crypto/cmp/cmp_vfy.c

   1 /*
   2  * Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright Nokia 2007-2020
   4  * Copyright Siemens AG 2015-2020
   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 /* CMP functions for PKIMessage checking */
  13
  14 #include "cmp_local.h"
  15 #include <openssl/cmp_util.h>
  16
  17 /* explicit #includes not strictly needed since implied by the above: */
  18 #include <openssl/asn1t.h>
  19 #include <openssl/cmp.h>
  20 #include <openssl/crmf.h>
  21 #include <openssl/err.h>
  22 #include <openssl/x509.h>
  23
  24 /* Verify a message protected by signature according to RFC section 5.1.3.3 */
  25 static int verify_signature(const OSSL_CMP_CTX *cmp_ctx,
  26                             const OSSL_CMP_MSG *msg, X509 *cert)
  27 {
  28     OSSL_CMP_PROTECTEDPART prot_part;
  29     EVP_PKEY *pubkey = NULL;
  30     BIO *bio = BIO_new(BIO_s_mem()); /* may be NULL */
  31     int res = 0;
  32
  33     if (!ossl_assert(cmp_ctx != NULL && msg != NULL && cert != NULL))
  34         return 0;
  35
  36     /* verify that keyUsage, if present, contains digitalSignature */
  37     if (!cmp_ctx->ignore_keyusage
  38             && (X509_get_key_usage(cert) & X509v3_KU_DIGITAL_SIGNATURE) == 0) {
  39         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_KEY_USAGE_DIGITALSIGNATURE);
  40         goto sig_err;
  41     }
  42
  43     pubkey = X509_get_pubkey(cert);
  44     if (pubkey == NULL) {
  45         ERR_raise(ERR_LIB_CMP, CMP_R_FAILED_EXTRACTING_PUBKEY);
  46         goto sig_err;
  47     }
  48
  49     prot_part.header = msg->header;
  50     prot_part.body = msg->body;
  51
  52     if (ASN1_item_verify_ex(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART),
  53                             msg->header->protectionAlg, msg->protection,
  54                             &prot_part, NULL, pubkey, cmp_ctx->libctx,
  55                             cmp_ctx->propq) > 0) {
  56         res = 1;
  57         goto end;
  58     }
  59
  60  sig_err:
  61     res = ossl_x509_print_ex_brief(bio, cert, X509_FLAG_NO_EXTENSIONS);
  62     ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_SIGNATURE);
  63     if (res)
  64         ERR_add_error_mem_bio("\n", bio);
  65     res = 0;
  66
  67  end:
  68     EVP_PKEY_free(pubkey);
  69     BIO_free(bio);
  70
  71     return res;
  72 }
  73
  74 /* Verify a message protected with PBMAC */
  75 static int verify_PBMAC(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
  76 {
  77     ASN1_BIT_STRING *protection = NULL;
  78     int valid = 0;
  79
  80     /* generate expected protection for the message */
  81     if ((protection = ossl_cmp_calc_protection(ctx, msg)) == NULL)
  82         return 0; /* failed to generate protection string! */
  83
  84     valid = msg->protection != NULL && msg->protection->length >= 0
  85             && msg->protection->type == protection->type
  86             && msg->protection->length == protection->length
  87             && CRYPTO_memcmp(msg->protection->data, protection->data,
  88                              protection->length) == 0;
  89     ASN1_BIT_STRING_free(protection);
  90     if (!valid)
  91         ERR_raise(ERR_LIB_CMP, CMP_R_WRONG_PBM_VALUE);
  92
  93     return valid;
  94 }
  95
  96 /*-
  97  * Attempt to validate certificate and path using any given store with trusted
  98  * certs (possibly including CRLs and a cert verification callback function)
  99  * and non-trusted intermediate certs from the given ctx.
 100  *
 101  * Returns 1 on successful validation and 0 otherwise.
