diff options
Diffstat (limited to 'vendor/github.com/rsc/letsencrypt/vendor/golang.org/x/crypto/ocsp/ocsp.go')
| -rw-r--r-- | vendor/github.com/rsc/letsencrypt/vendor/golang.org/x/crypto/ocsp/ocsp.go | 778 |
1 files changed, 778 insertions, 0 deletions
diff --git a/vendor/github.com/rsc/letsencrypt/vendor/golang.org/x/crypto/ocsp/ocsp.go b/vendor/github.com/rsc/letsencrypt/vendor/golang.org/x/crypto/ocsp/ocsp.go new file mode 100644 index 000000000..6bd347e28 --- /dev/null +++ b/vendor/github.com/rsc/letsencrypt/vendor/golang.org/x/crypto/ocsp/ocsp.go @@ -0,0 +1,778 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package ocsp parses OCSP responses as specified in RFC 2560. OCSP responses +// are signed messages attesting to the validity of a certificate for a small +// period of time. This is used to manage revocation for X.509 certificates. +package ocsp // import "golang.org/x/crypto/ocsp" + +import ( + "crypto" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rand" + "crypto/rsa" + _ "crypto/sha1" + _ "crypto/sha256" + _ "crypto/sha512" + "crypto/x509" + "crypto/x509/pkix" + "encoding/asn1" + "errors" + "fmt" + "math/big" + "strconv" + "time" +) + +var idPKIXOCSPBasic = asn1.ObjectIdentifier([]int{1, 3, 6, 1, 5, 5, 7, 48, 1, 1}) + +// ResponseStatus contains the result of an OCSP request. See +// https://tools.ietf.org/html/rfc6960#section-2.3 +type ResponseStatus int + +const ( + Success ResponseStatus = 0 + Malformed ResponseStatus = 1 + InternalError ResponseStatus = 2 + TryLater ResponseStatus = 3 + // Status code four is unused in OCSP. See + // https://tools.ietf.org/html/rfc6960#section-4.2.1 + SignatureRequired ResponseStatus = 5 + Unauthorized ResponseStatus = 6 +) + +func (r ResponseStatus) String() string { + switch r { + case Success: + return "success" + case Malformed: + return "malformed" + case InternalError: + return "internal error" + case TryLater: + return "try later" + case SignatureRequired: + return "signature required" + case Unauthorized: + return "unauthorized" + default: + return "unknown OCSP status: " + strconv.Itoa(int(r)) + } +} + +// ResponseError is an error that may be returned by ParseResponse to indicate +// that the response itself is an error, not just that its indicating that a +// certificate is revoked, unknown, etc. +type ResponseError struct { + Status ResponseStatus +} + +func (r ResponseError) Error() string { + return "ocsp: error from server: " + r.Status.String() +} + +// These are internal structures that reflect the ASN.1 structure of an OCSP +// response. See RFC 2560, section 4.2. + +type certID struct { + HashAlgorithm pkix.AlgorithmIdentifier + NameHash []byte + IssuerKeyHash []byte + SerialNumber *big.Int +} + +// https://tools.ietf.org/html/rfc2560#section-4.1.1 +type ocspRequest struct { + TBSRequest tbsRequest +} + +type tbsRequest struct { + Version int `asn1:"explicit,tag:0,default:0,optional"` + RequestorName pkix.RDNSequence `asn1:"explicit,tag:1,optional"` + RequestList []request +} + +type request struct { + Cert certID +} + +type responseASN1 struct { + Status asn1.Enumerated + Response responseBytes `asn1:"explicit,tag:0,optional"` +} + +type responseBytes struct { + ResponseType asn1.ObjectIdentifier + Response []byte +} + +type basicResponse struct { + TBSResponseData responseData + SignatureAlgorithm pkix.AlgorithmIdentifier + Signature asn1.BitString + Certificates []asn1.RawValue `asn1:"explicit,tag:0,optional"` +} + +type responseData struct { + Raw asn1.RawContent + Version int `asn1:"optional,default:0,explicit,tag:0"` + RawResponderID asn1.RawValue + ProducedAt time.Time `asn1:"generalized"` + Responses []singleResponse +} + +type singleResponse struct { + CertID certID + Good asn1.Flag `asn1:"tag:0,optional"` + Revoked revokedInfo `asn1:"tag:1,optional"` + Unknown asn1.Flag `asn1:"tag:2,optional"` + ThisUpdate time.Time `asn1:"generalized"` + NextUpdate time.Time `asn1:"generalized,explicit,tag:0,optional"` + SingleExtensions []pkix.Extension `asn1:"explicit,tag:1,optional"` +} + +type revokedInfo struct { + RevocationTime time.Time `asn1:"generalized"` + Reason asn1.Enumerated `asn1:"explicit,tag:0,optional"` +} + +var ( + oidSignatureMD2WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 2} + oidSignatureMD5WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 4} + oidSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5} + oidSignatureSHA256WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11} + oidSignatureSHA384WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12} + oidSignatureSHA512WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13} + oidSignatureDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3} + oidSignatureDSAWithSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 2} + oidSignatureECDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1} + oidSignatureECDSAWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2} + oidSignatureECDSAWithSHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3} + oidSignatureECDSAWithSHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4} +) + +var hashOIDs = map[crypto.Hash]asn1.ObjectIdentifier{ + crypto.SHA1: asn1.ObjectIdentifier([]int{1, 3, 14, 3, 2, 26}), + crypto.SHA256: asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 1}), + crypto.SHA384: asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 2}), + crypto.SHA512: asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 2, 3}), +} + +// TODO(rlb): This is also from crypto/x509, so same comment as AGL's below +var signatureAlgorithmDetails = []struct { + algo x509.SignatureAlgorithm + oid asn1.ObjectIdentifier + pubKeyAlgo x509.PublicKeyAlgorithm + hash crypto.Hash +}{ + {x509.MD2WithRSA, oidSignatureMD2WithRSA, x509.RSA, crypto.Hash(0) /* no value for MD2 */}, + {x509.MD5WithRSA, oidSignatureMD5WithRSA, x509.RSA, crypto.MD5}, + {x509.SHA1WithRSA, oidSignatureSHA1WithRSA, x509.RSA, crypto.SHA1}, + {x509.SHA256WithRSA, oidSignatureSHA256WithRSA, x509.RSA, crypto.SHA256}, + {x509.SHA384WithRSA, oidSignatureSHA384WithRSA, x509.RSA, crypto.SHA384}, + {x509.SHA512WithRSA, oidSignatureSHA512WithRSA, x509.RSA, crypto.SHA512}, + {x509.DSAWithSHA1, oidSignatureDSAWithSHA1, x509.DSA, crypto.SHA1}, + {x509.DSAWithSHA256, oidSignatureDSAWithSHA256, x509.DSA, crypto.SHA256}, + {x509.ECDSAWithSHA1, oidSignatureECDSAWithSHA1, x509.ECDSA, crypto.SHA1}, + {x509.ECDSAWithSHA256, oidSignatureECDSAWithSHA256, x509.ECDSA, crypto.SHA256}, + {x509.ECDSAWithSHA384, oidSignatureECDSAWithSHA384, x509.ECDSA, crypto.SHA384}, + {x509.ECDSAWithSHA512, oidSignatureECDSAWithSHA512, x509.ECDSA, crypto.SHA512}, +} + +// TODO(rlb): This is also from crypto/x509, so same comment as AGL's below +func signingParamsForPublicKey(pub interface{}, requestedSigAlgo x509.SignatureAlgorithm) (hashFunc crypto.Hash, sigAlgo pkix.AlgorithmIdentifier, err error) { + var pubType x509.PublicKeyAlgorithm + + switch pub := pub.