doc/man3/OSSL_CMP_CTX_new.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 OSSL_CMP_CTX_new,
   6 OSSL_CMP_CTX_free,
   7 OSSL_CMP_CTX_reinit,
   8 OSSL_CMP_CTX_set_option,
   9 OSSL_CMP_CTX_get_option,
  10 OSSL_CMP_CTX_set_log_cb,
  11 OSSL_CMP_CTX_set_log_verbosity,
  12 OSSL_CMP_CTX_print_errors,
  13 OSSL_CMP_CTX_set1_serverPath,
  14 OSSL_CMP_CTX_set1_server,
  15 OSSL_CMP_CTX_set_serverPort,
  16 OSSL_CMP_CTX_set1_proxy,
  17 OSSL_CMP_CTX_set1_no_proxy,
  18 OSSL_CMP_CTX_set_http_cb,
  19 OSSL_CMP_CTX_set_http_cb_arg,
  20 OSSL_CMP_CTX_get_http_cb_arg,
  21 OSSL_CMP_transfer_cb_t,
  22 OSSL_CMP_CTX_set_transfer_cb,
  23 OSSL_CMP_CTX_set_transfer_cb_arg,
  24 OSSL_CMP_CTX_get_transfer_cb_arg,
  25 OSSL_CMP_CTX_set1_srvCert,
  26 OSSL_CMP_CTX_set1_expected_sender,
  27 OSSL_CMP_CTX_set0_trustedStore,
  28 OSSL_CMP_CTX_get0_trustedStore,
  29 OSSL_CMP_CTX_set1_untrusted_certs,
  30 OSSL_CMP_CTX_get0_untrusted_certs,
  31 OSSL_CMP_CTX_set1_cert,
  32 OSSL_CMP_CTX_build_cert_chain,
  33 OSSL_CMP_CTX_set1_pkey,
  34 OSSL_CMP_CTX_set1_referenceValue,
  35 OSSL_CMP_CTX_set1_secretValue,
  36 OSSL_CMP_CTX_set1_recipient,
  37 OSSL_CMP_CTX_push0_geninfo_ITAV,
  38 OSSL_CMP_CTX_set1_extraCertsOut,
  39 OSSL_CMP_CTX_set0_newPkey,
  40 OSSL_CMP_CTX_get0_newPkey,
  41 OSSL_CMP_CTX_set1_issuer,
  42 OSSL_CMP_CTX_set1_subjectName,
  43 OSSL_CMP_CTX_push1_subjectAltName,
  44 OSSL_CMP_CTX_set0_reqExtensions,
  45 OSSL_CMP_CTX_reqExtensions_have_SAN,
  46 OSSL_CMP_CTX_push0_policy,
  47 OSSL_CMP_CTX_set1_oldCert,
  48 OSSL_CMP_CTX_set1_p10CSR,
  49 OSSL_CMP_CTX_push0_genm_ITAV,
  50 OSSL_CMP_certConf_cb_t,
  51 OSSL_CMP_CTX_set_certConf_cb,
  52 OSSL_CMP_CTX_set_certConf_cb_arg,
  53 OSSL_CMP_CTX_get_certConf_cb_arg,
  54 OSSL_CMP_CTX_get_status,
  55 OSSL_CMP_CTX_get0_statusString,
  56 OSSL_CMP_CTX_get_failInfoCode,
  57 OSSL_CMP_CTX_get0_newCert,
  58 OSSL_CMP_CTX_get1_newChain,
  59 OSSL_CMP_CTX_get1_caPubs,
  60 OSSL_CMP_CTX_get1_extraCertsIn,
  61 OSSL_CMP_CTX_set1_transactionID,
  62 OSSL_CMP_CTX_set1_senderNonce
  63 - functions for managing the CMP client context data structure
  64
  65 =head1 SYNOPSIS
  66
  67  #include <openssl/cmp.h>
  68
  69  OSSL_CMP_CTX *OSSL_CMP_CTX_new(OPENSSL_CTX *libctx, const char *propq);
  70  void OSSL_CMP_CTX_free(OSSL_CMP_CTX *ctx);
  71  int OSSL_CMP_CTX_reinit(OSSL_CMP_CTX *ctx);
  72  int OSSL_CMP_CTX_set_option(OSSL_CMP_CTX *ctx, int opt, int val);
  73  int OSSL_CMP_CTX_get_option(const OSSL_CMP_CTX *ctx, int opt);
  74
  75  /* logging and error reporting: */
  76  int OSSL_CMP_CTX_set_log_cb(OSSL_CMP_CTX *ctx, OSSL_CMP_log_cb_t cb);
  77  #define OSSL_CMP_CTX_set_log_verbosity(ctx, level)
  78  void OSSL_CMP_CTX_print_errors(const OSSL_CMP_CTX *ctx);
  79
  80  /* message transfer: */
  81  int OSSL_CMP_CTX_set1_serverPath(OSSL_CMP_CTX *ctx, const char *path);
  82  int OSSL_CMP_CTX_set1_server(OSSL_CMP_CTX *ctx, const char *address);
  83  int OSSL_CMP_CTX_set_serverPort(OSSL_CMP_CTX *ctx, int port);
  84  int OSSL_CMP_CTX_set1_proxy(OSSL_CMP_CTX *ctx, const char *name);
  85  int OSSL_CMP_CTX_set1_no_proxy(OSSL_CMP_CTX *ctx, const char *names);
  86  int OSSL_CMP_CTX_set_http_cb(OSSL_CMP_CTX *ctx, HTTP_bio_cb_t cb);
  87  int OSSL_CMP_CTX_set_http_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
  88  void *OSSL_CMP_CTX_get_http_cb_arg(const OSSL_CMP_CTX *ctx);
  89  typedef OSSL_CMP_MSG *(*OSSL_CMP_transfer_cb_t)(OSSL_CMP_CTX *ctx,
  90                                                  const OSSL_CMP_MSG *req);
  91  int OSSL_CMP_CTX_set_transfer_cb(OSSL_CMP_CTX *ctx,
  92                                   OSSL_CMP_transfer_cb_t cb);
  93  int OSSL_CMP_CTX_set_transfer_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
  94  void *OSSL_CMP_CTX_get_transfer_cb_arg(const OSSL_CMP_CTX *ctx);
  95
  96  /* server authentication: */
