crypto/cmp/cmp_vfy.c

   1 /*
   2  * Copyright 2007-2022 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;
  31     int res = 0;
  32
  33     if (!ossl_assert(cmp_ctx != NULL && msg != NULL && cert != NULL))
  34         return 0;
  35
  36     bio = BIO_new(BIO_s_mem()); /* may be NULL */
  37     if (bio == NULL)
  38         return 0;
  39     /* verify that keyUsage, if present, contains digitalSignature */
  40     if (!cmp_ctx->ignore_keyusage
  41             && (X509_get_key_usage(cert) & X509v3_KU_DIGITAL_SIGNATURE) == 0) {
  42         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_KEY_USAGE_DIGITALSIGNATURE);
  43         goto sig_err;
  44     }
  45
  46     pubkey = X509_get_pubkey(cert);
  47     if (pubkey == NULL) {
  48         ERR_raise(ERR_LIB_CMP, CMP_R_FAILED_EXTRACTING_PUBKEY);
  49         goto sig_err;
  50     }
  51
  52     prot_part.header = msg->header;
  53     prot_part.body = msg->body;
  54
  55     if (ASN1_item_verify_ex(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART),
  56                             msg->header->protectionAlg, msg->protection,
  57                             &prot_part, NULL, pubkey, cmp_ctx->libctx,
  58                             cmp_ctx->propq) > 0) {
  59         res = 1;
  60         goto end;
  61     }
  62
  63  sig_err:
  64     res = ossl_x509_print_ex_brief(bio, cert, X509_FLAG_NO_EXTENSIONS);
  65     ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_SIGNATURE);
  66     if (res)
  67         ERR_add_error_mem_bio("\n", bio);
  68     res = 0;
  69
  70  end:
  71     EVP_PKEY_free(pubkey);
  72     BIO_free(bio);
  73
  74     return res;
  75 }
  76
  77 /* Verify a message protected with PBMAC */
  78 static int verify_PBMAC(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
  79 {
  80     ASN1_BIT_STRING *protection = NULL;
  81     int valid = 0;
  82
  83     /* generate expected protection for the message */
  84     if ((protection = ossl_cmp_calc_protection(ctx, msg)) == NULL)
  85         return 0; /* failed to generate protection string! */
  86
  87     valid = msg->protection != NULL && msg->protection->length >= 0
  88             && msg->protection->type == protection->type
  89             && msg->protection->length == protection->length
  90             && CRYPTO_memcmp(msg->protection->data, protection->data,
  91                              protection->length) == 0;
  92     ASN1_BIT_STRING_free(protection);
  93     if (!valid)
  94         ERR_raise(ERR_LIB_CMP, CMP_R_WRONG_PBM_VALUE);
  95
  96     return valid;
  97 }
  98
  99 /*-
 100  * Attempt to validate certificate and path using any given store with trusted
 101  * certs (possibly including CRLs and a cert verification callback function)
 102  * and non-trusted intermediate certs from the given ctx.
 103  *
 104  * Returns 1 on successful validation and 0 otherwise.
 105  */
 106 int OSSL_CMP_validate_cert_path(const OSSL_CMP_CTX *ctx,
 107                                 X509_STORE *trusted_store, X509 *cert)
 108 {
 109     int valid = 0;
 110     X509_STORE_CTX *csc = NULL;
 111     int err;
 112
 113     if (ctx == NULL || cert == NULL) {
 114         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
 115         return 0;
 116     }
 117
 118     if (trusted_store == NULL) {
 119         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_STORE);
 120         return 0;
 121     }
 122
 123     if ((csc = X509_STORE_CTX_new_ex(ctx->libctx, ctx->propq)) == NULL
 124             || !X509_STORE_CTX_init(csc, trusted_store,
 125                                     cert, ctx->untrusted))
 126         goto err;
 127
 128     valid = X509_verify_cert(csc) > 0;
 129
 130     /* make sure suitable error is queued even if callback did not do */
