1 /* 2 * QEMU Crypto cipher 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 "qapi/error.h" 23 #include "crypto/cipher.h" 24 25 26 static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = { 27 [QCRYPTO_CIPHER_ALG_AES_128] = 16, 28 [QCRYPTO_CIPHER_ALG_AES_192] = 24, 29 [QCRYPTO_CIPHER_ALG_AES_256] = 32, 30 [QCRYPTO_CIPHER_ALG_DES_RFB] = 8, 31 [QCRYPTO_CIPHER_ALG_3DES] = 24, 32 [QCRYPTO_CIPHER_ALG_CAST5_128] = 16, 33 [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16, 34 [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24, 35 [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32, 36 [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16, 37 [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24, 38 [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32, 39 }; 40 41 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = { 42 [QCRYPTO_CIPHER_ALG_AES_128] = 16, 43 [QCRYPTO_CIPHER_ALG_AES_192] = 16, 44 [QCRYPTO_CIPHER_ALG_AES_256] = 16, 45 [QCRYPTO_CIPHER_ALG_DES_RFB] = 8, 46 [QCRYPTO_CIPHER_ALG_3DES] = 8, 47 [QCRYPTO_CIPHER_ALG_CAST5_128] = 8, 48 [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16, 49 [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16, 50 [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16, 51 [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16, 52 [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16, 53 [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16, 54 }; 55 56 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = { 57 [QCRYPTO_CIPHER_MODE_ECB] = false, 58 [QCRYPTO_CIPHER_MODE_CBC] = true, 59 [QCRYPTO_CIPHER_MODE_XTS] = true, 60 [QCRYPTO_CIPHER_MODE_CTR] = true, 61 }; 62 63 64 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg) 65 { 66 assert(alg < G_N_ELEMENTS(alg_key_len)); 67 return alg_block_len[alg]; 68 } 69 70 71 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg) 72 { 73 assert(alg < G_N_ELEMENTS(alg_key_len)); 74 return alg_key_len[alg]; 75 } 76 77 78 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg, 79 QCryptoCipherMode mode) 80 { 81 if (alg >= G_N_ELEMENTS(alg_block_len)) { 82 return 0; 83 } 84 if (mode >= G_N_ELEMENTS(mode_need_iv)) { 85 return 0; 86 } 87 88 if (mode_need_iv[mode]) { 89 return alg_block_len[alg]; 90 } 91 return 0; 92 } 93 94 95 static bool 96 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg, 97 QCryptoCipherMode mode, 98 size_t nkey, 99 Error **errp) 100 { 101 if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) { 102 error_setg(errp, "Cipher algorithm %d out of range", 103 alg); 104 return false; 105 } 106 107 if (mode == QCRYPTO_CIPHER_MODE_XTS) { 108 if (alg == QCRYPTO_CIPHER_ALG_DES_RFB 109 || alg == QCRYPTO_CIPHER_ALG_3DES) { 110 error_setg(errp, "XTS mode not compatible with DES-RFB/3DES"); 111 return false; 112 } 113 if (nkey % 2) { 114 error_setg(errp, "XTS cipher key length should be a multiple of 2"); 115 return false; 116 } 117 118 if (alg_key_len[alg] != (nkey / 2)) { 119 error_setg(errp, "Cipher key length %zu should be %zu", 120 nkey, alg_key_len[alg] * 2); 121 return false; 122 } 123 } else { 124 if (alg_key_len[alg] != nkey) { 125 error_setg(errp, "Cipher key length %zu should be %zu", 126 nkey, alg_key_len[alg]); 127 return false; 128 } 129 } 130 return true; 131 } 132 133 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE) 134 static uint8_t * 135 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key, 136 size_t nkey) 137 { 138 uint8_t *ret = g_new0(uint8_t, nkey); 139 size_t i; 140 for (i = 0; i < nkey; i++) { 141 uint8_t r = key[i]; 142 r = (r & 0xf0) >> 4 | (r & 0x0f) << 4; 143 r = (r & 0xcc) >> 2 | (r & 0x33) << 2; 144 r = (r & 0xaa) >> 1 | (r & 0x55) << 1; 145 ret[i] = r; 146 } 147 return ret; 148 } 149 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */ 150 151 #ifdef CONFIG_GCRYPT 152 #include "crypto/cipher-gcrypt.c" 153 #elif defined CONFIG_NETTLE 154 #include "crypto/cipher-nettle.c" 155 #else 156 #include "crypto/cipher-builtin.c" 157 #endif 158