| 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* |
| 3 | * Originally from efivars.c |
| 4 | * |
| 5 | * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> |
| 6 | * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> |
| 7 | */ |
| 8 | |
| 9 | #include <linux/capability.h> |
| 10 | #include <linux/types.h> |
| 11 | #include <linux/errno.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/mm.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/string.h> |
| 16 | #include <linux/smp.h> |
| 17 | #include <linux/efi.h> |
| 18 | #include <linux/device.h> |
| 19 | #include <linux/slab.h> |
| 20 | #include <linux/ctype.h> |
| 21 | #include <linux/ucs2_string.h> |
| 22 | |
| 23 | #include "internal.h" |
| 24 | |
| 25 | MODULE_IMPORT_NS(EFIVAR); |
| 26 | |
| 27 | static bool |
| 28 | validate_device_path(efi_char16_t *var_name, int match, u8 *buffer, |
| 29 | unsigned long len) |
| 30 | { |
| 31 | struct efi_generic_dev_path *node; |
| 32 | int offset = 0; |
| 33 | |
| 34 | node = (struct efi_generic_dev_path *)buffer; |
| 35 | |
| 36 | if (len < sizeof(*node)) |
| 37 | return false; |
| 38 | |
| 39 | while (offset <= len - sizeof(*node) && |
| 40 | node->length >= sizeof(*node) && |
| 41 | node->length <= len - offset) { |
| 42 | offset += node->length; |
| 43 | |
| 44 | if ((node->type == EFI_DEV_END_PATH || |
| 45 | node->type == EFI_DEV_END_PATH2) && |
| 46 | node->sub_type == EFI_DEV_END_ENTIRE) |
| 47 | return true; |
| 48 | |
| 49 | node = (struct efi_generic_dev_path *)(buffer + offset); |
| 50 | } |
| 51 | |
| 52 | /* |
| 53 | * If we're here then either node->length pointed past the end |
| 54 | * of the buffer or we reached the end of the buffer without |
| 55 | * finding a device path end node. |
| 56 | */ |
| 57 | return false; |
| 58 | } |
| 59 | |
| 60 | static bool |
| 61 | validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer, |
| 62 | unsigned long len) |
| 63 | { |
| 64 | /* An array of 16-bit integers */ |
| 65 | if ((len % 2) != 0) |
| 66 | return false; |
| 67 | |
| 68 | return true; |
| 69 | } |
| 70 | |
| 71 | static bool |
| 72 | validate_load_option(efi_char16_t *var_name, int match, u8 *buffer, |
| 73 | unsigned long len) |
| 74 | { |
| 75 | u16 filepathlength; |
| 76 | int i, desclength = 0, namelen; |
| 77 | |
| 78 | namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN); |
| 79 | |
| 80 | /* Either "Boot" or "Driver" followed by four digits of hex */ |
| 81 | for (i = match; i < match+4; i++) { |
| 82 | if (var_name[i] > 127 || |
| 83 | hex_to_bin(var_name[i] & 0xff) < 0) |
| 84 | return true; |
| 85 | } |
| 86 | |
| 87 | /* Reject it if there's 4 digits of hex and then further content */ |
| 88 | if (namelen > match + 4) |
| 89 | return false; |
| 90 | |
| 91 | /* A valid entry must be at least 8 bytes */ |
| 92 | if (len < 8) |
| 93 | return false; |
| 94 | |
| 95 | filepathlength = buffer[4] | buffer[5] << 8; |
| 96 | |
| 97 | /* |
| 98 | * There's no stored length for the description, so it has to be |
| 99 | * found by hand |
| 100 | */ |
| 101 | desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; |
| 102 | |
| 103 | /* Each boot entry must have a descriptor */ |
| 104 | if (!desclength) |
| 105 | return false; |
| 106 | |
| 107 | /* |
| 108 | * If the sum of the length of the description, the claimed filepath |
| 109 | * length and the original header are greater than the length of the |
| 110 | * variable, it's malformed |
| 111 | */ |
| 112 | if ((desclength + filepathlength + 6) > len) |