 131     err = ERR_peek_last_error();
 132     if (!valid && ERR_GET_REASON(err) != CMP_R_POTENTIALLY_INVALID_CERTIFICATE)
 133         ERR_raise(ERR_LIB_CMP, CMP_R_POTENTIALLY_INVALID_CERTIFICATE);
 134
 135  err:
 136     /* directly output any fresh errors, needed for check_msg_find_cert() */
 137     OSSL_CMP_CTX_print_errors(ctx);
 138     X509_STORE_CTX_free(csc);
 139     return valid;
 140 }
 141
 142 /* Return 0 if expect_name != NULL and there is no matching actual_name */
 143 static int check_name(const OSSL_CMP_CTX *ctx, int log_success,
 144                       const char *actual_desc, const X509_NAME *actual_name,
 145                       const char *expect_desc, const X509_NAME *expect_name)
 146 {
 147     char *str;
 148
 149     if (expect_name == NULL)
 150         return 1; /* no expectation, thus trivially fulfilled */
 151
 152     /* make sure that a matching name is there */
 153     if (actual_name == NULL) {
 154         ossl_cmp_log1(WARN, ctx, "missing %s", actual_desc);
 155         return 0;
 156     }
 157     str = X509_NAME_oneline(actual_name, NULL, 0);
 158     if (X509_NAME_cmp(actual_name, expect_name) == 0) {
 159         if (log_success && str != NULL)
 160             ossl_cmp_log2(INFO, ctx, " subject matches %s: %s", expect_desc,
 161                           str);
 162         OPENSSL_free(str);
 163         return 1;
 164     }
 165
 166     if (str != NULL)
 167         ossl_cmp_log2(INFO, ctx, " actual name in %s = %s", actual_desc, str);
 168     OPENSSL_free(str);
 169     if ((str = X509_NAME_oneline(expect_name, NULL, 0)) != NULL)
 170         ossl_cmp_log2(INFO, ctx, " does not match %s = %s", expect_desc, str);
 171     OPENSSL_free(str);
 172     return 0;
 173 }
 174
 175 /* Return 0 if skid != NULL and there is no matching subject key ID in cert */
 176 static int check_kid(const OSSL_CMP_CTX *ctx,
 177                      const ASN1_OCTET_STRING *ckid,
 178                      const ASN1_OCTET_STRING *skid)
 179 {
 180     char *str;
 181
 182     if (skid == NULL)
 183         return 1; /* no expectation, thus trivially fulfilled */
 184
 185     /* make sure that the expected subject key identifier is there */
 186     if (ckid == NULL) {
 187         ossl_cmp_warn(ctx, "missing Subject Key Identifier in certificate");
 188         return 0;
 189     }
 190     str = i2s_ASN1_OCTET_STRING(NULL, ckid);
 191     if (ASN1_OCTET_STRING_cmp(ckid, skid) == 0) {
 192         if (str != NULL)
 193             ossl_cmp_log1(INFO, ctx, " subjectKID matches senderKID: %s", str);
 194         OPENSSL_free(str);
 195         return 1;
 196     }
 197
 198     if (str != NULL)
 199         ossl_cmp_log1(INFO, ctx, " cert Subject Key Identifier = %s", str);
 200     OPENSSL_free(str);
 201     if ((str = i2s_ASN1_OCTET_STRING(NULL, skid)) != NULL)
 202         ossl_cmp_log1(INFO, ctx, " does not match senderKID    = %s", str);
 203     OPENSSL_free(str);
 204     return 0;
 205 }
 206
 207 static int already_checked(const X509 *cert,
 208                            const STACK_OF(X509) *already_checked)
 209 {
 210     int i;
 211
 212     for (i = sk_X509_num(already_checked /* may be NULL */); i > 0; i--)
 213         if (X509_cmp(sk_X509_value(already_checked, i - 1), cert) == 0)
 214             return 1;
 215     return 0;
 216 }
 217
 218 /*-
 219  * Check if the given cert is acceptable as sender cert of the given message.
 220  * The subject DN must match, the subject key ID as well if present in the msg,
 221  * and the cert must be current (checked if ctx->trusted is not NULL).
 222  * Note that cert revocation etc. is checked by OSSL_CMP_validate_cert_path().
 223  *
 224  * Returns 0 on error or not acceptable, else 1.
