772 lines
24 KiB
Go
772 lines
24 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package ocsp parses OCSP responses as specified in RFC 2560. OCSP responses
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// are signed messages attesting to the validity of a certificate for a small
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// period of time. This is used to manage revocation for X.509 certificates.
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package ocsp // import "golang.org/x/crypto/ocsp"
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import (
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"crypto"
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"crypto/ecdsa"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/rsa"
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_ "crypto/sha1"
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_ "crypto/sha256"
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_ "crypto/sha512"
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"crypto/x509"
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"crypto/x509/pkix"
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"encoding/asn1"
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"errors"
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"fmt"
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"math/big"
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"strconv"
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"time"
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)
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var idPKIXOCSPBasic = asn1.ObjectIdentifier([]int{1, 3, 6, 1, 5, 5, 7, 48, 1, 1})
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// ResponseStatus contains the result of an OCSP request. See
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// https://tools.ietf.org/html/rfc6960#section-2.3
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type ResponseStatus int
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const (
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Success ResponseStatus = 0
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Malformed ResponseStatus = 1
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InternalError ResponseStatus = 2
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TryLater ResponseStatus = 3
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// Status code four is unused in OCSP. See
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// https://tools.ietf.org/html/rfc6960#section-4.2.1
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SignatureRequired ResponseStatus = 5
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Unauthorized ResponseStatus = 6
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)
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func (r ResponseStatus) String() string {
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switch r {
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case Success:
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return "success"
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case Malformed:
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return "malformed"
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case InternalError:
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return "internal error"
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case TryLater:
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return "try later"
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case SignatureRequired:
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return "signature required"
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case Unauthorized:
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return "unauthorized"
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default:
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return "unknown OCSP status: " + strconv.Itoa(int(r))
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}
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}
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// ResponseError is an error that may be returned by ParseResponse to indicate
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// that the response itself is an error, not just that its indicating that a
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// certificate is revoked, unknown, etc.
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type ResponseError struct {
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Status ResponseStatus
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}
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func (r ResponseError) Error() string {
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return "ocsp: error from server: " + r.Status.String()
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}
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// These are internal structures that reflect the ASN.1 structure of an OCSP
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// response. See RFC 2560, section 4.2.
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type certID struct {
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HashAlgorithm pkix.AlgorithmIdentifier
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NameHash []byte
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IssuerKeyHash []byte
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SerialNumber *big.Int
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}
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// https://tools.ietf.org/html/rfc2560#section-4.1.1
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type ocspRequest struct {
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TBSRequest tbsRequest
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}
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type tbsRequest struct {
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Version int `asn1:"explicit,tag:0,default:0,optional"`
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RequestorName pkix.RDNSequence `asn1:"explicit,tag:1,optional"`
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RequestList []request
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}
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type request struct {
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Cert certID
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}
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type responseASN1 struct {
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Status asn1.Enumerated
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Response responseBytes `asn1:"explicit,tag:0,optional"`
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}
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type responseBytes struct {
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ResponseType asn1.ObjectIdentifier
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Response []byte
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}
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type basicResponse struct {
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TBSResponseData responseData
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SignatureAlgorithm pkix.AlgorithmIdentifier
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Signature asn1.BitString
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Certificates []asn1.RawValue `asn1:"explicit,tag:0,optional"`
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}
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type responseData struct {
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Raw asn1.RawContent
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Version int `asn1:"optional,default:0,explicit,tag:0"`
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RawResponderID asn1.RawValue
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ProducedAt time.Time `asn1:"generalized"`
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Responses []singleResponse
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}
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type singleResponse struct {
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CertID certID
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Good asn1.Flag `asn1:"tag:0,optional"`
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Revoked revokedInfo `asn1:"tag:1,optional"`
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Unknown asn1.Flag `asn1:"tag:2,optional"`
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ThisUpdate time.Time `asn1:"generalized"`
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NextUpdate time.Time `asn1:"generalized,explicit,tag:0,optional"`
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SingleExtensions []pkix.Extension `asn1:"explicit,tag:1,optional"`
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}
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type revokedInfo struct {
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RevocationTime time.Time `asn1:"generalized"`
