crypto/cmp/cmp_server.c

   1 /*
   2  * Copyright 2007-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright Nokia 2007-2019
   4  * Copyright Siemens AG 2015-2019
   5  *
   6  * Licensed under the Apache License 2.0 (the "License").  You may not use
   7  * this file except in compliance with the License.  You can obtain a copy
   8  * in the file LICENSE in the source distribution or at
   9  * https://www.openssl.org/source/license.html
  10  */
  11
  12 /* general CMP server functions */
  13
  14 #include <openssl/asn1t.h>
  15
  16 #include "cmp_local.h"
  17
  18 /* explicit #includes not strictly needed since implied by the above: */
  19 #include <openssl/cmp.h>
  20 #include <openssl/err.h>
  21
  22 DEFINE_STACK_OF(OSSL_CRMF_MSG)
  23 DEFINE_STACK_OF(OSSL_CMP_ITAV)
  24 DEFINE_STACK_OF(OSSL_CMP_CERTSTATUS)
  25
  26 /* the context for the generic CMP server */
  27 struct ossl_cmp_srv_ctx_st
  28 {
  29     OSSL_CMP_CTX *ctx; /* Client CMP context, partly reused for srv */
  30     void *custom_ctx;  /* pointer to specific server context */
  31
  32     OSSL_CMP_SRV_cert_request_cb_t process_cert_request;
  33     OSSL_CMP_SRV_rr_cb_t process_rr;
  34     OSSL_CMP_SRV_genm_cb_t process_genm;
  35     OSSL_CMP_SRV_error_cb_t process_error;
  36     OSSL_CMP_SRV_certConf_cb_t process_certConf;
  37     OSSL_CMP_SRV_pollReq_cb_t process_pollReq;
  38
  39     int sendUnprotectedErrors; /* Send error and rejection msgs unprotected */
  40     int acceptUnprotected;     /* Accept requests with no/invalid prot. */
  41     int acceptRAVerified;      /* Accept ir/cr/kur with POPO RAVerified */
  42     int grantImplicitConfirm;  /* Grant implicit confirmation if requested */
  43
  44 }; /* OSSL_CMP_SRV_CTX */
  45
  46 void OSSL_CMP_SRV_CTX_free(OSSL_CMP_SRV_CTX *srv_ctx)
  47 {
  48     if (srv_ctx == NULL)
  49         return;
  50
  51     OSSL_CMP_CTX_free(srv_ctx->ctx);
  52     OPENSSL_free(srv_ctx);
  53 }
  54
  55 OSSL_CMP_SRV_CTX *OSSL_CMP_SRV_CTX_new(OPENSSL_CTX *libctx, const char *propq)
  56 {
  57     OSSL_CMP_SRV_CTX *ctx = OPENSSL_zalloc(sizeof(OSSL_CMP_SRV_CTX));
  58
  59     if (ctx == NULL)
  60         goto err;
  61
  62     if ((ctx->ctx = OSSL_CMP_CTX_new(libctx, propq)) == NULL)
  63         goto err;
  64
  65     /* all other elements are initialized to 0 or NULL, respectively */
  66     return ctx;
  67  err:
  68     OSSL_CMP_SRV_CTX_free(ctx);
  69     return NULL;
  70 }
  71
  72 int OSSL_CMP_SRV_CTX_init(OSSL_CMP_SRV_CTX *srv_ctx, void *custom_ctx,
  73                           OSSL_CMP_SRV_cert_request_cb_t process_cert_request,
  74                           OSSL_CMP_SRV_rr_cb_t process_rr,
  75                           OSSL_CMP_SRV_genm_cb_t process_genm,
  76                           OSSL_CMP_SRV_error_cb_t process_error,
  77                           OSSL_CMP_SRV_certConf_cb_t process_certConf,
  78                           OSSL_CMP_SRV_pollReq_cb_t process_pollReq)
  79 {
  80     if (srv_ctx == NULL) {
  81         CMPerr(0, CMP_R_NULL_ARGUMENT);
  82         return 0;
  83     }
  84     srv_ctx->custom_ctx = custom_ctx;
  85     srv_ctx->process_cert_request = process_cert_request;
  86     srv_ctx->process_rr = process_rr;
  87     srv_ctx->process_genm = process_genm;
  88     srv_ctx->process_error = process_error;
  89     srv_ctx->process_certConf = process_certConf;
  90     srv_ctx->process_pollReq = process_pollReq;
  91     return 1;
  92 }
  93
  94 OSSL_CMP_CTX *OSSL_CMP_SRV_CTX_get0_cmp_ctx(const OSSL_CMP_SRV_CTX *srv_ctx)
