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 /*
  28  * Verify a message protected by signature according to section 5.1.3.3
  29  * (sha1+RSA/DSA or any other algorithm supported by OpenSSL).
  30  *
  31  * Returns 1 on successful validation and 0 otherwise.
  32  */
  33 static int verify_signature(const OSSL_CMP_CTX *cmp_ctx,
  34                             const OSSL_CMP_MSG *msg, X509 *cert)
  35 {
  36     EVP_MD_CTX *ctx = NULL;
  37     OSSL_CMP_PROTECTEDPART prot_part;
  38     int digest_nid, pk_nid;
  39     const EVP_MD *digest = NULL;
  40     EVP_PKEY *pubkey = NULL;
  41     int len;
  42     size_t prot_part_der_len = 0;
  43     unsigned char *prot_part_der = NULL;
  44     BIO *bio = BIO_new(BIO_s_mem()); /* may be NULL */
  45     int res = 0;
  46
  47     if (!ossl_assert(cmp_ctx != NULL && msg != NULL && cert != NULL))
  48         return 0;
  49
  50     /* verify that keyUsage, if present, contains digitalSignature */
  51     if (!cmp_ctx->ignore_keyusage
  52             && (X509_get_key_usage(cert) & X509v3_KU_DIGITAL_SIGNATURE) == 0) {
  53         CMPerr(0, CMP_R_MISSING_KEY_USAGE_DIGITALSIGNATURE);
  54         goto sig_err;
  55     }
  56
  57     pubkey = X509_get_pubkey(cert);
  58     if (pubkey == NULL) {
  59         CMPerr(0, CMP_R_FAILED_EXTRACTING_PUBKEY);
  60         goto sig_err;
  61     }
  62
  63     /* create the DER representation of protected part */
  64     prot_part.header = msg->header;
  65     prot_part.body = msg->body;
  66
  67     len = i2d_OSSL_CMP_PROTECTEDPART(&prot_part, &prot_part_der);
  68     if (len < 0 || prot_part_der == NULL)
  69         goto end;
  70     prot_part_der_len = (size_t) len;
  71
  72     /* verify signature of protected part */
  73     if (!OBJ_find_sigid_algs(OBJ_obj2nid(msg->header->protectionAlg->algorithm),
  74                              &digest_nid, &pk_nid)
  75             || digest_nid == NID_undef || pk_nid == NID_undef
  76             || (digest = EVP_get_digestbynid(digest_nid)) == NULL) {
  77         CMPerr(0, CMP_R_ALGORITHM_NOT_SUPPORTED);
  78         goto sig_err;
  79     }
  80
  81     /* check msg->header->protectionAlg is consistent with public key type */
  82     if (EVP_PKEY_type(pk_nid) != EVP_PKEY_base_id(pubkey)) {
  83         CMPerr(0, CMP_R_WRONG_ALGORITHM_OID);
  84         goto sig_err;
  85     }
  86     if ((ctx = EVP_MD_CTX_new()) == NULL)
  87         goto end;
  88     if (EVP_DigestVerifyInit(ctx, NULL, digest, NULL, pubkey)
  89             && EVP_DigestVerify(ctx, msg->protection->data,
  90                                 msg->protection->length,
  91                                 prot_part_der, prot_part_der_len) == 1) {
  92         res = 1;
  93         goto end;
  94     }
  95
  96  sig_err:
  97     res = x509_print_ex_brief(bio, cert, X509_FLAG_NO_EXTENSIONS);
  98     CMPerr(0, CMP_R_ERROR_VALIDATING_SIGNATURE);
  99     if (res)
 100         ERR_add_error_mem_bio("\n", bio);
 101     res = 0;
 102
 103  end:
 104     EVP_MD_CTX_free(ctx);
 105     OPENSSL_free(prot_part_der);
 106     EVP_PKEY_free(pubkey);
 107     BIO_free(bio);
 108
 109     return res;
 110 }
 111
 112 /* Verify a message protected with PBMAC */
 113 static int verify_PBMAC(const OSSL_CMP_MSG *msg,
 114                         const ASN1_OCTET_STRING *secret)
 115 {
 116     ASN1_BIT_STRING *protection = NULL;
 117     int valid = 0;
 118
 119     /* generate expected protection for the message */
 120     if ((protection = ossl_cmp_calc_protection(msg, secret, NULL)) == NULL)
 121         return 0; /* failed to generate protection string! */
 122
 123     valid = msg->protection != NULL && msg->protection->length >= 0
 124             && msg->protection->type == protection->type
 125             && msg->protection->length == protection->length
 126             && CRYPTO_memcmp(msg->protection->data, protection->data,
 127                              protection->length) == 0;
 128     ASN1_BIT_STRING_free(protection);
 129     if (!valid)
 130         CMPerr(0, CMP_R_WRONG_PBM_VALUE);
 131
 132     return valid;
 133 }
 134
 135 /*
 136  * Attempt to validate certificate and path using any given store with trusted
 137  * certs (possibly including CRLs and a cert verification callback function)
 138  * and non-trusted intermediate certs from the given ctx.