 102  */
 103 int OSSL_CMP_validate_cert_path(const OSSL_CMP_CTX *ctx,
 104                                 X509_STORE *trusted_store, X509 *cert)
 105 {
 106     int valid = 0;
 107     X509_STORE_CTX *csc = NULL;
 108     int err;
 109
 110     if (ctx == NULL || cert == NULL) {
 111         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
 112         return 0;
 113     }
 114
 115     if (trusted_store == NULL) {
 116         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_STORE);
 117         return 0;
 118     }
 119
 120     if ((csc = X509_STORE_CTX_new_ex(ctx->libctx, ctx->propq)) == NULL
 121             || !X509_STORE_CTX_init(csc, trusted_store,
 122                                     cert, ctx->untrusted))
 123         goto err;
 124
 125     valid = X509_verify_cert(csc) > 0;
 126
 127     /* make sure suitable error is queued even if callback did not do */
 128     err = ERR_peek_last_error();
 129     if (!valid && ERR_GET_REASON(err) != CMP_R_POTENTIALLY_INVALID_CERTIFICATE)
 130         ERR_raise(ERR_LIB_CMP, CMP_R_POTENTIALLY_INVALID_CERTIFICATE);
 131
 132  err:
 133     /* directly output any fresh errors, needed for check_msg_find_cert() */
 134     OSSL_CMP_CTX_print_errors(ctx);
 135     X509_STORE_CTX_free(csc);
 136     return valid;
 137 }
 138
 139 /* Return 0 if expect_name != NULL and there is no matching actual_name */
 140 static int check_name(const OSSL_CMP_CTX *ctx, int log_success,
 141                       const char *actual_desc, const X509_NAME *actual_name,
 142                       const char *expect_desc, const X509_NAME *expect_name)
 143 {
 144     char *str;
 145
 146     if (expect_name == NULL)
 147         return 1; /* no expectation, thus trivially fulfilled */
 148
 149     /* make sure that a matching name is there */
 150     if (actual_name == NULL) {
 151         ossl_cmp_log1(WARN, ctx, "missing %s", actual_desc);
 152         return 0;
 153     }
 154     str = X509_NAME_oneline(actual_name, NULL, 0);
 155     if (X509_NAME_cmp(actual_name, expect_name) == 0) {
 156         if (log_success && str != NULL)
 157             ossl_cmp_log2(INFO, ctx, " subject matches %s: %s", expect_desc,
 158                           str);
 159         OPENSSL_free(str);
 160         return 1;
 161     }
 162
 163     if (str != NULL)
 164         ossl_cmp_log2(INFO, ctx, " actual name in %s = %s", actual_desc, str);
 165     OPENSSL_free(str);
 166     if ((str = X509_NAME_oneline(expect_name, NULL, 0)) != NULL)
 167         ossl_cmp_log2(INFO, ctx, " does not match %s = %s", expect_desc, str);
 168     OPENSSL_free(str);
 169     return 0;
 170 }
 171
 172 /* Return 0 if skid != NULL and there is no matching subject key ID in cert */
 173 static int check_kid(const OSSL_CMP_CTX *ctx,
 174                      const ASN1_OCTET_STRING *ckid,
 175                      const ASN1_OCTET_STRING *skid)
 176 {
 177     char *str;
 178
 179     if (skid == NULL)
 180         return 1; /* no expectation, thus trivially fulfilled */
 181
 182     /* make sure that the expected subject key identifier is there */
 183     if (ckid == NULL) {
 184         ossl_cmp_warn(ctx, "missing Subject Key Identifier in certificate");
 185         return 0;
 186     }
 187     str = OPENSSL_buf2hexstr(ckid->data, ckid->length);
 188     if (ASN1_OCTET_STRING_cmp(ckid, skid) == 0) {
 189         if (str != NULL)
 190             ossl_cmp_log1(INFO, ctx, " subjectKID matches senderKID: %s", str);
 191         OPENSSL_free(str);
 192         return 1;
 193     }
 194
 195     if (str != NULL)
 196         ossl_cmp_log1(INFO, ctx, " cert Subject Key Identifier = %s", str);
 197     OPENSSL_free(str);
 198     if ((str = OPENSSL_buf2hexstr(skid->data, skid->length)) != NULL)
 199         ossl_cmp_log1(INFO, ctx, " does not match senderKID    = %s", str);
 200     OPENSSL_free(str);
 201     return 0;
 202 }
 203
 204 static int already_checked(const X509 *cert,
 205                            const STACK_OF(X509) *already_checked)
 206 {
 207     int i;
 208
 209     for (i = sk_X509_num(already_checked /* may be NULL */); i > 0; i--)
 210         if (X509_cmp(sk_X509_value(already_checked, i - 1), cert) == 0)
 211             return 1;
 212     return 0;
 213 }
 214
 215 /*-
 216  * Check if the given cert is acceptable as sender cert of the given message.
