crypto/cms/cms_pwri.c

   1 /*
   2  * Copyright 2009-2020 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 "cms_local.h"
  19 #include "crypto/asn1.h"
  20
  21 DEFINE_STACK_OF(CMS_RecipientInfo)
  22
  23 int CMS_RecipientInfo_set0_password(CMS_RecipientInfo *ri,
  24                                     unsigned char *pass, ossl_ssize_t passlen)
  25 {
  26     CMS_PasswordRecipientInfo *pwri;
  27     if (ri->type != CMS_RECIPINFO_PASS) {
  28         CMSerr(CMS_F_CMS_RECIPIENTINFO_SET0_PASSWORD, CMS_R_NOT_PWRI);
  29         return 0;
  30     }
  31
  32     pwri = ri->d.pwri;
  33     pwri->pass = pass;
  34     if (pass && passlen < 0)
  35         passlen = strlen((char *)pass);
  36     pwri->passlen = passlen;
  37     return 1;
  38 }
  39
  40 CMS_RecipientInfo *CMS_add0_recipient_password(CMS_ContentInfo *cms,
  41                                                int iter, int wrap_nid,
  42                                                int pbe_nid,
  43                                                unsigned char *pass,
  44                                                ossl_ssize_t passlen,
  45                                                const EVP_CIPHER *kekciph)
  46 {
  47     STACK_OF(CMS_RecipientInfo) *ris;
  48     CMS_RecipientInfo *ri = NULL;
  49     CMS_EncryptedContentInfo *ec;
  50     CMS_PasswordRecipientInfo *pwri;
  51     EVP_CIPHER_CTX *ctx = NULL;
  52     X509_ALGOR *encalg = NULL;
  53     unsigned char iv[EVP_MAX_IV_LENGTH];
  54     int ivlen;
  55     const CMS_CTX *cms_ctx = cms_get0_cmsctx(cms);
  56
  57     ec = cms_get0_env_enc_content(cms);
  58     if (ec == NULL)
  59         return NULL;
  60     ris = CMS_get0_RecipientInfos(cms);
  61     if (ris == NULL)
  62         return NULL;
  63
  64     if (wrap_nid <= 0)
  65         wrap_nid = NID_id_alg_PWRI_KEK;
  66
  67     if (pbe_nid <= 0)
  68         pbe_nid = NID_id_pbkdf2;
  69
  70     /* Get from enveloped data */
  71     if (kekciph == NULL)
  72         kekciph = ec->cipher;
  73
  74     if (kekciph == NULL) {
  75         CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, CMS_R_NO_CIPHER);
  76         return NULL;
  77     }
  78     if (wrap_nid != NID_id_alg_PWRI_KEK) {
  79         CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,
  80                CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
  81         return NULL;
  82     }
  83
  84     /* Setup algorithm identifier for cipher */
  85     encalg = X509_ALGOR_new();
  86     if (encalg == NULL) {
  87         goto merr;
  88     }
  89     ctx = EVP_CIPHER_CTX_new();
  90
  91     if (EVP_EncryptInit_ex(ctx, kekciph, NULL, NULL, NULL) <= 0) {
  92         CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_EVP_LIB);
  93         goto err;
  94     }
  95
  96     ivlen = EVP_CIPHER_CTX_iv_length(ctx);
  97
  98     if (ivlen > 0) {
  99         if (RAND_bytes_ex(cms_ctx->libctx, iv, ivlen) <= 0)
 100             goto err;
 101         if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) <= 0) {
 102             CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_EVP_LIB);
 103             goto err;
 104         }
 105         encalg->parameter = ASN1_TYPE_new();
 106         if (!encalg->parameter) {
 107             CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_MALLOC_FAILURE);
 108             goto err;
 109         }
 110         if (EVP_CIPHER_param_to_asn1(ctx, encalg->parameter) <= 0) {
 111             CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,
 112                    CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 113             goto err;
 114         }
 115     }
 116
 117     encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_type(ctx));
 118
 119     EVP_CIPHER_CTX_free(ctx);
 120     ctx = NULL;
 121
 122     /* Initialize recipient info */
 123     ri = M_ASN1_new_of(CMS_RecipientInfo);
 124     if (ri == NULL)
 125         goto merr;
 126
 127     ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
 128     if (ri->d.pwri == NULL)
 129         goto merr;
 130     ri->type = CMS_RECIPINFO_PASS;
 131
 132     pwri = ri->d.pwri;
 133     pwri->cms_ctx = cms_ctx;
