pkix.go

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package pkix contains shared, low level structures used for ASN.1 parsing
     6  // and serialization of X.509 certificates, CRL and OCSP.
     7  package pkix
     8  
     9  import (
    10  	"encoding/asn1"
    11  	"encoding/hex"
    12  	"fmt"
    13  	"math/big"
    14  	"time"
    15  )
    16  
    17  // AlgorithmIdentifier represents the ASN.1 structure of the same name. See RFC
    18  // 5280, section 4.1.1.2.
    19  type AlgorithmIdentifier struct {
    20  	Algorithm  asn1.ObjectIdentifier
    21  	Parameters asn1.RawValue `asn1:"optional"`
    22  }
    23  
    24  type RDNSequence []RelativeDistinguishedNameSET
    25  
    26  var attributeTypeNames = map[string]string{
    27  	"2.5.4.6":  "C",
    28  	"2.5.4.10": "O",
    29  	"2.5.4.11": "OU",
    30  	"2.5.4.3":  "CN",
    31  	"2.5.4.5":  "SERIALNUMBER",
    32  	"2.5.4.7":  "L",
    33  	"2.5.4.8":  "ST",
    34  	"2.5.4.9":  "STREET",
    35  	"2.5.4.17": "POSTALCODE",
    36  }
    37  
    38  // String returns a string representation of the sequence r,
    39  // roughly following the RFC 2253 Distinguished Names syntax.
    40  func (r RDNSequence) String() string {
    41  	s := ""
    42  	for i := 0; i < len(r); i++ {
    43  		rdn := r[len(r)-1-i]
    44  		if i > 0 {
    45  			s += ","
    46  		}
    47  		for j, tv := range rdn {
    48  			if j > 0 {
    49  				s += "+"
    50  			}
    51  
    52  			oidString := tv.Type.String()
    53  			typeName, ok := attributeTypeNames[oidString]
    54  			if !ok {
    55  				derBytes, err := asn1.Marshal(tv.Value)
    56  				if err == nil {
    57  					s += oidString + "=#" + hex.EncodeToString(derBytes)
    58  					continue // No value escaping necessary.
    59  				}
    60  
    61  				typeName = oidString
    62  			}
    63  
    64  			valueString := fmt.Sprint(tv.Value)
    65  			escaped := make([]rune, 0, len(valueString))
    66  
    67  			for k, c := range valueString {
    68  				escape := false
    69  
    70  				switch c {
    71  				case ',', '+', '"', '\\', '<', '>', ';':
    72  					escape = true
    73  
    74  				case ' ':
    75  					escape = k == 0 || k == len(valueString)-1
    76  
    77  				case '#':
    78  					escape = k == 0
    79  				}
    80  
    81  				if escape {
    82  					escaped = append(escaped, '\\', c)
    83  				} else {
    84  					escaped = append(escaped, c)
    85  				}
    86  			}
    87  
    88  			s += typeName + "=" + string(escaped)
    89  		}
    90  	}
    91  
    92  	return s
    93  }
    94  
    95  type RelativeDistinguishedNameSET []AttributeTypeAndValue
    96  
    97  // AttributeTypeAndValue mirrors the ASN.1 structure of the same name in
    98  // RFC 5280, Section 4.1.2.4.
    99  type AttributeTypeAndValue struct {
   100  	Type  asn1.ObjectIdentifier
   101  	Value any
   102  }
   103  
   104  // AttributeTypeAndValueSET represents a set of ASN.1 sequences of
   105  // [AttributeTypeAndValue] sequences from RFC 2986 (PKCS #10).
   106  type AttributeTypeAndValueSET struct {
   107  	Type  asn1.ObjectIdentifier
   108  	Value [][]AttributeTypeAndValue `asn1:"set"`
   109  }
   110  
   111  // Extension represents the ASN.1 structure of the same name. See RFC
   112  // 5280, section 4.2.
   113  type Extension struct {
   114  	Id       asn1.ObjectIdentifier
   115  	Critical bool `asn1:"optional"`
   116  	Value    []byte
   117  }
   118  
   119  // Name represents an X.509 distinguished name. This only includes the common
   120  // elements of a DN. Note that Name is only an approximation of the X.509
   121  // structure. If an accurate representation is needed, asn1.Unmarshal the raw
   122  // subject or issuer as an [RDNSequence].
