crypto/cmp/cmp_vfy.c

   1 /*
   2  * Copyright 2007-2020 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 #include "crypto/x509.h"
  24
  25 DEFINE_STACK_OF(X509)
  26
  27 /* Verify a message protected by signature according to RFC section 5.1.3.3 */
  28 static int verify_signature(const OSSL_CMP_CTX *cmp_ctx,
  29                             const OSSL_CMP_MSG *msg, X509 *cert)
  30 {
  31     OSSL_CMP_PROTECTEDPART prot_part;
  32     EVP_PKEY *pubkey = NULL;
  33     BIO *bio = BIO_new(BIO_s_mem()); /* may be NULL */
  34     int res = 0;
  35
  36     if (!ossl_assert(cmp_ctx != NULL && msg != NULL && cert != NULL))
  37         return 0;
  38
  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         CMPerr(0, CMP_R_MISSING_KEY_USAGE_DIGITALSIGNATURE);
  43         goto sig_err;
  44     }
  45
  46     pubkey = X509_get_pubkey(cert);
  47     if (pubkey == NULL) {
  48         CMPerr(0, 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_with_libctx(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART),
  56                                      msg->header->protectionAlg,
  57                                      msg->protection, &prot_part, NULL, pubkey,
  58                                      cmp_ctx->libctx, cmp_ctx->propq) > 0) {
  59         res = 1;
  60         goto end;
  61     }
  62
  63  sig_err:
  64     res = x509_print_ex_brief(bio, cert, X509_FLAG_NO_EXTENSIONS);
  65     CMPerr(0, 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         CMPerr(0, 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         CMPerr(0, CMP_R_NULL_ARGUMENT);
 115         return 0;
 116     }
 117
 118     if (trusted_store == NULL) {
 119         CMPerr(0, CMP_R_MISSING_TRUST_STORE);
 120         return 0;
 121     }
 122
 123     if ((csc = X509_STORE_CTX_new_with_libctx(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         CMPerr(0, 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 = OPENSSL_buf2hexstr(ckid->data, ckid->length);
 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 = OPENSSL_buf2hexstr(skid->data, skid->length)) != 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 (!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         EVP_PKEY *pkey = OSSL_CMP_CTX_get0_newPkey(ctx, 1);
 328         OSSL_CMP_CERTRESPONSE *crep =
 329             ossl_cmp_certrepmessage_get0_certresponse(msg->body->value.ip,
 330                                                       OSSL_CMP_CERTREQID);
 331         X509 *newcrt = ossl_cmp_certresponse_get1_cert(crep, ctx, pkey);
 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_set0_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             if (!X509_up_ref(cert))
 387                 return 0;
 388             if (!ossl_cmp_ctx_set0_validatedSrvCert(ctx, cert)) {
 389                 X509_free(cert);
 390                 return 0;
 391             }
 392             return 1;
 393         }
 394     }
 395     if (in_extraCerts && n_acceptable_certs == 0)
 396         ossl_cmp_warn(ctx, "no acceptable cert in extraCerts");
 397     return 0;
 398 }
 399
 400 /*-
 401  * Verify msg trying first ctx->untrusted, which should include extraCerts
 402  * at its front, then trying the trusted certs in truststore (if any) of ctx.