 139  *
 140  * Returns 1 on successful validation and 0 otherwise.
 141  */
 142 int OSSL_CMP_validate_cert_path(OSSL_CMP_CTX *ctx, X509_STORE *trusted_store,
 143                                 X509 *cert)
 144 {
 145     int valid = 0;
 146     X509_STORE_CTX *csc = NULL;
 147     int err;
 148
 149     if (ctx == NULL || cert == NULL) {
 150         CMPerr(0, CMP_R_NULL_ARGUMENT);
 151         return 0;
 152     }
 153
 154     if (trusted_store == NULL) {
 155         CMPerr(0, CMP_R_MISSING_TRUST_STORE);
 156         return 0;
 157     }
 158
 159     if ((csc = X509_STORE_CTX_new()) == NULL
 160             || !X509_STORE_CTX_init(csc, trusted_store,
 161                                     cert, ctx->untrusted_certs))
 162         goto err;
 163
 164     valid = X509_verify_cert(csc) > 0;
 165
 166     /* make sure suitable error is queued even if callback did not do */
 167     err = ERR_peek_last_error();
 168     if (!valid && ERR_GET_REASON(err) != CMP_R_POTENTIALLY_INVALID_CERTIFICATE)
 169         CMPerr(0, CMP_R_POTENTIALLY_INVALID_CERTIFICATE);
 170
 171  err:
 172     /* directly output any fresh errors, needed for check_msg_find_cert() */
 173     OSSL_CMP_CTX_print_errors(ctx);
 174     X509_STORE_CTX_free(csc);
 175     return valid;
 176 }
 177
 178 /* Return 0 if expect_name != NULL and there is no matching actual_name */
 179 static int check_name(OSSL_CMP_CTX *ctx,
 180                       const char *actual_desc, const X509_NAME *actual_name,
 181                       const char *expect_desc, const X509_NAME *expect_name)
 182 {
 183     char *str;
 184
 185     if (expect_name == NULL)
 186         return 1; /* no expectation, thus trivially fulfilled */
 187
 188     /* make sure that a matching name is there */
 189     if (actual_name == NULL) {
 190         ossl_cmp_log1(WARN, ctx, "missing %s", actual_desc);
 191         return 0;
 192     }
 193     if (X509_NAME_cmp(actual_name, expect_name) == 0)
 194         return 1;
 195
 196     if ((str = X509_NAME_oneline(actual_name, NULL, 0)) != NULL)
 197         ossl_cmp_log2(INFO, ctx, " actual name in %s = %s", actual_desc, str);
 198     OPENSSL_free(str);
 199     if ((str = X509_NAME_oneline(expect_name, NULL, 0)) != NULL)
 200         ossl_cmp_log2(INFO, ctx, " does not match %s = %s", expect_desc, str);
 201     OPENSSL_free(str);
 202     return 0;
 203 }
 204
 205 /* Return 0 if skid != NULL and there is no matching subject key ID in cert */
 206 static int check_kid(OSSL_CMP_CTX *ctx,
 207                      X509 *cert, const ASN1_OCTET_STRING *skid)
 208 {
 209     char *actual, *expect;
 210     const ASN1_OCTET_STRING *ckid = X509_get0_subject_key_id(cert);
 211
 212     if (skid == NULL)
 213         return 1; /* no expectation, thus trivially fulfilled */
 214
 215     /* make sure that the expected subject key identifier is there */
 216     if (ckid == NULL) {
 217         ossl_cmp_warn(ctx, "missing Subject Key Identifier in certificate");
 218         return 0;
 219     }
 220     if (ASN1_OCTET_STRING_cmp(ckid, skid) == 0)
 221         return 1;
 222
 223     if ((actual = OPENSSL_buf2hexstr(ckid->data, ckid->length)) != NULL)
 224         ossl_cmp_log1(INFO, ctx, " cert Subject Key Identifier = %s", actual);
 225     if ((expect = OPENSSL_buf2hexstr(skid->data, skid->length)) != NULL)
 226         ossl_cmp_log1(INFO, ctx, " does not match senderKID    = %s", expect);
 227     OPENSSL_free(expect);
 228     OPENSSL_free(actual);
 229     return 0;
 230 }
 231
 232 static int already_checked(X509 *cert, const STACK_OF(X509) *already_checked)
 233 {
 234     int i;
 235
 236     for (i = sk_X509_num(already_checked /* may be NULL */); i > 0; i--)
 237         if (X509_cmp(sk_X509_value(already_checked, i - 1), cert) == 0)
 238             return 1;
 239     return 0;
 240 }
 241
 242 /*
 243  * Check if the given cert is acceptable as sender cert of the given message.
