crypto/cms/cms_kari.c

   1 /*
   2  * Copyright 2013-2016 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/aes.h>
  17 #include "cms_lcl.h"
  18 #include "crypto/asn1.h"
  19
  20 /* Key Agreement Recipient Info (KARI) routines */
  21
  22 int CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri,
  23                                     X509_ALGOR **palg,
  24                                     ASN1_OCTET_STRING **pukm)
  25 {
  26     if (ri->type != CMS_RECIPINFO_AGREE) {
  27         CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_ALG,
  28                CMS_R_NOT_KEY_AGREEMENT);
  29         return 0;
  30     }
  31     if (palg)
  32         *palg = ri->d.kari->keyEncryptionAlgorithm;
  33     if (pukm)
  34         *pukm = ri->d.kari->ukm;
  35     return 1;
  36 }
  37
  38 /* Retrieve recipient encrypted keys from a kari */
  39
  40 STACK_OF(CMS_RecipientEncryptedKey)
  41 *CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo *ri)
  42 {
  43     if (ri->type != CMS_RECIPINFO_AGREE) {
  44         CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_REKS,
  45                CMS_R_NOT_KEY_AGREEMENT);
  46         return NULL;
  47     }
  48     return ri->d.kari->recipientEncryptedKeys;
  49 }
  50
  51 int CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri,
  52                                         X509_ALGOR **pubalg,
  53                                         ASN1_BIT_STRING **pubkey,
  54                                         ASN1_OCTET_STRING **keyid,
  55                                         X509_NAME **issuer,
  56                                         ASN1_INTEGER **sno)
  57 {
  58     CMS_OriginatorIdentifierOrKey *oik;
  59     if (ri->type != CMS_RECIPINFO_AGREE) {
  60         CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_ORIG_ID,
  61                CMS_R_NOT_KEY_AGREEMENT);
  62         return 0;
  63     }
  64     oik = ri->d.kari->originator;
  65     if (issuer)
  66         *issuer = NULL;
  67     if (sno)
  68         *sno = NULL;
  69     if (keyid)
  70         *keyid = NULL;
  71     if (pubalg)
  72         *pubalg = NULL;
  73     if (pubkey)
  74         *pubkey = NULL;
  75     if (oik->type == CMS_OIK_ISSUER_SERIAL) {
  76         if (issuer)
  77             *issuer = oik->d.issuerAndSerialNumber->issuer;
  78         if (sno)
  79             *sno = oik->d.issuerAndSerialNumber->serialNumber;
  80     } else if (oik->type == CMS_OIK_KEYIDENTIFIER) {
  81         if (keyid)
  82             *keyid = oik->d.subjectKeyIdentifier;
  83     } else if (oik->type == CMS_OIK_PUBKEY) {
  84         if (pubalg)
  85             *pubalg = oik->d.originatorKey->algorithm;
  86         if (pubkey)
  87             *pubkey = oik->d.originatorKey->publicKey;
  88     } else
  89         return 0;
  90     return 1;
  91 }
  92
  93 int CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo *ri, X509 *cert)
  94 {
  95     CMS_OriginatorIdentifierOrKey *oik;
  96     if (ri->type != CMS_RECIPINFO_AGREE) {
  97         CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_ORIG_ID_CMP,
  98                CMS_R_NOT_KEY_AGREEMENT);
  99         return -2;
 100     }
 101     oik = ri->d.kari->originator;
 102     if (oik->type == CMS_OIK_ISSUER_SERIAL)
 103         return cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);
 104     else if (oik->type == CMS_OIK_KEYIDENTIFIER)
 105         return cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);
 106     return -1;
 107 }
 108
 109 int CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,
 110                                       ASN1_OCTET_STRING **keyid,
 111                                       ASN1_GENERALIZEDTIME **tm,
 112                                       CMS_OtherKeyAttribute **other,
 113                                       X509_NAME **issuer, ASN1_INTEGER **sno)
 114 {