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Reason asn1.Enumerated `asn1:"explicit,tag:0,optional"`
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}
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var (
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oidSignatureMD2WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 2}
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oidSignatureMD5WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 4}
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oidSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}
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oidSignatureSHA256WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}
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oidSignatureSHA384WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12}
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oidSignatureSHA512WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13}
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oidSignatureDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3}
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oidSignatureDSAWithSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 2}
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oidSignatureECDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}
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oidSignatureECDSAWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}
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oidSignatureECDSAWithSHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3}
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oidSignatureECDSAWithSHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4}
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)
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var hashOIDs = map[crypto.Hash]asn1.ObjectIdentifier{
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crypto.SHA1: asn1.ObjectIdentifier([]int{1, 3, 14, 3, 2, 26}),
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crypto.SHA256: asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 1}),
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crypto.SHA384: asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 2}),
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crypto.SHA512: asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 3}),
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}
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// TODO(rlb): This is also from crypto/x509, so same comment as AGL's below
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var signatureAlgorithmDetails = []struct {
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algo x509.SignatureAlgorithm
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oid asn1.ObjectIdentifier
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pubKeyAlgo x509.PublicKeyAlgorithm
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hash crypto.Hash
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}{
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{x509.MD2WithRSA, oidSignatureMD2WithRSA, x509.RSA, crypto.Hash(0) /* no value for MD2 */},
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{x509.MD5WithRSA, oidSignatureMD5WithRSA, x509.RSA, crypto.MD5},
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{x509.SHA1WithRSA, oidSignatureSHA1WithRSA, x509.RSA, crypto.SHA1},
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{x509.SHA256WithRSA, oidSignatureSHA256WithRSA, x509.RSA, crypto.SHA256},
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{x509.SHA384WithRSA, oidSignatureSHA384WithRSA, x509.RSA, crypto.SHA384},
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{x509.SHA512WithRSA, oidSignatureSHA512WithRSA, x509.RSA, crypto.SHA512},
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{x509.DSAWithSHA1, oidSignatureDSAWithSHA1, x509.DSA, crypto.SHA1},
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{x509.DSAWithSHA256, oidSignatureDSAWithSHA256, x509.DSA, crypto.SHA256},
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{x509.ECDSAWithSHA1, oidSignatureECDSAWithSHA1, x509.ECDSA, crypto.SHA1},
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{x509.ECDSAWithSHA256, oidSignatureECDSAWithSHA256, x509.ECDSA, crypto.SHA256},
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{x509.ECDSAWithSHA384, oidSignatureECDSAWithSHA384, x509.ECDSA, crypto.SHA384},
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{x509.ECDSAWithSHA512, oidSignatureECDSAWithSHA512, x509.ECDSA, crypto.SHA512},
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}
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// TODO(rlb): This is also from crypto/x509, so same comment as AGL's below
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func signingParamsForPublicKey(pub interface{}, requestedSigAlgo x509.SignatureAlgorithm) (hashFunc crypto.Hash, sigAlgo pkix.AlgorithmIdentifier, err error) {
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var pubType x509.PublicKeyAlgorithm
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switch pub := pub.(type) {
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case *rsa.PublicKey:
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pubType = x509.RSA
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hashFunc = crypto.SHA256
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sigAlgo.Algorithm = oidSignatureSHA256WithRSA
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sigAlgo.Parameters = asn1.RawValue{
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Tag: 5,
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}
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case *ecdsa.PublicKey:
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pubType = x509.ECDSA
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switch pub.Curve {
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case elliptic.P224(), elliptic.P256():
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hashFunc = crypto.SHA256
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sigAlgo.Algorithm = oidSignatureECDSAWithSHA256
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case elliptic.P384():
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hashFunc = crypto.SHA384
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sigAlgo.Algorithm = oidSignatureECDSAWithSHA384
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case elliptic.P521():
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hashFunc = crypto.SHA512
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sigAlgo.Algorithm = oidSignatureECDSAWithSHA512
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default:
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err = errors.New("x509: unknown elliptic curve")
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}
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default:
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err = errors.New("x509: only RSA and ECDSA keys supported")
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}
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if err != nil {
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return
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}
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if requestedSigAlgo == 0 {
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return
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}
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found := false
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for _, details := range signatureAlgorithmDetails {
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if details.algo == requestedSigAlgo {
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if details.pubKeyAlgo != pubType {
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err = errors.New("x509: requested SignatureAlgorithm does not match private key type")
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return
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}
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sigAlgo.Algorithm, hashFunc = details.oid, details.hash
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if hashFunc == 0 {
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err = errors.New("x509: cannot sign with hash function requested")
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return
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}
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found = true
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break
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}
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}
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if !found {
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err = errors.New("x509: unknown SignatureAlgorithm")
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}
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return
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}
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// TODO(agl): this is taken from crypto/x509 and so should probably be exported
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// from crypto/x509 or crypto/x509/pkix.
