| 1 | /* |
| 2 | * QEMU Crypto block device encryption |
| 3 | * |
| 4 | * Copyright (c) 2015-2016 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 | #ifndef QCRYPTO_BLOCK_H |
| 22 | #define QCRYPTO_BLOCK_H |
| 23 | |
| 24 | #include "crypto/cipher.h" |
| 25 | #include "crypto/ivgen.h" |
| 26 | |
| 27 | typedef struct QCryptoBlock QCryptoBlock; |
| 28 | |
| 29 | /* See also QCryptoBlockFormat, QCryptoBlockCreateOptions |
| 30 | * and QCryptoBlockOpenOptions in qapi/crypto.json */ |
| 31 | |
| 32 | typedef int (*QCryptoBlockReadFunc)(QCryptoBlock *block, |
| 33 | size_t offset, |
| 34 | uint8_t *buf, |
| 35 | size_t buflen, |
| 36 | void *opaque, |
| 37 | Error **errp); |
| 38 | |
| 39 | typedef int (*QCryptoBlockInitFunc)(QCryptoBlock *block, |
| 40 | size_t headerlen, |
| 41 | void *opaque, |
| 42 | Error **errp); |
| 43 | |
| 44 | typedef int (*QCryptoBlockWriteFunc)(QCryptoBlock *block, |
| 45 | size_t offset, |
| 46 | const uint8_t *buf, |
| 47 | size_t buflen, |
| 48 | void *opaque, |
| 49 | Error **errp); |
| 50 | |
| 51 | /** |
| 52 | * qcrypto_block_has_format: |
| 53 | * @format: the encryption format |
| 54 | * @buf: the data from head of the volume |
| 55 | * @len: the length of @buf in bytes |
| 56 | * |
| 57 | * Given @len bytes of data from the head of a storage volume |
| 58 | * in @buf, probe to determine if the volume has the encryption |
| 59 | * format specified in @format. |
| 60 | * |
| 61 | * Returns: true if the data in @buf matches @format |
| 62 | */ |
| 63 | bool qcrypto_block_has_format(QCryptoBlockFormat format, |
| 64 | const uint8_t *buf, |
| 65 | size_t buflen); |
| 66 | |
| 67 | typedef enum { |
| 68 | QCRYPTO_BLOCK_OPEN_NO_IO = (1 << 0), |
| 69 | QCRYPTO_BLOCK_OPEN_DETACHED = (1 << 1), |
| 70 | } QCryptoBlockOpenFlags; |
| 71 | |
| 72 | /** |
| 73 | * qcrypto_block_open: |
| 74 | * @options: the encryption options |
| 75 | * @optprefix: name prefix for options |
| 76 | * @readfunc: callback for reading data from the volume |
| 77 | * @opaque: data to pass to @readfunc |
| 78 | * @flags: bitmask of QCryptoBlockOpenFlags values |
| 79 | * @errp: pointer to a NULL-initialized error object |
| 80 | * |
| 81 | * Create a new block encryption object for an existing |
| 82 | * storage volume encrypted with format identified by |
| 83 | * the parameters in @options. |
| 84 | * |
| 85 | * This will use @readfunc to initialize the encryption |
| 86 | * context based on the volume header(s), extracting the |
| 87 | * master key(s) as required. |
| 88 | * |
| 89 | * If @flags contains QCRYPTO_BLOCK_OPEN_NO_IO then |
| 90 | * the open process will be optimized to skip any parts |
| 91 | * that are only required to perform I/O. In particular |
| 92 | * this would usually avoid the need to decrypt any |
| 93 | * master keys. The only thing that can be done with |
| 94 | * the resulting QCryptoBlock object would be to query |
| 95 | * metadata such as the payload offset. There will be |
| 96 | * no cipher or ivgen objects available. |
| 97 | * |
| 98 | * If @flags contains QCRYPTO_BLOCK_OPEN_DETACHED then |
| 99 | * the open process will be optimized to skip the LUKS |
| 100 | * payload overlap check. |
| 101 | * |
| 102 | * If any part of initializing the encryption context |
| 103 | * fails an error will be returned. This could be due |
| 104 | * to the volume being in the wrong format, a cipher |
| 105 | * or IV generator algorithm that is not supported, |
| 106 | * or incorrect passphrases. |
| 107 | * |
| 108 | * Returns: a block encryption format, or NULL on error |
| 109 | */ |
| 110 | QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options, |
| 111 | const char *optprefix, |
| 112 | QCryptoBlockReadFunc readfunc, |
| 113 | void *opaque, |
| 114 | unsigned int flags, |
| 115 | Error **errp); |
| 116 | |
| 117 | typedef enum { |
| 118 | QCRYPTO_BLOCK_CREATE_DETACHED = (1 << 0), |
| 119 | } QCryptoBlockCreateFlags; |
| 120 | |
| 121 | /** |
| 122 | * qcrypto_block_create: |
