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 <nettle/nettle-types.h>
  22 #include <nettle/aes.h>
  23 #include <nettle/des.h>
  24 #include <nettle/cbc.h>
  25
  26 #if CONFIG_NETTLE_VERSION_MAJOR < 3
  27 typedef nettle_crypt_func nettle_cipher_func;
  28
  29 typedef void *       cipher_ctx_t;
  30 typedef unsigned     cipher_length_t;
  31 #else
  32 typedef const void * cipher_ctx_t;
  33 typedef size_t       cipher_length_t;
  34 #endif
  35
  36 static nettle_cipher_func aes_encrypt_wrapper;
  37 static nettle_cipher_func aes_decrypt_wrapper;
  38 static nettle_cipher_func des_encrypt_wrapper;
  39 static nettle_cipher_func des_decrypt_wrapper;
  40
  41 static void aes_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  42                                 uint8_t *dst, const uint8_t *src)
  43 {
  44     aes_encrypt(ctx, length, dst, src);
  45 }
  46
  47 static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  48                                 uint8_t *dst, const uint8_t *src)
  49 {
  50     aes_decrypt(ctx, length, dst, src);
  51 }
  52
  53 static void des_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  54                                 uint8_t *dst, const uint8_t *src)
  55 {
  56     des_encrypt(ctx, length, dst, src);
  57 }
  58
  59 static void des_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
  60                                 uint8_t *dst, const uint8_t *src)
  61 {
  62     des_decrypt(ctx, length, dst, src);
  63 }
  64
  65 typedef struct QCryptoCipherNettle QCryptoCipherNettle;
  66 struct QCryptoCipherNettle {
  67     void *ctx_encrypt;
  68     void *ctx_decrypt;
  69     nettle_cipher_func *alg_encrypt;
  70     nettle_cipher_func *alg_decrypt;
  71     uint8_t *iv;
  72     size_t blocksize;
  73 };
  74
  75 bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
  76 {
  77     switch (alg) {
  78     case QCRYPTO_CIPHER_ALG_DES_RFB:
  79     case QCRYPTO_CIPHER_ALG_AES_128:
  80     case QCRYPTO_CIPHER_ALG_AES_192:
  81     case QCRYPTO_CIPHER_ALG_AES_256:
  82         return true;
  83     default:
  84         return false;
  85     }
  86 }
  87
  88
  89 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
  90                                   QCryptoCipherMode mode,
  91                                   const uint8_t *key, size_t nkey,
  92                                   Error **errp)
  93 {
  94     QCryptoCipher *cipher;
  95     QCryptoCipherNettle *ctx;
  96     uint8_t *rfbkey;
  97
  98     switch (mode) {
  99     case QCRYPTO_CIPHER_MODE_ECB:
 100     case QCRYPTO_CIPHER_MODE_CBC:
 101         break;
 102     default:
 103         error_setg(errp, "Unsupported cipher mode %d", mode);
 104         return NULL;
 105     }
 106
 107     if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
 108         return NULL;
 109     }
 110
 111     cipher = g_new0(QCryptoCipher, 1);
 112     cipher->alg = alg;
 113     cipher->mode = mode;
 114
 115     ctx = g_new0(QCryptoCipherNettle, 1);
 116
 117     switch (alg) {
 118     case QCRYPTO_CIPHER_ALG_DES_RFB:
 119         ctx->ctx_encrypt = g_new0(struct des_ctx, 1);
 120         ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
 121         rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
 122         des_set_key(ctx->ctx_encrypt, rfbkey);
 123         g_free(rfbkey);
 124
 125         ctx->alg_encrypt = des_encrypt_wrapper;
 126         ctx->alg_decrypt = des_decrypt_wrapper;
 127
 128         ctx->blocksize = DES_BLOCK_SIZE;
 129         break;
 130
 131     case QCRYPTO_CIPHER_ALG_AES_128:
 132     case QCRYPTO_CIPHER_ALG_AES_192:
 133     case QCRYPTO_CIPHER_ALG_AES_256:
 134         ctx->ctx_encrypt = g_new0(struct aes_ctx, 1);
