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 GPollFD fds[1] = { {.fd = fd, .events = G_IO_IN } }; 116 int n; 117 118 n = write(fd, request, requestlen); 119 if (n < 0) { 120 return -errno; 121 } 122 if (n != requestlen) { 123 return -EFAULT; 124 } 125 126 /* wait for a second */ 127 n = RETRY_ON_EINTR(g_poll(fds, 1, 1000)); 128 if (n != 1) { 129 return -errno; 130 } 131 132 n = read(fd, response, responselen); 133 if (n < sizeof(struct tpm_resp_hdr)) { 134 return -EFAULT; 135 } 136 137 /* check the header */ 138 if (tpm_cmd_get_size(response) != n) { 139 return -EMSGSIZE; 140 } 141 142 return 0; 143 } 144 145 /* 146 * A basic test of a TPM device. We expect a well formatted response header 147 * (error response is fine). 148 */ 149 static int tpm_util_test(int fd, 150 const void *request, 151 size_t requestlen, 152 uint16_t *return_tag) 153 { 154 char buf[1024]; 155 ssize_t ret; 156 157 ret = tpm_util_request(fd, request, requestlen, 158 buf, sizeof(buf)); 159 if (ret < 0) { 160 return ret; 161 } 162 163 *return_tag = tpm_cmd_get_tag(buf); 164 165 return 0; 166 } 167 168 /* 169 * Probe for the TPM device in the back 170 * Returns 0 on success with the version of the probed TPM set, 1 on failure. 171 */ 172 int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version) 173 { 174 /* 175 * Sending a TPM1.2 command to a TPM2 should return a TPM1.2 176 * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e) 177 * 178 * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the 179 * header. 180 * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag 181 * in the header and an error code. 182 */ 183 const struct tpm_req_hdr test_req = { 184 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), 185 .len = cpu_to_be32(sizeof(test_req)), 186 .ordinal = cpu_to_be32(TPM_ORD_GetTicks), 187 }; 188 189 const struct tpm_req_hdr test_req_tpm2 = { 190 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS), 191 .len = cpu_to_be32(sizeof(test_req_tpm2)), 192 .ordinal = cpu_to_be32(TPM2_CC_ReadClock), 193 }; 194 uint16_t return_tag; 195 int ret; 196 197 /* Send TPM 2 command */ 198 ret = tpm_util_test(tpm_fd, &test_req_tpm2, 199 sizeof(test_req_tpm2), &return_tag); 200 /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */ 201 if (!ret && return_tag == TPM2_ST_NO_SESSIONS) { 202 *tpm_version = TPM_VERSION_2_0; 203 return 0; 204 } 205 206 /* Send TPM 1.2 command */ 207 ret = tpm_util_test(tpm_fd, &test_req, 208 sizeof(test_req), &return_tag); 209 if (!ret && return_tag == TPM_TAG_RSP_COMMAND) { 210 *tpm_version = TPM_VERSION_1_2; 211 /* this is a TPM 1.2 */ 212 return 0; 213 } 214 215 *tpm_version = TPM_VERSION_UNSPEC; 216 217 return 1; 218 } 219 220 int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version, 221 size_t *buffersize) 222 { 223 int ret; 224 225 switch (tpm_version) { 226 case TPM_VERSION_1_2: { 227 const struct tpm_req_get_buffer_size { 228 struct tpm_req_hdr hdr; 229 uint32_t capability; 230 uint32_t len; 231 uint32_t subcap; 232 } QEMU_PACKED tpm_get_buffer_size = { 233 .hdr = { 234 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), 235 .len = cpu_to_be32(sizeof(tpm_get_buffer_size)), 236 .ordinal = cpu_to_be32(TPM_ORD_GetCapability), 237 }, 238 .capability = cpu_to_be32(TPM_CAP_PROPERTY), 239 .len = cpu_to_be32(sizeof(uint32_t)), 240 .subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER), 241 }; 242 struct tpm_resp_get_buffer_size { 243 struct tpm_resp_hdr hdr; 244 