  97  int OSSL_CMP_CTX_set1_srvCert(OSSL_CMP_CTX *ctx, X509 *cert);
  98  int OSSL_CMP_CTX_set1_expected_sender(OSSL_CMP_CTX *ctx,
  99                                       const X509_NAME *name);
 100  int OSSL_CMP_CTX_set0_trustedStore(OSSL_CMP_CTX *ctx, X509_STORE *store);
 101  X509_STORE *OSSL_CMP_CTX_get0_trustedStore(const OSSL_CMP_CTX *ctx);
 102  int OSSL_CMP_CTX_set1_untrusted_certs(OSSL_CMP_CTX *ctx,
 103                                        STACK_OF(X509) *certs);
 104  STACK_OF(X509) *OSSL_CMP_CTX_get0_untrusted_certs(const OSSL_CMP_CTX *ctx);
 105
 106  /* client authentication: */
 107  int OSSL_CMP_CTX_set1_cert(OSSL_CMP_CTX *ctx, X509 *cert);
 108  int OSSL_CMP_CTX_build_cert_chain(OSSL_CMP_CTX *ctx, X509_STORE *own_trusted,
 109                                    STACK_OF(X509) *candidates);
 110  int OSSL_CMP_CTX_set1_pkey(OSSL_CMP_CTX *ctx, EVP_PKEY *pkey);
 111  int OSSL_CMP_CTX_set1_referenceValue(OSSL_CMP_CTX *ctx,
 112                                       const unsigned char *ref, int len);
 113  int OSSL_CMP_CTX_set1_secretValue(OSSL_CMP_CTX *ctx, const unsigned char *sec,
 114                                    const int len);
 115
 116  /* CMP message header and extra certificates: */
 117  int OSSL_CMP_CTX_set1_recipient(OSSL_CMP_CTX *ctx, const X509_NAME *name);
 118  int OSSL_CMP_CTX_push0_geninfo_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav);
 119  int OSSL_CMP_CTX_set1_extraCertsOut(OSSL_CMP_CTX *ctx,
 120                                      STACK_OF(X509) *extraCertsOut);
 121
 122  /* certificate template: */
 123  int OSSL_CMP_CTX_set0_newPkey(OSSL_CMP_CTX *ctx, int priv, EVP_PKEY *pkey);
 124  EVP_PKEY *OSSL_CMP_CTX_get0_newPkey(const OSSL_CMP_CTX *ctx, int priv);
 125  int OSSL_CMP_CTX_set1_issuer(OSSL_CMP_CTX *ctx, const X509_NAME *name);
 126  int OSSL_CMP_CTX_set1_subjectName(OSSL_CMP_CTX *ctx, const X509_NAME *name);
 127  int OSSL_CMP_CTX_push1_subjectAltName(OSSL_CMP_CTX *ctx,
 128                                        const GENERAL_NAME *name);
 129  int OSSL_CMP_CTX_set0_reqExtensions(OSSL_CMP_CTX *ctx, X509_EXTENSIONS *exts);
 130  int OSSL_CMP_CTX_reqExtensions_have_SAN(OSSL_CMP_CTX *ctx);
 131  int OSSL_CMP_CTX_push0_policy(OSSL_CMP_CTX *ctx, POLICYINFO *pinfo);
 132  int OSSL_CMP_CTX_set1_oldCert(OSSL_CMP_CTX *ctx, X509 *cert);
 133  int OSSL_CMP_CTX_set1_p10CSR(OSSL_CMP_CTX *ctx, const X509_REQ *csr);
 134
 135  /* misc body contents: */
 136  int OSSL_CMP_CTX_push0_genm_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav);
 137
 138  /* certificate confirmation: */
 139  typedef int (*OSSL_CMP_certConf_cb_t)(OSSL_CMP_CTX *ctx, X509 *cert,
 140                                        int fail_info, const char **txt);
 141  int OSSL_CMP_CTX_set_certConf_cb(OSSL_CMP_CTX *ctx, OSSL_CMP_certConf_cb_t cb);
 142  int OSSL_CMP_CTX_set_certConf_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
 143  void *OSSL_CMP_CTX_get_certConf_cb_arg(const OSSL_CMP_CTX *ctx);
 144
 145  /* result fetching: */
 146  int OSSL_CMP_CTX_get_status(const OSSL_CMP_CTX *ctx);
 147  OSSL_CMP_PKIFREETEXT *OSSL_CMP_CTX_get0_statusString(const OSSL_CMP_CTX *ctx);
 148  int OSSL_CMP_CTX_get_failInfoCode(const OSSL_CMP_CTX *ctx);
 149
 150  X509 *OSSL_CMP_CTX_get0_newCert(const OSSL_CMP_CTX *ctx);
 151  STACK_OF(X509) *OSSL_CMP_CTX_get1_newChain(const OSSL_CMP_CTX *ctx);
 152  STACK_OF(X509) *OSSL_CMP_CTX_get1_caPubs(const OSSL_CMP_CTX *ctx);
 153  STACK_OF(X509) *OSSL_CMP_CTX_get1_extraCertsIn(const OSSL_CMP_CTX *ctx);
 154
 155  /* for testing and debugging purposes: */
 156  int OSSL_CMP_CTX_set1_transactionID(OSSL_CMP_CTX *ctx,
 157                                      const ASN1_OCTET_STRING *id);
 158  int OSSL_CMP_CTX_set1_senderNonce(OSSL_CMP_CTX *ctx,
 159                                    const ASN1_OCTET_STRING *nonce);