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func getSignatureAlgorithmFromOID(oid asn1.ObjectIdentifier) x509.SignatureAlgorithm {
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for _, details := range signatureAlgorithmDetails {
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if oid.Equal(details.oid) {
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return details.algo
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}
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}
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return x509.UnknownSignatureAlgorithm
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}
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// TODO(rlb): This is not taken from crypto/x509, but it's of the same general form.
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func getHashAlgorithmFromOID(target asn1.ObjectIdentifier) crypto.Hash {
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for hash, oid := range hashOIDs {
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if oid.Equal(target) {
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return hash
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}
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}
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return crypto.Hash(0)
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}
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func getOIDFromHashAlgorithm(target crypto.Hash) asn1.ObjectIdentifier {
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for hash, oid := range hashOIDs {
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if hash == target {
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return oid
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}
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}
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return nil
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}
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// This is the exposed reflection of the internal OCSP structures.
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// The status values that can be expressed in OCSP. See RFC 6960.
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const (
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// Good means that the certificate is valid.
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Good = iota
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// Revoked means that the certificate has been deliberately revoked.
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Revoked
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// Unknown means that the OCSP responder doesn't know about the certificate.
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Unknown
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// ServerFailed is unused and was never used (see
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// https://go-review.googlesource.com/#/c/18944). ParseResponse will
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// return a ResponseError when an error response is parsed.
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ServerFailed
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)
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// The enumerated reasons for revoking a certificate. See RFC 5280.
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const (
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Unspecified = iota
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KeyCompromise = iota
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CACompromise = iota
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AffiliationChanged = iota
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Superseded = iota
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CessationOfOperation = iota
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CertificateHold = iota
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_ = iota
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RemoveFromCRL = iota
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PrivilegeWithdrawn = iota
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AACompromise = iota
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)
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// Request represents an OCSP request. See RFC 6960.
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type Request struct {
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HashAlgorithm crypto.Hash
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IssuerNameHash []byte
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IssuerKeyHash []byte
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SerialNumber *big.Int
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}
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// Marshal marshals the OCSP request to ASN.1 DER encoded form.
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func (req *Request) Marshal() ([]byte, error) {
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hashAlg := getOIDFromHashAlgorithm(req.HashAlgorithm)
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if hashAlg == nil {
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return nil, errors.New("Unknown hash algorithm")
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}
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return asn1.Marshal(ocspRequest{
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tbsRequest{
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Version: 0,
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RequestList: []request{
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{
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Cert: certID{
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pkix.AlgorithmIdentifier{
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Algorithm: hashAlg,
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Parameters: asn1.RawValue{Tag: 5 /* ASN.1 NULL */},
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},
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req.IssuerNameHash,
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req.IssuerKeyHash,
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req.SerialNumber,
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},
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},
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},
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},
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})
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}
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// Response represents an OCSP response containing a single SingleResponse. See
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// RFC 6960.
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type Response struct {
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// Status is one of {Good, Revoked, Unknown}
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Status int
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SerialNumber *big.Int
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ProducedAt, ThisUpdate, NextUpdate, RevokedAt time.Time
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RevocationReason int
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Certificate *x509.Certificate
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// TBSResponseData contains the raw bytes of the signed response. If
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// Certificate is nil then this can be used to verify Signature.
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TBSResponseData []byte
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Signature []byte
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SignatureAlgorithm x509.SignatureAlgorithm
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// IssuerHash is the hash used to compute the IssuerNameHash and IssuerKeyHash.
