Updated: 2021/Apr/14


d2i_X509(3)                         OpenSSL                        d2i_X509(3)



NAME
       d2i_ACCESS_DESCRIPTION, d2i_ADMISSIONS, d2i_ADMISSION_SYNTAX,
       d2i_ASIdOrRange, d2i_ASIdentifierChoice, d2i_ASIdentifiers,
       d2i_ASN1_BIT_STRING, d2i_ASN1_BMPSTRING, d2i_ASN1_ENUMERATED,
       d2i_ASN1_GENERALIZEDTIME, d2i_ASN1_GENERALSTRING, d2i_ASN1_IA5STRING,
       d2i_ASN1_INTEGER, d2i_ASN1_NULL, d2i_ASN1_OBJECT,
       d2i_ASN1_OCTET_STRING, d2i_ASN1_PRINTABLE, d2i_ASN1_PRINTABLESTRING,
       d2i_ASN1_SEQUENCE_ANY, d2i_ASN1_SET_ANY, d2i_ASN1_T61STRING,
       d2i_ASN1_TIME, d2i_ASN1_TYPE, d2i_ASN1_UINTEGER,
       d2i_ASN1_UNIVERSALSTRING, d2i_ASN1_UTCTIME, d2i_ASN1_UTF8STRING,
       d2i_ASN1_VISIBLESTRING, d2i_ASRange, d2i_AUTHORITY_INFO_ACCESS,
       d2i_AUTHORITY_KEYID, d2i_BASIC_CONSTRAINTS, d2i_CERTIFICATEPOLICIES,
       d2i_CMS_ContentInfo, d2i_CMS_ReceiptRequest, d2i_CMS_bio,
       d2i_CRL_DIST_POINTS, d2i_DHxparams, d2i_DIRECTORYSTRING,
       d2i_DISPLAYTEXT, d2i_DIST_POINT, d2i_DIST_POINT_NAME,
       d2i_DSAPrivateKey, d2i_DSAPrivateKey_bio, d2i_DSAPrivateKey_fp,
       d2i_DSAPublicKey, d2i_DSA_PUBKEY, d2i_DSA_PUBKEY_bio,
       d2i_DSA_PUBKEY_fp, d2i_DSA_SIG, d2i_DSAparams, d2i_ECDSA_SIG,
       d2i_ECPKParameters, d2i_ECParameters, d2i_ECPrivateKey,
       d2i_ECPrivateKey_bio, d2i_ECPrivateKey_fp, d2i_EC_PUBKEY,
       d2i_EC_PUBKEY_bio, d2i_EC_PUBKEY_fp, d2i_EDIPARTYNAME, d2i_ESS_CERT_ID,
       d2i_ESS_ISSUER_SERIAL, d2i_ESS_SIGNING_CERT, d2i_EXTENDED_KEY_USAGE,
       d2i_GENERAL_NAME, d2i_GENERAL_NAMES, d2i_IPAddressChoice,
       d2i_IPAddressFamily, d2i_IPAddressOrRange, d2i_IPAddressRange,
       d2i_ISSUING_DIST_POINT, d2i_NAMING_AUTHORITY,
       d2i_NETSCAPE_CERT_SEQUENCE, d2i_NETSCAPE_SPKAC, d2i_NETSCAPE_SPKI,
       d2i_NOTICEREF, d2i_OCSP_BASICRESP, d2i_OCSP_CERTID,
       d2i_OCSP_CERTSTATUS, d2i_OCSP_CRLID, d2i_OCSP_ONEREQ, d2i_OCSP_REQINFO,
       d2i_OCSP_REQUEST, d2i_OCSP_RESPBYTES, d2i_OCSP_RESPDATA,
       d2i_OCSP_RESPID, d2i_OCSP_RESPONSE, d2i_OCSP_REVOKEDINFO,
       d2i_OCSP_SERVICELOC, d2i_OCSP_SIGNATURE, d2i_OCSP_SINGLERESP,
       d2i_OTHERNAME, d2i_PBE2PARAM, d2i_PBEPARAM, d2i_PBKDF2PARAM,
       d2i_PKCS12, d2i_PKCS12_BAGS, d2i_PKCS12_MAC_DATA, d2i_PKCS12_SAFEBAG,
       d2i_PKCS12_bio, d2i_PKCS12_fp, d2i_PKCS7, d2i_PKCS7_DIGEST,
       d2i_PKCS7_ENCRYPT, d2i_PKCS7_ENC_CONTENT, d2i_PKCS7_ENVELOPE,
       d2i_PKCS7_ISSUER_AND_SERIAL, d2i_PKCS7_RECIP_INFO, d2i_PKCS7_SIGNED,
       d2i_PKCS7_SIGNER_INFO, d2i_PKCS7_SIGN_ENVELOPE, d2i_PKCS7_bio,