 403  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 404  */
 405 static int check_msg_all_certs(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 406                                int mode_3gpp)
 407 {
 408     int ret = 0;
 409
 410     if (mode_3gpp
 411             && ((!ctx->permitTAInExtraCertsForIR
 412                      || ossl_cmp_msg_get_bodytype(msg) != OSSL_CMP_PKIBODY_IP)))
 413         return 0;
 414
 415     ossl_cmp_info(ctx,
 416                   mode_3gpp ? "normal mode failed; trying now 3GPP mode trusting extraCerts"
 417                             : "trying first normal mode using trust store");
 418     if (check_msg_with_certs(ctx, msg->extraCerts, "extraCerts",
 419                              NULL, NULL, msg, mode_3gpp))
 420         return 1;
 421     if (check_msg_with_certs(ctx, ctx->untrusted, "untrusted certs",
 422                              msg->extraCerts, NULL, msg, mode_3gpp))
 423         return 1;
 424
 425     if (ctx->trusted == NULL) {
 426         ossl_cmp_warn(ctx, mode_3gpp ? "no self-issued extraCerts"
 427                                      : "no trusted store");
 428     } else {
 429         STACK_OF(X509) *trusted = X509_STORE_get1_all_certs(ctx->trusted);
 430         ret = check_msg_with_certs(ctx, trusted,
 431                                    mode_3gpp ? "self-issued extraCerts"
 432                                              : "certs in trusted store",
 433                                    msg->extraCerts, ctx->untrusted,
 434                                    msg, mode_3gpp);
 435         sk_X509_pop_free(trusted, X509_free);
 436     }
 437     return ret;
 438 }
 439
 440 static int no_log_cb(const char *func, const char *file, int line,
 441                      OSSL_CMP_severity level, const char *msg)
 442 {
 443     return 1;
 444 }
 445
 446 /*-
 447  * Verify message signature with any acceptable and valid candidate cert.
 448  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 449  */
 450 static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 451 {
 452     X509 *scrt = ctx->validatedSrvCert; /* previous successful sender cert */
 453     GENERAL_NAME *sender = msg->header->sender;
 454     char *sname = NULL;
 455     char *skid_str = NULL;
 456     const ASN1_OCTET_STRING *skid = msg->header->senderKID;
 457     OSSL_CMP_log_cb_t backup_log_cb = ctx->log_cb;
 458     int res = 0;
 459
 460     if (sender == NULL || msg->body == NULL)
 461         return 0; /* other NULL cases already have been checked */
 462     if (sender->type != GEN_DIRNAME) {
 463         CMPerr(0, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 464         return 0;
 465     }
 466
 467     /* dump any hitherto errors to avoid confusion when printing further ones */
 468     OSSL_CMP_CTX_print_errors(ctx);
 469
 470     /* enable clearing irrelevant errors in attempts to validate sender certs */
 471     (void)ERR_set_mark();
 472     ctx->log_cb = no_log_cb; /* temporarily disable logging */
 473
 474     /*
 475      * try first cached scrt, used successfully earlier in same transaction,
 476      * for validating this and any further msgs where extraCerts may be left out
 477      */
 478     if (scrt != NULL) {
 479         if (check_msg_given_cert(ctx, scrt, msg)) {
 480             ctx->log_cb = backup_log_cb;
 481             (void)ERR_pop_to_mark();
 482             return 1;
 483         }
 484         /* cached sender cert has shown to be no more successfully usable */
 485         (void)ossl_cmp_ctx_set0_validatedSrvCert(ctx, NULL);
 486         /* re-do the above check (just) for adding diagnostic information */
 487         ossl_cmp_info(ctx,
 488                       "trying to verify msg signature with previously validated cert");
 489         (void)check_msg_given_cert(ctx, scrt, msg);
 490     }
 491
 492     res = check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */)
 493             || check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 494     ctx->log_cb = backup_log_cb;
 495     if (res) {
 496         /* discard any diagnostic information on trying to use certs */
 497         (void)ERR_pop_to_mark();
 498         goto end;
 499     }
 500     /* failed finding a sender cert that verifies the message signature */
 501     (void)ERR_clear_last_mark();
 502
 503     sname = X509_NAME_oneline(sender->d.directoryName, NULL, 0);
 504     skid_str = skid == NULL ? NULL
 505                             : OPENSSL_buf2hexstr(skid->data, skid->length);
 506     if (ctx->log_cb != NULL) {