  95 {
  96     if (srv_ctx == NULL) {
  97         CMPerr(0, CMP_R_NULL_ARGUMENT);
  98         return NULL;
  99     }
 100     return srv_ctx->ctx;
 101 }
 102
 103 void *OSSL_CMP_SRV_CTX_get0_custom_ctx(const OSSL_CMP_SRV_CTX *srv_ctx)
 104 {
 105     if (srv_ctx == NULL) {
 106         CMPerr(0, CMP_R_NULL_ARGUMENT);
 107         return NULL;
 108     }
 109     return srv_ctx->custom_ctx;
 110 }
 111
 112 int OSSL_CMP_SRV_CTX_set_send_unprotected_errors(OSSL_CMP_SRV_CTX *srv_ctx,
 113                                                  int val)
 114 {
 115     if (srv_ctx == NULL) {
 116         CMPerr(0, CMP_R_NULL_ARGUMENT);
 117         return 0;
 118     }
 119     srv_ctx->sendUnprotectedErrors = val != 0;
 120     return 1;
 121 }
 122
 123 int OSSL_CMP_SRV_CTX_set_accept_unprotected(OSSL_CMP_SRV_CTX *srv_ctx, int val)
 124 {
 125     if (srv_ctx == NULL) {
 126         CMPerr(0, CMP_R_NULL_ARGUMENT);
 127         return 0;
 128     }
 129     srv_ctx->acceptUnprotected = val != 0;
 130     return 1;
 131 }
 132
 133 int OSSL_CMP_SRV_CTX_set_accept_raverified(OSSL_CMP_SRV_CTX *srv_ctx, int val)
 134 {
 135     if (srv_ctx == NULL) {
 136         CMPerr(0, CMP_R_NULL_ARGUMENT);
 137         return 0;
 138     }
 139     srv_ctx->acceptRAVerified = val != 0;
 140     return 1;
 141 }
 142
 143 int OSSL_CMP_SRV_CTX_set_grant_implicit_confirm(OSSL_CMP_SRV_CTX *srv_ctx,
 144                                                 int val)
 145 {
 146     if (srv_ctx == NULL) {
 147         CMPerr(0, CMP_R_NULL_ARGUMENT);
 148         return 0;
 149     }
 150     srv_ctx->grantImplicitConfirm = val != 0;
 151     return 1;
 152 }
 153
 154 /*
 155  * Processes an ir/cr/p10cr/kur and returns a certification response.
 156  * Only handles the first certification request contained in req
 157  * returns an ip/cp/kup on success and NULL on error
 158  */
 159 static OSSL_CMP_MSG *process_cert_request(OSSL_CMP_SRV_CTX *srv_ctx,
 160                                           const OSSL_CMP_MSG *req)
 161 {
 162     OSSL_CMP_MSG *msg = NULL;
 163     OSSL_CMP_PKISI *si = NULL;
 164     X509 *certOut = NULL;
 165     STACK_OF(X509) *chainOut = NULL, *caPubs = NULL;
 166     const OSSL_CRMF_MSG *crm = NULL;
 167     const X509_REQ *p10cr = NULL;
 168     int bodytype;
 169     int certReqId;
 170
 171     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
 172         return NULL;
 173
 174     switch (ossl_cmp_msg_get_bodytype(req)) {
 175     case OSSL_CMP_PKIBODY_P10CR:
 176     case OSSL_CMP_PKIBODY_CR:
 177         bodytype = OSSL_CMP_PKIBODY_CP;
 178         break;
 179     case OSSL_CMP_PKIBODY_IR:
 180         bodytype = OSSL_CMP_PKIBODY_IP;
 181         break;
 182     case OSSL_CMP_PKIBODY_KUR:
 183         bodytype = OSSL_CMP_PKIBODY_KUP;
 184         break;
 185     default:
 186         CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 187         return NULL;
 188     }
 189
 190     if (ossl_cmp_msg_get_bodytype(req) == OSSL_CMP_PKIBODY_P10CR) {
 191         certReqId = OSSL_CMP_CERTREQID;
 192         p10cr = req->body->value.p10cr;
 193     } else {
 194         OSSL_CRMF_MSGS *reqs = req->body->value.ir; /* same for cr and kur */
 195
 196         if (sk_OSSL_CRMF_MSG_num(reqs) != 1) { /* TODO: handle case > 1 */
 197             CMPerr(0, CMP_R_MULTIPLE_REQUESTS_NOT_SUPPORTED);
 198             return NULL;
 199         }
 200
 201         if ((crm = sk_OSSL_CRMF_MSG_value(reqs, OSSL_CMP_CERTREQID)) == NULL) {