 244  * The subject DN must match, the subject key ID as well if present in the msg,
 245  * and the cert must be current (checked if ctx->trusted is not NULL).
 246  * Note that cert revocation etc. is checked by OSSL_CMP_validate_cert_path().
 247  *
 248  * Returns 0 on error or not acceptable, else 1.
 249  */
 250 static int cert_acceptable(OSSL_CMP_CTX *ctx,
 251                            const char *desc1, const char *desc2, X509 *cert,
 252                            const STACK_OF(X509) *already_checked1,
 253                            const STACK_OF(X509) *already_checked2,
 254                            const OSSL_CMP_MSG *msg)
 255 {
 256     X509_STORE *ts = ctx->trusted;
 257     int self_issued = X509_check_issued(cert, cert) == X509_V_OK;
 258     char *str;
 259     X509_VERIFY_PARAM *vpm = ts != NULL ? X509_STORE_get0_param(ts) : NULL;
 260     int time_cmp;
 261
 262     ossl_cmp_log3(INFO, ctx, " considering %s%s %s with..",
 263                   self_issued ? "self-issued ": "", desc1, desc2);
 264     if ((str = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0)) != NULL)
 265         ossl_cmp_log1(INFO, ctx, "  subject = %s", str);
 266     OPENSSL_free(str);
 267     if (!self_issued) {
 268         str = X509_NAME_oneline(X509_get_issuer_name(cert), NULL, 0);
 269         if (str != NULL)
 270             ossl_cmp_log1(INFO, ctx, "  issuer  = %s", str);
 271         OPENSSL_free(str);
 272     }
 273
 274     if (already_checked(cert, already_checked1)
 275             || already_checked(cert, already_checked2)) {
 276         ossl_cmp_info(ctx, " cert has already been checked");
 277         return 0;
 278     }
 279
 280     time_cmp = X509_cmp_timeframe(vpm, X509_get0_notBefore(cert),
 281                                   X509_get0_notAfter(cert));
 282     if (time_cmp != 0) {
 283         ossl_cmp_warn(ctx, time_cmp > 0 ? "cert has expired"
 284                                         : "cert is not yet valid");
 285         return 0;
 286     }
 287
 288     if (!check_name(ctx,
 289                     "cert subject", X509_get_subject_name(cert),
 290                     "sender field", msg->header->sender->d.directoryName))
 291         return 0;
 292
 293     if (!check_kid(ctx, cert, msg->header->senderKID))
 294         return 0;
 295     /* acceptable also if there is no senderKID in msg header */
 296     ossl_cmp_info(ctx, " cert seems acceptable");
 297     return 1;
 298 }
 299
 300 static int check_msg_valid_cert(OSSL_CMP_CTX *ctx, X509_STORE *store,
 301                                 X509 *scrt, const OSSL_CMP_MSG *msg)
 302 {
 303     if (!verify_signature(ctx, msg, scrt)) {
 304         ossl_cmp_warn(ctx, "msg signature verification failed");
 305         return 0;
 306     }
 307     if (OSSL_CMP_validate_cert_path(ctx, store, scrt))
 308         return 1;
 309
 310     ossl_cmp_warn(ctx,
 311                   "msg signature validates but cert path validation failed");
 312     return 0;
 313 }
 314
 315 /*
 316  * Exceptional handling for 3GPP TS 33.310 [3G/LTE Network Domain Security
 317  * (NDS); Authentication Framework (AF)], only to use for IP messages
 318  * and if the ctx option is explicitly set: use self-issued certificates
 319  * from extraCerts as trust anchor to validate sender cert and msg -
 320  * provided it also can validate the newly enrolled certificate
 321  */
 322 static int check_msg_valid_cert_3gpp(OSSL_CMP_CTX *ctx, X509 *scrt,
 323                                      const OSSL_CMP_MSG *msg)
 324 {
 325     int valid = 0;
