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_ATTRIBUTES_SYNTAX, 42d2i_AUTHORITY_INFO_ACCESS, 43d2i_AUTHORITY_KEYID, 44d2i_BASIC_CONSTRAINTS, 45d2i_CERTIFICATEPOLICIES, 46d2i_CMS_ContentInfo, 47d2i_CMS_ReceiptRequest, 48d2i_CMS_bio, 49d2i_CRL_DIST_POINTS, 50d2i_DHxparams, 51d2i_DIRECTORYSTRING, 52d2i_DISPLAYTEXT, 53d2i_DIST_POINT, 54d2i_DIST_POINT_NAME, 55d2i_DSA_SIG, 56d2i_ECDSA_SIG, 57d2i_ECPKParameters, 58d2i_EDIPARTYNAME, 59d2i_ESS_CERT_ID, 60d2i_ESS_CERT_ID_V2, 61d2i_ESS_ISSUER_SERIAL, 62d2i_ESS_SIGNING_CERT, 63d2i_ESS_SIGNING_CERT_V2, 64d2i_EXTENDED_KEY_USAGE, 65d2i_GENERAL_NAME, 66d2i_GENERAL_NAMES, 67d2i_IPAddressChoice, 68d2i_IPAddressFamily, 69d2i_IPAddressOrRange, 70d2i_IPAddressRange, 71d2i_ISSUER_SIGN_TOOL, 72d2i_ISSUING_DIST_POINT, 73d2i_NAMING_AUTHORITY, 74d2i_NETSCAPE_CERT_SEQUENCE, 75d2i_NETSCAPE_SPKAC, 76d2i_NETSCAPE_SPKI, 77d2i_NOTICEREF, 78d2i_OCSP_BASICRESP, 79d2i_OCSP_CERTID, 80d2i_OCSP_CERTSTATUS, 81d2i_OCSP_CRLID, 82d2i_OCSP_ONEREQ, 83d2i_OCSP_REQINFO, 84d2i_OCSP_REQUEST, 85d2i_OCSP_RESPBYTES, 86d2i_OCSP_RESPDATA, 87d2i_OCSP_RESPID, 88d2i_OCSP_RESPONSE, 89d2i_OCSP_REVOKEDINFO, 90d2i_OCSP_SERVICELOC, 91d2i_OCSP_SIGNATURE, 92d2i_OCSP_SINGLERESP, 93d2i_OSSL_CMP_ATAVS, 94d2i_OSSL_CMP_MSG, 95d2i_OSSL_CMP_PKIHEADER, 96d2i_OSSL_CMP_PKISI, 97d2i_OSSL_CRMF_CERTID, 98d2i_OSSL_CRMF_CERTTEMPLATE, 99d2i_OSSL_CRMF_ENCRYPTEDVALUE, 100d2i_OSSL_CRMF_MSG, 101d2i_OSSL_CRMF_MSGS, 102d2i_OSSL_CRMF_PBMPARAMETER, 103d2i_OSSL_CRMF_PKIPUBLICATIONINFO, 104d2i_OSSL_CRMF_SINGLEPUBINFO, 105d2i_OSSL_IETF_ATTR_SYNTAX, 106d2i_OSSL_ISSUER_SERIAL, 107d2i_OSSL_OBJECT_DIGEST_INFO, 108d2i_OSSL_TARGET_CERT, 109d2i_OSSL_TARGET, 110d2i_OSSL_TARGETING_INFORMATION, 111d2i_OSSL_TARGETS, 112d2i_OTHERNAME, 113d2i_PBE2PARAM, 114d2i_PBEPARAM, 115d2i_PBKDF2PARAM, 116d2i_PKCS12, 117d2i_PKCS12_BAGS, 118d2i_PKCS12_MAC_DATA, 119d2i_PKCS12_SAFEBAG, 120d2i_PKCS12_bio, 121d2i_PKCS12_fp, 122d2i_PKCS7, 123d2i_PKCS7_DIGEST, 124d2i_PKCS7_ENCRYPT, 125d2i_PKCS7_ENC_CONTENT, 126d2i_PKCS7_ENVELOPE, 127d2i_PKCS7_ISSUER_AND_SERIAL, 128d2i_PKCS7_RECIP_INFO, 129d2i_PKCS7_SIGNED, 130d2i_PKCS7_SIGNER_INFO, 131d2i_PKCS7_SIGN_ENVELOPE, 132d2i_PKCS7_bio, 133d2i_PKCS7_fp, 134d2i_PKCS8_PRIV_KEY_INFO, 135d2i_PKCS8_PRIV_KEY_INFO_bio, 136d2i_PKCS8_PRIV_KEY_INFO_fp, 137d2i_PKCS8_bio, 138d2i_PKCS8_fp, 139d2i_PKEY_USAGE_PERIOD, 140d2i_POLICYINFO, 141d2i_POLICYQUALINFO, 142d2i_PROFESSION_INFO, 143d2i_PROXY_CERT_INFO_EXTENSION, 144d2i_PROXY_POLICY, 145d2i_RSA_OAEP_PARAMS, 146d2i_RSA_PSS_PARAMS, 147d2i_SCRYPT_PARAMS, 148d2i_SCT_LIST, 149d2i_SXNET, 150d2i_SXNETID, 151d2i_TS_ACCURACY, 152d2i_TS_MSG_IMPRINT, 153d2i_TS_MSG_IMPRINT_bio, 154d2i_TS_MSG_IMPRINT_fp, 155d2i_TS_REQ, 156d2i_TS_REQ_bio, 157d2i_TS_REQ_fp, 158d2i_TS_RESP, 159d2i_TS_RESP_bio, 160d2i_TS_RESP_fp, 161d2i_TS_STATUS_INFO, 162d2i_TS_TST_INFO, 163d2i_TS_TST_INFO_bio, 164d2i_TS_TST_INFO_fp, 165d2i_USERNOTICE, 166d2i_X509, 167d2i_X509_bio, 