 217  * The subject DN must match, the subject key ID as well if present in the msg,
 218  * and the cert must be current (checked if ctx->trusted is not NULL).
 219  * Note that cert revocation etc. is checked by OSSL_CMP_validate_cert_path().
 220  *
 221  * Returns 0 on error or not acceptable, else 1.
 222  */
 223 static int cert_acceptable(const OSSL_CMP_CTX *ctx,
 224                            const char *desc1, const char *desc2, X509 *cert,
 225                            const STACK_OF(X509) *already_checked1,
 226                            const STACK_OF(X509) *already_checked2,
 227                            const OSSL_CMP_MSG *msg)
 228 {
 229     X509_STORE *ts = ctx->trusted;
 230     int self_issued = X509_check_issued(cert, cert) == X509_V_OK;
 231     char *str;
 232     X509_VERIFY_PARAM *vpm = ts != NULL ? X509_STORE_get0_param(ts) : NULL;
 233     int time_cmp;
 234
 235     ossl_cmp_log3(INFO, ctx, " considering %s%s %s with..",
 236                   self_issued ? "self-issued ": "", desc1, desc2);
 237     if ((str = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0)) != NULL)
 238         ossl_cmp_log1(INFO, ctx, "  subject = %s", str);
 239     OPENSSL_free(str);
 240     if (!self_issued) {
 241         str = X509_NAME_oneline(X509_get_issuer_name(cert), NULL, 0);
 242         if (str != NULL)
 243             ossl_cmp_log1(INFO, ctx, "  issuer  = %s", str);
 244         OPENSSL_free(str);
 245     }
 246
 247     if (already_checked(cert, already_checked1)
 248             || already_checked(cert, already_checked2)) {
 249         ossl_cmp_info(ctx, " cert has already been checked");
 250         return 0;
 251     }
 252
 253     time_cmp = X509_cmp_timeframe(vpm, X509_get0_notBefore(cert),
 254                                   X509_get0_notAfter(cert));
 255     if (time_cmp != 0) {
 256         ossl_cmp_warn(ctx, time_cmp > 0 ? "cert has expired"
 257                                         : "cert is not yet valid");
 258         return 0;
 259     }
 260
 261     if (!check_name(ctx, 1,
 262                     "cert subject", X509_get_subject_name(cert),
 263                     "sender field", msg->header->sender->d.directoryName))
 264         return 0;
 265
 266     if (!check_kid(ctx, X509_get0_subject_key_id(cert), msg->header->senderKID))
 267         return 0;
 268     /* prevent misleading error later in case x509v3_cache_extensions() fails */
 269     if (!ossl_x509v3_cache_extensions(cert)) {
 270         ossl_cmp_warn(ctx, "cert appears to be invalid");
 271         return 0;
 272     }
 273     if (!verify_signature(ctx, msg, cert)) {
 274         ossl_cmp_warn(ctx, "msg signature verification failed");
 275         return 0;
 276     }
 277     /* acceptable also if there is no senderKID in msg header */
 278     ossl_cmp_info(ctx, " cert seems acceptable");
 279     return 1;
 280 }
 281
 282 static int check_cert_path(const OSSL_CMP_CTX *ctx, X509_STORE *store,
 283                            X509 *scrt)
 284 {
 285     if (OSSL_CMP_validate_cert_path(ctx, store, scrt))
 286         return 1;
 287
 288     ossl_cmp_warn(ctx,
 289                   "msg signature validates but cert path validation failed");
 290     return 0;
 291 }
 292
 293 /*
 294  * Exceptional handling for 3GPP TS 33.310 [3G/LTE Network Domain Security
 295  * (NDS); Authentication Framework (AF)], only to use for IP messages
 296  * and if the ctx option is explicitly set: use self-issued certificates
 297  * from extraCerts as trust anchor to validate sender cert -
 298  * provided it also can validate the newly enrolled certificate
 299  */
 300 static int check_cert_path_3gpp(const OSSL_CMP_CTX *ctx,
 301                                 const OSSL_CMP_MSG *msg, X509 *scrt)
 302 {
 303     int valid = 0;
 304     X509_STORE *store;
 305
 306     if (!ctx->permitTAInExtraCertsForIR)
