1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Common methods for use with dell-wmi-sysman 4 * 5 * Copyright (c) 2020 Dell Inc. 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/fs.h> 11 #include <linux/dmi.h> 12 #include <linux/module.h> 13 #include <linux/kernel.h> 14 #include <linux/wmi.h> 15 #include "dell-wmi-sysman.h" 16 17 #define MAX_TYPES 4 18 #include <linux/nls.h> 19 20 static struct class firmware_attributes_class = { 21 .name = "firmware-attributes", 22 }; 23 24 struct wmi_sysman_priv wmi_priv = { 25 .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex), 26 }; 27 28 /* reset bios to defaults */ 29 static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"}; 30 static int reset_option = -1; 31 32 33 /** 34 * populate_string_buffer() - populates a string buffer 35 * @buffer: the start of the destination buffer 36 * @buffer_len: length of the destination buffer 37 * @str: the string to insert into buffer 38 */ 39 ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str) 40 { 41 u16 *length = (u16 *)buffer; 42 u16 *target = length + 1; 43 int ret; 44 45 ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, 46 target, buffer_len - sizeof(u16)); 47 if (ret < 0) { 48 dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n"); 49 return ret; 50 } 51 52 if ((ret * sizeof(u16)) > U16_MAX) { 53 dev_err(wmi_priv.class_dev, "Error string too long\n"); 54 return -ERANGE; 55 } 56 57 *length = ret * sizeof(u16); 58 return sizeof(u16) + *length; 59 } 60 61 /** 62 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication 63 * @str: the string to calculate based upon 64 * 65 */ 66 size_t calculate_string_buffer(const char *str) 67 { 68 /* u16 length field + one UTF16 char for each input char */ 69 return sizeof(u16) + strlen(str) * sizeof(u16); 70 } 71 72 /** 73 * calculate_security_buffer() - determines size of security buffer for authentication scheme 74 * @authentication: the authentication content 75 * 76 * Currently only supported type is Admin password 77 */ 78 size_t calculate_security_buffer(char *authentication) 79 { 80 if (strlen(authentication) > 0) { 81 return (sizeof(u32) * 2) + strlen(authentication) + 82 strlen(authentication) % 2; 83 } 84 return sizeof(u32) * 2; 85 } 86 87 /** 88 * populate_security_buffer() - builds a security buffer for authentication scheme 89 * @buffer: the buffer to populate 90 * @authentication: the authentication content 91 * 92 * Currently only supported type is PLAIN TEXT 93 */ 94 void populate_security_buffer(char *buffer, char *authentication) 95 { 96 char *auth = buffer + sizeof(u32) * 2; 97 u32 *sectype = (u32 *) buffer; 98 u32 *seclen = sectype + 1; 99 100 *sectype = strlen(authentication) > 0 ? 1 : 0; 101 *seclen = strlen(authentication); 102 103 /* plain text */ 104 if (strlen(authentication) > 0) 105 memcpy(auth, authentication, *seclen); 106 } 107 108 /** 109 * map_wmi_error() - map errors from WMI methods to kernel error codes 110 * @error_code: integer error code returned from Dell's firmware 111 */ 112 int map_wmi_error(int error_code) 113 { 114 switch (error_code) { 115 case 0: 116 /* success */ 117 return 0; 118 case 1: 119 /* failed */ 120 return -EIO; 121 case 2: 122 /* invalid parameter */ 123 return -EINVAL; 124 case 3: 125 /* access denied */ 126 return -EACCES; 127 case 4: 128 /* not supported */ 129 return -EOPNOTSUPP; 130 case 5: 131 /* memory error */ 132 return -ENOMEM; 133 case 6: 134 /* protocol error */ 135 return -EPROTO; 136 } 137 /* unspecified error */ 138 return -EIO; 139 } 140 141 /** 142 * reset_bios_show() - sysfs implementaton for read reset_bios 143 * @kobj: Kernel object for this attribute 144 * @attr: Kernel object attribute 145 * @buf: The buffer to display to userspace 146 */ 147 static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) 148 { 149 char *start = buf; 150 int i; 151 152 for (i = 0; i < MAX_TYPES; i++) { 153 if (i == reset_option) 154 buf += sprintf(buf, "[%s] ", reset_types[i]); 155 else 156 buf += sprintf(buf, "%s ", reset_types[i]); 157 } 158 buf += sprintf(buf, "\n"); 159 return buf-start; 160 } 161 162 /** 163 * reset_bios_store() - sysfs implementaton for write reset_bios 164 * @kobj: Kernel object for this attribute 165 * @attr: Kernel object attribute 166 * @buf: The