crypto/cmp/cmp_protect.c

   1 /*
   2  * Copyright 2007-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright Nokia 2007-2019
   4  * Copyright Siemens AG 2015-2019
   5  *
   6  * Licensed under the Apache License 2.0 (the "License").  You may not use
   7  * this file except in compliance with the License.  You can obtain a copy
   8  * in the file LICENSE in the source distribution or at
   9  * https://www.openssl.org/source/license.html
  10  */
  11
  12 #include "cmp_local.h"
  13
  14 /* explicit #includes not strictly needed since implied by the above: */
  15 #include <openssl/asn1t.h>
  16 #include <openssl/cmp.h>
  17 #include <openssl/crmf.h>
  18 #include <openssl/err.h>
  19 #include <openssl/x509.h>
  20
  21 DEFINE_STACK_OF(X509)
  22
  23 /*
  24  * This function is also used for verification from cmp_vfy.
  25  *
  26  * Calculate protection for given PKImessage utilizing the given credentials
  27  * and the algorithm parameters set inside the message header's protectionAlg.
  28  *
  29  * secret or pkey must be set. Attempts doing PBMAC in case 'secret' is set
  30  * and else signature if 'pkey' is set - but will only
  31  * do the protection already marked in msg->header->protectionAlg.
  32  *
  33  * returns ptr to ASN1_BIT_STRING containing protection on success, else NULL
  34  */
  35 ASN1_BIT_STRING *ossl_cmp_calc_protection(const OSSL_CMP_MSG *msg,
  36                                           const ASN1_OCTET_STRING *secret,
  37                                           EVP_PKEY *pkey)
  38 {
  39     ASN1_BIT_STRING *prot = NULL;
  40     OSSL_CMP_PROTECTEDPART prot_part;
  41     const ASN1_OBJECT *algorOID = NULL;
  42     int len;
  43     size_t prot_part_der_len;
  44     unsigned char *prot_part_der = NULL;
  45     size_t sig_len;
  46     unsigned char *protection = NULL;
  47     const void *ppval = NULL;
  48     int pptype = 0;
  49     OSSL_CRMF_PBMPARAMETER *pbm = NULL;
  50     ASN1_STRING *pbm_str = NULL;
  51     const unsigned char *pbm_str_uc = NULL;
  52     EVP_MD_CTX *evp_ctx = NULL;
  53     int md_NID;
  54     const EVP_MD *md = NULL;
  55
  56     if (!ossl_assert(msg != NULL))
  57         return NULL;
  58
  59     /* construct data to be signed */
  60     prot_part.header = msg->header;
  61     prot_part.body = msg->body;
  62
  63     len = i2d_OSSL_CMP_PROTECTEDPART(&prot_part, &prot_part_der);
  64     if (len < 0 || prot_part_der == NULL) {
  65         CMPerr(0, CMP_R_ERROR_CALCULATING_PROTECTION);
  66         goto end;
  67     }
  68     prot_part_der_len = (size_t) len;
  69
  70     if (msg->header->protectionAlg == NULL) {
  71         CMPerr(0, CMP_R_UNKNOWN_ALGORITHM_ID);
  72         goto end;
  73     }
  74     X509_ALGOR_get0(&algorOID, &pptype, &ppval, msg->header->protectionAlg);
  75
  76     if (secret != NULL) {
  77         if (ppval == NULL) {
  78             CMPerr(0, CMP_R_ERROR_CALCULATING_PROTECTION);
  79             goto end;
  80         }
  81         if (NID_id_PasswordBasedMAC != OBJ_obj2nid(algorOID)) {
  82             CMPerr(0, CMP_R_WRONG_ALGORITHM_OID);
  83             goto end;
  84         }
  85         pbm_str = (ASN1_STRING *)ppval;
  86         pbm_str_uc = pbm_str->data;
  87         pbm = d2i_OSSL_CRMF_PBMPARAMETER(NULL, &pbm_str_uc, pbm_str->length);
  88         if (pbm == NULL) {
  89             CMPerr(0, CMP_R_WRONG_ALGORITHM_OID);
  90             goto end;
  91         }
  92
  93         if (!OSSL_CRMF_pbm_new(pbm, prot_part_der, prot_part_der_len,
  94                                secret->data, secret->length,
  95                                &protection, &sig_len))
  96             goto end;
  97     } else if (pkey != NULL) {
  98         /* TODO combine this with large parts of CRMF_poposigningkey_init() */
  99         /* EVP_DigestSignInit() checks that pkey type is correct for the alg */
 100
 101         if (!OBJ_find_sigid_algs(OBJ_obj2nid(algorOID), &md_NID, NULL)
 102                 || (md = EVP_get_digestbynid(md_NID)) == NULL
 103                 || (evp_ctx = EVP_MD_CTX_new()) == NULL) {
 104             CMPerr(0, CMP_R_UNKNOWN_ALGORITHM_ID);
 105             goto end;
 106         }
 107         if (EVP_DigestSignInit(evp_ctx, NULL, md, NULL, pkey) <= 0
 108                 || EVP_DigestSignUpdate(evp_ctx, prot_part_der,
 109                                         prot_part_der_len) <= 0
 110                 || EVP_DigestSignFinal(evp_ctx, NULL, &sig_len) <= 0
