1=pod 2 3=begin comment 4 5Any keypair function here that gets deprecated should be moved to 6d2i_RSAPrivateKey.pod. 7 8=end comment 9 10=head1 NAME 11 12d2i_ACCESS_DESCRIPTION, 13d2i_ADMISSIONS, 14d2i_ADMISSION_SYNTAX, 15d2i_ASIdOrRange, 16d2i_ASIdentifierChoice, 17d2i_ASIdentifiers, 18d2i_ASN1_BIT_STRING, 19d2i_ASN1_BMPSTRING, 20d2i_ASN1_ENUMERATED, 21d2i_ASN1_GENERALIZEDTIME, 22d2i_ASN1_GENERALSTRING, 23d2i_ASN1_IA5STRING, 24d2i_ASN1_INTEGER, 25d2i_ASN1_NULL, 26d2i_ASN1_OBJECT, 27d2i_ASN1_OCTET_STRING, 28d2i_ASN1_PRINTABLE, 29d2i_ASN1_PRINTABLESTRING, 30d2i_ASN1_SEQUENCE_ANY, 31d2i_ASN1_SET_ANY, 32d2i_ASN1_T61STRING, 33d2i_ASN1_TIME, 34d2i_ASN1_TYPE, 35d2i_ASN1_UINTEGER, 36d2i_ASN1_UNIVERSALSTRING, 37d2i_ASN1_UTCTIME, 38d2i_ASN1_UTF8STRING, 39d2i_ASN1_VISIBLESTRING, 40d2i_ASRange, 41d2i_AUTHORITY_INFO_ACCESS, 42d2i_AUTHORITY_KEYID, 43d2i_BASIC_CONSTRAINTS, 44d2i_CERTIFICATEPOLICIES, 45d2i_CMS_ContentInfo, 46d2i_CMS_ReceiptRequest, 47d2i_CMS_bio, 48d2i_CRL_DIST_POINTS, 49d2i_DHxparams, 50d2i_DIRECTORYSTRING, 51d2i_DISPLAYTEXT, 52d2i_DIST_POINT, 53d2i_DIST_POINT_NAME, 54d2i_DSA_SIG, 55d2i_ECDSA_SIG, 56d2i_ECPKParameters, 57d2i_EDIPARTYNAME, 58d2i_ESS_CERT_ID, 59d2i_ESS_CERT_ID_V2, 60d2i_ESS_ISSUER_SERIAL, 61d2i_ESS_SIGNING_CERT, 62d2i_ESS_SIGNING_CERT_V2, 63d2i_EXTENDED_KEY_USAGE, 64d2i_GENERAL_NAME, 65d2i_GENERAL_NAMES, 66d2i_IPAddressChoice, 67d2i_IPAddressFamily, 68d2i_IPAddressOrRange, 69d2i_IPAddressRange, 70d2i_ISSUER_SIGN_TOOL, 71d2i_ISSUING_DIST_POINT, 72d2i_NAMING_AUTHORITY, 73d2i_NETSCAPE_CERT_SEQUENCE, 74d2i_NETSCAPE_SPKAC, 75d2i_NETSCAPE_SPKI, 76d2i_NOTICEREF, 77d2i_OCSP_BASICRESP, 78d2i_OCSP_CERTID, 79d2i_OCSP_CERTSTATUS, 80d2i_OCSP_CRLID, 81d2i_OCSP_ONEREQ, 82d2i_OCSP_REQINFO, 83d2i_OCSP_REQUEST, 84d2i_OCSP_RESPBYTES, 85d2i_OCSP_RESPDATA, 86d2i_OCSP_RESPID, 87d2i_OCSP_RESPONSE, 88d2i_OCSP_REVOKEDINFO, 89d2i_OCSP_SERVICELOC, 90d2i_OCSP_SIGNATURE, 91d2i_OCSP_SINGLERESP, 92d2i_OSSL_ATTRIBUTES_SYNTAX, 93d2i_OSSL_AUTHORITY_ATTRIBUTE_ID_SYNTAX, 94d2i_OSSL_BASIC_ATTR_CONSTRAINTS, 95d2i_OSSL_CMP_ATAVS, 96d2i_OSSL_CMP_MSG, 97d2i_OSSL_CMP_PKIHEADER, 98d2i_OSSL_CMP_PKISI, 99d2i_OSSL_CRMF_CERTID, 100d2i_OSSL_CRMF_CERTTEMPLATE, 101d2i_OSSL_CRMF_ENCRYPTEDVALUE, 102d2i_OSSL_CRMF_MSG, 103d2i_OSSL_CRMF_MSGS, 104d2i_OSSL_CRMF_PBMPARAMETER, 105d2i_OSSL_CRMF_PKIPUBLICATIONINFO, 106d2i_OSSL_CRMF_SINGLEPUBINFO, 107d2i_OSSL_IETF_ATTR_SYNTAX, 108d2i_OSSL_ISSUER_SERIAL, 109d2i_OSSL_OBJECT_DIGEST_INFO, 110d2i_OSSL_ROLE_SPEC_CERT_ID, 111d2i_OSSL_ROLE_SPEC_CERT_ID_SYNTAX, 112d2i_OSSL_TARGET_CERT, 113d2i_OSSL_TARGET, 114d2i_OSSL_TARGETING_INFORMATION, 115d2i_OSSL_TARGETS, 116d2i_OSSL_USER_NOTICE_SYNTAX, 117d2i_OTHERNAME, 