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 #include "../../firmware_attributes_class.h" 17 18 #define MAX_TYPES 4 19 #include <linux/nls.h> 20 21 struct wmi_sysman_priv wmi_priv = { 22 .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex), 23 }; 24 25 /* reset bios to defaults */ 26 static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"}; 27 static int reset_option = -1; 28 static struct class *fw_attr_class; 29 30 31 /** 32 * populate_string_buffer() - populates a string buffer 33 * @buffer: the start of the destination buffer 34 * @buffer_len: length of the destination buffer 35 * @str: the string to insert into buffer 36 */ 37 ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str) 38 { 39 u16 *length = (u16 *)buffer; 40 u16 *target = length + 1; 41 int ret; 42 43 ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, 44 target, buffer_len - sizeof(u16)); 45 if (ret < 0) { 46 dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n"); 47 return ret; 48 } 49 50 if ((ret * sizeof(u16)) > U16_MAX) { 51 dev_err(wmi_priv.class_dev, "Error string too long\n"); 52 return -ERANGE; 53 } 54 55 *length = ret * sizeof(u16); 56 return sizeof(u16) + *length; 57 } 58 59 /** 60 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication 61 * @str: the string to calculate based upon 62 * 63 */ 64 size_t calculate_string_buffer(const char *str) 65 { 66 /* u16 length field + one UTF16 char for each input char */ 67 return sizeof(u16) + strlen(str) * sizeof(u16); 68 } 69 70 /** 71 * calculate_security_buffer() - determines size of security buffer for authentication scheme 72 * @authentication: the authentication content 73 * 74 * Currently only supported type is Admin password 75 */ 76 size_t calculate_security_buffer(char *authentication) 77 { 78 if (strlen(authentication) > 0) { 79 return (sizeof(u32) * 2) + strlen(authentication) + 80 strlen(authentication) % 2; 81 } 82 return sizeof(u32) * 2; 83 } 84 85 /** 86 * populate_security_buffer() - builds a security buffer for authentication scheme 87 * @buffer: the buffer to populate 88 * @authentication: the authentication content 89 * 90 * Currently only supported type is PLAIN TEXT 91 */ 92 void populate_security_buffer(char *buffer, char *authentication) 93 { 94 char *auth = buffer + sizeof(u32) * 2; 95 u32 *sectype = (u32 *) buffer; 96 u32 *seclen = sectype + 1; 97 98 *sectype = strlen(authentication) > 0 ? 1 : 0; 99 *seclen = strlen(authentication); 100 101 /* plain text */ 102 if (strlen(authentication) > 0) 103 memcpy(auth, authentication, *seclen); 104 } 105 106 /** 107 * map_wmi_error() - map errors from WMI methods to kernel error codes 108 * @error_code: integer error code returned from Dell's firmware 109 */ 110 int map_wmi_error(int error_code) 111 { 112 switch (error_code) { 113 case 0: 114 /* success */ 115 return 0; 116 case 1: 117 /* failed */ 118 return -EIO; 119 case 2: 120 /* invalid parameter */ 121 return -EINVAL; 122 case 3: 123 /* access denied */ 124 return -EACCES; 125 case 4: 126 /* not supported */ 127 return -EOPNOTSUPP; 128 case 5: 129 /* memory error */ 130 return -ENOMEM; 131 case 6: 132 /* protocol error */ 133 return -EPROTO; 134 } 135 /* unspecified error */ 136 return -EIO; 137 } 138 139 /** 140 * reset_bios_show() - sysfs implementaton for read reset_bios 141 * @kobj: Kernel object for this attribute 142 * @attr: Kernel object attribute 143 * @buf: The buffer to display to userspace 144 */ 145 static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) 146 { 147 char *start = buf; 148 int i; 149 150 for (i = 0; i < MAX_TYPES; i++) { 151 if (i == reset_option) 152 buf += sprintf(buf, "[%s] ", reset_types[i]); 153 else 154 buf += sprintf(buf, "%s ", reset_types[i]); 155 } 156 buf += sprintf(buf, "\n"); 157 return buf-start; 158 } 159 160 /** 161 * reset_bios_store() - sysfs implementaton for write reset_bios 162 * @kobj: Kernel object for this attribute 163 * @attr: Kernel object attribute 164 * @buf: The buffer from userspace 165 * @count: the size of the buffer from userspace 166 */ 167 static ssize_t reset_bios_store(struct kobject *kobj, 168 struct kobj_attribute *attr, const char *buf, size_t count) 169 { 170 int type = sysfs_match_string(reset_types, buf); 171 int ret; 172 173 if (type < 0) 174 return type; 175 176 ret = set_bios_defaults(type); 177 pr_debug("reset all attributes request type %d: %d\n", type, ret); 178 if (!ret) { 179 reset_option = type; 180 ret = count; 181 } 182 183 return ret; 184 } 185 186 /** 187 * pending_reboot_show() - sysfs implementaton for read pending_reboot 188 * @kobj: Kernel object for this attribute 189 * @attr: Kernel object attribute 190 * @buf: The buffer to display to userspace 191 * 192 * Stores default value as 0 193 * When current_value is changed this attribute is set to 1 to notify reboot may be required 194 */ 195 static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr, 196 char *buf) 197 { 198 return sprintf(buf, "%d\n", wmi_priv.pending_changes); 199 } 200 201 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios); 202 static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot); 203 204 205 /** 206 * create_attributes_level_sysfs_files() - Creates reset_bios and 207 * pending_reboot attributes 208 */ 209 static int create_attributes_level_sysfs_files(void) 210 { 211 int ret; 212 213 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); 214 if (ret) 215 return ret; 216 217 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); 218 if (ret) 219 return ret; 220 221 return 0; 222 } 223 224 static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr, 225 char *buf) 226 { 227 struct kobj_attribute *kattr; 228 ssize_t ret = -EIO; 229 230 kattr = container_of(attr, struct kobj_attribute, attr); 231 if (kattr->show) 232 ret = kattr->show(kobj, kattr, buf); 233 return ret; 234 } 235 236 static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr, 237 const char *buf, size_t count) 238 { 239 struct kobj_attribute *kattr; 240 ssize_t ret = -EIO; 241 242 kattr = container_of(attr, struct kobj_attribute, attr); 243 if (kattr->store) 244 ret = kattr->store(kobj, kattr, buf, count); 245 return ret; 246 } 247 248 static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = { 249 .show = wmi_sysman_attr_show, 250 .store = wmi_sysman_attr_store, 251 }; 252 253 static void attr_name_release(struct kobject *kobj) 254 { 255 kfree(kobj); 256 } 257 258 static const struct kobj_type attr_name_ktype = { 259 .release = attr_name_release, 260 .sysfs_ops = &wmi_sysman_kobj_sysfs_ops, 261 }; 262 263 /** 264 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks 265 * @dest: Where to copy the string to 266 * @src: Where to copy the string from 267 */ 268 void strlcpy_attr(char *dest, char *src) 269 { 270 size_t len = strlen(src) + 1; 271 272 if (len > 1 && len <= MAX_BUFF) 273 strscpy(dest, src, len); 274 275 /*len can be zero because any property not-applicable to attribute can 276 * be empty so check only for too long buffers and log error 277 */ 278 if (len > MAX_BUFF) 279 pr_err("Source string returned from BIOS is out of bound!\n"); 280 } 281 282 /** 283 * get_wmiobj_pointer() - Get Content of WMI block for particular instance 284 * @instance_id: WMI instance ID 285 * @guid_string: WMI GUID (in str form) 286 * 287 * Fetches the content for WMI block (instance_id) under GUID (guid_string) 288 * Caller must kfree the return 289 */ 290 union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string) 291 { 292 struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL }; 293 acpi_status status; 294 295 status = wmi_query_block(guid_string, instance_id, &out); 296 297 return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL; 298 } 299 300 /** 301 * get_instance_count() - Compute total number of instances under guid_string 302 * @guid_string: WMI GUID (in string form) 303 */ 304 int get_instance_count(const char *guid_string) 305 { 306 union acpi_object *wmi_obj = NULL; 307 int i = 0; 308 309 do { 310 kfree(wmi_obj); 311 wmi_obj = get_wmiobj_pointer(i, guid_string); 312 i++; 313 } while (wmi_obj); 314 315 return (i-1); 316 } 317 318 /** 319 * alloc_attributes_data() - Allocate attributes data for a particular type 320 * @attr_type: Attribute type to allocate 321 */ 322 static int alloc_attributes_data(int attr_type) 323 { 324 int retval = 0; 325 326 switch (attr_type) { 327 case ENUM: 328 retval = alloc_enum_data(); 329 break; 