tpm_util.c (10979B)
1 /* 2 * TPM utility functions 3 * 4 * Copyright (c) 2010 - 2015 IBM Corporation 5 * Authors: 6 * Stefan Berger <stefanb@us.ibm.com> 7 * 8 * This library is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * This library is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with this library; if not, see <http://www.gnu.org/licenses/> 20 */ 21 22 #include "qemu/osdep.h" 23 #include "qemu/error-report.h" 24 #include "qapi/error.h" 25 #include "qapi/visitor.h" 26 #include "tpm_int.h" 27 #include "exec/memory.h" 28 #include "hw/qdev-properties.h" 29 #include "sysemu/tpm_backend.h" 30 #include "sysemu/tpm_util.h" 31 #include "trace.h" 32 33 /* tpm backend property */ 34 35 static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque, 36 Error **errp) 37 { 38 TPMBackend **be = object_field_prop_ptr(obj, opaque); 39 char *p; 40 41 p = g_strdup(*be ? (*be)->id : ""); 42 visit_type_str(v, name, &p, errp); 43 g_free(p); 44 } 45 46 static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque, 47 Error **errp) 48 { 49 Property *prop = opaque; 50 TPMBackend *s, **be = object_field_prop_ptr(obj, prop); 51 char *str; 52 53 if (!visit_type_str(v, name, &str, errp)) { 54 return; 55 } 56 57 s = qemu_find_tpm_be(str); 58 if (s == NULL) { 59 error_setg(errp, "Property '%s.%s' can't find value '%s'", 60 object_get_typename(obj), name, str); 61 } else if (tpm_backend_init(s, TPM_IF(obj), errp) == 0) { 62 *be = s; /* weak reference, avoid cyclic ref */ 63 } 64 g_free(str); 65 } 66 67 static void release_tpm(Object *obj, const char *name, void *opaque) 68 { 69 Property *prop = opaque; 70 TPMBackend **be = object_field_prop_ptr(obj, prop); 71 72 if (*be) { 73 tpm_backend_reset(*be); 74 } 75 } 76 77 const PropertyInfo qdev_prop_tpm = { 78 .name = "str", 79 .description = "ID of a tpm to use as a backend", 80 .get = get_tpm, 81 .set = set_tpm, 82 .release = release_tpm, 83 }; 84 85 /* 86 * Write an error message in the given output buffer. 87 */ 88 void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len) 89 { 90 if (out_len >= sizeof(struct tpm_resp_hdr)) { 91 tpm_cmd_set_tag(out, TPM_TAG_RSP_COMMAND); 92 tpm_cmd_set_size(out, sizeof(struct tpm_resp_hdr)); 93 tpm_cmd_set_error(out, TPM_FAIL); 94 } 95 } 96 97 bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len) 98 { 99 if (in_len >= sizeof(struct tpm_req_hdr)) { 100 return tpm_cmd_get_ordinal(in) == TPM_ORD_ContinueSelfTest; 101 } 102 103 return false; 104 } 105 106 /* 107 * Send request to a TPM device. We expect a response within one second. 108 */ 109 static int tpm_util_request(int fd, 110 const void *request, 111 size_t requestlen, 112 void *response, 113 size_t responselen) 114 { 115 fd_set readfds; 116 int n; 117 struct timeval tv = { 118 .tv_sec = 1, 119 .tv_usec = 0, 120 }; 121 122 n = write(fd, request, requestlen); 123 if (n < 0) { 124 return -errno; 125 } 126 if (n != requestlen) { 127 return -EFAULT; 128 } 129 130 FD_ZERO(&readfds); 131 FD_SET(fd, &readfds); 132 133 /* wait for a second */ 134 n = select(fd + 1, &readfds, NULL, NULL, &tv); 135 if (n != 1) { 136 return -errno; 137 } 138 139 n = read(fd, response, responselen); 140 if (n < sizeof(struct tpm_resp_hdr)) { 141 return -EFAULT; 142 } 143 144 /* check the header */ 145 if (tpm_cmd_get_size(response) != n) { 146 return -EMSGSIZE; 147 } 148 149 return 0; 150 } 151 152 /* 153 * A basic test of a TPM device. We expect a well formatted response header 154 * (error response is fine). 