crypto/cmp/cmp_protect.c

   1 /*
   2  * Copyright 2007-2021 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 /*
  22  * This function is also used by the internal verify_PBMAC() in cmp_vfy.c.
  23  *
  24  * Calculate protection for given PKImessage according to
  25  * the algorithm and parameters in the message header's protectionAlg
  26  * using the credentials, library context, and property criteria in the ctx.
  27  *
  28  * returns ASN1_BIT_STRING representing the protection on success, else NULL
  29  */
  30 ASN1_BIT_STRING *ossl_cmp_calc_protection(const OSSL_CMP_CTX *ctx,
  31                                           const OSSL_CMP_MSG *msg)
  32 {
  33     ASN1_BIT_STRING *prot = NULL;
  34     OSSL_CMP_PROTECTEDPART prot_part;
  35     const ASN1_OBJECT *algorOID = NULL;
  36     const void *ppval = NULL;
  37     int pptype = 0;
  38
  39     if (!ossl_assert(ctx != NULL && msg != NULL))
  40         return NULL;
  41
  42     /* construct data to be signed */
  43     prot_part.header = msg->header;
  44     prot_part.body = msg->body;
  45
  46     if (msg->header->protectionAlg == NULL) {
  47         ERR_raise(ERR_LIB_CMP, CMP_R_UNKNOWN_ALGORITHM_ID);
  48         return NULL;
  49     }
  50     X509_ALGOR_get0(&algorOID, &pptype, &ppval, msg->header->protectionAlg);
  51
  52     if (OBJ_obj2nid(algorOID) == NID_id_PasswordBasedMAC) {
  53         int len;
  54         size_t prot_part_der_len;
  55         unsigned char *prot_part_der = NULL;
  56         size_t sig_len;
  57         unsigned char *protection = NULL;
  58         OSSL_CRMF_PBMPARAMETER *pbm = NULL;
  59         ASN1_STRING *pbm_str = NULL;
  60         const unsigned char *pbm_str_uc = NULL;
  61
  62         if (ctx->secretValue == NULL) {
  63             ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PBM_SECRET);
  64             return NULL;
  65         }
  66         if (ppval == NULL) {
  67             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CALCULATING_PROTECTION);
  68             return NULL;
  69         }
  70
  71         len = i2d_OSSL_CMP_PROTECTEDPART(&prot_part, &prot_part_der);
  72         if (len < 0 || prot_part_der == NULL) {
  73             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CALCULATING_PROTECTION);
  74             goto end;
  75         }
  76         prot_part_der_len = (size_t)len;
  77
  78         pbm_str = (ASN1_STRING *)ppval;
  79         pbm_str_uc = pbm_str->data;
  80         pbm = d2i_OSSL_CRMF_PBMPARAMETER(NULL, &pbm_str_uc, pbm_str->length);
  81         if (pbm == NULL) {
  82             ERR_raise(ERR_LIB_CMP, CMP_R_WRONG_ALGORITHM_OID);
  83             goto end;
  84         }
  85
  86         if (!OSSL_CRMF_pbm_new(ctx->libctx, ctx->propq,
  87                                pbm, prot_part_der, prot_part_der_len,
  88                                ctx->secretValue->data, ctx->secretValue->length,
  89                                &protection, &sig_len))
  90             goto end;
  91
  92         if ((prot = ASN1_BIT_STRING_new()) == NULL)
  93             return NULL;
  94         /* OpenSSL defaults all bit strings to be encoded as ASN.1 NamedBitList */
  95         prot->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
  96         prot->flags |= ASN1_STRING_FLAG_BITS_LEFT;
  97         if (!ASN1_BIT_STRING_set(prot, protection, sig_len)) {
  98             ASN1_BIT_STRING_free(prot);
  99             prot = NULL;
 100         }
 101     end:
 102         OSSL_CRMF_PBMPARAMETER_free(pbm);
 103         OPENSSL_free(protection);
 104         OPENSSL_free(prot_part_der);
 105         return prot;
 106     } else {
 107         int md_nid;
 108         const EVP_MD *md = NULL;
 109
 110         if (ctx->pkey == NULL) {
 111             ERR_raise(ERR_LIB_CMP,
 112                       CMP_R_MISSING_KEY_INPUT_FOR_CREATING_PROTECTION);
 113             return NULL;
 114         }
 115         if (!OBJ_find_sigid_algs(OBJ_obj2nid(algorOID), &md_nid, NULL)
 116                 || (md = EVP_get_digestbynid(md_nid)) == NULL) {
 117             ERR_raise(ERR_LIB_CMP, CMP_R_UNKNOWN_ALGORITHM_ID);
 118             return NULL;
 119         }
 120
 121         if ((prot = ASN1_BIT_STRING_new()) == NULL)
 122             return NULL;
 123         if (ASN1_item_sign_ex(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART), NULL,
 124                               NULL, prot, &prot_part, NULL, ctx->pkey, md,
 125                               ctx->libctx, ctx->propq))
 126             return prot;
 127         ASN1_BIT_STRING_free(prot);
 128         return NULL;
 129     }
 130 }
 131
 132 int ossl_cmp_msg_add_extraCerts(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)
