src/lib/tlcl.c

   1 /* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
   2  * Use of this source code is governed by a BSD-style license that can be
   3  * found in the LICENSE file.
   4  */
   5
   6 /* A lightweight TPM command library.
   7  *
   8  * The general idea is that TPM commands are array of bytes whose
   9  * fields are mostly compile-time constant.  The goal is to build much
  10  * of the commands at compile time (or build time) and change some of
  11  * the fields at run time as needed.  The code in
  12  * utility/tlcl_generator.c builds structures containing the commands,
  13  * as well as the offsets of the fields that need to be set at run
  14  * time.
  15  */
  16
  17 #include <arch/early_variables.h>
  18 #include <assert.h>
  19 #include <string.h>
  20 #include <tpm_lite/tlcl.h>
  21 #include <tpm.h>
  22 #include <vb2_api.h>
  23 #include "tlcl_internal.h"
  24 #include "tlcl_structures.h"
  25
  26 #ifdef FOR_TEST
  27 #include <stdio.h>
  28 #define VBDEBUG(format, args...) printf(format, ## args)
  29 #else
  30 #include <console/console.h>
  31 #define VBDEBUG(format, args...) printk(BIOS_DEBUG, format, ## args)
  32 #endif
  33
  34 static int tpm_send_receive(const uint8_t *request,
  35                                 uint32_t request_length,
  36                                 uint8_t *response,
  37                                 uint32_t *response_length)
  38 {
  39         size_t len = *response_length;
  40         if (tis_sendrecv(request, request_length, response, &len))
  41                 return VB2_ERROR_UNKNOWN;
  42         /* check 64->32bit overflow and (re)check response buffer overflow */
  43         if (len > *response_length)
  44                 return VB2_ERROR_UNKNOWN;
  45         *response_length = len;
  46         return VB2_SUCCESS;
  47 }
  48
  49 /* Sets the size field of a TPM command. */
  50 static inline void set_tpm_command_size(uint8_t *buffer, uint32_t size)
  51 {
  52         to_tpm_uint32(buffer + sizeof(uint16_t), size);
  53 }
  54
  55 /* Gets the size field of a TPM command. */
  56 __attribute__((unused))
  57 static inline int tpm_command_size(const uint8_t *buffer)
  58 {
  59         uint32_t size;
  60         from_tpm_uint32(buffer + sizeof(uint16_t), &size);
  61         return (int) size;
  62 }
  63
  64 /* Gets the code field of a TPM command. */
  65 static inline int tpm_command_code(const uint8_t *buffer)
  66 {
  67         uint32_t code;
  68         from_tpm_uint32(buffer + sizeof(uint16_t) + sizeof(uint32_t), &code);
  69         return code;
  70 }
  71
  72 /* Gets the return code field of a TPM result. */
  73 static inline int tpm_return_code(const uint8_t *buffer)
  74 {
  75         return tpm_command_code(buffer);
  76 }
  77
  78 /* Like TlclSendReceive below, but do not retry if NEEDS_SELFTEST or
  79  * DOING_SELFTEST errors are returned.
  80  */
  81 static uint32_t tlcl_send_receive_no_retry(const uint8_t *request,
  82                                            uint8_t *response, int max_length)
  83 {
  84         uint32_t response_length = max_length;
  85         uint32_t result;
  86
  87         result = tpm_send_receive(request, tpm_command_size(request),
  88                                         response, &response_length);
  89         if (result != 0) {
  90                 /* Communication with TPM failed, so response is garbage */
  91                 VBDEBUG("TPM: command 0x%x send/receive failed: 0x%x\n",
  92                         tpm_command_code(request), result);
  93                 return result;
  94         }
  95         /* Otherwise, use the result code from the response */
  96         result = tpm_return_code(response);
  97
  98         /* TODO: add paranoia about returned response_length vs. max_length
  99          * (and possibly expected length from the response header).  See
 100          * crosbug.com/17017 */
 101
 102         VBDEBUG("TPM: command 0x%x returned 0x%x\n",
 103                 tpm_command_code(request), result);
 104
 105 return result;
 106 }
 107
 108
 109 /* Sends a TPM command and gets a response.  Returns 0 if success or the TPM
 110  * error code if error. Waits for the self test to complete if needed. */
 111 uint32_t tlcl_send_receive(const uint8_t *request, uint8_t *response,
 112                            int max_length)
 113 {
 114         uint32_t result = tlcl_send_receive_no_retry(request, response,
 115                                                      max_length);
 116         /* If the command fails because the self test has not completed, try it
 117          * again after attempting to ensure that the self test has completed. */
 118         if (result == TPM_E_NEEDS_SELFTEST || result == TPM_E_DOING_SELFTEST) {
 119                 result = tlcl_continue_self_test();
 120                 if (result != TPM_SUCCESS)
 121                         return result;
 122 #if defined(TPM_BLOCKING_CONTINUESELFTEST) || defined(VB_RECOVERY_MODE)
 123                 /* Retry only once */
 124                 result = tlcl_send_receive_no_retry(request, response,
 125                                                     max_length);
 126 #else
 127                 /* This needs serious testing. The TPM specification says: "iii.
