crypto/cms/cms_pwri.c

   1 /*
   2  * Copyright 2009-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include "internal/cryptlib.h"
  11 #include <openssl/asn1t.h>
  12 #include <openssl/pem.h>
  13 #include <openssl/x509v3.h>
  14 #include <openssl/err.h>
  15 #include <openssl/cms.h>
  16 #include <openssl/rand.h>
  17 #include <openssl/aes.h>
  18 #include "internal/sizes.h"
  19 #include "crypto/asn1.h"
  20 #include "cms_local.h"
  21
  22 int CMS_RecipientInfo_set0_password(CMS_RecipientInfo *ri,
  23                                     unsigned char *pass, ossl_ssize_t passlen)
  24 {
  25     CMS_PasswordRecipientInfo *pwri;
  26     if (ri->type != CMS_RECIPINFO_PASS) {
  27         ERR_raise(ERR_LIB_CMS, CMS_R_NOT_PWRI);
  28         return 0;
  29     }
  30
  31     pwri = ri->d.pwri;
  32     pwri->pass = pass;
  33     if (pass && passlen < 0)
  34         passlen = strlen((char *)pass);
  35     pwri->passlen = passlen;
  36     return 1;
  37 }
  38
  39 CMS_RecipientInfo *CMS_add0_recipient_password(CMS_ContentInfo *cms,
  40                                                int iter, int wrap_nid,
  41                                                int pbe_nid,
  42                                                unsigned char *pass,
  43                                                ossl_ssize_t passlen,
  44                                                const EVP_CIPHER *kekciph)
  45 {
  46     STACK_OF(CMS_RecipientInfo) *ris;
  47     CMS_RecipientInfo *ri = NULL;
  48     CMS_EncryptedContentInfo *ec;
  49     CMS_PasswordRecipientInfo *pwri;
  50     EVP_CIPHER_CTX *ctx = NULL;
  51     X509_ALGOR *encalg = NULL;
  52     unsigned char iv[EVP_MAX_IV_LENGTH];
  53     int ivlen;
  54     const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);
  55
  56     ec = ossl_cms_get0_env_enc_content(cms);
  57     if (ec == NULL)
  58         return NULL;
  59     ris = CMS_get0_RecipientInfos(cms);
  60     if (ris == NULL)
  61         return NULL;
  62
  63     if (wrap_nid <= 0)
  64         wrap_nid = NID_id_alg_PWRI_KEK;
  65
  66     if (pbe_nid <= 0)
  67         pbe_nid = NID_id_pbkdf2;
  68
  69     /* Get from enveloped data */
  70     if (kekciph == NULL)
  71         kekciph = ec->cipher;
  72
  73     if (kekciph == NULL) {
  74         ERR_raise(ERR_LIB_CMS, CMS_R_NO_CIPHER);
  75         return NULL;
  76     }
  77     if (wrap_nid != NID_id_alg_PWRI_KEK) {
  78         ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
  79         return NULL;
  80     }
  81
  82     /* Setup algorithm identifier for cipher */
  83     encalg = X509_ALGOR_new();
  84     if (encalg == NULL) {
  85         ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
  86         goto err;
  87     }
  88     ctx = EVP_CIPHER_CTX_new();
  89     if (ctx == NULL) {
  90         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
  91         goto err;
  92     }
  93
  94     if (EVP_EncryptInit_ex(ctx, kekciph, NULL, NULL, NULL) <= 0) {
  95         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
  96         goto err;
  97     }
  98
  99     ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
 100     if (ivlen < 0) {
 101         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
 102         goto err;
 103     }
 104
 105     if (ivlen > 0) {
 106         if (RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), iv, ivlen, 0) <= 0)
 107             goto err;
 108         if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) <= 0) {
 109             ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
 110             goto err;
 111         }
 112         encalg->parameter = ASN1_TYPE_new();
 113         if (!encalg->parameter) {
 114             ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
 115             goto err;
 116         }
 117         if (EVP_CIPHER_param_to_asn1(ctx, encalg->parameter) <= 0) {
 118             ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 119             goto err;
 120         }
 121     }
 122
 123     encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_get_type(ctx));
 124
 125     EVP_CIPHER_CTX_free(ctx);
 126     ctx = NULL;
 127
 128     /* Initialize recipient info */
 129     ri = M_ASN1_new_of(CMS_RecipientInfo);
 130     if (ri == NULL) {
 131         ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
 132         goto err;
 133     }
 134
 135     ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
 136     if (ri->d.pwri == NULL) {
 137         ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
 138         goto err;
