lib/efi_loader/efi_variable.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * UEFI runtime variable services
   4  *
   5  * Copyright (c) 2017 Rob Clark
   6  */
   7
   8 #include <common.h>
   9 #include <efi_loader.h>
  10 #include <env_internal.h>
  11 #include <hexdump.h>
  12 #include <malloc.h>
  13 #include <rtc.h>
  14 #include <search.h>
  15 #include <crypto/pkcs7_parser.h>
  16 #include <linux/compat.h>
  17 #include <u-boot/crc.h>
  18
  19 enum efi_secure_mode {
  20         EFI_MODE_SETUP,
  21         EFI_MODE_USER,
  22         EFI_MODE_AUDIT,
  23         EFI_MODE_DEPLOYED,
  24 };
  25
  26 const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
  27 static bool efi_secure_boot;
  28 static int efi_secure_mode;
  29 static u8 efi_vendor_keys;
  30
  31 #define READ_ONLY BIT(31)
  32
  33 /*
  34  * Mapping between EFI variables and u-boot variables:
  35  *
  36  *   efi_$guid_$varname = {attributes}(type)value
  37  *
  38  * For example:
  39  *
  40  *   efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported=
  41  *      "{ro,boot,run}(blob)0000000000000000"
  42  *   efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder=
  43  *      "(blob)00010000"
  44  *
  45  * The attributes are a comma separated list of these possible
  46  * attributes:
  47  *
  48  *   + ro   - read-only
  49  *   + boot - boot-services access
  50  *   + run  - runtime access
  51  *
  52  * NOTE: with current implementation, no variables are available after
  53  * ExitBootServices, and all are persisted (if possible).
  54  *
  55  * If not specified, the attributes default to "{boot}".
  56  *
  57  * The required type is one of:
  58  *
  59  *   + utf8 - raw utf8 string
  60  *   + blob - arbitrary length hex string
  61  *
  62  * Maybe a utf16 type would be useful to for a string value to be auto
  63  * converted to utf16?
  64  */
  65
  66 #define PREFIX_LEN (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx_"))
  67
  68 /**
  69  * efi_to_native() - convert the UEFI variable name and vendor GUID to U-Boot
  70  *                   variable name
  71  *
  72  * The U-Boot variable name is a concatenation of prefix 'efi', the hexstring
  73  * encoded vendor GUID, and the UTF-8 encoded UEFI variable name separated by
  74  * underscores, e.g. 'efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder'.
  75  *
  76  * @native:             pointer to pointer to U-Boot variable name
  77  * @variable_name:      UEFI variable name
  78  * @vendor:             vendor GUID
  79  * Return:              status code
  80  */
  81 static efi_status_t efi_to_native(char **native, const u16 *variable_name,
  82                                   const efi_guid_t *vendor)
  83 {
  84         size_t len;
  85         char *pos;
  86
  87         len = PREFIX_LEN + utf16_utf8_strlen(variable_name) + 1;
  88         *native = malloc(len);
  89         if (!*native)
  90                 return EFI_OUT_OF_RESOURCES;
  91
  92         pos = *native;
  93         pos += sprintf(pos, "efi_%pUl_", vendor);
  94         utf16_utf8_strcpy(&pos, variable_name);
  95
  96         return EFI_SUCCESS;
  97 }
  98
  99 /**
 100  * prefix() - skip over prefix
 101  *
 102  * Skip over a prefix string.
 103  *
 104  * @str:        string with prefix
 105  * @prefix:     prefix string
 106  * Return:      string without prefix, or NULL if prefix not found
 107  */
 108 static const char *prefix(const char *str, const char *prefix)
 109 {
 110         size_t n = strlen(prefix);
 111         if (!strncmp(prefix, str, n))
 112                 return str + n;
 113         return NULL;
 114 }
 115
 116 /**
 117  * parse_attr() - decode attributes part of variable value
 118  *
 119  * Convert the string encoded attributes of a UEFI variable to a bit mask.
 120  * TODO: Several attributes are not supported.
 121  *
 122  * @str:        value of U-Boot variable
 123  * @attrp:      pointer to UEFI attributes
 124  * @timep:      pointer to time attribute
 125  * Return:      pointer to remainder of U-Boot variable value
 126  */
 127 static const char *parse_attr(const char *str, u32 *attrp, u64 *timep)
 128 {
 129         u32 attr = 0;
 130         char sep = '{';
 131
 132         if (*str != '{') {
 133                 *attrp = EFI_VARIABLE_BOOTSERVICE_ACCESS;
 134                 return str;
 135         }
 136
 137         while (*str == sep) {
 138                 const char *s;
 139
 140                 str++;
 141
 142                 if ((s = prefix(str, "ro"))) {
 143                         attr |= READ_ONLY;
 144                 } else if ((s = prefix(str, "nv"))) {
 145                         attr |= EFI_VARIABLE_NON_VOLATILE;
 146                 } else if ((s = prefix(str, "boot"))) {
 147                         attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
 148                 } else if ((s = prefix(str, "run"))) {
 149                         attr |= EFI_VARIABLE_RUNTIME_ACCESS;
 150                 } else if ((s = prefix(str, "time="))) {
 151                         attr |= EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
 152                         hex2bin((u8 *)timep, s, sizeof(*timep));
 153                         s += sizeof(*timep) * 2;
 154                 } else if (*str == '}') {
 155                         break;
 156                 } else {
 157                         printf("invalid attribute: %s\n", str);
 158                         break;
 159                 }
 160
 161                 str = s;
 162                 sep = ',';
 163         }
 164
 165         str++;
 166
 167         *attrp = attr;
 168
 169         return str;
 170 }
 171
 172 static efi_status_t efi_set_variable_internal(u16 *variable_name,
 173                                               const efi_guid_t *vendor,
 174                                               u32 attributes,
 175                                               efi_uintn_t data_size,
 176                                               const void *data,
 177                                               bool ro_check);
 178
 179 /**
 180  * efi_set_secure_state - modify secure boot state variables
 181  * @sec_boot:           value of SecureBoot
 182  * @setup_mode:         value of SetupMode
 183  * @audit_mode:         value of AuditMode
 184  * @deployed_mode:      value of DeployedMode
 185  *
 186  * Modify secure boot stat-related variables as indicated.
