crypto/cms/cms_enc.c

   1 /*
   2  * Copyright 2008-2020 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 "crypto/evp.h"
  18 #include "cms_local.h"
  19
  20 /* CMS EncryptedData Utilities */
  21
  22 /* Return BIO based on EncryptedContentInfo and key */
  23
  24 BIO *cms_EncryptedContent_init_bio(CMS_EncryptedContentInfo *ec,
  25                                    const CMS_CTX *cms_ctx)
  26 {
  27     BIO *b;
  28     EVP_CIPHER_CTX *ctx;
  29     EVP_CIPHER *fetched_ciph = NULL;
  30     const EVP_CIPHER *cipher = NULL;
  31     X509_ALGOR *calg = ec->contentEncryptionAlgorithm;
  32     evp_cipher_aead_asn1_params aparams;
  33     unsigned char iv[EVP_MAX_IV_LENGTH], *piv = NULL;
  34     unsigned char *tkey = NULL;
  35     int len;
  36     int ivlen = 0;
  37     size_t tkeylen = 0;
  38     int ok = 0;
  39     int enc, keep_key = 0;
  40
  41     enc = ec->cipher ? 1 : 0;
  42
  43     b = BIO_new(BIO_f_cipher());
  44     if (b == NULL) {
  45         ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
  46         return NULL;
  47     }
  48
  49     BIO_get_cipher_ctx(b, &ctx);
  50
  51     (void)ERR_set_mark();
  52     if (enc) {
  53         cipher = ec->cipher;
  54         /*
  55          * If not keeping key set cipher to NULL so subsequent calls decrypt.
  56          */
  57         if (ec->key != NULL)
  58             ec->cipher = NULL;
  59     } else {
  60         cipher = EVP_get_cipherbyobj(calg->algorithm);
  61     }
  62     if (cipher != NULL) {
  63         fetched_ciph = EVP_CIPHER_fetch(cms_ctx->libctx, EVP_CIPHER_name(cipher),
  64                                         cms_ctx->propq);
  65         if (fetched_ciph != NULL)
  66             cipher = fetched_ciph;
  67     }
  68     if (cipher == NULL) {
  69         (void)ERR_clear_last_mark();
  70         ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);
  71         goto err;
  72     }
  73     (void)ERR_pop_to_mark();
  74
  75     if (EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, enc) <= 0) {
  76         ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_INITIALISATION_ERROR);
  77         goto err;
  78     }
  79
  80     if (enc) {
  81         calg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_type(ctx));
  82         /* Generate a random IV if we need one */
  83         ivlen = EVP_CIPHER_CTX_iv_length(ctx);
  84         if (ivlen > 0) {
  85             if (RAND_bytes_ex(cms_ctx->libctx, iv, ivlen) <= 0)
  86                 goto err;
  87             piv = iv;
  88         }
  89     } else {
  90         if (evp_cipher_asn1_to_param_ex(ctx, calg->parameter, &aparams) <= 0) {
  91             ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
  92             goto err;
  93         }
  94         if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
  95             piv = aparams.iv;
  96             if (ec->taglen > 0
  97                     && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG,
  98                                            ec->taglen, ec->tag) <= 0) {
  99                 ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_AEAD_SET_TAG_ERROR);
 100                 goto err;
 101             }
 102         }
 103     }
 104     len = EVP_CIPHER_CTX_key_length(ctx);
 105     if (len <= 0)
 106         goto err;
 107     tkeylen = (size_t)len;
 108
 109     /* Generate random session key */
 110     if (!enc || !ec->key) {
 111         tkey = OPENSSL_malloc(tkeylen);
 112         if (tkey == NULL) {
 113             ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 114             goto err;
 115         }
 116         if (EVP_CIPHER_CTX_rand_key(ctx, tkey) <= 0)
 117             goto err;
 118     }
 119
 120     if (!ec->key) {
 121         ec->key = tkey;
 122         ec->keylen = tkeylen;
 123         tkey = NULL;
 124         if (enc)
 125             keep_key = 1;
 126         else
 127             ERR_clear_error();
 128
 129     }
 130
 131     if (ec->keylen != tkeylen) {
 132         /* If necessary set key length */
 133         if (EVP_CIPHER_CTX_set_key_length(ctx, ec->keylen) <= 0) {
 134             /*
 135              * Only reveal failure if debugging so we don't leak information
 136              * which may be useful in MMA.