 326     X509_STORE *store;
 327
 328     if (!ctx->permitTAInExtraCertsForIR)
 329         return 0;
 330
 331     if ((store = X509_STORE_new()) == NULL
 332             || !ossl_cmp_X509_STORE_add1_certs(store, msg->extraCerts,
 333                                                1 /* self-issued only */))
 334         goto err;
 335
 336     /* store does not include CRLs */
 337     valid = OSSL_CMP_validate_cert_path(ctx, store, scrt);
 338     if (!valid) {
 339         ossl_cmp_warn(ctx,
 340                       "also exceptional 3GPP mode cert path validation failed");
 341     } else {
 342         /*
 343          * verify that the newly enrolled certificate (which assumed rid ==
 344          * OSSL_CMP_CERTREQID) can also be validated with the same trusted store
 345          */
 346         EVP_PKEY *privkey = OSSL_CMP_CTX_get0_newPkey(ctx, 1);
 347         OSSL_CMP_CERTRESPONSE *crep =
 348             ossl_cmp_certrepmessage_get0_certresponse(msg->body->value.ip,
 349                                                       OSSL_CMP_CERTREQID);
 350         X509 *newcrt = ossl_cmp_certresponse_get1_certificate(privkey, crep);
 351         /*
 352          * maybe better use get_cert_status() from cmp_client.c, which catches
 353          * errors
 354          */
 355         valid = OSSL_CMP_validate_cert_path(ctx, store, newcrt);
 356         X509_free(newcrt);
 357     }
 358
 359  err:
 360     X509_STORE_free(store);
 361     return valid;
 362 }
 363
 364 /*
 365  * Try all certs in given list for verifying msg, normally or in 3GPP mode.
 366  * If already_checked1 == NULL then certs are assumed to be the msg->extraCerts.
 367  */
 368 static int check_msg_with_certs(OSSL_CMP_CTX *ctx, STACK_OF(X509) *certs,
 369                                 const char *desc,
 370                                 const STACK_OF(X509) *already_checked1,
 371                                 const STACK_OF(X509) *already_checked2,
 372                                 const OSSL_CMP_MSG *msg, int mode_3gpp)
 373 {
 374     int in_extraCerts = already_checked1 == NULL;
 375     int n_acceptable_certs = 0;
 376     int i;
 377
 378     if (sk_X509_num(certs) <= 0) {
 379         ossl_cmp_log1(WARN, ctx, "no %s", desc);
 380         return 0;
 381     }
 382
 383     for (i = 0; i < sk_X509_num(certs); i++) { /* certs may be NULL */
 384         X509 *cert = sk_X509_value(certs, i);
 385
 386         if (!ossl_assert(cert != NULL))
 387             return 0;
 388         if (!cert_acceptable(ctx, "cert from", desc, cert,
 389                              already_checked1, already_checked2, msg))
 390             continue;
 391         n_acceptable_certs++;
 392         if (mode_3gpp ? check_msg_valid_cert_3gpp(ctx, cert, msg)
 393                       : check_msg_valid_cert(ctx, ctx->trusted, cert, msg)) {
 394             /* store successful sender cert for further msgs in transaction */
 395             if (!X509_up_ref(cert))
 396                 return 0;
 397             if (!ossl_cmp_ctx_set0_validatedSrvCert(ctx, cert)) {
 398                 X509_free(cert);
 399                 return 0;
 400             }
 401             return 1;
 402         }
 403     }
 404     if (in_extraCerts && n_acceptable_certs == 0)
 405         ossl_cmp_warn(ctx, "no acceptable cert in extraCerts");
 406     return 0;
 407 }
 408
 409 /*
 410  * Verify msg trying first ctx->untrusted_certs, which should include extraCerts
 411  * at its front, then trying the trusted certs in truststore (if any) of ctx.