 160
 161 =head1 DESCRIPTION
 162
 163 This is the context API for using CMP (Certificate Management Protocol) with
 164 OpenSSL.
 165
 166 OSSL_CMP_CTX_new() allocates an B<OSSL_CMP_CTX> structure associated with
 167 the library context I<libctx> and property query string I<propq>,
 168 both of which may be NULL to select the defaults.
 169 It initializes the remaining fields to their default values - for instance,
 170 the logging verbosity is set to OSSL_CMP_LOG_INFO,
 171 the message timeout is set to 120 seconds,
 172 and the proof-of-possession method is set to OSSL_CRMF_POPO_SIGNATURE.
 173
 174 OSSL_CMP_CTX_free() deallocates an OSSL_CMP_CTX structure.
 175
 176 OSSL_CMP_CTX_reinit() prepares the given B<ctx> for a further transaction by
 177 clearing the internal CMP transaction (aka session) status, PKIStatusInfo,
 178 and any previous results (newCert, newChain, caPubs, and extraCertsIn)
 179 from the last executed transaction.
 180 All other field values (i.e., CMP options) are retained for potential re-use.
 181
 182 OSSL_CMP_CTX_set_option() sets the given value for the given option
 183 (e.g., OSSL_CMP_OPT_IMPLICIT_CONFIRM) in the given OSSL_CMP_CTX structure.
 184
 185 The following options can be set:
 186
 187 =over 4
 188
 189 =item B<OSSL_CMP_OPT_LOG_VERBOSITY>
 190
 191         The level of severity needed for actually outputting log messages
 192         due to errors, warnings, general info, debugging, etc.
 193         Default is OSSL_CMP_LOG_INFO. See also L<OSSL_CMP_log_open(3)>.
 194
 195 =item B<OSSL_CMP_OPT_MSG_TIMEOUT>
 196
 197         Number of seconds (or 0 for infinite) a CMP message round trip is
 198         allowed to take before a timeout error is returned. Default is 120.
 199
 200 =item B<OSSL_CMP_OPT_TOTAL_TIMEOUT>
 201
 202         Maximum total number of seconds an enrollment (including polling)
 203         may take. Default is 0 (infinite).
 204
 205 =item B<OSSL_CMP_OPT_VALIDITY_DAYS>
 206
 207         Number of days new certificates are asked to be valid for.
 208
 209 =item B<OSSL_CMP_OPT_SUBJECTALTNAME_NODEFAULT>
 210
 211         Do not take default Subject Alternative Names
 212         from the reference certificate.
 213
 214 =item B<OSSL_CMP_OPT_SUBJECTALTNAME_CRITICAL>
 215
 216         Demand that the given Subject Alternative Names are flagged as critical.
 217
 218 =item B<OSSL_CMP_OPT_POLICIES_CRITICAL>
 219
 220         Demand that the given policies are flagged as critical.
 221
 222 =item B<OSSL_CMP_OPT_POPO_METHOD>
 223
 224         Select the proof of possession method to use. Possible values are:
 225
 226             OSSL_CRMF_POPO_NONE       - ProofOfPossession field omitted
 227             OSSL_CRMF_POPO_RAVERIFIED - assert that the RA has already
 228                                         verified the PoPo
 229             OSSL_CRMF_POPO_SIGNATURE  - sign a value with private key,
 230                                         which is the default.
 231             OSSL_CRMF_POPO_KEYENC     - decrypt the encrypted certificate
 232                                         ("indirect method")
 233
 234         Note that a signature-based POPO can only be produced if a private key
 235         is provided as the newPkey or client pkey component of the CMP context.
 236
 237 =item B<OSSL_CMP_OPT_DIGEST_ALGNID>
 238
 239         The NID of the digest algorithm to be used in RFC 4210's MSG_SIG_ALG
 240         for signature-based message protection and Proof-of-Possession (POPO).
 241         Default is SHA256.
 242
 243 =item B<OSSL_CMP_OPT_OWF_ALGNID>
 244         The NID of the digest algorithm to be used as one-way function (OWF)
 245         in RFC 4210's MSG_MAC_ALG for PBM-based message protection.
 246         Default is SHA256.
 247
 248 =item B<OSSL_CMP_OPT_MAC_ALGNID>
 249         The NID of the MAC algorithm to be used in RFC 4210's MSG_MAC_ALG
 250         for PBM-based message protection.
 251         Default is HMAC-SHA1 as per RFC 4210.
 252
 253 =item B<OSSL_CMP_OPT_REVOCATION_REASON>
 254
 255         The reason code to be included in a Revocation Request (RR);
 256         values: 0..10 (RFC 5210, 5.3.1) or -1 for none, which is the default.