| 123 | * @options: the encryption options |
| 124 | * @optprefix: name prefix for options |
| 125 | * @initfunc: callback for initializing volume header |
| 126 | * @writefunc: callback for writing data to the volume header |
| 127 | * @opaque: data to pass to @initfunc and @writefunc |
| 128 | * @flags: bitmask of QCryptoBlockCreateFlags values |
| 129 | * @errp: pointer to a NULL-initialized error object |
| 130 | * |
| 131 | * Create a new block encryption object for initializing |
| 132 | * a storage volume to be encrypted with format identified |
| 133 | * by the parameters in @options. |
| 134 | * |
| 135 | * This method will allocate space for a new volume header |
| 136 | * using @initfunc and then write header data using @writefunc, |
| 137 | * generating new master keys, etc as required. Any existing |
| 138 | * data present on the volume will be irrevocably destroyed. |
| 139 | * |
| 140 | * If @flags contains QCRYPTO_BLOCK_CREATE_DETACHED then |
| 141 | * the open process will set the payload_offset_sector to 0 |
| 142 | * to specify the starting point for the read/write of a |
| 143 | * detached LUKS header image. |
| 144 | * |
| 145 | * If any part of initializing the encryption context |
| 146 | * fails an error will be returned. This could be due |
| 147 | * to the volume being in the wrong format, a cipher |
| 148 | * or IV generator algorithm that is not supported, |
| 149 | * or incorrect passphrases. |
| 150 | * |
| 151 | * Returns: a block encryption format, or NULL on error |
| 152 | */ |
| 153 | QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options, |
| 154 | const char *optprefix, |
| 155 | QCryptoBlockInitFunc initfunc, |
| 156 | QCryptoBlockWriteFunc writefunc, |
| 157 | void *opaque, |
| 158 | unsigned int flags, |
| 159 | Error **errp); |
| 160 | |
| 161 | /** |
| 162 | * qcrypto_block_amend_options: |
| 163 | * @block: the block encryption object |
| 164 | * |
| 165 | * @readfunc: callback for reading data from the volume header |
| 166 | * @writefunc: callback for writing data to the volume header |
| 167 | * @opaque: data to pass to @readfunc and @writefunc |
| 168 | * @options: the new/amended encryption options |
| 169 | * @force: hint for the driver to allow unsafe operation |
| 170 | * @errp: error pointer |
| 171 | * |
| 172 | * Changes the crypto options of the encryption format |
| 173 | * |
| 174 | */ |
| 175 | int qcrypto_block_amend_options(QCryptoBlock *block, |
| 176 | QCryptoBlockReadFunc readfunc, |
| 177 | QCryptoBlockWriteFunc writefunc, |
| 178 | void *opaque, |
| 179 | QCryptoBlockAmendOptions *options, |
| 180 | bool force, |
| 181 | Error **errp); |
| 182 | |
| 183 | |
| 184 | /** |
| 185 | * qcrypto_block_calculate_payload_offset: |
| 186 | * @create_opts: the encryption options |
| 187 | * @optprefix: name prefix for options |
| 188 | * @len: output for number of header bytes before payload |
| 189 | * @errp: pointer to a NULL-initialized error object |
| 190 | * |
| 191 | * Calculate the number of header bytes before the payload in an encrypted |
| 192 | * storage volume. The header is an area before the payload that is reserved |
| 193 | * for encryption metadata. |
| 194 | * |
| 195 | * Returns: true on success, false on error |
| 196 | */ |
| 197 | bool |
| 198 | qcrypto_block_calculate_payload_offset(QCryptoBlockCreateOptions *create_opts, |
| 199 | const char *optprefix, |
| 200 | size_t *len, |
| 201 | Error **errp); |
| 202 | |
| 203 | |
| 204 | /** |
| 205 | * qcrypto_block_get_info: |
| 206 | * @block: the block encryption object |
| 207 | * @errp: pointer to a NULL-initialized error object |
| 208 | * |
| 209 | * Get information about the configuration options for the |
| 210 | * block encryption object. This includes details such as |
| 211 | * the cipher algorithms, modes, and initialization vector |
| 212 | * generators. |
| 213 | * |
| 214 | * Returns: a block encryption info object, or NULL on error |
| 215 | */ |
| 216 | QCryptoBlockInfo *qcrypto_block_get_info(QCryptoBlock *block, |