       d2i_PKCS7_fp, d2i_PKCS8_PRIV_KEY_INFO, d2i_PKCS8_PRIV_KEY_INFO_bio,
       d2i_PKCS8_PRIV_KEY_INFO_fp, d2i_PKCS8_bio, d2i_PKCS8_fp,
       d2i_PKEY_USAGE_PERIOD, d2i_POLICYINFO, d2i_POLICYQUALINFO,
       d2i_PROFESSION_INFO, d2i_PROXY_CERT_INFO_EXTENSION, d2i_PROXY_POLICY,
       d2i_RSAPrivateKey, d2i_RSAPrivateKey_bio, d2i_RSAPrivateKey_fp,
       d2i_RSAPublicKey, d2i_RSAPublicKey_bio, d2i_RSAPublicKey_fp,
       d2i_RSA_OAEP_PARAMS, d2i_RSA_PSS_PARAMS, d2i_RSA_PUBKEY,
       d2i_RSA_PUBKEY_bio, d2i_RSA_PUBKEY_fp, d2i_SCRYPT_PARAMS, d2i_SCT_LIST,
       d2i_SXNET, d2i_SXNETID, d2i_TS_ACCURACY, d2i_TS_MSG_IMPRINT,
       d2i_TS_MSG_IMPRINT_bio, d2i_TS_MSG_IMPRINT_fp, d2i_TS_REQ,
       d2i_TS_REQ_bio, d2i_TS_REQ_fp, d2i_TS_RESP, d2i_TS_RESP_bio,
       d2i_TS_RESP_fp, d2i_TS_STATUS_INFO, d2i_TS_TST_INFO,
       d2i_TS_TST_INFO_bio, d2i_TS_TST_INFO_fp, d2i_USERNOTICE, d2i_X509,
       d2i_X509_ALGOR, d2i_X509_ALGORS, d2i_X509_ATTRIBUTE, d2i_X509_CERT_AUX,
       d2i_X509_CINF, d2i_X509_CRL, d2i_X509_CRL_INFO, d2i_X509_CRL_bio,
       d2i_X509_CRL_fp, d2i_X509_EXTENSION, d2i_X509_EXTENSIONS,
       d2i_X509_NAME, d2i_X509_NAME_ENTRY, d2i_X509_PUBKEY, d2i_X509_REQ,
       d2i_X509_REQ_INFO, d2i_X509_REQ_bio, d2i_X509_REQ_fp, d2i_X509_REVOKED,
       d2i_X509_SIG, d2i_X509_VAL, i2d_ACCESS_DESCRIPTION, i2d_ADMISSIONS,
       i2d_ADMISSION_SYNTAX, i2d_ASIdOrRange, i2d_ASIdentifierChoice,
       i2d_ASIdentifiers, i2d_ASN1_BIT_STRING, i2d_ASN1_BMPSTRING,
       i2d_ASN1_ENUMERATED, i2d_ASN1_GENERALIZEDTIME, i2d_ASN1_GENERALSTRING,
       i2d_ASN1_IA5STRING, i2d_ASN1_INTEGER, i2d_ASN1_NULL, i2d_ASN1_OBJECT,
       i2d_ASN1_OCTET_STRING, i2d_ASN1_PRINTABLE, i2d_ASN1_PRINTABLESTRING,
       i2d_ASN1_SEQUENCE_ANY, i2d_ASN1_SET_ANY, i2d_ASN1_T61STRING,
       i2d_ASN1_TIME, i2d_ASN1_TYPE, i2d_ASN1_UNIVERSALSTRING,
       i2d_ASN1_UTCTIME, i2d_ASN1_UTF8STRING, i2d_ASN1_VISIBLESTRING,
       i2d_ASN1_bio_stream, i2d_ASRange, i2d_AUTHORITY_INFO_ACCESS,
       i2d_AUTHORITY_KEYID, i2d_BASIC_CONSTRAINTS, i2d_CERTIFICATEPOLICIES,
       i2d_CMS_ContentInfo, i2d_CMS_ReceiptRequest, i2d_CMS_bio,
       i2d_CRL_DIST_POINTS, i2d_DHxparams, i2d_DIRECTORYSTRING,
       i2d_DISPLAYTEXT, i2d_DIST_POINT, i2d_DIST_POINT_NAME,
       i2d_DSAPrivateKey, i2d_DSAPrivateKey_bio, i2d_DSAPrivateKey_fp,
       i2d_DSAPublicKey, i2d_DSA_PUBKEY, i2d_DSA_PUBKEY_bio,
       i2d_DSA_PUBKEY_fp, i2d_DSA_SIG, i2d_DSAparams, i2d_ECDSA_SIG,
       i2d_ECPKParameters, i2d_ECParameters, i2d_ECPrivateKey,
       i2d_ECPrivateKey_bio, i2d_ECPrivateKey_fp, i2d_EC_PUBKEY,
