| 1 | /* |
| 2 | * QEMU crypto TLS session support |
| 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 2.1 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_TLSSESSION_H |
| 22 | #define QCRYPTO_TLSSESSION_H |
| 23 | |
| 24 | #include "crypto/tlscreds.h" |
| 25 | |
| 26 | /** |
| 27 | * QCryptoTLSSession: |
| 28 | * |
| 29 | * The QCryptoTLSSession object encapsulates the |
| 30 | * logic to integrate with a TLS providing library such |
| 31 | * as GNUTLS, to setup and run TLS sessions. |
| 32 | * |
| 33 | * The API is designed such that it has no assumption about |
| 34 | * the type of transport it is running over. It may be a |
| 35 | * traditional TCP socket, or something else entirely. The |
| 36 | * only requirement is a full-duplex stream of some kind. |
| 37 | * |
| 38 | * <example> |
| 39 | * <title>Using TLS session objects</title> |
| 40 | * <programlisting> |
| 41 | * static ssize_t mysock_send(const char *buf, size_t len, |
| 42 | * void *opaque) |
| 43 | * { |
| 44 | * int fd = GPOINTER_TO_INT(opaque); |
| 45 | * |
| 46 | * return write(*fd, buf, len); |
| 47 | * } |
| 48 | * |
| 49 | * static ssize_t mysock_recv(const char *buf, size_t len, |
| 50 | * void *opaque) |
| 51 | * { |
| 52 | * int fd = GPOINTER_TO_INT(opaque); |
| 53 | * |
| 54 | * return read(*fd, buf, len); |
| 55 | * } |
| 56 | * |
| 57 | * static int mysock_run_tls(int sockfd, |
| 58 | * QCryptoTLSCreds *creds, |
| 59 | * Error **errp) |
| 60 | * { |
| 61 | * QCryptoTLSSession *sess; |
| 62 | * |
| 63 | * sess = qcrypto_tls_session_new(creds, |
| 64 | * "vnc.example.com", |
| 65 | * NULL, |
| 66 | * QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT, |
| 67 | * errp); |
| 68 | * if (sess == NULL) { |
| 69 | * return -1; |
| 70 | * } |
| 71 | * |
| 72 | * qcrypto_tls_session_set_callbacks(sess, |
| 73 | * mysock_send, |
| 74 | * mysock_recv |
| 75 | * GINT_TO_POINTER(fd)); |
| 76 | * |
| 77 | * while (1) { |
| 78 | * int ret = qcrypto_tls_session_handshake(sess, errp); |
| 79 | * |
| 80 | * if (ret < 0) { |
| 81 | * qcrypto_tls_session_free(sess); |
| 82 | * return -1; |
| 83 | * } |
| 84 | * |
| 85 | * switch(ret) { |
| 86 | * case QCRYPTO_TLS_HANDSHAKE_COMPLETE: |
| 87 | * if (qcrypto_tls_session_check_credentials(sess, errp) < )) { |
| 88 | * qcrypto_tls_session_free(sess); |
| 89 | * return -1; |
| 90 | * } |
| 91 | * goto done; |
| 92 | * case QCRYPTO_TLS_HANDSHAKE_RECVING: |
| 93 | * ...wait for GIO_IN event on fd... |
| 94 | * break; |
| 95 | * case QCRYPTO_TLS_HANDSHAKE_SENDING: |
| 96 | * ...wait for GIO_OUT event on fd... |
| 97 | * break; |
| 98 | * } |
| 99 | * } |
| 100 | * done: |
| 101 | * |
| 102 | * ....send/recv payload data on sess... |
| 103 | * |
| 104 | * qcrypto_tls_session_free(sess): |
| 105 | * } |
| 106 | * </programlisting> |
| 107 | * </example> |
| 108 | */ |
| 109 | |
| 110 | typedef struct QCryptoTLSSession QCryptoTLSSession; |
| 111 | |
| 112 | #define QCRYPTO_TLS_SESSION_ERR_BLOCK -2 |
| 113 | #define QCRYPTO_TLS_SESSION_PREMATURE_TERMINATION -3 |
| 114 | |
| 115 | /** |
| 116 | * qcrypto_tls_session_new: |
| 117 | * @creds: pointer to a TLS credentials object |
| 118 | * @hostname: optional hostname to validate |
| 119 | * @aclname: optional ACL to validate peer credentials against |
| 120 | * @endpoint: role of the TLS session, client or server |
| 121 | * @errp: pointer to a NULL-initialized error object |
| 122 | * |
| 123 | * Create a new TLS session object that will be used to |