 135         ctx->ctx_decrypt = g_new0(struct aes_ctx, 1);
 136
 137         aes_set_encrypt_key(ctx->ctx_encrypt, nkey, key);
 138         aes_set_decrypt_key(ctx->ctx_decrypt, nkey, key);
 139
 140         ctx->alg_encrypt = aes_encrypt_wrapper;
 141         ctx->alg_decrypt = aes_decrypt_wrapper;
 142
 143         ctx->blocksize = AES_BLOCK_SIZE;
 144         break;
 145     default:
 146         error_setg(errp, "Unsupported cipher algorithm %d", alg);
 147         goto error;
 148     }
 149
 150     ctx->iv = g_new0(uint8_t, ctx->blocksize);
 151     cipher->opaque = ctx;
 152
 153     return cipher;
 154
 155  error:
 156     g_free(cipher);
 157     g_free(ctx);
 158     return NULL;
 159 }
 160
 161
 162 void qcrypto_cipher_free(QCryptoCipher *cipher)
 163 {
 164     QCryptoCipherNettle *ctx;
 165
 166     if (!cipher) {
 167         return;
 168     }
 169
 170     ctx = cipher->opaque;
 171     g_free(ctx->iv);
 172     g_free(ctx->ctx_encrypt);
 173     g_free(ctx->ctx_decrypt);
 174     g_free(ctx);
 175     g_free(cipher);
 176 }
 177
 178
 179 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 180                            const void *in,
 181                            void *out,
 182                            size_t len,
 183                            Error **errp)
 184 {
 185     QCryptoCipherNettle *ctx = cipher->opaque;
 186
 187     if (len % ctx->blocksize) {
 188         error_setg(errp, "Length %zu must be a multiple of block size %zu",
 189                    len, ctx->blocksize);
 190         return -1;
 191     }
 192
 193     switch (cipher->mode) {
 194     case QCRYPTO_CIPHER_MODE_ECB:
 195         ctx->alg_encrypt(ctx->ctx_encrypt, len, out, in);
 196         break;
 197
 198     case QCRYPTO_CIPHER_MODE_CBC:
 199         cbc_encrypt(ctx->ctx_encrypt, ctx->alg_encrypt,
 200                     ctx->blocksize, ctx->iv,
 201                     len, out, in);
 202         break;
 203     default:
 204         error_setg(errp, "Unsupported cipher algorithm %d",
 205                    cipher->alg);
 206         return -1;
 207     }
 208     return 0;
 209 }
 210
 211
 212 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 213                            const void *in,
 214                            void *out,
 215                            size_t len,
 216                            Error **errp)
 217 {
 218     QCryptoCipherNettle *ctx = cipher->opaque;
 219
 220     if (len % ctx->blocksize) {
 221         error_setg(errp, "Length %zu must be a multiple of block size %zu",
 222                    len, ctx->blocksize);
 223         return -1;
 224     }
 225
 226     switch (cipher->mode) {
 227     case QCRYPTO_CIPHER_MODE_ECB:
 228         ctx->alg_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
 229                          len, out, in);
 230         break;
 231
 232     case QCRYPTO_CIPHER_MODE_CBC:
 233         cbc_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
 234                     ctx->alg_decrypt, ctx->blocksize, ctx->iv,
 235                     len, out, in);
 236         break;
 237     default:
 238         error_setg(errp, "Unsupported cipher algorithm %d",
 239                    cipher->alg);
 240         return -1;
 241     }
 242     return 0;
 243 }
 244
 245 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
 246                          const uint8_t *iv, size_t niv,
 247                          Error **errp)
 248 {
 249     QCryptoCipherNettle *ctx = cipher->opaque;
 250     if (niv != ctx->blocksize) {
 251         error_setg(errp, "Expected IV size %zu not %zu",
 252                    ctx->blocksize, niv);
 253         return -1;
 254     }
 255     memcpy(ctx->iv, iv, niv);
 256     return 0;
 257 }