfc5280::Extension {
id: oid,
critical: Some(critical),
value: OctetString::new(Bytes::copy_from_slice(data.as_ref())),
});
}
/// Set the expiration time in terms of [Duration] since its currently set start time.
pub fn validity_duration(&mut self, duration: Duration) {
self.not_after = self.not_before + duration;
}
/// Add a basic constraint extension that this isn't a CA certificate.
pub fn constraint_not_ca(&mut self) {
self.extensions.push(rfc5280::Extension {
id: Oid(OID_EXTENSION_BASIC_CONSTRAINTS.as_ref().into()),
critical: Some(true),
value: OctetString::new(Bytes::copy_from_slice(&[0x30, 00])),
});
}
/// Add a key usage extension.
pub fn key_usage(&mut self, key_usage: KeyUsage) {
let value: u8 = key_usage.into();
self.extensions.push(rfc5280::Extension {
id: Oid(OID_EXTENSION_KEY_USAGE.as_ref().into()),
critical: Some(true),
// Value is a bit string. We just encode it manually since it is easy.
value: OctetString::new(Bytes::copy_from_slice(&[3, 2, 7, 128 | value])),
});
}
/// Add an [Attribute] to a future certificate signing requests.
///
/// Has no effect on regular certificate creation: only if creating certificate
/// signing requests.
pub fn add_csr_attribute(&mut self, attribute: rfc5652::Attribute) {
self.csr_attributes.push(attribute);
}
/// Create a new certificate given settings using the provided key pair.
pub fn create_with_key_pair(
&self,
key_pair: &InMemorySigningKeyPair,
) -> Result<CapturedX509Certificate, Error> {
let key_pair_signature_algorithm = key_pair.signature_algorithm();
let issuer = if let Some(issuer) = &self.issuer {
issuer
} else {
&self.subject
};
let tbs_certificate = rfc5280::TbsCertificate {
version: Some(rfc5280::Version::V3),
serial_number: self.serial_number.into(),
signature: key_pair_signature_algorithm?.into(),
issuer: issuer.clone(),
validity: rfc5280::Validity {
not_before: Time::from(self.not_before),
not_after: Time::from(self.not_after),
},
subject: self.subject.clone(),
subject_public_key_info: rfc5280::SubjectPublicKeyInfo {
algorithm: key_pair
.key_algorithm()
.expect("InMemorySigningKeyPair always has known key algorithm")
.into(),
subject_public_key: BitString::new(0, key_pair.public_key_data()),
},
issuer_unique_id: None,
subject_unique_id: None,
extensions: if self.extensions.is_empty() {
None
} else {
Some(self.extensions.clone())
},
raw_data: None,
};
// Now encode the TBS certificate so we can sign it with the private key
// and include its signature.
let mut tbs_der = Vec::<u8>::new();
tbs_certificate
.encode_ref()
.write_encoded(Mode::Der, &mut tbs_der)?;
let signature = key_pair.try_sign(&tbs_der)?;
let signature_algorithm = key_pair.signature_algorithm()?;
let cert = rfc5280::Certificate {
tbs_certificate,
signature_algorithm: signature_algorithm.into(),
signature: BitString::new(0, Bytes::copy_from_slice(signature.as_ref())),
};
let cert = X509Certificate::from(cert);
let cert_der = cert.encode_der()?;
CapturedX509Certificate::from_der(cert_der)
}
/// Create a new certificate given settings, using a randomly generated key pair.
pub fn create_with_random_keypair(
&self,
key_algorithm: KeyAlgorithm,
) -> Result<(CapturedX509Certificate, InMemorySigningKeyPair), Error> {
let key_pair = InMemorySigningKeyPair::generate_random(key_algorithm)?;
let cert = self.create_with_key_pair(&key_pair)?;
Ok((cert, key_pair))
}
/// Create a new certificate signing request (CSR).
///
/// The CSR is derived according to the process defined in RFC 2986 Section 3.