 307         return 0;
 308
 309     if ((store = X509_STORE_new()) == NULL
 310             || !ossl_cmp_X509_STORE_add1_certs(store, msg->extraCerts,
 311                                                1 /* self-issued only */))
 312         goto err;
 313
 314     /* store does not include CRLs */
 315     valid = OSSL_CMP_validate_cert_path(ctx, store, scrt);
 316     if (!valid) {
 317         ossl_cmp_warn(ctx,
 318                       "also exceptional 3GPP mode cert path validation failed");
 319     } else {
 320         /*
 321          * verify that the newly enrolled certificate (which assumed rid ==
 322          * OSSL_CMP_CERTREQID) can also be validated with the same trusted store
 323          */
 324         EVP_PKEY *pkey = OSSL_CMP_CTX_get0_newPkey(ctx, 1);
 325         OSSL_CMP_CERTRESPONSE *crep =
 326             ossl_cmp_certrepmessage_get0_certresponse(msg->body->value.ip,
 327                                                       OSSL_CMP_CERTREQID);
 328         X509 *newcrt = ossl_cmp_certresponse_get1_cert(crep, ctx, pkey);
 329         /*
 330          * maybe better use get_cert_status() from cmp_client.c, which catches
 331          * errors
 332          */
 333         valid = OSSL_CMP_validate_cert_path(ctx, store, newcrt);
 334         X509_free(newcrt);
 335     }
 336
 337  err:
 338     X509_STORE_free(store);
 339     return valid;
 340 }
 341
 342 static int check_msg_given_cert(const OSSL_CMP_CTX *ctx, X509 *cert,
 343                                 const OSSL_CMP_MSG *msg)
 344 {
 345     return cert_acceptable(ctx, "previously validated", "sender cert",
 346                            cert, NULL, NULL, msg)
 347         && (check_cert_path(ctx, ctx->trusted, cert)
 348             || check_cert_path_3gpp(ctx, msg, cert));
 349 }
 350
 351 /*-
 352  * Try all certs in given list for verifying msg, normally or in 3GPP mode.
 353  * If already_checked1 == NULL then certs are assumed to be the msg->extraCerts.
 354  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 355  */
 356 static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,
 357                                 const char *desc,
 358                                 const STACK_OF(X509) *already_checked1,
 359                                 const STACK_OF(X509) *already_checked2,
 360                                 const OSSL_CMP_MSG *msg, int mode_3gpp)
 361 {
 362     int in_extraCerts = already_checked1 == NULL;
 363     int n_acceptable_certs = 0;
 364     int i;
 365
 366     if (sk_X509_num(certs) <= 0) {
 367         ossl_cmp_log1(WARN, ctx, "no %s", desc);
 368         return 0;
 369     }
 370
 371     for (i = 0; i < sk_X509_num(certs); i++) { /* certs may be NULL */
 372         X509 *cert = sk_X509_value(certs, i);
 373
 374         if (!ossl_assert(cert != NULL))
 375             return 0;
 376         if (!cert_acceptable(ctx, "cert from", desc, cert,
 377                              already_checked1, already_checked2, msg))
 378             continue;
 379         n_acceptable_certs++;
 380         if (mode_3gpp ? check_cert_path_3gpp(ctx, msg, cert)
 381                       : check_cert_path(ctx, ctx->trusted, cert)) {
 382             /* store successful sender cert for further msgs in transaction */
 383             if (!X509_up_ref(cert))
 384                 return 0;
 385             if (!ossl_cmp_ctx_set0_validatedSrvCert(ctx, cert)) {
 386                 X509_free(cert);
 387                 return 0;
 388             }
 389             return 1;
 390         }
 391     }
 392     if (in_extraCerts && n_acceptable_certs == 0)
 393         ossl_cmp_warn(ctx, "no acceptable cert in extraCerts");
 394     return 0;
 395 }
 396
 397 /*-
 398  * Verify msg trying first ctx->untrusted, which should include extraCerts
 399  * at its front, then trying the trusted certs in truststore (if any) of ctx.