 111                 || (protection = OPENSSL_malloc(sig_len)) == NULL
 112                 || EVP_DigestSignFinal(evp_ctx, protection, &sig_len) <= 0) {
 113             CMPerr(0, CMP_R_ERROR_CALCULATING_PROTECTION);
 114             goto end;
 115         }
 116     } else {
 117         CMPerr(0, CMP_R_INVALID_ARGS);
 118         goto end;
 119     }
 120
 121     if ((prot = ASN1_BIT_STRING_new()) == NULL)
 122         goto end;
 123     /* OpenSSL defaults all bit strings to be encoded as ASN.1 NamedBitList */
 124     prot->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
 125     prot->flags |= ASN1_STRING_FLAG_BITS_LEFT;
 126     if (!ASN1_BIT_STRING_set(prot, protection, sig_len)) {
 127         ASN1_BIT_STRING_free(prot);
 128         prot = NULL;
 129     }
 130
 131  end:
 132     OSSL_CRMF_PBMPARAMETER_free(pbm);
 133     EVP_MD_CTX_free(evp_ctx);
 134     OPENSSL_free(protection);
 135     OPENSSL_free(prot_part_der);
 136     return prot;
 137 }
 138
 139 int ossl_cmp_msg_add_extraCerts(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)
 140 {
 141     if (!ossl_assert(ctx != NULL && msg != NULL))
 142         return 0;
 143
 144     if (msg->extraCerts == NULL
 145             && (msg->extraCerts = sk_X509_new_null()) == NULL)
 146         return 0;
 147
 148     if (ctx->cert != NULL && ctx->pkey != NULL) {
 149         /* make sure that our own cert is included in the first position */
 150         if (!X509_add_cert(msg->extraCerts, ctx->cert,
 151                            X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 152                            | X509_ADD_FLAG_PREPEND))
 153             return 0;
 154         /* if we have untrusted certs, try to add intermediate certs */
 155         if (ctx->untrusted_certs != NULL) {
 156             STACK_OF(X509) *chain =
 157                 ossl_cmp_build_cert_chain(ctx->libctx, ctx->propq,
 158                                           ctx->untrusted_certs, ctx->cert);
 159             int res = X509_add_certs(msg->extraCerts, chain,
 160                                      X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 161                                      | X509_ADD_FLAG_NO_SS);
 162
 163             sk_X509_pop_free(chain, X509_free);
 164             if (res == 0)
 165                 return 0;
 166         }
 167     }
 168
 169     /* add any additional certificates from ctx->extraCertsOut */
 170     if (!X509_add_certs(msg->extraCerts, ctx->extraCertsOut,
 171                         X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP))
 172         return 0;
 173
 174     /* if none was found avoid empty ASN.1 sequence */
 175     if (sk_X509_num(msg->extraCerts) == 0) {
 176         sk_X509_free(msg->extraCerts);
 177         msg->extraCerts = NULL;
 178     }
 179     return 1;
 180 }
 181
 182 /*
 183  * Create an X509_ALGOR structure for PasswordBasedMAC protection based on
 184  * the pbm settings in the context
 185  * returns pointer to X509_ALGOR on success, NULL on error
 186  */
 187 static X509_ALGOR *create_pbmac_algor(OSSL_CMP_CTX *ctx)
 188 {
 189     X509_ALGOR *alg = NULL;
 190     OSSL_CRMF_PBMPARAMETER *pbm = NULL;
 191     unsigned char *pbm_der = NULL;
 192     int pbm_der_len;
 193     ASN1_STRING *pbm_str = NULL;
 194
 195     if (!ossl_assert(ctx != NULL))
 196         return NULL;
 197
 198     alg = X509_ALGOR_new();
 199     pbm = OSSL_CRMF_pbmp_new(ctx->libctx, ctx->pbm_slen,
 200                              ctx->pbm_owf, ctx->pbm_itercnt, ctx->pbm_mac);
 201     pbm_str = ASN1_STRING_new();
 202     if (alg == NULL || pbm == NULL || pbm_str == NULL)
 203         goto err;
 204
 205     if ((pbm_der_len = i2d_OSSL_CRMF_PBMPARAMETER(pbm, &pbm_der)) < 0)
 206         goto err;
 207
 208     if (!ASN1_STRING_set(pbm_str, pbm_der, pbm_der_len))
 209         goto err;
 210     OPENSSL_free(pbm_der);
 211
 212     X509_ALGOR_set0(alg, OBJ_nid2obj(NID_id_PasswordBasedMAC),
 213                     V_ASN1_SEQUENCE, pbm_str);
 214     OSSL_CRMF_PBMPARAMETER_free(pbm);
 215     return alg;
 216
 217  err:
 218     ASN1_STRING_free(pbm_str);
 219     X509_ALGOR_free(alg);
 220     OPENSSL_free(pbm_der);
 221     OSSL_CRMF_PBMPARAMETER_free(pbm);
 222     return NULL;
 223 }
 224
 225 int ossl_cmp_msg_protect(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)
 226 {
 227     if (!ossl_assert(ctx != NULL && msg != NULL))
 228         return 0;
 229
 230     /*
 231      * For the case of re-protection remove pre-existing protection.