| 113 | return false; |
| 114 | |
| 115 | /* |
| 116 | * And, finally, check the filepath |
| 117 | */ |
| 118 | return validate_device_path(var_name, match, buffer + desclength + 6, |
| 119 | filepathlength); |
| 120 | } |
| 121 | |
| 122 | static bool |
| 123 | validate_uint16(efi_char16_t *var_name, int match, u8 *buffer, |
| 124 | unsigned long len) |
| 125 | { |
| 126 | /* A single 16-bit integer */ |
| 127 | if (len != 2) |
| 128 | return false; |
| 129 | |
| 130 | return true; |
| 131 | } |
| 132 | |
| 133 | static bool |
| 134 | validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, |
| 135 | unsigned long len) |
| 136 | { |
| 137 | int i; |
| 138 | |
| 139 | for (i = 0; i < len; i++) { |
| 140 | if (buffer[i] > 127) |
| 141 | return false; |
| 142 | |
| 143 | if (buffer[i] == 0) |
| 144 | return true; |
| 145 | } |
| 146 | |
| 147 | return false; |
| 148 | } |
| 149 | |
| 150 | struct variable_validate { |
| 151 | efi_guid_t vendor; |
| 152 | char *name; |
| 153 | bool (*validate)(efi_char16_t *var_name, int match, u8 *data, |
| 154 | unsigned long len); |
| 155 | }; |
| 156 | |
| 157 | /* |
| 158 | * This is the list of variables we need to validate, as well as the |
| 159 | * whitelist for what we think is safe not to default to immutable. |
| 160 | * |
| 161 | * If it has a validate() method that's not NULL, it'll go into the |
| 162 | * validation routine. If not, it is assumed valid, but still used for |
| 163 | * whitelisting. |
| 164 | * |
| 165 | * Note that it's sorted by {vendor,name}, but globbed names must come after |
| 166 | * any other name with the same prefix. |
| 167 | */ |
| 168 | static const struct variable_validate variable_validate[] = { |
| 169 | { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, |
| 170 | { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, |
| 171 | { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, |
| 172 | { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, |
| 173 | { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, |
| 174 | { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, |
| 175 | { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, |
| 176 | { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, |
| 177 | { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, |
| 178 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, |
| 179 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, |
| 180 | { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, |
| 181 | { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, |
| 182 | { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, |
| 183 | { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, |
| 184 | { LINUX_EFI_CRASH_GUID, "*", NULL }, |
| 185 | { NULL_GUID, "", NULL }, |
| 186 | }; |
| 187 | |
| 188 | /* |
| 189 | * Check if @var_name matches the pattern given in @match_name. |
| 190 | * |
| 191 | * @var_name: an array of @len non-NUL characters. |
| 192 | * @match_name: a NUL-terminated pattern string, optionally ending in "*". A |
| 193 | * final "*" character matches any trailing characters @var_name, |
| 194 | * including the case when there are none left in @var_name. |
| 195 | * @match: on output, the number of non-wildcard characters in @match_name |
| 196 | * that @var_name matches, regardless of the return value. |
| 197 | * @return: whether @var_name fully matches @match_name. |
| 198 | */ |
| 199 | static bool |