 187  *
 188  * Return:              status code
 189  */
 190 static efi_status_t efi_set_secure_state(int sec_boot, int setup_mode,
 191                                          int audit_mode, int deployed_mode)
 192 {
 193         u32 attributes;
 194         efi_status_t ret;
 195
 196         attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
 197                      EFI_VARIABLE_RUNTIME_ACCESS |
 198                      READ_ONLY;
 199         ret = efi_set_variable_internal(L"SecureBoot",
 200                                         &efi_global_variable_guid,
 201                                         attributes,
 202                                         sizeof(sec_boot), &sec_boot,
 203                                         false);
 204         if (ret != EFI_SUCCESS)
 205                 goto err;
 206
 207         ret = efi_set_variable_internal(L"SetupMode",
 208                                         &efi_global_variable_guid,
 209                                         attributes,
 210                                         sizeof(setup_mode), &setup_mode,
 211                                         false);
 212         if (ret != EFI_SUCCESS)
 213                 goto err;
 214
 215         ret = efi_set_variable_internal(L"AuditMode",
 216                                         &efi_global_variable_guid,
 217                                         attributes,
 218                                         sizeof(audit_mode), &audit_mode,
 219                                         false);
 220         if (ret != EFI_SUCCESS)
 221                 goto err;
 222
 223         ret = efi_set_variable_internal(L"DeployedMode",
 224                                         &efi_global_variable_guid,
 225                                         attributes,
 226                                         sizeof(deployed_mode), &deployed_mode,
 227                                         false);
 228 err:
 229         return ret;
 230 }
 231
 232 /**
 233  * efi_transfer_secure_state - handle a secure boot state transition
 234  * @mode:       new state
 235  *
 236  * Depending on @mode, secure boot related variables are updated.
 237  * Those variables are *read-only* for users, efi_set_variable_internal()
 238  * is called here.
 239  *
 240  * Return:      EFI_SUCCESS on success, status code (negative) on error
 241  */
 242 static efi_status_t efi_transfer_secure_state(enum efi_secure_mode mode)
 243 {
 244         efi_status_t ret;
 245
 246         debug("Switching secure state from %d to %d\n", efi_secure_mode, mode);
 247
 248         if (mode == EFI_MODE_DEPLOYED) {
 249                 ret = efi_set_secure_state(1, 0, 0, 1);
 250                 if (ret != EFI_SUCCESS)
 251                         goto err;
 252
 253                 efi_secure_boot = true;
 254         } else if (mode == EFI_MODE_AUDIT) {
 255                 ret = efi_set_variable_internal(
 256                                         L"PK", &efi_global_variable_guid,
 257                                         EFI_VARIABLE_BOOTSERVICE_ACCESS |
 258                                         EFI_VARIABLE_RUNTIME_ACCESS,
 259                                         0, NULL, false);
 260                 if (ret != EFI_SUCCESS)
 261                         goto err;
 262
 263                 ret = efi_set_secure_state(0, 1, 1, 0);
 264                 if (ret != EFI_SUCCESS)
 265                         goto err;
 266
 267                 efi_secure_boot = true;
 268         } else if (mode == EFI_MODE_USER) {
 269                 ret = efi_set_secure_state(1, 0, 0, 0);
 270                 if (ret != EFI_SUCCESS)
 271                         goto err;
 272
 273                 efi_secure_boot = true;
 274         } else if (mode == EFI_MODE_SETUP) {
 275                 ret = efi_set_secure_state(0, 1, 0, 0);
 276                 if (ret != EFI_SUCCESS)
 277                         goto err;
 278         } else {
 279                 return EFI_INVALID_PARAMETER;
 280         }
 281
 282         efi_secure_mode = mode;
 283
 284         return EFI_SUCCESS;
 285
 286 err:
 287         /* TODO: What action should be taken here? */
 288         printf("ERROR: Secure state transition failed\n");
 289         return ret;
 290 }
 291
 292 /**
 293  * efi_init_secure_state - initialize secure boot state
 294  *
 295  * Return:      EFI_SUCCESS on success, status code (negative) on error
 296  */
 297 static efi_status_t efi_init_secure_state(void)
 298 {
 299         enum efi_secure_mode mode;
 300         efi_uintn_t size;
 301         efi_status_t ret;
 302
 303         /*
 304          * TODO:
 305          * Since there is currently no "platform-specific" installation
 306          * method of Platform Key, we can't say if VendorKeys is 0 or 1
 307          * precisely.