 115     CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
 116     if (rid->type == CMS_REK_ISSUER_SERIAL) {
 117         if (issuer)
 118             *issuer = rid->d.issuerAndSerialNumber->issuer;
 119         if (sno)
 120             *sno = rid->d.issuerAndSerialNumber->serialNumber;
 121         if (keyid)
 122             *keyid = NULL;
 123         if (tm)
 124             *tm = NULL;
 125         if (other)
 126             *other = NULL;
 127     } else if (rid->type == CMS_REK_KEYIDENTIFIER) {
 128         if (keyid)
 129             *keyid = rid->d.rKeyId->subjectKeyIdentifier;
 130         if (tm)
 131             *tm = rid->d.rKeyId->date;
 132         if (other)
 133             *other = rid->d.rKeyId->other;
 134         if (issuer)
 135             *issuer = NULL;
 136         if (sno)
 137             *sno = NULL;
 138     } else
 139         return 0;
 140     return 1;
 141 }
 142
 143 int CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek,
 144                                        X509 *cert)
 145 {
 146     CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
 147     if (rid->type == CMS_REK_ISSUER_SERIAL)
 148         return cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);
 149     else if (rid->type == CMS_REK_KEYIDENTIFIER)
 150         return cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier, cert);
 151     else
 152         return -1;
 153 }
 154
 155 int CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pk)
 156 {
 157     EVP_PKEY_CTX *pctx;
 158     CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;
 159
 160     EVP_PKEY_CTX_free(kari->pctx);
 161     kari->pctx = NULL;
 162     if (!pk)
 163         return 1;
 164     pctx = EVP_PKEY_CTX_new(pk, NULL);
 165     if (!pctx || !EVP_PKEY_derive_init(pctx))
 166         goto err;
 167     kari->pctx = pctx;
 168     return 1;
 169  err:
 170     EVP_PKEY_CTX_free(pctx);
 171     return 0;
 172 }
 173
 174 EVP_CIPHER_CTX *CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri)
 175 {
 176     if (ri->type == CMS_RECIPINFO_AGREE)
 177         return ri->d.kari->ctx;
 178     return NULL;
 179 }
 180
 181 /*
 182  * Derive KEK and decrypt/encrypt with it to produce either the original CEK
 183  * or the encrypted CEK.
 184  */
 185
 186 static int cms_kek_cipher(unsigned char **pout, size_t *poutlen,
 187                           const unsigned char *in, size_t inlen,
 188                           CMS_KeyAgreeRecipientInfo *kari, int enc)
 189 {
 190     /* Key encryption key */
 191     unsigned char kek[EVP_MAX_KEY_LENGTH];
 192     size_t keklen;
 193     int rv = 0;
 194     unsigned char *out = NULL;
 195     int outlen;
 196     keklen = EVP_CIPHER_CTX_key_length(kari->ctx);
 197     if (keklen > EVP_MAX_KEY_LENGTH)
 198         return 0;
 199     /* Derive KEK */
 200     if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)
 201         goto err;
 202     /* Set KEK in context */
 203     if (!EVP_CipherInit_ex(kari->ctx, NULL, NULL, kek, NULL, enc))
 204         goto err;
 205     /* obtain output length of ciphered key */
 206     if (!EVP_CipherUpdate(kari->ctx, NULL, &outlen, in, inlen))
 207         goto err;
 208     out = OPENSSL_malloc(outlen);
 209     if (out == NULL)
 210         goto err;
 211     if (!EVP_CipherUpdate(kari->ctx, out, &outlen, in, inlen))
 212         goto err;
 213     *pout = out;
 214     *poutlen = (size_t)outlen;
 215     rv = 1;
 216
 217  err:
 218     OPENSSL_cleanse(kek, keklen);
 219     if (!rv)
 220         OPENSSL_free(out);
 221     EVP_CIPHER_CTX_reset(kari->ctx);
 222     /* FIXME: WHY IS kari->pctx freed here?  /RL */
 223     EVP_PKEY_CTX_free(kari->pctx);
 224     kari->pctx = NULL;
 225     return rv;
 226 }
 227
 228 int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms,
 229                                    CMS_RecipientInfo *ri,
 230                                    CMS_RecipientEncryptedKey *rek)