 202             CMPerr(0, CMP_R_CERTREQMSG_NOT_FOUND);
 203             return NULL;
 204         }
 205         certReqId = OSSL_CRMF_MSG_get_certReqId(crm);
 206     }
 207
 208     if (!ossl_cmp_verify_popo(srv_ctx->ctx, req, srv_ctx->acceptRAVerified)) {
 209         /* Proof of possession could not be verified */
 210         si = OSSL_CMP_STATUSINFO_new(OSSL_CMP_PKISTATUS_rejection,
 211                                      1 << OSSL_CMP_PKIFAILUREINFO_badPOP,
 212                                      ERR_reason_error_string(ERR_peek_error()));
 213         if (si == NULL)
 214             return NULL;
 215     } else {
 216         OSSL_CMP_PKIHEADER *hdr = OSSL_CMP_MSG_get0_header(req);
 217
 218         si = srv_ctx->process_cert_request(srv_ctx, req, certReqId, crm, p10cr,
 219                                            &certOut, &chainOut, &caPubs);
 220         if (si == NULL)
 221             goto err;
 222         /* set OSSL_CMP_OPT_IMPLICIT_CONFIRM if and only if transaction ends */
 223         if (!OSSL_CMP_CTX_set_option(srv_ctx->ctx,
 224                                      OSSL_CMP_OPT_IMPLICIT_CONFIRM,
 225                                      ossl_cmp_hdr_has_implicitConfirm(hdr)
 226                                          && srv_ctx->grantImplicitConfirm
 227                                          /* do not set if polling starts: */
 228                                          && certOut != NULL))
 229             goto err;
 230     }
 231
 232     msg = ossl_cmp_certrep_new(srv_ctx->ctx, bodytype, certReqId, si,
 233                                certOut, chainOut, caPubs, 0 /* encrypted */,
 234                                srv_ctx->sendUnprotectedErrors);
 235     /*
 236      * TODO when implemented in ossl_cmp_certrep_new():
 237      * in case OSSL_CRMF_POPO_KEYENC, set encrypted
 238      */
 239     if (msg == NULL)
 240         CMPerr(0, CMP_R_ERROR_CREATING_CERTREP);
 241
 242  err:
 243     OSSL_CMP_PKISI_free(si);
 244     X509_free(certOut);
 245     sk_X509_pop_free(chainOut, X509_free);
 246     sk_X509_pop_free(caPubs, X509_free);
 247     return msg;
 248 }
 249
 250 static OSSL_CMP_MSG *process_rr(OSSL_CMP_SRV_CTX *srv_ctx,
 251                                 const OSSL_CMP_MSG *req)
 252 {
 253     OSSL_CMP_MSG *msg = NULL;
 254     OSSL_CMP_REVDETAILS *details;
 255     OSSL_CRMF_CERTID *certId;
 256     OSSL_CRMF_CERTTEMPLATE *tmpl;
 257     const X509_NAME *issuer;
 258     ASN1_INTEGER *serial;
 259     OSSL_CMP_PKISI *si;
 260
 261     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
 262         return NULL;
 263
 264     if (sk_OSSL_CMP_REVDETAILS_num(req->body->value.rr) != 1) {
 265         /* TODO: handle multiple elements if multiple requests have been sent */
 266         CMPerr(0, CMP_R_MULTIPLE_REQUESTS_NOT_SUPPORTED);
 267         return NULL;
 268     }
 269
 270     if ((details = sk_OSSL_CMP_REVDETAILS_value(req->body->value.rr,
 271                                                 OSSL_CMP_REVREQSID)) == NULL) {
 272         CMPerr(0, CMP_R_ERROR_PROCESSING_MESSAGE);
 273         return NULL;
 274     }
 275
 276     tmpl = details->certDetails;
 277     issuer = OSSL_CRMF_CERTTEMPLATE_get0_issuer(tmpl);
 278     serial = OSSL_CRMF_CERTTEMPLATE_get0_serialNumber(tmpl);
 279     /* here issuer and serial may safely be NULL */
 280     if ((certId = OSSL_CRMF_CERTID_gen(issuer, serial)) == NULL)
 281         return NULL;
 282     if ((si = srv_ctx->process_rr(srv_ctx, req, issuer, serial)) == NULL)
 283         goto err;