168d2i_X509_fp, 169d2i_X509_ACERT, 170d2i_X509_ACERT_bio, 171d2i_X509_ACERT_fp, 172d2i_X509_ALGOR, 173d2i_X509_ALGORS, 174d2i_X509_ATTRIBUTE, 175d2i_X509_CERT_AUX, 176d2i_X509_CINF, 177d2i_X509_CRL, 178d2i_X509_CRL_INFO, 179d2i_X509_CRL_bio, 180d2i_X509_CRL_fp, 181d2i_X509_EXTENSION, 182d2i_X509_EXTENSIONS, 183d2i_X509_NAME, 184d2i_X509_NAME_ENTRY, 185d2i_X509_PUBKEY, 186d2i_X509_PUBKEY_bio, 187d2i_X509_PUBKEY_fp, 188d2i_X509_REQ, 189d2i_X509_REQ_INFO, 190d2i_X509_REQ_bio, 191d2i_X509_REQ_fp, 192d2i_X509_REVOKED, 193d2i_X509_SIG, 194d2i_X509_VAL, 195i2d_ACCESS_DESCRIPTION, 196i2d_ADMISSIONS, 197i2d_ADMISSION_SYNTAX, 198i2d_ASIdOrRange, 199i2d_ASIdentifierChoice, 200i2d_ASIdentifiers, 201i2d_ASN1_BIT_STRING, 202i2d_ASN1_BMPSTRING, 203i2d_ASN1_ENUMERATED, 204i2d_ASN1_GENERALIZEDTIME, 205i2d_ASN1_GENERALSTRING, 206i2d_ASN1_IA5STRING, 207i2d_ASN1_INTEGER, 208i2d_ASN1_NULL, 209i2d_ASN1_OBJECT, 210i2d_ASN1_OCTET_STRING, 211i2d_ASN1_PRINTABLE, 212i2d_ASN1_PRINTABLESTRING, 213i2d_ASN1_SEQUENCE_ANY, 214i2d_ASN1_SET_ANY, 215i2d_ASN1_T61STRING, 216i2d_ASN1_TIME, 217i2d_ASN1_TYPE, 218i2d_ASN1_UNIVERSALSTRING, 219i2d_ASN1_UTCTIME, 220i2d_ASN1_UTF8STRING, 221i2d_ASN1_VISIBLESTRING, 222i2d_ASN1_bio_stream, 223i2d_ASRange, 224i2d_ATTRIBUTES_SYNTAX, 225i2d_AUTHORITY_INFO_ACCESS, 226i2d_AUTHORITY_KEYID, 227i2d_BASIC_CONSTRAINTS, 228i2d_CERTIFICATEPOLICIES, 229i2d_CMS_ContentInfo, 230i2d_CMS_ReceiptRequest, 231i2d_CMS_bio, 232i2d_CRL_DIST_POINTS, 233i2d_DHxparams, 234i2d_DIRECTORYSTRING, 235i2d_DISPLAYTEXT, 236i2d_DIST_POINT, 237i2d_DIST_POINT_NAME, 238i2d_DSA_SIG, 239i2d_ECDSA_SIG, 240i2d_ECPKParameters, 241i2d_EDIPARTYNAME, 242i2d_ESS_CERT_ID, 243i2d_ESS_CERT_ID_V2, 244i2d_ESS_ISSUER_SERIAL, 245i2d_ESS_SIGNING_CERT, 246i2d_ESS_SIGNING_CERT_V2, 247i2d_EXTENDED_KEY_USAGE, 248i2d_GENERAL_NAME, 249i2d_GENERAL_NAMES, 250i2d_IPAddressChoice, 251i2d_IPAddressFamily, 252i2d_IPAddressOrRange, 253i2d_IPAddressRange, 254i2d_ISSUER_SIGN_TOOL, 255i2d_ISSUING_DIST_POINT, 256i2d_NAMING_AUTHORITY, 257i2d_NETSCAPE_CERT_SEQUENCE, 258i2d_NETSCAPE_SPKAC, 259i2d_NETSCAPE_SPKI, 260i2d_NOTICEREF, 261i2d_OCSP_BASICRESP, 262i2d_OCSP_CERTID, 263i2d_OCSP_CERTSTATUS, 264i2d_OCSP_CRLID, 265i2d_OCSP_ONEREQ, 266i2d_OCSP_REQINFO, 267i2d_OCSP_REQUEST, 268i2d_OCSP_RESPBYTES, 269i2d_OCSP_RESPDATA, 270i2d_OCSP_RESPID, 271i2d_OCSP_RESPONSE, 272i2d_OCSP_REVOKEDINFO, 273i2d_OCSP_SERVICELOC, 274i2d_OCSP_SIGNATURE, 275i2d_OCSP_SINGLERESP, 276i2d_OSSL_CMP_ATAVS, 277i2d_OSSL_CMP_MSG, 278i2d_OSSL_CMP_PKIHEADER, 279i2d_OSSL_CMP_PKISI, 280i2d_OSSL_CRMF_CERTID, 281i2d_OSSL_CRMF_CERTTEMPLATE, 282i2d_OSSL_CRMF_ENCRYPTEDVALUE, 283i2d_OSSL_CRMF_MSG, 284i2d_OSSL_CRMF_MSGS, 285i2d_OSSL_CRMF_PBMPARAMETER, 286i2d_OSSL_CRMF_PKIPUBLICATIONINFO, 287i2d_OSSL_CRMF_SINGLEPUBINFO, 288i2d_OSSL_IETF_ATTR_SYNTAX, 289i2d_OSSL_ISSUER_SERIAL, 290i2d_OSSL_OBJECT_DIGEST_INFO, 291i2d_OSSL_TARGET_CERT, 292i2d_OSSL_TARGET, 