 139     }
 140     ri->type = CMS_RECIPINFO_PASS;
 141
 142     pwri = ri->d.pwri;
 143     pwri->cms_ctx = cms_ctx;
 144     /* Since this is overwritten, free up empty structure already there */
 145     X509_ALGOR_free(pwri->keyEncryptionAlgorithm);
 146     pwri->keyEncryptionAlgorithm = X509_ALGOR_new();
 147     if (pwri->keyEncryptionAlgorithm == NULL) {
 148         ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
 149         goto err;
 150     }
 151     pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
 152     pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
 153     if (pwri->keyEncryptionAlgorithm->parameter == NULL) {
 154         ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
 155         goto err;
 156     }
 157
 158     if (!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),
 159                         &pwri->keyEncryptionAlgorithm->parameter->
 160                         value.sequence)) {
 161         ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
 162         goto err;
 163     }
 164     pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;
 165
 166     X509_ALGOR_free(encalg);
 167     encalg = NULL;
 168
 169     /* Setup PBE algorithm */
 170
 171     pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set(iter, NULL, 0, -1, -1);
 172
 173     if (pwri->keyDerivationAlgorithm == NULL)
 174         goto err;
 175
 176     CMS_RecipientInfo_set0_password(ri, pass, passlen);
 177     pwri->version = 0;
 178
 179     if (!sk_CMS_RecipientInfo_push(ris, ri)) {
 180         ERR_raise(ERR_LIB_CMS, ERR_R_CRYPTO_LIB);
 181         goto err;
 182     }
 183
 184     return ri;
 185
 186  err:
 187     EVP_CIPHER_CTX_free(ctx);
 188     if (ri)
 189         M_ASN1_free_of(ri, CMS_RecipientInfo);
 190     X509_ALGOR_free(encalg);
 191     return NULL;
 192
 193 }
 194
 195 /*
 196  * This is an implementation of the key wrapping mechanism in RFC3211, at
 197  * some point this should go into EVP.
 198  */
 199
 200 static int kek_unwrap_key(unsigned char *out, size_t *outlen,
 201                           const unsigned char *in, size_t inlen,
 202                           EVP_CIPHER_CTX *ctx)
 203 {
 204     size_t blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
 205     unsigned char *tmp;
 206     int outl, rv = 0;
 207
 208     if (blocklen == 0)
 209         return 0;
 210
 211     if (inlen < 2 * blocklen) {
 212         /* too small */
 213         return 0;
 214     }
 215     if (inlen % blocklen) {
 216         /* Invalid size */
 217         return 0;
 218     }
 219     if ((tmp = OPENSSL_malloc(inlen)) == NULL)
 220         return 0;
 221     /* setup IV by decrypting last two blocks */
 222     if (!EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,
 223                            in + inlen - 2 * blocklen, blocklen * 2)
 224         /*
 225          * Do a decrypt of last decrypted block to set IV to correct value
 226          * output it to start of buffer so we don't corrupt decrypted block
 227          * this works because buffer is at least two block lengths long.
 228          */
 229         || !EVP_DecryptUpdate(ctx, tmp, &outl,
 230                               tmp + inlen - blocklen, blocklen)
 231         /* Can now decrypt first n - 1 blocks */
 232         || !EVP_DecryptUpdate(ctx, tmp, &outl, in, inlen - blocklen)
 233
 234         /* Reset IV to original value */
 235         || !EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL)
 236         /* Decrypt again */
 237         || !EVP_DecryptUpdate(ctx, tmp, &outl, tmp, inlen))
 238         goto err;
 239     /* Check check bytes */
 240     if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff) {
 241         /* Check byte failure */
 242         goto err;
 243     }
 244     if (inlen < (size_t)(tmp[0] - 4)) {
 245         /* Invalid length value */
 246         goto err;
 247     }
 248     *outlen = (size_t)tmp[0];
 249     memcpy(out, tmp + 4, *outlen);
 250     rv = 1;
 251  err:
 252     OPENSSL_clear_free(tmp, inlen);
 253     return rv;
 254
 255 }
 256
 257 static int kek_wrap_key(unsigned char *out, size_t *outlen,
 258                         const unsigned char *in, size_t inlen,
 259                         EVP_CIPHER_CTX *ctx, const CMS_CTX *cms_ctx)
 260 {
 261     size_t blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
 262     size_t olen;
 263     int dummy;
 264
 265     if (blocklen == 0)
 266         return 0;
 267
 268     /*
 269      * First decide length of output buffer: need header and round up to
 270      * multiple of block length.