 232      * TODO: Consider also removing any pre-existing extraCerts.
 233      */
 234     X509_ALGOR_free(msg->header->protectionAlg);
 235     msg->header->protectionAlg = NULL;
 236     ASN1_BIT_STRING_free(msg->protection);
 237     msg->protection = NULL;
 238
 239     if (ctx->unprotectedSend)
 240         return 1;
 241
 242     /* use PasswordBasedMac according to 5.1.3.1 if secretValue is given */
 243     if (ctx->secretValue != NULL) {
 244         if ((msg->header->protectionAlg = create_pbmac_algor(ctx)) == NULL)
 245             goto err;
 246         if (ctx->referenceValue != NULL
 247                 && !ossl_cmp_hdr_set1_senderKID(msg->header,
 248                                                 ctx->referenceValue))
 249             goto err;
 250     } else if (ctx->cert != NULL && ctx->pkey != NULL) {
 251         /*
 252          * use MSG_SIG_ALG according to 5.1.3.3 if client Certificate and
 253          * private key is given
 254          */
 255         const ASN1_OCTET_STRING *subjKeyIDStr = NULL;
 256         int algNID = 0;
 257         ASN1_OBJECT *alg = NULL;
 258
 259         /* make sure that key and certificate match */
 260         if (!X509_check_private_key(ctx->cert, ctx->pkey)) {
 261             CMPerr(0, CMP_R_CERT_AND_KEY_DO_NOT_MATCH);
 262             goto err;
 263         }
 264
 265         if ((msg->header->protectionAlg = X509_ALGOR_new()) == NULL)
 266             goto err;
 267         if (!OBJ_find_sigid_by_algs(&algNID, ctx->digest,
 268                                     EVP_PKEY_id(ctx->pkey))) {
 269             CMPerr(0, CMP_R_UNSUPPORTED_KEY_TYPE);
 270             goto err;
 271         }
 272         if ((alg = OBJ_nid2obj(algNID)) == NULL)
 273             goto err;
 274         if (!X509_ALGOR_set0(msg->header->protectionAlg, alg,
 275                              V_ASN1_UNDEF, NULL)) {
 276             ASN1_OBJECT_free(alg);
 277             goto err;
 278         }
 279
 280         /*
 281          * set senderKID to keyIdentifier of the used certificate according
 282          * to section 5.1.1
 283          */
 284         subjKeyIDStr = X509_get0_subject_key_id(ctx->cert);
 285         if (subjKeyIDStr == NULL)
 286             subjKeyIDStr = ctx->referenceValue; /* fallback */
 287         if (subjKeyIDStr != NULL
 288                 && !ossl_cmp_hdr_set1_senderKID(msg->header, subjKeyIDStr))
 289             goto err;
 290     } else {
 291         CMPerr(0, CMP_R_MISSING_KEY_INPUT_FOR_CREATING_PROTECTION);
 292         goto err;
 293     }
 294     if ((msg->protection =
 295          ossl_cmp_calc_protection(msg, ctx->secretValue, ctx->pkey)) == NULL)
 296         goto err;
 297
 298     /*
 299      * If present, add ctx->cert followed by its chain as far as possible.
 300      * Finally add any additional certificates from ctx->extraCertsOut;
 301      * even if not needed to validate the protection
 302      * the option to do this might be handy for certain use cases.
 303      */
 304     if (!ossl_cmp_msg_add_extraCerts(ctx, msg))
 305         goto err;
 306
 307     /*
 308      * As required by RFC 4210 section 5.1.1., if the sender name is not known
 309      * to the client it set to NULL-DN. In this case for identification at least
 310      * the senderKID must be set, where we took the referenceValue as fallback.
 311      */
 312     if (ossl_cmp_general_name_is_NULL_DN(msg->header->sender)
 313             && msg->header->senderKID == NULL)
 314         CMPerr(0, CMP_R_MISSING_SENDER_IDENTIFICATION);
 315     else
 316         return 1;
 317
 318  err:
 319     CMPerr(0, CMP_R_ERROR_PROTECTING_MESSAGE);
 320     return 0;
 321 }