155 */ 156 static int tpm_util_test(int fd, 157 const void *request, 158 size_t requestlen, 159 uint16_t *return_tag) 160 { 161 char buf[1024]; 162 ssize_t ret; 163 164 ret = tpm_util_request(fd, request, requestlen, 165 buf, sizeof(buf)); 166 if (ret < 0) { 167 return ret; 168 } 169 170 *return_tag = tpm_cmd_get_tag(buf); 171 172 return 0; 173 } 174 175 /* 176 * Probe for the TPM device in the back 177 * Returns 0 on success with the version of the probed TPM set, 1 on failure. 178 */ 179 int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version) 180 { 181 /* 182 * Sending a TPM1.2 command to a TPM2 should return a TPM1.2 183 * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e) 184 * 185 * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the 186 * header. 187 * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag 188 * in the header and an error code. 189 */ 190 const struct tpm_req_hdr test_req = { 191 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), 192 .len = cpu_to_be32(sizeof(test_req)), 193 .ordinal = cpu_to_be32(TPM_ORD_GetTicks), 194 }; 195 196 const struct tpm_req_hdr test_req_tpm2 = { 197 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS), 198 .len = cpu_to_be32(sizeof(test_req_tpm2)), 199 .ordinal = cpu_to_be32(TPM2_CC_ReadClock), 200 }; 201 uint16_t return_tag; 202 int ret; 203 204 /* Send TPM 2 command */ 205 ret = tpm_util_test(tpm_fd, &test_req_tpm2, 206 sizeof(test_req_tpm2), &return_tag); 207 /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */ 208 if (!ret && return_tag == TPM2_ST_NO_SESSIONS) { 209 *tpm_version = TPM_VERSION_2_0; 210 return 0; 211 } 212 213 /* Send TPM 1.2 command */ 214 ret = tpm_util_test(tpm_fd, &test_req, 215 sizeof(test_req), &return_tag); 216 if (!ret && return_tag == TPM_TAG_RSP_COMMAND) { 217 *tpm_version = TPM_VERSION_1_2; 218 /* this is a TPM 1.2 */ 219 return 0; 220 } 221 222 *tpm_version = TPM_VERSION_UNSPEC; 223 224 return 1; 225 } 226 227 int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version, 228 size_t *buffersize) 229 { 230 int ret; 231 232 switch (tpm_version) { 233 case TPM_VERSION_1_2: { 234 const struct tpm_req_get_buffer_size { 235 struct tpm_req_hdr hdr; 236 uint32_t capability; 237 uint32_t len; 238 uint32_t subcap; 239 } QEMU_PACKED tpm_get_buffer_size = { 240 .hdr = { 241 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), 242 .len = cpu_to_be32(sizeof(tpm_get_buffer_size)), 243 .ordinal = cpu_to_be32(TPM_ORD_GetCapability), 244 }, 245 .capability = cpu_to_be32(TPM_CAP_PROPERTY), 246 .len = cpu_to_be32(sizeof(uint32_t)), 247 .subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER), 248 }; 249 struct tpm_resp_get_buffer_size { 250 struct tpm_resp_hdr hdr; 251 uint32_t len; 252 uint32_t buffersize; 253 } QEMU_PACKED tpm_resp; 254 255 ret = tpm_util_request(tpm_fd, &tpm_get_buffer_size, 256 sizeof(tpm_get_buffer_size), 257 &tpm_resp, sizeof(tpm_resp)); 258 