 257
 258 =item B<OSSL_CMP_OPT_IMPLICIT_CONFIRM>
 259
 260         Request server to enable implicit confirm mode, where the client
 261         does not need to send confirmation upon receiving the
 262         certificate. If the server does not enable implicit confirmation
 263         in the return message, then confirmation is sent anyway.
 264
 265 =item B<OSSL_CMP_OPT_DISABLE_CONFIRM>
 266
 267         Do not confirm enrolled certificates, to cope with broken servers
 268         not supporting implicit confirmation correctly.
 269 B<WARNING:> This setting leads to unspecified behavior and it is meant
 270 exclusively to allow interoperability with server implementations violating
 271 RFC 4210.
 272
 273 =item B<OSSL_CMP_OPT_UNPROTECTED_SEND>
 274
 275         Send messages without CMP-level protection.
 276
 277 =item B<OSSL_CMP_OPT_UNPROTECTED_ERRORS>
 278
 279         Accept unprotected error responses which are either explicitly
 280         unprotected or where protection verification failed. Applies to regular
 281         error messages as well as certificate responses (IP/CP/KUP) and
 282         revocation responses (RP) with rejection.
 283 B<WARNING:> This setting leads to unspecified behavior and it is meant
 284 exclusively to allow interoperability with server implementations violating
 285 RFC 4210.
 286
 287 =item B<OSSL_CMP_OPT_IGNORE_KEYUSAGE>
 288
 289         Ignore key usage restrictions in signer certificate when
 290         validating signature-based protection in received CMP messages.
 291         Else, 'digitalSignature' must be allowed by CMP signer certificates.
 292
 293 =item B<OSSL_CMP_OPT_PERMIT_TA_IN_EXTRACERTS_FOR_IR>
 294
 295         Allow retrieving a trust anchor from extraCerts and using that
 296         to validate the certificate chain of an IP message.
 297
 298 =back
 299
 300 OSSL_CMP_CTX_get_option() reads the current value of the given option
 301 (e.g., OSSL_CMP_OPT_IMPLICIT_CONFIRM) from the given OSSL_CMP_CTX structure.
 302
 303 OSSL_CMP_CTX_set_log_cb() sets in B<ctx> the callback function C<cb>
 304 for handling error queue entries and logging messages.
 305 When C<cb> is NULL errors are printed to STDERR (if available, else ignored)
 306 any log messages are ignored.
 307 Alternatively, L<OSSL_CMP_log_open(3)> may be used to direct logging to STDOUT.
 308
 309 OSSL_CMP_CTX_set_log_verbosity() is a macro setting the
 310 OSSL_CMP_OPT_LOG_VERBOSITY context option to the given level.
 311
 312 OSSL_CMP_CTX_print_errors() outputs any entries in the OpenSSL error queue.
 313 It is similar to B<ERR_print_errors_cb()> but uses the CMP log callback function
 314 if set in the C<ctx> for uniformity with CMP logging if given. Otherwise it uses
 315 B<ERR_print_errors(3)> to print to STDERR (unless OPENSSL_NO_STDIO is defined).
 316
 317 OSSL_CMP_CTX_set1_serverPath() sets the HTTP path of the CMP server on the host,
 318 also known as "CMP alias".
 319 The default is I</>.
 320
 321 OSSL_CMP_CTX_set1_server() sets the given server B<address>
 322 (which may be a hostname or IP address or NULL) in the given B<ctx>.
 323
 324 OSSL_CMP_CTX_set_serverPort() sets the port of the CMP server to connect to.
 325 If not used or the B<port> argument is 0
 326 the default port applies, which is 80 for HTTP and 443 for HTTPS.
 327
 328 OSSL_CMP_CTX_set1_proxy() sets the HTTP proxy to be used for connecting to
 329 the given CMP server unless overruled by any "no_proxy" settings (see below).
 330 If TLS is not used this defaults to the value of
 331 the environment variable B<http_proxy> if set, else B<HTTP_PROXY>.
 332 Otherwise defaults to the value of B<https_proxy> if set, else B<HTTPS_PROXY>.
 333 An empty proxy string specifies not to use a proxy.
 334 Else the format is I<[http[s]://]address[:port][/path]>,
 335 where any path given is ignored.
 336 The default port number is 80, or 443 in case I<https:> is given.
 337
 338 OSSL_CMP_CTX_set1_no_proxy() sets the list of server hostnames not to use
 339 an HTTP proxy for. The names may be separated by commas and/or whitespace.
 340 Defaults to the environment variable B<no_proxy> if set, else B<NO_PROXY>.
 341
 342 OSSL_CMP_CTX_set_http_cb() sets the optional BIO connect/disconnect callback
 343 function, which has the prototype
 344
 345  typedef BIO *(*HTTP_bio_cb_t) (BIO *bio, void *ctx, int connect, int detail);
 346
 347 The callback may modify the BIO B<bio> provided by OSSL_CMP_MSG_http_perform(),
 348 whereby it may make use of a custom defined argument B<ctx>
 349 stored in the OSSL_CMP_CTX by means of OSSL_CMP_CTX_set_http_cb_arg().
 350 During connection establishment, just after calling BIO_do_connect_retry(),
 351 the function is invoked with the B<connect> argument being 1 and the B<detail>
 352 argument being 1 if HTTPS is requested, i.e., SSL/TLS should be enabled. On
 353 disconnect B<connect> is 0 and B<detail> is 1 in case no error occurred, else 0.
 354 For instance, on connect the function may prepend a TLS BIO to implement HTTPS;
 355 after disconnect it may do some diagnostic output and/or specific cleanup.