 134     /* Since this is overwritten, free up empty structure already there */
 135     X509_ALGOR_free(pwri->keyEncryptionAlgorithm);
 136     pwri->keyEncryptionAlgorithm = X509_ALGOR_new();
 137     if (pwri->keyEncryptionAlgorithm == NULL)
 138         goto merr;
 139     pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
 140     pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
 141     if (pwri->keyEncryptionAlgorithm->parameter == NULL)
 142         goto merr;
 143
 144     if (!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),
 145                         &pwri->keyEncryptionAlgorithm->parameter->
 146                         value.sequence))
 147          goto merr;
 148     pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;
 149
 150     X509_ALGOR_free(encalg);
 151     encalg = NULL;
 152
 153     /* Setup PBE algorithm */
 154
 155     pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set(iter, NULL, 0, -1, -1);
 156
 157     if (pwri->keyDerivationAlgorithm == NULL)
 158         goto err;
 159
 160     CMS_RecipientInfo_set0_password(ri, pass, passlen);
 161     pwri->version = 0;
 162
 163     if (!sk_CMS_RecipientInfo_push(ris, ri))
 164         goto merr;
 165
 166     return ri;
 167
 168  merr:
 169     CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_MALLOC_FAILURE);
 170  err:
 171     EVP_CIPHER_CTX_free(ctx);
 172     if (ri)
 173         M_ASN1_free_of(ri, CMS_RecipientInfo);
 174     X509_ALGOR_free(encalg);
 175     return NULL;
 176
 177 }
 178
 179 /*
 180  * This is an implementation of the key wrapping mechanism in RFC3211, at
 181  * some point this should go into EVP.
 182  */
 183
 184 static int kek_unwrap_key(unsigned char *out, size_t *outlen,
 185                           const unsigned char *in, size_t inlen,
 186                           EVP_CIPHER_CTX *ctx)
 187 {
 188     size_t blocklen = EVP_CIPHER_CTX_block_size(ctx);
 189     unsigned char *tmp;
 190     int outl, rv = 0;
 191     if (inlen < 2 * blocklen) {
 192         /* too small */
 193         return 0;
 194     }
 195     if (inlen % blocklen) {
 196         /* Invalid size */
 197         return 0;
 198     }
 199     if ((tmp = OPENSSL_malloc(inlen)) == NULL) {
 200         CMSerr(CMS_F_KEK_UNWRAP_KEY, ERR_R_MALLOC_FAILURE);
 201         return 0;
 202     }
 203     /* setup IV by decrypting last two blocks */
 204     if (!EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,
 205                            in + inlen - 2 * blocklen, blocklen * 2)
 206         /*
 207          * Do a decrypt of last decrypted block to set IV to correct value
 208          * output it to start of buffer so we don't corrupt decrypted block
 209          * this works because buffer is at least two block lengths long.
 210          */
 211         || !EVP_DecryptUpdate(ctx, tmp, &outl,
 212                               tmp + inlen - blocklen, blocklen)
 213         /* Can now decrypt first n - 1 blocks */
 214         || !EVP_DecryptUpdate(ctx, tmp, &outl, in, inlen - blocklen)
 215
 216         /* Reset IV to original value */
 217         || !EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL)
 218         /* Decrypt again */
 219         || !EVP_DecryptUpdate(ctx, tmp, &outl, tmp, inlen))
 220         goto err;
 221     /* Check check bytes */
 222     if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff) {
 223         /* Check byte failure */
 224         goto err;
 225     }
 226     if (inlen < (size_t)(tmp[0] - 4)) {
 227         /* Invalid length value */
 228         goto err;
 229     }
 230     *outlen = (size_t)tmp[0];
 231     memcpy(out, tmp + 4, *outlen);
 232     rv = 1;
 233  err:
 234     OPENSSL_clear_free(tmp, inlen);
 235     return rv;
 236
 237 }
 238
 239 static int kek_wrap_key(unsigned char *out, size_t *outlen,
 240                         const unsigned char *in, size_t inlen,
 241                         EVP_CIPHER_CTX *ctx, const CMS_CTX *cms_ctx)
 242 {
 243     size_t blocklen = EVP_CIPHER_CTX_block_size(ctx);
 244     size_t olen;
 245     int dummy;
 246     /*
 247      * First decide length of output buffer: need header and round up to
 248      * multiple of block length.