 284
 285     if ((msg = ossl_cmp_rp_new(srv_ctx->ctx, si, certId,
 286                                srv_ctx->sendUnprotectedErrors)) == NULL)
 287         CMPerr(0, CMP_R_ERROR_CREATING_RR);
 288
 289  err:
 290     OSSL_CRMF_CERTID_free(certId);
 291     OSSL_CMP_PKISI_free(si);
 292     return msg;
 293 }
 294
 295 /*
 296  * Processes genm and creates a genp message mirroring the contents of the
 297  * incoming message
 298  */
 299 static OSSL_CMP_MSG *process_genm(OSSL_CMP_SRV_CTX *srv_ctx,
 300                                   const OSSL_CMP_MSG *req)
 301 {
 302     OSSL_CMP_GENMSGCONTENT *itavs;
 303     OSSL_CMP_MSG *msg;
 304
 305     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
 306         return NULL;
 307
 308     if (!srv_ctx->process_genm(srv_ctx, req, req->body->value.genm, &itavs))
 309         return NULL;
 310
 311     msg = ossl_cmp_genp_new(srv_ctx->ctx, itavs);
 312     sk_OSSL_CMP_ITAV_pop_free(itavs, OSSL_CMP_ITAV_free);
 313     return msg;
 314 }
 315
 316 static OSSL_CMP_MSG *process_error(OSSL_CMP_SRV_CTX *srv_ctx,
 317                                    const OSSL_CMP_MSG *req)
 318 {
 319     OSSL_CMP_ERRORMSGCONTENT *errorContent;
 320     OSSL_CMP_MSG *msg;
 321
 322     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
 323         return NULL;
 324     errorContent = req->body->value.error;
 325     srv_ctx->process_error(srv_ctx, req, errorContent->pKIStatusInfo,
 326                            errorContent->errorCode, errorContent->errorDetails);
 327
 328     if ((msg = ossl_cmp_pkiconf_new(srv_ctx->ctx)) == NULL)
 329         CMPerr(0, CMP_R_ERROR_CREATING_PKICONF);
 330     return msg;
 331 }
 332
 333 static OSSL_CMP_MSG *process_certConf(OSSL_CMP_SRV_CTX *srv_ctx,
 334                                       const OSSL_CMP_MSG *req)
 335 {
 336     OSSL_CMP_CTX *ctx;
 337     OSSL_CMP_CERTCONFIRMCONTENT *ccc;
 338     int num;
 339     OSSL_CMP_MSG *msg = NULL;
 340     OSSL_CMP_CERTSTATUS *status = NULL;
 341
 342     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
 343         return NULL;
 344
 345     ctx = srv_ctx->ctx;
 346     ccc = req->body->value.certConf;
 347     num = sk_OSSL_CMP_CERTSTATUS_num(ccc);
 348
 349     if (OSSL_CMP_CTX_get_option(ctx, OSSL_CMP_OPT_IMPLICIT_CONFIRM) == 1) {
 350         CMPerr(0, CMP_R_ERROR_UNEXPECTED_CERTCONF);
 351         return NULL;
 352     }
 353
 354     if (num == 0) {
 355         ossl_cmp_err(ctx, "certificate rejected by client");
 356     } else {
 357         if (num > 1)
 358             ossl_cmp_warn(ctx, "All CertStatus but the first will be ignored");
 359         status = sk_OSSL_CMP_CERTSTATUS_value(ccc, OSSL_CMP_CERTREQID);
 360     }
 361
 362     if (status != NULL) {
 363         int certReqId = ossl_cmp_asn1_get_int(status->certReqId);
 364         ASN1_OCTET_STRING *certHash = status->certHash;
 365         OSSL_CMP_PKISI *si = status->statusInfo;
 366
 367         if (!srv_ctx->process_certConf(srv_ctx, req, certReqId, certHash, si))
 368             return NULL; /* reason code may be: CMP_R_CERTHASH_UNMATCHED */
 369
 370         if (si != NULL && ossl_cmp_pkisi_get_status(si)
 371             != OSSL_CMP_PKISTATUS_accepted) {
 372             int pki_status = ossl_cmp_pkisi_get_status(si);
 373             const char *str = ossl_cmp_PKIStatus_to_string(pki_status);
 374
 375             ossl_cmp_log2(INFO, ctx, "certificate rejected by client %s %s",
 376                           str == NULL ? "without" : "with",