 356 The function should return NULL to indicate failure.
 357 After disconnect the modified BIO will be deallocated using BIO_free_all().
 358
 359 OSSL_CMP_CTX_set_http_cb_arg() sets an argument, respectively a pointer to
 360 a structure containing arguments,
 361 optionally to be used by the http connect/disconnect callback function.
 362 B<arg> is not consumed, and it must therefore explicitly be freed when not
 363 needed any more. B<arg> may be NULL to clear the entry.
 364
 365 OSSL_CMP_CTX_get_http_cb_arg() gets the argument, respectively the pointer to a
 366 structure containing arguments, previously set by
 367 OSSL_CMP_CTX_set_http_cb_arg() or NULL if unset.
 368
 369 OSSL_CMP_CTX_set_transfer_cb() sets the message transfer callback function,
 370 which has the type
 371
 372  typedef OSSL_CMP_MSG *(*OSSL_CMP_transfer_cb_t) (OSSL_CMP_CTX *ctx,
 373                                                   const OSSL_CMP_MSG *req);
 374
 375 Returns 1 on success, 0 on error.
 376
 377 Default is NULL, which implies the use of L<OSSL_CMP_MSG_http_perform(3)>.
 378 The callback should send the CMP request message it obtains via the B<req>
 379 parameter and on success return the response, else it must return NULL.
 380 The transfer callback may make use of a custom defined argument stored in
 381 the ctx by means of OSSL_CMP_CTX_set_transfer_cb_arg(), which may be retrieved
 382 again through OSSL_CMP_CTX_get_transfer_cb_arg().
 383
 384 OSSL_CMP_CTX_set_transfer_cb_arg() sets an argument, respectively a pointer to a
 385 structure containing arguments, optionally to be used by the transfer callback.
 386 B<arg> is not consumed, and it must therefore explicitly be freed when not
 387 needed any more. B<arg> may be NULL to clear the entry.
 388
 389 OSSL_CMP_CTX_get_transfer_cb_arg() gets the argument, respectively the pointer
 390 to a structure containing arguments, previously set by
 391 OSSL_CMP_CTX_set_transfer_cb_arg() or NULL if unset.
 392
 393 OSSL_CMP_CTX_set1_srvCert() sets the expected server cert B<srvCert> and trusts
 394 it directly (even if it is expired) when verifying signed response messages.
 395 May be used alternatively to OSSL_CMP_CTX_set0_trustedStore()
 396 to pin the accepted server.
 397 Any previously set value is freed.
 398 The B<cert> argument may be NULL to clear the entry.
 399 If set, the subject of the certificate is also used
 400 as default value for the recipient of CMP requests
 401 and as default value for the expected sender of CMP responses.
 402
 403 OSSL_CMP_CTX_set1_expected_sender() sets the Distinguished Name (DN)
 404 expected in the sender field of CMP response messages.
 405 Defaults to the subject of the pinned server certificate B<-srvcert>, if any.
 406 This can be used to make sure that only a particular entity is accepted as
 407 CMP message signer, and attackers are not able to use arbitrary certificates
 408 of a trusted PKI hierarchy to fraudulently pose as CMP server.
 409 Note that this gives slightly more freedom than OSSL_CMP_CTX_set1_srvCert(),
 410 which pins the server to the holder of a particular certificate, while the
 411 expected sender name will continue to match after updates of the server cert.
 412
 413 OSSL_CMP_CTX_set0_trustedStore() sets the certificate store of type X509_STORE
 414 containing trusted (root) CA certificates.
 415 The store may also hold CRLs and
 416 a certificate verification callback function used for CMP server authentication.
 417 Any store entry already set before is freed.
 418 When given a NULL parameter the entry is cleared.
 419
 420 OSSL_CMP_CTX_get0_trustedStore() returns a pointer to the currently set
 421 certificate store containing trusted cert etc., or an empty store if unset.
 422
 423 OSSL_CMP_CTX_set1_untrusted_certs() sets up a list of non-trusted certificates
 424 of intermediate CAs that may be useful for path construction for the CMP client
 425 certificate, for the TLS client certificate (if any), when verifying
 426 the CMP server certificate, and when verifying newly enrolled certificates.
 427 The reference counts of those certificates handled successfully are increased.
 428
 429 OSSL_CMP_CTX_get0_untrusted_certs(OSSL_CMP_CTX *ctx) returns a pointer to the
 430 list of untrusted certs, which may be empty if unset.
 431
 432 OSSL_CMP_CTX_set1_cert() sets the certificate used for CMP message protection.
 433 The public key of this B<cert> must correspond to
 434 the private key set via B<OSSL_CMP_CTX_set1_pkey()>.
 435 When using signature-based protection of CMP request messages
 436 this "protection certificate" will be included first in the extraCerts field.
 437 The subject of this B<cert> will be used as the sender field of outgoing
 438 messages, while the subject of any cert set via B<OSSL_CMP_CTX_set1_oldCert()>
 439 and any value set via B<OSSL_CMP_CTX_set1_subjectName()> are used as fallback.
 440 The B<cert> argument may be NULL to clear the entry.
 441
 442 OSSL_CMP_CTX_build_cert_chain() builds a certificate chain for the CMP signer
 443 certificate previously set in the B<ctx>. It adds the optional B<candidates>,
 444 a list of intermediate CA certs that may already constitute the targeted chain,
 445 to the untrusted certs that may already exist in the B<ctx>.