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// Valid values are crypto.SHA1, crypto.SHA256, crypto.SHA384, and crypto.SHA512.
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// If zero, the default is crypto.SHA1.
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IssuerHash crypto.Hash
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// RawResponderName optionally contains the DER-encoded subject of the
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// responder certificate. Exactly one of RawResponderName and
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// ResponderKeyHash is set.
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RawResponderName []byte
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// ResponderKeyHash optionally contains the SHA-1 hash of the
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// responder's public key. Exactly one of RawResponderName and
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// ResponderKeyHash is set.
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ResponderKeyHash []byte
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// Extensions contains raw X.509 extensions from the singleExtensions field
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// of the OCSP response. When parsing certificates, this can be used to
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// extract non-critical extensions that are not parsed by this package. When
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// marshaling OCSP responses, the Extensions field is ignored, see
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// ExtraExtensions.
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Extensions []pkix.Extension
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// ExtraExtensions contains extensions to be copied, raw, into any marshaled
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// OCSP response (in the singleExtensions field). Values override any
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// extensions that would otherwise be produced based on the other fields. The
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// ExtraExtensions field is not populated when parsing certificates, see
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// Extensions.
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ExtraExtensions []pkix.Extension
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}
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// These are pre-serialized error responses for the various non-success codes
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// defined by OCSP. The Unauthorized code in particular can be used by an OCSP
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// responder that supports only pre-signed responses as a response to requests
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// for certificates with unknown status. See RFC 5019.
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var (
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MalformedRequestErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x01}
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InternalErrorErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x02}
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TryLaterErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x03}
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SigRequredErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x05}
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UnauthorizedErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x06}
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)
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// CheckSignatureFrom checks that the signature in resp is a valid signature
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// from issuer. This should only be used if resp.Certificate is nil. Otherwise,
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// the OCSP response contained an intermediate certificate that created the
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// signature. That signature is checked by ParseResponse and only
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// resp.Certificate remains to be validated.
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func (resp *Response) CheckSignatureFrom(issuer *x509.Certificate) error {
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return issuer.CheckSignature(resp.SignatureAlgorithm, resp.TBSResponseData, resp.Signature)
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}
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// ParseError results from an invalid OCSP response.
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type ParseError string
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func (p ParseError) Error() string {
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return string(p)
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}
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// ParseRequest parses an OCSP request in DER form. It only supports
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// requests for a single certificate. Signed requests are not supported.
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// If a request includes a signature, it will result in a ParseError.
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func ParseRequest(bytes []byte) (*Request, error) {
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var req ocspRequest
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rest, err := asn1.Unmarshal(bytes, &req)
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if err != nil {
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return nil, err
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}
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if len(rest) > 0 {
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return nil, ParseError("trailing data in OCSP request")
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}
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if len(req.TBSRequest.RequestList) == 0 {
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return nil, ParseError("OCSP request contains no request body")
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}
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innerRequest := req.TBSRequest.RequestList[0]
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hashFunc := getHashAlgorithmFromOID(innerRequest.Cert.HashAlgorithm.Algorithm)
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if hashFunc == crypto.Hash(0) {
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return nil, ParseError("OCSP request uses unknown hash function")
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}
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return &Request{
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HashAlgorithm: hashFunc,
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IssuerNameHash: innerRequest.Cert.NameHash,
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IssuerKeyHash: innerRequest.Cert.IssuerKeyHash,
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SerialNumber: innerRequest.Cert.SerialNumber,
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}, nil
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}
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// ParseResponse parses an OCSP response in DER form. It only supports
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// responses for a single certificate. If the response contains a certificate
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// then the signature over the response is checked. If issuer is not nil then
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// it will be used to validate the signature or embedded certificate.
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//
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// Invalid signatures or parse failures will result in a ParseError. Error
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// responses will result in a ResponseError.
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func ParseResponse(bytes []byte, issuer *x509.Certificate) (*Response, error) {
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return ParseResponseForCert(bytes, nil, issuer)
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}
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// ParseResponseForCert parses an OCSP response in DER form and searches for a
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// Response relating to cert. If such a Response is found and the OCSP response
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// contains a certificate then the signature over the response is checked. If
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// issuer is not nil then it will be used to validate the signature or embedded
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// certificate.