 412  */
 413 static int check_msg_all_certs(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 414                                int mode_3gpp)
 415 {
 416     int ret = 0;
 417
 418     if (mode_3gpp
 419             && ((!ctx->permitTAInExtraCertsForIR
 420                      || ossl_cmp_msg_get_bodytype(msg) != OSSL_CMP_PKIBODY_IP)))
 421         return 0;
 422
 423     ossl_cmp_info(ctx,
 424                   mode_3gpp ? "normal mode failed; trying now 3GPP mode trusting extraCerts"
 425                             : "trying first normal mode using trust store");
 426     if (check_msg_with_certs(ctx, msg->extraCerts, "extraCerts",
 427                              NULL, NULL, msg, mode_3gpp))
 428         return 1;
 429     if (check_msg_with_certs(ctx, ctx->untrusted_certs, "untrusted certs",
 430                              msg->extraCerts, NULL, msg, mode_3gpp))
 431         return 1;
 432
 433     if (ctx->trusted == NULL) {
 434         ossl_cmp_warn(ctx, mode_3gpp ? "no self-issued extraCerts"
 435                                      : "no trusted store");
 436     } else {
 437         STACK_OF(X509) *trusted = X509_STORE_get1_all_certs(ctx->trusted);
 438         ret = check_msg_with_certs(ctx, trusted,
 439                                    mode_3gpp ? "self-issued extraCerts"
 440                                              : "certs in trusted store",
 441                                    msg->extraCerts, ctx->untrusted_certs,
 442                                    msg, mode_3gpp);
 443         sk_X509_pop_free(trusted, X509_free);
 444     }
 445     return ret;
 446 }
 447
 448 static int no_log_cb(const char *func, const char *file, int line,
 449                      OSSL_CMP_severity level, const char *msg)
 450 {
 451     return 1;
 452 }
 453
 454 /* verify message signature with any acceptable and valid candidate cert */
 455 static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 456 {
 457     X509 *scrt = ctx->validatedSrvCert; /* previous successful sender cert */
 458     GENERAL_NAME *sender = msg->header->sender;
 459     char *sname = NULL;
 460     char *skid_str = NULL;
 461     const ASN1_OCTET_STRING *skid = msg->header->senderKID;
 462     OSSL_CMP_log_cb_t backup_log_cb = ctx->log_cb;
 463     int res = 0;
 464
 465     if (sender == NULL || msg->body == NULL)
 466         return 0; /* other NULL cases already have been checked */
 467     if (sender->type != GEN_DIRNAME) {
 468         CMPerr(0, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 469         return 0;
 470     }
 471
 472     /* dump any hitherto errors to avoid confusion when printing further ones */
 473     OSSL_CMP_CTX_print_errors(ctx);
 474
 475     /*
 476      * try first cached scrt, used successfully earlier in same transaction,
 477      * for validating this and any further msgs where extraCerts may be left out
 478      */
 479     if (scrt != NULL) {
 480         (void)ERR_set_mark();
 481         ossl_cmp_info(ctx,
 482                       "trying to verify msg signature with previously validated cert");
 483         if (cert_acceptable(ctx, "previously validated", "sender cert", scrt,
 484                             NULL, NULL, msg)
 485                 && (check_msg_valid_cert(ctx, ctx->trusted, scrt, msg)
 486                     || check_msg_valid_cert_3gpp(ctx, scrt, msg))) {
 487             (void)ERR_pop_to_mark();
 488             return 1;
 489         }
 490         (void)ERR_pop_to_mark();
 491         /* cached sender cert has shown to be no more successfully usable */
 492         (void)ossl_cmp_ctx_set0_validatedSrvCert(ctx, NULL);
 493     }
 494
 495     /* enable clearing irrelevant errors in attempts to validate sender certs */
 496     (void)ERR_set_mark();
 497     ctx->log_cb = no_log_cb; /* temporarily disable logging */
 498     res = check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */)
 499             || check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 500     ctx->log_cb = backup_log_cb;
 501     if (res) {
 502         /* discard any diagnostic information on trying to use certs */
 503         (void)ERR_pop_to_mark();
 504         goto end;
 505     }
 506     /* failed finding a sender cert that verifies the message signature */
 507     (void)ERR_clear_last_mark();
 508
 509     sname = X509_NAME_oneline(sender->d.directoryName, NULL, 0);
 510     skid_str = skid == NULL ? NULL
 511                             : OPENSSL_buf2hexstr(skid->data, skid->length);