 377                           str == NULL ? "PKIStatus" : str);
 378         }
 379     }
 380
 381     if ((msg = ossl_cmp_pkiconf_new(ctx)) == NULL)
 382         CMPerr(0, CMP_R_ERROR_CREATING_PKICONF);
 383     return msg;
 384 }
 385
 386 static OSSL_CMP_MSG *process_pollReq(OSSL_CMP_SRV_CTX *srv_ctx,
 387                                      const OSSL_CMP_MSG *req)
 388 {
 389     OSSL_CMP_POLLREQCONTENT *prc;
 390     OSSL_CMP_POLLREQ *pr;
 391     int certReqId;
 392     OSSL_CMP_MSG *certReq;
 393     int64_t check_after = 0;
 394     OSSL_CMP_MSG *msg = NULL;
 395
 396     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
 397         return NULL;
 398
 399     prc = req->body->value.pollReq;
 400     if (sk_OSSL_CMP_POLLREQ_num(prc) != 1) { /* TODO: handle case > 1 */
 401         CMPerr(0, CMP_R_MULTIPLE_REQUESTS_NOT_SUPPORTED);
 402         return NULL;
 403     }
 404
 405     pr = sk_OSSL_CMP_POLLREQ_value(prc, 0);
 406     certReqId = ossl_cmp_asn1_get_int(pr->certReqId);
 407     if (!srv_ctx->process_pollReq(srv_ctx, req, certReqId,
 408                                   &certReq, &check_after))
 409         return NULL;
 410
 411     if (certReq != NULL) {
 412         msg = process_cert_request(srv_ctx, certReq);
 413         OSSL_CMP_MSG_free(certReq);
 414     } else {
 415         if ((msg = ossl_cmp_pollRep_new(srv_ctx->ctx, certReqId,
 416                                         check_after)) == NULL)
 417             CMPerr(0, CMP_R_ERROR_CREATING_POLLREP);
 418     }
 419     return msg;
 420 }
 421
 422 /*
 423  * Determine whether missing/invalid protection of request message is allowed.
 424  * Return 1 on acceptance, 0 on rejection, or -1 on (internal) error.
 425  */
 426 static int unprotected_exception(const OSSL_CMP_CTX *ctx,
 427                                  const OSSL_CMP_MSG *req,
 428                                  int invalid_protection,
 429                                  int accept_unprotected_requests)
 430 {
 431     if (!ossl_assert(ctx != NULL && req != NULL))
 432         return -1;
 433
 434     if (accept_unprotected_requests) {
 435         ossl_cmp_log1(WARN, ctx, "ignoring %s protection of request message",
 436                       invalid_protection ? "invalid" : "missing");
 437         return 1;
 438     }
 439     if (ossl_cmp_msg_get_bodytype(req) == OSSL_CMP_PKIBODY_ERROR
 440         && OSSL_CMP_CTX_get_option(ctx, OSSL_CMP_OPT_UNPROTECTED_ERRORS) == 1) {
 441         ossl_cmp_warn(ctx, "ignoring missing protection of error message");
 442         return 1;
 443     }
 444     return 0;
 445 }
 446
 447 /*
 448  * returns created message and NULL on internal error
 449  */
 450 OSSL_CMP_MSG *OSSL_CMP_SRV_process_request(OSSL_CMP_SRV_CTX *srv_ctx,
 451                                            const OSSL_CMP_MSG *req)
 452 {
 453     OSSL_CMP_CTX *ctx;
 454     ASN1_OCTET_STRING *backup_secret;
 455     OSSL_CMP_PKIHEADER *hdr;
 456     int req_type, rsp_type;
 457     int res;
 458     OSSL_CMP_MSG *rsp = NULL;
 459
 460     if (srv_ctx == NULL || srv_ctx->ctx == NULL
 461             || req == NULL || req->body == NULL
 462             || (hdr = OSSL_CMP_MSG_get0_header(req)) == NULL) {
 463         CMPerr(0, CMP_R_NULL_ARGUMENT);
 464         return 0;
 465     }
 466     ctx = srv_ctx->ctx;
 467     backup_secret = ctx->secretValue;
 468
 469     /*
 470      * Some things need to be done already before validating the message in
 471      * order to be able to send an error message as far as needed and possible.