 225  */
 226 static int cert_acceptable(const OSSL_CMP_CTX *ctx,
 227                            const char *desc1, const char *desc2, X509 *cert,
 228                            const STACK_OF(X509) *already_checked1,
 229                            const STACK_OF(X509) *already_checked2,
 230                            const OSSL_CMP_MSG *msg)
 231 {
 232     X509_STORE *ts = ctx->trusted;
 233     int self_issued = X509_check_issued(cert, cert) == X509_V_OK;
 234     char *str;
 235     X509_VERIFY_PARAM *vpm = ts != NULL ? X509_STORE_get0_param(ts) : NULL;
 236     int time_cmp;
 237
 238     ossl_cmp_log3(INFO, ctx, " considering %s%s %s with..",
 239                   self_issued ? "self-issued ": "", desc1, desc2);
 240     if ((str = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0)) != NULL)
 241         ossl_cmp_log1(INFO, ctx, "  subject = %s", str);
 242     OPENSSL_free(str);
 243     if (!self_issued) {
 244         str = X509_NAME_oneline(X509_get_issuer_name(cert), NULL, 0);
 245         if (str != NULL)
 246             ossl_cmp_log1(INFO, ctx, "  issuer  = %s", str);
 247         OPENSSL_free(str);
 248     }
 249
 250     if (already_checked(cert, already_checked1)
 251             || already_checked(cert, already_checked2)) {
 252         ossl_cmp_info(ctx, " cert has already been checked");
 253         return 0;
 254     }
 255
 256     time_cmp = X509_cmp_timeframe(vpm, X509_get0_notBefore(cert),
 257                                   X509_get0_notAfter(cert));
 258     if (time_cmp != 0) {
 259         ossl_cmp_warn(ctx, time_cmp > 0 ? "cert has expired"
 260                                         : "cert is not yet valid");
 261         return 0;
 262     }
 263
 264     if (!check_name(ctx, 1,
 265                     "cert subject", X509_get_subject_name(cert),
 266                     "sender field", msg->header->sender->d.directoryName))
 267         return 0;
 268
 269     if (!check_kid(ctx, X509_get0_subject_key_id(cert), msg->header->senderKID))
 270         return 0;
 271     /* prevent misleading error later in case x509v3_cache_extensions() fails */
 272     if (!ossl_x509v3_cache_extensions(cert)) {
 273         ossl_cmp_warn(ctx, "cert appears to be invalid");
 274         return 0;
 275     }
 276     if (!verify_signature(ctx, msg, cert)) {
 277         ossl_cmp_warn(ctx, "msg signature verification failed");
 278         return 0;
 279     }
 280     /* acceptable also if there is no senderKID in msg header */
 281     ossl_cmp_info(ctx, " cert seems acceptable");
 282     return 1;
 283 }
 284
 285 static int check_cert_path(const OSSL_CMP_CTX *ctx, X509_STORE *store,
 286                            X509 *scrt)
 287 {
 288     if (OSSL_CMP_validate_cert_path(ctx, store, scrt))
 289         return 1;
 290
 291     ossl_cmp_warn(ctx,
 292                   "msg signature validates but cert path validation failed");
 293     return 0;
 294 }
 295
 296 /*
 297  * Exceptional handling for 3GPP TS 33.310 [3G/LTE Network Domain Security
 298  * (NDS); Authentication Framework (AF)], only to use for IP messages
 299  * and if the ctx option is explicitly set: use self-issued certificates
 300  * from extraCerts as trust anchor to validate sender cert -
 301  * provided it also can validate the newly enrolled certificate
 302  */
 303 static int check_cert_path_3gpp(const OSSL_CMP_CTX *ctx,
 304                                 const OSSL_CMP_MSG *msg, X509 *scrt)
 305 {
 306     int valid = 0;
 307     X509_STORE *store;
 308
 309     if (!ctx->permitTAInExtraCertsForIR)
 310         return 0;
 311
 312     if ((store = X509_STORE_new()) == NULL
 313             || !ossl_cmp_X509_STORE_add1_certs(store, msg->extraCerts,
 314                                                1 /* self-issued only */))
 315         goto err;
 316
 317     /* store does not include CRLs */
 318     valid = OSSL_CMP_validate_cert_path(ctx, store, scrt);
 319     if (!valid) {
 320         ossl_cmp_warn(ctx,
 321                       "also exceptional 3GPP mode cert path validation failed");
 322     } else {
 323         /*
 324          * verify that the newly enrolled certificate (which assumed rid ==
 325          * OSSL_CMP_CERTREQID) can also be validated with the same trusted store
 326          */
 327         OSSL_CMP_CERTRESPONSE *crep =
 328             ossl_cmp_certrepmessage_get0_certresponse(msg->body->value.ip,
 329                                                       OSSL_CMP_CERTREQID);
 330         X509 *newcrt = ossl_cmp_certresponse_get1_cert(ctx, crep);
 331
 332         /*
 333          * maybe better use get_cert_status() from cmp_client.c, which catches
 334          * errors
 335          */
 336         valid = OSSL_CMP_validate_cert_path(ctx, store, newcrt);
 337         X509_free(newcrt);
 338     }
 339
 340  err:
 341     X509_STORE_free(store);
 342     return valid;
 343 }
 344
 345 static int check_msg_given_cert(const OSSL_CMP_CTX *ctx, X509 *cert,
 346                                 const OSSL_CMP_MSG *msg)
 347 {
 348     return cert_acceptable(ctx, "previously validated", "sender cert",
 349                            cert, NULL, NULL, msg)
 350         && (check_cert_path(ctx, ctx->trusted, cert)
 351             || check_cert_path_3gpp(ctx, msg, cert));
 352 }
 353
 354 /*-
 355  * Try all certs in given list for verifying msg, normally or in 3GPP mode.