 512     if (ctx->log_cb != NULL) {
 513         ossl_cmp_info(ctx, "trying to verify msg signature with a valid cert that..");
 514         if (sname != NULL)
 515             ossl_cmp_log1(INFO, ctx, "matches msg sender    = %s", sname);
 516         if (skid_str != NULL)
 517             ossl_cmp_log1(INFO, ctx, "matches msg senderKID = %s", skid_str);
 518         else
 519             ossl_cmp_info(ctx, "while msg header does not contain senderKID");
 520         /* re-do the above checks (just) for adding diagnostic information */
 521         check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */);
 522         check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
 523     }
 524
 525     CMPerr(0, CMP_R_NO_SUITABLE_SENDER_CERT);
 526     if (sname != NULL) {
 527         ERR_add_error_txt(NULL, "for msg sender name = ");
 528         ERR_add_error_txt(NULL, sname);
 529     }
 530     if (skid_str != NULL) {
 531         ERR_add_error_txt(" and ", "for msg senderKID = ");
 532         ERR_add_error_txt(NULL, skid_str);
 533     }
 534
 535  end:
 536     OPENSSL_free(sname);
 537     OPENSSL_free(skid_str);
 538     return res;
 539 }
 540
 541 /*
 542  * Validate the protection of the given PKIMessage using either password-
 543  * based mac (PBM) or a signature algorithm. In the case of signature algorithm,
 544  * the sender certificate can have been pinned by providing it in ctx->srvCert,
 545  * else it is searched in msg->extraCerts, ctx->untrusted_certs, in ctx->trusted
 546  * (in this order) and is path is validated against ctx->trusted.
 547  *
 548  * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,
 549  * the trust anchor for validating the IP msg may be taken from msg->extraCerts
 550  * if a self-issued certificate is found there that can be used to
 551  * validate the enrolled certificate returned in the IP.
 552  * This is according to the need given in 3GPP TS 33.310.
 553  *
 554  * Returns 1 on success, 0 on error or validation failed.
 555  */
 556 int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
 557 {
 558     X509_ALGOR *alg;
 559     int nid = NID_undef, pk_nid = NID_undef;
 560     const ASN1_OBJECT *algorOID = NULL;
 561     X509 *scrt;
 562     const X509_NAME *expected_sender;
 563
 564     if (ctx == NULL || msg == NULL
 565             || msg->header == NULL || msg->body == NULL) {
 566         CMPerr(0, CMP_R_NULL_ARGUMENT);
 567         return 0;
 568     }
 569
 570     /* validate sender name of received msg */
 571     if (msg->header->sender->type != GEN_DIRNAME) {
 572         CMPerr(0, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
 573         return 0; /* TODO FR#42: support for more than X509_NAME */
 574     }
 575     /*
 576      * Compare actual sender name of response with expected sender name.
 577      * Mitigates risk to accept misused PBM secret
 578      * or misused certificate of an unauthorized entity of a trusted hierarchy.
 579      */
 580     expected_sender = ctx->expected_sender;
 581     if (expected_sender == NULL && ctx->srvCert != NULL)
 582         expected_sender = X509_get_subject_name(ctx->srvCert);
 583     if (!check_name(ctx, "sender DN field",
 584                     msg->header->sender->d.directoryName,
 585                     "expected sender", expected_sender))
 586         return 0;
 587     /* Note: if recipient was NULL-DN it could be learned here if needed */
 588
 589     if ((alg = msg->header->protectionAlg) == NULL /* unprotected message */
 590             || msg->protection == NULL || msg->protection->data == NULL) {
 591         CMPerr(0, CMP_R_MISSING_PROTECTION);
 592         return 0;
 593     }
 594
 595     /* determine the nid for the used protection algorithm */
 596     X509_ALGOR_get0(&algorOID, NULL, NULL, alg);
 597     nid = OBJ_obj2nid(algorOID);
 598
 599     switch (nid) {
 600         /* 5.1.3.1.  Shared Secret Information */
 601     case NID_id_PasswordBasedMAC:
 602         if (ctx->secretValue == 0) {
 603             CMPerr(0, CMP_R_CHECKING_PBM_NO_SECRET_AVAILABLE);
 604             break;
 605         }
 606
 607         if (verify_PBMAC(msg, ctx->secretValue)) {
 608             /*
 609              * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
 610              * "shared secret information", then any certificate transported in
 611              * the caPubs field may be directly trusted as a root CA
 612              * certificate by the initiator.'