 400  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 401  */
 402 static int check_msg_all_certs(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 403                                int mode_3gpp)
 404 {
 405     int ret = 0;
 406
 407     if (mode_3gpp
 408             && ((!ctx->permitTAInExtraCertsForIR
 409                      || OSSL_CMP_MSG_get_bodytype(msg) != OSSL_CMP_PKIBODY_IP)))
 410         return 0;
 411
 412     ossl_cmp_info(ctx,
 413                   mode_3gpp ? "normal mode failed; trying now 3GPP mode trusting extraCerts"
 414                             : "trying first normal mode using trust store");
 415     if (check_msg_with_certs(ctx, msg->extraCerts, "extraCerts",
 416                              NULL, NULL, msg, mode_3gpp))
 417         return 1;
 418     if (check_msg_with_certs(ctx, ctx->untrusted, "untrusted certs",
 419                              msg->extraCerts, NULL, msg, mode_3gpp))
 420         return 1;
 421
 422     if (ctx->trusted == NULL) {
 423         ossl_cmp_warn(ctx, mode_3gpp ? "no self-issued extraCerts"
 424                                      : "no trusted store");
 425     } else {
 426         STACK_OF(X509) *trusted = X509_STORE_get1_all_certs(ctx->trusted);
 427         ret = check_msg_with_certs(ctx, trusted,
 428                                    mode_3gpp ? "self-issued extraCerts"
 429                                              : "certs in trusted store",
 430                                    msg->extraCerts, ctx->untrusted,
 431                                    msg, mode_3gpp);
 432         sk_X509_pop_free(trusted, X509_free);
 433     }
 434     return ret;
 435 }
 436
 437 static int no_log_cb(const char *func, const char *file, int line,
 438                      OSSL_CMP_severity level, const char *msg)
 439 {
 440     return 1;
 441 }
 442
 443 /*-
 444  * Verify message signature with any acceptable and valid candidate cert.
 445  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 446  */
 447 static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 448 {
 449     X509 *scrt = ctx->validatedSrvCert; /* previous successful sender cert */
 450     GENERAL_NAME *sender = msg->header->sender;
 451     char *sname = NULL;
 452     char *skid_str = NULL;
 453     const ASN1_OCTET_STRING *skid = msg->header->senderKID;
 454     OSSL_CMP_log_cb_t backup_log_cb = ctx->log_cb;
 455     int res = 0;
 456
 457     if (sender == NULL || msg->body == NULL)
 458         return 0; /* other NULL cases already have been checked */
 459     if (sender->type != GEN_DIRNAME) {
 460         ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 461         return 0;
 462     }
 463
 464     /* dump any hitherto errors to avoid confusion when printing further ones */
 465     OSSL_CMP_CTX_print_errors(ctx);
 466
 467     /* enable clearing irrelevant errors in attempts to validate sender certs */
 468     (void)ERR_set_mark();
 469     ctx->log_cb = no_log_cb; /* temporarily disable logging */
 470
 471     /*
 472      * try first cached scrt, used successfully earlier in same transaction,
 473      * for validating this and any further msgs where extraCerts may be left out
 474      */
 475     if (scrt != NULL) {
 476         if (check_msg_given_cert(ctx, scrt, msg)) {
 477             ctx->log_cb = backup_log_cb;
 478             (void)ERR_pop_to_mark();
 479             return 1;
 480         }
 481         /* cached sender cert has shown to be no more successfully usable */
 482         (void)ossl_cmp_ctx_set0_validatedSrvCert(ctx, NULL);
 483         /* re-do the above check (just) for adding diagnostic information */
 484         ossl_cmp_info(ctx,
 485                       "trying to verify msg signature with previously validated cert");
 486         (void)check_msg_given_cert(ctx, scrt, msg);
 487     }
 488
 489     res = check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */)
 490             || check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 491     ctx->log_cb = backup_log_cb;
 492     if (res) {
 493         /* discard any diagnostic information on trying to use certs */
 494         (void)ERR_pop_to_mark();
 495         goto end;
 496     }
 497     /* failed finding a sender cert that verifies the message signature */
 498     (void)ERR_clear_last_mark();
 499
 500     sname = X509_NAME_oneline(sender->d.directoryName, NULL, 0);
 501     skid_str = skid == NULL ? NULL
 502                             : OPENSSL_buf2hexstr(skid->data, skid->length);
 503     if (ctx->log_cb != NULL) {
 504         ossl_cmp_info(ctx, "trying to verify msg signature with a valid cert that..");
 505         if (sname != NULL)
 506             ossl_cmp_log1(INFO, ctx, "matches msg sender    = %s", sname);
 507         if (skid_str != NULL)
 508             ossl_cmp_log1(INFO, ctx, "matches msg senderKID = %s", skid_str);
 509         else
 510             ossl_cmp_info(ctx, "while msg header does not contain senderKID");
 511         /* re-do the above checks (just) for adding diagnostic information */
 512         (void)check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */);
 513         (void)check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 514     }
 515
 516     ERR_raise(ERR_LIB_CMP, CMP_R_NO_SUITABLE_SENDER_CERT);
 517     if (sname != NULL) {
 518         ERR_add_error_txt(NULL, "for msg sender name = ");
 519         ERR_add_error_txt(NULL, sname);
 520     }
 521     if (skid_str != NULL) {
 522         ERR_add_error_txt(" and ", "for msg senderKID = ");
 523         ERR_add_error_txt(NULL, skid_str);
 524     }
 525
 526  end:
 527     OPENSSL_free(sname);
 528     OPENSSL_free(skid_str);
 529     return res;
 530 }
 531
 532 /*-
 533  * Validate the protection of the given PKIMessage using either password-
 534  * based mac (PBM) or a signature algorithm. In the case of signature algorithm,
 535  * the sender certificate can have been pinned by providing it in ctx->srvCert,
 536  * else it is searched in msg->extraCerts, ctx->untrusted, in ctx->trusted
 537  * (in this order) and is path is validated against ctx->trusted.