 271      */
 272     olen = (inlen + 4 + blocklen - 1) / blocklen;
 273     olen *= blocklen;
 274     if (olen < 2 * blocklen) {
 275         /* Key too small */
 276         return 0;
 277     }
 278     if (inlen > 0xFF) {
 279         /* Key too large */
 280         return 0;
 281     }
 282     if (out) {
 283         /* Set header */
 284         out[0] = (unsigned char)inlen;
 285         out[1] = in[0] ^ 0xFF;
 286         out[2] = in[1] ^ 0xFF;
 287         out[3] = in[2] ^ 0xFF;
 288         memcpy(out + 4, in, inlen);
 289         /* Add random padding to end */
 290         if (olen > inlen + 4
 291             && RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), out + 4 + inlen,
 292                              olen - 4 - inlen, 0) <= 0)
 293             return 0;
 294         /* Encrypt twice */
 295         if (!EVP_EncryptUpdate(ctx, out, &dummy, out, olen)
 296             || !EVP_EncryptUpdate(ctx, out, &dummy, out, olen))
 297             return 0;
 298     }
 299
 300     *outlen = olen;
 301
 302     return 1;
 303 }
 304
 305 /* Encrypt/Decrypt content key in PWRI recipient info */
 306
 307 int ossl_cms_RecipientInfo_pwri_crypt(const CMS_ContentInfo *cms,
 308                                       CMS_RecipientInfo *ri, int en_de)
 309 {
 310     CMS_EncryptedContentInfo *ec;
 311     CMS_PasswordRecipientInfo *pwri;
 312     int r = 0;
 313     X509_ALGOR *algtmp, *kekalg = NULL;
 314     EVP_CIPHER_CTX *kekctx = NULL;
 315     char name[OSSL_MAX_NAME_SIZE];
 316     EVP_CIPHER *kekcipher;
 317     unsigned char *key = NULL;
 318     size_t keylen;
 319     const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);
 320
 321     ec = ossl_cms_get0_env_enc_content(cms);
 322
 323     pwri = ri->d.pwri;
 324
 325     if (pwri->pass == NULL) {
 326         ERR_raise(ERR_LIB_CMS, CMS_R_NO_PASSWORD);
 327         return 0;
 328     }
 329     algtmp = pwri->keyEncryptionAlgorithm;
 330
 331     if (!algtmp || OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK) {
 332         ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
 333         return 0;
 334     }
 335
 336     kekalg = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),
 337                                        algtmp->parameter);
 338
 339     if (kekalg == NULL) {
 340         ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);
 341         return 0;
 342     }
 343
 344     OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0);
 345     kekcipher = EVP_CIPHER_fetch(ossl_cms_ctx_get0_libctx(cms_ctx), name,
 346                                  ossl_cms_ctx_get0_propq(cms_ctx));
 347
 348     if (kekcipher == NULL) {
 349         ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);
 350         goto err;
 351     }
 352
 353     kekctx = EVP_CIPHER_CTX_new();
 354     if (kekctx == NULL) {
 355         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
 356         goto err;
 357     }
 358     /* Fixup cipher based on AlgorithmIdentifier to set IV etc */
 359     if (!EVP_CipherInit_ex(kekctx, kekcipher, NULL, NULL, NULL, en_de))
 360         goto err;
 361     EVP_CIPHER_CTX_set_padding(kekctx, 0);
 362     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) {
 363         ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 364         goto err;
 365     }
 366
 367     algtmp = pwri->keyDerivationAlgorithm;
 368
 369     /* Finish password based key derivation to setup key in "ctx" */
 370
 371     if (EVP_PBE_CipherInit(algtmp->algorithm,
 372                            (char *)pwri->pass, pwri->passlen,
 373                            algtmp->parameter, kekctx, en_de) < 0) {
 374         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
 375         goto err;
 376     }
 377
 378     /* Finally wrap/unwrap the key */
 379
 380     if (en_de) {
 381
 382         if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
 383             goto err;
 384
 385         key = OPENSSL_malloc(keylen);
 386
 387         if (key == NULL)
 388             goto err;
 389
 390         if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
 391             goto err;
 392         pwri->encryptedKey->data = key;
 393         pwri->encryptedKey->length = keylen;
 394     } else {
 395         key = OPENSSL_malloc(pwri->encryptedKey->length);
 396         if (key == NULL)
 397             goto err;
 398         if (!kek_unwrap_key(key, &keylen,
 399                             pwri->encryptedKey->data,
 400                             pwri->encryptedKey->length, kekctx)) {
 401             ERR_raise(ERR_LIB_CMS, CMS_R_UNWRAP_FAILURE);
 402             goto err;
 403         }
 404
 405         OPENSSL_clear_free(ec->key, ec->keylen);
 406         ec->key = key;
 407         ec->keylen = keylen;
 408
 409     }
 410
 411     r = 1;
 412
 413  err:
 414     EVP_CIPHER_free(kekcipher);
 415     EVP_CIPHER_CTX_free(kekctx);
 416
 417     if (!r)
 418         OPENSSL_free(key);
 419     X509_ALGOR_free(kekalg);
 420
 421     return r;
 422
 423 }