 613              */
 614             switch (ossl_cmp_msg_get_bodytype(msg)) {
 615             case -1:
 616                 return 0;
 617             case OSSL_CMP_PKIBODY_IP:
 618             case OSSL_CMP_PKIBODY_CP:
 619             case OSSL_CMP_PKIBODY_KUP:
 620             case OSSL_CMP_PKIBODY_CCP:
 621                 if (ctx->trusted != NULL) {
 622                     STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
 623                     /* value.ip is same for cp, kup, and ccp */
 624
 625                     if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
 626                         /* adds both self-issued and not self-issued certs */
 627                         return 0;
 628                 }
 629                 break;
 630             default:
 631                 break;
 632             }
 633             return 1;
 634         }
 635         break;
 636
 637         /*
 638          * 5.1.3.2 DH Key Pairs
 639          * Not yet supported
 640          */
 641     case NID_id_DHBasedMac:
 642         CMPerr(0, CMP_R_UNSUPPORTED_PROTECTION_ALG_DHBASEDMAC);
 643         break;
 644
 645         /*
 646          * 5.1.3.3.  Signature
 647          */
 648     default:
 649         if (!OBJ_find_sigid_algs(OBJ_obj2nid(alg->algorithm), NULL, &pk_nid)
 650                 || pk_nid == NID_undef) {
 651             CMPerr(0, CMP_R_UNKNOWN_ALGORITHM_ID);
 652             break;
 653         }
 654         scrt = ctx->srvCert;
 655         if (scrt == NULL) {
 656             if (check_msg_find_cert(ctx, msg))
 657                 return 1;
 658         } else { /* use pinned sender cert */
 659             /* use ctx->srvCert for signature check even if not acceptable */
 660             if (verify_signature(ctx, msg, scrt))
 661                 return 1;
 662             ossl_cmp_warn(ctx, "msg signature verification failed");
 663             CMPerr(0, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);
 664         }
 665         break;
 666     }
 667     return 0;
 668 }
 669
 670
 671 /*-
 672  * Check received message (i.e., response by server or request from client)
 673  * Any msg->extraCerts are prepended to ctx->untrusted_certs
 674  *
 675  * Ensures that:
 676  * it has a valid body type
 677  * its protection is valid (or invalid/absent, but only if a callback function
 678  *     is present and yields a positive result using also the supplied argument)
 679  * its transaction ID matches the previous transaction ID stored in ctx (if any)
 680  * its recipNonce matches the previous senderNonce stored in the ctx (if any)
 681  *
 682  * If everything is fine:
 683  * learns the senderNonce from the received message,
 684  * learns the transaction ID if it is not yet in ctx.