330 case INT: 331 retval = alloc_int_data(); 332 break; 333 case STR: 334 retval = alloc_str_data(); 335 break; 336 case PO: 337 retval = alloc_po_data(); 338 break; 339 default: 340 break; 341 } 342 343 return retval; 344 } 345 346 /** 347 * destroy_attribute_objs() - Free a kset of kobjects 348 * @kset: The kset to destroy 349 * 350 * Fress kobjects created for each attribute_name under attribute type kset 351 */ 352 static void destroy_attribute_objs(struct kset *kset) 353 { 354 struct kobject *pos, *next; 355 356 list_for_each_entry_safe(pos, next, &kset->list, entry) { 357 kobject_put(pos); 358 } 359 } 360 361 /** 362 * release_attributes_data() - Clean-up all sysfs directories and files created 363 */ 364 static void release_attributes_data(void) 365 { 366 mutex_lock(&wmi_priv.mutex); 367 exit_enum_attributes(); 368 exit_int_attributes(); 369 exit_str_attributes(); 370 exit_po_attributes(); 371 if (wmi_priv.authentication_dir_kset) { 372 destroy_attribute_objs(wmi_priv.authentication_dir_kset); 373 kset_unregister(wmi_priv.authentication_dir_kset); 374 wmi_priv.authentication_dir_kset = NULL; 375 } 376 if (wmi_priv.main_dir_kset) { 377 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); 378 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); 379 destroy_attribute_objs(wmi_priv.main_dir_kset); 380 kset_unregister(wmi_priv.main_dir_kset); 381 wmi_priv.main_dir_kset = NULL; 382 } 383 mutex_unlock(&wmi_priv.mutex); 384 } 385 386 /** 387 * init_bios_attributes() - Initialize all attributes for a type 388 * @attr_type: The attribute type to initialize 389 * @guid: The WMI GUID associated with this type to initialize 390 * 391 * Initialiaze all 4 types of attributes enumeration, integer, string and password object. 392 * Populates each attrbute typ's respective properties under sysfs files 393 */ 394 static int init_bios_attributes(int attr_type, const char *guid) 395 { 396 struct kobject *attr_name_kobj; //individual attribute names 397 union acpi_object *obj = NULL; 398 union acpi_object *elements; 399 struct kset *tmp_set; 400 int min_elements; 401 402 /* instance_id needs to be reset for each type GUID 403 * also, instance IDs are unique within GUID but not across 404 */ 405 int instance_id = 0; 406 int retval = 0; 407 408 retval = alloc_attributes_data(attr_type); 409 if (retval) 410 return retval; 411 412 switch (attr_type) { 413 case ENUM: min_elements = 8; break; 414 case INT: min_elements = 9; break; 415 case STR: min_elements = 8; break; 416 case PO: min_elements = 4; break; 417 default: 418 pr_err("Error: Unknown attr_type: %d\n", attr_type); 419 return -EINVAL; 420 } 421 422 /* need to use specific instance_id and guid combination to get right data */ 423 obj = get_wmiobj_pointer(instance_id, guid); 424 if (!obj) 425 return -ENODEV; 426 427 mutex_lock(&wmi_priv.mutex); 428 while (obj) { 429 if (obj->type != ACPI_TYPE_PACKAGE) { 430 pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type); 431 retval = -EIO; 432 goto err_attr_init; 433 } 434 435 if (obj->package.count < min_elements) { 436 pr_err("Error: ACPI-package does not have enough elements: %d < %d\n", 437 obj->package.count, min_elements); 438 goto nextobj; 439 } 440 441 elements = obj->package.elements; 442 443 /* sanity checking */ 444 if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) { 445 pr_debug("incorrect element type\n"); 446 goto nextobj; 447 } 448 if (strlen(elements[ATTR_NAME].string.pointer) == 0) { 449 pr_debug("empty attribute found\n"); 450 goto nextobj; 451 } 452 if (attr_type == PO) 453 tmp_set = wmi_priv.authentication_dir_kset; 454 else 455 tmp_set = wmi_priv.main_dir_kset; 456 457 if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) { 458 pr_debug("duplicate attribute name found - %s\n", 459 elements[ATTR_NAME].string.pointer); 460 goto nextobj; 461 } 462 463 /* build attribute */ 464 attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL); 465 if (!attr_name_kobj) { 466 retval = -ENOMEM; 467 goto err_attr_init; 468 } 469 470 attr_name_kobj->kset = tmp_set; 471 472 retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s", 473 elements[ATTR_NAME].string.pointer); 474 if (retval) { 475 kobject_put(attr_name_kobj); 476 