| 124 | * negotiate a TLS session over an arbitrary data channel. |
| 125 | * The session object can operate as either the server or |
| 126 | * client, according to the value of the @endpoint argument. |
| 127 | * |
| 128 | * For clients, the @hostname parameter should hold the full |
| 129 | * unmodified hostname as requested by the user. This will |
| 130 | * be used to verify the against the hostname reported in |
| 131 | * the server's credentials (aka x509 certificate). |
| 132 | * |
| 133 | * The @aclname parameter (optionally) specifies the name |
| 134 | * of an access control list that will be used to validate |
| 135 | * the peer's credentials. For x509 credentials, the ACL |
| 136 | * will be matched against the CommonName shown in the peer's |
| 137 | * certificate. If the session is acting as a server, setting |
| 138 | * an ACL will require that the client provide a validate |
| 139 | * x509 client certificate. |
| 140 | * |
| 141 | * After creating the session object, the I/O callbacks |
| 142 | * must be set using the qcrypto_tls_session_set_callbacks() |
| 143 | * method. A TLS handshake sequence must then be completed |
| 144 | * using qcrypto_tls_session_handshake(), before payload |
| 145 | * data is permitted to be sent/received. |
| 146 | * |
| 147 | * The session object must be released by calling |
| 148 | * qcrypto_tls_session_free() when no longer required |
| 149 | * |
| 150 | * Returns: a TLS session object, or NULL on error. |
| 151 | */ |
| 152 | QCryptoTLSSession *qcrypto_tls_session_new(QCryptoTLSCreds *creds, |
| 153 | const char *hostname, |
| 154 | const char *aclname, |
| 155 | QCryptoTLSCredsEndpoint endpoint, |
| 156 | Error **errp); |
| 157 | |
| 158 | /** |
| 159 | * qcrypto_tls_session_free: |
| 160 | * @sess: the TLS session object |
| 161 | * |
| 162 | * Release all memory associated with the TLS session |
| 163 | * object previously allocated by qcrypto_tls_session_new() |
| 164 | */ |
| 165 | void qcrypto_tls_session_free(QCryptoTLSSession *sess); |
| 166 | |
| 167 | G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoTLSSession, qcrypto_tls_session_free) |
| 168 | |
| 169 | /** |
| 170 | * qcrypto_tls_session_require_thread_safety: |
| 171 | * @sess: the TLS session object |
| 172 | * |
| 173 | * Mark that this TLS session will require thread safety |
| 174 | * for concurrent I/O in both directions. This must be |
| 175 | * called before the handshake is performed. |
| 176 | * |
| 177 | * This will activate a workaround for GNUTLS thread |
| 178 | * safety issues, where appropriate for the negotiated |
| 179 | * TLS session parameters. |
| 180 | */ |
| 181 | void qcrypto_tls_session_require_thread_safety(QCryptoTLSSession *sess); |
| 182 | |
| 183 | /** |
| 184 | * qcrypto_tls_session_check_credentials: |
| 185 | * @sess: the TLS session object |
| 186 | * @errp: pointer to a NULL-initialized error object |
| 187 | * |
| 188 | * Validate the peer's credentials after a successful |
| 189 | * TLS handshake. It is an error to call this before |
| 190 | * qcrypto_tls_session_handshake() returns |
| 191 | * QCRYPTO_TLS_HANDSHAKE_COMPLETE |
| 192 | * |
| 193 | * Returns 0 if the credentials validated, -1 on error |
| 194 | */ |
| 195 | int qcrypto_tls_session_check_credentials(QCryptoTLSSession *sess, |
| 196 | Error **errp); |
| 197 | |
| 198 | /* |
| 199 | * These must return QCRYPTO_TLS_SESSION_ERR_BLOCK if the I/O |
| 200 | * would block, but on other errors, must fill 'errp' |