 356  * If already_checked1 == NULL then certs are assumed to be the msg->extraCerts.
 357  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
 358  */
 359 static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,
 360                                 const char *desc,
 361                                 const STACK_OF(X509) *already_checked1,
 362                                 const STACK_OF(X509) *already_checked2,
 363                                 const OSSL_CMP_MSG *msg, int mode_3gpp)
 364 {
 365     int in_extraCerts = already_checked1 == NULL;
 366     int n_acceptable_certs = 0;
 367     int i;
 368
 369     if (sk_X509_num(certs) <= 0) {
 370         ossl_cmp_log1(WARN, ctx, "no %s", desc);
 371         return 0;
 372     }
 373
 374     for (i = 0; i < sk_X509_num(certs); i++) { /* certs may be NULL */
 375         X509 *cert = sk_X509_value(certs, i);
 376
 377         if (!ossl_assert(cert != NULL))
 378             return 0;
 379         if (!cert_acceptable(ctx, "cert from", desc, cert,
 380                              already_checked1, already_checked2, msg))
 381             continue;
 382         n_acceptable_certs++;
 383         if (mode_3gpp ? check_cert_path_3gpp(ctx, msg, cert)
 384                       : check_cert_path(ctx, ctx->trusted, cert)) {
 385             /* store successful sender cert for further msgs in transaction */
 386             return ossl_cmp_ctx_set1_validatedSrvCert(ctx, cert);
 387         }
 388     }
 389     if (in_extraCerts && n_acceptable_certs == 0)
 390         ossl_cmp_warn(ctx, "no acceptable cert in extraCerts");
 391     return 0;
 392 }
 393
 394 /*-
 395  * Verify msg trying first ctx->untrusted, which should include extraCerts
 396  * at its front, then trying the trusted certs in truststore (if any) of ctx.
 397  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
 398  */
 399 static int check_msg_all_certs(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 400                                int mode_3gpp)
 401 {
 402     int ret = 0;
 403
 404     if (mode_3gpp
 405             && ((!ctx->permitTAInExtraCertsForIR
 406                      || OSSL_CMP_MSG_get_bodytype(msg) != OSSL_CMP_PKIBODY_IP)))
 407         return 0;
 408
 409     ossl_cmp_info(ctx,
 410                   mode_3gpp ? "normal mode failed; trying now 3GPP mode trusting extraCerts"
 411                             : "trying first normal mode using trust store");
 412     if (check_msg_with_certs(ctx, msg->extraCerts, "extraCerts",
 413                              NULL, NULL, msg, mode_3gpp))
 414         return 1;
 415     if (check_msg_with_certs(ctx, ctx->untrusted, "untrusted certs",
 416                              msg->extraCerts, NULL, msg, mode_3gpp))
 417         return 1;
 418
 419     if (ctx->trusted == NULL) {
 420         ossl_cmp_warn(ctx, mode_3gpp ? "no self-issued extraCerts"
 421                                      : "no trusted store");
 422     } else {
 423         STACK_OF(X509) *trusted = X509_STORE_get1_all_certs(ctx->trusted);
 424
 425         ret = check_msg_with_certs(ctx, trusted,
 426                                    mode_3gpp ? "self-issued extraCerts"
 427                                              : "certs in trusted store",
 428                                    msg->extraCerts, ctx->untrusted,
 429                                    msg, mode_3gpp);
 430         OSSL_STACK_OF_X509_free(trusted);
 431     }
 432     return ret;
 433 }
 434
 435 static int no_log_cb(const char *func, const char *file, int line,
 436                      OSSL_CMP_severity level, const char *msg)
 437 {
 438     return 1;
 439 }
 440
 441 /*-
 442  * Verify message signature with any acceptable and valid candidate cert.