118d2i_PBE2PARAM, 119d2i_PBEPARAM, 120d2i_PBKDF2PARAM, 121d2i_PBMAC1PARAM, 122d2i_PKCS12, 123d2i_PKCS12_BAGS, 124d2i_PKCS12_MAC_DATA, 125d2i_PKCS12_SAFEBAG, 126d2i_PKCS12_bio, 127d2i_PKCS12_fp, 128d2i_PKCS7, 129d2i_PKCS7_DIGEST, 130d2i_PKCS7_ENCRYPT, 131d2i_PKCS7_ENC_CONTENT, 132d2i_PKCS7_ENVELOPE, 133d2i_PKCS7_ISSUER_AND_SERIAL, 134d2i_PKCS7_RECIP_INFO, 135d2i_PKCS7_SIGNED, 136d2i_PKCS7_SIGNER_INFO, 137d2i_PKCS7_SIGN_ENVELOPE, 138d2i_PKCS7_bio, 139d2i_PKCS7_fp, 140d2i_PKCS8_PRIV_KEY_INFO, 141d2i_PKCS8_PRIV_KEY_INFO_bio, 142d2i_PKCS8_PRIV_KEY_INFO_fp, 143d2i_PKCS8_bio, 144d2i_PKCS8_fp, 145d2i_PKEY_USAGE_PERIOD, 146d2i_POLICYINFO, 147d2i_POLICYQUALINFO, 148d2i_PROFESSION_INFO, 149d2i_PROXY_CERT_INFO_EXTENSION, 150d2i_PROXY_POLICY, 151d2i_RSA_OAEP_PARAMS, 152d2i_RSA_PSS_PARAMS, 153d2i_SCRYPT_PARAMS, 154d2i_SCT_LIST, 155d2i_SXNET, 156d2i_SXNETID, 157d2i_TS_ACCURACY, 158d2i_TS_MSG_IMPRINT, 159d2i_TS_MSG_IMPRINT_bio, 160d2i_TS_MSG_IMPRINT_fp, 161d2i_TS_REQ, 162d2i_TS_REQ_bio, 163d2i_TS_REQ_fp, 164d2i_TS_RESP, 165d2i_TS_RESP_bio, 166d2i_TS_RESP_fp, 167d2i_TS_STATUS_INFO, 168d2i_TS_TST_INFO, 169d2i_TS_TST_INFO_bio, 170d2i_TS_TST_INFO_fp, 171d2i_USERNOTICE, 172d2i_X509, 173d2i_X509_bio, 174d2i_X509_fp, 175d2i_X509_ACERT, 176d2i_X509_ACERT_bio, 177d2i_X509_ACERT_fp, 178d2i_X509_ALGOR, 179d2i_X509_ALGORS, 180d2i_X509_ATTRIBUTE, 181d2i_X509_CERT_AUX, 182d2i_X509_CINF, 183d2i_X509_CRL, 184d2i_X509_CRL_INFO, 185d2i_X509_CRL_bio, 186d2i_X509_CRL_fp, 187d2i_X509_EXTENSION, 188d2i_X509_EXTENSIONS, 189d2i_X509_NAME, 190d2i_X509_NAME_ENTRY, 191d2i_X509_PUBKEY, 192d2i_X509_PUBKEY_bio, 193d2i_X509_PUBKEY_fp, 194d2i_X509_REQ, 195d2i_X509_REQ_INFO, 196d2i_X509_REQ_bio, 197d2i_X509_REQ_fp, 198d2i_X509_REVOKED, 199d2i_X509_SIG, 200d2i_X509_VAL, 201i2d_ACCESS_DESCRIPTION, 202i2d_ADMISSIONS, 203i2d_ADMISSION_SYNTAX, 204i2d_ASIdOrRange, 205i2d_ASIdentifierChoice, 206i2d_ASIdentifiers, 207i2d_ASN1_BIT_STRING, 208i2d_ASN1_BMPSTRING, 209i2d_ASN1_ENUMERATED, 210i2d_ASN1_GENERALIZEDTIME, 211i2d_ASN1_GENERALSTRING, 212i2d_ASN1_IA5STRING, 213i2d_ASN1_INTEGER, 214i2d_ASN1_NULL, 215i2d_ASN1_OBJECT, 216i2d_ASN1_OCTET_STRING, 217i2d_ASN1_PRINTABLE, 218i2d_ASN1_PRINTABLESTRING, 219i2d_ASN1_SEQUENCE_ANY, 220i2d_ASN1_SET_ANY, 221i2d_ASN1_T61STRING, 222i2d_ASN1_TIME, 223i2d_ASN1_TYPE, 224i2d_ASN1_UNIVERSALSTRING, 225i2d_ASN1_UTCTIME, 226i2d_ASN1_UTF8STRING, 227i2d_ASN1_VISIBLESTRING, 228i2d_ASN1_bio_stream, 229i2d_ASRange, 230i2d_AUTHORITY_INFO_ACCESS, 231i2d_AUTHORITY_KEYID, 232i2d_BASIC_CONSTRAINTS, 233i2d_CERTIFICATEPOLICIES, 234i2d_CMS_ContentInfo, 235i2d_CMS_ReceiptRequest, 236i2d_CMS_bio, 237i2d_CRL_DIST_POINTS, 238i2d_DHxparams, 