 446 Then the function uses this augumented set of certs for chain construction.
 447 If I<own_trusted> is NULL it builds the chain as far down as possible and
 448 ignores any verification errors. Else the CMP signer certificate must be
 449 verifiable where the chain reaches a trust anchor contained in I<own_trusted>.
 450 On success the function stores the resulting chain in B<ctx>
 451 for inclusion in the extraCerts field of signature-protected messages.
 452 Calling this function is optional; by default a chain construction
 453 is performed on demand that is equivalent to calling this function
 454 with the B<candidates> and I<own_trusted> arguments being NULL.
 455
 456 OSSL_CMP_CTX_set1_pkey() sets the private key corresponding to the
 457 protection certificate B<cert> set via B<OSSL_CMP_CTX_set1_cert()>.
 458 This key is used create signature-based protection (protectionAlg = MSG_SIG_ALG)
 459 of outgoing messages
 460 unless a PBM secret has been set via  B<OSSL_CMP_CTX_set1_secretValue()>.
 461 The B<pkey> argument may be NULL to clear the entry.
 462
 463 OSSL_CMP_CTX_set1_secretValue() sets the byte string B<sec> with length B<len>
 464 as PBM secret in the given B<ctx> or clears it if the B<sec> argument is NULL.
 465 If present, this secret is used to create PBM-based protection of outgoing
 466 messages and to verify any PBM-based protection of incoming messages
 467 (protectionAlg = MSG_MAC_ALG). PBM stands for Password-Based MAC.
 468 PBM-based protection takes precedence over signature-based protection.
 469
 470 OSSL_CMP_CTX_set1_referenceValue() sets the given referenceValue B<ref> with
 471 length B<len> in the given B<ctx> or clears it if the B<ref> argument is NULL.
 472 According to RFC 4210 section 5.1.1, if no value for the sender field in
 473 CMP message headers can be determined (i.e., no protection certificate B<cert>
 474 and no B<subjectName> is given) then the sender field will contain the NULL-DN
 475 and the senderKID field of the CMP message header must be set.
 476 When signature-based protection is used the senderKID will be set to
 477 the subjectKeyIdentifier of the protection B<cert> as far as present.
 478 If not present or when PBM-based protection is used
 479 the B<ref> value is taken as the fallback value for the senderKID.
 480
 481 OSSL_CMP_CTX_set1_recipient() sets the recipient name that will be used in the
 482 PKIHeader of CMP request messages, i.e. the X509 name of the (CA) server.
 483
 484 The recipient field in the header of a CMP message is mandatory.
 485 If not given explicitly the recipient is determined in the following order:
 486 the subject of the CMP server certificate set using OSSL_CMP_CTX_set1_srvCert(),
 487 the value set using OSSL_CMP_CTX_set1_issuer(),
 488 the issuer of the certificate set using OSSL_CMP_CTX_set1_oldCert(),
 489 the issuer of the protection certificate (B<cert>),
 490 as far as any of those is present, else the NULL-DN as last resort.
 491
 492 OSSL_CMP_CTX_push0_geninfo_ITAV() adds B<itav> to the stack in the B<ctx> to be
 493 added to the GeneralInfo field of the CMP PKIMessage header of a request
 494 message sent with this context.
 495
 496 OSSL_CMP_CTX_set1_extraCertsOut() sets the stack of extraCerts that will be
 497 sent to remote.
 498
 499 OSSL_CMP_CTX_set0_newPkey() can be used to explicitly set the given EVP_PKEY
 500 structure as the private or public key to be certified in the CMP context.
 501 The B<priv> parameter must be 0 if and only if the given key is a public key.
 502
 503 OSSL_CMP_CTX_get0_newPkey() gives the key to use for certificate enrollment
 504 dependent on fields of the CMP context structure:
 505 the newPkey (which may be a private or public key) if present,
 506 else the public key in the p10CSR if present, else the client private key.
 507 If the B<priv> parameter is not 0 and the selected key does not have a
 508 private component then NULL is returned.
 509
 510 OSSL_CMP_CTX_set1_issuer() sets the name of the intended issuer that
 511 will be set in the CertTemplate, i.e., the X509 name of the CA server.
 512
 513 OSSL_CMP_CTX_set1_subjectName() sets the subject DN that will be used in
 514 the CertTemplate structure when requesting a new cert. For Key Update Requests
 515 (KUR), it defaults to the subject DN of the B<reference certificate>,
 516 see B<OSSL_CMP_CTX_set1_oldCert()>. This default is used for Initialization
 517 Requests (IR) and Certification Requests (CR) only if no SANs are set.
 518 The B<subjectName> is also used as fallback for the sender field
 519 of outgoing CMP messages if no B<cert> and no B<oldcert> are available.
 520
 521 OSSL_CMP_CTX_push1_subjectAltName() adds the given X509 name to the list of
 522 alternate names on the certificate template request. This cannot be used if
 523 any Subject Alternative Name extension is set via
 524 OSSL_CMP_CTX_set0_reqExtensions().
 525 By default, unless OSSL_CMP_OPT_SUBJECTALTNAME_NODEFAULT has been set,
 526 the Subject Alternative Names are copied from the B<reference certificate>,
 527 see B<OSSL_CMP_CTX_set1_oldCert()>.
 528 If set and the subject DN is not set with OSSL_CMP_CTX_set1_subjectName(), then
 529 the certificate template of an IR and CR will not be filled with the default
 530 subject DN from the B<reference certificate>.