 443  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
 444  */
 445 static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 446 {
 447     X509 *scrt = ctx->validatedSrvCert; /* previous successful sender cert */
 448     GENERAL_NAME *sender = msg->header->sender;
 449     char *sname = NULL;
 450     char *skid_str = NULL;
 451     const ASN1_OCTET_STRING *skid = msg->header->senderKID;
 452     OSSL_CMP_log_cb_t backup_log_cb = ctx->log_cb;
 453     int res = 0;
 454
 455     if (sender == NULL || msg->body == NULL)
 456         return 0; /* other NULL cases already have been checked */
 457     if (sender->type != GEN_DIRNAME) {
 458         /* So far, only X509_NAME is supported */
 459         ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 460         return 0;
 461     }
 462
 463     /* dump any hitherto errors to avoid confusion when printing further ones */
 464     OSSL_CMP_CTX_print_errors(ctx);
 465
 466     /* enable clearing irrelevant errors in attempts to validate sender certs */
 467     (void)ERR_set_mark();
 468     ctx->log_cb = no_log_cb; /* temporarily disable logging */
 469
 470     /*
 471      * try first cached scrt, used successfully earlier in same transaction,
 472      * for validating this and any further msgs where extraCerts may be left out
 473      */
 474     if (scrt != NULL) {
 475         if (check_msg_given_cert(ctx, scrt, msg)) {
 476             ctx->log_cb = backup_log_cb;
 477             (void)ERR_pop_to_mark();
 478             return 1;
 479         }
 480         /* cached sender cert has shown to be no more successfully usable */
 481         (void)ossl_cmp_ctx_set1_validatedSrvCert(ctx, NULL);
 482         /* re-do the above check (just) for adding diagnostic information */
 483         ossl_cmp_info(ctx,
 484                       "trying to verify msg signature with previously validated cert");
 485         (void)check_msg_given_cert(ctx, scrt, msg);
 486     }
 487
 488     res = check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */)
 489             || check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 490     ctx->log_cb = backup_log_cb;
 491     if (res) {
 492         /* discard any diagnostic information on trying to use certs */
 493         (void)ERR_pop_to_mark();
 494         goto end;
 495     }
 496     /* failed finding a sender cert that verifies the message signature */
 497     (void)ERR_clear_last_mark();
 498
 499     sname = X509_NAME_oneline(sender->d.directoryName, NULL, 0);
 500     skid_str = skid == NULL ? NULL : i2s_ASN1_OCTET_STRING(NULL, skid);
 501     if (ctx->log_cb != NULL) {
 502         ossl_cmp_info(ctx, "trying to verify msg signature with a valid cert that..");
 503         if (sname != NULL)
 504             ossl_cmp_log1(INFO, ctx, "matches msg sender    = %s", sname);
 505         if (skid_str != NULL)
 506             ossl_cmp_log1(INFO, ctx, "matches msg senderKID = %s", skid_str);
 507         else
 508             ossl_cmp_info(ctx, "while msg header does not contain senderKID");
 509         /* re-do the above checks (just) for adding diagnostic information */
 510         (void)check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */);
 511         (void)check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 512     }
 513
 514     ERR_raise(ERR_LIB_CMP, CMP_R_NO_SUITABLE_SENDER_CERT);
 515     if (sname != NULL) {
 516         ERR_add_error_txt(NULL, "for msg sender name = ");
 517         ERR_add_error_txt(NULL, sname);
 518     }
 519     if (skid_str != NULL) {
 520         ERR_add_error_txt(" and ", "for msg senderKID = ");
 521         ERR_add_error_txt(NULL, skid_str);
 522     }
 523
 524  end:
 525     OPENSSL_free(sname);
 526     OPENSSL_free(skid_str);
 527     return res;
 528 }
 529
 530 /*-
 531  * Validate the protection of the given PKIMessage using either password-
 532  * based mac (PBM) or a signature algorithm. In the case of signature algorithm,
 533  * the sender certificate can have been pinned by providing it in ctx->srvCert,
 534  * else it is searched in msg->extraCerts, ctx->untrusted, in ctx->trusted
 535  * (in this order) and is path is validated against ctx->trusted.