 538  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 539  *
 540  * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,
 541  * the trust anchor for validating the IP msg may be taken from msg->extraCerts
 542  * if a self-issued certificate is found there that can be used to
 543  * validate the enrolled certificate returned in the IP.
 544  * This is according to the need given in 3GPP TS 33.310.
 545  *
 546  * Returns 1 on success, 0 on error or validation failed.
 547  */
 548 int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 549 {
 550     X509 *scrt;
 551
 552     ossl_cmp_debug(ctx, "validating CMP message");
 553     if (ctx == NULL || msg == NULL
 554             || msg->header == NULL || msg->body == NULL) {
 555         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
 556         return 0;
 557     }
 558
 559     if (msg->header->protectionAlg == NULL /* unprotected message */
 560             || msg->protection == NULL || msg->protection->data == NULL) {
 561         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);
 562         return 0;
 563     }
 564
 565     switch (ossl_cmp_hdr_get_protection_nid(msg->header)) {
 566         /* 5.1.3.1.  Shared Secret Information */
 567     case NID_id_PasswordBasedMAC:
 568         if (ctx->secretValue == NULL) {
 569             ossl_cmp_warn(ctx, "no secret available for verifying PBM-based CMP message protection");
 570             return 1;
 571         }
 572         if (verify_PBMAC(ctx, msg)) {
 573             /*
 574              * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
 575              * "shared secret information", then any certificate transported in
 576              * the caPubs field may be directly trusted as a root CA
 577              * certificate by the initiator.'
 578              */
 579             switch (OSSL_CMP_MSG_get_bodytype(msg)) {
 580             case -1:
 581                 return 0;
 582             case OSSL_CMP_PKIBODY_IP:
 583             case OSSL_CMP_PKIBODY_CP:
 584             case OSSL_CMP_PKIBODY_KUP:
 585             case OSSL_CMP_PKIBODY_CCP:
 586                 if (ctx->trusted != NULL) {
 587                     STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
 588                     /* value.ip is same for cp, kup, and ccp */
 589
 590                     if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
 591                         /* adds both self-issued and not self-issued certs */
 592                         return 0;
 593                 }
 594                 break;
 595             default:
 596                 break;
 597             }
 598             ossl_cmp_debug(ctx,
 599                            "sucessfully validated PBM-based CMP message protection");
 600             return 1;
 601         }
 602         ossl_cmp_warn(ctx, "verifying PBM-based CMP message protection failed");
 603         break;
 604
 605         /*
 606          * 5.1.3.2 DH Key Pairs
 607          * Not yet supported
 608          */
 609     case NID_id_DHBasedMac:
 610         ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PROTECTION_ALG_DHBASEDMAC);
 611         break;
 612
 613         /*
 614          * 5.1.3.3.  Signature
 615          */
 616     default:
 617         scrt = ctx->srvCert;
 618         if (scrt == NULL) {
 619             if (ctx->trusted == NULL) {
 620                 ossl_cmp_warn(ctx, "no trust store nor pinned server cert available for verifying signature-based CMP message protection");
 621                 return 1;
 622             }
 623             if (check_msg_find_cert(ctx, msg))
 624                 return 1;
 625         } else { /* use pinned sender cert */
 626             /* use ctx->srvCert for signature check even if not acceptable */
 627             if (verify_signature(ctx, msg, scrt)) {
 628                 ossl_cmp_debug(ctx,
 629                                "sucessfully validated signature-based CMP message protection");
 630
 631                 return 1;
 632             }
 633             ossl_cmp_warn(ctx, "CMP message signature verification failed");
 634             ERR_raise(ERR_LIB_CMP, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);
 635         }
 636         break;
 637     }
 638     return 0;
 639 }
 640
 641
 642 /*-
 643  * Check received message (i.e., response by server or request from client)
 644  * Any msg->extraCerts are prepended to ctx->untrusted.
