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 __FBSDID("$FreeBSD$"); 30 31 #include <sys/random.h> 32 33 #include "tpm20.h" 34 35 #define TPM_HARVEST_SIZE 16 36 /* 37 * Perform a harvest every 10 seconds. 38 * Since discrete TPMs are painfully slow 39 * we don't want to execute this too often 40 * as the chip is likely to be used by others too. 41 */ 42 #define TPM_HARVEST_INTERVAL 10 43 44 MALLOC_DEFINE(M_TPM20, "tpm_buffer", "buffer for tpm 2.0 driver"); 45 46 static void tpm20_discard_buffer(void *arg); 47 #ifdef TPM_HARVEST 48 static void tpm20_harvest(void *arg, int unused); 49 #endif 50 static int tpm20_save_state(device_t dev, bool suspend); 51 52 static d_open_t tpm20_open; 53 static d_close_t tpm20_close; 54 static d_read_t tpm20_read; 55 static d_write_t tpm20_write; 56 static d_ioctl_t tpm20_ioctl; 57 58 static struct cdevsw tpm20_cdevsw = { 59 .d_version = D_VERSION, 60 .d_open = tpm20_open, 61 .d_close = tpm20_close, 62 .d_read = tpm20_read, 63 .d_write = tpm20_write, 64 .d_ioctl = tpm20_ioctl, 65 .d_name = "tpm20", 66 }; 67 68 int 69 tpm20_read(struct cdev *dev, struct uio *uio, int flags) 70 { 71 struct tpm_sc *sc; 72 size_t bytes_to_transfer; 73 int result = 0; 74 75 sc = (struct tpm_sc *)dev->si_drv1; 76 77 callout_stop(&sc->discard_buffer_callout); 78 sx_xlock(&sc->dev_lock); 79 if (sc->owner_tid != uio->uio_td->td_tid) { 80 sx_xunlock(&sc->dev_lock); 81 return (EPERM); 82 } 83 84 bytes_to_transfer = MIN(sc->pending_data_length, uio->uio_resid); 85 if (bytes_to_transfer > 0) { 86 result = uiomove((caddr_t) sc->buf, bytes_to_transfer, uio); 87 memset(sc->buf, 0, TPM_BUFSIZE); 88 sc->pending_data_length = 0; 89 cv_signal(&sc->buf_cv); 90 } else { 91 result = ETIMEDOUT; 92 } 93 94 sx_xunlock(&sc->dev_lock); 95 96 return (result); 97 } 98 99 int 100 tpm20_write(struct cdev *dev, struct uio *uio, int flags) 101 { 102 struct tpm_sc *sc; 103 size_t byte_count; 104 int result = 0; 105 106 sc = (struct tpm_sc *)dev->si_drv1; 107 108 byte_count = uio->uio_resid; 109 if (byte_count < TPM_HEADER_SIZE) { 110 device_printf(sc->dev, 111 "Requested transfer is too small\n"); 112 return (EINVAL); 113 } 114 115 if (byte_count > TPM_BUFSIZE) { 116 device_printf(sc->dev, 117 "Requested transfer is too large\n"); 118 return (E2BIG); 119 } 120 121 sx_xlock(&sc->dev_lock); 122 123 while (sc->pending_data_length != 0) 124 cv_wait(&sc->buf_cv, &sc->dev_lock); 125 126 result = uiomove(sc->buf, byte_count, uio); 127 if (result != 0) { 128 sx_xunlock(&sc->dev_lock); 129 return (result); 130 } 131 132 result = sc->transmit(sc, byte_count); 133 134 if (result == 0) { 135 callout_reset(&sc->discard_buffer_callout, 136 TPM_READ_TIMEOUT / tick, tpm20_discard_buffer, sc); 137 sc->owner_tid = uio->uio_td->td_tid; 138 } 139 140 sx_xunlock(&sc->dev_lock); 141 return (result); 142 } 143 144 static void 145 tpm20_discard_buffer(void *arg) 146 { 147 struct tpm_sc *sc; 148 149 sc = (struct tpm_sc *)arg; 150 if (callout_pending(&sc->discard_buffer_callout)) 151 return; 152 153 sx_xlock(&sc->dev_lock); 154 155 memset(sc->buf, 0, TPM_BUFSIZE); 156 sc->pending_data_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; 196 197 make_dev_args_init(&args); 198 args.mda_devsw = &tpm20_cdevsw; 199 args.mda_uid = UID_ROOT; 200 args.mda_gid = GID_WHEEL; 201 args.mda_mode = TPM_CDEV_PERM_FLAG; 202 args.mda_si_drv1 = sc; 203 result = make_dev_s(&args, &sc->sc_cdev, TPM_CDEV_NAME); 204 if (result != 0) 205 tpm20_release(sc); 206 207 #ifdef TPM_HARVEST 208 TIMEOUT_TASK_INIT(taskqueue_thread, &sc->harvest_task, 0, 