293i2d_OSSL_TARGETING_INFORMATION, 294i2d_OSSL_TARGETS, 295i2d_OTHERNAME, 296i2d_PBE2PARAM, 297i2d_PBEPARAM, 298i2d_PBKDF2PARAM, 299i2d_PKCS12, 300i2d_PKCS12_BAGS, 301i2d_PKCS12_MAC_DATA, 302i2d_PKCS12_SAFEBAG, 303i2d_PKCS12_bio, 304i2d_PKCS12_fp, 305i2d_PKCS7, 306i2d_PKCS7_DIGEST, 307i2d_PKCS7_ENCRYPT, 308i2d_PKCS7_ENC_CONTENT, 309i2d_PKCS7_ENVELOPE, 310i2d_PKCS7_ISSUER_AND_SERIAL, 311i2d_PKCS7_NDEF, 312i2d_PKCS7_RECIP_INFO, 313i2d_PKCS7_SIGNED, 314i2d_PKCS7_SIGNER_INFO, 315i2d_PKCS7_SIGN_ENVELOPE, 316i2d_PKCS7_bio, 317i2d_PKCS7_fp, 318i2d_PKCS8PrivateKeyInfo_bio, 319i2d_PKCS8PrivateKeyInfo_fp, 320i2d_PKCS8_PRIV_KEY_INFO, 321i2d_PKCS8_PRIV_KEY_INFO_bio, 322i2d_PKCS8_PRIV_KEY_INFO_fp, 323i2d_PKCS8_bio, 324i2d_PKCS8_fp, 325i2d_PKEY_USAGE_PERIOD, 326i2d_POLICYINFO, 327i2d_POLICYQUALINFO, 328i2d_PROFESSION_INFO, 329i2d_PROXY_CERT_INFO_EXTENSION, 330i2d_PROXY_POLICY, 331i2d_RSA_OAEP_PARAMS, 332i2d_RSA_PSS_PARAMS, 333i2d_SCRYPT_PARAMS, 334i2d_SCT_LIST, 335i2d_SXNET, 336i2d_SXNETID, 337i2d_TS_ACCURACY, 338i2d_TS_MSG_IMPRINT, 339i2d_TS_MSG_IMPRINT_bio, 340i2d_TS_MSG_IMPRINT_fp, 341i2d_TS_REQ, 342i2d_TS_REQ_bio, 343i2d_TS_REQ_fp, 344i2d_TS_RESP, 345i2d_TS_RESP_bio, 346i2d_TS_RESP_fp, 347i2d_TS_STATUS_INFO, 348i2d_TS_TST_INFO, 349i2d_TS_TST_INFO_bio, 350i2d_TS_TST_INFO_fp, 351i2d_USERNOTICE, 352i2d_X509, 353i2d_X509_bio, 354i2d_X509_fp, 355i2d_X509_ACERT, 356i2d_X509_ACERT_bio, 357i2d_X509_ACERT_fp, 358i2d_X509_ALGOR, 359i2d_X509_ALGORS, 360i2d_X509_ATTRIBUTE, 361i2d_X509_CERT_AUX, 362i2d_X509_CINF, 363i2d_X509_CRL, 364i2d_X509_CRL_INFO, 365i2d_X509_CRL_bio, 366i2d_X509_CRL_fp, 367i2d_X509_EXTENSION, 368i2d_X509_EXTENSIONS, 369i2d_X509_NAME, 370i2d_X509_NAME_ENTRY, 371i2d_X509_PUBKEY, 372i2d_X509_PUBKEY_bio, 373i2d_X509_PUBKEY_fp, 374i2d_X509_REQ, 375i2d_X509_REQ_INFO, 376i2d_X509_REQ_bio, 377i2d_X509_REQ_fp, 378i2d_X509_REVOKED, 379i2d_X509_SIG, 380i2d_X509_VAL, 381- convert objects from/to ASN.1/DER representation 382 383=head1 SYNOPSIS 384 385=for openssl generic 386 387 TYPE *d2i_TYPE(TYPE **a, const unsigned char **ppin, long length); 388 TYPE *d2i_TYPE_bio(BIO *bp, TYPE **a); 389 TYPE *d2i_TYPE_fp(FILE *fp, TYPE **a); 390 391 int i2d_TYPE(const TYPE *a, unsigned char **ppout); 392 int i2d_TYPE(TYPE *a, unsigned char **ppout); 393 int i2d_TYPE_fp(FILE *fp, const TYPE *a); 394 int i2d_TYPE_fp(FILE *fp, TYPE *a); 395 int i2d_TYPE_bio(BIO *bp, const TYPE *a); 396 int i2d_TYPE_bio(BIO *bp, TYPE *a); 397 398=head1 DESCRIPTION 399 400In the description here, B<I<TYPE>> is used a placeholder 401for any of the OpenSSL datatypes, such as B<X509_CRL>. 402The function parameters I<ppin> and I<ppout> are generally 403either both named I<pp> in the headers, or I<in> and I<out>. 