 685  *
 686  * returns body type (which is >= 0) of the message on success, -1 on error
 687  */
 688 int ossl_cmp_msg_check_received(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
 689                                 ossl_cmp_allow_unprotected_cb_t cb, int cb_arg)
 690 {
 691     int rcvd_type;
 692
 693     if (!ossl_assert(ctx != NULL && msg != NULL))
 694         return -1;
 695
 696     if (sk_X509_num(msg->extraCerts) > 10)
 697         ossl_cmp_warn(ctx,
 698                       "received CMP message contains more than 10 extraCerts");
 699
 700     /* validate message protection */
 701     if (msg->header->protectionAlg != 0) {
 702         /* detect explicitly permitted exceptions for invalid protection */
 703         if (!OSSL_CMP_validate_msg(ctx, msg)
 704                 && (cb == NULL || (*cb)(ctx, msg, 1, cb_arg) <= 0)) {
 705 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 706             CMPerr(0, CMP_R_ERROR_VALIDATING_PROTECTION);
 707             return -1;
 708 #endif
 709         }
 710     } else {
 711         /* detect explicitly permitted exceptions for missing protection */
 712         if (cb == NULL || (*cb)(ctx, msg, 0, cb_arg) <= 0) {
 713 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 714             CMPerr(0, CMP_R_MISSING_PROTECTION);
 715             return -1;
 716 #endif
 717         }
 718     }
 719
 720     /* check CMP version number in header */
 721     if (ossl_cmp_hdr_get_pvno(OSSL_CMP_MSG_get0_header(msg)) != OSSL_CMP_PVNO) {
 722 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 723         CMPerr(0, CMP_R_UNEXPECTED_PVNO);
 724         return -1;
 725 #endif
 726     }
 727
 728     if ((rcvd_type = ossl_cmp_msg_get_bodytype(msg)) < 0) {
 729 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 730         CMPerr(0, CMP_R_PKIBODY_ERROR);
 731         return -1;
 732 #endif
 733     }
 734
 735     /* compare received transactionID with the expected one in previous msg */
 736     if (ctx->transactionID != NULL
 737             && (msg->header->transactionID == NULL
 738                 || ASN1_OCTET_STRING_cmp(ctx->transactionID,
 739                                          msg->header->transactionID) != 0)) {
 740 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 741         CMPerr(0, CMP_R_TRANSACTIONID_UNMATCHED);
 742         return -1;
 743 #endif
 744     }
 745
 746     /* compare received nonce with the one we sent */
 747     if (ctx->senderNonce != NULL
 748             && (msg->header->recipNonce == NULL
 749                 || ASN1_OCTET_STRING_cmp(ctx->senderNonce,
 750                                          msg->header->recipNonce) != 0)) {
 751 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 752         CMPerr(0, CMP_R_RECIPNONCE_UNMATCHED);
 753         return -1;
 754 #endif
 755     }
 756
 757     /*
 758      * RFC 4210 section 5.1.1 states: the recipNonce is copied from
 759      * the senderNonce of the previous message in the transaction.
 760      * --> Store for setting in next message
 761      */
 762     if (!ossl_cmp_ctx_set1_recipNonce(ctx, msg->header->senderNonce))
 763         return -1;
 764
 765     /* if not yet present, learn transactionID */
 766     if (ctx->transactionID == NULL
 767         && !OSSL_CMP_CTX_set1_transactionID(ctx, msg->header->transactionID))
 768         return -1;
 769
 770     /*
 771      * Store any provided extraCerts in ctx for future use,
 772      * such that they are available to ctx->certConf_cb and
 773      * the peer does not need to send them again in the same transaction.
 774      * For efficiency, the extraCerts are prepended so they get used first.
 775      */
 776     if (!ossl_cmp_sk_X509_add1_certs(ctx->untrusted_certs, msg->extraCerts,
 777                                      0 /* this allows self-issued certs */,
 778                                      1 /* no_dups */, 1 /* prepend */))
 779         return -1;
 780
 781     return rcvd_type;
 782 }
 783
 784 int ossl_cmp_verify_popo(const OSSL_CMP_MSG *msg, int accept_RAVerified)
 785 {
 786     if (!ossl_assert(msg != NULL && msg->body != NULL))
 787         return 0;
 788     switch (msg->body->type) {
 789     case OSSL_CMP_PKIBODY_P10CR:
 790         {
 791             X509_REQ *req = msg->body->value.p10cr;
 792
 793             if (X509_REQ_verify(req, X509_REQ_get0_pubkey(req)) <= 0) {
 794 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 795                 CMPerr(0, CMP_R_REQUEST_NOT_ACCEPTED);
 796                 return 0;
 797 #endif
 798             }
 799         }
 800         break;
 801     case OSSL_CMP_PKIBODY_IR:
 802     case OSSL_CMP_PKIBODY_CR:
 803     case OSSL_CMP_PKIBODY_KUR:
 804         if (!OSSL_CRMF_MSGS_verify_popo(msg->body->value.ir, OSSL_CMP_CERTREQID,
 805                                         accept_RAVerified)) {
 806 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 807             return 0;
 808 #endif
 809         }
 810         break;
 811     default:
 812         CMPerr(0, CMP_R_PKIBODY_ERROR);
 813         return 0;
 814     }
 815     return 1;
 816 }