 536  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
 537  *
 538  * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,
 539  * the trust anchor for validating the IP msg may be taken from msg->extraCerts
 540  * if a self-issued certificate is found there that can be used to
 541  * validate the enrolled certificate returned in the IP.
 542  * This is according to the need given in 3GPP TS 33.310.
 543  *
 544  * Returns 1 on success, 0 on error or validation failed.
 545  */
 546 int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 547 {
 548     X509 *scrt;
 549
 550     ossl_cmp_debug(ctx, "validating CMP message");
 551     if (ctx == NULL || msg == NULL
 552             || msg->header == NULL || msg->body == NULL) {
 553         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
 554         return 0;
 555     }
 556
 557     if (msg->header->protectionAlg == NULL /* unprotected message */
 558             || msg->protection == NULL || msg->protection->data == NULL) {
 559         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);
 560         return 0;
 561     }
 562
 563     switch (ossl_cmp_hdr_get_protection_nid(msg->header)) {
 564         /* 5.1.3.1.  Shared Secret Information */
 565     case NID_id_PasswordBasedMAC:
 566         if (ctx->secretValue == NULL) {
 567             ossl_cmp_info(ctx, "no secret available for verifying PBM-based CMP message protection");
 568             ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_SECRET);
 569             return 0;
 570         }
 571         if (verify_PBMAC(ctx, msg)) {
 572             /*
 573              * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
 574              * "shared secret information", then any certificate transported in
 575              * the caPubs field may be directly trusted as a root CA
 576              * certificate by the initiator.'
 577              */
 578             switch (OSSL_CMP_MSG_get_bodytype(msg)) {
 579             case -1:
 580                 return 0;
 581             case OSSL_CMP_PKIBODY_IP:
 582             case OSSL_CMP_PKIBODY_CP:
 583             case OSSL_CMP_PKIBODY_KUP:
 584             case OSSL_CMP_PKIBODY_CCP:
 585                 if (ctx->trusted != NULL) {
 586                     STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
 587                     /* value.ip is same for cp, kup, and ccp */
 588
 589                     if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
 590                         /* adds both self-issued and not self-issued certs */
 591                         return 0;
 592                 }
 593                 break;
 594             default:
 595                 break;
 596             }
 597             ossl_cmp_debug(ctx,
 598                            "successfully validated PBM-based CMP message protection");
 599             return 1;
 600         }
 601         ossl_cmp_warn(ctx, "verifying PBM-based CMP message protection failed");
 602         break;
 603
 604         /*
 605          * 5.1.3.2 DH Key Pairs
 606          * Not yet supported
 607          */
 608     case NID_id_DHBasedMac:
 609         ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PROTECTION_ALG_DHBASEDMAC);
 610         break;
 611
 612         /*
 613          * 5.1.3.3.  Signature
 614          */
 615     default:
 616         scrt = ctx->srvCert;
 617         if (scrt == NULL) {
 618             if (ctx->trusted == NULL) {
 619                 ossl_cmp_info(ctx, "no trust store nor pinned server cert available for verifying signature-based CMP message protection");
 620                 ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_ANCHOR);
 621                 return 0;
 622             }
 623             if (check_msg_find_cert(ctx, msg)) {
 624                 ossl_cmp_debug(ctx,
 625                                "successfully validated signature-based CMP message protection using trust store");
 626                 return 1;
 627             }
 628         } else { /* use pinned sender cert */
 629             /* use ctx->srvCert for signature check even if not acceptable */
 630             if (verify_signature(ctx, msg, scrt)) {
 631                 ossl_cmp_debug(ctx,
 632                                "successfully validated signature-based CMP message protection using pinned server cert");
 633                 return ossl_cmp_ctx_set1_validatedSrvCert(ctx, scrt);
 634             }
 635             ossl_cmp_warn(ctx, "CMP message signature verification failed");
 636             ERR_raise(ERR_LIB_CMP, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);
 637         }
 638         break;
 639     }
 640     return 0;
 641 }
 642
 643 static int check_transactionID_or_nonce(ASN1_OCTET_STRING *expected,
 644                                         ASN1_OCTET_STRING *actual, int reason)
 645 {
 646     if (expected != NULL
 647         && (actual == NULL || ASN1_OCTET_STRING_cmp(expected, actual) != 0)) {
 648 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 649         char *expected_str, *actual_str;
 650
 651         expected_str = i2s_ASN1_OCTET_STRING(NULL, expected);
 652         actual_str = actual == NULL ? NULL: i2s_ASN1_OCTET_STRING(NULL, actual);
 653         ERR_raise_data(ERR_LIB_CMP, reason,
 654                        "expected = %s, actual = %s",
 655                        expected_str == NULL ? "?" : expected_str,
 656                        actual == NULL ? "(none)" :
 657                        actual_str == NULL ? "?" : actual_str);
 658         OPENSSL_free(expected_str);
 659         OPENSSL_free(actual_str);
 660         return 0;
 661 #endif
 662     }
 663     return 1;
 664 }
 665
 666 /*-
 667  * Check received message (i.e., response by server or request from client)
 668  * Any msg->extraCerts are prepended to ctx->untrusted.