239i2d_DIRECTORYSTRING, 240i2d_DISPLAYTEXT, 241i2d_DIST_POINT, 242i2d_DIST_POINT_NAME, 243i2d_DSA_SIG, 244i2d_ECDSA_SIG, 245i2d_ECPKParameters, 246i2d_EDIPARTYNAME, 247i2d_ESS_CERT_ID, 248i2d_ESS_CERT_ID_V2, 249i2d_ESS_ISSUER_SERIAL, 250i2d_ESS_SIGNING_CERT, 251i2d_ESS_SIGNING_CERT_V2, 252i2d_EXTENDED_KEY_USAGE, 253i2d_GENERAL_NAME, 254i2d_GENERAL_NAMES, 255i2d_IPAddressChoice, 256i2d_IPAddressFamily, 257i2d_IPAddressOrRange, 258i2d_IPAddressRange, 259i2d_ISSUER_SIGN_TOOL, 260i2d_ISSUING_DIST_POINT, 261i2d_NAMING_AUTHORITY, 262i2d_NETSCAPE_CERT_SEQUENCE, 263i2d_NETSCAPE_SPKAC, 264i2d_NETSCAPE_SPKI, 265i2d_NOTICEREF, 266i2d_OCSP_BASICRESP, 267i2d_OCSP_CERTID, 268i2d_OCSP_CERTSTATUS, 269i2d_OCSP_CRLID, 270i2d_OCSP_ONEREQ, 271i2d_OCSP_REQINFO, 272i2d_OCSP_REQUEST, 273i2d_OCSP_RESPBYTES, 274i2d_OCSP_RESPDATA, 275i2d_OCSP_RESPID, 276i2d_OCSP_RESPONSE, 277i2d_OCSP_REVOKEDINFO, 278i2d_OCSP_SERVICELOC, 279i2d_OCSP_SIGNATURE, 280i2d_OCSP_SINGLERESP, 281i2d_OSSL_ATTRIBUTES_SYNTAX, 282i2d_OSSL_AUTHORITY_ATTRIBUTE_ID_SYNTAX, 283i2d_OSSL_BASIC_ATTR_CONSTRAINTS, 284i2d_OSSL_CMP_ATAVS, 285i2d_OSSL_CMP_MSG, 286i2d_OSSL_CMP_PKIHEADER, 287i2d_OSSL_CMP_PKISI, 288i2d_OSSL_CRMF_CERTID, 289i2d_OSSL_CRMF_CERTTEMPLATE, 290i2d_OSSL_CRMF_ENCRYPTEDVALUE, 291i2d_OSSL_CRMF_MSG, 292i2d_OSSL_CRMF_MSGS, 293i2d_OSSL_CRMF_PBMPARAMETER, 294i2d_OSSL_CRMF_PKIPUBLICATIONINFO, 295i2d_OSSL_CRMF_SINGLEPUBINFO, 296i2d_OSSL_IETF_ATTR_SYNTAX, 297i2d_OSSL_ISSUER_SERIAL, 298i2d_OSSL_OBJECT_DIGEST_INFO, 299i2d_OSSL_ROLE_SPEC_CERT_ID, 300i2d_OSSL_ROLE_SPEC_CERT_ID_SYNTAX, 301i2d_OSSL_TARGET_CERT, 302i2d_OSSL_TARGET, 303i2d_OSSL_TARGETING_INFORMATION, 304i2d_OSSL_TARGETS, 305i2d_OSSL_USER_NOTICE_SYNTAX, 306i2d_OTHERNAME, 307i2d_PBE2PARAM, 308i2d_PBEPARAM, 309i2d_PBKDF2PARAM, 310i2d_PBMAC1PARAM, 311i2d_PKCS12, 312i2d_PKCS12_BAGS, 313i2d_PKCS12_MAC_DATA, 314i2d_PKCS12_SAFEBAG, 315i2d_PKCS12_bio, 316i2d_PKCS12_fp, 317i2d_PKCS7, 318i2d_PKCS7_DIGEST, 319i2d_PKCS7_ENCRYPT, 320i2d_PKCS7_ENC_CONTENT, 321i2d_PKCS7_ENVELOPE, 322i2d_PKCS7_ISSUER_AND_SERIAL, 323i2d_PKCS7_NDEF, 324i2d_PKCS7_RECIP_INFO, 325i2d_PKCS7_SIGNED, 326i2d_PKCS7_SIGNER_INFO, 327i2d_PKCS7_SIGN_ENVELOPE, 328i2d_PKCS7_bio, 329i2d_PKCS7_fp, 330i2d_PKCS8PrivateKeyInfo_bio, 331i2d_PKCS8PrivateKeyInfo_fp, 332i2d_PKCS8_PRIV_KEY_INFO, 333i2d_PKCS8_PRIV_KEY_INFO_bio, 334i2d_PKCS8_PRIV_KEY_INFO_fp, 335i2d_PKCS8_bio, 336i2d_PKCS8_fp, 337i2d_PKEY_USAGE_PERIOD, 338i2d_POLICYINFO, 339i2d_POLICYQUALINFO, 340i2d_PROFESSION_INFO, 341i2d_PROXY_CERT_INFO_EXTENSION, 342i2d_PROXY_POLICY, 343i2d_RSA_OAEP_PARAMS, 344i2d_RSA_PSS_PARAMS, 345i2d_SCRYPT_PARAMS, 346i2d_SCT_LIST, 347i2d_SXNET, 348i2d_SXNETID, 