404 405These functions convert OpenSSL objects to and from their ASN.1/DER 406encoding. Unlike the C structures which can have pointers to sub-objects 407within, the DER is a serialized encoding, suitable for sending over the 408network, writing to a file, and so on. 409 410B<d2i_I<TYPE>>() attempts to decode I<len> bytes at I<*ppin>. If successful a 411pointer to the B<I<TYPE>> structure is returned and I<*ppin> is incremented to 412the byte following the parsed data. If I<a> is not NULL then a pointer 413to the returned structure is also written to I<*a>. If an error occurred 414then NULL is returned. The caller retains ownership of the 415returned object and needs to free it when it is no longer needed, e.g. 416using X509_free() for X509 objects or DSA_SIG_free() for DSA_SIG objects. 417 418On a successful return, if I<*a> is not NULL then it is assumed that I<*a> 419contains a valid B<I<TYPE>> structure and an attempt is made to reuse it. 420For B<I<TYPE>> structures where it matters it is possible to set up a library 421context on the decoded structure this way (see the B<EXAMPLES> section). 422However using the "reuse" capability for other purposes is B<strongly 423discouraged> (see B<BUGS> below, and the discussion in the B<RETURN VALUES> 424section). 425 426B<d2i_I<TYPE>_bio>() is similar to B<d2i_I<TYPE>>() except it attempts 427to parse data from BIO I<bp>. 428 429B<d2i_I<TYPE>_fp>() is similar to B<d2i_I<TYPE>>() except it attempts 430to parse data from FILE pointer I<fp>. 431 432B<i2d_I<TYPE>>() encodes the structure pointed to by I<a> into DER format. 433If I<ppout> is not NULL, it writes the DER encoded data to the buffer 434at I<*ppout>, and increments it to point after the data just written. 435If the return value is negative an error occurred, otherwise it 436returns the length of the encoded data. 437 438If I<*ppout> is NULL memory will be allocated for a buffer and the encoded 439data written to it. In this case I<*ppout> is not incremented and it points 440to the start of the data just written. 441 442B<i2d_I<TYPE>_bio>() is similar to B<i2d_I<TYPE>>() except it writes 443the encoding of the structure I<a> to BIO I<bp> and it 444returns 1 for success and 0 for failure. 445 446B<i2d_I<TYPE>_fp>() is similar to B<i2d_I<TYPE>>() except it writes 447the encoding of the structure I<a> to FILE pointer I<fp> and it 448returns 1 for success and 0 for failure. 449 450These routines do not encrypt private keys and therefore offer no 451security; use L<PEM_write_PrivateKey(3)> or similar for writing to files. 452 453=head1 NOTES 454 455The letters B<i> and B<d> in B<i2d_I<TYPE>>() stand for 456"internal" (that is, an internal C structure) and "DER" respectively. 457So B<i2d_I<TYPE>>() converts from internal to DER. 458 459The functions can also understand B<BER> forms. 460 461The actual TYPE structure passed to B<i2d_I<TYPE>>() must be a valid 462populated B<I<TYPE>> structure -- it B<cannot> simply be fed with an 463empty structure such as that returned by TYPE_new(). 464 465The encoded data is in binary form and may contain embedded zeros. 