 308          */
 309
 310         size = 0;
 311         ret = EFI_CALL(efi_get_variable(L"PK", &efi_global_variable_guid,
 312                                         NULL, &size, NULL));
 313         if (ret == EFI_BUFFER_TOO_SMALL) {
 314                 if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT))
 315                         mode = EFI_MODE_USER;
 316                 else
 317                         mode = EFI_MODE_SETUP;
 318
 319                 efi_vendor_keys = 0;
 320         } else if (ret == EFI_NOT_FOUND) {
 321                 mode = EFI_MODE_SETUP;
 322                 efi_vendor_keys = 1;
 323         } else {
 324                 goto err;
 325         }
 326
 327         ret = efi_transfer_secure_state(mode);
 328         if (ret == EFI_SUCCESS)
 329                 ret = efi_set_variable_internal(L"VendorKeys",
 330                                                 &efi_global_variable_guid,
 331                                                 EFI_VARIABLE_BOOTSERVICE_ACCESS
 332                                                  | EFI_VARIABLE_RUNTIME_ACCESS
 333                                                  | READ_ONLY,
 334                                                 sizeof(efi_vendor_keys),
 335                                                 &efi_vendor_keys,
 336                                                 false);
 337
 338 err:
 339         return ret;
 340 }
 341
 342 /**
 343  * efi_secure_boot_enabled - return if secure boot is enabled or not
 344  *
 345  * Return:      true if enabled, false if disabled
 346  */
 347 bool efi_secure_boot_enabled(void)
 348 {
 349         return efi_secure_boot;
 350 }
 351
 352 #ifdef CONFIG_EFI_SECURE_BOOT
 353 static u8 pkcs7_hdr[] = {
 354         /* SEQUENCE */
 355         0x30, 0x82, 0x05, 0xc7,
 356         /* OID: pkcs7-signedData */
 357         0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02,
 358         /* Context Structured? */
 359         0xa0, 0x82, 0x05, 0xb8,
 360 };
 361
 362 /**
 363  * efi_variable_parse_signature - parse a signature in variable
 364  * @buf:        Pointer to variable's value
 365  * @buflen:     Length of @buf
 366  *
 367  * Parse a signature embedded in variable's value and instantiate
 368  * a pkcs7_message structure. Since pkcs7_parse_message() accepts only
 369  * pkcs7's signedData, some header needed be prepended for correctly
 370  * parsing authentication data, particularly for variable's.
 371  *
 372  * Return:      Pointer to pkcs7_message structure on success, NULL on error
 373  */
 374 static struct pkcs7_message *efi_variable_parse_signature(const void *buf,
 375                                                           size_t buflen)
 376 {
 377         u8 *ebuf;
 378         size_t ebuflen, len;
 379         struct pkcs7_message *msg;
 380
 381         /*
 382          * This is the best assumption to check if the binary is
 383          * already in a form of pkcs7's signedData.
 384          */
 385         if (buflen > sizeof(pkcs7_hdr) &&
 386             !memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) {
 387                 msg = pkcs7_parse_message(buf, buflen);
 388                 goto out;
 389         }
 390
 391         /*
 392          * Otherwise, we should add a dummy prefix sequence for pkcs7
 393          * message parser to be able to process.
 394          * NOTE: EDK2 also uses similar hack in WrapPkcs7Data()
 395          * in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c
 396          * TODO:
 397          * The header should be composed in a more refined manner.
 398          */
 399         debug("Makeshift prefix added to authentication data\n");
 400         ebuflen = sizeof(pkcs7_hdr) + buflen;
 401         if (ebuflen <= 0x7f) {
 402                 debug("Data is too short\n");
 403                 return NULL;
 404         }
 405
 406         ebuf = malloc(ebuflen);
 407         if (!ebuf) {
 408                 debug("Out of memory\n");
 409                 return NULL;
 410         }
 411
 412         memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr));
 413         memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen);
 414         len = ebuflen - 4;
 415         ebuf[2] = (len >> 8) & 0xff;
 416         ebuf[3] = len & 0xff;
 417         len = ebuflen - 0x13;
 418         ebuf[0x11] = (len >> 8) & 0xff;
 419         ebuf[0x12] = len & 0xff;
 420
 421         msg = pkcs7_parse_message(ebuf, ebuflen);
 422
 423         free(ebuf);
 424
 425 out:
 426         if (IS_ERR(msg))
 427                 return NULL;
 428
 429         return msg;
 430 }
 431
 432 /**
 433  * efi_variable_authenticate - authenticate a variable
 434  * @variable:   Variable name in u16
 435  * @vendor:     Guid of variable
 436  * @data_size:  Size of @data
 437  * @data:       Pointer to variable's value
 438  * @given_attr: Attributes to be given at SetVariable()
 439  * @env_attr:   Attributes that an existing variable holds
 440  * @time:       signed time that an existing variable holds
 441  *
 442  * Called by efi_set_variable() to verify that the input is correct.
 443  * Will replace the given data pointer with another that points to
 444  * the actual data to store in the internal memory.
 445  * On success, @data and @data_size will be replaced with variable's
 446  * actual data, excluding authentication data, and its size, and variable's
 447  * attributes and signed time will also be returned in @env_attr and @time,
 448  * respectively.