goto err_attr_init; 477 } 478 479 /* enumerate all of this attribute */ 480 switch (attr_type) { 481 case ENUM: 482 retval = populate_enum_data(elements, instance_id, attr_name_kobj, 483 obj->package.count); 484 break; 485 case INT: 486 retval = populate_int_data(elements, instance_id, attr_name_kobj); 487 break; 488 case STR: 489 retval = populate_str_data(elements, instance_id, attr_name_kobj); 490 break; 491 case PO: 492 retval = populate_po_data(elements, instance_id, attr_name_kobj); 493 break; 494 default: 495 break; 496 } 497 498 if (retval) { 499 pr_debug("failed to populate %s\n", 500 elements[ATTR_NAME].string.pointer); 501 goto err_attr_init; 502 } 503 504 nextobj: 505 kfree(obj); 506 instance_id++; 507 obj = get_wmiobj_pointer(instance_id, guid); 508 } 509 510 mutex_unlock(&wmi_priv.mutex); 511 return 0; 512 513 err_attr_init: 514 mutex_unlock(&wmi_priv.mutex); 515 kfree(obj); 516 return retval; 517 } 518 519 static int __init sysman_init(void) 520 { 521 int ret = 0; 522 523 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) && 524 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) { 525 pr_err("Unable to run on non-Dell system\n"); 526 return -ENODEV; 527 } 528 529 ret = init_bios_attr_set_interface(); 530 if (ret) 531 return ret; 532 533 ret = init_bios_attr_pass_interface(); 534 if (ret) 535 goto err_exit_bios_attr_set_interface; 536 537 if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) { 538 pr_debug("failed to find set or pass interface\n"); 539 ret = -ENODEV; 540 goto err_exit_bios_attr_pass_interface; 541 } 542 543 ret = fw_attributes_class_get(&fw_attr_class); 544 if (ret) 545 goto err_exit_bios_attr_pass_interface; 546 547 wmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0), 548 NULL, "%s", DRIVER_NAME); 549 if (IS_ERR(wmi_priv.class_dev)) { 550 ret = PTR_ERR(wmi_priv.class_dev); 551 goto err_unregister_class; 552 } 553 554 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL, 555 &wmi_priv.class_dev->kobj); 556 if (!wmi_priv.main_dir_kset) { 557 ret = -ENOMEM; 558 goto err_destroy_classdev; 559 } 560 561 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL, 562 &wmi_priv.class_dev->kobj); 563 if (!wmi_priv.authentication_dir_kset) { 564 ret = -ENOMEM; 565 goto err_release_attributes_data; 566 } 567 568 ret = create_attributes_level_sysfs_files(); 569 if (ret) { 570 pr_debug("could not create reset BIOS attribute\n"); 571 goto err_release_attributes_data; 572 } 573 574 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID); 575 if (ret) { 576 pr_debug("failed to populate enumeration type attributes\n"); 577 goto err_release_attributes_data; 578 } 579 580 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID); 581 if (ret) { 582 pr_debug("failed to populate integer type attributes\n"); 583 goto err_release_attributes_data; 584 } 585 586 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID); 587 if (ret) { 588 pr_debug("failed to populate string type attributes\n"); 589 goto err_release_attributes_data; 590 } 591 592 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID); 593 if (ret) { 594 pr_debug("failed to populate pass object type attributes\n"); 595 goto err_release_attributes_data; 596 } 597 598 return 0; 599 600 err_release_attributes_data: 601 release_attributes_data(); 602 603 err_destroy_classdev: 604 device_destroy(fw_attr_class, MKDEV(0, 0)); 605 606 err_unregister_class: 607 fw_attributes_class_put(); 608 609 err_exit_bios_attr_pass_interface: 610 exit_bios_attr_pass_interface(); 611 612 err_exit_bios_attr_set_interface: 613 exit_bios_attr_set_interface(); 614 615 return ret; 616 } 617 618 static void __exit sysman_exit(void) 619 { 620 release_attributes_data(); 621 device_destroy(fw_attr_class, MKDEV(0, 0)); 622 fw_attributes_class_put(); 623 exit_bios_attr_set_interface(); 624 exit_bios_attr_pass_interface(); 625 } 626 627 module_init(sysman_init); 628 module_exit(sysman_exit); 629 630 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>"); 631 MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>"); 632 MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>"); 633 MODULE_DESCRIPTION("Dell platform setting control interface"); 634 MODULE_LICENSE("GPL"); 635