if (ret < 0) { 259 return ret; 260 } 261 262 if (be32_to_cpu(tpm_resp.hdr.len) != sizeof(tpm_resp) || 263 be32_to_cpu(tpm_resp.len) != sizeof(uint32_t)) { 264 trace_tpm_util_get_buffer_size_hdr_len( 265 be32_to_cpu(tpm_resp.hdr.len), 266 sizeof(tpm_resp)); 267 trace_tpm_util_get_buffer_size_len(be32_to_cpu(tpm_resp.len), 268 sizeof(uint32_t)); 269 error_report("tpm_util: Got unexpected response to " 270 "TPM_GetCapability; errcode: 0x%x", 271 be32_to_cpu(tpm_resp.hdr.errcode)); 272 return -EFAULT; 273 } 274 *buffersize = be32_to_cpu(tpm_resp.buffersize); 275 break; 276 } 277 case TPM_VERSION_2_0: { 278 const struct tpm2_req_get_buffer_size { 279 struct tpm_req_hdr hdr; 280 uint32_t capability; 281 uint32_t property; 282 uint32_t count; 283 } QEMU_PACKED tpm2_get_buffer_size = { 284 .hdr = { 285 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS), 286 .len = cpu_to_be32(sizeof(tpm2_get_buffer_size)), 287 .ordinal = cpu_to_be32(TPM2_CC_GetCapability), 288 }, 289 .capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES), 290 .property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE), 291 .count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */ 292 }; 293 struct tpm2_resp_get_buffer_size { 294 struct tpm_resp_hdr hdr; 295 uint8_t more; 296 uint32_t capability; 297 uint32_t count; 298 uint32_t property1; 299 uint32_t value1; 300 uint32_t property2; 301 uint32_t value2; 302 } QEMU_PACKED tpm2_resp; 303 304 ret = tpm_util_request(tpm_fd, &tpm2_get_buffer_size, 305 sizeof(tpm2_get_buffer_size), 306 &tpm2_resp, sizeof(tpm2_resp)); 307 if (ret < 0) { 308 return ret; 309 } 310 311 if (be32_to_cpu(tpm2_resp.hdr.len) != sizeof(tpm2_resp) || 312 be32_to_cpu(tpm2_resp.count) != 2) { 313 trace_tpm_util_get_buffer_size_hdr_len2( 314 be32_to_cpu(tpm2_resp.hdr.len), 315 sizeof(tpm2_resp)); 316 trace_tpm_util_get_buffer_size_len2( 317 be32_to_cpu(tpm2_resp.count), 2); 318 error_report("tpm_util: Got unexpected response to " 319 "TPM2_GetCapability; errcode: 0x%x", 320 be32_to_cpu(tpm2_resp.hdr.errcode)); 321 return -EFAULT; 322 } 323 *buffersize = MAX(be32_to_cpu(tpm2_resp.value1), 324 be32_to_cpu(tpm2_resp.value2)); 325 break; 326 } 327 case TPM_VERSION_UNSPEC: 328 return -EFAULT; 329 } 330 331 trace_tpm_util_get_buffer_size(*buffersize); 332 333 return 0; 334 } 335 336 void tpm_sized_buffer_reset(TPMSizedBuffer *tsb) 337 { 338 g_free(tsb->buffer); 339 tsb->buffer = NULL; 340 tsb->size = 0; 341 } 342 343 void tpm_util_show_buffer(const unsigned char *buffer, 344 size_t buffer_size, const char *string) 345 { 346 size_t len, i; 347 char *line_buffer, *p; 348 349 if (!trace_event_get_state_backends(TRACE_TPM_UTIL_SHOW_BUFFER)) { 350 return; 351 } 352 len = MIN(tpm_cmd_get_size(buffer), buffer_size); 353 354 /* 355 * allocate enough room for 3 chars per buffer entry plus a 356 * newline after every 16 chars and a final null terminator. 357 */ 358 line_buffer = g_malloc(len * 3 + (len / 16) + 1); 359 360 for (i = 0, p = line_buffer; i < len; i++) { 361 if (i && !(i % 16)) { 362 p += sprintf(p, "\n"); 363 } 364 p += sprintf(p, "%.2X ", buffer[i]); 365 } 366 trace_tpm_util_show_buffer(string, len, line_buffer); 367 368 g_free(line_buffer); 369 }