   123  type Name struct {
   124  	Country, Organization, OrganizationalUnit []string
   125  	Locality, Province                        []string
   126  	StreetAddress, PostalCode                 []string
   127  	SerialNumber, CommonName                  string
   128  
   129  	// Names contains all parsed attributes. When parsing distinguished names,
   130  	// this can be used to extract non-standard attributes that are not parsed
   131  	// by this package. When marshaling to RDNSequences, the Names field is
   132  	// ignored, see ExtraNames.
   133  	Names []AttributeTypeAndValue
   134  
   135  	// ExtraNames contains attributes to be copied, raw, into any marshaled
   136  	// distinguished names. Values override any attributes with the same OID.
   137  	// The ExtraNames field is not populated when parsing, see Names.
   138  	ExtraNames []AttributeTypeAndValue
   139  }
   140  
   141  // FillFromRDNSequence populates n from the provided [RDNSequence].
   142  // Multi-entry RDNs are flattened, all entries are added to the
   143  // relevant n fields, and the grouping is not preserved.
   144  func (n *Name) FillFromRDNSequence(rdns *RDNSequence) {
   145  	for _, rdn := range *rdns {
   146  		if len(rdn) == 0 {
   147  			continue
   148  		}
   149  
   150  		for _, atv := range rdn {
   151  			n.Names = append(n.Names, atv)
   152  			value, ok := atv.Value.(string)
   153  			if !ok {
   154  				continue
   155  			}
   156  
   157  			t := atv.Type
   158  			if len(t) == 4 && t[0] == 2 && t[1] == 5 && t[2] == 4 {
   159  				switch t[3] {
   160  				case 3:
   161  					n.CommonName = value
   162  				case 5:
   163  					n.SerialNumber = value
   164  				case 6:
   165  					n.Country = append(n.Country, value)
   166  				case 7:
   167  					n.Locality = append(n.Locality, value)
   168  				case 8:
   169  					n.Province = append(n.Province, value)
   170  				case 9:
   171  					n.StreetAddress = append(n.StreetAddress, value)
   172  				case 10:
   173  					n.Organization = append(n.Organization, value)
   174  				case 11:
   175  					n.OrganizationalUnit = append(n.OrganizationalUnit, value)
   176  				case 17:
   177  					n.PostalCode = append(n.PostalCode, value)
   178  				}
   179  			}
   180  		}
   181  	}
   182  }
   183  
   184  var (
   185  	oidCountry            = []int{2, 5, 4, 6}
   186  	oidOrganization       = []int{2, 5, 4, 10}
   187  	oidOrganizationalUnit = []int{2, 5, 4, 11}
   188  	oidCommonName         = []int{2, 5, 4, 3}
   189  	oidSerialNumber       = []int{2, 5, 4, 5}
   190  	oidLocality           = []int{2, 5, 4, 7}
   191  	oidProvince           = []int{2, 5, 4, 8}
   192  	oidStreetAddress      = []int{2, 5, 4, 9}
   193  	oidPostalCode         = []int{2, 5, 4, 17}
   194  )
   195  
   196  // appendRDNs appends a relativeDistinguishedNameSET to the given RDNSequence
   197  // and returns the new value. The relativeDistinguishedNameSET contains an
   198  // attributeTypeAndValue for each of the given values. See RFC 5280, A.1, and
   199  // search for AttributeTypeAndValue.
   200  func (n Name) appendRDNs(in RDNSequence, values []string, oid asn1.ObjectIdentifier) RDNSequence {
   201  	if len(values) == 0 || oidInAttributeTypeAndValue(oid, n.ExtraNames) {
   202  		return in
   203  	}
   204  
   205  	s := make([]AttributeTypeAndValue, len(values))
   206  	for i, value := range values {
   207  		s[i].Type = oid
   208  		s[i].Value = value
   209  	}
   210  
   211  	return append(in, s)
   212  }
   213  
   214  // ToRDNSequence converts n into a single [RDNSequence]. The following
   215  // attributes are encoded as multi-value RDNs:
   216  //
   217  //   - Country
   218  //   - Organization
   219  //   - OrganizationalUnit
   220  //   - Locality
   221  //   - Province
   222  //   - StreetAddress
   223  //   - PostalCode
   224  //
   225  // Each ExtraNames entry is encoded as an individual RDN.