| 201 | */ |
| 202 | typedef ssize_t (*QCryptoTLSSessionWriteFunc)(const void *buf, |
| 203 | size_t len, |
| 204 | void *opaque, |
| 205 | Error **errp); |
| 206 | typedef ssize_t (*QCryptoTLSSessionReadFunc)(void *buf, |
| 207 | size_t len, |
| 208 | void *opaque, |
| 209 | Error **errp); |
| 210 | |
| 211 | /** |
| 212 | * qcrypto_tls_session_set_callbacks: |
| 213 | * @sess: the TLS session object |
| 214 | * @writeFunc: callback for sending data |
| 215 | * @readFunc: callback to receiving data |
| 216 | * @opaque: data to pass to callbacks |
| 217 | * |
| 218 | * Sets the callback functions that are to be used for sending |
| 219 | * and receiving data on the underlying data channel. Typically |
| 220 | * the callbacks to write/read to/from a TCP socket, but there |
| 221 | * is no assumption made about the type of channel used. |
| 222 | * |
| 223 | * The @writeFunc callback will be passed the encrypted |
| 224 | * data to send to the remote peer. |
| 225 | * |
| 226 | * The @readFunc callback will be passed a pointer to fill |
| 227 | * with encrypted data received from the remote peer |
| 228 | */ |
| 229 | void qcrypto_tls_session_set_callbacks(QCryptoTLSSession *sess, |
| 230 | QCryptoTLSSessionWriteFunc writeFunc, |
| 231 | QCryptoTLSSessionReadFunc readFunc, |
| 232 | void *opaque); |
| 233 | |
| 234 | /** |
| 235 | * qcrypto_tls_session_write: |
| 236 | * @sess: the TLS session object |
| 237 | * @buf: the plain text to send |
| 238 | * @len: the length of @buf |
| 239 | * @errp: pointer to hold returned error object |
| 240 | * |
| 241 | * Encrypt @len bytes of the data in @buf and send |
| 242 | * it to the remote peer using the callback previously |
| 243 | * registered with qcrypto_tls_session_set_callbacks() |
| 244 | * |
| 245 | * It is an error to call this before |
| 246 | * qcrypto_tls_session_handshake() returns |
| 247 | * QCRYPTO_TLS_HANDSHAKE_COMPLETE |
| 248 | * |
| 249 | * Returns: the number of bytes sent, |
| 250 | * or QCRYPTO_TLS_SESSION_ERR_BLOCK if the write would block, |
| 251 | * or -1 on error. |
| 252 | */ |
| 253 | ssize_t qcrypto_tls_session_write(QCryptoTLSSession *sess, |
| 254 | const char *buf, |
| 255 | size_t len, |
| 256 | Error **errp); |
| 257 | |
| 258 | /** |
| 259 | * qcrypto_tls_session_read: |
| 260 | * @sess: the TLS session object |
| 261 | * @buf: to fill with plain text received |
| 262 | * @len: the length of @buf |
| 263 | * @errp: pointer to hold returned error object |
| 264 | * |
| 265 | * Receive up to @len bytes of data from the remote peer |
| 266 | * using the callback previously registered with |
| 267 | * qcrypto_tls_session_set_callbacks(), decrypt it and |
| 268 | * store it in @buf. |
| 269 | * |
| 270 | * It is an error to call this before |
| 271 | * qcrypto_tls_session_handshake() returns |
| 272 | * QCRYPTO_TLS_HANDSHAKE_COMPLETE |
| 273 | * |
| 274 | * Returns: the number of bytes received, |
| 275 | * or QCRYPTO_TLS_SESSION_ERR_BLOCK if the receive would block, |
| 276 | * or QCRYPTO_TLS_SESSION_PREMATURE_TERMINATION if a premature termination |
| 277 | * is detected, or -1 on error. |
| 278 | */ |
| 279 | ssize_t qcrypto_tls_session_read(QCryptoTLSSession *sess, |
| 280 | char *buf, |
| 281 | size_t len, |
| 282 | Error **errp); |
| 283 | |
| 284 | /** |
| 285 | * qcrypto_tls_session_check_pending: |
| 286 | * @sess: the TLS session object |
| 287 | * |
| 288 | * Check if there are unread data in the TLS buffers that have |