| 217 | Error **errp); |
| 218 | |
| 219 | /** |
| 220 | * @qcrypto_block_decrypt: |
| 221 | * @block: the block encryption object |
| 222 | * @offset: the position at which @iov was read |
| 223 | * @buf: the buffer to decrypt |
| 224 | * @len: the length of @buf in bytes |
| 225 | * @errp: pointer to a NULL-initialized error object |
| 226 | * |
| 227 | * Decrypt @len bytes of cipher text in @buf, writing |
| 228 | * plain text back into @buf. @len and @offset must be |
| 229 | * a multiple of the encryption format sector size. |
| 230 | * |
| 231 | * Returns 0 on success, -1 on failure |
| 232 | */ |
| 233 | int qcrypto_block_decrypt(QCryptoBlock *block, |
| 234 | uint64_t offset, |
| 235 | uint8_t *buf, |
| 236 | size_t len, |
| 237 | Error **errp); |
| 238 | |
| 239 | /** |
| 240 | * @qcrypto_block_encrypt: |
| 241 | * @block: the block encryption object |
| 242 | * @offset: the position at which @iov will be written |
| 243 | * @buf: the buffer to decrypt |
| 244 | * @len: the length of @buf in bytes |
| 245 | * @errp: pointer to a NULL-initialized error object |
| 246 | * |
| 247 | * Encrypt @len bytes of plain text in @buf, writing |
| 248 | * cipher text back into @buf. @len and @offset must be |
| 249 | * a multiple of the encryption format sector size. |
| 250 | * |
| 251 | * Returns 0 on success, -1 on failure |
| 252 | */ |
| 253 | int qcrypto_block_encrypt(QCryptoBlock *block, |
| 254 | uint64_t offset, |
| 255 | uint8_t *buf, |
| 256 | size_t len, |
| 257 | Error **errp); |
| 258 | |
| 259 | /** |
| 260 | * qcrypto_block_get_cipher: |
| 261 | * @block: the block encryption object |
| 262 | * |
| 263 | * Get the cipher to use for payload encryption |
| 264 | * |
| 265 | * Returns: the cipher object |
| 266 | */ |
| 267 | QCryptoCipher *qcrypto_block_get_cipher(QCryptoBlock *block); |
| 268 | |
| 269 | /** |
| 270 | * qcrypto_block_get_ivgen: |
| 271 | * @block: the block encryption object |
| 272 | * |
| 273 | * Get the initialization vector generator to use for |
| 274 | * payload encryption |
| 275 | * |
| 276 | * Returns: the IV generator object |
| 277 | */ |
| 278 | QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block); |
| 279 | |
| 280 | |
| 281 | /** |
| 282 | * qcrypto_block_get_kdf_hash: |
| 283 | * @block: the block encryption object |
| 284 | * |
| 285 | * Get the hash algorithm used with the key derivation |
| 286 | * function |
| 287 | * |
| 288 | * Returns: the hash algorithm |
| 289 | */ |
| 290 | QCryptoHashAlgo qcrypto_block_get_kdf_hash(QCryptoBlock *block); |
| 291 | |
| 292 | /** |
| 293 | * qcrypto_block_get_payload_offset: |
| 294 | * @block: the block encryption object |
| 295 | * |
| 296 | * Get the offset to the payload indicated by the |
| 297 | * encryption header, in bytes. |
| 298 | * |
| 299 | * Returns: the payload offset in bytes |
| 300 | */ |
| 301 | uint64_t qcrypto_block_get_payload_offset(QCryptoBlock *block); |
| 302 | |
| 303 | /** |
| 304 | * qcrypto_block_get_sector_size: |
| 305 | * @block: the block encryption object |
| 306 | * |
| 307 | * Get the size of sectors used for payload encryption. A new |
| 308 | * IV is used at the start of each sector. The encryption |
| 309 | * sector size is not required to match the sector size of the |
| 310 | * underlying storage. For example LUKS will always use a 512 |
| 311 | * byte sector size, even if the volume is on a disk with 4k |
| 312 | * sectors. |
| 313 | * |
| 314 | * Returns: the sector in bytes |
| 315 | */ |
| 316 | uint64_t qcrypto_block_get_sector_size(QCryptoBlock *block); |
| 317 | |
| 318 | /** |
| 319 | * qcrypto_block_free: |
| 320 | * @block: the block encryption object |
| 321 | * |
| 322 | * Release all resources associated with the encryption |
| 323 | * object |
| 324 | */ |
| 325 | void qcrypto_block_free(QCryptoBlock *block); |
| 326 | |
| 327 | G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoBlock, qcrypto_block_free) |
| 328 | |
| 329 | #endif /* QCRYPTO_BLOCK_H */ |