/// Essentially, we collect metadata about the request, sign that metadata using
/// a provided signing/private key, then attach the signature to form a complete
/// certification request.
pub fn create_certificate_signing_request(
&self,
signer: &dyn KeyInfoSigner,
) -> Result<rfc2986::CertificationRequest, Error> {
let info = rfc2986::CertificationRequestInfo {
version: rfc2986::Version::V1,
subject: self.subject.clone(),
subject_public_key_info: rfc5280::SubjectPublicKeyInfo {
algorithm: signer
.key_algorithm()
.ok_or_else(|| {
Error::UnknownKeyAlgorithm(
"OID not available due to API limitations".into(),
)
})?
.into(),
subject_public_key: BitString::new(0, signer.public_key_data()),
},
attributes: self.csr_attributes.clone(),
};
// The signature is produced over the DER encoding of CertificationRequestInfo
// per RFC 2986 Section 4.2.
let mut info_der = vec![];
info.write_encoded(Mode::Der, &mut info_der)?;
let signature = signer.try_sign(&info_der)?;
let signature_algorithm = signer.signature_algorithm()?;
let request = rfc2986::CertificationRequest {
certificate_request_info: info,
signature_algorithm: signature_algorithm.into(),
signature: BitString::new(0, signature.into()),
};
Ok(request)
}
}
#[cfg(test)]
mod test {
use {
super::*,
crate::{EcdsaCurve, X509CertificateError},
};
#[test]
fn builder_ed25519_default() {
let builder = X509CertificateBuilder::default();
builder
.create_with_random_keypair(KeyAlgorithm::Ed25519)
.unwrap();
}
#[test]
fn build_ecdsa_default() {
for curve in EcdsaCurve::all() {
let key_algorithm = KeyAlgorithm::Ecdsa(*curve);
let builder = X509CertificateBuilder::default();
builder.create_with_random_keypair(key_algorithm).unwrap();
}
}
#[test]
fn build_subject_populate() {
let mut builder = X509CertificateBuilder::default();
builder
.subject()
.append_common_name_utf8_string("My Name")
.unwrap();
builder
.subject()
.append_country_utf8_string("Wakanda")
.unwrap();
builder
.create_with_random_keypair(KeyAlgorithm::Ed25519)
.unwrap();
}
#[test]
fn builder_csr_ecdsa() -> Result<(), Error> {
for curve in EcdsaCurve::all() {
let key_algorithm = KeyAlgorithm::Ecdsa(*curve);
let key = InMemorySigningKeyPair::generate_random(key_algorithm)?;
let builder = X509CertificateBuilder::default();
let csr = builder.create_certificate_signing_request(&key)?;
assert_eq!(
csr.certificate_request_info
.subject_public_key_info
.algorithm,
key_algorithm.into()
);
}
Ok(())
}
#[test]
fn ecdsa_p256_sha256_self_signed() {
let der = include_bytes!("testdata/ecdsa-p256-sha256-self-signed.cer");
let cert = CapturedX509Certificate::from_der(der.to_vec()).unwrap();
cert.verify_signed_by_certificate(&cert).unwrap();
cert.to_public_key_der().unwrap();
}
#[test]
fn ecdsa_p384_sha256_self_signed() {
let der = include_bytes!("testdata/ecdsa-p384-sha256-self-signed.cer");
let cert = CapturedX509Certificate::from_der(der.to_vec()).unwrap();
cert.verify_signed_by_certificate(&cert).unwrap();
cert.to_public_key_der().unwrap();
}
#[test]
fn ecdsa_p512_sha256_self_signed() {
let der = include_bytes!("testdata/ecdsa-p512-sha256-self-signed.cer");
// We can parse this. But we don't support secp512 elliptic curves because ring
// doesn't support it.
let cert = CapturedX509Certificate::from_der(der.to_vec()).unwrap();
cert.to_public_key_der().unwrap();
assert!(matches!(
cert.verify_signed_by_certificate(&cert),
Err(Error::UnknownEllipticCurve(_))
));
}
#[test]
fn ecdsa_prime256v1_cert_validation() -> Result<(), X509CertificateError> {
let root = include_bytes!("testdata/ecdsa-prime256v1-root.der");
let signed = include_bytes!("testdata/ecdsa-prime256v1-signed.der");
let root = CapturedX509Certificate::from_der(root.as_ref())?;
let signed = CapturedX509Certificate::from_der(signed.as_ref())?;
root.verify_signed_by_certificate(&root)?;
signed.verify_signed_by_certificate(&root)?;
Ok(())
}
}