       i2d_EC_PUBKEY_bio, i2d_EC_PUBKEY_fp, i2d_EDIPARTYNAME, i2d_ESS_CERT_ID,
       i2d_ESS_ISSUER_SERIAL, i2d_ESS_SIGNING_CERT, i2d_EXTENDED_KEY_USAGE,
       i2d_GENERAL_NAME, i2d_GENERAL_NAMES, i2d_IPAddressChoice,
       i2d_IPAddressFamily, i2d_IPAddressOrRange, i2d_IPAddressRange,
       i2d_ISSUING_DIST_POINT, i2d_NAMING_AUTHORITY,
       i2d_NETSCAPE_CERT_SEQUENCE, i2d_NETSCAPE_SPKAC, i2d_NETSCAPE_SPKI,
       i2d_NOTICEREF, i2d_OCSP_BASICRESP, i2d_OCSP_CERTID,
       i2d_OCSP_CERTSTATUS, i2d_OCSP_CRLID, i2d_OCSP_ONEREQ, i2d_OCSP_REQINFO,
       i2d_OCSP_REQUEST, i2d_OCSP_RESPBYTES, i2d_OCSP_RESPDATA,
       i2d_OCSP_RESPID, i2d_OCSP_RESPONSE, i2d_OCSP_REVOKEDINFO,
       i2d_OCSP_SERVICELOC, i2d_OCSP_SIGNATURE, i2d_OCSP_SINGLERESP,
       i2d_OTHERNAME, i2d_PBE2PARAM, i2d_PBEPARAM, i2d_PBKDF2PARAM,
       i2d_PKCS12, i2d_PKCS12_BAGS, i2d_PKCS12_MAC_DATA, i2d_PKCS12_SAFEBAG,
       i2d_PKCS12_bio, i2d_PKCS12_fp, i2d_PKCS7, i2d_PKCS7_DIGEST,
       i2d_PKCS7_ENCRYPT, i2d_PKCS7_ENC_CONTENT, i2d_PKCS7_ENVELOPE,
       i2d_PKCS7_ISSUER_AND_SERIAL, i2d_PKCS7_NDEF, i2d_PKCS7_RECIP_INFO,
       i2d_PKCS7_SIGNED, i2d_PKCS7_SIGNER_INFO, i2d_PKCS7_SIGN_ENVELOPE,
       i2d_PKCS7_bio, i2d_PKCS7_fp, i2d_PKCS8PrivateKeyInfo_bio,
       i2d_PKCS8PrivateKeyInfo_fp, i2d_PKCS8_PRIV_KEY_INFO,
       i2d_PKCS8_PRIV_KEY_INFO_bio, i2d_PKCS8_PRIV_KEY_INFO_fp, i2d_PKCS8_bio,
       i2d_PKCS8_fp, i2d_PKEY_USAGE_PERIOD, i2d_POLICYINFO,
       i2d_POLICYQUALINFO, i2d_PROFESSION_INFO, i2d_PROXY_CERT_INFO_EXTENSION,
       i2d_PROXY_POLICY, i2d_RSAPrivateKey, i2d_RSAPrivateKey_bio,
       i2d_RSAPrivateKey_fp, i2d_RSAPublicKey, i2d_RSAPublicKey_bio,
       i2d_RSAPublicKey_fp, i2d_RSA_OAEP_PARAMS, i2d_RSA_PSS_PARAMS,
       i2d_RSA_PUBKEY, i2d_RSA_PUBKEY_bio, i2d_RSA_PUBKEY_fp,
       i2d_SCRYPT_PARAMS, i2d_SCT_LIST, i2d_SXNET, i2d_SXNETID,
       i2d_TS_ACCURACY, i2d_TS_MSG_IMPRINT, i2d_TS_MSG_IMPRINT_bio,
       i2d_TS_MSG_IMPRINT_fp, i2d_TS_REQ, i2d_TS_REQ_bio, i2d_TS_REQ_fp,
       i2d_TS_RESP, i2d_TS_RESP_bio, i2d_TS_RESP_fp, i2d_TS_STATUS_INFO,
       i2d_TS_TST_INFO, i2d_TS_TST_INFO_bio, i2d_TS_TST_INFO_fp,
       i2d_USERNOTICE, i2d_X509, i2d_X509_ALGOR, i2d_X509_ALGORS,
       i2d_X509_ATTRIBUTE, i2d_X509_CERT_AUX, i2d_X509_CINF, i2d_X509_CRL,
       i2d_X509_CRL_INFO, i2d_X509_CRL_bio, i2d_X509_CRL_fp,
       i2d_X509_EXTENSION, i2d_X509_EXTENSIONS, i2d_X509_NAME,
       i2d_X509_NAME_ENTRY, i2d_X509_PUBKEY, i2d_X509_REQ, i2d_X509_REQ_INFO,
       i2d_X509_REQ_bio, i2d_X509_REQ_fp, i2d_X509_REVOKED, i2d_X509_SIG,
       i2d_X509_VAL, - convert objects from/to ASN.1/DER representation