209 tpm20_harvest, sc); 210 taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task, 0); 211 #endif 212 213 return (result); 214 215 } 216 217 void 218 tpm20_release(struct tpm_sc *sc) 219 { 220 221 #ifdef TPM_HARVEST 222 if (device_is_attached(sc->dev)) 223 taskqueue_drain_timeout(taskqueue_thread, &sc->harvest_task); 224 #endif 225 226 if (sc->buf != NULL) 227 free(sc->buf, M_TPM20); 228 229 sx_destroy(&sc->dev_lock); 230 cv_destroy(&sc->buf_cv); 231 if (sc->sc_cdev != NULL) 232 destroy_dev(sc->sc_cdev); 233 } 234 235 int 236 tpm20_suspend(device_t dev) 237 { 238 return (tpm20_save_state(dev, true)); 239 } 240 241 int 242 tpm20_shutdown(device_t dev) 243 { 244 return (tpm20_save_state(dev, false)); 245 } 246 247 #ifdef TPM_HARVEST 248 /* 249 * Get TPM_HARVEST_SIZE random bytes and add them 250 * into system entropy pool. 251 */ 252 static void 253 tpm20_harvest(void *arg, int unused) 254 { 255 struct tpm_sc *sc; 256 unsigned char entropy[TPM_HARVEST_SIZE]; 257 uint16_t entropy_size; 258 int result; 259 uint8_t cmd[] = { 260 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/ 261 0x00, 0x00, 0x00, 0x0c, /* cmd length */ 262 0x00, 0x00, 0x01, 0x7b, /* cmd TPM_CC_GetRandom */ 263 0x00, TPM_HARVEST_SIZE /* number of bytes requested */ 264 }; 265 266 sc = arg; 267 sx_xlock(&sc->dev_lock); 268 while (sc->pending_data_length != 0) 269 cv_wait(&sc->buf_cv, &sc->dev_lock); 270 271 memcpy(sc->buf, cmd, sizeof(cmd)); 272 result = sc->transmit(sc, sizeof(cmd)); 273 if (result != 0) { 274 sx_xunlock(&sc->dev_lock); 275 return; 276 } 277 278 /* Ignore response size */ 279 sc->pending_data_length = 0; 280 281 /* The number of random bytes we got is placed right after the header */ 282 entropy_size = (uint16_t) sc->buf[TPM_HEADER_SIZE + 1]; 283 if (entropy_size > 0) { 284 entropy_size = MIN(entropy_size, TPM_HARVEST_SIZE); 285 memcpy(entropy, 286 sc->buf + TPM_HEADER_SIZE + sizeof(uint16_t), 287 entropy_size); 288 } 289 290 sx_xunlock(&sc->dev_lock); 291 if (entropy_size > 0) 292 random_harvest_queue(entropy, entropy_size, RANDOM_PURE_TPM); 293 294 taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task, 295 hz * TPM_HARVEST_INTERVAL); 296 } 297 #endif /* TPM_HARVEST */ 298 299 static int 300 tpm20_save_state(device_t dev, bool suspend) 301 { 302 struct tpm_sc *sc; 303 uint8_t save_cmd[] = { 304 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/ 305 0x00, 0x00, 0x00, 0x0C, /* cmd length */ 306 0x00, 0x00, 0x01, 0x45, /* cmd TPM_CC_Shutdown */ 307 0x00, 0x00 /* TPM_SU_STATE */ 308 }; 309 310 sc = device_get_softc(dev); 311 312 /* 313 * Inform the TPM whether we are going to suspend or reboot/shutdown. 314 */ 315 if (suspend) 316 save_cmd[11] = 1; /* TPM_SU_STATE */ 317 318 if (sc == NULL || sc->buf == NULL) 319 return (0); 320 321 sx_xlock(&sc->dev_lock); 322 323 memcpy(sc->buf, save_cmd, sizeof(save_cmd)); 324 sc->transmit(sc, sizeof(save_cmd)); 325 326 sx_xunlock(&sc->dev_lock); 327 328 return (0); 329 } 330 331 int32_t 332 tpm20_get_timeout(uint32_t command) 333 { 334 int32_t timeout; 335 336 switch (command) { 337 case TPM_CC_CreatePrimary: 338 case TPM_CC_Create: 339 case TPM_CC_CreateLoaded: 340 timeout = TPM_TIMEOUT_LONG; 341 break; 342 case TPM_CC_SequenceComplete: 343 case TPM_CC_Startup: 344 case TPM_CC_SequenceUpdate: 345 case TPM_CC_GetCapability: 346 case TPM_CC_PCR_Extend: 347 case TPM_CC_EventSequenceComplete: 348 case TPM_CC_HashSequenceStart: 349 timeout = TPM_TIMEOUT_C; 350 break; 351 default: 352 timeout = TPM_TIMEOUT_B; 353 break; 354 } 355 return timeout; 356 } 357