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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Buffers;
using System.Diagnostics;
using System.Formats.Asn1;
using System.Security.Cryptography.Asn1;
using System.Security.Cryptography.X509Certificates.Asn1;
namespace System.Security.Cryptography.X509Certificates
{
public sealed partial class CertificateRequest
{
private const CertificateRequestLoadOptions AllOptions =
CertificateRequestLoadOptions.SkipSignatureValidation |
CertificateRequestLoadOptions.UnsafeLoadCertificateExtensions;
public static CertificateRequest LoadSigningRequestPem(
string pkcs10Pem,
HashAlgorithmName signerHashAlgorithm,
CertificateRequestLoadOptions options = CertificateRequestLoadOptions.Default,
RSASignaturePadding? signerSignaturePadding = null)
{
ArgumentNullException.ThrowIfNull(pkcs10Pem);
return LoadSigningRequestPem(
pkcs10Pem.AsSpan(),
signerHashAlgorithm,
options,
signerSignaturePadding);
}
public static CertificateRequest LoadSigningRequestPem(
ReadOnlySpan<char> pkcs10Pem,
HashAlgorithmName signerHashAlgorithm,
CertificateRequestLoadOptions options = CertificateRequestLoadOptions.Default,
RSASignaturePadding? signerSignaturePadding = null)
{
ArgumentException.ThrowIfNullOrEmpty(signerHashAlgorithm.Name, nameof(signerHashAlgorithm));
if ((options & ~AllOptions) != 0)
{
throw new ArgumentOutOfRangeException(nameof(options), options, SR.Argument_InvalidFlag);
}
foreach ((ReadOnlySpan<char> contents, PemFields fields) in PemEnumerator.Utf16(pkcs10Pem))
{
if (contents[fields.Label].SequenceEqual(PemLabels.Pkcs10CertificateRequest))
{
byte[] rented = ArrayPool<byte>.Shared.Rent(fields.DecodedDataLength);
if (!Convert.TryFromBase64Chars(contents[fields.Base64Data], rented, out int bytesWritten) ||
bytesWritten != fields.DecodedDataLength)
{
Debug.Fail("Base64Decode failed, but PemEncoding said it was legal");
throw new UnreachableException();
}
try
{
return LoadSigningRequest(
rented.AsSpan(0, bytesWritten),
permitTrailingData: false,
signerHashAlgorithm,
out _,
options,
signerSignaturePadding);
}
finally
{
ArrayPool<byte>.Shared.Return(rented);
}
}
}
throw new CryptographicException(
SR.Format(SR.Cryptography_NoPemOfLabel, PemLabels.Pkcs10CertificateRequest));
}
public static CertificateRequest LoadSigningRequest(
byte[] pkcs10,
HashAlgorithmName signerHashAlgorithm,
CertificateRequestLoadOptions options = CertificateRequestLoadOptions.Default,
RSASignaturePadding? signerSignaturePadding = null)
{
ArgumentNullException.ThrowIfNull(pkcs10);
return LoadSigningRequest(
pkcs10,
permitTrailingData: false,
signerHashAlgorithm,
out _,
options,
signerSignaturePadding);
}
public static CertificateRequest LoadSigningRequest(
ReadOnlySpan<byte> pkcs10,
HashAlgorithmName signerHashAlgorithm,
out int bytesConsumed,
CertificateRequestLoadOptions options = CertificateRequestLoadOptions.Default,
RSASignaturePadding? signerSignaturePadding = null)
{
return LoadSigningRequest(
pkcs10,
permitTrailingData: true,
signerHashAlgorithm,
out bytesConsumed,
options,
signerSignaturePadding);
}
private static unsafe CertificateRequest LoadSigningRequest(
ReadOnlySpan<byte> pkcs10,
bool permitTrailingData,