 472      */
 473     if (hdr->sender->type != GEN_DIRNAME) {
 474         CMPerr(0, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 475         goto err;
 476     }
 477     if (!OSSL_CMP_CTX_set1_recipient(ctx, hdr->sender->d.directoryName))
 478         goto err;
 479
 480     req_type = ossl_cmp_msg_get_bodytype(req);
 481     switch (req_type) {
 482     case OSSL_CMP_PKIBODY_IR:
 483     case OSSL_CMP_PKIBODY_CR:
 484     case OSSL_CMP_PKIBODY_P10CR:
 485     case OSSL_CMP_PKIBODY_KUR:
 486     case OSSL_CMP_PKIBODY_RR:
 487     case OSSL_CMP_PKIBODY_GENM:
 488     case OSSL_CMP_PKIBODY_ERROR:
 489         if (ctx->transactionID != NULL) {
 490             char *tid;
 491
 492             tid = OPENSSL_buf2hexstr(ctx->transactionID->data,
 493                                      ctx->transactionID->length);
 494             if (tid != NULL)
 495                 ossl_cmp_log1(WARN, ctx,
 496                               "Assuming that last transaction with ID=%s got aborted",
 497                               tid);
 498             OPENSSL_free(tid);
 499         }
 500         /* start of a new transaction, reset transactionID and senderNonce */
 501         if (!OSSL_CMP_CTX_set1_transactionID(ctx, NULL)
 502                 || !OSSL_CMP_CTX_set1_senderNonce(ctx, NULL))
 503             goto err;
 504         break;
 505     default:
 506         /* transactionID should be already initialized */
 507         if (ctx->transactionID == NULL) {
 508 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 509             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 510             goto err;
 511 #endif
 512         }
 513     }
 514
 515     res = ossl_cmp_msg_check_update(ctx, req, unprotected_exception,
 516                                     srv_ctx->acceptUnprotected);
 517     if (ctx->secretValue != NULL && ctx->pkey != NULL
 518             && ossl_cmp_hdr_get_protection_nid(hdr) != NID_id_PasswordBasedMAC)
 519         ctx->secretValue = NULL; /* use MSG_SIG_ALG when protecting rsp */
 520     if (!res)
 521         goto err;
 522
 523     switch (req_type) {
 524     case OSSL_CMP_PKIBODY_IR:
 525     case OSSL_CMP_PKIBODY_CR:
 526     case OSSL_CMP_PKIBODY_P10CR:
 527     case OSSL_CMP_PKIBODY_KUR:
 528         if (srv_ctx->process_cert_request == NULL)
 529             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 530         else
 531             rsp = process_cert_request(srv_ctx, req);
 532         break;
 533     case OSSL_CMP_PKIBODY_RR:
 534         if (srv_ctx->process_rr == NULL)
 535             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 536         else
 537             rsp = process_rr(srv_ctx, req);
 538         break;
 539     case OSSL_CMP_PKIBODY_GENM:
 540         if (srv_ctx->process_genm == NULL)
 541             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 542         else
 543             rsp = process_genm(srv_ctx, req);
 544         break;
 545     case OSSL_CMP_PKIBODY_ERROR:
 546         if (srv_ctx->process_error == NULL)
 547             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 548         else
 549             rsp = process_error(srv_ctx, req);
 550         break;
 551     case OSSL_CMP_PKIBODY_CERTCONF:
 552         if (srv_ctx->process_certConf == NULL)
 553             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 554         else
 555             rsp = process_certConf(srv_ctx, req);
 556         break;
 557     case OSSL_CMP_PKIBODY_POLLREQ:
 558         if (srv_ctx->process_pollReq == NULL)