 249      */
 250     olen = (inlen + 4 + blocklen - 1) / blocklen;
 251     olen *= blocklen;
 252     if (olen < 2 * blocklen) {
 253         /* Key too small */
 254         return 0;
 255     }
 256     if (inlen > 0xFF) {
 257         /* Key too large */
 258         return 0;
 259     }
 260     if (out) {
 261         /* Set header */
 262         out[0] = (unsigned char)inlen;
 263         out[1] = in[0] ^ 0xFF;
 264         out[2] = in[1] ^ 0xFF;
 265         out[3] = in[2] ^ 0xFF;
 266         memcpy(out + 4, in, inlen);
 267         /* Add random padding to end */
 268         if (olen > inlen + 4
 269             && RAND_bytes_ex(cms_ctx->libctx, out + 4 + inlen,
 270                              olen - 4 - inlen) <= 0)
 271             return 0;
 272         /* Encrypt twice */
 273         if (!EVP_EncryptUpdate(ctx, out, &dummy, out, olen)
 274             || !EVP_EncryptUpdate(ctx, out, &dummy, out, olen))
 275             return 0;
 276     }
 277
 278     *outlen = olen;
 279
 280     return 1;
 281 }
 282
 283 /* Encrypt/Decrypt content key in PWRI recipient info */
 284
 285 int cms_RecipientInfo_pwri_crypt(const CMS_ContentInfo *cms,
 286                                  CMS_RecipientInfo *ri, int en_de)
 287 {
 288     CMS_EncryptedContentInfo *ec;
 289     CMS_PasswordRecipientInfo *pwri;
 290     int r = 0;
 291     X509_ALGOR *algtmp, *kekalg = NULL;
 292     EVP_CIPHER_CTX *kekctx = NULL;
 293     const char *name;
 294     EVP_CIPHER *kekcipher;
 295     unsigned char *key = NULL;
 296     size_t keylen;
 297     const CMS_CTX *cms_ctx = cms_get0_cmsctx(cms);
 298
 299     ec = cms_get0_env_enc_content(cms);
 300
 301     pwri = ri->d.pwri;
 302
 303     if (pwri->pass == NULL) {
 304         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_NO_PASSWORD);
 305         return 0;
 306     }
 307     algtmp = pwri->keyEncryptionAlgorithm;
 308
 309     if (!algtmp || OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK) {
 310         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
 311                CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
 312         return 0;
 313     }
 314
 315     kekalg = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),
 316                                        algtmp->parameter);
 317
 318     if (kekalg == NULL) {
 319         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
 320                CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);
 321         return 0;
 322     }
 323
 324     name = OBJ_nid2sn(OBJ_obj2nid(kekalg->algorithm));
 325     kekcipher = EVP_CIPHER_fetch(cms_ctx->libctx, name, cms_ctx->propq);
 326
 327     if (kekcipher == NULL) {
 328         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_UNKNOWN_CIPHER);
 329         goto err;
 330     }
 331
 332     kekctx = EVP_CIPHER_CTX_new();
 333     if (kekctx == NULL) {
 334         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_MALLOC_FAILURE);
 335         goto err;
 336     }
 337     /* Fixup cipher based on AlgorithmIdentifier to set IV etc */
 338     if (!EVP_CipherInit_ex(kekctx, kekcipher, NULL, NULL, NULL, en_de))
 339         goto err;
 340     EVP_CIPHER_CTX_set_padding(kekctx, 0);
 341     if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) {
 342         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
 343                CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 344         goto err;
 345     }
 346
 347     algtmp = pwri->keyDerivationAlgorithm;
 348
 349     /* Finish password based key derivation to setup key in "ctx" */
 350
 351     if (EVP_PBE_CipherInit(algtmp->algorithm,
 352                            (char *)pwri->pass, pwri->passlen,
 353                            algtmp->parameter, kekctx, en_de) < 0) {
 354         CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_EVP_LIB);
 355         goto err;
 356     }
 357
 358     /* Finally wrap/unwrap the key */
 359
 360     if (en_de) {
 361
 362         if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
 363             goto err;
 364
 365         key = OPENSSL_malloc(keylen);
 366
 367         if (key == NULL)
 368             goto err;
 369
 370         if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
 371             goto err;
 372         pwri->encryptedKey->data = key;
 373         pwri->encryptedKey->length = keylen;
 374     } else {
 375         key = OPENSSL_malloc(pwri->encryptedKey->length);
 376
 377         if (key == NULL) {
 378             CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_MALLOC_FAILURE);
 379             goto err;
 380         }
 381         if (!kek_unwrap_key(key, &keylen,
 382                             pwri->encryptedKey->data,
 383                             pwri->encryptedKey->length, kekctx)) {
 384             CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_UNWRAP_FAILURE);
 385             goto err;
 386         }
 387
 388         OPENSSL_clear_free(ec->key, ec->keylen);
 389         ec->key = key;
 390         ec->keylen = keylen;
 391
 392     }
 393
 394     r = 1;
 395
 396  err:
 397     EVP_CIPHER_free(kekcipher);
 398     EVP_CIPHER_CTX_free(kekctx);
 399
 400     if (!r)
 401         OPENSSL_free(key);
 402     X509_ALGOR_free(kekalg);
 403
 404     return r;
 405
 406 }