Source: pkix.go in package crypto/x509/pkix

Package pkix contains shared, low level structures used for ASN.1 parsing and serialization of X.509 certificates, CRL and OCSP.

package pkix

import (
	"encoding/asn1"
	"encoding/hex"
	"fmt"
	"math/big"
	"time"
)

AlgorithmIdentifier represents the ASN.1 structure of the same name. See RFC 5280, section 4.1.1.2.

type AlgorithmIdentifier struct {
	Algorithm  asn1.ObjectIdentifier
	Parameters asn1.RawValue `asn1:"optional"`
}

type RDNSequence []RelativeDistinguishedNameSET

var attributeTypeNames = map[string]string{
	"2.5.4.6":  "C",
	"2.5.4.10": "O",
	"2.5.4.11": "OU",
	"2.5.4.3":  "CN",
	"2.5.4.5":  "SERIALNUMBER",
	"2.5.4.7":  "L",
	"2.5.4.8":  "ST",
	"2.5.4.9":  "STREET",
	"2.5.4.17": "POSTALCODE",
}

String returns a string representation of the sequence r, roughly following the RFC 2253 Distinguished Names syntax.

func (r RDNSequence) String() string {
	s := ""
	for i := 0; i < len(r); i++ {
		rdn := r[len(r)-1-i]
		if i > 0 {
			s += ","
		}
		for j, tv := range rdn {
			if j > 0 {
				s += "+"
			}

			oidString := tv.Type.String()
			typeName, ok := attributeTypeNames[oidString]
			if !ok {
				derBytes, err := asn1.Marshal(tv.Value)
				if err == nil {
					s += oidString + "=#" + hex.EncodeToString(derBytes)
					continue // No value escaping necessary.
				}

				typeName = oidString
			}

			valueString := fmt.Sprint(tv.Value)
			escaped := make([]rune, 0, len(valueString))

			for k, c := range valueString {
				escape := false

				switch c {
				case ',', '+', '"', '\\', '<', '>', ';':
					escape = true

				case ' ':
					escape = k == 0 || k == len(valueString)-1

				case '#':
					escape = k == 0
				}

				if escape {
					escaped = append(escaped, '\\', c)
				} else {
					escaped = append(escaped, c)
				}
			}

			s += typeName + "=" + string(escaped)
		}
	}

	return s
}

type RelativeDistinguishedNameSET []AttributeTypeAndValue

AttributeTypeAndValue mirrors the ASN.1 structure of the same name in RFC 5280, Section 4.1.2.4.

type AttributeTypeAndValue struct {
	Type  asn1.ObjectIdentifier
	Value interface{}
}

AttributeTypeAndValueSET represents a set of ASN.1 sequences of AttributeTypeAndValue sequences from RFC 2986 (PKCS #10).

type AttributeTypeAndValueSET struct {
	Type  asn1.ObjectIdentifier
	Value [][]AttributeTypeAndValue `asn1:"set"`
}

Extension represents the ASN.1 structure of the same name. See RFC 5280, section 4.2.

type Extension struct {
	Id       asn1.ObjectIdentifier
	Critical bool `asn1:"optional"`
	Value    []byte
}

Name represents an X.509 distinguished name. This only includes the common elements of a DN. Note that Name is only an approximation of the X.509 structure. If an accurate representation is needed, asn1.Unmarshal the raw subject or issuer as an RDNSequence.

type Name struct {
	Country, Organization, OrganizationalUnit []string
	Locality, Province                        []string
	StreetAddress, PostalCode                 []string
	SerialNumber, CommonName                  string

Names contains all parsed attributes. When parsing distinguished names, this can be used to extract non-standard attributes that are not parsed by this package. When marshaling to RDNSequences, the Names field is ignored, see ExtraNames.

	Names []AttributeTypeAndValue

ExtraNames contains attributes to be copied, raw, into any marshaled distinguished names. Values override any attributes with the same OID. The ExtraNames field is not populated when parsing, see Names.

	ExtraNames []AttributeTypeAndValue
}

FillFromRDNSequence populates n from the provided RDNSequence. Multi-entry RDNs are flattened, all entries are added to the relevant n fields, and the grouping is not preserved.

func (n *Name) FillFromRDNSequence(rdns *RDNSequence) {
	for _, rdn := range *rdns {
		if len(rdn) == 0 {
			continue
		}

		for _, atv := range rdn {
			n.Names = append(n.Names, atv)
			value, ok := atv.Value.(string)
			if !ok {
				continue
			}

			t := atv.Type
			if len(t) == 4 && t[0] == 2 && t[1] == 5 && t[2] == 4 {
				switch t[3] {
				case 3:
					n.CommonName = value
				case 5:
					n.SerialNumber = value
				case 6:
					n.Country = append(n.Country, value)
				case 7:
					n.Locality = append(n.Locality, value)
				case 8:
					n.Province = append(n.Province, value)
				case 9:
					n.StreetAddress = append(n.StreetAddress, value)
				case 10:
					n.Organization = append(n.Organization, value)
				case 11:
					n.OrganizationalUnit = append(n.OrganizationalUnit, value)
				case 17:
					n.PostalCode = append(n.PostalCode, value)
				}
			}
		}
	}
}