   226  func (n Name) ToRDNSequence() (ret RDNSequence) {
   227  	ret = n.appendRDNs(ret, n.Country, oidCountry)
   228  	ret = n.appendRDNs(ret, n.Province, oidProvince)
   229  	ret = n.appendRDNs(ret, n.Locality, oidLocality)
   230  	ret = n.appendRDNs(ret, n.StreetAddress, oidStreetAddress)
   231  	ret = n.appendRDNs(ret, n.PostalCode, oidPostalCode)
   232  	ret = n.appendRDNs(ret, n.Organization, oidOrganization)
   233  	ret = n.appendRDNs(ret, n.OrganizationalUnit, oidOrganizationalUnit)
   234  	if len(n.CommonName) > 0 {
   235  		ret = n.appendRDNs(ret, []string{n.CommonName}, oidCommonName)
   236  	}
   237  	if len(n.SerialNumber) > 0 {
   238  		ret = n.appendRDNs(ret, []string{n.SerialNumber}, oidSerialNumber)
   239  	}
   240  	for _, atv := range n.ExtraNames {
   241  		ret = append(ret, []AttributeTypeAndValue{atv})
   242  	}
   243  
   244  	return ret
   245  }
   246  
   247  // String returns the string form of n, roughly following
   248  // the RFC 2253 Distinguished Names syntax.
   249  func (n Name) String() string {
   250  	var rdns RDNSequence
   251  	// If there are no ExtraNames, surface the parsed value (all entries in
   252  	// Names) instead.
   253  	if n.ExtraNames == nil {
   254  		for _, atv := range n.Names {
   255  			t := atv.Type
   256  			if len(t) == 4 && t[0] == 2 && t[1] == 5 && t[2] == 4 {
   257  				switch t[3] {
   258  				case 3, 5, 6, 7, 8, 9, 10, 11, 17:
   259  					// These attributes were already parsed into named fields.
   260  					continue
   261  				}
   262  			}
   263  			// Place non-standard parsed values at the beginning of the sequence
   264  			// so they will be at the end of the string. See Issue 39924.
   265  			rdns = append(rdns, []AttributeTypeAndValue{atv})
   266  		}
   267  	}
   268  	rdns = append(rdns, n.ToRDNSequence()...)
   269  	return rdns.String()
   270  }
   271  
   272  // oidInAttributeTypeAndValue reports whether a type with the given OID exists
   273  // in atv.
   274  func oidInAttributeTypeAndValue(oid asn1.ObjectIdentifier, atv []AttributeTypeAndValue) bool {
   275  	for _, a := range atv {
   276  		if a.Type.Equal(oid) {
   277  			return true
   278  		}
   279  	}
   280  	return false
   281  }
   282  
   283  // CertificateList represents the ASN.1 structure of the same name. See RFC
   284  // 5280, section 5.1. Use Certificate.CheckCRLSignature to verify the
   285  // signature.
   286  //
   287  // Deprecated: x509.RevocationList should be used instead.
   288  type CertificateList struct {
   289  	TBSCertList        TBSCertificateList
   290  	SignatureAlgorithm AlgorithmIdentifier
   291  	SignatureValue     asn1.BitString
   292  }
   293  
   294  // HasExpired reports whether certList should have been updated by now.
   295  func (certList *CertificateList) HasExpired(now time.Time) bool {
   296  	return !now.Before(certList.TBSCertList.NextUpdate)
   297  }
   298  
   299  // TBSCertificateList represents the ASN.1 structure of the same name. See RFC
   300  // 5280, section 5.1.
   301  //
   302  // Deprecated: x509.RevocationList should be used instead.
   303  type TBSCertificateList struct {
   304  	Raw                 asn1.RawContent
   305  	Version             int `asn1:"optional,default:0"`
   306  	Signature           AlgorithmIdentifier
   307  	Issuer              RDNSequence
   308  	ThisUpdate          time.Time
   309  	NextUpdate          time.Time            `asn1:"optional"`
   310  	RevokedCertificates []RevokedCertificate `asn1:"optional"`
   311  	Extensions          []Extension          `asn1:"tag:0,optional,explicit"`
   312  }
   313  
   314  // RevokedCertificate represents the ASN.1 structure of the same name. See RFC
   315  // 5280, section 5.1.
   316  type RevokedCertificate struct {
   317  	SerialNumber   *big.Int
   318  	RevocationTime time.Time
   319  	Extensions     []Extension `asn1:"optional"`
   320  }
   321
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