 449  *
 450  * Return:      EFI_SUCCESS on success, status code (negative) on error
 451  */
 452 static efi_status_t efi_variable_authenticate(u16 *variable,
 453                                               const efi_guid_t *vendor,
 454                                               efi_uintn_t *data_size,
 455                                               const void **data, u32 given_attr,
 456                                               u32 *env_attr, u64 *time)
 457 {
 458         const struct efi_variable_authentication_2 *auth;
 459         struct efi_signature_store *truststore, *truststore2;
 460         struct pkcs7_message *var_sig;
 461         struct efi_image_regions *regs;
 462         struct efi_time timestamp;
 463         struct rtc_time tm;
 464         u64 new_time;
 465         efi_status_t ret;
 466
 467         var_sig = NULL;
 468         truststore = NULL;
 469         truststore2 = NULL;
 470         regs = NULL;
 471         ret = EFI_SECURITY_VIOLATION;
 472
 473         if (*data_size < sizeof(struct efi_variable_authentication_2))
 474                 goto err;
 475
 476         /* authentication data */
 477         auth = *data;
 478         if (*data_size < (sizeof(auth->time_stamp)
 479                                 + auth->auth_info.hdr.dwLength))
 480                 goto err;
 481
 482         if (guidcmp(&auth->auth_info.cert_type, &efi_guid_cert_type_pkcs7))
 483                 goto err;
 484
 485         *data += sizeof(auth->time_stamp) + auth->auth_info.hdr.dwLength;
 486         *data_size -= (sizeof(auth->time_stamp)
 487                                 + auth->auth_info.hdr.dwLength);
 488
 489         memcpy(&timestamp, &auth->time_stamp, sizeof(timestamp));
 490         memset(&tm, 0, sizeof(tm));
 491         tm.tm_year = timestamp.year;
 492         tm.tm_mon = timestamp.month;
 493         tm.tm_mday = timestamp.day;
 494         tm.tm_hour = timestamp.hour;
 495         tm.tm_min = timestamp.minute;
 496         tm.tm_sec = timestamp.second;
 497         new_time = rtc_mktime(&tm);
 498
 499         if (!efi_secure_boot_enabled()) {
 500                 /* finished checking */
 501                 *time = new_time;
 502                 return EFI_SUCCESS;
 503         }
 504
 505         if (new_time <= *time)
 506                 goto err;
 507
 508         /* data to be digested */
 509         regs = calloc(sizeof(*regs) + sizeof(struct image_region) * 5, 1);
 510         if (!regs)
 511                 goto err;
 512         regs->max = 5;
 513         efi_image_region_add(regs, (uint8_t *)variable,
 514                              (uint8_t *)variable
 515                                 + u16_strlen(variable) * sizeof(u16), 1);
 516         efi_image_region_add(regs, (uint8_t *)vendor,
 517                              (uint8_t *)vendor + sizeof(*vendor), 1);
 518         efi_image_region_add(regs, (uint8_t *)&given_attr,
 519                              (uint8_t *)&given_attr + sizeof(given_attr), 1);
 520         efi_image_region_add(regs, (uint8_t *)&timestamp,
 521                              (uint8_t *)&timestamp + sizeof(timestamp), 1);
 522         efi_image_region_add(regs, (uint8_t *)*data,
 523                              (uint8_t *)*data + *data_size, 1);
 524
 525         /* variable's signature list */
 526         if (auth->auth_info.hdr.dwLength < sizeof(auth->auth_info))
 527                 goto err;
 528         var_sig = efi_variable_parse_signature(auth->auth_info.cert_data,
 529                                                auth->auth_info.hdr.dwLength
 530                                                    - sizeof(auth->auth_info));
 531         if (IS_ERR(var_sig)) {
 532                 debug("Parsing variable's signature failed\n");
 533                 var_sig = NULL;
 534                 goto err;
 535         }
 536
 537         /* signature database used for authentication */
 538         if (u16_strcmp(variable, L"PK") == 0 ||
 539             u16_strcmp(variable, L"KEK") == 0) {
 540                 /* with PK */
 541                 truststore = efi_sigstore_parse_sigdb(L"PK");
 542                 if (!truststore)
 543                         goto err;
 544         } else if (u16_strcmp(variable, L"db") == 0 ||
 545                    u16_strcmp(variable, L"dbx") == 0) {
 546                 /* with PK and KEK */
 547                 truststore = efi_sigstore_parse_sigdb(L"KEK");
 548                 truststore2 = efi_sigstore_parse_sigdb(L"PK");
 549
 550                 if (!truststore) {
 551                         if (!truststore2)
 552                                 goto err;
 553
 554                         truststore = truststore2;
 555                         truststore2 = NULL;
 556                 }
 557         } else {
 558                 /* TODO: support private authenticated variables */
 559                 goto err;
 560         }
 561
 562         /* verify signature */
 563         if (efi_signature_verify_with_sigdb(regs, var_sig, truststore, NULL)) {
 564                 debug("Verified\n");
 565         } else {
 566                 if (truststore2 &&
 567                     efi_signature_verify_with_sigdb(regs, var_sig,
 568                                                     truststore2, NULL)) {
 569                         debug("Verified\n");
 570                 } else {
 571                         debug("Verifying variable's signature failed\n");
 572                         goto err;
 573                 }
 574         }
 575
 576         /* finished checking */
 577         *time = rtc_mktime(&tm);
 578         ret = EFI_SUCCESS;
 579
 580 err:
 581         efi_sigstore_free(truststore);
 582         efi_sigstore_free(truststore2);
 583         pkcs7_free_message(var_sig);
 584         free(regs);
 585
 586         return ret;
 587 }
 588 #else
 589 static efi_status_t efi_variable_authenticate(u16 *variable,
 590                                               const efi_guid_t *vendor,
 591                                               efi_uintn_t *data_size,
 592                                               const void **data, u32 given_attr,
 593                                               u32 *env_attr, u64 *time)
 594 {
 595         return EFI_SUCCESS;
 596 }
 597 #endif /* CONFIG_EFI_SECURE_BOOT */
 598
 599 static
 600 efi_status_t EFIAPI efi_get_variable_common(u16 *variable_name,
 601                                             const efi_guid_t *vendor,
 602                                             u32 *attributes,
 603                                             efi_uintn_t *data_size, void *data)
 604 {
 605         char *native_name;
 606         efi_status_t ret;
 607         unsigned long in_size;
 608         const char *val = NULL, *s;
 609         u64 time = 0;
 610         u32 attr;
 611
 612         if (!variable_name || !vendor || !data_size)
 613                 return EFI_EXIT(EFI_INVALID_PARAMETER);
 614
 615         ret = efi_to_native(&native_name, variable_name, vendor);
 616         if (ret)
 617                 return ret;
 618
 619         EFI_PRINT("get '%s'\n", native_name);
 620
 621         val = env_get(native_name);
 622         free(native_name);
 623         if (!val)
 624                 return EFI_NOT_FOUND;
 625
 626         val = parse_attr(val, &attr, &time);
 627
 628         in_size = *data_size;
 629
 630         if ((s = prefix(val, "(blob)"))) {
 631                 size_t len = strlen(s);
 632
 633                 /* number of hexadecimal digits must be even */
 634                 if (len & 1)
 635                         return EFI_DEVICE_ERROR;
 636
 637                 /* two characters per byte: */
 638                 len /= 2;
 639                 *data_size = len;
 640
 641                 if (in_size < len) {
 642                         ret = EFI_BUFFER_TOO_SMALL;
 643                         goto out;
 644                 }
 645
 646                 if (!data) {
 647                         debug("Variable with no data shouldn't exist.\n");
 648                         return EFI_INVALID_PARAMETER;
 649                 }
 650
 651                 if (hex2bin(data, s, len))
 652                         return EFI_DEVICE_ERROR;
 653
 654                 EFI_PRINT("got value: \"%s\"\n", s);
 655         } else if ((s = prefix(val, "(utf8)"))) {
 656                 unsigned len = strlen(s) + 1;
 657
 658                 *data_size = len;
 659
 660                 if (in_size < len) {
 661                         ret = EFI_BUFFER_TOO_SMALL;
 662                         goto out;
 663                 }
 664
 665                 if (!data) {
 666                         debug("Variable with no data shouldn't exist.\n");
 667                         return EFI_INVALID_PARAMETER;
 668                 }
 669
 670                 memcpy(data, s, len);
 671                 ((char *)data)[len] = '\0';
 672
 673                 EFI_PRINT("got value: \"%s\"\n", (char *)data);
 674         } else {
 675                 EFI_PRINT("invalid value: '%s'\n", val);
 676                 return EFI_DEVICE_ERROR;
 677         }
 678
 679 out:
 680         if (attributes)
 681                 *attributes = attr & EFI_VARIABLE_MASK;
 682
 683         return ret;
 684 }
 685
 686 /**
 687  * efi_efi_get_variable() - retrieve value of a UEFI variable
 688  *
 689  * This function implements the GetVariable runtime service.