349i2d_TS_ACCURACY, 350i2d_TS_MSG_IMPRINT, 351i2d_TS_MSG_IMPRINT_bio, 352i2d_TS_MSG_IMPRINT_fp, 353i2d_TS_REQ, 354i2d_TS_REQ_bio, 355i2d_TS_REQ_fp, 356i2d_TS_RESP, 357i2d_TS_RESP_bio, 358i2d_TS_RESP_fp, 359i2d_TS_STATUS_INFO, 360i2d_TS_TST_INFO, 361i2d_TS_TST_INFO_bio, 362i2d_TS_TST_INFO_fp, 363i2d_USERNOTICE, 364i2d_X509, 365i2d_X509_bio, 366i2d_X509_fp, 367i2d_X509_ACERT, 368i2d_X509_ACERT_bio, 369i2d_X509_ACERT_fp, 370i2d_X509_ALGOR, 371i2d_X509_ALGORS, 372i2d_X509_ATTRIBUTE, 373i2d_X509_CERT_AUX, 374i2d_X509_CINF, 375i2d_X509_CRL, 376i2d_X509_CRL_INFO, 377i2d_X509_CRL_bio, 378i2d_X509_CRL_fp, 379i2d_X509_EXTENSION, 380i2d_X509_EXTENSIONS, 381i2d_X509_NAME, 382i2d_X509_NAME_ENTRY, 383i2d_X509_PUBKEY, 384i2d_X509_PUBKEY_bio, 385i2d_X509_PUBKEY_fp, 386i2d_X509_REQ, 387i2d_X509_REQ_INFO, 388i2d_X509_REQ_bio, 389i2d_X509_REQ_fp, 390i2d_X509_REVOKED, 391i2d_X509_SIG, 392i2d_X509_VAL, 393- convert objects from/to ASN.1/DER representation 394 395=head1 SYNOPSIS 396 397=for openssl generic 398 399 TYPE *d2i_TYPE(TYPE **a, const unsigned char **ppin, long length); 400 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a); 401 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a); 402 403 int i2d_TYPE(const TYPE *a, unsigned char **ppout); 404 int i2d_TYPE(TYPE *a, unsigned char **ppout); 405 int i2d_TYPE_fp(FILE *fp, const TYPE *a); 406 int i2d_TYPE_fp(FILE *fp, TYPE *a); 407 int i2d_TYPE_bio(BIO *bp, const TYPE *a); 408 int i2d_TYPE_bio(BIO *bp, TYPE *a); 409 410=head1 DESCRIPTION 411 412In the description here, B<I<TYPE>> is used a placeholder 413for any of the OpenSSL datatypes, such as B<X509_CRL>. 414The function parameters I<ppin> and I<ppout> are generally 415either both named I<pp> in the headers, or I<in> and I<out>. 416 417These functions convert OpenSSL objects to and from their ASN.1/DER 418encoding. Unlike the C structures which can have pointers to sub-objects 419within, the DER is a serialized encoding, suitable for sending over the 420network, writing to a file, and so on. 421 422B<d2i_I<TYPE>>() attempts to decode I<len> bytes at I<*ppin>. If successful a 423pointer to the B<I<TYPE>> structure is returned and I<*ppin> is incremented to 424the byte following the parsed data. If I<a> is not NULL then a pointer 425to the returned structure is also written to I<*a>. If an error occurred 426then NULL is returned. The caller retains ownership of the 427returned object and needs to free it when it is no longer needed, e.g. 428using X509_free() for X509 objects or DSA_SIG_free() for DSA_SIG objects. 