 137              */
 138             if (enc || ec->debug) {
 139                 ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_LENGTH);
 140                 goto err;
 141             } else {
 142                 /* Use random key */
 143                 OPENSSL_clear_free(ec->key, ec->keylen);
 144                 ec->key = tkey;
 145                 ec->keylen = tkeylen;
 146                 tkey = NULL;
 147                 ERR_clear_error();
 148             }
 149         }
 150     }
 151
 152     if (EVP_CipherInit_ex(ctx, NULL, NULL, ec->key, piv, enc) <= 0) {
 153         ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_INITIALISATION_ERROR);
 154         goto err;
 155     }
 156     if (enc) {
 157         calg->parameter = ASN1_TYPE_new();
 158         if (calg->parameter == NULL) {
 159             ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 160             goto err;
 161         }
 162         if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
 163             memcpy(aparams.iv, piv, ivlen);
 164             aparams.iv_len = ivlen;
 165             aparams.tag_len = EVP_CIPHER_CTX_tag_length(ctx);
 166             if (aparams.tag_len <= 0)
 167                 goto err;
 168         }
 169
 170         if (evp_cipher_param_to_asn1_ex(ctx, calg->parameter, &aparams) <= 0) {
 171             ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
 172             goto err;
 173         }
 174         /* If parameter type not set omit parameter */
 175         if (calg->parameter->type == V_ASN1_UNDEF) {
 176             ASN1_TYPE_free(calg->parameter);
 177             calg->parameter = NULL;
 178         }
 179     }
 180     ok = 1;
 181
 182  err:
 183     EVP_CIPHER_free(fetched_ciph);
 184     if (!keep_key || !ok) {
 185         OPENSSL_clear_free(ec->key, ec->keylen);
 186         ec->key = NULL;
 187     }
 188     OPENSSL_clear_free(tkey, tkeylen);
 189     if (ok)
 190         return b;
 191     BIO_free(b);
 192     return NULL;
 193 }
 194
 195 int cms_EncryptedContent_init(CMS_EncryptedContentInfo *ec,
 196                               const EVP_CIPHER *cipher,
 197                               const unsigned char *key, size_t keylen,
 198                               const CMS_CTX *cms_ctx)
 199 {
 200     ec->cipher = cipher;
 201     if (key) {
 202         if ((ec->key = OPENSSL_malloc(keylen)) == NULL) {
 203             ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 204             return 0;
 205         }
 206         memcpy(ec->key, key, keylen);
 207     }
 208     ec->keylen = keylen;
 209     if (cipher != NULL)
 210         ec->contentType = OBJ_nid2obj(NID_pkcs7_data);
 211     return 1;
 212 }
 213
 214 int CMS_EncryptedData_set1_key(CMS_ContentInfo *cms, const EVP_CIPHER *ciph,
 215                                const unsigned char *key, size_t keylen)
 216 {
 217     CMS_EncryptedContentInfo *ec;
 218
 219     if (!key || !keylen) {
 220         ERR_raise(ERR_LIB_CMS, CMS_R_NO_KEY);
 221         return 0;
 222     }
 223     if (ciph) {
 224         cms->d.encryptedData = M_ASN1_new_of(CMS_EncryptedData);
 225         if (!cms->d.encryptedData) {
 226             ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
 227             return 0;
 228         }
 229         cms->contentType = OBJ_nid2obj(NID_pkcs7_encrypted);
 230         cms->d.encryptedData->version = 0;
 231     } else if (OBJ_obj2nid(cms->contentType) != NID_pkcs7_encrypted) {
 232         ERR_raise(ERR_LIB_CMS, CMS_R_NOT_ENCRYPTED_DATA);
 233         return 0;
 234     }
 235     ec = cms->d.encryptedData->encryptedContentInfo;
 236     return cms_EncryptedContent_init(ec, ciph, key, keylen, cms_get0_cmsctx(cms));
 237 }
 238
 239 BIO *cms_EncryptedData_init_bio(const CMS_ContentInfo *cms)
 240 {
 241     CMS_EncryptedData *enc = cms->d.encryptedData;
 242     if (enc->encryptedContentInfo->cipher && enc->unprotectedAttrs)
 243         enc->version = 2;
 244     return cms_EncryptedContent_init_bio(enc->encryptedContentInfo,
 245                                          cms_get0_cmsctx(cms));
 246 }