 507         ossl_cmp_info(ctx, "trying to verify msg signature with a valid cert that..");
 508         if (sname != NULL)
 509             ossl_cmp_log1(INFO, ctx, "matches msg sender    = %s", sname);
 510         if (skid_str != NULL)
 511             ossl_cmp_log1(INFO, ctx, "matches msg senderKID = %s", skid_str);
 512         else
 513             ossl_cmp_info(ctx, "while msg header does not contain senderKID");
 514         /* re-do the above checks (just) for adding diagnostic information */
 515         (void)check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */);
 516         (void)check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 517     }
 518
 519     CMPerr(0, CMP_R_NO_SUITABLE_SENDER_CERT);
 520     if (sname != NULL) {
 521         ERR_add_error_txt(NULL, "for msg sender name = ");
 522         ERR_add_error_txt(NULL, sname);
 523     }
 524     if (skid_str != NULL) {
 525         ERR_add_error_txt(" and ", "for msg senderKID = ");
 526         ERR_add_error_txt(NULL, skid_str);
 527     }
 528
 529  end:
 530     OPENSSL_free(sname);
 531     OPENSSL_free(skid_str);
 532     return res;
 533 }
 534
 535 /*-
 536  * Validate the protection of the given PKIMessage using either password-
 537  * based mac (PBM) or a signature algorithm. In the case of signature algorithm,
 538  * the sender certificate can have been pinned by providing it in ctx->srvCert,
 539  * else it is searched in msg->extraCerts, ctx->untrusted, in ctx->trusted
 540  * (in this order) and is path is validated against ctx->trusted.
 541  * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().
 542  *
 543  * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,
 544  * the trust anchor for validating the IP msg may be taken from msg->extraCerts
 545  * if a self-issued certificate is found there that can be used to
 546  * validate the enrolled certificate returned in the IP.
 547  * This is according to the need given in 3GPP TS 33.310.
 548  *
 549  * Returns 1 on success, 0 on error or validation failed.
 550  */
 551 int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 552 {
 553     X509 *scrt;
 554
 555     ossl_cmp_debug(ctx, "validating CMP message");
 556     if (ctx == NULL || msg == NULL
 557             || msg->header == NULL || msg->body == NULL) {
 558         CMPerr(0, CMP_R_NULL_ARGUMENT);
 559         return 0;
 560     }
 561
 562     if (msg->header->protectionAlg == NULL /* unprotected message */
 563             || msg->protection == NULL || msg->protection->data == NULL) {
 564         CMPerr(0, CMP_R_MISSING_PROTECTION);
 565         return 0;
 566     }
 567
 568     switch (ossl_cmp_hdr_get_protection_nid(msg->header)) {
 569         /* 5.1.3.1.  Shared Secret Information */
 570     case NID_id_PasswordBasedMAC:
 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                            "sucessfully 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         CMPerr(0, 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 (check_msg_find_cert(ctx, msg))
 619                 return 1;
 620         } else { /* use pinned sender cert */
 621             /* use ctx->srvCert for signature check even if not acceptable */
 622             if (verify_signature(ctx, msg, scrt)) {
 623                 ossl_cmp_debug(ctx,
 624                                "sucessfully validated signature-based CMP message protection");
 625
 626                 return 1;
 627             }
 628             ossl_cmp_warn(ctx, "CMP message signature verification failed");
 629             CMPerr(0, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);
 630         }
 631         break;
 632     }
 633     return 0;
 634 }
 635
 636
 637 /*-
 638  * Check received message (i.e., response by server or request from client)
 639  * Any msg->extraCerts are prepended to ctx->untrusted.
 640  *
 641  * Ensures that:
 642  * its sender is of appropriate type (curently only X509_NAME) and
 643  *     matches any expected sender or srvCert subject given in the ctx
 644  * it has a valid body type
 645  * its protection is valid (or invalid/absent, but only if a callback function
 646  *     is present and yields a positive result using also the supplied argument)
 647  * its transaction ID matches the previous transaction ID stored in ctx (if any)
 648  * its recipNonce matches the previous senderNonce stored in the ctx (if any)
 649  *
 650  * If everything is fine:
 651  * learns the senderNonce from the received message,
 652  * learns the transaction ID if it is not yet in ctx,
 653  * and makes any certs in caPubs directly trusted.
