1 /*- 2 * Copyright (c) 2018 Stormshield. 3 * Copyright (c) 2018 Semihalf. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 19 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 23 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 24 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25 * POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 #include <sys/random.h> 30 31 #include "tpm20.h" 32 33 #define TPM_HARVEST_SIZE 16 34 /* 35 * Perform a harvest every 10 seconds. 36 * Since discrete TPMs are painfully slow 37 * we don't want to execute this too often 38 * as the chip is likely to be used by others too. 39 */ 40 #define TPM_HARVEST_INTERVAL 10 41 42 MALLOC_DEFINE(M_TPM20, "tpm_buffer", "buffer for tpm 2.0 driver"); 43 44 static void tpm20_discard_buffer(void *arg); 45 #ifdef TPM_HARVEST 46 static void tpm20_harvest(void *arg, int unused); 47 #endif 48 static int tpm20_save_state(device_t dev, bool suspend); 49 50 static d_open_t tpm20_open; 51 static d_close_t tpm20_close; 52 static d_read_t tpm20_read; 53 static d_write_t tpm20_write; 54 static d_ioctl_t tpm20_ioctl; 55 56 static struct cdevsw tpm20_cdevsw = { 57 .d_version = D_VERSION, 58 .d_open = tpm20_open, 59 .d_close = tpm20_close, 60 .d_read = tpm20_read, 61 .d_write = tpm20_write, 62 .d_ioctl = tpm20_ioctl, 63 .d_name = "tpm20", 64 }; 65 66 int 67 tpm20_read(struct cdev *dev, struct uio *uio, int flags) 68 { 69 struct tpm_sc *sc; 70 size_t bytes_to_transfer; 71 size_t offset; 72 int result = 0; 73 74 sc = (struct tpm_sc *)dev->si_drv1; 75 76 callout_stop(&sc->discard_buffer_callout); 77 sx_xlock(&sc->dev_lock); 78 if (sc->owner_tid != uio->uio_td->td_tid) { 79 sx_xunlock(&sc->dev_lock); 80 return (EPERM); 81 } 82 83 bytes_to_transfer = MIN(sc->pending_data_length, uio->uio_resid); 84 offset = sc->total_length - sc->pending_data_length; 85 if (bytes_to_transfer > 0) { 86 result = uiomove((caddr_t) sc->buf + offset, bytes_to_transfer, uio); 87 sc->pending_data_length -= bytes_to_transfer; 88 cv_signal(&sc->buf_cv); 89 } else { 90 result = ETIMEDOUT; 91 } 92 93 sx_xunlock(&sc->dev_lock); 94 95 return (result); 96 } 97 98 int 99 tpm20_write(struct cdev *dev, struct uio *uio, int flags) 100 { 101 struct tpm_sc *sc; 102 size_t byte_count; 103 int result = 0; 104 105 sc = (struct tpm_sc *)dev->si_drv1; 106 107 byte_count = uio->uio_resid; 108 if (byte_count < TPM_HEADER_SIZE) { 109 device_printf(sc->dev, 110 "Requested transfer is too small\n"); 111 return (EINVAL); 112 } 113 114 if (byte_count > TPM_BUFSIZE) { 115 device_printf(sc->dev, 116 "Requested transfer is too large\n"); 117 return (E2BIG); 118 } 119 120 sx_xlock(&sc->dev_lock); 121 122 while (sc->pending_data_length != 0) 123 cv_wait(&sc->buf_cv, &sc->dev_lock); 124 125 result = uiomove(sc->buf, byte_count, uio); 126 if (result != 0) { 127 sx_xunlock(&sc->dev_lock); 128 return (result); 129 } 130 131 result = TPM_TRANSMIT(sc->dev, byte_count); 132 133 if (result == 0) { 134 callout_reset(&sc->discard_buffer_callout, 135 TPM_READ_TIMEOUT / tick, tpm20_discard_buffer, sc); 136 sc->owner_tid = uio->uio_td->td_tid; 137 } 138 139 sx_xunlock(&sc->dev_lock); 140 return (result); 141 } 142 143 static void 144 tpm20_discard_buffer(void *arg) 145 { 146 struct tpm_sc *sc; 147 148 sc = (struct tpm_sc *)arg; 149 if (callout_pending(&sc->discard_buffer_callout)) 150 return; 151 152 sx_xlock(&sc->dev_lock); 153 154 memset(sc->buf, 0, TPM_BUFSIZE); 155 sc->pending_data_length = 0; 156 sc->total_length = 0; 157 158 cv_signal(&sc->buf_cv); 159 sx_xunlock(&sc->dev_lock); 160 161 device_printf(sc->dev, 162 "User failed to read buffer in time\n"); 163 } 164 165 int 166 tpm20_open(struct cdev *dev, int flag, int mode, struct thread *td) 167 { 168 169 return (0); 170 } 171 172 int 173 tpm20_close(struct cdev *dev, int flag, int mode, struct thread *td) 174 { 175 176 return (0); 177 } 178 179 int 180 tpm20_ioctl(struct cdev *dev, u_long cmd, caddr_t data, 181 int flags, struct thread *td) 182 { 183 184 return (ENOTTY); 185 } 186 187 int 188 tpm20_init(struct tpm_sc *sc) 189 { 190 struct make_dev_args args; 191 int result; 192 193 cv_init(&sc->buf_cv, "TPM buffer cv"); 194 