| 200 | variable_matches(const char *var_name, size_t len, const char *match_name, |
| 201 | int *match) |
| 202 | { |
| 203 | for (*match = 0; ; (*match)++) { |
| 204 | char c = match_name[*match]; |
| 205 | |
| 206 | switch (c) { |
| 207 | case '*': |
| 208 | /* Wildcard in @match_name means we've matched. */ |
| 209 | return true; |
| 210 | |
| 211 | case '\0': |
| 212 | /* @match_name has ended. Has @var_name too? */ |
| 213 | return (*match == len); |
| 214 | |
| 215 | default: |
| 216 | /* |
| 217 | * We've reached a non-wildcard char in @match_name. |
| 218 | * Continue only if there's an identical character in |
| 219 | * @var_name. |
| 220 | */ |
| 221 | if (*match < len && c == var_name[*match]) |
| 222 | continue; |
| 223 | return false; |
| 224 | } |
| 225 | } |
| 226 | } |
| 227 | |
| 228 | bool |
| 229 | efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, |
| 230 | unsigned long data_size) |
| 231 | { |
| 232 | int i; |
| 233 | unsigned long utf8_size; |
| 234 | u8 *utf8_name; |
| 235 | |
| 236 | utf8_size = ucs2_utf8size(var_name); |
| 237 | utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); |
| 238 | if (!utf8_name) |
| 239 | return false; |
| 240 | |
| 241 | ucs2_as_utf8(utf8_name, var_name, utf8_size); |
| 242 | utf8_name[utf8_size] = '\0'; |
| 243 | |
| 244 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
| 245 | const char *name = variable_validate[i].name; |
| 246 | int match = 0; |
| 247 | |
| 248 | if (efi_guidcmp(vendor, variable_validate[i].vendor)) |
| 249 | continue; |
| 250 | |
| 251 | if (variable_matches(utf8_name, utf8_size+1, name, &match)) { |
| 252 | if (variable_validate[i].validate == NULL) |
| 253 | break; |
| 254 | kfree(utf8_name); |
| 255 | return variable_validate[i].validate(var_name, match, |
| 256 | data, data_size); |
| 257 | } |
| 258 | } |
| 259 | kfree(utf8_name); |
| 260 | return true; |
| 261 | } |
| 262 | |
| 263 | bool |
| 264 | efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, |
| 265 | size_t len) |
| 266 | { |
| 267 | int i; |
| 268 | bool found = false; |
| 269 | int match = 0; |
| 270 | |
| 271 | /* |
| 272 | * Check if our variable is in the validated variables list |
| 273 | */ |
| 274 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
| 275 | if (efi_guidcmp(variable_validate[i].vendor, vendor)) |
| 276 | continue; |
| 277 | |
| 278 | if (variable_matches(var_name, len, |
| 279 | variable_validate[i].name, &match)) { |
| 280 | found = true; |
| 281 | break; |
| 282 | } |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * If it's in our list, it is removable. |
| 287 | */ |
| 288 | return found; |
| 289 | } |
| 290 | |
| 291 | static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
| 292 | struct list_head *head) |
| 293 | { |
| 294 | struct efivar_entry *entry, *n; |
| 295 | unsigned long strsize1, strsize2; |
| 296 | bool found = false; |
| 297 | |
| 298 | strsize1 = ucs2_strsize(variable_name, EFI_VAR_NAME_LEN); |
| 299 | list_for_each_entry_safe(entry, n, head, list) { |
| 300 | strsize2 = ucs2_strsize(entry->var.VariableName, EFI_VAR_NAME_LEN); |
| 301 | if (strsize1 == strsize2 && |
| 302 | !memcmp(variable_name, &(entry->var.VariableName), |
| 303 | strsize2) && |
| 304 | !efi_guidcmp(entry->var.VendorGuid, |
| 305 | *vendor)) { |
| 306 | found = true; |
| 307 | break; |
| 308 | } |
| 309 | } |
| 310 | return found; |
| 311 | } |
| 312 | |
| 313 | /* |
| 314 | * Returns the size of variable_name, in bytes, including the |
| 315 | * terminating NULL character, or variable_name_size if no NULL |