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//
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// Invalid signatures or parse failures will result in a ParseError. Error
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// responses will result in a ResponseError.
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func ParseResponseForCert(bytes []byte, cert, issuer *x509.Certificate) (*Response, error) {
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var resp responseASN1
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rest, err := asn1.Unmarshal(bytes, &resp)
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if err != nil {
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return nil, err
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}
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if len(rest) > 0 {
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return nil, ParseError("trailing data in OCSP response")
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}
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if status := ResponseStatus(resp.Status); status != Success {
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return nil, ResponseError{status}
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}
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if !resp.Response.ResponseType.Equal(idPKIXOCSPBasic) {
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return nil, ParseError("bad OCSP response type")
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}
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var basicResp basicResponse
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rest, err = asn1.Unmarshal(resp.Response.Response, &basicResp)
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if err != nil {
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return nil, err
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}
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|
if len(basicResp.Certificates) > 1 {
|
|
return nil, ParseError("OCSP response contains bad number of certificates")
|
|
}
|
|
|
|
if n := len(basicResp.TBSResponseData.Responses); n == 0 || cert == nil && n > 1 {
|
|
return nil, ParseError("OCSP response contains bad number of responses")
|
|
}
|
|
|
|
ret := &Response{
|
|
TBSResponseData: basicResp.TBSResponseData.Raw,
|
|
Signature: basicResp.Signature.RightAlign(),
|
|
SignatureAlgorithm: getSignatureAlgorithmFromOID(basicResp.SignatureAlgorithm.Algorithm),
|
|
}
|
|
|
|
// Handle the ResponderID CHOICE tag. ResponderID can be flattened into
|
|
// TBSResponseData once https://go-review.googlesource.com/34503 has been
|
|
// released.
|
|
rawResponderID := basicResp.TBSResponseData.RawResponderID
|
|
switch rawResponderID.Tag {
|
|
case 1: // Name
|
|
var rdn pkix.RDNSequence
|
|
if rest, err := asn1.Unmarshal(rawResponderID.Bytes, &rdn); err != nil || len(rest) != 0 {
|
|
return nil, ParseError("invalid responder name")
|
|
}
|
|
ret.RawResponderName = rawResponderID.Bytes
|
|
case 2: // KeyHash
|
|
if rest, err := asn1.Unmarshal(rawResponderID.Bytes, &ret.ResponderKeyHash); err != nil || len(rest) != 0 {
|
|
return nil, ParseError("invalid responder key hash")
|
|
}
|
|
default:
|
|
return nil, ParseError("invalid responder id tag")
|
|
}
|
|
|
|
if len(basicResp.Certificates) > 0 {
|
|
ret.Certificate, err = x509.ParseCertificate(basicResp.Certificates[0].FullBytes)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if err := ret.CheckSignatureFrom(ret.Certificate); err != nil {
|
|
return nil, ParseError("bad signature on embedded certificate: " + err.Error())
|
|
}
|
|
|
|
if issuer != nil {
|
|
if err := issuer.CheckSignature(ret.Certificate.SignatureAlgorithm, ret.Certificate.RawTBSCertificate, ret.Certificate.Signature); err != nil {
|
|
return nil, ParseError("bad OCSP signature: " + err.Error())
|
|
}
|
|
}
|
|
} else if issuer != nil {
|
|
if err := ret.CheckSignatureFrom(issuer); err != nil {
|
|
return nil, ParseError("bad OCSP signature: " + err.Error())
|
|
}
|
|
}
|
|
|
|
var r singleResponse
|
|
for _, resp := range basicResp.TBSResponseData.Responses {
|
|
if cert == nil || cert.SerialNumber.Cmp(resp.CertID.SerialNumber) == 0 {
|
|
r = resp
|
|
break
|
|
}
|
|
}
|
|
|
|
for _, ext := range r.SingleExtensions {
|
|
if ext.Critical {
|
|
return nil, ParseError("unsupported critical extension")
|
|
}
|
|
}
|
|
ret.Extensions = r.SingleExtensions
|
|
|
|
ret.SerialNumber = r.CertID.SerialNumber
|
|
|
|
for h, oid := range hashOIDs {
|
|
if r.CertID.HashAlgorithm.Algorithm.Equal(oid) {
|
|
ret.IssuerHash = h
|
|
break
|
|
}
|
|
}
|
|
if ret.IssuerHash == 0 {
|
|
return nil, ParseError("unsupported issuer hash algorithm")
|
|
}
|
|
|
|
switch {
|
|
case bool(r.Good):
|
|
ret.Status = Good
|
|
case bool(r.Unknown):
|
|
ret.Status = Unknown
|
|
default:
|
|
ret.Status = Revoked
|
|
ret.RevokedAt = r.Revoked.RevocationTime
|
|
ret.RevocationReason = int(r.Revoked.Reason)
|
|
}
|
|
|
|
ret.ProducedAt = basicResp.TBSResponseData.ProducedAt
|
|
ret.ThisUpdate = r.ThisUpdate
|
|
ret.NextUpdate = r.NextUpdate
|
|
|
|
return ret, nil
|
|
}
|
|
|
|
// RequestOptions contains options for constructing OCSP requests.
