1/* 2 * QEMU Crypto cipher built-in 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 2.1 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 "crypto/aes.h" 22 23typedef struct QCryptoCipherBuiltinAESContext QCryptoCipherBuiltinAESContext; 24struct QCryptoCipherBuiltinAESContext { 25 AES_KEY enc; 26 AES_KEY dec; 27}; 28 29typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES; 30struct QCryptoCipherBuiltinAES { 31 QCryptoCipher base; 32 QCryptoCipherBuiltinAESContext key; 33 uint8_t iv[AES_BLOCK_SIZE]; 34}; 35 36 37static inline bool qcrypto_length_check(size_t len, size_t blocksize, 38 Error **errp) 39{ 40 if (unlikely(len & (blocksize - 1))) { 41 error_setg(errp, "Length %zu must be a multiple of block size %zu", 42 len, blocksize); 43 return false; 44 } 45 return true; 46} 47 48static void qcrypto_cipher_ctx_free(QCryptoCipher *cipher) 49{ 50 g_free(cipher); 51} 52 53static int qcrypto_cipher_no_setiv(QCryptoCipher *cipher, 54 const uint8_t *iv, size_t niv, 55 Error **errp) 56{ 57 error_setg(errp, "Setting IV is not supported"); 58 return -1; 59} 60 61static void do_aes_encrypt_ecb(const void *vctx, 62 size_t len, 63 uint8_t *out, 64 const uint8_t *in) 65{ 66 const QCryptoCipherBuiltinAESContext *ctx = vctx; 67 68 /* We have already verified that len % AES_BLOCK_SIZE == 0. */ 69 while (len) { 70 AES_encrypt(in, out, &ctx->enc); 71 in += AES_BLOCK_SIZE; 72 out += AES_BLOCK_SIZE; 73 len -= AES_BLOCK_SIZE; 74 } 75} 76 77static void do_aes_decrypt_ecb(const void *vctx, 78 size_t len, 79 uint8_t *out, 80 const uint8_t *in) 81{ 82 const QCryptoCipherBuiltinAESContext *ctx = vctx; 83 84 /* We have already verified that len % AES_BLOCK_SIZE == 0. */ 85 while (len) { 86 AES_decrypt(in, out, &ctx->dec); 87 in += AES_BLOCK_SIZE; 88 out += AES_BLOCK_SIZE; 89 len -= AES_BLOCK_SIZE; 90 } 91} 92 93static void do_aes_encrypt_cbc(const AES_KEY *key, 94 size_t len, 95 uint8_t *out, 96 const uint8_t *in, 97 uint8_t *ivec) 98{ 99 uint8_t tmp[AES_BLOCK_SIZE]; 100 size_t n; 101 102 /* We have already verified that len % AES_BLOCK_SIZE == 0. */ 103 while (len) { 104 for (n = 0; n < AES_BLOCK_SIZE; ++n) { 105 tmp[n] = in[n] ^ ivec[n]; 106 } 107 AES_encrypt(tmp, out, key); 108 memcpy(ivec, out, AES_BLOCK_SIZE); 109 len -= AES_BLOCK_SIZE; 110 in += AES_BLOCK_SIZE; 111 out += AES_BLOCK_SIZE; 112 } 113} 114 115static void do_aes_decrypt_cbc(const AES_KEY *key, 116 size_t len, 117 uint8_t *out, 118 const uint8_t *in, 119 uint8_t *ivec) 120{ 121 uint8_t tmp[AES_BLOCK_SIZE]; 122 size_t n; 123 124 /* We have already verified that len % AES_BLOCK_SIZE == 0. */ 125 while (len) { 126 memcpy(tmp, in, AES_BLOCK_SIZE); 127 AES_decrypt(in, out, key); 128 for (n = 0; n < AES_BLOCK_SIZE; ++n) { 129 out[n] ^= ivec[n]; 130 } 131 memcpy(ivec, tmp, AES_BLOCK_SIZE); 132 len -= AES_BLOCK_SIZE; 133 in += AES_BLOCK_SIZE; 134 out += AES_BLOCK_SIZE; 135 } 136} 137 138static int qcrypto_cipher_aes_encrypt_ecb(QCryptoCipher *cipher, 139 const void *in, void *out, 140 size_t len, Error **errp) 141{ 142 QCryptoCipherBuiltinAES *ctx 143 = container_of(cipher, QCryptoCipherBuiltinAES, base); 144 145 if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) { 146 return -1; 147 } 148 do_aes_encrypt_ecb(&ctx->key, len, out, in); 149 return 0; 150} 151 152static int qcrypto_cipher_aes_decrypt_ecb(QCryptoCipher *cipher, 153 const void *in, void *out, 154 size_t len, Error **errp) 155{ 156 QCryptoCipherBuiltinAES *ctx 157 = container_of(cipher, QCryptoCipherBuiltinAES, base); 158 159 if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) { 160 return -1; 161 } 162 do_aes_decrypt_ecb(&ctx->key, len, out, in); 