| 316 | * character is found among the first variable_name_size bytes. |
| 317 | */ |
| 318 | static unsigned long var_name_strnsize(efi_char16_t *variable_name, |
| 319 | unsigned long variable_name_size) |
| 320 | { |
| 321 | unsigned long len; |
| 322 | efi_char16_t c; |
| 323 | |
| 324 | /* |
| 325 | * The variable name is, by definition, a NULL-terminated |
| 326 | * string, so make absolutely sure that variable_name_size is |
| 327 | * the value we expect it to be. If not, return the real size. |
| 328 | */ |
| 329 | for (len = 2; len <= variable_name_size; len += sizeof(c)) { |
| 330 | c = variable_name[(len / sizeof(c)) - 1]; |
| 331 | if (!c) |
| 332 | break; |
| 333 | } |
| 334 | |
| 335 | return min(len, variable_name_size); |
| 336 | } |
| 337 | |
| 338 | /* |
| 339 | * Print a warning when duplicate EFI variables are encountered and |
| 340 | * disable the sysfs workqueue since the firmware is buggy. |
| 341 | */ |
| 342 | static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
| 343 | unsigned long len16) |
| 344 | { |
| 345 | size_t i, len8 = len16 / sizeof(efi_char16_t); |
| 346 | char *str8; |
| 347 | |
| 348 | str8 = kzalloc(len8, GFP_KERNEL); |
| 349 | if (!str8) |
| 350 | return; |
| 351 | |
| 352 | for (i = 0; i < len8; i++) |
| 353 | str8[i] = str16[i]; |
| 354 | |
| 355 | printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", |
| 356 | str8, vendor_guid); |
| 357 | kfree(str8); |
| 358 | } |
| 359 | |
| 360 | /** |
| 361 | * efivar_init - build the initial list of EFI variables |
| 362 | * @func: callback function to invoke for every variable |
| 363 | * @data: function-specific data to pass to @func |
| 364 | * @head: initialised head of variable list |
| 365 | * |
| 366 | * Get every EFI variable from the firmware and invoke @func. @func |
| 367 | * should call efivar_entry_add() to build the list of variables. |
| 368 | * |
| 369 | * Returns 0 on success, or a kernel error code on failure. |
| 370 | */ |
| 371 | int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *, |
| 372 | struct list_head *), |
| 373 | void *data, struct list_head *head) |
| 374 | { |
| 375 | unsigned long variable_name_size = 512; |
| 376 | efi_char16_t *variable_name; |
| 377 | efi_status_t status; |
| 378 | efi_guid_t vendor_guid; |
| 379 | int err = 0; |
| 380 | |
| 381 | variable_name = kzalloc(variable_name_size, GFP_KERNEL); |
| 382 | if (!variable_name) { |
| 383 | printk(KERN_ERR "efivars: Memory allocation failed.\n"); |
| 384 | return -ENOMEM; |
| 385 | } |
| 386 | |
| 387 | err = efivar_lock(); |
| 388 | if (err) |
| 389 | goto free; |
| 390 | |
| 391 | /* |
| 392 | * A small set of old UEFI implementations reject sizes |
| 393 | * above a certain threshold, the lowest seen in the wild |
| 394 | * is 512. |
| 395 | */ |
| 396 | |
| 397 | do { |
| 398 | variable_name_size = 512; |
| 399 | BUILD_BUG_ON(EFI_VAR_NAME_LEN < 512); |
| 400 | |
| 401 | status = efivar_get_next_variable(&variable_name_size, |
| 402 | variable_name, |
| 403 | &vendor_guid); |
| 404 | switch (status) { |
| 405 | case EFI_SUCCESS: |
| 406 | variable_name_size = var_name_strnsize(variable_name, |
| 407 | variable_name_size); |
| 408 | |
| 409 | /* |
| 410 | * Some firmware implementations return the |
| 411 | * same variable name on multiple calls to |
| 412 | * get_next_variable(). Terminate the loop |
| 413 | * immediately as there is no guarantee that |
| 414 | * we'll ever see a different variable name, |