uint32_t len; 245 uint32_t buffersize; 246 } QEMU_PACKED tpm_resp; 247 248 ret = tpm_util_request(tpm_fd, &tpm_get_buffer_size, 249 sizeof(tpm_get_buffer_size), 250 &tpm_resp, sizeof(tpm_resp)); 251 if (ret < 0) { 252 return ret; 253 } 254 255 if (be32_to_cpu(tpm_resp.hdr.len) != sizeof(tpm_resp) || 256 be32_to_cpu(tpm_resp.len) != sizeof(uint32_t)) { 257 trace_tpm_util_get_buffer_size_hdr_len( 258 be32_to_cpu(tpm_resp.hdr.len), 259 sizeof(tpm_resp)); 260 trace_tpm_util_get_buffer_size_len(be32_to_cpu(tpm_resp.len), 261 sizeof(uint32_t)); 262 error_report("tpm_util: Got unexpected response to " 263 "TPM_GetCapability; errcode: 0x%x", 264 be32_to_cpu(tpm_resp.hdr.errcode)); 265 return -EFAULT; 266 } 267 *buffersize = be32_to_cpu(tpm_resp.buffersize); 268 break; 269 } 270 case TPM_VERSION_2_0: { 271 const struct tpm2_req_get_buffer_size { 272 struct tpm_req_hdr hdr; 273 uint32_t capability; 274 uint32_t property; 275 uint32_t count; 276 } QEMU_PACKED tpm2_get_buffer_size = { 277 .hdr = { 278 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS), 279 .len = cpu_to_be32(sizeof(tpm2_get_buffer_size)), 280 .ordinal = cpu_to_be32(TPM2_CC_GetCapability), 281 }, 282 .capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES), 283 .property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE), 284 .count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */ 285 }; 286 struct tpm2_resp_get_buffer_size { 287 struct tpm_resp_hdr hdr; 288 uint8_t more; 289 uint32_t capability; 290 uint32_t count; 291 uint32_t property1; 292 uint32_t value1; 293 uint32_t property2; 294 uint32_t value2; 295 } QEMU_PACKED tpm2_resp; 296 297 ret = tpm_util_request(tpm_fd, &tpm2_get_buffer_size, 298 sizeof(tpm2_get_buffer_size), 299 &tpm2_resp, sizeof(tpm2_resp)); 300 if (ret < 0) { 301 return ret; 302 } 303 304 if (be32_to_cpu(tpm2_resp.hdr.len) != sizeof(tpm2_resp) || 305 be32_to_cpu(tpm2_resp.count) != 2) { 306 trace_tpm_util_get_buffer_size_hdr_len2( 307 be32_to_cpu(tpm2_resp.hdr.len), 308 sizeof(tpm2_resp)); 309 trace_tpm_util_get_buffer_size_len2( 310 be32_to_cpu(tpm2_resp.count), 2); 311 error_report("tpm_util: Got unexpected response to " 312 "TPM2_GetCapability; errcode: 0x%x", 313 be32_to_cpu(tpm2_resp.hdr.errcode)); 314 return -EFAULT; 315 } 316 *buffersize = MAX(be32_to_cpu(tpm2_resp.value1), 317 be32_to_cpu(tpm2_resp.value2)); 318 break; 319 } 320 case TPM_VERSION_UNSPEC: 321 return -EFAULT; 322 } 323 324 trace_tpm_util_get_buffer_size(*buffersize); 325 326 return 0; 327 } 328 329 void tpm_sized_buffer_reset(TPMSizedBuffer *tsb) 330 { 331 g_free(tsb->buffer); 332 tsb->buffer = NULL; 333 tsb->size = 0; 334 } 335 336 void tpm_util_show_buffer(const unsigned char *buffer, 337 size_t buffer_size, const char *string) 338 { 339 size_t len, i; 340 char *line_buffer, *p; 341 342 if (!trace_event_get_state_backends(TRACE_TPM_UTIL_SHOW_BUFFER_CONTENT)) { 343 return; 344 } 345 len = MIN(tpm_cmd_get_size(buffer), buffer_size); 346 trace_tpm_util_show_buffer_header(string, len); 347 348 /* 349 * allocate enough room for 3 chars per buffer entry plus a 350 * newline after every 16 chars and a final null terminator. 351 */ 352 line_buffer = g_malloc(len * 3 + (len / 16) + 1); 353 354 for (i = 0, p = line_buffer; i < len; i++) { 355 if (i && !(i % 16)) { 356 p += sprintf(p, "\n"); 357 } 358 p += sprintf(p, "%.2X ", buffer[i]); 359 } 360 trace_tpm_util_show_buffer_content(line_buffer); 361 362 g_free(line_buffer); 363 } 364