var (
	oidCountry            = []int{2, 5, 4, 6}
	oidOrganization       = []int{2, 5, 4, 10}
	oidOrganizationalUnit = []int{2, 5, 4, 11}
	oidCommonName         = []int{2, 5, 4, 3}
	oidSerialNumber       = []int{2, 5, 4, 5}
	oidLocality           = []int{2, 5, 4, 7}
	oidProvince           = []int{2, 5, 4, 8}
	oidStreetAddress      = []int{2, 5, 4, 9}
	oidPostalCode         = []int{2, 5, 4, 17}
)

appendRDNs appends a relativeDistinguishedNameSET to the given RDNSequence and returns the new value. The relativeDistinguishedNameSET contains an attributeTypeAndValue for each of the given values. See RFC 5280, A.1, and search for AttributeTypeAndValue.

func (n Name) appendRDNs(in RDNSequence, values []string, oid asn1.ObjectIdentifier) RDNSequence {
	if len(values) == 0 || oidInAttributeTypeAndValue(oid, n.ExtraNames) {
		return in
	}

	s := make([]AttributeTypeAndValue, len(values))
	for i, value := range values {
		s[i].Type = oid
		s[i].Value = value
	}

	return append(in, s)
}

ToRDNSequence converts n into a single RDNSequence. The following attributes are encoded as multi-value RDNs: - Country - Organization - OrganizationalUnit - Locality - Province - StreetAddress - PostalCode Each ExtraNames entry is encoded as an individual RDN.

func (n Name) ToRDNSequence() (ret RDNSequence) {
	ret = n.appendRDNs(ret, n.Country, oidCountry)
	ret = n.appendRDNs(ret, n.Province, oidProvince)
	ret = n.appendRDNs(ret, n.Locality, oidLocality)
	ret = n.appendRDNs(ret, n.StreetAddress, oidStreetAddress)
	ret = n.appendRDNs(ret, n.PostalCode, oidPostalCode)
	ret = n.appendRDNs(ret, n.Organization, oidOrganization)
	ret = n.appendRDNs(ret, n.OrganizationalUnit, oidOrganizationalUnit)
	if len(n.CommonName) > 0 {
		ret = n.appendRDNs(ret, []string{n.CommonName}, oidCommonName)
	}
	if len(n.SerialNumber) > 0 {
		ret = n.appendRDNs(ret, []string{n.SerialNumber}, oidSerialNumber)
	}
	for _, atv := range n.ExtraNames {
		ret = append(ret, []AttributeTypeAndValue{atv})
	}

	return ret
}

String returns the string form of n, roughly following the RFC 2253 Distinguished Names syntax.

func (n Name) String() string {

If there are no ExtraNames, surface the parsed value (all entries in Names) instead.

	if n.ExtraNames == nil {
		for _, atv := range n.Names {
			t := atv.Type
			if len(t) == 4 && t[0] == 2 && t[1] == 5 && t[2] == 4 {
				switch t[3] {

These attributes were already parsed into named fields.

					continue
				}

Place non-standard parsed values at the beginning of the sequence so they will be at the end of the string. See Issue 39924.

			rdns = append(rdns, []AttributeTypeAndValue{atv})
		}
	}
	rdns = append(rdns, n.ToRDNSequence()...)
	return rdns.String()
}

oidInAttributeTypeAndValue reports whether a type with the given OID exists in atv.

func oidInAttributeTypeAndValue(oid asn1.ObjectIdentifier, atv []AttributeTypeAndValue) bool {
	for _, a := range atv {
		if a.Type.Equal(oid) {
			return true
		}
	}
	return false
}

CertificateList represents the ASN.1 structure of the same name. See RFC 5280, section 5.1. Use Certificate.CheckCRLSignature to verify the signature.

type CertificateList struct {
	TBSCertList        TBSCertificateList
	SignatureAlgorithm AlgorithmIdentifier
	SignatureValue     asn1.BitString
}

HasExpired reports whether certList should have been updated by now.

func (certList *CertificateList) HasExpired(now time.Time) bool {
	return !now.Before(certList.TBSCertList.NextUpdate)
}

TBSCertificateList represents the ASN.1 structure of the same name. See RFC 5280, section 5.1.

type TBSCertificateList struct {
	Raw                 asn1.RawContent
	Version             int `asn1:"optional,default:0"`
	Signature           AlgorithmIdentifier
	Issuer              RDNSequence
	ThisUpdate          time.Time
	NextUpdate          time.Time            `asn1:"optional"`
	RevokedCertificates []RevokedCertificate `asn1:"optional"`
	Extensions          []Extension          `asn1:"tag:0,optional,explicit"`
}

RevokedCertificate represents the ASN.1 structure of the same name. See RFC 5280, section 5.1.

type RevokedCertificate struct {
	SerialNumber   *big.Int
	RevocationTime time.Time
	Extensions     []Extension `asn1:"optional"`