| 415 | * and may end up looping here forever. |
| 416 | */ |
| 417 | if (variable_is_present(variable_name, &vendor_guid, |
| 418 | head)) { |
| 419 | dup_variable_bug(variable_name, &vendor_guid, |
| 420 | variable_name_size); |
| 421 | status = EFI_NOT_FOUND; |
| 422 | } else { |
| 423 | err = func(variable_name, vendor_guid, |
| 424 | variable_name_size, data, head); |
| 425 | if (err) |
| 426 | status = EFI_NOT_FOUND; |
| 427 | } |
| 428 | break; |
| 429 | case EFI_UNSUPPORTED: |
| 430 | err = -EOPNOTSUPP; |
| 431 | status = EFI_NOT_FOUND; |
| 432 | break; |
| 433 | case EFI_NOT_FOUND: |
| 434 | break; |
| 435 | case EFI_BUFFER_TOO_SMALL: |
| 436 | pr_warn("efivars: Variable name size exceeds maximum (%lu > 512)\n", |
| 437 | variable_name_size); |
| 438 | status = EFI_NOT_FOUND; |
| 439 | break; |
| 440 | default: |
| 441 | pr_warn("efivars: get_next_variable: status=%lx\n", status); |
| 442 | status = EFI_NOT_FOUND; |
| 443 | break; |
| 444 | } |
| 445 | |
| 446 | } while (status != EFI_NOT_FOUND); |
| 447 | |
| 448 | efivar_unlock(); |
| 449 | free: |
| 450 | kfree(variable_name); |
| 451 | |
| 452 | return err; |
| 453 | } |
| 454 | |
| 455 | /** |
| 456 | * efivar_entry_add - add entry to variable list |
| 457 | * @entry: entry to add to list |
| 458 | * @head: list head |
| 459 | * |
| 460 | * Returns 0 on success, or a kernel error code on failure. |
| 461 | */ |
| 462 | int efivar_entry_add(struct efivar_entry *entry, struct list_head *head) |
| 463 | { |
| 464 | int err; |
| 465 | |
| 466 | err = efivar_lock(); |
| 467 | if (err) |
| 468 | return err; |
| 469 | list_add(&entry->list, head); |
| 470 | efivar_unlock(); |
| 471 | |
| 472 | return 0; |
| 473 | } |
| 474 | |
| 475 | /** |
| 476 | * __efivar_entry_add - add entry to variable list |
| 477 | * @entry: entry to add to list |
| 478 | * @head: list head |
| 479 | */ |
| 480 | void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head) |
| 481 | { |
| 482 | list_add(&entry->list, head); |
| 483 | } |
| 484 | |
| 485 | /** |
| 486 | * efivar_entry_remove - remove entry from variable list |
| 487 | * @entry: entry to remove from list |
| 488 | * |
| 489 | * Returns 0 on success, or a kernel error code on failure. |
| 490 | */ |
| 491 | void efivar_entry_remove(struct efivar_entry *entry) |
| 492 | { |
| 493 | list_del(&entry->list); |
| 494 | } |
| 495 | |
| 496 | /* |
| 497 | * efivar_entry_list_del_unlock - remove entry from variable list |
| 498 | * @entry: entry to remove |
| 499 | * |
| 500 | * Remove @entry from the variable list and release the list lock. |
| 501 | * |
| 502 | * NOTE: slightly weird locking semantics here - we expect to be |
| 503 | * called with the efivars lock already held, and we release it before |
| 504 | * returning. This is because this function is usually called after |
| 505 | * set_variable() while the lock is still held. |
| 506 | */ |
| 507 | static void efivar_entry_list_del_unlock(struct efivar_entry *entry) |
| 508 | { |
| 509 | list_del(&entry->list); |
| 510 | efivar_unlock(); |
| 511 | } |
| 512 | |
| 513 | /** |
| 514 | * efivar_entry_delete - delete variable and remove entry from list |
| 515 | * @entry: entry containing variable to delete |
| 516 | * |
| 517 | * Delete the variable from the firmware and remove @entry from the |
| 518 | * variable list. It is the caller's responsibility to free @entry |
| 519 | * once we return. |
| 520 | * |
| 521 | * Returns 0 on success, -EINTR if we can't grab the semaphore, |