466Therefore, any FILE pointers or BIOs should be opened in binary mode. 467Functions such as strlen() will B<not> return the correct length 468of the encoded structure. 469 470The ways that I<*ppin> and I<*ppout> are incremented after the operation 471can trap the unwary. See the B<WARNINGS> section for some common 472errors. 473The reason for this-auto increment behaviour is to reflect a typical 474usage of ASN1 functions: after one structure is encoded or decoded 475another will be processed after it. 476 477The following points about the data types might be useful: 478 479=over 4 480 481=item B<ASN1_OBJECT> 482 483Represents an ASN1 OBJECT IDENTIFIER. 484 485=item B<DHparams> 486 487Represents a PKCS#3 DH parameters structure. 488 489=item B<DHxparams> 490 491Represents an ANSI X9.42 DH parameters structure. 492 493=item B<ECDSA_SIG> 494 495Represents an ECDSA signature. 496 497=item B<X509_ALGOR> 498 499Represents an B<AlgorithmIdentifier> structure as used in IETF RFC 6960 and 500elsewhere. 501 502=item B<X509_NAME> 503 504Represents a B<Name> type as used for subject and issuer names in 505IETF RFC 6960 and elsewhere. 506 507=item B<X509_REQ> 508 509Represents a PKCS#10 certificate request. 510 511=item B<X509_SIG> 512 513Represents the B<DigestInfo> structure defined in PKCS#1 and PKCS#7. 514 515=back 516 517=head1 RETURN VALUES 518 519B<d2i_I<TYPE>>(), B<d2i_I<TYPE>_bio>() and B<d2i_I<TYPE>_fp>() return a valid 520B<I<TYPE>> structure or NULL if an error occurs. If the "reuse" capability has 521been used with a valid structure being passed in via I<a>, then the object is 522freed in the event of error and I<*a> is set to NULL. 523 524B<i2d_I<TYPE>>() returns the number of bytes successfully encoded or a negative 525value if an error occurs. 526 527B<i2d_I<TYPE>_bio>() and B<i2d_I<TYPE>_fp>() return 1 for success and 0 if an 528error occurs. 529 530=head1 EXAMPLES 531 532Allocate and encode the DER encoding of an X509 structure: 533 534 int len; 535 unsigned char *buf; 536 537 buf = NULL; 538 len = i2d_X509(x, &buf); 539 if (len < 0) 540 /* error */ 541 542Attempt to decode a buffer: 543 544 X509 *x; 545 unsigned char *buf; 546 const unsigned char *p; 547 int len; 548 549 /* Set up buf and len to point to the input buffer. */ 550 p = buf; 551 x = d2i_X509(NULL, &p, len); 552 if (x == NULL) 553 /* error */ 554 555Alternative technique: 556 557 X509 *x; 558 unsigned char *buf; 559 const unsigned char *p; 560 int len; 561 562 /* Set up buf and len to point to the input buffer. */ 563 p = buf; 564 x = NULL; 565 566 if (d2i_X509(&x, &p, len) == NULL) 567 /* error */ 568 569Setting up a library context and property query: 570 571 X509 *x; 572 unsigned char *buf; 573 const unsigned char *p; 574 int len; 575 OSSL_LIB_CTX *libctx = ....; 576 const char *propq = ....; 577 578 /* Set up buf and len to point to the