 559             CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 560         else
 561             rsp = process_pollReq(srv_ctx, req);
 562         break;
 563     default:
 564         /* TODO possibly support further request message types */
 565         CMPerr(0, CMP_R_UNEXPECTED_PKIBODY);
 566         break;
 567     }
 568
 569  err:
 570     if (rsp == NULL) {
 571         /* on error, try to respond with CMP error message to client */
 572         const char *data = NULL;
 573         int flags = 0;
 574         unsigned long err = ERR_peek_error_data(&data, &flags);
 575         int fail_info = 1 << OSSL_CMP_PKIFAILUREINFO_badRequest;
 576         /* TODO fail_info could be more specific */
 577         OSSL_CMP_PKISI *si = NULL;
 578
 579         if (ctx->transactionID == NULL) {
 580             /* ignore any (extra) error in next two function calls: */
 581             (void)OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID);
 582             (void)ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce);
 583         }
 584
 585         if ((si = OSSL_CMP_STATUSINFO_new(OSSL_CMP_PKISTATUS_rejection,
 586                                           fail_info, NULL)) != NULL) {
 587             if (err != 0 && (flags & ERR_TXT_STRING) != 0)
 588                 data = ERR_reason_error_string(err);
 589             rsp = ossl_cmp_error_new(srv_ctx->ctx, si,
 590                                      err != 0 ? ERR_GET_REASON(err) : -1,
 591                                      data, srv_ctx->sendUnprotectedErrors);
 592             OSSL_CMP_PKISI_free(si);
 593         }
 594     }
 595     ctx->secretValue = backup_secret;
 596
 597     /* possibly close the transaction */
 598     rsp_type =
 599         rsp != NULL ? ossl_cmp_msg_get_bodytype(rsp) : OSSL_CMP_PKIBODY_ERROR;
 600     switch (rsp_type) {
 601     case OSSL_CMP_PKIBODY_IP:
 602     case OSSL_CMP_PKIBODY_CP:
 603     case OSSL_CMP_PKIBODY_KUP:
 604     case OSSL_CMP_PKIBODY_RP:
 605         if (OSSL_CMP_CTX_get_option(ctx, OSSL_CMP_OPT_IMPLICIT_CONFIRM) == 0)
 606             break;
 607         /* fall through */
 608
 609     case OSSL_CMP_PKIBODY_PKICONF:
 610     case OSSL_CMP_PKIBODY_GENP:
 611     case OSSL_CMP_PKIBODY_ERROR:
 612         /* TODO possibly support further terminating response message types */
 613         /* prepare for next transaction, ignoring any errors here: */
 614         (void)OSSL_CMP_CTX_set1_transactionID(ctx, NULL);
 615         (void)OSSL_CMP_CTX_set1_senderNonce(ctx, NULL);
 616
 617     default: /* not closing transaction in other cases */
 618         break;
 619     }
 620     return rsp;
 621 }
 622
 623 /*
 624  * Server interface that may substitute OSSL_CMP_MSG_http_perform at the client.
 625  * The OSSL_CMP_SRV_CTX must be set as client_ctx->transfer_cb_arg.
 626  * returns received message on success, else NULL and pushes an element on the
 627  * error stack.
 628  */
 629 OSSL_CMP_MSG * OSSL_CMP_CTX_server_perform(OSSL_CMP_CTX *client_ctx,
 630                                            const OSSL_CMP_MSG *req)
 631 {
 632     OSSL_CMP_SRV_CTX *srv_ctx = NULL;
 633
 634     if (client_ctx == NULL || req == NULL) {
 635         CMPerr(0, CMP_R_NULL_ARGUMENT);
 636         return 0;
 637     }
 638
 639     if ((srv_ctx = OSSL_CMP_CTX_get_transfer_cb_arg(client_ctx)) == NULL) {
 640         CMPerr(0, CMP_R_TRANSFER_ERROR);
 641         return 0;
 642     }
 643
 644     return OSSL_CMP_SRV_process_request(srv_ctx, req);
 645 }