Provided by: openssl_1.0.2g-1ubuntu4.20_amd64 bug

NAME

       x509v3_config - X509 V3 certificate extension configuration format

DESCRIPTION

       Several of the OpenSSL utilities can add extensions to a certificate or certificate
       request based on the contents of a configuration file.

       Typically the application will contain an option to point to an extension section. Each
       line of the extension section takes the form:

        extension_name=[critical,] extension_options

       If critical is present then the extension will be critical.

       The format of extension_options depends on the value of extension_name.

       There are four main types of extension: string extensions, multi-valued extensions, raw
       and arbitrary extensions.

       String extensions simply have a string which contains either the value itself or how it is
       obtained.

       For example:

        nsComment="This is a Comment"

       Multi-valued extensions have a short form and a long form. The short form is a list of
       names and values:

        basicConstraints=critical,CA:true,pathlen:1

       The long form allows the values to be placed in a separate section:

        basicConstraints=critical,@bs_section

        [bs_section]

        CA=true
        pathlen=1

       Both forms are equivalent.

       The syntax of raw extensions is governed by the extension code: it can for example contain
       data in multiple sections. The correct syntax to use is defined by the extension code
       itself: check out the certificate policies extension for an example.

       If an extension type is unsupported then the arbitrary extension syntax must be used, see
       the ARBITRARY EXTENSIONS section for more details.

STANDARD EXTENSIONS

       The following sections describe each supported extension in detail.

   Basic Constraints.
       This is a multi valued extension which indicates whether a certificate is a CA
       certificate. The first (mandatory) name is CA followed by TRUE or FALSE. If CA is TRUE
       then an optional pathlen name followed by an non-negative value can be included.

       For example:

        basicConstraints=CA:TRUE

        basicConstraints=CA:FALSE

        basicConstraints=critical,CA:TRUE, pathlen:0

       A CA certificate must include the basicConstraints value with the CA field set to TRUE. An
       end user certificate must either set CA to FALSE or exclude the extension entirely. Some
       software may require the inclusion of basicConstraints with CA set to FALSE for end entity
       certificates.

       The pathlen parameter indicates the maximum number of CAs that can appear below this one
       in a chain. So if you have a CA with a pathlen of zero it can only be used to sign end
       user certificates and not further CAs.

   Key Usage.
       Key usage is a multi valued extension consisting of a list of names of the permitted key
       usages.

       The supporte names are: digitalSignature, nonRepudiation, keyEncipherment,
       dataEncipherment, keyAgreement, keyCertSign, cRLSign, encipherOnly and decipherOnly.

       Examples:

        keyUsage=digitalSignature, nonRepudiation

        keyUsage=critical, keyCertSign

   Extended Key Usage.
       This extensions consists of a list of usages indicating purposes for which the certificate
       public key can be used for,

       These can either be object short names of the dotted numerical form of OIDs.  While any
       OID can be used only certain values make sense. In particular the following PKIX, NS and
       MS values are meaningful:

        Value                  Meaning
        -----                  -------
        serverAuth             SSL/TLS Web Server Authentication.
        clientAuth             SSL/TLS Web Client Authentication.
        codeSigning            Code signing.
        emailProtection        E-mail Protection (S/MIME).
        timeStamping           Trusted Timestamping
        msCodeInd              Microsoft Individual Code Signing (authenticode)
        msCodeCom              Microsoft Commercial Code Signing (authenticode)
        msCTLSign              Microsoft Trust List Signing
        msSGC                  Microsoft Server Gated Crypto
        msEFS                  Microsoft Encrypted File System
        nsSGC                  Netscape Server Gated Crypto

       Examples:

        extendedKeyUsage=critical,codeSigning,1.2.3.4
        extendedKeyUsage=nsSGC,msSGC

   Subject Key Identifier.
       This is really a string extension and can take two possible values. Either the word hash
       which will automatically follow the guidelines in RFC3280 or a hex string giving the
       extension value to include. The use of the hex string is strongly discouraged.

       Example:

        subjectKeyIdentifier=hash

   Authority Key Identifier.
       The authority key identifier extension permits two options. keyid and issuer: both can
       take the optional value "always".

       If the keyid option is present an attempt is made to copy the subject key identifier from
       the parent certificate. If the value "always" is present then an error is returned if the
       option fails.

       The issuer option copies the issuer and serial number from the issuer certificate. This
       will only be done if the keyid option fails or is not included unless the "always" flag
       will always include the value.

       Example:

        authorityKeyIdentifier=keyid,issuer

   Subject Alternative Name.
       The subject alternative name extension allows various literal values to be included in the
       configuration file. These include email (an email address) URI a uniform resource
       indicator, DNS (a DNS domain name), RID (a registered ID: OBJECT IDENTIFIER), IP (an IP
       address), dirName (a distinguished name) and otherName.

       The email option include a special 'copy' value. This will automatically include and email
       addresses contained in the certificate subject name in the extension.

       The IP address used in the IP options can be in either IPv4 or IPv6 format.