429 430On a successful return, if I<*a> is not NULL then it is assumed that I<*a> 431contains a valid B<I<TYPE>> structure and an attempt is made to reuse it. 432For B<I<TYPE>> structures where it matters it is possible to set up a library 433context on the decoded structure this way (see the B<EXAMPLES> section). 434However using the "reuse" capability for other purposes is B<strongly 435discouraged> (see B<BUGS> below, and the discussion in the B<RETURN VALUES> 436section). 437 438B<d2i_I<TYPE>_bio>() is similar to B<d2i_I<TYPE>>() except it attempts 439to parse data from BIO I<bp>. 440 441B<d2i_I<TYPE>_fp>() is similar to B<d2i_I<TYPE>>() except it attempts 442to parse data from FILE pointer I<fp>. 443 444B<i2d_I<TYPE>>() encodes the structure pointed to by I<a> into DER format. 445If I<ppout> is not NULL, it writes the DER encoded data to the buffer 446at I<*ppout>, and increments it to point after the data just written. 447If the return value is negative an error occurred, otherwise it 448returns the length of the encoded data. 449 450If I<*ppout> is NULL memory will be allocated for a buffer and the encoded 451data written to it. In this case I<*ppout> is not incremented and it points 452to the start of the data just written. 453 454B<i2d_I<TYPE>_bio>() is similar to B<i2d_I<TYPE>>() except it writes 455the encoding of the structure I<a> to BIO I<bp> and it 456returns 1 for success and 0 for failure. 457 458B<i2d_I<TYPE>_fp>() is similar to B<i2d_I<TYPE>>() except it writes 459the encoding of the structure I<a> to FILE pointer I<fp> and it 460returns 1 for success and 0 for failure. 461 462These routines do not encrypt private keys and therefore offer no 463security; use L<PEM_write_PrivateKey(3)> or similar for writing to files. 464 465=head1 NOTES 466 467The letters B<i> and B<d> in B<i2d_I<TYPE>>() stand for 468"internal" (that is, an internal C structure) and "DER" respectively. 469So B<i2d_I<TYPE>>() converts from internal to DER. 470 471The functions can also understand B<BER> forms. 472 473The actual TYPE structure passed to B<i2d_I<TYPE>>() must be a valid 474populated B<I<TYPE>> structure -- it B<cannot> simply be fed with an 475empty structure such as that returned by TYPE_new(). 476 477The encoded data is in binary form and may contain embedded zeros. 478Therefore, any FILE pointers or BIOs should be opened in binary mode. 479Functions such as strlen() will B<not> return the correct length 480of the encoded structure. 481 482The ways that I<*ppin> and I<*ppout> are incremented after the operation 483can trap the unwary. See the B<WARNINGS> section for some common 484errors. 