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