163 return 0; 164} 165 166static int qcrypto_cipher_aes_encrypt_cbc(QCryptoCipher *cipher, 167 const void *in, void *out, 168 size_t len, Error **errp) 169{ 170 QCryptoCipherBuiltinAES *ctx 171 = container_of(cipher, QCryptoCipherBuiltinAES, base); 172 173 if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) { 174 return -1; 175 } 176 do_aes_encrypt_cbc(&ctx->key.enc, len, out, in, ctx->iv); 177 return 0; 178} 179 180static int qcrypto_cipher_aes_decrypt_cbc(QCryptoCipher *cipher, 181 const void *in, void *out, 182 size_t len, Error **errp) 183{ 184 QCryptoCipherBuiltinAES *ctx 185 = container_of(cipher, QCryptoCipherBuiltinAES, base); 186 187 if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) { 188 return -1; 189 } 190 do_aes_decrypt_cbc(&ctx->key.dec, len, out, in, ctx->iv); 191 return 0; 192} 193 194static int qcrypto_cipher_aes_setiv(QCryptoCipher *cipher, const uint8_t *iv, 195 size_t niv, Error **errp) 196{ 197 QCryptoCipherBuiltinAES *ctx 198 = container_of(cipher, QCryptoCipherBuiltinAES, base); 199 200 if (niv != AES_BLOCK_SIZE) { 201 error_setg(errp, "IV must be %d bytes not %zu", 202 AES_BLOCK_SIZE, niv); 203 return -1; 204 } 205 206 memcpy(ctx->iv, iv, AES_BLOCK_SIZE); 207 return 0; 208} 209 210static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_ecb = { 211 .cipher_encrypt = qcrypto_cipher_aes_encrypt_ecb, 212 .cipher_decrypt = qcrypto_cipher_aes_decrypt_ecb, 213 .cipher_setiv = qcrypto_cipher_no_setiv, 214 .cipher_free = qcrypto_cipher_ctx_free, 215}; 216 217static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_cbc = { 218 .cipher_encrypt = qcrypto_cipher_aes_encrypt_cbc, 219 .cipher_decrypt = qcrypto_cipher_aes_decrypt_cbc, 220 .cipher_setiv = qcrypto_cipher_aes_setiv, 221 .cipher_free = qcrypto_cipher_ctx_free, 222}; 223 224bool qcrypto_cipher_supports(QCryptoCipherAlgo alg, 225 QCryptoCipherMode mode) 226{ 227 switch (alg) { 228 case QCRYPTO_CIPHER_ALGO_AES_128: 229 case QCRYPTO_CIPHER_ALGO_AES_192: 230 case QCRYPTO_CIPHER_ALGO_AES_256: 231 switch (mode) { 232 case QCRYPTO_CIPHER_MODE_ECB: 233 case QCRYPTO_CIPHER_MODE_CBC: 234 return true; 235 default: 236 return false; 237 } 238 break; 239 default: 240 return false; 241 } 242} 243 244static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgo alg, 245 QCryptoCipherMode mode, 246 const uint8_t *key, 247 size_t nkey, 248 Error **errp) 249{ 250 if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) { 251 return NULL; 252 } 253 254 switch (alg) { 255 case QCRYPTO_CIPHER_ALGO_AES_128: 256 case QCRYPTO_CIPHER_ALGO_AES_192: 257 case QCRYPTO_CIPHER_ALGO_AES_256: 258 { 259 QCryptoCipherBuiltinAES *ctx; 260 const QCryptoCipherDriver *drv; 261 262 switch (mode) { 263 case QCRYPTO_CIPHER_MODE_ECB: 264 drv = &qcrypto_cipher_aes_driver_ecb; 265 break; 266 case QCRYPTO_CIPHER_MODE_CBC: 267 drv = &qcrypto_cipher_aes_driver_cbc; 268 break; 269 default: 270 goto bad_mode; 271 } 272 273 ctx = g_new0(QCryptoCipherBuiltinAES, 1); 274 ctx->base.driver = drv; 275 276 if (AES_set_encrypt_key(key, nkey * 8, &ctx->key.enc)) { 277 error_setg(errp, "Failed to set encryption key"); 278 goto error; 279 } 280 if (AES_set_decrypt_key(key, nkey * 8, &ctx->key.dec)) { 281 error_setg(errp, "Failed to set decryption key"); 282 goto error; 283 } 284 285 return &ctx->base; 286 287 error: 288 g_free(ctx); 289 return NULL; 290 } 291 292 default: 293 error_setg(errp, 294 "Unsupported cipher algorithm %s", 295 QCryptoCipherAlgo_str(alg)); 296 return NULL; 297 } 298 299 bad_mode: 300 error_setg(errp, "Unsupported cipher mode %s", 301 QCryptoCipherMode_str(mode)); 302 return NULL; 303} 304