 231 {
 232     int rv = 0;
 233     unsigned char *enckey = NULL, *cek = NULL;
 234     size_t enckeylen;
 235     size_t ceklen;
 236     CMS_EncryptedContentInfo *ec;
 237     enckeylen = rek->encryptedKey->length;
 238     enckey = rek->encryptedKey->data;
 239     /* Setup all parameters to derive KEK */
 240     if (!cms_env_asn1_ctrl(ri, 1))
 241         goto err;
 242     /* Attempt to decrypt CEK */
 243     if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))
 244         goto err;
 245     ec = cms->d.envelopedData->encryptedContentInfo;
 246     OPENSSL_clear_free(ec->key, ec->keylen);
 247     ec->key = cek;
 248     ec->keylen = ceklen;
 249     cek = NULL;
 250     rv = 1;
 251  err:
 252     OPENSSL_free(cek);
 253     return rv;
 254 }
 255
 256 /* Create ephemeral key and initialise context based on it */
 257 static int cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari,
 258                                          EVP_PKEY *pk)
 259 {
 260     EVP_PKEY_CTX *pctx = NULL;
 261     EVP_PKEY *ekey = NULL;
 262     int rv = 0;
 263     pctx = EVP_PKEY_CTX_new(pk, NULL);
 264     if (!pctx)
 265         goto err;
 266     if (EVP_PKEY_keygen_init(pctx) <= 0)
 267         goto err;
 268     if (EVP_PKEY_keygen(pctx, &ekey) <= 0)
 269         goto err;
 270     EVP_PKEY_CTX_free(pctx);
 271     pctx = EVP_PKEY_CTX_new(ekey, NULL);
 272     if (!pctx)
 273         goto err;
 274     if (EVP_PKEY_derive_init(pctx) <= 0)
 275         goto err;
 276     kari->pctx = pctx;
 277     rv = 1;
 278  err:
 279     if (!rv)
 280         EVP_PKEY_CTX_free(pctx);
 281     EVP_PKEY_free(ekey);
 282     return rv;
 283 }
 284
 285 /* Initialise a kari based on passed certificate and key */
 286
 287 int cms_RecipientInfo_kari_init(CMS_RecipientInfo *ri, X509 *recip,
 288                                 EVP_PKEY *pk, unsigned int flags)
 289 {
 290     CMS_KeyAgreeRecipientInfo *kari;
 291     CMS_RecipientEncryptedKey *rek = NULL;
 292
 293     ri->d.kari = M_ASN1_new_of(CMS_KeyAgreeRecipientInfo);
 294     if (!ri->d.kari)
 295         return 0;
 296     ri->type = CMS_RECIPINFO_AGREE;
 297
 298     kari = ri->d.kari;
 299     kari->version = 3;
 300
 301     rek = M_ASN1_new_of(CMS_RecipientEncryptedKey);
 302     if (rek == NULL)
 303         return 0;
 304
 305     if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {
 306         M_ASN1_free_of(rek, CMS_RecipientEncryptedKey);
 307         return 0;
 308     }
 309
 310     if (flags & CMS_USE_KEYID) {
 311         rek->rid->type = CMS_REK_KEYIDENTIFIER;
 312         rek->rid->d.rKeyId = M_ASN1_new_of(CMS_RecipientKeyIdentifier);
 313         if (rek->rid->d.rKeyId == NULL)
 314             return 0;
 315         if (!cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))
 316             return 0;
 317     } else {
 318         rek->rid->type = CMS_REK_ISSUER_SERIAL;
 319         if (!cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))
 320             return 0;
 321     }
 322
 323     /* Create ephemeral key */
 324     if (!cms_kari_create_ephemeral_key(kari, pk))
 325         return 0;
 326
 327     EVP_PKEY_up_ref(pk);
 328     rek->pkey = pk;
 329     return 1;
 330 }
 331
 332 static int cms_wrap_init(CMS_KeyAgreeRecipientInfo *kari,
 333                          const EVP_CIPHER *cipher)
 334 {
 335     EVP_CIPHER_CTX *ctx = kari->ctx;
 336     const EVP_CIPHER *kekcipher;
 337     int keylen = EVP_CIPHER_key_length(cipher);
 338     /* If a suitable wrap algorithm is already set nothing to do */
 339     kekcipher = EVP_CIPHER_CTX_cipher(ctx);
 340
 341     if (kekcipher) {
 342         if (EVP_CIPHER_CTX_mode(ctx) != EVP_CIPH_WRAP_MODE)
 343             return 0;
 344         return 1;
 345     }
 346     /*
 347      * Pick a cipher based on content encryption cipher. If it is DES3 use
 348      * DES3 wrap otherwise use AES wrap similar to key size.