| 522 | * converted EFI status code if set_variable() fails. |
| 523 | */ |
| 524 | int efivar_entry_delete(struct efivar_entry *entry) |
| 525 | { |
| 526 | efi_status_t status; |
| 527 | int err; |
| 528 | |
| 529 | err = efivar_lock(); |
| 530 | if (err) |
| 531 | return err; |
| 532 | |
| 533 | status = efivar_set_variable_locked(entry->var.VariableName, |
| 534 | &entry->var.VendorGuid, |
| 535 | 0, 0, NULL, false); |
| 536 | if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { |
| 537 | efivar_unlock(); |
| 538 | return efi_status_to_err(status); |
| 539 | } |
| 540 | |
| 541 | efivar_entry_list_del_unlock(entry); |
| 542 | return 0; |
| 543 | } |
| 544 | |
| 545 | /** |
| 546 | * efivar_entry_size - obtain the size of a variable |
| 547 | * @entry: entry for this variable |
| 548 | * @size: location to store the variable's size |
| 549 | */ |
| 550 | int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
| 551 | { |
| 552 | efi_status_t status; |
| 553 | int err; |
| 554 | |
| 555 | *size = 0; |
| 556 | |
| 557 | err = efivar_lock(); |
| 558 | if (err) |
| 559 | return err; |
| 560 | |
| 561 | status = efivar_get_variable(entry->var.VariableName, |
| 562 | &entry->var.VendorGuid, NULL, size, NULL); |
| 563 | efivar_unlock(); |
| 564 | |
| 565 | if (status != EFI_BUFFER_TOO_SMALL) |
| 566 | return efi_status_to_err(status); |
| 567 | |
| 568 | return 0; |
| 569 | } |
| 570 | |
| 571 | /** |
| 572 | * __efivar_entry_get - call get_variable() |
| 573 | * @entry: read data for this variable |
| 574 | * @attributes: variable attributes |
| 575 | * @size: size of @data buffer |
| 576 | * @data: buffer to store variable data |
| 577 | * |
| 578 | * The caller MUST call efivar_entry_iter_begin() and |
| 579 | * efivar_entry_iter_end() before and after the invocation of this |
| 580 | * function, respectively. |
| 581 | */ |
| 582 | int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
| 583 | unsigned long *size, void *data) |
| 584 | { |
| 585 | efi_status_t status; |
| 586 | |
| 587 | status = efivar_get_variable(entry->var.VariableName, |
| 588 | &entry->var.VendorGuid, |
| 589 | attributes, size, data); |
| 590 | |
| 591 | return efi_status_to_err(status); |
| 592 | } |
| 593 | |
| 594 | /** |
| 595 | * efivar_entry_get - call get_variable() |
| 596 | * @entry: read data for this variable |
| 597 | * @attributes: variable attributes |
| 598 | * @size: size of @data buffer |
| 599 | * @data: buffer to store variable data |
| 600 | */ |
| 601 | int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
| 602 | unsigned long *size, void *data) |
| 603 | { |
| 604 | int err; |
| 605 | |
| 606 | err = efivar_lock(); |
| 607 | if (err) |
| 608 | return err; |
| 609 | err = __efivar_entry_get(entry, attributes, size, data); |
| 610 | efivar_unlock(); |
| 611 | |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | /** |
| 616 | * efivar_entry_set_get_size - call set_variable() and get new size (atomic) |
| 617 | * @entry: entry containing variable to set and get |
| 618 | * @attributes: attributes of variable to be written |
| 619 | * @size: size of data buffer |
| 620 | * @data: buffer containing data to write |
| 621 | * @set: did the set_variable() call succeed? |
| 622 | * |
| 623 | * This is a pretty special (complex) function. See efivarfs_file_write(). |
| 624 | * |
| 625 | * Atomically call set_variable() for @entry and if the call is |
| 626 | * successful, return the new size of the variable from get_variable() |