input buffer. */ 579 p = buf; 580 x = X509_new_ex(libctx, propq); 581 582 if (d2i_X509(&x, &p, len) == NULL) 583 /* error, x was freed and NULL assigned to it (see RETURN VALUES) */ 584 585=head1 WARNINGS 586 587Using a temporary variable is mandatory. A common 588mistake is to attempt to use a buffer directly as follows: 589 590 int len; 591 unsigned char *buf; 592 593 len = i2d_X509(x, NULL); 594 buf = OPENSSL_malloc(len); 595 ... 596 i2d_X509(x, &buf); 597 ... 598 OPENSSL_free(buf); 599 600This code will result in I<buf> apparently containing garbage because 601it was incremented after the call to point after the data just written. 602Also I<buf> will no longer contain the pointer allocated by OPENSSL_malloc() 603and the subsequent call to OPENSSL_free() is likely to crash. 604 605Another trap to avoid is misuse of the I<a> argument to B<d2i_I<TYPE>>(): 606 607 X509 *x; 608 609 if (d2i_X509(&x, &p, len) == NULL) 610 /* error */ 611 612This will probably crash somewhere in d2i_X509(). The reason for this 613is that the variable I<x> is uninitialized and an attempt will be made to 614interpret its (invalid) value as an B<X509> structure, typically causing 615a segmentation violation. If I<x> is set to NULL first then this will not 616happen. 617 618=head1 BUGS 619 620In some versions of OpenSSL the "reuse" behaviour of B<d2i_I<TYPE>>() when 621I<*a> is valid is broken and some parts of the reused structure may 622persist if they are not present in the new one. Additionally, in versions of 623OpenSSL prior to 1.1.0, when the "reuse" behaviour is used and an error occurs 624the behaviour is inconsistent. Some functions behaved as described here, while 625some did not free I<*a> on error and did not set I<*a> to NULL. 626 627As a result of the above issues the "reuse" behaviour is strongly discouraged. 628 629B<i2d_I<TYPE>>() will not return an error in many versions of OpenSSL, 630if mandatory fields are not initialized due to a programming error 631then the encoded structure may contain invalid data or omit the 632fields entirely and will not be parsed by B<d2i_I<TYPE>>(). This may be 633fixed in future so code should not assume that B<i2d_I<TYPE>>() will 634always succeed. 635 636Any function which encodes a structure (B<i2d_I<TYPE>>(), 637B<i2d_I<TYPE>_bio>() or B<i2d_I<TYPE>_fp>()) may return a stale encoding if the 638structure has been modified after deserialization or previous 639serialization. This is because some objects cache the encoding for 640efficiency reasons. 641 642=head1 COPYRIGHT 643 644Copyright 1998-2023 The OpenSSL Project Authors. All Rights Reserved. 645 646Licensed under the Apache License 2.0 (the "License"). You may not use 647this file except in compliance with the License. You can obtain a copy 648in the file LICENSE in the source distribution or at 649L<https://www.openssl.org/source/license.html>. 650 651=cut 652