 133 {
 134     if (!ossl_assert(ctx != NULL && msg != NULL))
 135         return 0;
 136
 137     /* Add first ctx->cert and its chain if using signature-based protection */
 138     if (!ctx->unprotectedSend && ctx->secretValue == NULL
 139             && ctx->cert != NULL && ctx->pkey != NULL) {
 140         int prepend = X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
 141             | X509_ADD_FLAG_PREPEND | X509_ADD_FLAG_NO_SS;
 142
 143         /* if not yet done try to build chain using available untrusted certs */
 144         if (ctx->chain == NULL) {
 145             ossl_cmp_debug(ctx,
 146                            "trying to build chain for own CMP signer cert");
 147             ctx->chain =
 148                 ossl_cmp_build_cert_chain(ctx->libctx, ctx->propq, NULL,
 149                                           ctx->untrusted, ctx->cert);
 150             if (ctx->chain != NULL) {
 151                 ossl_cmp_debug(ctx,
 152                                "success building chain for own CMP signer cert");
 153             } else {
 154                 /* dump errors to avoid confusion when printing further ones */
 155                 OSSL_CMP_CTX_print_errors(ctx);
 156                 ossl_cmp_warn(ctx,
 157                               "could not build chain for own CMP signer cert");
 158             }
 159         }
 160         if (ctx->chain != NULL) {
 161             if (!ossl_x509_add_certs_new(&msg->extraCerts, ctx->chain, prepend))
 162                 return 0;
 163         } else {
 164             /* make sure that at least our own signer cert is included first */
 165             if (!ossl_x509_add_cert_new(&msg->extraCerts, ctx->cert, prepend))
 166                 return 0;
 167             ossl_cmp_debug(ctx, "fallback: adding just own CMP signer cert");
 168         }
 169     }
 170
 171     /* add any additional certificates from ctx->extraCertsOut */
 172     if (!ossl_x509_add_certs_new(&msg->extraCerts, ctx->extraCertsOut,
 173                                  X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP))
 174         return 0;
 175
 176     /* in case extraCerts are empty list avoid empty ASN.1 sequence */
 177     if (sk_X509_num(msg->extraCerts) == 0) {
 178         sk_X509_free(msg->extraCerts);
 179         msg->extraCerts = NULL;
 180     }
 181     return 1;
 182 }
 183
 184 /*
 185  * Create an X509_ALGOR structure for PasswordBasedMAC protection based on
 186  * the pbm settings in the context
 187  */
 188 static int set_pbmac_algor(const OSSL_CMP_CTX *ctx, X509_ALGOR **alg)
 189 {
 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 0;
 197
 198     pbm = OSSL_CRMF_pbmp_new(ctx->libctx, ctx->pbm_slen,
 199                              EVP_MD_type(ctx->pbm_owf), ctx->pbm_itercnt,
 200                              ctx->pbm_mac);
 201     pbm_str = ASN1_STRING_new();
 202     if (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     if (*alg == NULL && (*alg = X509_ALGOR_new()) == NULL)
 211         goto err;
 212     OPENSSL_free(pbm_der);
 213
 214     X509_ALGOR_set0(*alg, OBJ_nid2obj(NID_id_PasswordBasedMAC),
 215                     V_ASN1_SEQUENCE, pbm_str);
 216     OSSL_CRMF_PBMPARAMETER_free(pbm);
 217     return 1;
 218
 219  err:
 220     ASN1_STRING_free(pbm_str);
 221     OPENSSL_free(pbm_der);
 222     OSSL_CRMF_PBMPARAMETER_free(pbm);
 223     return 0;
 224 }
 225
 226 static int set_sig_algor(const OSSL_CMP_CTX *ctx, X509_ALGOR **alg)
 227 {
 228     int nid = 0;
 229     ASN1_OBJECT *algo = NULL;
 230
 231     if (!OBJ_find_sigid_by_algs(&nid, EVP_MD_type(ctx->digest),
 232                                 EVP_PKEY_id(ctx->pkey))) {
 233         ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_KEY_TYPE);
 234         return 0;
 235     }
 236     if ((algo = OBJ_nid2obj(nid)) == NULL)
 237         return 0;
 238     if (*alg == NULL && (*alg = X509_ALGOR_new()) == NULL)
 239         return 0;
 240
 241     if (X509_ALGOR_set0(*alg, algo, V_ASN1_UNDEF, NULL))
 242         return 1;
 243     ASN1_OBJECT_free(algo);
 244     return 0;
 245 }
 246
 247 static int set_senderKID(const OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg,
 248                          const ASN1_OCTET_STRING *id)
 249 {
 250     if (id == NULL)
 251         id = ctx->referenceValue; /* standard for PBM, fallback for sig-based */
 252     return id == NULL || ossl_cmp_hdr_set1_senderKID(msg->header, id);
 253 }
 254
 255 int ossl_cmp_msg_protect(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)
 256 {
 257     if (!ossl_assert(ctx != NULL && msg != NULL))
 258         return 0;
 259
 260     /*
 261      * For the case of re-protection remove pre-existing protection.