 645  *
 646  * Ensures that:
 647  * its sender is of appropriate type (curently only X509_NAME) and
 648  *     matches any expected sender or srvCert subject given in the ctx
 649  * it has a valid body type
 650  * its protection is valid (or invalid/absent, but only if a callback function
 651  *     is present and yields a positive result using also the supplied argument)
 652  * its transaction ID matches the previous transaction ID stored in ctx (if any)
 653  * its recipNonce matches the previous senderNonce stored in the ctx (if any)
 654  *
 655  * If everything is fine:
 656  * learns the senderNonce from the received message,
 657  * learns the transaction ID if it is not yet in ctx,
 658  * and makes any certs in caPubs directly trusted.
 659  *
 660  * Returns 1 on success, 0 on error.
 661  */
 662 int ossl_cmp_msg_check_update(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 663                               ossl_cmp_allow_unprotected_cb_t cb, int cb_arg)
 664 {
 665     OSSL_CMP_PKIHEADER *hdr;
 666     const X509_NAME *expected_sender;
 667
 668     if (!ossl_assert(ctx != NULL && msg != NULL && msg->header != NULL))
 669         return 0;
 670     hdr = OSSL_CMP_MSG_get0_header(msg);
 671
 672     /* validate sender name of received msg */
 673     if (hdr->sender->type != GEN_DIRNAME) {
 674         ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 675         return 0;
 676     }
 677     /*
 678      * Compare actual sender name of response with expected sender name.
 679      * Mitigates risk to accept misused PBM secret
 680      * or misused certificate of an unauthorized entity of a trusted hierarchy.
 681      */
 682     expected_sender = ctx->expected_sender;
 683     if (expected_sender == NULL && ctx->srvCert != NULL)
 684         expected_sender = X509_get_subject_name(ctx->srvCert);
 685     if (!check_name(ctx, 0, "sender DN field", hdr->sender->d.directoryName,
 686                     "expected sender", expected_sender))
 687         return 0;
 688     /* Note: if recipient was NULL-DN it could be learned here if needed */
 689
 690     if (sk_X509_num(msg->extraCerts) > 10)
 691         ossl_cmp_warn(ctx,
 692                       "received CMP message contains more than 10 extraCerts");
 693     /*
 694      * Store any provided extraCerts in ctx for use in OSSL_CMP_validate_msg()
 695      * and for future use, such that they are available to ctx->certConf_cb and
 696      * the peer does not need to send them again in the same transaction.
 697      * Note that it does not help validating the message before storing the
 698      * extraCerts because they do not belong to the protected msg part anyway.
 699      * For efficiency, the extraCerts are prepended so they get used first.