buffer from userspace 167 * @count: the size of the buffer from userspace 168 */ 169 static ssize_t reset_bios_store(struct kobject *kobj, 170 struct kobj_attribute *attr, const char *buf, size_t count) 171 { 172 int type = sysfs_match_string(reset_types, buf); 173 int ret; 174 175 if (type < 0) 176 return type; 177 178 ret = set_bios_defaults(type); 179 pr_debug("reset all attributes request type %d: %d\n", type, ret); 180 if (!ret) { 181 reset_option = type; 182 ret = count; 183 } 184 185 return ret; 186 } 187 188 /** 189 * pending_reboot_show() - sysfs implementaton for read pending_reboot 190 * @kobj: Kernel object for this attribute 191 * @attr: Kernel object attribute 192 * @buf: The buffer to display to userspace 193 * 194 * Stores default value as 0 195 * When current_value is changed this attribute is set to 1 to notify reboot may be required 196 */ 197 static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr, 198 char *buf) 199 { 200 return sprintf(buf, "%d\n", wmi_priv.pending_changes); 201 } 202 203 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios); 204 static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot); 205 206 207 /** 208 * create_attributes_level_sysfs_files() - Creates reset_bios and 209 * pending_reboot attributes 210 */ 211 static int create_attributes_level_sysfs_files(void) 212 { 213 int ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); 214 215 if (ret) { 216 pr_debug("could not create reset_bios file\n"); 217 return ret; 218 } 219 220 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); 221 if (ret) { 222 pr_debug("could not create changing_pending_reboot file\n"); 223 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); 224 } 225 return ret; 226 } 227 228 static void release_reset_bios_data(void) 229 { 230 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); 231 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); 232 } 233 234 static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr, 235 char *buf) 236 { 237 struct kobj_attribute *kattr; 238 ssize_t ret = -EIO; 239 240 kattr = container_of(attr, struct kobj_attribute, attr); 241 if (kattr->show) 242 ret = kattr->show(kobj, kattr, buf); 243 return ret; 244 } 245 246 static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr, 247 const char *buf, size_t count) 248 { 249 struct kobj_attribute *kattr; 250 ssize_t ret = -EIO; 251 252 kattr = container_of(attr, struct kobj_attribute, attr); 253 if (kattr->store) 254 ret = kattr->store(kobj, kattr, buf, count); 255 return ret; 256 } 257 258 static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = { 259 .show = wmi_sysman_attr_show, 260 .store = wmi_sysman_attr_store, 261 }; 262 263 static void attr_name_release(struct kobject *kobj) 264 { 265 kfree(kobj); 266 } 267 268 static struct kobj_type attr_name_ktype = { 269 .release = attr_name_release, 270 .sysfs_ops = &wmi_sysman_kobj_sysfs_ops, 271 }; 272 273 /** 274 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks 275 * @dest: Where to copy the string to 276 * @src: Where to copy the string from 277 */ 278 void strlcpy_attr(char *dest, char *src) 279 { 280 size_t len = strlen(src) + 1; 281 282 if (len > 1 && len <= MAX_BUFF) 283 strlcpy(dest, src, len); 284 285 /*len can be zero because any property not-applicable to attribute can 286 * be empty so check only for too long buffers and log error 287 */ 288 if (len > MAX_BUFF) 289 pr_err("Source string returned from BIOS is out of bound!\n"); 290 } 291 292 /** 293 * get_wmiobj_pointer() - Get Content of WMI block for particular instance 294 * @instance_id: WMI instance ID 295 * @guid_string: WMI GUID (in str form) 296 * 297 * Fetches the content for WMI block (instance_id) under GUID (guid_string) 298 * Caller must kfree the return 299 */ 300 union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string) 301 { 302 struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL }; 303 acpi_status status; 304 305 status = wmi_query_block(guid_string, instance_id, &out); 306 307 return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL; 308 } 309 310 /** 311 * get_instance_count() - Compute total number of instances under guid_string 312 * @guid_string: WMI GUID (in string form) 313 */ 314 int get_instance_count(const