 531 If a subject DN is desired it needs to be set explicitly with
 532 OSSL_CMP_CTX_set1_subjectName().
 533
 534 OSSL_CMP_CTX_set0_reqExtensions() sets the X.509v3 extensions to be used in
 535 IR/CR/KUR.
 536
 537 OSSL_CMP_CTX_reqExtensions_have_SAN() returns 1 if the context contains
 538 a Subject Alternative Name extension, else 0 or -1 on error.
 539
 540 OSSL_CMP_CTX_push0_policy() adds the certificate policy info object
 541 to the X509_EXTENSIONS of the requested certificate template.
 542
 543 OSSL_CMP_CTX_set1_oldCert() sets the old certificate to be updated in
 544 Key Update Requests (KUR) or to be revoked in Revocation Requests (RR).
 545 It must be given for RR, else it defaults to the protection B<cert>.
 546 The B<reference certificate> determined in this way, if any, is also used for
 547 deriving default subject DN and Subject Alternative Names for IR, CR, and KUR.
 548 Its subject is used as sender in CMP message headers if no protection cert is given.
 549 Its issuer is used as default recipient in CMP message headers.
 550
 551 OSSL_CMP_CTX_set1_p10CSR() sets the PKCS#10 CSR to be used in P10CR.
 552
 553 OSSL_CMP_CTX_push0_genm_ITAV() adds B<itav> to the stack in the B<ctx> which
 554 will be the body of a General Message sent with this context.
 555
 556 OSSL_CMP_CTX_set_certConf_cb() sets the callback used for evaluating the newly
 557 enrolled certificate before the library sends, depending on its result,
 558 a positive or negative certConf message to the server. The callback has type
 559
 560  typedef int (*OSSL_CMP_certConf_cb_t) (OSSL_CMP_CTX *ctx, X509 *cert,
 561                                         int fail_info, const char **txt);
 562
 563 and should inspect the certificate it obtains via the B<cert> parameter and may
 564 overrule the pre-decision given in the B<fail_info> and B<*txt> parameters.
 565 If it accepts the certificate it must return 0, indicating success. Else it must
 566 return a bit field reflecting PKIFailureInfo with at least one failure bit and
 567 may set the B<*txt> output parameter to point to a string constant with more
 568 detail.  The transfer callback may make use of a custom defined argument stored
 569 in the B<ctx> by means of OSSL_CMP_CTX_set_certConf_cb_arg(), which may be
 570 retrieved again through OSSL_CMP_CTX_get_certConf_cb_arg().
 571 Typically, the callback will check at least that the certificate can be verified
 572 using a set of trusted certificates.
 573 It also could compare the subject DN and other fields of the newly
 574 enrolled certificate with the certificate template of the request.
 575
 576 OSSL_CMP_CTX_set_certConf_cb_arg() sets an argument, respectively a pointer to a
 577 structure containing arguments, optionally to be used by the certConf callback.
 578 B<arg> is not consumed, and it must therefore explicitly be freed when not
 579 needed any more. B<arg> may be NULL to clear the entry.
 580
 581 OSSL_CMP_CTX_get_certConf_cb_arg() gets the argument, respectively the pointer
 582 to a structure containing arguments, previously set by
 583 OSSL_CMP_CTX_set_certConf_cb_arg(), or NULL if unset.
 584
 585 OSSL_CMP_CTX_get_status() returns the PKIstatus from the last received
 586 CertRepMessage or Revocation Response or error message, or -1 if unset.
 587
 588 OSSL_CMP_CTX_get0_statusString() returns the statusString from the last received
 589 CertRepMessage or Revocation Response or error message, or NULL if unset.
 590
 591 OSSL_CMP_CTX_get_failInfoCode() returns the error code from the failInfo field
 592 of the last received CertRepMessage or Revocation Response or error message.
 593 This is a bit field and the flags for it are specified in the header file
 594 F<< <openssl/cmp.h> >>.
 595 The flags start with OSSL_CMP_CTX_FAILINFO, for example:
 596 OSSL_CMP_CTX_FAILINFO_badAlg. Returns -1 if the failInfoCode field is unset.
 597
 598 OSSL_CMP_CTX_get0_newCert() returns the pointer to the newly obtained
 599 certificate in case it is available, else NULL.
 600
 601 OSSL_CMP_CTX_get1_newChain() returns a pointer to a duplicate of the stack of
 602 X.509 certificates computed by OSSL_CMP_certConf_cb() (if this function has
 603 been called) on the last received certificate response message IP/CP/KUP.
 604
 605 OSSL_CMP_CTX_get1_caPubs() returns a pointer to a duplicate of the stack of
 606 X.509 certificates received in the caPubs field of last received certificate
 607 response message IP/CP/KUP.
 608
 609 OSSL_CMP_CTX_get1_extraCertsIn() returns a pointer to a duplicate of the stack
 610 of X.509 certificates received in the last received nonempty extraCerts field.
 611 Returns an empty stack if no extraCerts have been received in the current
 612 transaction.
 613
 614 OSSL_CMP_CTX_set1_transactionID() sets the given transaction ID in the given
 615 OSSL_CMP_CTX structure.
 616
 617 OSSL_CMP_CTX_set1_senderNonce() stores the last sent sender B<nonce> in
 618 the B<ctx>. This will be used to validate the recipNonce in incoming messages.