 690  *
 691  * See the Unified Extensible Firmware Interface (UEFI) specification for
 692  * details.
 693  *
 694  * @variable_name:      name of the variable
 695  * @vendor:             vendor GUID
 696  * @attributes:         attributes of the variable
 697  * @data_size:          size of the buffer to which the variable value is copied
 698  * @data:               buffer to which the variable value is copied
 699  * Return:              status code
 700  */
 701 efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
 702                                      const efi_guid_t *vendor, u32 *attributes,
 703                                      efi_uintn_t *data_size, void *data)
 704 {
 705         efi_status_t ret;
 706
 707         EFI_ENTRY("\"%ls\" %pUl %p %p %p", variable_name, vendor, attributes,
 708                   data_size, data);
 709
 710         ret = efi_get_variable_common(variable_name, vendor, attributes,
 711                                       data_size, data);
 712         return EFI_EXIT(ret);
 713 }
 714
 715 static char *efi_variables_list;
 716 static char *efi_cur_variable;
 717
 718 /**
 719  * parse_uboot_variable() - parse a u-boot variable and get uefi-related
 720  *                          information
 721  * @variable:           whole data of u-boot variable (ie. name=value)
 722  * @variable_name_size: size of variable_name buffer in byte
 723  * @variable_name:      name of uefi variable in u16, null-terminated
 724  * @vendor:             vendor's guid
 725  * @attributes:         attributes
 726  *
 727  * A uefi variable is encoded into a u-boot variable as described above.
 728  * This function parses such a u-boot variable and retrieve uefi-related
 729  * information into respective parameters. In return, variable_name_size
 730  * is the size of variable name including NULL.
 731  *
 732  * Return:              EFI_SUCCESS if parsing is OK, EFI_NOT_FOUND when
 733  *                      the entire variable list has been returned,
 734  *                      otherwise non-zero status code
 735  */
 736 static efi_status_t parse_uboot_variable(char *variable,
 737                                          efi_uintn_t *variable_name_size,
 738                                          u16 *variable_name,
 739                                          const efi_guid_t *vendor,
 740                                          u32 *attributes)
 741 {
 742         char *guid, *name, *end, c;
 743         size_t name_len;
 744         efi_uintn_t old_variable_name_size;
 745         u64 time;
 746         u16 *p;
 747
 748         guid = strchr(variable, '_');
 749         if (!guid)
 750                 return EFI_INVALID_PARAMETER;
 751         guid++;
 752         name = strchr(guid, '_');
 753         if (!name)
 754                 return EFI_INVALID_PARAMETER;
 755         name++;
 756         end = strchr(name, '=');
 757         if (!end)
 758                 return EFI_INVALID_PARAMETER;
 759
 760         name_len = end - name;
 761         old_variable_name_size = *variable_name_size;
 762         *variable_name_size = sizeof(u16) * (name_len + 1);
 763         if (old_variable_name_size < *variable_name_size)
 764                 return EFI_BUFFER_TOO_SMALL;
 765
 766         end++; /* point to value */
 767
 768         /* variable name */
 769         p = variable_name;
 770         utf8_utf16_strncpy(&p, name, name_len);
 771         variable_name[name_len] = 0;
 772
 773         /* guid */
 774         c = *(name - 1);
 775         *(name - 1) = '\0'; /* guid need be null-terminated here */
 776         uuid_str_to_bin(guid, (unsigned char *)vendor, UUID_STR_FORMAT_GUID);
 777         *(name - 1) = c;
 778
 779         /* attributes */
 780         parse_attr(end, attributes, &time);
 781
 782         return EFI_SUCCESS;
 783 }
 784
 785 /**
 786  * efi_get_next_variable_name() - enumerate the current variable names
 787  *
 788  * @variable_name_size: size of variable_name buffer in byte
 789  * @variable_name:      name of uefi variable's name in u16
 790  * @vendor:             vendor's guid
 791  *
 792  * This function implements the GetNextVariableName service.
 793  *
 794  * See the Unified Extensible Firmware Interface (UEFI) specification for
 795  * details.