char *guid_string) 315 { 316 union acpi_object *wmi_obj = NULL; 317 int i = 0; 318 319 do { 320 kfree(wmi_obj); 321 wmi_obj = get_wmiobj_pointer(i, guid_string); 322 i++; 323 } while (wmi_obj); 324 325 return (i-1); 326 } 327 328 /** 329 * alloc_attributes_data() - Allocate attributes data for a particular type 330 * @attr_type: Attribute type to allocate 331 */ 332 static int alloc_attributes_data(int attr_type) 333 { 334 int retval = 0; 335 336 switch (attr_type) { 337 case ENUM: 338 retval = alloc_enum_data(); 339 break; 340 case INT: 341 retval = alloc_int_data(); 342 break; 343 case STR: 344 retval = alloc_str_data(); 345 break; 346 case PO: 347 retval = alloc_po_data(); 348 break; 349 default: 350 break; 351 } 352 353 return retval; 354 } 355 356 /** 357 * destroy_attribute_objs() - Free a kset of kobjects 358 * @kset: The kset to destroy 359 * 360 * Fress kobjects created for each attribute_name under attribute type kset 361 */ 362 static void destroy_attribute_objs(struct kset *kset) 363 { 364 struct kobject *pos, *next; 365 366 list_for_each_entry_safe(pos, next, &kset->list, entry) { 367 kobject_put(pos); 368 } 369 } 370 371 /** 372 * release_attributes_data() - Clean-up all sysfs directories and files created 373 */ 374 static void release_attributes_data(void) 375 { 376 release_reset_bios_data(); 377 378 mutex_lock(&wmi_priv.mutex); 379 exit_enum_attributes(); 380 exit_int_attributes(); 381 exit_str_attributes(); 382 exit_po_attributes(); 383 if (wmi_priv.authentication_dir_kset) { 384 destroy_attribute_objs(wmi_priv.authentication_dir_kset); 385 kset_unregister(wmi_priv.authentication_dir_kset); 386 wmi_priv.authentication_dir_kset = NULL; 387 } 388 if (wmi_priv.main_dir_kset) { 389 destroy_attribute_objs(wmi_priv.main_dir_kset); 390 kset_unregister(wmi_priv.main_dir_kset); 391 } 392 mutex_unlock(&wmi_priv.mutex); 393 394 } 395 396 /** 397 * init_bios_attributes() - Initialize all attributes for a type 398 * @attr_type: The attribute type to initialize 399 * @guid: The WMI GUID associated with this type to initialize 400 * 401 * Initialiaze all 4 types of attributes enumeration, integer, string and password object. 402 * Populates each attrbute typ's respective properties under sysfs files 403 */ 404 static int init_bios_attributes(int attr_type, const char *guid) 405 { 406 struct kobject *attr_name_kobj; //individual attribute names 407 union acpi_object *obj = NULL; 408 union acpi_object *elements; 409 struct kset *tmp_set; 410 411 /* instance_id needs to be reset for each type GUID 412 * also, instance IDs are unique within GUID but not across 413 */ 414 int instance_id = 0; 415 int retval = 0; 416 417 retval = alloc_attributes_data(attr_type); 418 if (retval) 419 return retval; 420 /* need to use specific instance_id and guid combination to get right data */ 421 obj = get_wmiobj_pointer(instance_id, guid); 422 if (!obj || obj->type != ACPI_TYPE_PACKAGE) 423 return -ENODEV; 424 elements = obj->package.elements; 425 426 mutex_lock(&wmi_priv.mutex); 427 while (elements) { 428 /* sanity checking */ 429 if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) { 430 pr_debug("incorrect element type\n"); 431 goto nextobj; 432 } 433 if (strlen(elements[ATTR_NAME].string.pointer) == 0) { 434 pr_debug("empty attribute found\n"); 435 goto nextobj; 436 } 437 if (attr_type == PO) 438 tmp_set = wmi_priv.authentication_dir_kset; 439 else 440 tmp_set = wmi_priv.main_dir_kset; 441 442 if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) { 443 pr_debug("duplicate attribute name found - %s\n", 444 elements[ATTR_NAME].string.pointer); 445 goto nextobj; 446 } 447 448 /* build attribute */ 449 attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL); 450 if (!attr_name_kobj) { 451 retval = -ENOMEM; 452 goto err_attr_init; 453 } 454 455 attr_name_kobj->kset = tmp_set; 456 457 retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s", 458 elements[ATTR_NAME].string.pointer); 459 if (retval) { 460 kobject_put(attr_name_kobj); 461 goto err_attr_init; 462 } 463 464 /* enumerate all of this attribute */ 465 switch (attr_type) { 466 case ENUM: 467 retval = populate_enum_data(elements, instance_id, attr_name_kobj); 468 break; 469 case INT: 470 retval = populate_int_data(elements, instance_id, attr_name_kobj); 