crypto/cipher-nettle.c

   1 /*
   2  * QEMU Crypto cipher nettle algorithms
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include <nettle/nettle-types.h>
  23 #include <nettle/aes.h>
  24 #include <nettle/des.h>
  25 #include <nettle/cbc.h>
  26 #include <nettle/cast128.h>
  27
  28 #if CONFIG_NETTLE_VERSION_MAJOR < 3
  29 typedef nettle_crypt_func nettle_cipher_func;
  30
  31 typedef void *       cipher_ctx_t;
  32 typedef unsigned     cipher_length_t;
  33 #else
  34 typedef const void * cipher_ctx_t;
  35 typedef size_t       cipher_length_t;
  36 #endif
  37
  38 static nettle_cipher_func aes_encrypt_wrapper;
  39 static nettle_cipher_func aes_decrypt_wrapper;
  40 static nettle_cipher_func des_encrypt_wrapper;
  41 static nettle_cipher_func des_decrypt_wrapper;
  42
  43 static void aes_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  44                                 uint8_t *dst, const uint8_t *src)
  45 {
  46     aes_encrypt(ctx, length, dst, src);
  47 }
  48
  49 static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  50                                 uint8_t *dst, const uint8_t *src)
  51 {
  52     aes_decrypt(ctx, length, dst, src);
  53 }
  54
  55 static void des_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  56                                 uint8_t *dst, const uint8_t *src)
  57 {
  58     des_encrypt(ctx, length, dst, src);
  59 }
  60
  61 static void des_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  62                                 uint8_t *dst, const uint8_t *src)
  63 {
  64     des_decrypt(ctx, length, dst, src);
  65 }
  66
  67 static void cast128_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  68                                     uint8_t *dst, const uint8_t *src)
  69 {
  70     cast128_encrypt(ctx, length, dst, src);
  71 }
  72
  73 static void cast128_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  74                                     uint8_t *dst, const uint8_t *src)
  75 {
  76     cast128_decrypt(ctx, length, dst, src);
  77 }
  78
  79 typedef struct QCryptoCipherNettle QCryptoCipherNettle;
  80 struct QCryptoCipherNettle {
  81     void *ctx_encrypt;
  82     void *ctx_decrypt;
  83     nettle_cipher_func *alg_encrypt;
  84     nettle_cipher_func *alg_decrypt;
  85     uint8_t *iv;
  86     size_t blocksize;
  87 };
  88
  89 bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
  90 {
  91     switch (alg) {
  92     case QCRYPTO_CIPHER_ALG_DES_RFB:
  93     case QCRYPTO_CIPHER_ALG_AES_128:
  94     case QCRYPTO_CIPHER_ALG_AES_192:
  95     case QCRYPTO_CIPHER_ALG_AES_256:
  96     case QCRYPTO_CIPHER_ALG_CAST5_128:
  97         return true;
  98     default:
  99         return false;
 100     }
 101 }
 102
 103
 104 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 105                                   QCryptoCipherMode mode,
 106                                   const uint8_t *key, size_t nkey,
 107                                   Error **errp)
 108 {
 109     QCryptoCipher *cipher;
 110     QCryptoCipherNettle *ctx;
 111     uint8_t *rfbkey;
 112
 113     switch (mode) {
 114     case QCRYPTO_CIPHER_MODE_ECB:
 115     case QCRYPTO_CIPHER_MODE_CBC:
 116         break;
 117     default:
 118         error_setg(errp, "Unsupported cipher mode %d", mode);
 119         return NULL;
 120     }
 121
 122     if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
 123         return NULL;
 124     }
 125
 126     cipher = g_new0(QCryptoCipher, 1);
 127     cipher->alg = alg;
 128     cipher->mode = mode;
 129
 130     ctx = g_new0(QCryptoCipherNettle, 1);
 131
 132     switch (alg) {
 133     case QCRYPTO_CIPHER_ALG_DES_RFB:
 134         ctx->ctx_encrypt = g_new0(struct des_ctx, 1);
 135         ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
 136         rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
 137         des_set_key(ctx->ctx_encrypt, rfbkey);
 138         g_free(rfbkey);
 139
 140         ctx->alg_encrypt = des_encrypt_wrapper;
 141         ctx->alg_decrypt = des_decrypt_wrapper;
 142
 143         ctx->blocksize = DES_BLOCK_SIZE;
 144         break;
 145
 146     case QCRYPTO_CIPHER_ALG_AES_128:
 147     case QCRYPTO_CIPHER_ALG_AES_192:
 148     case QCRYPTO_CIPHER_ALG_AES_256:
 149         ctx->ctx_encrypt = g_new0(struct aes_ctx, 1);
 150         ctx->ctx_decrypt = g_new0(struct aes_ctx, 1);
 151
 152         aes_set_encrypt_key(ctx->ctx_encrypt, nkey, key);
 153         aes_set_decrypt_key(ctx->ctx_decrypt, nkey, key);
 154
 155         ctx->alg_encrypt = aes_encrypt_wrapper;
 156         ctx->alg_decrypt = aes_decrypt_wrapper;
 157
 158         ctx->blocksize = AES_BLOCK_SIZE;
 159         break;
 160
 161     case QCRYPTO_CIPHER_ALG_CAST5_128:
 162         ctx->ctx_encrypt = g_new0(struct cast128_ctx, 1);
 163         ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
 164
 165         cast5_set_key(ctx->ctx_encrypt, nkey, key);
 166
 167         ctx->alg_encrypt = cast128_encrypt_wrapper;
 168         ctx->alg_decrypt = cast128_decrypt_wrapper;
 169
 170         ctx->blocksize = CAST128_BLOCK_SIZE;
 171         break;
 172     default:
 173         error_setg(errp, "Unsupported cipher algorithm %d", alg);
 174         goto error;
 175     }
 176
 177     ctx->iv = g_new0(uint8_t, ctx->blocksize);
 178     cipher->opaque = ctx;
 179
 180     return cipher;
 181
 182  error:
 183     g_free(cipher);
 184     g_free(ctx);
 185     return NULL;
 186 }
 187
 188
 189 void qcrypto_cipher_free(QCryptoCipher *cipher)
 190 {
 191     QCryptoCipherNettle *ctx;
 192
 193     if (!cipher) {
 194         return;
 195     }
 196
 197     ctx = cipher->opaque;
 198     g_free(ctx->iv);
 199     g_free(ctx->ctx_encrypt);
 200     g_free(ctx->ctx_decrypt);
 201     g_free(ctx);
 202     g_free(cipher);
 203 }
 204
 205
 206 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 207                            const void *in,
 208                            void *out,
 209                            size_t len,
 210                            Error **errp)
 211 {
 212     QCryptoCipherNettle *ctx = cipher->opaque;
 213
 214     if (len % ctx->blocksize) {
 215         error_setg(errp, "Length %zu must be a multiple of block size %zu",
 216                    len, ctx->blocksize);
 217         return -1;
 218     }
 219
 220     switch (cipher->mode) {
 221     case QCRYPTO_CIPHER_MODE_ECB:
 222         ctx->alg_encrypt(ctx->ctx_encrypt, len, out, in);
 223         break;
 224
 225     case QCRYPTO_CIPHER_MODE_CBC:
 226         cbc_encrypt(ctx->ctx_encrypt, ctx->alg_encrypt,
 227                     ctx->blocksize, ctx->iv,
 228                     len, out, in);
 229         break;
 230     default:
 231         error_setg(errp, "Unsupported cipher algorithm %d",
 232                    cipher->alg);
 233         return -1;
 234     }
 235     return 0;
 236 }
 237
 238
 239 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 240                            const void *in,
 241                            void *out,
 242                            size_t len,
 243                            Error **errp)
 244 {
 245     QCryptoCipherNettle *ctx = cipher->opaque;
 246
 247     if (len % ctx->blocksize) {
 248         error_setg(errp, "Length %zu must be a multiple of block size %zu",
 249                    len, ctx->blocksize);
 250         return -1;
 251     }
 252
 253     switch (cipher->mode) {
 254     case QCRYPTO_CIPHER_MODE_ECB:
 255         ctx->alg_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
 256                          len, out, in);
 257         break;
 258
 259     case QCRYPTO_CIPHER_MODE_CBC:
 260         cbc_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
 261                     ctx->alg_decrypt, ctx->blocksize, ctx->iv,
 262                     len, out, in);
 263         break;
 264     default:
 265         error_setg(errp, "Unsupported cipher algorithm %d",
 266                    cipher->alg);
 267         return -1;
 268     }
 269     return 0;
 270 }
 271
 272 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
 273                          const uint8_t *iv, size_t niv,
 274                          Error **errp)
 275 {
 276     QCryptoCipherNettle *ctx = cipher->opaque;
 277     if (niv != ctx->blocksize) {
 278         error_setg(errp, "Expected IV size %zu not %zu",
 279                    ctx->blocksize, niv);
 280         return -1;
 281     }
 282     memcpy(ctx->iv, iv, niv);
 283     return 0;
 284 }