HashAlgorithmName signerHashAlgorithm,
out int bytesConsumed,
CertificateRequestLoadOptions options,
RSASignaturePadding? signerSignaturePadding)
{
ArgumentException.ThrowIfNullOrEmpty(signerHashAlgorithm.Name, nameof(signerHashAlgorithm));
if ((options & ~AllOptions) != 0)
{
throw new ArgumentOutOfRangeException(nameof(options), options, SR.Argument_InvalidFlag);
}
bool skipSignatureValidation =
(options & CertificateRequestLoadOptions.SkipSignatureValidation) != 0;
bool unsafeLoadCertificateExtensions =
(options & CertificateRequestLoadOptions.UnsafeLoadCertificateExtensions) != 0;
try
{
AsnValueReader outer = new AsnValueReader(pkcs10, AsnEncodingRules.DER);
int encodedLength = outer.PeekEncodedValue().Length;
AsnValueReader pkcs10Asn = outer.ReadSequence();
CertificateRequest req;
if (!permitTrailingData)
{
outer.ThrowIfNotEmpty();
}
fixed (byte* p10ptr = pkcs10)
{
using (PointerMemoryManager<byte> manager = new PointerMemoryManager<byte>(p10ptr, encodedLength))
{
ReadOnlyMemory<byte> rebind = manager.Memory;
ReadOnlySpan<byte> encodedRequestInfo = pkcs10Asn.PeekEncodedValue();
CertificationRequestInfoAsn requestInfo;
AlgorithmIdentifierAsn algorithmIdentifier;
ReadOnlySpan<byte> signature;
int signatureUnusedBitCount;
CertificationRequestInfoAsn.Decode(ref pkcs10Asn, rebind, out requestInfo);
AlgorithmIdentifierAsn.Decode(ref pkcs10Asn, rebind, out algorithmIdentifier);
if (!pkcs10Asn.TryReadPrimitiveBitString(out signatureUnusedBitCount, out signature))
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding);
}
pkcs10Asn.ThrowIfNotEmpty();
if (requestInfo.Version < 0)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding);
}
// They haven't bumped from v0 to v1 as of 2022.
const int MaxSupportedVersion = 0;
if (requestInfo.Version != MaxSupportedVersion)
{
throw new CryptographicException(
SR.Format(
SR.Cryptography_CertReq_Load_VersionTooNew,
requestInfo.Version,
MaxSupportedVersion));
}
PublicKey publicKey = PublicKey.DecodeSubjectPublicKeyInfo(ref requestInfo.SubjectPublicKeyInfo);
if (!skipSignatureValidation)
{
// None of the supported signature algorithms support signatures that are not full bytes.
// So, shortcut the verification on the bit length
if (signatureUnusedBitCount != 0 ||
!VerifyX509Signature(encodedRequestInfo, signature, publicKey, algorithmIdentifier))
{
throw new CryptographicException(SR.Cryptography_CertReq_SignatureVerificationFailed);
}
}
X500DistinguishedName subject = new X500DistinguishedName(requestInfo.Subject.Span);
req = new CertificateRequest(
subject,
publicKey,
signerHashAlgorithm,
signerSignaturePadding);
if (requestInfo.Attributes is not null)
{
bool foundCertExt = false;
foreach (AttributeAsn attr in requestInfo.Attributes)
{
if (attr.AttrType == Oids.Pkcs9ExtensionRequest)
{
if (foundCertExt)
{
throw new CryptographicException(
SR.Cryptography_CertReq_Load_DuplicateExtensionRequests);
}
foundCertExt = true;
if (attr.AttrValues.Length != 1)
{
throw new CryptographicException(
SR.Cryptography_CertReq_Load_DuplicateExtensionRequests);
}
AsnValueReader extsReader = new AsnValueReader(
attr.AttrValues[0].Span,
AsnEncodingRules.DER);
AsnValueReader exts = extsReader.ReadSequence();