|
|
type RequestOptions struct {
|
|
// Hash contains the hash function that should be used when
|
|
// constructing the OCSP request. If zero, SHA-1 will be used.
|
|
Hash crypto.Hash
|
|
}
|
|
|
|
func (opts *RequestOptions) hash() crypto.Hash {
|
|
if opts == nil || opts.Hash == 0 {
|
|
// SHA-1 is nearly universally used in OCSP.
|
|
return crypto.SHA1
|
|
}
|
|
return opts.Hash
|
|
}
|
|
|
|
// CreateRequest returns a DER-encoded, OCSP request for the status of cert. If
|
|
// opts is nil then sensible defaults are used.
|
|
func CreateRequest(cert, issuer *x509.Certificate, opts *RequestOptions) ([]byte, error) {
|
|
hashFunc := opts.hash()
|
|
|
|
// OCSP seems to be the only place where these raw hash identifiers are
|
|
// used. I took the following from
|
|
// http://msdn.microsoft.com/en-us/library/ff635603.aspx
|
|
_, ok := hashOIDs[hashFunc]
|
|
if !ok {
|
|
return nil, x509.ErrUnsupportedAlgorithm
|
|
}
|
|
|
|
if !hashFunc.Available() {
|
|
return nil, x509.ErrUnsupportedAlgorithm
|
|
}
|
|
h := opts.hash().New()
|
|
|
|
var publicKeyInfo struct {
|
|
Algorithm pkix.AlgorithmIdentifier
|
|
PublicKey asn1.BitString
|
|
}
|
|
if _, err := asn1.Unmarshal(issuer.RawSubjectPublicKeyInfo, &publicKeyInfo); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
h.Write(publicKeyInfo.PublicKey.RightAlign())
|
|
issuerKeyHash := h.Sum(nil)
|
|
|
|
h.Reset()
|
|
h.Write(issuer.RawSubject)
|
|
issuerNameHash := h.Sum(nil)
|
|
|
|
req := &Request{
|
|
HashAlgorithm: hashFunc,
|
|
IssuerNameHash: issuerNameHash,
|
|
IssuerKeyHash: issuerKeyHash,
|
|
SerialNumber: cert.SerialNumber,
|
|
}
|
|
return req.Marshal()
|
|
}
|
|
|
|
// CreateResponse returns a DER-encoded OCSP response with the specified contents.
|
|
// The fields in the response are populated as follows:
|
|
//
|
|
// The responder cert is used to populate the responder's name field, and the
|
|
// certificate itself is provided alongside the OCSP response signature.
|
|
//
|
|
// The issuer cert is used to puplate the IssuerNameHash and IssuerKeyHash fields.
|
|
//
|
|
// The template is used to populate the SerialNumber, RevocationStatus, RevokedAt,
|
|
// RevocationReason, ThisUpdate, and NextUpdate fields.
|
|
//
|
|
// If template.IssuerHash is not set, SHA1 will be used.