 349      */
 350 #ifndef OPENSSL_NO_DES
 351     if (EVP_CIPHER_type(cipher) == NID_des_ede3_cbc)
 352         kekcipher = EVP_des_ede3_wrap();
 353     else
 354 #endif
 355     if (keylen <= 16)
 356         kekcipher = EVP_aes_128_wrap();
 357     else if (keylen <= 24)
 358         kekcipher = EVP_aes_192_wrap();
 359     else
 360         kekcipher = EVP_aes_256_wrap();
 361     return EVP_EncryptInit_ex(ctx, kekcipher, NULL, NULL, NULL);
 362 }
 363
 364 /* Encrypt content key in key agreement recipient info */
 365
 366 int cms_RecipientInfo_kari_encrypt(const CMS_ContentInfo *cms,
 367                                    CMS_RecipientInfo *ri)
 368 {
 369     CMS_KeyAgreeRecipientInfo *kari;
 370     CMS_EncryptedContentInfo *ec;
 371     CMS_RecipientEncryptedKey *rek;
 372     STACK_OF(CMS_RecipientEncryptedKey) *reks;
 373     int i;
 374
 375     if (ri->type != CMS_RECIPINFO_AGREE) {
 376         CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_ENCRYPT, CMS_R_NOT_KEY_AGREEMENT);
 377         return 0;
 378     }
 379     kari = ri->d.kari;
 380     reks = kari->recipientEncryptedKeys;
 381     ec = cms->d.envelopedData->encryptedContentInfo;
 382     /* Initialise wrap algorithm parameters */
 383     if (!cms_wrap_init(kari, ec->cipher))
 384         return 0;
 385     /*
 386      * If no originator key set up initialise for ephemeral key the public key
 387      * ASN1 structure will set the actual public key value.
 388      */
 389     if (kari->originator->type == -1) {
 390         CMS_OriginatorIdentifierOrKey *oik = kari->originator;
 391         oik->type = CMS_OIK_PUBKEY;
 392         oik->d.originatorKey = M_ASN1_new_of(CMS_OriginatorPublicKey);
 393         if (!oik->d.originatorKey)
 394             return 0;
 395     }
 396     /* Initialise KDF algorithm */
 397     if (!cms_env_asn1_ctrl(ri, 0))
 398         return 0;
 399     /* For each rek, derive KEK, encrypt CEK */
 400     for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {
 401         unsigned char *enckey;
 402         size_t enckeylen;
 403         rek = sk_CMS_RecipientEncryptedKey_value(reks, i);
 404         if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)
 405             return 0;
 406         if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,
 407                             kari, 1))
 408             return 0;
 409         ASN1_STRING_set0(rek->encryptedKey, enckey, enckeylen);
 410     }
 411
 412     return 1;
 413
 414 }