 796  *
 797  * Return: status code
 798  */
 799 efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
 800                                                u16 *variable_name,
 801                                                efi_guid_t *vendor)
 802 {
 803         char *native_name, *variable;
 804         ssize_t name_len, list_len;
 805         char regex[256];
 806         char * const regexlist[] = {regex};
 807         u32 attributes;
 808         int i;
 809         efi_status_t ret;
 810
 811         EFI_ENTRY("%p \"%ls\" %pUl", variable_name_size, variable_name, vendor);
 812
 813         if (!variable_name_size || !variable_name || !vendor)
 814                 return EFI_EXIT(EFI_INVALID_PARAMETER);
 815
 816         if (variable_name[0]) {
 817                 /* check null-terminated string */
 818                 for (i = 0; i < *variable_name_size; i++)
 819                         if (!variable_name[i])
 820                                 break;
 821                 if (i >= *variable_name_size)
 822                         return EFI_EXIT(EFI_INVALID_PARAMETER);
 823
 824                 /* search for the last-returned variable */
 825                 ret = efi_to_native(&native_name, variable_name, vendor);
 826                 if (ret)
 827                         return EFI_EXIT(ret);
 828
 829                 name_len = strlen(native_name);
 830                 for (variable = efi_variables_list; variable && *variable;) {
 831                         if (!strncmp(variable, native_name, name_len) &&
 832                             variable[name_len] == '=')
 833                                 break;
 834
 835                         variable = strchr(variable, '\n');
 836                         if (variable)
 837                                 variable++;
 838                 }
 839
 840                 free(native_name);
 841                 if (!(variable && *variable))
 842                         return EFI_EXIT(EFI_INVALID_PARAMETER);
 843
 844                 /* next variable */
 845                 variable = strchr(variable, '\n');
 846                 if (variable)
 847                         variable++;
 848                 if (!(variable && *variable))
 849                         return EFI_EXIT(EFI_NOT_FOUND);
 850         } else {
 851                 /*
 852                  *new search: free a list used in the previous search
 853                  */
 854                 free(efi_variables_list);
 855                 efi_variables_list = NULL;
 856                 efi_cur_variable = NULL;
 857
 858                 snprintf(regex, 256, "efi_.*-.*-.*-.*-.*_.*");
 859                 list_len = hexport_r(&env_htab, '\n',
 860                                      H_MATCH_REGEX | H_MATCH_KEY,
 861                                      &efi_variables_list, 0, 1, regexlist);
 862
 863                 if (list_len <= 1)
 864                         return EFI_EXIT(EFI_NOT_FOUND);
 865
 866                 variable = efi_variables_list;
 867         }
 868
 869         ret = parse_uboot_variable(variable, variable_name_size, variable_name,
 870                                    vendor, &attributes);
 871
 872         return EFI_EXIT(ret);
 873 }
 874
 875 static
 876 efi_status_t EFIAPI efi_set_variable_common(u16 *variable_name,
 877                                             const efi_guid_t *vendor,
 878                                             u32 attributes,
 879                                             efi_uintn_t data_size,
 880                                             const void *data,
 881                                             bool ro_check,
 882                                             bool is_non_volatile)
 883 {
 884         char *native_name = NULL, *old_data = NULL, *val = NULL, *s;
 885         efi_uintn_t old_size;
 886         bool append, delete;
 887         u64 time = 0;
 888         u32 attr;
 889         efi_status_t ret = EFI_SUCCESS;
 890
 891         debug("%s: set '%s'\n", __func__, native_name);
 892
 893         if (!variable_name || !*variable_name || !vendor ||
 894             ((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
 895              !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS))) {
 896                 ret = EFI_INVALID_PARAMETER;
 897                 goto err;
 898         }
 899
 900         ret = efi_to_native(&native_name, variable_name, vendor);
 901         if (ret)
 902                 goto err;
 903
 904         /* check if a variable exists */
 905         old_size = 0;
 906         attr = 0;
 907         ret = EFI_CALL(efi_get_variable(variable_name, vendor, &attr,
 908                                         &old_size, NULL));
 909         if (ret == EFI_BUFFER_TOO_SMALL) {
 910                 if ((is_non_volatile && !(attr & EFI_VARIABLE_NON_VOLATILE)) ||
 911                     (!is_non_volatile && (attr & EFI_VARIABLE_NON_VOLATILE))) {
 912                         ret = EFI_INVALID_PARAMETER;
 913                         goto err;
 914                 }
 915         }
 916
 917         append = !!(attributes & EFI_VARIABLE_APPEND_WRITE);
 918         attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE;
 919         delete = !append && (!data_size || !attributes);
 920
 921         /* check attributes */
 922         if (old_size) {
 923                 if (ro_check && (attr & READ_ONLY)) {
 924                         ret = EFI_WRITE_PROTECTED;
 925                         goto err;
 926                 }
 927
 928                 /* attributes won't be changed */
 929                 if (!delete &&
 930                     ((ro_check && attr != attributes) ||
 931                      (!ro_check && ((attr & ~(u32)READ_ONLY)
 932                                     != (attributes & ~(u32)READ_ONLY))))) {
 933                         ret = EFI_INVALID_PARAMETER;
 934                         goto err;
 935                 }
 936         } else {
 937                 if (delete || append) {
 938                         /*
 939                          * Trying to delete or to update a non-existent
 940                          * variable.