(type) { + case *rsa.PublicKey: + pubType = x509.RSA + hashFunc = crypto.SHA256 + sigAlgo.Algorithm = oidSignatureSHA256WithRSA + sigAlgo.Parameters = asn1.RawValue{ + Tag: 5, + } + + case *ecdsa.PublicKey: + pubType = x509.ECDSA + + switch pub.Curve { + case elliptic.P224(), elliptic.P256(): + hashFunc = crypto.SHA256 + sigAlgo.Algorithm = oidSignatureECDSAWithSHA256 + case elliptic.P384(): + hashFunc = crypto.SHA384 + sigAlgo.Algorithm = oidSignatureECDSAWithSHA384 + case elliptic.P521(): + hashFunc = crypto.SHA512 + sigAlgo.Algorithm = oidSignatureECDSAWithSHA512 + default: + err = errors.New("x509: unknown elliptic curve") + } + + default: + err = errors.New("x509: only RSA and ECDSA keys supported") + } + + if err != nil { + return + } + + if requestedSigAlgo == 0 { + return + } + + found := false + for _, details := range signatureAlgorithmDetails { + if details.algo == requestedSigAlgo { + if details.pubKeyAlgo != pubType { + err = errors.New("x509: requested SignatureAlgorithm does not match private key type") + return + } + sigAlgo.Algorithm, hashFunc = details.oid, details.hash + if hashFunc == 0 { + err = errors.New("x509: cannot sign with hash function requested") + return + } + found = true + break + } + } + + if !found { + err = errors.New("x509: unknown SignatureAlgorithm") + } + + return +} + +// TODO(agl): this is taken from crypto/x509 and so should probably be exported +// from crypto/x509 or crypto/x509/pkix. +func getSignatureAlgorithmFromOID(oid asn1.ObjectIdentifier) x509.SignatureAlgorithm { + for _, details := range signatureAlgorithmDetails { + if oid.Equal(details.oid) { + return details.algo + } + } + return x509.UnknownSignatureAlgorithm +} + +// TODO(rlb): This is not taken from crypto/x509, but it's of the same general form. +func getHashAlgorithmFromOID(target asn1.ObjectIdentifier) crypto.Hash { + for hash, oid := range hashOIDs { + if oid.Equal(target) { + return hash + } + } + return crypto.Hash(0) +} + +func getOIDFromHashAlgorithm(target crypto.Hash) asn1.ObjectIdentifier { + for hash, oid := range hashOIDs { + if hash == target { + return oid + } + } + return nil +} + +// This is the exposed reflection of the internal OCSP structures. + +// The status values that can be expressed in OCSP. See RFC 6960. +const ( + // Good means that the certificate is valid. + Good = iota + // Revoked means that the certificate has been deliberately revoked. + Revoked + // Unknown means that the OCSP responder doesn't know about the certificate. + Unknown + // ServerFailed is unused and was never used (see + // https://go-review.googlesource.com/#/c/18944). ParseResponse will + // return a ResponseError when an error response is parsed. + ServerFailed +) + +// The enumerated reasons for revoking a certificate. See RFC 5280. +const ( + Unspecified = iota + KeyCompromise = iota + CACompromise = iota + AffiliationChanged = iota + Superseded = iota + CessationOfOperation = iota + CertificateHold = iota + _ = iota + RemoveFromCRL = iota + PrivilegeWithdrawn = iota + AACompromise = iota +) + +// Request represents an OCSP request. See RFC 6960. +type Request struct { + HashAlgorithm crypto.Hash + IssuerNameHash []byte + IssuerKeyHash []byte + SerialNumber *big.Int +} + +// Marshal marshals the OCSP request to ASN.1 DER encoded form. +func (req *Request) Marshal() ([]byte, error) { + hashAlg := getOIDFromHashAlgorithm(req.HashAlgorithm) + if hashAlg == nil { + return nil, errors.New("Unknown hash algorithm") + } + return asn1.Marshal(ocspRequest{ + tbsRequest{ + Version: 0, + RequestList: []request{ + { + Cert: certID{ + pkix.AlgorithmIdentifier{ + Algorithm: hashAlg, + Parameters: asn1.RawValue{Tag: 5 /* ASN.1 NULL */}, + }, + req.IssuerNameHash, + req.IssuerKeyHash, + req.SerialNumber, + }, + }, + }, + }, + }) +} + +// Response represents an OCSP response containing a single SingleResponse. See +// RFC 6960. +type Response struct { + // Status is one of {Good, Revoked, Unknown} + Status int + SerialNumber *big.Int + ProducedAt, ThisUpdate, NextUpdate, RevokedAt time.Time + RevocationReason int + Certificate *x509.Certificate + // TBSResponseData contains the raw bytes of the signed response. If + // Certificate is nil then this can be used to verify Signature. + TBSResponseData []byte + Signature []byte + SignatureAlgorithm x509.SignatureAlgorithm + + // IssuerHash is the hash used to compute the IssuerNameHash and IssuerKeyHash. + // Valid values are crypto.SHA1, crypto.SHA256, crypto.SHA384, and crypto.SHA512. + // If zero, the default is crypto.SHA1. + IssuerHash crypto.Hash + + // RawResponderName optionally contains the DER-encoded subject of the + // responder certificate. Exactly one of RawResponderName and + // ResponderKeyHash is set. + RawResponderName []byte + // ResponderKeyHash optionally contains the SHA-1 hash of the + // responder's public key. Exactly one of RawResponderName and + // ResponderKeyHash is set. + ResponderKeyHash []byte + + // Extensions contains raw X.509 extensions from the singleExtensions field + // of the OCSP response. When parsing certificates, this can be used to + // extract non-critical extensions that are not parsed by this package. When + // marshaling OCSP responses, the Extensions field is ignored, see + // ExtraExtensions. + Extensions []pkix.Extension + + // ExtraExtensions contains extensions to be copied, raw, into any marshaled + // OCSP response (in the singleExtensions field). Values override any + // extensions that would otherwise be produced based on the other fields. The + // ExtraExtensions field is not populated when parsing certificates, see + // Extensions. + ExtraExtensions []pkix.Extension +} + +// These are pre-serialized error responses for the various non-success codes +// defined by OCSP. The Unauthorized code in particular can be used by an OCSP +// responder that supports only pre-signed responses as a response to requests +// for certificates with unknown status. See RFC 5019. +var ( + MalformedRequestErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x01} + InternalErrorErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x02} + TryLaterErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x03} + SigRequredErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x05} + UnauthorizedErrorResponse = []byte{0x30, 0x03, 0x0A, 0x01, 0x06} +) + +// CheckSignatureFrom checks that the signature in resp is a valid signature +// from issuer. This should only be used if resp.Certificate is nil. Otherwise, +// the OCSP response contained an intermediate certificate that created the +// signature. That signature is checked by ParseResponse and only +// resp.Certificate remains to be validated. +func (resp *Response) CheckSignatureFrom(issuer *x509.Certificate) error { + return issuer.CheckSignature(resp.SignatureAlgorithm, resp.TBSResponseData, resp.Signature) +} + +// ParseError results from an invalid OCSP response. +type ParseError string + +func (p ParseError) Error() string { + return string(p) +} + +// ParseRequest parses an OCSP request in DER form. It only supports +// requests for a single certificate. Signed requests are not supported. +// If a request includes a signature, it will result in a ParseError. +func ParseRequest(bytes []byte) (*Request, error) { + var req ocspRequest + rest, err := asn1.Unmarshal(bytes, &req) + if err != nil { + return nil, err + } + if len(rest) > 0 { + return nil, ParseError("trailing data in OCSP request") + } + + if len(req.TBSRequest.RequestList) == 0 { + return nil, ParseError("OCSP request contains no request body") + } + innerRequest := req.TBSRequest.RequestList[0] + + hashFunc := getHashAlgorithmFromOID(innerRequest.Cert.HashAlgorithm.Algorithm) + if hashFunc == crypto.Hash(0) { + return nil, ParseError("OCSP request uses unknown hash function") + } + + return &Request{ + HashAlgorithm: hashFunc, + IssuerNameHash: innerRequest.Cert.NameHash, + IssuerKeyHash: innerRequest.Cert.IssuerKeyHash, + SerialNumber: innerRequest.Cert.SerialNumber, + }, nil +} + +// ParseResponse parses an OCSP response in DER form. It only supports +// responses for a single certificate. If the response contains a certificate +// then the signature over the response is checked. If issuer is not nil then +// it will be used to validate the signature or embedded certificate. +// +// Invalid responses and parse failures will result in a ParseError. +// Error responses will result in a ResponseError. +func ParseResponse(bytes []byte, issuer *x509.Certificate) (*Response, error) { + return ParseResponseForCert(bytes, nil, issuer) +} + +// ParseResponseForCert parses an OCSP response in DER form and searches for a +// Response relating to cert. If such a Response is found and the OCSP response +// contains a certificate then the signature over the response is checked. If +// issuer is not nil then it will be used to validate the signature or embedded +// certificate. +// +// Invalid responses and parse failures will result in a ParseError. +// Error responses will result in a ResponseError. +func ParseResponseForCert(bytes []byte, cert, issuer *x509.Certificate) (*Response, error) { + var resp responseASN1 + rest, err := asn1.Unmarshal(bytes, &resp) + if err != nil { + return nil, err + } + if len(rest) > 0 { + return nil, ParseError("trailing data in OCSP response") + } + + if status := ResponseStatus(resp.Status); status != Success { + return nil, ResponseError{status} + } + + if !resp.Response.ResponseType.Equal(idPKIXOCSPBasic) { + return nil, ParseError("bad OCSP response type") + } + + var basicResp basicResponse + rest, err = asn1.Unmarshal(resp.Response.Response, &basicResp) + if err != nil { + return nil, err + } + + 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") + } + + var singleResp singleResponse + if cert == nil { + singleResp = basicResp.TBSResponseData.Responses[0] + } else { + match := false + for _, resp := range basicResp.TBSResponseData.Responses { + if cert == nil || cert.SerialNumber.Cmp(resp.CertID.SerialNumber) == 0 { + singleResp = resp + match = true + break + } + } + if !match { + return nil, ParseError("no response matching the supplied certificate") + } + } + + ret := &Response{ + TBSResponseData: basicResp.TBSResponseData.Raw, + Signature: basicResp.Signature.RightAlign(), + SignatureAlgorithm: getSignatureAlgorithmFromOID(basicResp.SignatureAlgorithm.Algorithm), + Extensions: singleResp.SingleExtensions, + SerialNumber: singleResp.CertID.SerialNumber, + ProducedAt: basicResp.TBSResponseData.ProducedAt, + ThisUpdate: singleResp.ThisUpdate, + NextUpdate: singleResp.NextUpdate, + } + + // 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()) + } + } + + for _, ext := range singleResp.SingleExtensions { + if ext.Critical { + return nil, ParseError("unsupported critical extension") + } + } + + for h, oid := range hashOIDs { + if singleResp.CertID.HashAlgorithm.Algorithm.Equal(oid) { + ret.IssuerHash = h + break + } + } + if ret.IssuerHash == 0 { + return nil, ParseError("unsupported issuer hash algorithm") + } + + switch { + case bool(singleResp.Good): + ret.Status = Good + case bool(singleResp.Unknown): + ret.Status = Unknown + default: + ret.Status = Revoked + ret.RevokedAt = singleResp.Revoked.RevocationTime + ret.RevocationReason = int(singleResp.Revoked.Reason) + } + + 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, + }, + }) +} |