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         goto merr;
  86     }
  87     ctx = EVP_CIPHER_CTX_new();
  88
  89     if (EVP_EncryptInit_ex(ctx, kekciph, NULL, NULL, NULL) <= 0) {
  90         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
  91         goto err;
  92     }
  93
  94     ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
  95
  96     if (ivlen > 0) {
  97         if (RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), iv, ivlen, 0) <= 0)
  98             goto err;
  99         if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) <= 0) {
 100             ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
 101             goto err;
 102         }
 103         encalg->parameter = ASN1_TYPE_new();
 104         if (!encalg->parameter) {
 105             ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 106             goto err;
 107         }
 108         if (EVP_CIPHER_param_to_asn1(ctx, encalg->parameter) <= 0) {
 109             ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 110             goto err;
 111         }
 112     }
 113
 114     encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_get_type(ctx));
 115
 116     EVP_CIPHER_CTX_free(ctx);
 117     ctx = NULL;
 118
 119     /* Initialize recipient info */
 120     ri = M_ASN1_new_of(CMS_RecipientInfo);
 121     if (ri == NULL)
 122         goto merr;
 123
 124     ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
 125     if (ri->d.pwri == NULL)
 126         goto merr;
 127     ri->type = CMS_RECIPINFO_PASS;
 128
 129     pwri = ri->d.pwri;
 130     pwri->cms_ctx = cms_ctx;
 131     /* Since this is overwritten, free up empty structure already there */
 132     X509_ALGOR_free(pwri->keyEncryptionAlgorithm);
 133     pwri->keyEncryptionAlgorithm = X509_ALGOR_new();
 134     if (pwri->keyEncryptionAlgorithm == NULL)
 135         goto merr;
 136     pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
 137     pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
 138     if (pwri->keyEncryptionAlgorithm->parameter == NULL)
 139         goto merr;
 140
 141     if (!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),
 142                         &pwri->keyEncryptionAlgorithm->parameter->
 143                         value.sequence))
 144          goto merr;
 145     pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;
 146
 147     X509_ALGOR_free(encalg);
 148     encalg = NULL;
 149
 150     /* Setup PBE algorithm */
 151
 152     pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set(iter, NULL, 0, -1, -1);
 153
 154     if (pwri->keyDerivationAlgorithm == NULL)
 155         goto err;
 156
 157     CMS_RecipientInfo_set0_password(ri, pass, passlen);
 158     pwri->version = 0;
 159
 160     if (!sk_CMS_RecipientInfo_push(ris, ri))
 161         goto merr;
 162
 163     return ri;
 164
 165  merr:
 166     ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 167  err:
 168     EVP_CIPHER_CTX_free(ctx);
 169     if (ri)
 170         M_ASN1_free_of(ri, CMS_RecipientInfo);
 171     X509_ALGOR_free(encalg);
 172     return NULL;
 173
 174 }
 175
 176 /*
 177  * This is an implementation of the key wrapping mechanism in RFC3211, at
 178  * some point this should go into EVP.
 179  */
 180
 181 static int kek_unwrap_key(unsigned char *out, size_t *outlen,
 182                           const unsigned char *in, size_t inlen,
 183                           EVP_CIPHER_CTX *ctx)
 184 {
 185     size_t blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
 186     unsigned char *tmp;
 187     int outl, rv = 0;
 188     if (inlen < 2 * blocklen) {
 189         /* too small */
 190         return 0;
 191     }
 192     if (inlen % blocklen) {
 193         /* Invalid size */
 194         return 0;
 195     }
 196     if ((tmp = OPENSSL_malloc(inlen)) == NULL) {
 197         ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 198         return 0;
 199     }
 200     /* setup IV by decrypting last two blocks */
 201     if (!EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,
 202                            in + inlen - 2 * blocklen, blocklen * 2)
 203         /*
 204          * Do a decrypt of last decrypted block to set IV to correct value
 205          * output it to start of buffer so we don't corrupt decrypted block
 206          * this works because buffer is at least two block lengths long.
 207          */
 208         || !EVP_DecryptUpdate(ctx, tmp, &outl,
 209                               tmp + inlen - blocklen, blocklen)
 210         /* Can now decrypt first n - 1 blocks */
 211         || !EVP_DecryptUpdate(ctx, tmp, &outl, in, inlen - blocklen)
 212
 213         /* Reset IV to original value */
 214         || !EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL)
 215         /* Decrypt again */
 216         || !EVP_DecryptUpdate(ctx, tmp, &outl, tmp, inlen))
 217         goto err;
 218     /* Check check bytes */
 219     if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff) {
 220         /* Check byte failure */
 221         goto err;
 222     }
 223     if (inlen < (size_t)(tmp[0] - 4)) {
 224         /* Invalid length value */
 225         goto err;
 226     }
 227     *outlen = (size_t)tmp[0];
 228     memcpy(out, tmp + 4, *outlen);
 229     rv = 1;
 230  err:
 231     OPENSSL_clear_free(tmp, inlen);
 232     return rv;
 233
 234 }
 235
 236 static int kek_wrap_key(unsigned char *out, size_t *outlen,
 237                         const unsigned char *in, size_t inlen,
 238                         EVP_CIPHER_CTX *ctx, const CMS_CTX *cms_ctx)
 239 {
 240     size_t blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
 241     size_t olen;
 242     int dummy;
 243     /*
 244      * First decide length of output buffer: need header and round up to
 245      * multiple of block length.
