| 1 | /* |
| 2 | * passthrough TPM driver |
| 3 | * |
| 4 | * Copyright (c) 2010 - 2013 IBM Corporation |
| 5 | * Authors: |
| 6 | * Stefan Berger <stefanb@us.ibm.com> |
| 7 | * |
| 8 | * Copyright (C) 2011 IAIK, Graz University of Technology |
| 9 | * Author: Andreas Niederl |
| 10 | * |
| 11 | * This library is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU Lesser General Public |
| 13 | * License as published by the Free Software Foundation; either |
| 14 | * version 2.1 of the License, or (at your option) any later version. |
| 15 | * |
| 16 | * This library is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 19 | * Lesser General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU Lesser General Public |
| 22 | * License along with this library; if not, see <http://www.gnu.org/licenses/> |
| 23 | */ |
| 24 | |
| 25 | #include "qemu/osdep.h" |
| 26 | #include "qemu/error-report.h" |
| 27 | #include "qemu/module.h" |
| 28 | #include "qemu/sockets.h" |
| 29 | #include "system/tpm_backend.h" |
| 30 | #include "system/tpm_util.h" |
| 31 | #include "tpm_int.h" |
| 32 | #include "qapi/clone-visitor.h" |
| 33 | #include "qapi/qapi-visit-tpm.h" |
| 34 | #include "trace.h" |
| 35 | #include "qom/object.h" |
| 36 | |
| 37 | #define TYPE_TPM_PASSTHROUGH "tpm-passthrough" |
| 38 | OBJECT_DECLARE_SIMPLE_TYPE(TPMPassthruState, TPM_PASSTHROUGH) |
| 39 | |
| 40 | /* data structures */ |
| 41 | struct TPMPassthruState { |
| 42 | TPMBackend parent; |
| 43 | |
| 44 | TPMPassthroughOptions *options; |
| 45 | const char *tpm_dev; |
| 46 | int tpm_fd; |
| 47 | bool tpm_executing; |
| 48 | bool tpm_op_canceled; |
| 49 | int cancel_fd; |
| 50 | |
| 51 | TPMVersion tpm_version; |
| 52 | size_t tpm_buffersize; |
| 53 | }; |
| 54 | |
| 55 | |
| 56 | #define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0" |
| 57 | |
| 58 | /* functions */ |
| 59 | |
| 60 | static void tpm_passthrough_cancel_cmd(TPMBackend *tb); |
| 61 | |
| 62 | static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len) |
| 63 | { |
| 64 | int ret; |
| 65 | reread: |
| 66 | ret = read(fd, buf, len); |
| 67 | if (ret < 0) { |
| 68 | if (errno != EINTR && errno != EAGAIN) { |
| 69 | return -1; |
| 70 | } |
| 71 | goto reread; |
| 72 | } |
| 73 | return ret; |
| 74 | } |
| 75 | |
| 76 | static void tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt, |
| 77 | const uint8_t *in, uint32_t in_len, |
| 78 | uint8_t *out, uint32_t out_len, |
| 79 | bool *selftest_done, Error **errp) |
| 80 | { |
| 81 | ssize_t ret; |
| 82 | bool is_selftest; |
| 83 | |
| 84 | /* FIXME: protect shared variables or use other sync mechanism */ |
| 85 | tpm_pt->tpm_op_canceled = false; |
| 86 | tpm_pt->tpm_executing = true; |
| 87 | *selftest_done = false; |
| 88 | |
| 89 | is_selftest = tpm_util_is_selftest(in, in_len); |
| 90 | |
| 91 | ret = qemu_write_full(tpm_pt->tpm_fd, in, in_len); |
| 92 | if (ret != in_len) { |
| 93 | if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) { |
| 94 | error_setg_errno(errp, errno, "tpm_passthrough: error while " |
| 95 | "transmitting data to TPM"); |
| 96 | } |
| 97 | goto err_exit; |
| 98 | } |
| 99 | |
| 100 | tpm_pt->tpm_executing = false; |
| 101 | |
| 102 | ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len); |
| 103 | if (ret < 0) { |
| 104 | if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) { |
