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 [QCRYPTO_CIPHER_MODE_CTR] = true, 59 }; 60 61 62 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg) 63 { 64 if (alg >= G_N_ELEMENTS(alg_key_len)) { 65 return 0; 66 } 67 return alg_block_len[alg]; 68 } 69 70 71 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg) 72 { 73 if (alg >= G_N_ELEMENTS(alg_key_len)) { 74 return 0; 75 } 76 return alg_key_len[alg]; 77 } 78 79 80 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg, 81 QCryptoCipherMode mode) 82 { 83 if (alg >= G_N_ELEMENTS(alg_block_len)) { 84 return 0; 85 } 86 if (mode >= G_N_ELEMENTS(mode_need_iv)) { 87 return 0; 88 } 89 90 if (mode_need_iv[mode]) { 91 return alg_block_len[alg]; 92 } 93 return 0; 94 } 95 96 97 static bool 98 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg, 99 QCryptoCipherMode mode, 100 size_t nkey, 101 Error **errp) 102 { 103 if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) { 104 error_setg(errp, "Cipher algorithm %d out of range", 105 alg); 106 return false; 107 } 108 109 if (mode == QCRYPTO_CIPHER_MODE_XTS) { 110 if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) { 111 error_setg(errp, "XTS mode not compatible with DES-RFB"); 112 return false; 113 } 114 if (nkey % 2) { 115 error_setg(errp, "XTS cipher key length should be a multiple of 2"); 116 return false; 117 } 118 119 if (alg_key_len[alg] != (nkey / 2)) { 120 error_setg(errp, "Cipher key length %zu should be %zu", 121 nkey, alg_key_len[alg] * 2); 122 return false; 123 } 124 } else { 125 if (alg_key_len[alg] != nkey) { 126 error_setg(errp, "Cipher key length %zu should be %zu", 127 nkey, alg_key_len[alg]); 128 return false; 129 } 130 } 131 return true; 132 } 133 134 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE) 135 static uint8_t * 136 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key, 137 size_t nkey) 138 { 139 uint8_t *ret = g_new0(uint8_t, nkey); 140 size_t i; 141 for (i = 0; i < nkey; i++) { 142 uint8_t r = key[i]; 143 r = (r & 0xf0) >> 4 | (r & 0x0f) << 4; 144 r = (r & 0xcc) >> 2 | (r & 0x33) << 2; 145 r = (r & 0xaa) >> 1 | (r & 0x55) << 1; 146 ret[i] = r; 147 } 148 return ret; 149 } 150 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */ 151 152 #ifdef CONFIG_GCRYPT 153 #include "crypto/cipher-gcrypt.c" 154 #elif defined CONFIG_NETTLE 155 #include "crypto/cipher-nettle.c" 156 #else 157 #include "crypto/cipher-builtin.c" 158 #endif 159