 669  *
 670  * Ensures that:
 671  * its sender is of appropriate type (currently only X509_NAME) and
 672  *     matches any expected sender or srvCert subject given in the ctx
 673  * it has a valid body type
 674  * its protection is valid (or invalid/absent, but only if a callback function
 675  *     is present and yields a positive result using also the supplied argument)
 676  * its transaction ID matches the previous transaction ID stored in ctx (if any)
 677  * its recipNonce matches the previous senderNonce stored in the ctx (if any)
 678  *
 679  * If everything is fine:
 680  * learns the senderNonce from the received message,
 681  * learns the transaction ID if it is not yet in ctx,
 682  * and makes any certs in caPubs directly trusted.
 683  *
 684  * Returns 1 on success, 0 on error.
 685  */
 686 int ossl_cmp_msg_check_update(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 687                               ossl_cmp_allow_unprotected_cb_t cb, int cb_arg)
 688 {
 689     OSSL_CMP_PKIHEADER *hdr;
 690     const X509_NAME *expected_sender;
 691
 692     if (!ossl_assert(ctx != NULL && msg != NULL && msg->header != NULL))
 693         return 0;
 694     hdr = OSSL_CMP_MSG_get0_header(msg);
 695
 696     /* validate sender name of received msg */
 697     if (hdr->sender->type != GEN_DIRNAME) {
 698         ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 699         return 0;
 700     }
 701     /*
 702      * Compare actual sender name of response with expected sender name.
 703      * Mitigates risk to accept misused PBM secret
 704      * or misused certificate of an unauthorized entity of a trusted hierarchy.
 705      */
 706     expected_sender = ctx->expected_sender;
 707     if (expected_sender == NULL && ctx->srvCert != NULL)
 708         expected_sender = X509_get_subject_name(ctx->srvCert);
 709     if (!check_name(ctx, 0, "sender DN field", hdr->sender->d.directoryName,
 710                     "expected sender", expected_sender))
 711         return 0;
 712     /* Note: if recipient was NULL-DN it could be learned here if needed */
 713
 714     if (sk_X509_num(msg->extraCerts) > 10)
 715         ossl_cmp_warn(ctx,
 716                       "received CMP message contains more than 10 extraCerts");
 717     /*
 718      * Store any provided extraCerts in ctx for use in OSSL_CMP_validate_msg()
 719      * and for future use, such that they are available to ctx->certConf_cb and
 720      * the peer does not need to send them again in the same transaction.
 721      * Note that it does not help validating the message before storing the
 722      * extraCerts because they do not belong to the protected msg part anyway.
 723      * For efficiency, the extraCerts are prepended so they get used first.