| 105 | error_setg_errno(errp, errno, "tpm_passthrough: error while " |
| 106 | "reading data from TPM"); |
| 107 | } |
| 108 | } else if (ret < sizeof(struct tpm_resp_hdr) || |
| 109 | tpm_cmd_get_size(out) != ret) { |
| 110 | ret = -1; |
| 111 | error_setg_errno(errp, errno, "tpm_passthrough: received invalid " |
| 112 | "response packet from TPM"); |
| 113 | } |
| 114 | |
| 115 | if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) { |
| 116 | *selftest_done = tpm_cmd_get_errcode(out) == 0; |
| 117 | } |
| 118 | |
| 119 | err_exit: |
| 120 | if (ret < 0) { |
| 121 | tpm_util_write_fatal_error_response(out, out_len); |
| 122 | } |
| 123 | |
| 124 | tpm_pt->tpm_executing = false; |
| 125 | } |
| 126 | |
| 127 | static void tpm_passthrough_handle_request(TPMBackend *tb, TPMBackendCmd *cmd, |
| 128 | Error **errp) |
| 129 | { |
| 130 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); |
| 131 | |
| 132 | trace_tpm_passthrough_handle_request(cmd); |
| 133 | |
| 134 | tpm_passthrough_unix_tx_bufs(tpm_pt, cmd->in, cmd->in_len, |
| 135 | cmd->out, cmd->out_len, &cmd->selftest_done, |
| 136 | errp); |
| 137 | } |
| 138 | |
| 139 | static void tpm_passthrough_reset(TPMBackend *tb) |
| 140 | { |
| 141 | trace_tpm_passthrough_reset(); |
| 142 | |
| 143 | tpm_passthrough_cancel_cmd(tb); |
| 144 | } |
| 145 | |
| 146 | static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb) |
| 147 | { |
| 148 | return false; |
| 149 | } |
| 150 | |
| 151 | static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb, |
| 152 | uint8_t locty) |
| 153 | { |
| 154 | /* only a TPM 2.0 will support this */ |
| 155 | return 0; |
| 156 | } |
| 157 | |
| 158 | static void tpm_passthrough_cancel_cmd(TPMBackend *tb) |
| 159 | { |
| 160 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); |
| 161 | int n; |
| 162 | |
| 163 | /* |
| 164 | * As of Linux 3.7 the tpm_tis driver does not properly cancel |
| 165 | * commands on all TPM manufacturers' TPMs. |
| 166 | * Only cancel if we're busy so we don't cancel someone else's |
| 167 | * command, e.g., a command executed on the host. |
| 168 | */ |
| 169 | if (tpm_pt->tpm_executing) { |
| 170 | if (tpm_pt->cancel_fd >= 0) { |
| 171 | tpm_pt->tpm_op_canceled = true; |
| 172 | n = write(tpm_pt->cancel_fd, "-", 1); |
| 173 | if (n != 1) { |
| 174 | error_report("Canceling TPM command failed: %s", |
| 175 | strerror(errno)); |
| 176 | } |
| 177 | } else { |
| 178 | error_report("Cannot cancel TPM command due to missing " |
| 179 | "TPM sysfs cancel entry"); |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | |
| 184 | static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb) |
| 185 | { |
| 186 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); |
| 187 | |
| 188 | return tpm_pt->tpm_version; |
| 189 | } |
| 190 | |
| 191 | static size_t tpm_passthrough_get_buffer_size(TPMBackend *tb) |
| 192 | { |
| 193 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); |
| 194 | int ret; |
| 195 | |
| 196 | ret = tpm_util_get_buffer_size(tpm_pt->tpm_fd, tpm_pt->tpm_version, |
| 197 | &tpm_pt->tpm_buffersize); |
| 198 | if (ret < 0) { |
| 199 | tpm_pt->tpm_buffersize = 4096; |
| 200 | } |
| 201 | return tpm_pt->tpm_buffersize; |
| 202 | } |
| 203 | |
| 204 | /* |
| 205 | * Unless path or file descriptor set has been provided by user, |
| 206 | * determine the sysfs cancel file following kernel documentation |