| 289 | * already been read from the underlying data source. |
| 290 | * |
| 291 | * Returns: the number of bytes available or zero |
| 292 | */ |
| 293 | size_t qcrypto_tls_session_check_pending(QCryptoTLSSession *sess); |
| 294 | |
| 295 | /** |
| 296 | * qcrypto_tls_session_handshake: |
| 297 | * @sess: the TLS session object |
| 298 | * @errp: pointer to a NULL-initialized error object |
| 299 | * |
| 300 | * Start, or continue, a TLS handshake sequence. If |
| 301 | * the underlying data channel is non-blocking, then |
| 302 | * this method may return control before the handshake |
| 303 | * is complete. On non-blocking channels the |
| 304 | * return value determines whether the handshake |
| 305 | * has completed, or is waiting to send or receive |
| 306 | * data. In the latter cases, the caller should setup |
| 307 | * an event loop watch and call this method again |
| 308 | * once the underlying data channel is ready to read |
| 309 | * or write again |
| 310 | */ |
| 311 | int qcrypto_tls_session_handshake(QCryptoTLSSession *sess, |
| 312 | Error **errp); |
| 313 | |
| 314 | typedef enum { |
| 315 | QCRYPTO_TLS_HANDSHAKE_COMPLETE, |
| 316 | QCRYPTO_TLS_HANDSHAKE_SENDING, |
| 317 | QCRYPTO_TLS_HANDSHAKE_RECVING, |
| 318 | } QCryptoTLSSessionHandshakeStatus; |
| 319 | |
| 320 | typedef enum { |
| 321 | QCRYPTO_TLS_BYE_COMPLETE, |
| 322 | QCRYPTO_TLS_BYE_SENDING, |
| 323 | QCRYPTO_TLS_BYE_RECVING, |
| 324 | } QCryptoTLSSessionByeStatus; |
| 325 | |
| 326 | /** |
| 327 | * qcrypto_tls_session_bye: |
| 328 | * @session: the TLS session object |
| 329 | * @errp: pointer to a NULL-initialized error object |
| 330 | * |
| 331 | * Start, or continue, a TLS termination sequence. If the underlying |
| 332 | * data channel is non-blocking, then this method may return control |
| 333 | * before the termination is complete. The return value will indicate |
| 334 | * whether the termination has completed, or is waiting to send or |
| 335 | * receive data. In the latter cases, the caller should setup an event |
| 336 | * loop watch and call this method again once the underlying data |
| 337 | * channel is ready to read or write again. |
| 338 | */ |
| 339 | int |
| 340 | qcrypto_tls_session_bye(QCryptoTLSSession *session, Error **errp); |
| 341 | |
| 342 | /** |
| 343 | * qcrypto_tls_session_get_key_size: |
| 344 | * @sess: the TLS session object |
| 345 | * @errp: pointer to a NULL-initialized error object |
| 346 | * |
| 347 | * Check the size of the data channel encryption key |
| 348 | * |
| 349 | * Returns: the length in bytes of the encryption key |
| 350 | * or -1 on error |
| 351 | */ |
| 352 | int qcrypto_tls_session_get_key_size(QCryptoTLSSession *sess, |
| 353 | Error **errp); |
| 354 | |
| 355 | /** |
| 356 | * qcrypto_tls_session_get_peer_name: |
| 357 | * @sess: the TLS session object |
| 358 | * |
| 359 | * Get the identified name of the remote peer. If the |
| 360 | * TLS session was negotiated using x509 certificate |
| 361 | * credentials, this will return the CommonName from |
| 362 | * the peer's certificate. If no identified name is |
| 363 | * available it will return NULL. |
| 364 | * |
| 365 | * The returned data must be released with g_free() |
| 366 | * when no longer required. |
| 367 | * |
| 368 | * Returns: the peer's name or NULL. |
| 369 | */ |
| 370 | char *qcrypto_tls_session_get_peer_name(QCryptoTLSSession *sess); |
| 371 | |
| 372 | #endif /* QCRYPTO_TLSSESSION_H */ |