 246      */
 247     olen = (inlen + 4 + blocklen - 1) / blocklen;
 248     olen *= blocklen;
 249     if (olen < 2 * blocklen) {
 250         /* Key too small */
 251         return 0;
 252     }
 253     if (inlen > 0xFF) {
 254         /* Key too large */
 255         return 0;
 256     }
 257     if (out) {
 258         /* Set header */
 259         out[0] = (unsigned char)inlen;
 260         out[1] = in[0] ^ 0xFF;
 261         out[2] = in[1] ^ 0xFF;
 262         out[3] = in[2] ^ 0xFF;
 263         memcpy(out + 4, in, inlen);
 264         /* Add random padding to end */
 265         if (olen > inlen + 4
 266             && RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), out + 4 + inlen,
 267                              olen - 4 - inlen, 0) <= 0)
 268             return 0;
 269         /* Encrypt twice */
 270         if (!EVP_EncryptUpdate(ctx, out, &dummy, out, olen)
 271             || !EVP_EncryptUpdate(ctx, out, &dummy, out, olen))
 272             return 0;
 273     }
 274
 275     *outlen = olen;
 276
 277     return 1;
 278 }
 279
 280 /* Encrypt/Decrypt content key in PWRI recipient info */
 281
 282 int ossl_cms_RecipientInfo_pwri_crypt(const CMS_ContentInfo *cms,
 283                                       CMS_RecipientInfo *ri, int en_de)
 284 {
 285     CMS_EncryptedContentInfo *ec;
 286     CMS_PasswordRecipientInfo *pwri;
 287     int r = 0;
 288     X509_ALGOR *algtmp, *kekalg = NULL;
 289     EVP_CIPHER_CTX *kekctx = NULL;
 290     char name[OSSL_MAX_NAME_SIZE];
 291     EVP_CIPHER *kekcipher;
 292     unsigned char *key = NULL;
 293     size_t keylen;
 294     const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);
 295
 296     ec = ossl_cms_get0_env_enc_content(cms);
 297
 298     pwri = ri->d.pwri;
 299
 300     if (pwri->pass == NULL) {
 301         ERR_raise(ERR_LIB_CMS, CMS_R_NO_PASSWORD);
 302         return 0;
 303     }
 304     algtmp = pwri->keyEncryptionAlgorithm;
 305
 306     if (!algtmp || OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK) {
 307         ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
 308         return 0;
 309     }
 310
 311     kekalg = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),
 312                                        algtmp->parameter);
 313
 314     if (kekalg == NULL) {
 315         ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);
 316         return 0;
 317     }
 318
 319     OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0);
 320     kekcipher = EVP_CIPHER_fetch(ossl_cms_ctx_get0_libctx(cms_ctx), name,
 321                                  ossl_cms_ctx_get0_propq(cms_ctx));
 322
 323     if (kekcipher == NULL) {
 324         ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);
 325         goto err;
 326     }
 327
 328     kekctx = EVP_CIPHER_CTX_new();
 329     if (kekctx == NULL) {
 330         ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 331         goto err;
 332     }
 333     /* Fixup cipher based on AlgorithmIdentifier to set IV etc */
 334     if (!EVP_CipherInit_ex(kekctx, kekcipher, NULL, NULL, NULL, en_de))
 335         goto err;
 336     EVP_CIPHER_CTX_set_padding(kekctx, 0);
 337     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) {
 338         ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 339         goto err;
 340     }
 341
 342     algtmp = pwri->keyDerivationAlgorithm;
 343
 344     /* Finish password based key derivation to setup key in "ctx" */
 345
 346     if (EVP_PBE_CipherInit(algtmp->algorithm,
 347                            (char *)pwri->pass, pwri->passlen,
 348                            algtmp->parameter, kekctx, en_de) < 0) {
 349         ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
 350         goto err;
 351     }
 352
 353     /* Finally wrap/unwrap the key */
 354
 355     if (en_de) {
 356
 357         if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
 358             goto err;
 359
 360         key = OPENSSL_malloc(keylen);
 361
 362         if (key == NULL)
 363             goto err;
 364
 365         if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
 366             goto err;
 367         pwri->encryptedKey->data = key;
 368         pwri->encryptedKey->length = keylen;
 369     } else {
 370         key = OPENSSL_malloc(pwri->encryptedKey->length);
 371
 372         if (key == NULL) {
 373             ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 374             goto err;
 375         }
 376         if (!kek_unwrap_key(key, &keylen,
 377                             pwri->encryptedKey->data,
 378                             pwri->encryptedKey->length, kekctx)) {
 379             ERR_raise(ERR_LIB_CMS, CMS_R_UNWRAP_FAILURE);
 380             goto err;
 381         }
 382
 383         OPENSSL_clear_free(ec->key, ec->keylen);
 384         ec->key = key;
 385         ec->keylen = keylen;
 386
 387     }
 388
 389     r = 1;
 390
 391  err:
 392     EVP_CIPHER_free(kekcipher);
 393     EVP_CIPHER_CTX_free(kekctx);
 394
 395     if (!r)
 396         OPENSSL_free(key);
 397     X509_ALGOR_free(kekalg);
 398
 399     return r;
 400
 401 }