|
|
//
|
|
// The ProducedAt date is automatically set to the current date, to the nearest minute.
|
|
func CreateResponse(issuer, responderCert *x509.Certificate, template Response, priv crypto.Signer) ([]byte, error) {
|
|
var publicKeyInfo struct {
|
|
Algorithm pkix.AlgorithmIdentifier
|
|
PublicKey asn1.BitString
|
|
}
|
|
if _, err := asn1.Unmarshal(issuer.RawSubjectPublicKeyInfo, &publicKeyInfo); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if template.IssuerHash == 0 {
|
|
template.IssuerHash = crypto.SHA1
|
|
}
|
|
hashOID := getOIDFromHashAlgorithm(template.IssuerHash)
|
|
if hashOID == nil {
|
|
return nil, errors.New("unsupported issuer hash algorithm")
|
|
}
|
|
|
|
if !template.IssuerHash.Available() {
|
|
return nil, fmt.Errorf("issuer hash algorithm %v not linked into binary", template.IssuerHash)
|
|
}
|
|
h := template.IssuerHash.New()
|
|
h.Write(publicKeyInfo.PublicKey.RightAlign())
|
|
issuerKeyHash := h.Sum(nil)
|
|
|
|
h.Reset()
|
|
h.Write(issuer.RawSubject)
|
|
issuerNameHash := h.Sum(nil)
|
|
|
|
innerResponse := singleResponse{
|
|
CertID: certID{
|
|
HashAlgorithm: pkix.AlgorithmIdentifier{
|
|
Algorithm: hashOID,
|
|
Parameters: asn1.RawValue{Tag: 5 /* ASN.1 NULL */},
|
|
},
|
|
NameHash: issuerNameHash,
|
|
IssuerKeyHash: issuerKeyHash,
|
|
SerialNumber: template.SerialNumber,
|
|
},
|
|
ThisUpdate: template.ThisUpdate.UTC(),
|
|
NextUpdate: template.NextUpdate.UTC(),
|
|
SingleExtensions: template.ExtraExtensions,
|
|
}
|
|
|
|
switch template.Status {
|
|
case Good:
|
|
innerResponse.Good = true
|
|
case Unknown:
|
|
innerResponse.Unknown = true
|
|
case Revoked:
|
|
innerResponse.Revoked = revokedInfo{
|
|
RevocationTime: template.RevokedAt.UTC(),
|
|
Reason: asn1.Enumerated(template.RevocationReason),
|
|
}
|
|
}
|
|
|
|
rawResponderID := asn1.RawValue{
|
|
Class: 2, // context-specific
|
|
Tag: 1, // Name (explicit tag)
|
|
IsCompound: true,
|
|
Bytes: responderCert.RawSubject,
|
|
}
|
|
tbsResponseData := responseData{
|
|
Version: 0,
|
|
RawResponderID: rawResponderID,
|
|
ProducedAt: time.Now().Truncate(time.Minute).UTC(),
|
|
Responses: []singleResponse{innerResponse},
|
|
}
|
|
|
|
tbsResponseDataDER, err := asn1.Marshal(tbsResponseData)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(priv.Public(), template.SignatureAlgorithm)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
responseHash := hashFunc.New()
|
|
responseHash.Write(tbsResponseDataDER)
|
|
signature, err := priv.Sign(rand.Reader, responseHash.Sum(nil), hashFunc)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
response := basicResponse{
|
|
TBSResponseData: tbsResponseData,
|
|
SignatureAlgorithm: signatureAlgorithm,
|
|
Signature: asn1.BitString{
|
|
Bytes: signature,
|
|
BitLength: 8 * len(signature),
|
|
},
|
|
}
|
|
if template.Certificate != nil {
|
|
response.Certificates = []asn1.RawValue{
|
|
asn1.RawValue{FullBytes: template.Certificate.Raw},
|
|
}
|
|
}
|
|
responseDER, err := asn1.Marshal(response)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return asn1.Marshal(responseASN1{
|
|
Status: asn1.Enumerated(Success),
|
|
Response: responseBytes{
|
|
ResponseType: idPKIXOCSPBasic,
|
|
Response: responseDER,
|
|
},
|
|
})
|
|
}
|