 128                  * The caller MUST wait for the actions of TPM_ContinueSelfTest
 129                  * to complete before reissuing the command C1."  But, if
 130                  * ContinueSelfTest is non-blocking, how do we know that the
 131                  * actions have completed other than trying again? */
 132                 do {
 133                         result = tlcl_send_receive_no_retry(request, response,
 134                                                             max_length);
 135                 } while (result == TPM_E_DOING_SELFTEST);
 136 #endif
 137         }
 138         return result;
 139 }
 140
 141 /* Sends a command and returns the error code. */
 142 static uint32_t send(const uint8_t *command)
 143 {
 144         uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 145         return tlcl_send_receive(command, response, sizeof(response));
 146 }
 147
 148 /* Exported functions. */
 149
 150 static uint8_t tlcl_init_done CAR_GLOBAL;
 151
 152 uint32_t tlcl_lib_init(void)
 153 {
 154         uint8_t done = car_get_var(tlcl_init_done);
 155         if (done)
 156                 return VB2_SUCCESS;
 157
 158         if (tis_init())
 159                 return VB2_ERROR_UNKNOWN;
 160         if (tis_open())
 161                 return VB2_ERROR_UNKNOWN;
 162
 163         car_set_var(tlcl_init_done, 1);
 164
 165         return VB2_SUCCESS;
 166 }
 167
 168 uint32_t tlcl_startup(void)
 169 {
 170         VBDEBUG("TPM: Startup\n");
 171         return send(tpm_startup_cmd.buffer);
 172 }
 173
 174 uint32_t tlcl_resume(void)
 175 {
 176         VBDEBUG("TPM: Resume\n");
 177         return send(tpm_resume_cmd.buffer);
 178 }
 179
 180 uint32_t tlcl_self_test_full(void)
 181 {
 182         VBDEBUG("TPM: Self test full\n");
 183         return send(tpm_selftestfull_cmd.buffer);
 184 }
 185
 186 uint32_t tlcl_continue_self_test(void)
 187 {
 188         uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 189         VBDEBUG("TPM: Continue self test\n");
 190         /* Call the No Retry version of SendReceive to avoid recursion. */
 191         return tlcl_send_receive_no_retry(tpm_continueselftest_cmd.buffer,
 192                                           response, sizeof(response));
 193 }
 194
 195 uint32_t tlcl_define_space(uint32_t index, uint32_t perm, uint32_t size)
 196 {
 197         struct s_tpm_nv_definespace_cmd cmd;
 198         VBDEBUG("TPM: TlclDefineSpace(0x%x, 0x%x, %d)\n", index, perm, size);
 199         memcpy(&cmd, &tpm_nv_definespace_cmd, sizeof(cmd));
 200         to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.index, index);
 201         to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.perm, perm);
 202         to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.size, size);
 203         return send(cmd.buffer);
 204 }
 205
 206 uint32_t tlcl_write(uint32_t index, const void *data, uint32_t length)
 207 {
 208         struct s_tpm_nv_write_cmd cmd;
 209         uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 210         const int total_length =
 211                         kTpmRequestHeaderLength + kWriteInfoLength + length;
 212
 213         VBDEBUG("TPM: tlcl_write(0x%x, %d)\n", index, length);
 214         memcpy(&cmd, &tpm_nv_write_cmd, sizeof(cmd));
 215         assert(total_length <= TPM_LARGE_ENOUGH_COMMAND_SIZE);
 216         set_tpm_command_size(cmd.buffer, total_length);
 217
 218         to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.index, index);
 219         to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.length, length);
 220         memcpy(cmd.buffer + tpm_nv_write_cmd.data, data, length);
 221
 222         return tlcl_send_receive(cmd.buffer, response, sizeof(response));
 223 }
 224
 225 uint32_t tlcl_read(uint32_t index, void *data, uint32_t length)
 226 {
 227         struct s_tpm_nv_read_cmd cmd;
 228         uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 229         uint32_t result_length;
 230         uint32_t result;
 231
 232         VBDEBUG("TPM: tlcl_read(0x%x, %d)\n", index, length);
 233         memcpy(&cmd, &tpm_nv_read_cmd, sizeof(cmd));
 234         to_tpm_uint32(cmd.buffer + tpm_nv_read_cmd.index, index);
 235         to_tpm_uint32(cmd.buffer + tpm_nv_read_cmd.length, length);
 236
 237         result = tlcl_send_receive(cmd.buffer, response, sizeof(response));