 700      */
 701     if (!X509_add_certs(ctx->untrusted, msg->extraCerts,
 702                         /* this allows self-signed certs */
 703                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 704                         | X509_ADD_FLAG_PREPEND))
 705         return 0;
 706
 707     /* validate message protection */
 708     if (hdr->protectionAlg != NULL) {
 709         /* detect explicitly permitted exceptions for invalid protection */
 710         if (!OSSL_CMP_validate_msg(ctx, msg)
 711                 && (cb == NULL || (*cb)(ctx, msg, 1, cb_arg) <= 0)) {
 712 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 713             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_PROTECTION);
 714             return 0;
 715 #endif
 716         }
 717     } else {
 718         /* detect explicitly permitted exceptions for missing protection */
 719         if (cb == NULL || (*cb)(ctx, msg, 0, cb_arg) <= 0) {
 720 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 721             ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);
 722             return 0;
 723 #endif
 724         }
 725     }
 726
 727     /* check CMP version number in header */
 728     if (ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO) {
 729 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 730         ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PVNO);
 731         return 0;
 732 #endif
 733     }
 734
 735     if (OSSL_CMP_MSG_get_bodytype(msg) < 0) {
 736 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 737         ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);
 738         return 0;
 739 #endif
 740     }
 741
 742     /* compare received transactionID with the expected one in previous msg */
 743     if (ctx->transactionID != NULL
 744             && (hdr->transactionID == NULL
 745                 || ASN1_OCTET_STRING_cmp(ctx->transactionID,
 746                                          hdr->transactionID) != 0)) {
 747 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 748         ERR_raise(ERR_LIB_CMP, CMP_R_TRANSACTIONID_UNMATCHED);
 749         return 0;
 750 #endif
 751     }
 752
 753     /* compare received nonce with the one we sent */
 754     if (ctx->senderNonce != NULL
 755             && (msg->header->recipNonce == NULL
 756                 || ASN1_OCTET_STRING_cmp(ctx->senderNonce,
 757                                          hdr->recipNonce) != 0)) {
 758 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 759         ERR_raise(ERR_LIB_CMP, CMP_R_RECIPNONCE_UNMATCHED);
 760         return 0;
 761 #endif
 762     }
 763
 764     /*
 765      * RFC 4210 section 5.1.1 states: the recipNonce is copied from
 766      * the senderNonce of the previous message in the transaction.
 767      * --> Store for setting in next message
 768      */
 769     if (!ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce))
 770         return 0;
 771
 772     /* if not yet present, learn transactionID */
 773     if (ctx->transactionID == NULL
 774         && !OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID))
 775         return -1;
 776
 777     /*
 778      * Store any provided extraCerts in ctx for future use,
 779      * such that they are available to ctx->certConf_cb and
 780      * the peer does not need to send them again in the same transaction.
 781      * For efficiency, the extraCerts are prepended so they get used first.
 782      */
 783     if (!X509_add_certs(ctx->untrusted, msg->extraCerts,
 784                         /* this allows self-signed certs */
 785                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 786                         | X509_ADD_FLAG_PREPEND))
 787         return -1;
 788
 789     if (ossl_cmp_hdr_get_protection_nid(hdr) == NID_id_PasswordBasedMAC) {
 790         /*
 791          * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
 792          * "shared secret information", then any certificate transported in
 793          * the caPubs field may be directly trusted as a root CA
 794          * certificate by the initiator.'
 795          */
 796         switch (OSSL_CMP_MSG_get_bodytype(msg)) {
 797         case OSSL_CMP_PKIBODY_IP:
 798         case OSSL_CMP_PKIBODY_CP:
 799         case OSSL_CMP_PKIBODY_KUP:
 800         case OSSL_CMP_PKIBODY_CCP:
 801             if (ctx->trusted != NULL) {
 802                 STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
 803                 /* value.ip is same for cp, kup, and ccp */
 804
 805                 if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
 806                     /* adds both self-issued and not self-issued certs */
 807                     return 0;
 808             }
 809             break;
 810         default:
 811             break;
 812         }
 813     }
 814     return 1;
 815 }
 816
 817 int ossl_cmp_verify_popo(const OSSL_CMP_CTX *ctx,
 818                          const OSSL_CMP_MSG *msg, int acceptRAVerified)
 819 {
 820     if (!ossl_assert(msg != NULL && msg->body != NULL))
 821         return 0;
 822     switch (msg->body->type) {
 823     case OSSL_CMP_PKIBODY_P10CR:
 824         {
 825             X509_REQ *req = msg->body->value.p10cr;
 826
 827             if (X509_REQ_verify_ex(req, X509_REQ_get0_pubkey(req), ctx->libctx,
 828                                    ctx->propq) <= 0) {
 829 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 830                 ERR_raise(ERR_LIB_CMP, CMP_R_REQUEST_NOT_ACCEPTED);
 831                 return 0;
 832 #endif
 833             }
 834         }
 835         break;
 836     case OSSL_CMP_PKIBODY_IR:
 837     case OSSL_CMP_PKIBODY_CR:
 838     case OSSL_CMP_PKIBODY_KUR:
 839         if (!OSSL_CRMF_MSGS_verify_popo(msg->body->value.ir, OSSL_CMP_CERTREQID,
 840                                         acceptRAVerified,
 841                                         ctx->libctx, ctx->propq)) {
 842 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 843             return 0;
 844 #endif
 845         }
 846         break;
 847     default:
 848         ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);
 849         return 0;
 850     }
 851     return 1;
 852 }