485The reason for this-auto increment behaviour is to reflect a typical 486usage of ASN1 functions: after one structure is encoded or decoded 487another will be processed after it. 488 489The following points about the data types might be useful: 490 491=over 4 492 493=item B<ASN1_OBJECT> 494 495Represents an ASN1 OBJECT IDENTIFIER. 496 497=item B<DHparams> 498 499Represents a PKCS#3 DH parameters structure. 500 501=item B<DHxparams> 502 503Represents an ANSI X9.42 DH parameters structure. 504 505=item B<ECDSA_SIG> 506 507Represents an ECDSA signature. 508 509=item B<X509_ALGOR> 510 511Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and 512elsewhere. 513 514=item B<X509_NAME> 515 516Represents a B<Name> type as used for subject and issuer names in 517IETF RFC 6960 and elsewhere. 518 519=item B<X509_REQ> 520 521Represents a PKCS#10 certificate request. 522 523=item B<X509_SIG> 524 525Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7. 526 527=back 528 529=head1 RETURN VALUES 530 531B<d2i_I<TYPE>>(), B<d2i_I<TYPE>_bio>() and B<d2i_I<TYPE>_fp>() return a valid 532B<I<TYPE>> structure or NULL if an error occurs. If the "reuse" capability has 533been used with a valid structure being passed in via I<a>, then the object is 534freed in the event of error and I<*a> is set to NULL. 535 536B<i2d_I<TYPE>>() returns the number of bytes successfully encoded or a negative 537value if an error occurs. 538 539B<i2d_I<TYPE>_bio>() and B<i2d_I<TYPE>_fp>() return 1 for success and 0 if an 540error occurs. 541 542=head1 EXAMPLES 543 544Allocate and encode the DER encoding of an X509 structure: 545 546 int len; 547 unsigned char *buf; 548 549 buf = NULL; 550 len = i2d_X509(x, &buf); 551 if (len < 0) 552 /* error */ 553 554Attempt to decode a buffer: 555 556 X509 *x; 557 unsigned char *buf; 558 const unsigned char *p; 559 int len; 560 561 /* Set up buf and len to point to the input buffer. */ 562 p = buf; 563 x = d2i_X509(NULL, &p, len); 564 if (x == NULL) 565 /* error */ 566 567Alternative technique: 568 569 X509 *x; 570 unsigned char *buf; 571 const unsigned char *p; 572 int len; 573 574 /* Set up buf and len to point to the input buffer. */ 575 p = buf; 576 x = NULL; 577 578 if (d2i_X509(&x, &p, len) == NULL) 579 /* error */ 580 581Setting up a library context and property query: 582 583 X509 *x; 584 unsigned char *buf; 585 const unsigned char *p; 586 int len; 587 OSSL_LIB_CTX *libctx = ....; 588 const char *propq = ....; 589 590 /* Set up buf and len to point to the input buffer. */ 591 p = buf; 592 x = X509_new_ex(libctx, propq); 593 594 if (d2i_X509(&x, &p, len) == NULL) 595 /* error, x was freed and NULL assigned to it (see RETURN VALUES) */ 596 597=head1 WARNINGS 598 599Using a temporary variable is mandatory. A common 600mistake is to attempt to use a buffer directly as follows: 601 602 int len; 603 unsigned char *buf; 604 605 len = i2d_X509(x, NULL); 606 buf = OPENSSL_malloc(len); 607 ... 