extsReader.ThrowIfNotEmpty();
// Minimum length is 1, so do..while
do
{
X509ExtensionAsn.Decode(ref exts, rebind, out X509ExtensionAsn extAsn);
if (unsafeLoadCertificateExtensions)
{
X509Extension ext = new X509Extension(
extAsn.ExtnId,
extAsn.ExtnValue.Span,
extAsn.Critical);
X509Extension? rich =
X509Certificate2.CreateCustomExtensionIfAny(extAsn.ExtnId);
if (rich is not null)
{
rich.CopyFrom(ext);
req.CertificateExtensions.Add(rich);
}
else
{
req.CertificateExtensions.Add(ext);
}
}
} while (exts.HasData);
}
else
{
if (attr.AttrValues.Length == 0)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding);
}
foreach (ReadOnlyMemory<byte> val in attr.AttrValues)
{
req.OtherRequestAttributes.Add(
new AsnEncodedData(attr.AttrType, val.Span));
}
}
}
}
}
}
bytesConsumed = encodedLength;
return req;
}
catch (AsnContentException e)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding, e);
}
}
private static bool VerifyX509Signature(
ReadOnlySpan<byte> toBeSigned,
ReadOnlySpan<byte> signature,
PublicKey publicKey,
AlgorithmIdentifierAsn algorithmIdentifier)
{
RSA? rsa = publicKey.GetRSAPublicKey();
ECDsa? ecdsa = publicKey.GetECDsaPublicKey();
try
{
HashAlgorithmName hashAlg;
if (algorithmIdentifier.Algorithm == Oids.RsaPss)
{
if (rsa is null || !algorithmIdentifier.Parameters.HasValue)
{
return false;
}
PssParamsAsn pssParams = PssParamsAsn.Decode(
algorithmIdentifier.Parameters.GetValueOrDefault(),
AsnEncodingRules.DER);
RSASignaturePadding padding = pssParams.GetSignaturePadding();
hashAlg = HashAlgorithmName.FromOid(pssParams.HashAlgorithm.Algorithm);
return rsa.VerifyData(
toBeSigned,
signature,
hashAlg,
padding);
}
switch (algorithmIdentifier.Algorithm)
{
case Oids.RsaPkcs1Sha256:
case Oids.ECDsaWithSha256:
hashAlg = HashAlgorithmName.SHA256;
break;
case Oids.RsaPkcs1Sha384:
case Oids.ECDsaWithSha384:
hashAlg = HashAlgorithmName.SHA384;
break;
case Oids.RsaPkcs1Sha512:
case Oids.ECDsaWithSha512:
hashAlg = HashAlgorithmName.SHA512;
break;
case Oids.RsaPkcs1Sha1:
case Oids.ECDsaWithSha1:
hashAlg = HashAlgorithmName.SHA1;
break;
default:
throw new NotSupportedException(
SR.Format(SR.Cryptography_UnknownKeyAlgorithm, algorithmIdentifier.Algorithm));
}
// All remaining supported algorithms have no defined parameters
if (!algorithmIdentifier.HasNullEquivalentParameters())
{
return false;
}
switch (algorithmIdentifier.Algorithm)
{
case Oids.RsaPkcs1Sha256:
case Oids.RsaPkcs1Sha384:
case Oids.RsaPkcs1Sha512:
case Oids.RsaPkcs1Sha1:
if (rsa is null)
{
return false;
}
return rsa.VerifyData(toBeSigned, signature, hashAlg, RSASignaturePadding.Pkcs1);
case Oids.ECDsaWithSha256:
case Oids.ECDsaWithSha384:
case Oids.ECDsaWithSha512:
case Oids.ECDsaWithSha1:
if (ecdsa is null)
{
return false;
}
return ecdsa.VerifyData(toBeSigned, signature, hashAlg, DSASignatureFormat.Rfc3279DerSequence);
default:
Debug.Fail(
$"Algorithm ID {algorithmIdentifier.Algorithm} was in the first switch, but not the second");
return false;
}
}
catch (AsnContentException)
{
return false;
}
catch (CryptographicException)
{
return false;
}
finally
{
rsa?.Dispose();
ecdsa?.Dispose();
}
}
}
}
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