 654  *
 655  * Returns 1 on success, 0 on error.
 656  */
 657 int ossl_cmp_msg_check_update(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 658                               ossl_cmp_allow_unprotected_cb_t cb, int cb_arg)
 659 {
 660     OSSL_CMP_PKIHEADER *hdr;
 661     const X509_NAME *expected_sender;
 662
 663     if (!ossl_assert(ctx != NULL && msg != NULL && msg->header != NULL))
 664         return 0;
 665     hdr = OSSL_CMP_MSG_get0_header(msg);
 666
 667     /* validate sender name of received msg */
 668     if (hdr->sender->type != GEN_DIRNAME) {
 669         CMPerr(0, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 670         return 0; /* TODO FR#42: support for more than X509_NAME */
 671     }
 672     /*
 673      * Compare actual sender name of response with expected sender name.
 674      * Mitigates risk to accept misused PBM secret
 675      * or misused certificate of an unauthorized entity of a trusted hierarchy.
 676      */
 677     expected_sender = ctx->expected_sender;
 678     if (expected_sender == NULL && ctx->srvCert != NULL)
 679         expected_sender = X509_get_subject_name(ctx->srvCert);
 680     if (!check_name(ctx, 0, "sender DN field", hdr->sender->d.directoryName,
 681                     "expected sender", expected_sender))
 682         return 0;
 683     /* Note: if recipient was NULL-DN it could be learned here if needed */
 684
 685     if (sk_X509_num(msg->extraCerts) > 10)
 686         ossl_cmp_warn(ctx,
 687                       "received CMP message contains more than 10 extraCerts");
 688     /*
 689      * Store any provided extraCerts in ctx for use in OSSL_CMP_validate_msg()
 690      * and for future use, such that they are available to ctx->certConf_cb and
 691      * the peer does not need to send them again in the same transaction.
 692      * Note that it does not help validating the message before storing the
 693      * extraCerts because they do not belong to the protected msg part anyway.
 694      * For efficiency, the extraCerts are prepended so they get used first.
 695      */
 696     if (!X509_add_certs(ctx->untrusted, msg->extraCerts,
 697                         /* this allows self-signed certs */
 698                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 699                         | X509_ADD_FLAG_PREPEND))
 700         return 0;
 701
 702     /* validate message protection */
 703     if (hdr->protectionAlg != NULL) {
 704         /* detect explicitly permitted exceptions for invalid protection */
 705         if (!OSSL_CMP_validate_msg(ctx, msg)
 706                 && (cb == NULL || (*cb)(ctx, msg, 1, cb_arg) <= 0)) {
 707 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 708             CMPerr(0, CMP_R_ERROR_VALIDATING_PROTECTION);
 709             return 0;
 710 #endif
 711         }
 712     } else {
 713         /* detect explicitly permitted exceptions for missing protection */
 714         if (cb == NULL || (*cb)(ctx, msg, 0, cb_arg) <= 0) {
 715 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 716             CMPerr(0, CMP_R_MISSING_PROTECTION);
 717             return 0;
 718 #endif
 719         }
 720     }
 721
 722     /* check CMP version number in header */
 723     if (ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO) {
 724 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 725         CMPerr(0, CMP_R_UNEXPECTED_PVNO);
 726         return 0;
 727 #endif
 728     }
 729
 730     if (ossl_cmp_msg_get_bodytype(msg) < 0) {
 731 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 732         CMPerr(0, CMP_R_PKIBODY_ERROR);
 733         return 0;
 734 #endif
 735     }
 736
 737     /* compare received transactionID with the expected one in previous msg */
 738     if (ctx->transactionID != NULL
 739             && (hdr->transactionID == NULL
 740                 || ASN1_OCTET_STRING_cmp(ctx->transactionID,
 741                                          hdr->transactionID) != 0)) {
 742 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 743         CMPerr(0, CMP_R_TRANSACTIONID_UNMATCHED);
 744         return 0;
 745 #endif
 746     }
 747
 748     /* compare received nonce with the one we sent */
 749     if (ctx->senderNonce != NULL
 750             && (msg->header->recipNonce == NULL
 751                 || ASN1_OCTET_STRING_cmp(ctx->senderNonce,
 752                                          hdr->recipNonce) != 0)) {
 753 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 754         CMPerr(0, CMP_R_RECIPNONCE_UNMATCHED);
 755         return 0;
 756 #endif
 757     }
 758
 759     /*
 760      * RFC 4210 section 5.1.1 states: the recipNonce is copied from
 761      * the senderNonce of the previous message in the transaction.