       The value of dirName should point to a section containing the distinguished name to use as
       a set of name value pairs. Multi values AVAs can be formed by prefacing the name with a +
       character.

       otherName can include arbitrary data associated with an OID: the value should be the OID
       followed by a semicolon and the content in standard ASN1_generate_nconf(3) format.

       Examples:

        subjectAltName=email:copy,email:my@other.address,URI:http://my.url.here/
        subjectAltName=IP:192.168.7.1
        subjectAltName=IP:13::17
        subjectAltName=email:my@other.address,RID:1.2.3.4
        subjectAltName=otherName:1.2.3.4;UTF8:some other identifier

        subjectAltName=dirName:dir_sect

        [dir_sect]
        C=UK
        O=My Organization
        OU=My Unit
        CN=My Name

   Issuer Alternative Name.
       The issuer alternative name option supports all the literal options of subject alternative
       name. It does not support the email:copy option because that would not make sense. It does
       support an additional issuer:copy option that will copy all the subject alternative name
       values from the issuer certificate (if possible).

       Example:

        issuserAltName = issuer:copy

   Authority Info Access.
       The authority information access extension gives details about how to access certain
       information relating to the CA. Its syntax is accessOID;location where location has the
       same syntax as subject alternative name (except that email:copy is not supported).
       accessOID can be any valid OID but only certain values are meaningful, for example OCSP
       and caIssuers.

       Example:

        authorityInfoAccess = OCSP;URI:http://ocsp.my.host/
        authorityInfoAccess = caIssuers;URI:http://my.ca/ca.html

   CRL distribution points.
       This is a multi-valued extension whose options can be either in name:value pair using the
       same form as subject alternative name or a single value representing a section name
       containing all the distribution point fields.

       For a name:value pair a new DistributionPoint with the fullName field set to the given
       value both the cRLissuer and reasons fields are omitted in this case.

       In the single option case the section indicated contains values for each field. In this
       section:

       If the name is "fullname" the value field should contain the full name of the distribution
       point in the same format as subject alternative name.

       If the name is "relativename" then the value field should contain a section name whose
       contents represent a DN fragment to be placed in this field.

       The name "CRLIssuer" if present should contain a value for this field in subject
       alternative name format.

       If the name is "reasons" the value field should consist of a comma separated field
       containing the reasons. Valid reasons are: "keyCompromise", "CACompromise",
       "affiliationChanged", "superseded", "cessationOfOperation", "certificateHold",
       "privilegeWithdrawn" and "AACompromise".

       Simple examples:

        crlDistributionPoints=URI:http://myhost.com/myca.crl
        crlDistributionPoints=URI:http://my.com/my.crl,URI:http://oth.com/my.crl

       Full distribution point example:

        crlDistributionPoints=crldp1_section

        [crldp1_section]

        fullname=URI:http://myhost.com/myca.crl
        CRLissuer=dirName:issuer_sect
        reasons=keyCompromise, CACompromise

        [issuer_sect]
        C=UK
        O=Organisation
        CN=Some Name

   Issuing Distribution Point
       This extension should only appear in CRLs. It is a multi valued extension whose syntax is
       similar to the "section" pointed to by the CRL distribution points extension with a few
       differences.

       The names "reasons" and "CRLissuer" are not recognized.

       The name "onlysomereasons" is accepted which sets this field. The value is in the same
       format as the CRL distribution point "reasons" field.

       The names "onlyuser", "onlyCA", "onlyAA" and "indirectCRL" are also accepted the values
       should be a boolean value (TRUE or FALSE) to indicate the value of the corresponding
       field.

       Example:

        issuingDistributionPoint=critical, @idp_section

        [idp_section]

        fullname=URI:http://myhost.com/myca.crl
        indirectCRL=TRUE
        onlysomereasons=keyCompromise, CACompromise

        [issuer_sect]
        C=UK
        O=Organisation
        CN=Some Name

   Certificate Policies.
       This is a raw extension. All the fields of this extension can be set by using the
       appropriate syntax.

       If you follow the PKIX recommendations and just using one OID then you just include the
       value of that OID. Multiple OIDs can be set separated by commas, for example:

        certificatePolicies= 1.2.4.5, 1.1.3.4

       If you wish to include qualifiers then the policy OID and qualifiers need to be specified
       in a separate section: this is done by using the @section syntax instead of a literal OID
       value.

       The section referred to must include the policy OID using the name policyIdentifier,
       cPSuri qualifiers can be included using the syntax:

        CPS.nnn=value

       userNotice qualifiers can be set using the syntax:

        userNotice.nnn=@notice

       The value of the userNotice qualifier is specified in the relevant section.  This section
       can include explicitText, organization and noticeNumbers options. explicitText and
       organization are text strings, noticeNumbers is a comma separated list of numbers. The
       organization and noticeNumbers options (if included) must BOTH be present. If you use the
       userNotice option with IE5 then you need the 'ia5org' option at the top level to modify
       the encoding: otherwise it will not be interpreted properly.