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        TYPE *d2i_TYPE(TYPE **a, const unsigned char **ppin, long length);
        TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a);
        TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a);

        int i2d_TYPE(TYPE *a, unsigned char **ppout);
        int i2d_TYPE_fp(FILE *fp, TYPE *a);
        int i2d_TYPE_bio(BIO *bp, TYPE *a);

DESCRIPTION
       In the description here, TYPE is used a placeholder for any of the
       OpenSSL datatypes, such as X509_CRL.  The function parameters ppin and
       ppout are generally either both named pp in the headers, or in and out.

       These functions convert OpenSSL objects to and from their ASN.1/DER
       encoding.  Unlike the C structures which can have pointers to sub-
       objects within, the DER is a serialized encoding, suitable for sending
       over the network, writing to a file, and so on.

       d2i_TYPE() attempts to decode len bytes at *ppin. If successful a
       pointer to the TYPE structure is returned and *ppin is incremented to
       the byte following the parsed data.  If a is not NULL then a pointer to
       the returned structure is also written to *a.  If an error occurred
       then NULL is returned.

       On a successful return, if *a is not NULL then it is assumed that *a
       contains a valid TYPE structure and an attempt is made to reuse it.
       This "reuse" capability is present for historical compatibility but its
       use is strongly discouraged (see BUGS below, and the discussion in the
       RETURN VALUES section).

       d2i_TYPE_bio() is similar to d2i_TYPE() except it attempts to parse
       data from BIO bp.

       d2i_TYPE_fp() is similar to d2i_TYPE() except it attempts to parse data
       from FILE pointer fp.

       i2d_TYPE() encodes the structure pointed to by a into DER format.  If
       ppout is not NULL, it writes the DER encoded data to the buffer at
       *ppout, and increments it to point after the data just written.  If the
       return value is negative an error occurred, otherwise it returns the
       length of the encoded data.

       If *ppout is NULL memory will be allocated for a buffer and the encoded
       data written to it. In this case *ppout is not incremented and it
       points to the start of the data just written.

       i2d_TYPE_bio() is similar to i2d_TYPE() except it writes the encoding
       of the structure a to BIO bp and it returns 1 for success and 0 for
       failure.

       i2d_TYPE_fp() is similar to i2d_TYPE() except it writes the encoding of
       the structure a to BIO bp and it returns 1 for success and 0 for
       failure.

       These routines do not encrypt private keys and therefore offer no
       security; use PEM_write_PrivateKey(3) or similar for writing to files.

NOTES
       The letters i and d in i2d_TYPE stand for "internal" (that is, an
       internal C structure) and "DER" respectively.  So i2d_TYPE converts
       from internal to DER.

       The functions can also understand BER forms.

       The actual TYPE structure passed to i2d_TYPE() must be a valid
       populated TYPE structure -- it cannot simply be fed with an empty
       structure such as that returned by TYPE_new().

       The encoded data is in binary form and may contain embedded zeros.
       Therefore, any FILE pointers or BIOs should be opened in binary mode.
       Functions such as strlen() will not return the correct length of the
       encoded structure.

       The ways that *ppin and *ppout are incremented after the operation can
       trap the unwary. See the WARNINGS section for some common errors.  The
       reason for this-auto increment behaviour is to reflect a typical usage
       of ASN1 functions: after one structure is encoded or decoded another
       will be processed after it.