 262      * TODO: Consider also removing any pre-existing extraCerts.
 263      */
 264     X509_ALGOR_free(msg->header->protectionAlg);
 265     msg->header->protectionAlg = NULL;
 266     ASN1_BIT_STRING_free(msg->protection);
 267     msg->protection = NULL;
 268
 269     if (ctx->unprotectedSend) {
 270         if (!set_senderKID(ctx, msg, NULL))
 271             goto err;
 272     } else if (ctx->secretValue != NULL) {
 273         /* use PasswordBasedMac according to 5.1.3.1 if secretValue is given */
 274         if (!set_pbmac_algor(ctx, &msg->header->protectionAlg))
 275             goto err;
 276         if (!set_senderKID(ctx, msg, NULL))
 277             goto err;
 278
 279         /*
 280          * will add any additional certificates from ctx->extraCertsOut
 281          * while not needed to validate the protection certificate,
 282          * the option to do this might be handy for certain use cases
 283          */
 284     } else if (ctx->cert != NULL && ctx->pkey != NULL) {
 285         /* use MSG_SIG_ALG according to 5.1.3.3 if client cert and key given */
 286
 287         /* make sure that key and certificate match */
 288         if (!X509_check_private_key(ctx->cert, ctx->pkey)) {
 289             ERR_raise(ERR_LIB_CMP, CMP_R_CERT_AND_KEY_DO_NOT_MATCH);
 290             goto err;
 291         }
 292
 293         if (!set_sig_algor(ctx, &msg->header->protectionAlg))
 294             goto err;
 295         /* set senderKID to keyIdentifier of the cert according to 5.1.1 */
 296         if (!set_senderKID(ctx, msg, X509_get0_subject_key_id(ctx->cert)))
 297             goto err;
 298
 299         /*
 300          * will add ctx->cert followed, if possible, by its chain built
 301          * from ctx->untrusted, and then ctx->extraCertsOut
 302          */
 303     } else {
 304         ERR_raise(ERR_LIB_CMP,
 305                   CMP_R_MISSING_KEY_INPUT_FOR_CREATING_PROTECTION);
 306         goto err;
 307     }
 308     if (!ctx->unprotectedSend
 309             && ((msg->protection = ossl_cmp_calc_protection(ctx, msg)) == NULL))
 310         goto err;
 311
 312     /*
 313      * For signature-based protection add ctx->cert followed by its chain.
 314      * Finally add any additional certificates from ctx->extraCertsOut;
 315      * even if not needed to validate the protection
 316      * the option to do this might be handy for certain use cases.
 317      */
 318     if (!ossl_cmp_msg_add_extraCerts(ctx, msg))
 319         goto err;
 320
 321     /*
 322      * As required by RFC 4210 section 5.1.1., if the sender name is not known
 323      * to the client it set to NULL-DN. In this case for identification at least
 324      * the senderKID must be set, where we took the referenceValue as fallback.
 325      */
 326     if (!(ossl_cmp_general_name_is_NULL_DN(msg->header->sender)
 327           && msg->header->senderKID == NULL))
 328         return 1;
 329     ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_SENDER_IDENTIFICATION);
 330
 331  err:
 332     ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_PROTECTING_MESSAGE);
 333     return 0;
 334 }