       Example:

        certificatePolicies=ia5org,1.2.3.4,1.5.6.7.8,@polsect

        [polsect]

        policyIdentifier = 1.3.5.8
        CPS.1="http://my.host.name/"
        CPS.2="http://my.your.name/"
        userNotice.1=@notice

        [notice]

        explicitText="Explicit Text Here"
        organization="Organisation Name"
        noticeNumbers=1,2,3,4

       The ia5org option changes the type of the organization field. In RFC2459 it can only be of
       type DisplayText. In RFC3280 IA5Strring is also permissible.  Some software (for example
       some versions of MSIE) may require ia5org.

   Policy Constraints
       This is a multi-valued extension which consisting of the names requireExplicitPolicy or
       inhibitPolicyMapping and a non negative intger value. At least one component must be
       present.

       Example:

        policyConstraints = requireExplicitPolicy:3

   Inhibit Any Policy
       This is a string extension whose value must be a non negative integer.

       Example:

        inhibitAnyPolicy = 2

   Name Constraints
       The name constraints extension is a multi-valued extension. The name should begin with the
       word permitted or excluded followed by a ;. The rest of the name and the value follows the
       syntax of subjectAltName except email:copy is not supported and the IP form should consist
       of an IP addresses and subnet mask separated by a /.

       Examples:

        nameConstraints=permitted;IP:192.168.0.0/255.255.0.0

        nameConstraints=permitted;email:.somedomain.com

        nameConstraints=excluded;email:.com

   OCSP No Check
       The OCSP No Check extension is a string extension but its value is ignored.

       Example:

        noCheck = ignored

DEPRECATED EXTENSIONS

       The following extensions are non standard, Netscape specific and largely obsolete. Their
       use in new applications is discouraged.

   Netscape String extensions.
       Netscape Comment (nsComment) is a string extension containing a comment which will be
       displayed when the certificate is viewed in some browsers.

       Example:

        nsComment = "Some Random Comment"

       Other supported extensions in this category are: nsBaseUrl, nsRevocationUrl,
       nsCaRevocationUrl, nsRenewalUrl, nsCaPolicyUrl and nsSslServerName.

   Netscape Certificate Type
       This is a multi-valued extensions which consists of a list of flags to be included. It was
       used to indicate the purposes for which a certificate could be used. The basicConstraints,
       keyUsage and extended key usage extensions are now used instead.

       Acceptable values for nsCertType are: client, server, email, objsign, reserved, sslCA,
       emailCA, objCA.

ARBITRARY EXTENSIONS

       If an extension is not supported by the OpenSSL code then it must be encoded using the
       arbitrary extension format. It is also possible to use the arbitrary format for supported
       extensions. Extreme care should be taken to ensure that the data is formatted correctly
       for the given extension type.

       There are two ways to encode arbitrary extensions.

       The first way is to use the word ASN1 followed by the extension content using the same
       syntax as ASN1_generate_nconf(3).  For example:

        1.2.3.4=critical,ASN1:UTF8String:Some random data

        1.2.3.4=ASN1:SEQUENCE:seq_sect

        [seq_sect]

        field1 = UTF8:field1
        field2 = UTF8:field2

       It is also possible to use the word DER to include the raw encoded data in any extension.

        1.2.3.4=critical,DER:01:02:03:04
        1.2.3.4=DER:01020304

       The value following DER is a hex dump of the DER encoding of the extension Any extension
       can be placed in this form to override the default behaviour.  For example:

        basicConstraints=critical,DER:00:01:02:03

WARNING

       There is no guarantee that a specific implementation will process a given extension. It
       may therefore be sometimes possible to use certificates for purposes prohibited by their
       extensions because a specific application does not recognize or honour the values of the
       relevant extensions.

       The DER and ASN1 options should be used with caution. It is possible to create totally
       invalid extensions if they are not used carefully.

NOTES

       If an extension is multi-value and a field value must contain a comma the long form must
       be used otherwise the comma would be misinterpreted as a field separator. For example:

        subjectAltName=URI:ldap://somehost.com/CN=foo,OU=bar

       will produce an error but the equivalent form:

        subjectAltName=@subject_alt_section

        [subject_alt_section]
        subjectAltName=URI:ldap://somehost.com/CN=foo,OU=bar

       is valid.

       Due to the behaviour of the OpenSSL conf library the same field name can only occur once
       in a section. This means that:

        subjectAltName=@alt_section

        [alt_section]

        email=steve@here
        email=steve@there

       will only recognize the last value. This can be worked around by using the form:

        [alt_section]

        email.1=steve@here
        email.2=steve@there

HISTORY

       The X509v3 extension code was first added to OpenSSL 0.9.2.

       Policy mappings, inhibit any policy and name constraints support was added in OpenSSL
       0.9.8

       The directoryName and otherName option as well as the ASN1 option for arbitrary extensions
       was added in OpenSSL 0.9.8

SEE ALSO

       req(1), ca(1), x509(1), ASN1_generate_nconf(3)