 238         if (result == TPM_SUCCESS && length > 0) {
 239                 uint8_t *nv_read_cursor = response + kTpmResponseHeaderLength;
 240                 from_tpm_uint32(nv_read_cursor, &result_length);
 241                 nv_read_cursor += sizeof(uint32_t);
 242                 memcpy(data, nv_read_cursor, result_length);
 243         }
 244
 245         return result;
 246 }
 247
 248
 249 uint32_t tlcl_assert_physical_presence(void)
 250 {
 251         VBDEBUG("TPM: Asserting physical presence\n");
 252         return send(tpm_ppassert_cmd.buffer);
 253 }
 254
 255 uint32_t tlcl_physical_presence_cmd_enable(void)
 256 {
 257         VBDEBUG("TPM: Enable the physical presence command\n");
 258         return send(tpm_ppenable_cmd.buffer);
 259 }
 260
 261 uint32_t tlcl_finalize_physical_presence(void)
 262 {
 263         VBDEBUG("TPM: Enable PP cmd, disable HW pp, and set lifetime lock\n");
 264         return send(tpm_finalizepp_cmd.buffer);
 265 }
 266
 267 uint32_t tlcl_set_nv_locked(void)
 268 {
 269         VBDEBUG("TPM: Set NV locked\n");
 270         return tlcl_define_space(TPM_NV_INDEX_LOCK, 0, 0);
 271 }
 272
 273 uint32_t tlcl_force_clear(void)
 274 {
 275         VBDEBUG("TPM: Force clear\n");
 276         return send(tpm_forceclear_cmd.buffer);
 277 }
 278
 279 uint32_t tlcl_set_enable(void)
 280 {
 281         VBDEBUG("TPM: Enabling TPM\n");
 282         return send(tpm_physicalenable_cmd.buffer);
 283 }
 284
 285 uint32_t tlcl_set_deactivated(uint8_t flag)
 286 {
 287         struct s_tpm_physicalsetdeactivated_cmd cmd;
 288         VBDEBUG("TPM: SetDeactivated(%d)\n", flag);
 289         memcpy(&cmd, &tpm_physicalsetdeactivated_cmd, sizeof(cmd));
 290         *(cmd.buffer + cmd.deactivated) = flag;
 291         return send(cmd.buffer);
 292 }
 293
 294 uint32_t tlcl_get_permanent_flags(TPM_PERMANENT_FLAGS *pflags)
 295 {
 296         uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
 297         uint32_t size;
 298         uint32_t result = tlcl_send_receive(tpm_getflags_cmd.buffer, response,
 299                                             sizeof(response));
 300         if (result != TPM_SUCCESS)
 301                 return result;
 302         from_tpm_uint32(response + kTpmResponseHeaderLength, &size);
 303         assert(size == sizeof(TPM_PERMANENT_FLAGS));
 304         memcpy(pflags, response + kTpmResponseHeaderLength + sizeof(size),
 305                sizeof(TPM_PERMANENT_FLAGS));
 306         return result;
 307 }
 308
 309 uint32_t tlcl_get_flags(uint8_t *disable, uint8_t *deactivated,
 310                         uint8_t *nvlocked)
 311 {
 312         TPM_PERMANENT_FLAGS pflags;
 313         uint32_t result = tlcl_get_permanent_flags(&pflags);
 314         if (result == TPM_SUCCESS) {
 315                 if (disable)
 316                         *disable = pflags.disable;
 317                 if (deactivated)
 318                         *deactivated = pflags.deactivated;
 319                 if (nvlocked)
 320                         *nvlocked = pflags.nvLocked;
 321                 VBDEBUG("TPM: flags disable=%d, deactivated=%d, nvlocked=%d\n",
 322                         pflags.disable, pflags.deactivated, pflags.nvLocked);
 323         }
 324         return result;
 325 }
 326
 327 uint32_t tlcl_set_global_lock(void)
 328 {
 329         uint32_t x;
 330         VBDEBUG("TPM: Set global lock\n");
 331         return tlcl_write(TPM_NV_INDEX0, (uint8_t *) &x, 0);
 332 }
 333
 334 uint32_t tlcl_extend(int pcr_num, const uint8_t *in_digest,
 335                      uint8_t *out_digest)
 336 {
 337         struct s_tpm_extend_cmd cmd;
 338         uint8_t response[kTpmResponseHeaderLength + kPcrDigestLength];
 339         uint32_t result;
 340
 341         memcpy(&cmd, &tpm_extend_cmd, sizeof(cmd));
 342         to_tpm_uint32(cmd.buffer + tpm_extend_cmd.pcrNum, pcr_num);
 343         memcpy(cmd.buffer + cmd.inDigest, in_digest, kPcrDigestLength);
 344
 345         result = tlcl_send_receive(cmd.buffer, response, sizeof(response));
 346         if (result != TPM_SUCCESS)
 347                 return result;
 348
 349         if (out_digest)
 350                 memcpy(out_digest, response + kTpmResponseHeaderLength,
 351                        kPcrDigestLength);
 352         return result;
 353 }