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_CAST5_128] = 16, 32 [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16, 33 [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24, 34 [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32, 35 [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16, 36 [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24, 37 [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32, 38 }; 39 40 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = { 41 [QCRYPTO_CIPHER_ALG_AES_128] = 16, 42 [QCRYPTO_CIPHER_ALG_AES_192] = 16, 43 [QCRYPTO_CIPHER_ALG_AES_256] = 16, 44 [QCRYPTO_CIPHER_ALG_DES_RFB] = 8, 45 [QCRYPTO_CIPHER_ALG_CAST5_128] = 8, 46 [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16, 47 [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16, 48 [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16, 49 [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16, 50 [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16, 51 [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16, 52 }; 53 54 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = { 55 [QCRYPTO_CIPHER_MODE_ECB] = false, 56 [QCRYPTO_CIPHER_MODE_CBC] = true, 57 [QCRYPTO_CIPHER_MODE_XTS] = true, 58 }; 59 60 61 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg) 62 { 63 if (alg >= G_N_ELEMENTS(alg_key_len)) { 64 return 0; 65 } 66 return alg_block_len[alg]; 67 } 68 69 70 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg) 71 { 72 if (alg >= G_N_ELEMENTS(alg_key_len)) { 73 return 0; 74 } 75 return alg_key_len[alg]; 76 } 77 78 79 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg, 80 QCryptoCipherMode mode) 81 { 82 if (alg >= G_N_ELEMENTS(alg_block_len)) { 83 return 0; 84 } 85 if (mode >= G_N_ELEMENTS(mode_need_iv)) { 86 return 0; 87 } 88 89 if (mode_need_iv[mode]) { 90 return alg_block_len[alg]; 91 } 92 return 0; 93 } 94 95 96 static bool 97 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg, 98 QCryptoCipherMode mode, 99 size_t nkey, 100 Error **errp) 101 { 102 if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) { 103 error_setg(errp, "Cipher algorithm %d out of range", 104 alg); 105 return false; 106 } 107 108 if (mode == QCRYPTO_CIPHER_MODE_XTS) { 109 if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) { 110 error_setg(errp, "XTS mode not compatible with DES-RFB"); 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