608 i2d_X509(x, &buf); 609 ... 610 OPENSSL_free(buf); 611 612This code will result in I<buf> apparently containing garbage because 613it was incremented after the call to point after the data just written. 614Also I<buf> will no longer contain the pointer allocated by OPENSSL_malloc() 615and the subsequent call to OPENSSL_free() is likely to crash. 616 617Another trap to avoid is misuse of the I<a> argument to B<d2i_I<TYPE>>(): 618 619 X509 *x; 620 621 if (d2i_X509(&x, &p, len) == NULL) 622 /* error */ 623 624This will probably crash somewhere in d2i_X509(). The reason for this 625is that the variable I<x> is uninitialized and an attempt will be made to 626interpret its (invalid) value as an B<X509> structure, typically causing 627a segmentation violation. If I<x> is set to NULL first then this will not 628happen. 629 630=head1 BUGS 631 632In some versions of OpenSSL the "reuse" behaviour of B<d2i_I<TYPE>>() when 633I<*a> is valid is broken and some parts of the reused structure may 634persist if they are not present in the new one. Additionally, in versions of 635OpenSSL prior to 1.1.0, when the "reuse" behaviour is used and an error occurs 636the behaviour is inconsistent. Some functions behaved as described here, while 637some did not free I<*a> on error and did not set I<*a> to NULL. 638 639As a result of the above issues the "reuse" behaviour is strongly discouraged. 640 641B<i2d_I<TYPE>>() will not return an error in many versions of OpenSSL, 642if mandatory fields are not initialized due to a programming error 643then the encoded structure may contain invalid data or omit the 644fields entirely and will not be parsed by B<d2i_I<TYPE>>(). This may be 645fixed in future so code should not assume that B<i2d_I<TYPE>>() will 646always succeed. 647 648Any function which encodes a structure (B<i2d_I<TYPE>>(), 649B<i2d_I<TYPE>_bio>() or B<i2d_I<TYPE>_fp>()) may return a stale encoding if the 650structure has been modified after deserialization or previous 651serialization. This is because some objects cache the encoding for 652efficiency reasons. 653 654=head1 COPYRIGHT 655 656Copyright 1998-2024 The OpenSSL Project Authors. All Rights Reserved. 657 658Licensed under the Apache License 2.0 (the "License"). You may not use 659this file except in compliance with the License. You can obtain a copy 660in the file LICENSE in the source distribution or at 661L<https://www.openssl.org/source/license.html>. 662 663=cut 664