| 207 | * in Documentation/ABI/stable/sysfs-class-tpm. |
| 208 | * From /dev/tpm0 create /sys/class/tpm/tpm0/device/cancel |
| 209 | * before 4.0: /sys/class/misc/tpm0/device/cancel |
| 210 | */ |
| 211 | static int tpm_passthrough_open_sysfs_cancel(TPMPassthruState *tpm_pt) |
| 212 | { |
| 213 | int fd = -1; |
| 214 | const char *dev; |
| 215 | char path[PATH_MAX]; |
| 216 | |
| 217 | if (tpm_pt->options->cancel_path) { |
| 218 | fd = qemu_open_old(tpm_pt->options->cancel_path, O_WRONLY); |
| 219 | if (fd < 0) { |
| 220 | error_report("tpm_passthrough: Could not open TPM cancel path: %s", |
| 221 | strerror(errno)); |
| 222 | } |
| 223 | return fd; |
| 224 | } |
| 225 | |
| 226 | dev = strrchr(tpm_pt->tpm_dev, '/'); |
| 227 | if (!dev) { |
| 228 | error_report("tpm_passthrough: Bad TPM device path %s", |
| 229 | tpm_pt->tpm_dev); |
| 230 | return -1; |
| 231 | } |
| 232 | |
| 233 | dev++; |
| 234 | if (snprintf(path, sizeof(path), "/sys/class/tpm/%s/device/cancel", |
| 235 | dev) < sizeof(path)) { |
| 236 | fd = qemu_open_old(path, O_WRONLY); |
| 237 | if (fd < 0) { |
| 238 | if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel", |
| 239 | dev) < sizeof(path)) { |
| 240 | fd = qemu_open_old(path, O_WRONLY); |
| 241 | } |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | if (fd < 0) { |
| 246 | error_report("tpm_passthrough: Could not guess TPM cancel path"); |
| 247 | } else { |
| 248 | tpm_pt->options->cancel_path = g_strdup(path); |
| 249 | } |
| 250 | |
| 251 | return fd; |
| 252 | } |
| 253 | |
| 254 | static int |
| 255 | tpm_passthrough_handle_device_opts(TPMPassthruState *tpm_pt, QemuOpts *opts) |
| 256 | { |
| 257 | const char *value; |
| 258 | |
| 259 | value = qemu_opt_get(opts, "cancel-path"); |
| 260 | if (value) { |
| 261 | tpm_pt->options->cancel_path = g_strdup(value); |
| 262 | } |
| 263 | |
| 264 | value = qemu_opt_get(opts, "path"); |
| 265 | if (value) { |
| 266 | tpm_pt->options->path = g_strdup(value); |
| 267 | } |
| 268 | |
| 269 | tpm_pt->tpm_dev = value ? value : TPM_PASSTHROUGH_DEFAULT_DEVICE; |
| 270 | tpm_pt->tpm_fd = qemu_open_old(tpm_pt->tpm_dev, O_RDWR); |
| 271 | if (tpm_pt->tpm_fd < 0) { |
| 272 | error_report("Cannot access TPM device using '%s': %s", |
| 273 | tpm_pt->tpm_dev, strerror(errno)); |
| 274 | return -1; |
| 275 | } |
| 276 | |
| 277 | if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) { |
| 278 | error_report("'%s' is not a TPM device.", |
| 279 | tpm_pt->tpm_dev); |
| 280 | return -1; |
| 281 | } |
| 282 | |
| 283 | tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tpm_pt); |
| 284 | if (tpm_pt->cancel_fd < 0) { |
| 285 | return -1; |
| 286 | } |
| 287 | |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | static TPMBackend *tpm_passthrough_create(QemuOpts *opts) |
| 292 | { |
| 293 | Object *obj = object_new(TYPE_TPM_PASSTHROUGH); |
| 294 | |
| 295 | if (tpm_passthrough_handle_device_opts(TPM_PASSTHROUGH(obj), opts)) { |
| 296 | object_unref(obj); |
| 297 | return NULL; |
| 298 | } |
| 299 | |
| 300 | return TPM_BACKEND(obj); |
| 301 | } |
| 302 | |
| 303 | static int tpm_passthrough_startup_tpm(TPMBackend *tb, size_t buffersize) |
| 304 | { |
| 305 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); |
| 306 | |
| 307 | if (buffersize && buffersize < tpm_pt->tpm_buffersize) { |
| 308 | error_report("Requested buffer size of %zu is smaller than host TPM's " |