 941                          */
 942                         ret = EFI_NOT_FOUND;
 943                         goto err;
 944                 }
 945         }
 946
 947         if (((!u16_strcmp(variable_name, L"PK") ||
 948               !u16_strcmp(variable_name, L"KEK")) &&
 949                 !guidcmp(vendor, &efi_global_variable_guid)) ||
 950             ((!u16_strcmp(variable_name, L"db") ||
 951               !u16_strcmp(variable_name, L"dbx")) &&
 952                 !guidcmp(vendor, &efi_guid_image_security_database))) {
 953                 /* authentication is mandatory */
 954                 if (!(attributes &
 955                       EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
 956                         debug("%ls: AUTHENTICATED_WRITE_ACCESS required\n",
 957                               variable_name);
 958                         ret = EFI_INVALID_PARAMETER;
 959                         goto err;
 960                 }
 961         }
 962
 963         /* authenticate a variable */
 964         if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {
 965                 if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) {
 966                         ret = EFI_INVALID_PARAMETER;
 967                         goto err;
 968                 }
 969                 if (attributes &
 970                     EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
 971                         ret = efi_variable_authenticate(variable_name, vendor,
 972                                                         &data_size, &data,
 973                                                         attributes, &attr,
 974                                                         &time);
 975                         if (ret != EFI_SUCCESS)
 976                                 goto err;
 977
 978                         /* last chance to check for delete */
 979                         if (!data_size)
 980                                 delete = true;
 981                 }
 982         } else {
 983                 if (attributes &
 984                     (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
 985                      EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
 986                         debug("Secure boot is not configured\n");
 987                         ret = EFI_INVALID_PARAMETER;
 988                         goto err;
 989                 }
 990         }
 991
 992         /* delete a variable */
 993         if (delete) {
 994                 /* !old_size case has been handled before */
 995                 val = NULL;
 996                 ret = EFI_SUCCESS;
 997                 goto out;
 998         }
 999
1000         if (append) {
1001                 old_data = malloc(old_size);
1002                 if (!old_data) {
1003                         return EFI_OUT_OF_RESOURCES;
1004                         goto err;
1005                 }
1006                 ret = EFI_CALL(efi_get_variable(variable_name, vendor,
1007                                                 &attr, &old_size, old_data));
1008                 if (ret != EFI_SUCCESS)
1009                         goto err;
1010         } else {
1011                 old_size = 0;
1012         }
1013
1014         val = malloc(2 * old_size + 2 * data_size
1015                      + strlen("{ro,run,boot,nv,time=0123456701234567}(blob)")
1016                      + 1);
1017         if (!val) {
1018                 ret = EFI_OUT_OF_RESOURCES;
1019                 goto err;
1020         }
1021
1022         s = val;
1023
1024         /*
1025          * store attributes
1026          */
1027         attributes &= (READ_ONLY |
1028                        EFI_VARIABLE_NON_VOLATILE |
1029                        EFI_VARIABLE_BOOTSERVICE_ACCESS |
1030                        EFI_VARIABLE_RUNTIME_ACCESS |
1031                        EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS);
1032         s += sprintf(s, "{");
1033         while (attributes) {
1034                 attr = 1 << (ffs(attributes) - 1);
1035
1036                 if (attr == READ_ONLY) {
1037                         s += sprintf(s, "ro");
1038                 } else if (attr == EFI_VARIABLE_NON_VOLATILE) {
1039                         s += sprintf(s, "nv");
1040                 } else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS) {
1041                         s += sprintf(s, "boot");
1042                 } else if (attr == EFI_VARIABLE_RUNTIME_ACCESS) {
1043                         s += sprintf(s, "run");
1044                 } else if (attr ==
1045                            EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
1046                         s += sprintf(s, "time=");
1047                         s = bin2hex(s, (u8 *)&time, sizeof(time));
1048                 }
1049
1050                 attributes &= ~attr;
1051                 if (attributes)
1052                         s += sprintf(s, ",");
1053         }
1054         s += sprintf(s, "}");
1055         s += sprintf(s, "(blob)");
1056
1057         /* store payload: */
1058         if (append)
1059                 s = bin2hex(s, old_data, old_size);
1060         s = bin2hex(s, data, data_size);
1061         *s = '\0';
1062
1063         EFI_PRINT("setting: %s=%s\n", native_name, val);
1064
1065 out:
1066         if (env_set(native_name, val)) {
1067                 ret = EFI_DEVICE_ERROR;
1068         } else {
1069                 bool vendor_keys_modified = false;
1070
1071                 if ((u16_strcmp(variable_name, L"PK") == 0 &&
1072                      guidcmp(vendor, &efi_global_variable_guid) == 0)) {
1073                         ret = efi_transfer_secure_state(
1074                                         (delete ? EFI_MODE_SETUP :
1075                                                   EFI_MODE_USER));
1076                         if (ret != EFI_SUCCESS)
1077                                 goto err;
1078
1079                         if (efi_secure_mode != EFI_MODE_SETUP)
1080                                 vendor_keys_modified = true;
1081                 } else if ((u16_strcmp(variable_name, L"KEK") == 0 &&
1082                      guidcmp(vendor, &efi_global_variable_guid) == 0)) {
1083                         if (efi_secure_mode != EFI_MODE_SETUP)
1084                                 vendor_keys_modified = true;
1085                 }
1086
1087                 /* update VendorKeys */
1088                 if (vendor_keys_modified & efi_vendor_keys) {
1089                         efi_vendor_keys = 0;
1090                         ret = efi_set_variable_internal(
1091                                                 L"VendorKeys",
1092                                                 &efi_global_variable_guid,
1093                                                 EFI_VARIABLE_BOOTSERVICE_ACCESS
1094                                                  | EFI_VARIABLE_RUNTIME_ACCESS
1095                                                  | READ_ONLY,
1096                                                 sizeof(efi_vendor_keys),
1097                                                 &efi_vendor_keys,
1098                                                 false);
1099                 } else {
1100                         ret = EFI_SUCCESS;
1101                 }
1102         }
1103
1104 err:
1105         free(native_name);
1106         free(old_data);
1107         free(val);
1108
1109         return ret;
1110 }
1111
1112 static
1113 efi_status_t EFIAPI efi_set_volatile_variable(u16 *variable_name,
1114                                               const efi_guid_t *vendor,
1115                                               u32 attributes,
1116                                               efi_uintn_t data_size,
1117                                               const void *data,
1118                                               bool ro_check)
1119 {
1120         return efi_set_variable_common(variable_name, vendor, attributes,
1121                                        data_size, data, ro_check, false);
1122 }
1123
1124 efi_status_t EFIAPI efi_set_nonvolatile_variable(u16 *variable_name,
1125                                                  const efi_guid_t *vendor,
1126                                                  u32 attributes,
1127                                                  efi_uintn_t data_size,
1128                                                  const void *data,
1129                                                  bool ro_check)
1130 {
1131         efi_status_t ret;
1132
1133         ret = efi_set_variable_common(variable_name, vendor, attributes,
1134                                       data_size, data, ro_check, true);
1135
1136         return ret;
1137 }
1138
1139 static efi_status_t efi_set_variable_internal(u16 *variable_name,
1140                                               const efi_guid_t *vendor,
1141                                               u32 attributes,
1142                                               efi_uintn_t data_size,
1143                                               const void *data,
1144                                               bool ro_check)
1145 {
1146         efi_status_t ret;
1147
1148         if (attributes & EFI_VARIABLE_NON_VOLATILE)
1149                 ret = efi_set_nonvolatile_variable(variable_name, vendor,
1150                                                    attributes,
1151                                                    data_size, data, ro_check);
1152         else
1153                 ret = efi_set_volatile_variable(variable_name, vendor,
1154                                                 attributes, data_size, data,
1155                                                 ro_check);
1156
1157         return ret;
1158 }
1159
1160 /**
1161  * efi_set_variable() - set value of a UEFI variable
1162  *
1163  * This function implements the SetVariable runtime service.