 619
 620 =head1 NOTES
 621
 622 CMP is defined in RFC 4210 (and CRMF in RFC 4211).
 623
 624 =head1 RETURN VALUES
 625
 626 OSSL_CMP_CTX_free() and OSSL_CMP_CTX_print_errors() do not return anything.
 627
 628 OSSL_CMP_CTX_new(),
 629 OSSL_CMP_CTX_get_http_cb_arg(),
 630 OSSL_CMP_CTX_get_transfer_cb_arg(),
 631 OSSL_CMP_CTX_get0_trustedStore(),
 632 OSSL_CMP_CTX_get0_untrusted_certs(),
 633 OSSL_CMP_CTX_get0_newPkey(),
 634 OSSL_CMP_CTX_get_certConf_cb_arg(),
 635 OSSL_CMP_CTX_get0_statusString(),
 636 OSSL_CMP_CTX_get0_newCert(),
 637 OSSL_CMP_CTX_get0_newChain(),
 638 OSSL_CMP_CTX_get1_caPubs(), and
 639 OSSL_CMP_CTX_get1_extraCertsIn()
 640 return the intended pointer value as described above or NULL on error.
 641
 642 OSSL_CMP_CTX_get_option(),
 643 OSSL_CMP_CTX_reqExtensions_have_SAN(),
 644 OSSL_CMP_CTX_get_status(), and
 645 OSSL_CMP_CTX_get_failInfoCode()
 646 return the intended value as described above or -1 on error.
 647
 648 All other functions return 1 on success, 0 on error.
 649
 650 =head1 EXAMPLES
 651
 652 The following code omits error handling.
 653
 654 Set up a CMP client context for sending requests and verifying responses:
 655
 656     cmp_ctx = OSSL_CMP_CTX_new();
 657     OSSL_CMP_CTX_set1_server(cmp_ctx, name_or_address);
 658     OSSL_CMP_CTX_set1_serverPort(cmp_ctx, port_string);
 659     OSSL_CMP_CTX_set1_serverPath(cmp_ctx, path_or_alias);
 660     OSSL_CMP_CTX_set0_trustedStore(cmp_ctx, ts);
 661
 662 Set up client credentials for password-based protection (PBM):
 663
 664     OSSL_CMP_CTX_set1_referenceValue(cmp_ctx, ref, ref_len);
 665     OSSL_CMP_CTX_set1_secretValue(cmp_ctx, sec, sec_len);
 666
 667 Set up the details for certificate requests:
 668
 669     OSSL_CMP_CTX_set1_subjectName(cmp_ctx, name);
 670     OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, initialKey);
 671
 672 Perform an Initialization Request transaction:
 673
 674     initialCert = OSSL_CMP_exec_IR_ses(cmp_ctx);
 675
 676 Reset the transaction state of the CMP context and the credentials:
 677
 678     OSSL_CMP_CTX_reinit(cmp_ctx);
 679     OSSL_CMP_CTX_set1_referenceValue(cmp_ctx, NULL, 0);
 680     OSSL_CMP_CTX_set1_secretValue(cmp_ctx, NULL, 0);
 681
 682 Perform a Certification Request transaction, making use of the new credentials:
 683
 684     OSSL_CMP_CTX_set1_cert(cmp_ctx, initialCert);
 685     OSSL_CMP_CTX_set1_pkey(cmp_ctx, initialKey);
 686     OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, curentKey);
 687     currentCert = OSSL_CMP_exec_CR_ses(cmp_ctx);
 688
 689 Perform a Key Update Request, signed using the cert (and key) to be updated:
 690
 691     OSSL_CMP_CTX_reinit(cmp_ctx);
 692     OSSL_CMP_CTX_set1_cert(cmp_ctx, currentCert);
 693     OSSL_CMP_CTX_set1_pkey(cmp_ctx, currentKey);
 694     OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, updatedKey);
 695     currentCert = OSSL_CMP_exec_KUR_ses(cmp_ctx);
 696     currentKey = updatedKey;
 697
 698 Perform a General Message transaction including, as an example,
 699 the id-it-signKeyPairTypes OID and prints info on the General Response contents:
 700
 701     OSSL_CMP_CTX_reinit(cmp_ctx);
 702
 703     ASN1_OBJECT *type = OBJ_txt2obj("1.3.6.1.5.5.7.4.2", 1);
 704     OSSL_CMP_ITAV *itav = OSSL_CMP_ITAV_new(type, NULL);
 705     OSSL_CMP_CTX_push0_genm_ITAV(cmp_ctx, itav);
 706
 707     STACK_OF(OSSL_CMP_ITAV) *itavs;
 708     itavs = OSSL_CMP_exec_GENM_ses(cmp_ctx);
 709     print_itavs(itavs);
 710     sk_OSSL_CMP_ITAV_pop_free(itavs, OSSL_CMP_ITAV_free);
 711
 712 =head1 SEE ALSO
 713
 714 L<OSSL_CMP_exec_IR_ses(3)>, L<OSSL_CMP_exec_CR_ses(3)>,
 715 L<OSSL_CMP_exec_KUR_ses(3)>, L<OSSL_CMP_exec_GENM_ses(3)>,
 716 L<OSSL_CMP_exec_certreq(3)>
 717
 718 =head1 HISTORY
 719
 720 The OpenSSL CMP support was added in OpenSSL 3.0.
 721
 722 =head1 COPYRIGHT
 723
 724 Copyright 2007-2020 The OpenSSL Project Authors. All Rights Reserved.
 725
 726 Licensed under the Apache License 2.0 (the "License").  You may not use
 727 this file except in compliance with the License.  You can obtain a copy
 728 in the file LICENSE in the source distribution or at
 729 L<https://www.openssl.org/source/license.html>.
 730
 731 =cut