471 break; 472 case STR: 473 retval = populate_str_data(elements, instance_id, attr_name_kobj); 474 break; 475 case PO: 476 retval = populate_po_data(elements, instance_id, attr_name_kobj); 477 break; 478 default: 479 break; 480 } 481 482 if (retval) { 483 pr_debug("failed to populate %s\n", 484 elements[ATTR_NAME].string.pointer); 485 goto err_attr_init; 486 } 487 488 nextobj: 489 kfree(obj); 490 instance_id++; 491 obj = get_wmiobj_pointer(instance_id, guid); 492 elements = obj ? obj->package.elements : NULL; 493 } 494 495 mutex_unlock(&wmi_priv.mutex); 496 return 0; 497 498 err_attr_init: 499 mutex_unlock(&wmi_priv.mutex); 500 release_attributes_data(); 501 kfree(obj); 502 return retval; 503 } 504 505 static int __init sysman_init(void) 506 { 507 int ret = 0; 508 509 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) && 510 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) { 511 pr_err("Unable to run on non-Dell system\n"); 512 return -ENODEV; 513 } 514 515 ret = init_bios_attr_set_interface(); 516 if (ret || !wmi_priv.bios_attr_wdev) { 517 pr_debug("failed to initialize set interface\n"); 518 goto fail_set_interface; 519 } 520 521 ret = init_bios_attr_pass_interface(); 522 if (ret || !wmi_priv.password_attr_wdev) { 523 pr_debug("failed to initialize pass interface\n"); 524 goto fail_pass_interface; 525 } 526 527 ret = class_register(&firmware_attributes_class); 528 if (ret) 529 goto fail_class; 530 531 wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0), 532 NULL, "%s", DRIVER_NAME); 533 if (IS_ERR(wmi_priv.class_dev)) { 534 ret = PTR_ERR(wmi_priv.class_dev); 535 goto fail_classdev; 536 } 537 538 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL, 539 &wmi_priv.class_dev->kobj); 540 if (!wmi_priv.main_dir_kset) { 541 ret = -ENOMEM; 542 goto fail_main_kset; 543 } 544 545 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL, 546 &wmi_priv.class_dev->kobj); 547 if (!wmi_priv.authentication_dir_kset) { 548 ret = -ENOMEM; 549 goto fail_authentication_kset; 550 } 551 552 ret = create_attributes_level_sysfs_files(); 553 if (ret) { 554 pr_debug("could not create reset BIOS attribute\n"); 555 goto fail_reset_bios; 556 } 557 558 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID); 559 if (ret) { 560 pr_debug("failed to populate enumeration type attributes\n"); 561 goto fail_create_group; 562 } 563 564 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID); 565 if (ret) { 566 pr_debug("failed to populate integer type attributes\n"); 567 goto fail_create_group; 568 } 569 570 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID); 571 if (ret) { 572 pr_debug("failed to populate string type attributes\n"); 573 goto fail_create_group; 574 } 575 576 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID); 577 if (ret) { 578 pr_debug("failed to populate pass object type attributes\n"); 579 goto fail_create_group; 580 } 581 582 return 0; 583 584 fail_create_group: 585 release_attributes_data(); 586 587 fail_reset_bios: 588 if (wmi_priv.authentication_dir_kset) { 589 kset_unregister(wmi_priv.authentication_dir_kset); 590 wmi_priv.authentication_dir_kset = NULL; 591 } 592 593 fail_authentication_kset: 594 if (wmi_priv.main_dir_kset) { 595 kset_unregister(wmi_priv.main_dir_kset); 596 wmi_priv.main_dir_kset = NULL; 597 } 598 599 fail_main_kset: 600 device_destroy(&firmware_attributes_class, MKDEV(0, 0)); 601 602 fail_classdev: 603 class_unregister(&firmware_attributes_class); 604 605 fail_class: 606 exit_bios_attr_pass_interface(); 607 608 fail_pass_interface: 609 exit_bios_attr_set_interface(); 610 611 fail_set_interface: 612 return ret; 613 } 614 615 static void __exit sysman_exit(void) 616 { 617 release_attributes_data(); 618 device_destroy(&firmware_attributes_class, MKDEV(0, 0)); 619 class_unregister(&firmware_attributes_class); 620 exit_bios_attr_set_interface(); 621 exit_bios_attr_pass_interface(); 622 } 623 624 module_init(sysman_init); 625 module_exit(sysman_exit); 626 627 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>"); 628 MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>"); 629 MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>"); 630 MODULE_DESCRIPTION("Dell platform setting control interface"); 631 MODULE_LICENSE("GPL"); 632