1164  *
1165  * See the Unified Extensible Firmware Interface (UEFI) specification for
1166  * details.
1167  *
1168  * @variable_name:      name of the variable
1169  * @vendor:             vendor GUID
1170  * @attributes:         attributes of the variable
1171  * @data_size:          size of the buffer with the variable value
1172  * @data:               buffer with the variable value
1173  * Return:              status code
1174  */
1175 efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
1176                                      const efi_guid_t *vendor, u32 attributes,
1177                                      efi_uintn_t data_size, const void *data)
1178 {
1179         EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
1180                   data_size, data);
1181
1182         /* READ_ONLY bit is not part of API */
1183         attributes &= ~(u32)READ_ONLY;
1184
1185         return EFI_EXIT(efi_set_variable_internal(variable_name, vendor,
1186                                                   attributes, data_size, data,
1187                                                   true));
1188 }
1189
1190 /**
1191  * efi_query_variable_info() - get information about EFI variables
1192  *
1193  * This function implements the QueryVariableInfo() runtime service.
1194  *
1195  * See the Unified Extensible Firmware Interface (UEFI) specification for
1196  * details.
1197  *
1198  * @attributes:                         bitmask to select variables to be
1199  *                                      queried
1200  * @maximum_variable_storage_size:      maximum size of storage area for the
1201  *                                      selected variable types
1202  * @remaining_variable_storage_size:    remaining size of storage are for the
1203  *                                      selected variable types
1204  * @maximum_variable_size:              maximum size of a variable of the
1205  *                                      selected type
1206  * Returns:                             status code
1207  */
1208 efi_status_t __efi_runtime EFIAPI efi_query_variable_info(
1209                         u32 attributes,
1210                         u64 *maximum_variable_storage_size,
1211                         u64 *remaining_variable_storage_size,
1212                         u64 *maximum_variable_size)
1213 {
1214         return EFI_UNSUPPORTED;
1215 }
1216
1217 /**
1218  * efi_get_variable_runtime() - runtime implementation of GetVariable()
1219  *
1220  * @variable_name:      name of the variable
1221  * @vendor:             vendor GUID
1222  * @attributes:         attributes of the variable
1223  * @data_size:          size of the buffer to which the variable value is copied
1224  * @data:               buffer to which the variable value is copied
1225  * Return:              status code
1226  */
1227 static efi_status_t __efi_runtime EFIAPI
1228 efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
1229                          u32 *attributes, efi_uintn_t *data_size, void *data)
1230 {
1231         return EFI_UNSUPPORTED;
1232 }
1233
1234 /**
1235  * efi_get_next_variable_name_runtime() - runtime implementation of
1236  *                                        GetNextVariable()
1237  *
1238  * @variable_name_size: size of variable_name buffer in byte
1239  * @variable_name:      name of uefi variable's name in u16
1240  * @vendor:             vendor's guid
1241  * Return: status code
1242  */
1243 static efi_status_t __efi_runtime EFIAPI
1244 efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
1245                                    u16 *variable_name, efi_guid_t *vendor)
1246 {
1247         return EFI_UNSUPPORTED;
1248 }
1249
1250 /**
1251  * efi_set_variable_runtime() - runtime implementation of SetVariable()
1252  *
1253  * @variable_name:      name of the variable
1254  * @vendor:             vendor GUID
1255  * @attributes:         attributes of the variable
1256  * @data_size:          size of the buffer with the variable value
1257  * @data:               buffer with the variable value
1258  * Return:              status code
1259  */
1260 static efi_status_t __efi_runtime EFIAPI
1261 efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
1262                          u32 attributes, efi_uintn_t data_size,
1263                          const void *data)
1264 {
1265         return EFI_UNSUPPORTED;
1266 }
1267
1268 /**
1269  * efi_variables_boot_exit_notify() - notify ExitBootServices() is called
1270  */
1271 void efi_variables_boot_exit_notify(void)
1272 {
1273         efi_runtime_services.get_variable = efi_get_variable_runtime;
1274         efi_runtime_services.get_next_variable_name =
1275                                 efi_get_next_variable_name_runtime;
1276         efi_runtime_services.set_variable = efi_set_variable_runtime;
1277         efi_update_table_header_crc32(&efi_runtime_services.hdr);
1278 }
1279
1280 /**
1281  * efi_init_variables() - initialize variable services
1282  *
1283  * Return:      status code
1284  */
1285 efi_status_t efi_init_variables(void)
1286 {
1287         efi_status_t ret;
1288
1289         ret = efi_init_secure_state();
1290
1291         return ret;
1292 }