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_DSA_SIG, d2i_ECDSA_SIG, d2i_ECPKParameters,
d2i_EDIPARTYNAME, d2i_ESS_CERT_ID, d2i_ESS_CERT_ID_V2, d2i_ESS_ISSUER_SERIAL,
d2i_ESS_SIGNING_CERT, d2i_ESS_SIGNING_CERT_V2, d2i_EXTENDED_KEY_USAGE,
d2i_GENERAL_NAME, d2i_GENERAL_NAMES, d2i_IPAddressChoice, d2i_IPAddressFamily,
d2i_IPAddressOrRange, d2i_IPAddressRange, d2i_ISSUER_SIGN_TOOL,
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_OSSL_CMP_MSG,
d2i_OSSL_CMP_PKIHEADER, d2i_OSSL_CMP_PKISI, d2i_OSSL_CRMF_CERTID,
d2i_OSSL_CRMF_CERTTEMPLATE, d2i_OSSL_CRMF_ENCRYPTEDVALUE, d2i_OSSL_CRMF_MSG,
d2i_OSSL_CRMF_MSGS, d2i_OSSL_CRMF_PBMPARAMETER,
d2i_OSSL_CRMF_PKIPUBLICATIONINFO, d2i_OSSL_CRMF_SINGLEPUBINFO, 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_RSA_OAEP_PARAMS, d2i_RSA_PSS_PARAMS, 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_bio, d2i_X509_fp, 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_PUBKEY_bio, d2i_X509_PUBKEY_fp, 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_DSA_SIG,
i2d_ECDSA_SIG, i2d_ECPKParameters, i2d_EDIPARTYNAME, i2d_ESS_CERT_ID,
i2d_ESS_CERT_ID_V2, i2d_ESS_ISSUER_SERIAL, i2d_ESS_SIGNING_CERT,
i2d_ESS_SIGNING_CERT_V2, i2d_EXTENDED_KEY_USAGE, i2d_GENERAL_NAME,
i2d_GENERAL_NAMES, i2d_IPAddressChoice, i2d_IPAddressFamily,
i2d_IPAddressOrRange, i2d_IPAddressRange, i2d_ISSUER_SIGN_TOOL,
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_OSSL_CMP_MSG,
i2d_OSSL_CMP_PKIHEADER, i2d_OSSL_CMP_PKISI, i2d_OSSL_CRMF_CERTID,
i2d_OSSL_CRMF_CERTTEMPLATE, i2d_OSSL_CRMF_ENCRYPTEDVALUE, i2d_OSSL_CRMF_MSG,
i2d_OSSL_CRMF_MSGS, i2d_OSSL_CRMF_PBMPARAMETER,
i2d_OSSL_CRMF_PKIPUBLICATIONINFO, i2d_OSSL_CRMF_SINGLEPUBINFO, 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_RSA_OAEP_PARAMS, i2d_RSA_PSS_PARAMS, 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_bio, i2d_X509_fp, 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_PUBKEY_bio, i2d_X509_PUBKEY_fp, 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
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(const TYPE *a, unsigned char **ppout);
int i2d_TYPE(TYPE *a, unsigned char **ppout);
int i2d_TYPE_fp(FILE *fp, const TYPE *a);
int i2d_TYPE_fp(FILE *fp, TYPE *a);
int i2d_TYPE_bio(BIO *bp, const TYPE *a);
int i2d_TYPE_bio(BIO *bp, TYPE *a);
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. For
TYPE structures
where it matters it is possible to set up a library context on the decoded
structure this way (see the
EXAMPLES section). However using the
"reuse" capability for other purposes 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 FILE pointer
fp 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.
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.
- ECDSA_SIG
- Represents an ECDSA signature.
- 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.
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.
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 */
Setting up a library context and property query:
X509 *x;
unsigned char *buf;
const unsigned char *p;
int len;
OSSL_LIB_CTX *libctx = ....;
const char *propq = ....;
/* Set up buf and len to point to the input buffer. */
p = buf;
x = X509_new_ex(libctx, propq);
if (d2i_X509(&x, &p, len) == NULL)
/* error, x was freed and NULL assigned to it (see RETURN VALUES) */
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.
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_bio() or
i2d_TYPE_fp()) 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 1998-2023 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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>.