callout_init(&sc->discard_buffer_callout, 1); 195 sc->pending_data_length = 0; 196 sc->total_length = 0; 197 198 make_dev_args_init(&args); 199 args.mda_devsw = &tpm20_cdevsw; 200 args.mda_uid = UID_ROOT; 201 args.mda_gid = GID_WHEEL; 202 args.mda_mode = TPM_CDEV_PERM_FLAG; 203 args.mda_si_drv1 = sc; 204 result = make_dev_s(&args, &sc->sc_cdev, TPM_CDEV_NAME); 205 if (result != 0) 206 tpm20_release(sc); 207 208 #ifdef TPM_HARVEST 209 random_harvest_register_source(RANDOM_PURE_TPM); 210 TIMEOUT_TASK_INIT(taskqueue_thread, &sc->harvest_task, 0, 211 tpm20_harvest, sc); 212 taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task, 0); 213 #endif 214 215 return (result); 216 217 } 218 219 void 220 tpm20_release(struct tpm_sc *sc) 221 { 222 223 #ifdef TPM_HARVEST 224 if (device_is_attached(sc->dev)) 225 taskqueue_drain_timeout(taskqueue_thread, &sc->harvest_task); 226 random_harvest_deregister_source(RANDOM_PURE_TPM); 227 #endif 228 229 if (sc->buf != NULL) 230 free(sc->buf, M_TPM20); 231 232 sx_destroy(&sc->dev_lock); 233 cv_destroy(&sc->buf_cv); 234 if (sc->sc_cdev != NULL) 235 destroy_dev(sc->sc_cdev); 236 } 237 238 int 239 tpm20_suspend(device_t dev) 240 { 241 return (tpm20_save_state(dev, true)); 242 } 243 244 int 245 tpm20_shutdown(device_t dev) 246 { 247 return (tpm20_save_state(dev, false)); 248 } 249 250 #ifdef TPM_HARVEST 251 /* 252 * Get TPM_HARVEST_SIZE random bytes and add them 253 * into system entropy pool. 254 */ 255 static void 256 tpm20_harvest(void *arg, int unused) 257 { 258 struct tpm_sc *sc; 259 unsigned char entropy[TPM_HARVEST_SIZE]; 260 uint16_t entropy_size; 261 int result; 262 uint8_t cmd[] = { 263 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/ 264 0x00, 0x00, 0x00, 0x0c, /* cmd length */ 265 0x00, 0x00, 0x01, 0x7b, /* cmd TPM_CC_GetRandom */ 266 0x00, TPM_HARVEST_SIZE /* number of bytes requested */ 267 }; 268 269 sc = arg; 270 sx_xlock(&sc->dev_lock); 271 while (sc->pending_data_length != 0) 272 cv_wait(&sc->buf_cv, &sc->dev_lock); 273 274 memcpy(sc->buf, cmd, sizeof(cmd)); 275 result = TPM_TRANSMIT(sc->dev, sizeof(cmd)); 276 if (result != 0) { 277 sx_xunlock(&sc->dev_lock); 278 return; 279 } 280 281 /* Ignore response size */ 282 sc->pending_data_length = 0; 283 sc->total_length = 0; 284 285 /* The number of random bytes we got is placed right after the header */ 286 entropy_size = (uint16_t) sc->buf[TPM_HEADER_SIZE + 1]; 287 if (entropy_size > 0) { 288 entropy_size = MIN(entropy_size, TPM_HARVEST_SIZE); 289 memcpy(entropy, 290 sc->buf + TPM_HEADER_SIZE + sizeof(uint16_t), 291 entropy_size); 292 } 293 294 sx_xunlock(&sc->dev_lock); 295 if (entropy_size > 0) 296 random_harvest_queue(entropy, entropy_size, RANDOM_PURE_TPM); 297 298 taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task, 299 hz * TPM_HARVEST_INTERVAL); 300 } 301 #endif /* TPM_HARVEST */ 302 303 static int 304 tpm20_save_state(device_t dev, bool suspend) 305 { 306 struct tpm_sc *sc; 307 uint8_t save_cmd[] = { 308 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/ 309 0x00, 0x00, 0x00, 0x0C, /* cmd length */ 310 0x00, 0x00, 0x01, 0x45, /* cmd TPM_CC_Shutdown */ 311 0x00, 0x00 /* TPM_SU_STATE */ 312 }; 313 314 sc = device_get_softc(dev); 315 316 /* 317 * Inform the TPM whether we are going to suspend or reboot/shutdown. 318 */ 319 if (suspend) 320 save_cmd[11] = 1; /* TPM_SU_STATE */ 321 322 if (sc == NULL || sc->buf == NULL) 323 return (0); 324 325 sx_xlock(&sc->dev_lock); 326 327 memcpy(sc->buf, save_cmd, sizeof(save_cmd)); 328 TPM_TRANSMIT(sc->dev, sizeof(save_cmd)); 329 330 sx_xunlock(&sc->dev_lock); 331 332 return (0); 333 } 334 335 int32_t 336 tpm20_get_timeout(uint32_t command) 337 { 338 int32_t timeout; 339 340 switch (command) { 341 case TPM_CC_CreatePrimary: 342 case TPM_CC_Create: 343 case TPM_CC_CreateLoaded: 344 timeout = TPM_TIMEOUT_LONG; 345 break; 346 case TPM_CC_SequenceComplete: 347 case TPM_CC_Startup: 348 case TPM_CC_SequenceUpdate: 349 case TPM_CC_GetCapability: 350 case TPM_CC_PCR_Extend: 351 case TPM_CC_EventSequenceComplete: 352 case TPM_CC_HashSequenceStart: 353 timeout = TPM_TIMEOUT_C; 354 break; 355 default: 356 timeout = TPM_TIMEOUT_B; 357 break; 358 } 359 return timeout; 360 } 361