       The following points about the data types might be useful:

       ASN1_OBJECT
           Represents an ASN1 OBJECT IDENTIFIER.

       DHparams
           Represents a PKCS#3 DH parameters structure.

       DHxparams
           Represents an ANSI X9.42 DH parameters structure.

       DSA_PUBKEY
           Represents a DSA public key using a SubjectPublicKeyInfo structure.

       DSAPublicKey, DSAPrivateKey
           Use a non-standard OpenSSL format and should be avoided; use
           DSA_PUBKEY, PEM_write_PrivateKey(3), or similar instead.

       ECDSA_SIG
           Represents an ECDSA signature.

       RSAPublicKey
           Represents a PKCS#1 RSA public key structure.

       X509_ALGOR
           Represents an AlgorithmIdentifier structure as used in IETF RFC
           6960 and elsewhere.

       X509_Name
           Represents a Name type as used for subject and issuer names in IETF
           RFC 6960 and elsewhere.

       X509_REQ
           Represents a PKCS#10 certificate request.

       X509_SIG
           Represents the DigestInfo structure defined in PKCS#1 and PKCS#7.

RETURN VALUES
       d2i_TYPE(), d2i_TYPE_bio() and d2i_TYPE_fp() return a valid TYPE
       structure or NULL if an error occurs.  If the "reuse" capability has
       been used with a valid structure being passed in via a, then the object
       is freed in the event of error and *a is set to NULL.

       i2d_TYPE() returns the number of bytes successfully encoded or a
       negative value if an error occurs.

       i2d_TYPE_bio() and i2d_TYPE_fp() return 1 for success and 0 if an error
       occurs.

EXAMPLES
       Allocate and encode the DER encoding of an X509 structure:

        int len;
        unsigned char *buf;

        buf = NULL;
        len = i2d_X509(x, &buf);
        if (len < 0)
            /* error */

       Attempt to decode a buffer:

        X509 *x;
        unsigned char *buf;
        const unsigned char *p;
        int len;

        /* Set up buf and len to point to the input buffer. */
        p = buf;
        x = d2i_X509(NULL, &p, len);
        if (x == NULL)
            /* error */

       Alternative technique:

        X509 *x;
        unsigned char *buf;
        const unsigned char *p;
        int len;

        /* Set up buf and len to point to the input buffer. */
        p = buf;
        x = NULL;

        if (d2i_X509(&x, &p, len) == NULL)
            /* error */

WARNINGS
       Using a temporary variable is mandatory. A common mistake is to attempt
       to use a buffer directly as follows:

        int len;
        unsigned char *buf;

        len = i2d_X509(x, NULL);
        buf = OPENSSL_malloc(len);
        ...
        i2d_X509(x, &buf);
        ...
        OPENSSL_free(buf);

       This code will result in buf apparently containing garbage because it
       was incremented after the call to point after the data just written.
       Also buf will no longer contain the pointer allocated by
       OPENSSL_malloc() and the subsequent call to OPENSSL_free() is likely to
       crash.

       Another trap to avoid is misuse of the a argument to d2i_TYPE():

        X509 *x;

        if (d2i_X509(&x, &p, len) == NULL)
            /* error */

       This will probably crash somewhere in d2i_X509(). The reason for this
       is that the variable x is uninitialized and an attempt will be made to
       interpret its (invalid) value as an X509 structure, typically causing a
       segmentation violation. If x is set to NULL first then this will not
       happen.

BUGS
       In some versions of OpenSSL the "reuse" behaviour of d2i_TYPE() when *a
       is valid is broken and some parts of the reused structure may persist
       if they are not present in the new one. Additionally, in versions of
       OpenSSL prior to 1.1.0, when the "reuse" behaviour is used and an error
       occurs the behaviour is inconsistent. Some functions behaved as
       described here, while some did not free *a on error and did not set *a
       to NULL.

       As a result of the above issues the "reuse" behaviour is strongly
       discouraged.

       i2d_TYPE() will not return an error in many versions of OpenSSL, if
       mandatory fields are not initialized due to a programming error then
       the encoded structure may contain invalid data or omit the fields
       entirely and will not be parsed by d2i_TYPE(). This may be fixed in
       future so code should not assume that i2d_TYPE() will always succeed.

       Any function which encodes a structure (i2d_TYPE(), i2d_TYPE() or
       i2d_TYPE()) may return a stale encoding if the structure has been
       modified after deserialization or previous serialization. This is
       because some objects cache the encoding for efficiency reasons.

COPYRIGHT
       Copyright 1998-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



1.1.1i                            2020-12-10                       d2i_X509(3)