| 627 | * in @size. The success of set_variable() is indicated by @set. |
| 628 | * |
| 629 | * Returns 0 on success, -EINVAL if the variable data is invalid, |
| 630 | * -ENOSPC if the firmware does not have enough available space, or a |
| 631 | * converted EFI status code if either of set_variable() or |
| 632 | * get_variable() fail. |
| 633 | * |
| 634 | * If the EFI variable does not exist when calling set_variable() |
| 635 | * (EFI_NOT_FOUND), @entry is removed from the variable list. |
| 636 | */ |
| 637 | int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, |
| 638 | unsigned long *size, void *data, bool *set) |
| 639 | { |
| 640 | efi_char16_t *name = entry->var.VariableName; |
| 641 | efi_guid_t *vendor = &entry->var.VendorGuid; |
| 642 | efi_status_t status; |
| 643 | int err; |
| 644 | |
| 645 | *set = false; |
| 646 | |
| 647 | if (efivar_validate(*vendor, name, data, *size) == false) |
| 648 | return -EINVAL; |
| 649 | |
| 650 | /* |
| 651 | * The lock here protects the get_variable call, the conditional |
| 652 | * set_variable call, and removal of the variable from the efivars |
| 653 | * list (in the case of an authenticated delete). |
| 654 | */ |
| 655 | err = efivar_lock(); |
| 656 | if (err) |
| 657 | return err; |
| 658 | |
| 659 | status = efivar_set_variable_locked(name, vendor, attributes, *size, |
| 660 | data, false); |
| 661 | if (status != EFI_SUCCESS) { |
| 662 | err = efi_status_to_err(status); |
| 663 | goto out; |
| 664 | } |
| 665 | |
| 666 | *set = true; |
| 667 | |
| 668 | /* |
| 669 | * Writing to the variable may have caused a change in size (which |
| 670 | * could either be an append or an overwrite), or the variable to be |
| 671 | * deleted. Perform a GetVariable() so we can tell what actually |
| 672 | * happened. |
| 673 | */ |
| 674 | *size = 0; |
| 675 | status = efivar_get_variable(entry->var.VariableName, |
| 676 | &entry->var.VendorGuid, |
| 677 | NULL, size, NULL); |
| 678 | |
| 679 | if (status == EFI_NOT_FOUND) |
| 680 | efivar_entry_list_del_unlock(entry); |
| 681 | else |
| 682 | efivar_unlock(); |
| 683 | |
| 684 | if (status && status != EFI_BUFFER_TOO_SMALL) |
| 685 | return efi_status_to_err(status); |
| 686 | |
| 687 | return 0; |
| 688 | |
| 689 | out: |
| 690 | efivar_unlock(); |
| 691 | return err; |
| 692 | |
| 693 | } |
| 694 | |
| 695 | /** |
| 696 | * efivar_entry_iter - iterate over variable list |
| 697 | * @func: callback function |
| 698 | * @head: head of variable list |
| 699 | * @data: function-specific data to pass to callback |
| 700 | * |
| 701 | * Iterate over the list of EFI variables and call @func with every |
| 702 | * entry on the list. It is safe for @func to remove entries in the |
| 703 | * list via efivar_entry_delete() while iterating. |
| 704 | * |
| 705 | * Some notes for the callback function: |
| 706 | * - a non-zero return value indicates an error and terminates the loop |
| 707 | * - @func is called from atomic context |
| 708 | */ |
| 709 | int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), |
| 710 | struct list_head *head, void *data) |
| 711 | { |
| 712 | struct efivar_entry *entry, *n; |
| 713 | int err = 0; |
| 714 | |
| 715 | err = efivar_lock(); |
| 716 | if (err) |
| 717 | return err; |
| 718 | |
| 719 | list_for_each_entry_safe(entry, n, head, list) { |
| 720 | err = func(entry, data); |
| 721 | if (err) |
| 722 | break; |
| 723 | } |
| 724 | efivar_unlock(); |
| 725 | |
| 726 | return err; |
| 727 | } |