 762      * --> Store for setting in next message
 763      */
 764     if (!ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce))
 765         return 0;
 766
 767     /* if not yet present, learn transactionID */
 768     if (ctx->transactionID == NULL
 769         && !OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID))
 770         return -1;
 771
 772     /*
 773      * Store any provided extraCerts in ctx for future use,
 774      * such that they are available to ctx->certConf_cb and
 775      * the peer does not need to send them again in the same transaction.
 776      * For efficiency, the extraCerts are prepended so they get used first.
 777      */
 778     if (!X509_add_certs(ctx->untrusted, msg->extraCerts,
 779                         /* this allows self-signed certs */
 780                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 781                         | X509_ADD_FLAG_PREPEND))
 782         return -1;
 783
 784     if (ossl_cmp_hdr_get_protection_nid(hdr) == NID_id_PasswordBasedMAC) {
 785         /*
 786          * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
 787          * "shared secret information", then any certificate transported in
 788          * the caPubs field may be directly trusted as a root CA
 789          * certificate by the initiator.'
 790          */
 791         switch (ossl_cmp_msg_get_bodytype(msg)) {
 792         case OSSL_CMP_PKIBODY_IP:
 793         case OSSL_CMP_PKIBODY_CP:
 794         case OSSL_CMP_PKIBODY_KUP:
 795         case OSSL_CMP_PKIBODY_CCP:
 796             if (ctx->trusted != NULL) {
 797                 STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
 798                 /* value.ip is same for cp, kup, and ccp */
 799
 800                 if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
 801                     /* adds both self-issued and not self-issued certs */
 802                     return 0;
 803             }
 804             break;
 805         default:
 806             break;
 807         }
 808     }
 809     return 1;
 810 }
 811
 812 int ossl_cmp_verify_popo(const OSSL_CMP_CTX *ctx,
 813                          const OSSL_CMP_MSG *msg, int acceptRAVerified)
 814 {
 815     if (!ossl_assert(msg != NULL && msg->body != NULL))
 816         return 0;
 817     switch (msg->body->type) {
 818     case OSSL_CMP_PKIBODY_P10CR:
 819         {
 820             X509_REQ *req = msg->body->value.p10cr;
 821
 822             if (X509_REQ_verify_with_libctx(req, X509_REQ_get0_pubkey(req),
 823                                             ctx->libctx, ctx->propq) <= 0) {
 824 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 825                 CMPerr(0, CMP_R_REQUEST_NOT_ACCEPTED);
 826                 return 0;
 827 #endif
 828             }
 829         }
 830         break;
 831     case OSSL_CMP_PKIBODY_IR:
 832     case OSSL_CMP_PKIBODY_CR:
 833     case OSSL_CMP_PKIBODY_KUR:
 834         if (!OSSL_CRMF_MSGS_verify_popo(msg->body->value.ir, OSSL_CMP_CERTREQID,
 835                                         acceptRAVerified,
 836                                         ctx->libctx, ctx->propq)) {
 837 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 838             return 0;
 839 #endif
 840         }
 841         break;
 842     default:
 843         CMPerr(0, CMP_R_PKIBODY_ERROR);
 844         return 0;
 845     }
 846     return 1;
 847 }