 724      */
 725     if (!X509_add_certs(ctx->untrusted, msg->extraCerts,
 726                         /* this allows self-signed certs */
 727                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 728                         | X509_ADD_FLAG_PREPEND))
 729         return 0;
 730
 731     /* validate message protection */
 732     if (hdr->protectionAlg != NULL) {
 733         /* detect explicitly permitted exceptions for invalid protection */
 734         if (!OSSL_CMP_validate_msg(ctx, msg)
 735                 && (cb == NULL || (*cb)(ctx, msg, 1, cb_arg) <= 0)) {
 736 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 737             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_PROTECTION);
 738             return 0;
 739 #endif
 740         }
 741     } else {
 742         /* detect explicitly permitted exceptions for missing protection */
 743         if (cb == NULL || (*cb)(ctx, msg, 0, cb_arg) <= 0) {
 744 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 745             ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);
 746             return 0;
 747 #endif
 748         }
 749     }
 750
 751     /* check CMP version number in header */
 752     if (ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO_2
 753             && ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO_3) {
 754 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 755         ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PVNO);
 756         return 0;
 757 #endif
 758     }
 759
 760     if (OSSL_CMP_MSG_get_bodytype(msg) < 0) {
 761 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 762         ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);
 763         return 0;
 764 #endif
 765     }
 766
 767     /* compare received transactionID with the expected one in previous msg */
 768     if (!check_transactionID_or_nonce(ctx->transactionID, hdr->transactionID,
 769                                       CMP_R_TRANSACTIONID_UNMATCHED))
 770         return 0;
 771
 772     /* compare received nonce with the one we sent */
 773     if (!check_transactionID_or_nonce(ctx->senderNonce, hdr->recipNonce,
 774                                       CMP_R_RECIPNONCE_UNMATCHED))
 775         return 0;
 776
 777     /* if not yet present, learn transactionID */
 778     if (ctx->transactionID == NULL
 779         && !OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID))
 780         return 0;
 781
 782     /*
 783      * RFC 4210 section 5.1.1 states: the recipNonce is copied from
 784      * the senderNonce of the previous message in the transaction.
 785      * --> Store for setting in next message
 786      */
 787     if (!ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce))
 788         return 0;
 789
 790     /*
 791      * Store any provided extraCerts in ctx for future use,
 792      * such that they are available to ctx->certConf_cb and
 793      * the peer does not need to send them again in the same transaction.
 794      * For efficiency, the extraCerts are prepended so they get used first.
 795      */
 796     if (!X509_add_certs(ctx->untrusted, msg->extraCerts,
 797                         /* this allows self-signed certs */
 798                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 799                         | X509_ADD_FLAG_PREPEND))
 800         return 0;
 801
 802     if (ossl_cmp_hdr_get_protection_nid(hdr) == NID_id_PasswordBasedMAC) {
 803         /*
 804          * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
 805          * "shared secret information", then any certificate transported in
 806          * the caPubs field may be directly trusted as a root CA
 807          * certificate by the initiator.'
 808          */
 809         switch (OSSL_CMP_MSG_get_bodytype(msg)) {
 810         case OSSL_CMP_PKIBODY_IP:
 811         case OSSL_CMP_PKIBODY_CP:
 812         case OSSL_CMP_PKIBODY_KUP:
 813         case OSSL_CMP_PKIBODY_CCP:
 814             if (ctx->trusted != NULL) {
 815                 STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
 816                 /* value.ip is same for cp, kup, and ccp */
 817
 818                 if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
 819                     /* adds both self-issued and not self-issued certs */
 820                     return 0;
 821             }
 822             break;
 823         default:
 824             break;
 825         }
 826     }
 827     return 1;
 828 }
 829
 830 int ossl_cmp_verify_popo(const OSSL_CMP_CTX *ctx,
 831                          const OSSL_CMP_MSG *msg, int acceptRAVerified)
 832 {
 833     if (!ossl_assert(msg != NULL && msg->body != NULL))
 834         return 0;
 835     switch (msg->body->type) {
 836     case OSSL_CMP_PKIBODY_P10CR:
 837         {
 838             X509_REQ *req = msg->body->value.p10cr;
 839
 840             if (X509_REQ_verify_ex(req, X509_REQ_get0_pubkey(req), ctx->libctx,
 841                                    ctx->propq) <= 0) {
 842 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 843                 ERR_raise(ERR_LIB_CMP, CMP_R_REQUEST_NOT_ACCEPTED);
 844                 return 0;
 845 #endif
 846             }
 847         }
 848         break;
 849     case OSSL_CMP_PKIBODY_IR:
 850     case OSSL_CMP_PKIBODY_CR:
 851     case OSSL_CMP_PKIBODY_KUR:
 852         if (!OSSL_CRMF_MSGS_verify_popo(msg->body->value.ir, OSSL_CMP_CERTREQID,
 853                                         acceptRAVerified,
 854                                         ctx->libctx, ctx->propq)) {
 855 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 856             return 0;
 857 #endif
 858         }
 859         break;
 860     default:
 861         ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);
 862         return 0;
 863     }
 864     return 1;
 865 }