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 #ifndef QCRYPTO_CIPHER_H__ 22 #define QCRYPTO_CIPHER_H__ 23 24 #include "qemu-common.h" 25 26 typedef struct QCryptoCipher QCryptoCipher; 27 28 /* See also "QCryptoCipherAlgorithm" and "QCryptoCipherMode" 29 * enums defined in qapi/crypto.json */ 30 31 /** 32 * QCryptoCipher: 33 * 34 * The QCryptoCipher object provides a way to perform encryption 35 * and decryption of data, with a standard API, regardless of the 36 * algorithm used. It further isolates the calling code from the 37 * details of the specific underlying implementation, whether 38 * built-in, libgcrypt or nettle. 39 * 40 * Each QCryptoCipher object is capable of performing both 41 * encryption and decryption, and can operate in a number 42 * or modes including ECB, CBC. 43 * 44 * <example> 45 * <title>Encrypting data with AES-128 in CBC mode</title> 46 * <programlisting> 47 * QCryptoCipher *cipher; 48 * uint8_t key = ....; 49 * size_t keylen = 16; 50 * uint8_t iv = ....; 51 * 52 * if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 53 * error_report(errp, "Feature <blah> requires AES cipher support"); 54 * return -1; 55 * } 56 * 57 * cipher = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_128, 58 * QCRYPTO_CIPHER_MODE_CBC, 59 * key, keylen, 60 * errp); 61 * if (!cipher) { 62 * return -1; 63 * } 64 * 65 * if (qcrypto_cipher_set_iv(cipher, iv, keylen, errp) < 0) { 66 * return -1; 67 * } 68 * 69 * if (qcrypto_cipher_encrypt(cipher, rawdata, encdata, datalen, errp) < 0) { 70 * return -1; 71 * } 72 * 73 * qcrypto_cipher_free(cipher); 74 * </programlisting> 75 * </example> 76 * 77 */ 78 79 struct QCryptoCipher { 80 QCryptoCipherAlgorithm alg; 81 QCryptoCipherMode mode; 82 void *opaque; 83 }; 84 85 /** 86 * qcrypto_cipher_supports: 87 * @alg: the cipher algorithm 88 * 89 * Determine if @alg cipher algorithm is supported by the 90 * current configured build 91 * 92 * Returns: true if the algorithm is supported, false otherwise 93 */ 94 bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg); 95 96 /** 97 * qcrypto_cipher_get_block_len: 98 * @alg: the cipher algorithm 99 * 100 * Get the required data block size in bytes. When 101 * encrypting data, it must be a multiple of the 102 * block size. 103 * 104 * Returns: the block size in bytes 105 */ 106 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg); 107 108 109 /** 110 * qcrypto_cipher_get_key_len: 111 * @alg: the cipher algorithm 112 * 113 * Get the required key size in bytes. 114 * 115 * Returns: the key size in bytes 116 */ 117 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg); 118 119 120 /** 121 * qcrypto_cipher_get_iv_len: 122 * @alg: the cipher algorithm 123 * @mode: the cipher mode 124 * 125 * Get the required initialization vector size 126 * in bytes, if one is required. 127 * 128 * Returns: the IV size in bytes, or 0 if no IV is permitted 129 */ 130 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg, 131 QCryptoCipherMode mode); 132 133 134 /** 135 * qcrypto_cipher_new: 136 * @alg: the cipher algorithm 137 * @mode: the cipher usage mode 138 * @key: the private key bytes 139 * @nkey: the length of @key 140 * @errp: pointer to a NULL-initialized error object 141 * 142 * Creates a new cipher object for encrypting/decrypting 143 * data with the algorithm @alg in the usage mode @mode. 144 * 145 * The @key parameter provides the bytes representing 146 * the encryption/decryption key to use. The @nkey parameter 147 * specifies the length of @key in bytes. Each algorithm has 148 * one or more valid key lengths, and it is an error to provide 149 * a key of the incorrect length. 150 * 151 * The returned cipher object must be released with 152 * qcrypto_cipher_free() when no longer required 153 * 154 * Returns: a new cipher object, or NULL on error 155 */ 156 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg, 157 QCryptoCipherMode mode, 158 const uint8_t *key, size_t nkey, 159 Error **errp); 160 161 /** 162 * qcrypto_cipher_free: 163 * @cipher: the cipher object 164 * 165 * Release the memory associated with @cipher that 166 * was previously allocated by qcrypto_cipher_new() 167 */ 168 void qcrypto_cipher_free(QCryptoCipher *cipher); 169 170 /** 171 * qcrypto_cipher_encrypt: 172 * @cipher: the cipher object 173 * @in: buffer holding the plain text input data 174 * @out: buffer to fill with the cipher text output data 175 * @len: the length of @in and @out buffers 176 * @errp: pointer to a NULL-initialized error object 177 * 178 * Encrypts the plain text stored in @in, filling 179 * @out with the resulting ciphered text. Both the 180 * @in and @out buffers must have the same size, 181 * given by @len. 182 * 183 * Returns: 0 on success, or -1 on error 184 */ 185 int qcrypto_cipher_encrypt(QCryptoCipher *cipher, 186 const void *in, 187 void *out, 188 size_t len, 189 Error **errp); 190 191 192 /** 193 * qcrypto_cipher_decrypt: 194 * @cipher: the cipher object 195 * @in: buffer holding the cipher text input data 196 * @out: buffer to fill with the plain text output data 197 * @len: the length of @in and @out buffers 198 * @errp: pointer to a NULL-initialized error object 199 * 200 * Decrypts the cipher text stored in @in, filling 201 * @out with the resulting plain text. Both the 202 * @in and @out buffers must have the same size, 203 * given by @len. 204 * 205 * Returns: 0 on success, or -1 on error 206 */ 207 int qcrypto_cipher_decrypt(QCryptoCipher *cipher, 208 const void *in, 209 void *out, 210 size_t len, 211 Error **errp); 212 213 /** 214 * qcrypto_cipher_setiv: 215 * @cipher: the cipher object 216 * @iv: the initialization vector bytes 217 * @niv: the length of @iv 218 * @errpr: pointer to a NULL-initialized error object 219 * 220 * If the @cipher object is setup to use a mode that requires 221 * initialization vectors, this sets the initialization vector 222 * bytes. The @iv data should have the same length as the 223 * cipher key used when originally constructing the cipher 224 * object. It is an error to set an initialization vector 225 * if the cipher mode does not require one. 226 * 227 * Returns: 0 on success, -1 on error 228 */ 229 int qcrypto_cipher_setiv(QCryptoCipher *cipher, 230 const uint8_t *iv, size_t niv, 231 Error **errp); 232 233 #endif /* QCRYPTO_CIPHER_H__ */ 234