| 309 | "fixed buffer size of %zu", |
| 310 | buffersize, tpm_pt->tpm_buffersize); |
| 311 | return -1; |
| 312 | } |
| 313 | |
| 314 | return 0; |
| 315 | } |
| 316 | |
| 317 | static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb) |
| 318 | { |
| 319 | TpmTypeOptions *options = g_new0(TpmTypeOptions, 1); |
| 320 | |
| 321 | options->type = TPM_TYPE_PASSTHROUGH; |
| 322 | options->u.passthrough.data = QAPI_CLONE(TPMPassthroughOptions, |
| 323 | TPM_PASSTHROUGH(tb)->options); |
| 324 | |
| 325 | return options; |
| 326 | } |
| 327 | |
| 328 | static const QemuOptDesc tpm_passthrough_cmdline_opts[] = { |
| 329 | TPM_STANDARD_CMDLINE_OPTS, |
| 330 | { |
| 331 | .name = "cancel-path", |
| 332 | .type = QEMU_OPT_STRING, |
| 333 | .help = "Sysfs file entry for canceling TPM commands", |
| 334 | }, |
| 335 | { |
| 336 | .name = "path", |
| 337 | .type = QEMU_OPT_STRING, |
| 338 | .help = "Path to TPM device on the host", |
| 339 | }, |
| 340 | { /* end of list */ }, |
| 341 | }; |
| 342 | |
| 343 | static void tpm_passthrough_inst_init(Object *obj) |
| 344 | { |
| 345 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj); |
| 346 | |
| 347 | tpm_pt->options = g_new0(TPMPassthroughOptions, 1); |
| 348 | tpm_pt->tpm_fd = -1; |
| 349 | tpm_pt->cancel_fd = -1; |
| 350 | } |
| 351 | |
| 352 | static void tpm_passthrough_inst_finalize(Object *obj) |
| 353 | { |
| 354 | TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj); |
| 355 | |
| 356 | tpm_passthrough_cancel_cmd(TPM_BACKEND(obj)); |
| 357 | |
| 358 | if (tpm_pt->tpm_fd >= 0) { |
| 359 | qemu_close(tpm_pt->tpm_fd); |
| 360 | } |
| 361 | if (tpm_pt->cancel_fd >= 0) { |
| 362 | qemu_close(tpm_pt->cancel_fd); |
| 363 | } |
| 364 | qapi_free_TPMPassthroughOptions(tpm_pt->options); |
| 365 | } |
| 366 | |
| 367 | static void tpm_passthrough_class_init(ObjectClass *klass, const void *data) |
| 368 | { |
| 369 | TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass); |
| 370 | |
| 371 | tbc->type = TPM_TYPE_PASSTHROUGH; |
| 372 | tbc->opts = tpm_passthrough_cmdline_opts; |
| 373 | tbc->desc = "Passthrough TPM backend driver"; |
| 374 | tbc->create = tpm_passthrough_create; |
| 375 | tbc->startup_tpm = tpm_passthrough_startup_tpm; |
| 376 | tbc->reset = tpm_passthrough_reset; |
| 377 | tbc->cancel_cmd = tpm_passthrough_cancel_cmd; |
| 378 | tbc->get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag; |
| 379 | tbc->reset_tpm_established_flag = |
| 380 | tpm_passthrough_reset_tpm_established_flag; |
| 381 | tbc->get_tpm_version = tpm_passthrough_get_tpm_version; |
| 382 | tbc->get_buffer_size = tpm_passthrough_get_buffer_size; |
| 383 | tbc->get_tpm_options = tpm_passthrough_get_tpm_options; |
| 384 | tbc->handle_request = tpm_passthrough_handle_request; |
| 385 | } |
| 386 | |
| 387 | static const TypeInfo tpm_passthrough_info = { |
| 388 | .name = TYPE_TPM_PASSTHROUGH, |
| 389 | .parent = TYPE_TPM_BACKEND, |
| 390 | .instance_size = sizeof(TPMPassthruState), |
| 391 | .class_init = tpm_passthrough_class_init, |
| 392 | .instance_init = tpm_passthrough_inst_init, |
| 393 | .instance_finalize = tpm_passthrough_inst_finalize, |
| 394 | }; |
| 395 | |
| 396 | static void tpm_passthrough_register(void) |
| 397 | { |
| 398 | type_register_static(&tpm_passthrough_info); |
| 399 | } |
| 400 | |
| 401 | type_init(tpm_passthrough_register) |