efivars: Improve variable validation
[linux-2.6.git] / drivers / firmware / efivars.c
1 /*
2  * EFI Variables - efivars.c
3  *
4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6  *
7  * This code takes all variables accessible from EFI runtime and
8  *  exports them via sysfs
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to the Free Software
22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23  *
24  * Changelog:
25  *
26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27  *   remove check for efi_enabled in exit
28  *   add MODULE_VERSION
29  *
30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
31  *   minor bug fixes
32  *
33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34  *   converted driver to export variable information via sysfs
35  *   and moved to drivers/firmware directory
36  *   bumped revision number to v0.07 to reflect conversion & move
37  *
38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39  *   fix locking per Peter Chubb's findings
40  *
41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
43  *
44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45  *   use list_for_each_safe when deleting vars.
46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
47  *   v0.04 release to linux-ia64@linuxia64.org
48  *
49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
51  *   efi.c own the /proc/efi directory.
52  *   v0.03 release to linux-ia64@linuxia64.org
53  *
54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55  *   At the request of Stephane, moved ownership of /proc/efi
56  *   to efi.c, and now efivars lives under /proc/efi/vars.
57  *
58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59  *   Feedback received from Stephane Eranian incorporated.
60  *   efivar_write() checks copy_from_user() return value.
61  *   efivar_read/write() returns proper errno.
62  *   v0.02 release to linux-ia64@linuxia64.org
63  *
64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65  *   v0.01 release to linux-ia64@linuxia64.org
66  */
67
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
72 #include <linux/mm.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81 #include <linux/pstore.h>
82
83 #include <asm/uaccess.h>
84
85 #define EFIVARS_VERSION "0.08"
86 #define EFIVARS_DATE "2004-May-17"
87
88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
90 MODULE_LICENSE("GPL");
91 MODULE_VERSION(EFIVARS_VERSION);
92
93 #define DUMP_NAME_LEN 52
94
95 /*
96  * The maximum size of VariableName + Data = 1024
97  * Therefore, it's reasonable to save that much
98  * space in each part of the structure,
99  * and we use a page for reading/writing.
100  */
101
102 struct efi_variable {
103         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
104         efi_guid_t    VendorGuid;
105         unsigned long DataSize;
106         __u8          Data[1024];
107         efi_status_t  Status;
108         __u32         Attributes;
109 } __attribute__((packed));
110
111
112 struct efivar_entry {
113         struct efivars *efivars;
114         struct efi_variable var;
115         struct list_head list;
116         struct kobject kobj;
117 };
118
119 struct efivar_attribute {
120         struct attribute attr;
121         ssize_t (*show) (struct efivar_entry *entry, char *buf);
122         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
123 };
124
125 #define PSTORE_EFI_ATTRIBUTES \
126         (EFI_VARIABLE_NON_VOLATILE | \
127          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
128          EFI_VARIABLE_RUNTIME_ACCESS)
129
130 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
131 struct efivar_attribute efivar_attr_##_name = { \
132         .attr = {.name = __stringify(_name), .mode = _mode}, \
133         .show = _show, \
134         .store = _store, \
135 };
136
137 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
138 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
139
140 /*
141  * Prototype for sysfs creation function
142  */
143 static int
144 efivar_create_sysfs_entry(struct efivars *efivars,
145                           unsigned long variable_name_size,
146                           efi_char16_t *variable_name,
147                           efi_guid_t *vendor_guid);
148
149 /* Return the number of unicode characters in data */
150 static unsigned long
151 utf16_strnlen(efi_char16_t *s, size_t maxlength)
152 {
153         unsigned long length = 0;
154
155         while (*s++ != 0 && length < maxlength)
156                 length++;
157         return length;
158 }
159
160 static inline unsigned long
161 utf16_strlen(efi_char16_t *s)
162 {
163         return utf16_strnlen(s, ~0UL);
164 }
165
166 /*
167  * Return the number of bytes is the length of this string
168  * Note: this is NOT the same as the number of unicode characters
169  */
170 static inline unsigned long
171 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
172 {
173         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
174 }
175
176 static inline int
177 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
178 {
179         while (1) {
180                 if (len == 0)
181                         return 0;
182                 if (*a < *b)
183                         return -1;
184                 if (*a > *b)
185                         return 1;
186                 if (*a == 0) /* implies *b == 0 */
187                         return 0;
188                 a++;
189                 b++;
190                 len--;
191         }
192 }
193
194 static bool
195 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
196                      unsigned long len)
197 {
198         struct efi_generic_dev_path *node;
199         int offset = 0;
200
201         node = (struct efi_generic_dev_path *)buffer;
202
203         if (len < sizeof(*node))
204                 return false;
205
206         while (offset <= len - sizeof(*node) &&
207                node->length >= sizeof(*node) &&
208                 node->length <= len - offset) {
209                 offset += node->length;
210
211                 if ((node->type == EFI_DEV_END_PATH ||
212                      node->type == EFI_DEV_END_PATH2) &&
213                     node->sub_type == EFI_DEV_END_ENTIRE)
214                         return true;
215
216                 node = (struct efi_generic_dev_path *)(buffer + offset);
217         }
218
219         /*
220          * If we're here then either node->length pointed past the end
221          * of the buffer or we reached the end of the buffer without
222          * finding a device path end node.
223          */
224         return false;
225 }
226
227 static bool
228 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
229                     unsigned long len)
230 {
231         /* An array of 16-bit integers */
232         if ((len % 2) != 0)
233                 return false;
234
235         return true;
236 }
237
238 static bool
239 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
240                      unsigned long len)
241 {
242         u16 filepathlength;
243         int i, desclength = 0, namelen;
244
245         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
246
247         /* Either "Boot" or "Driver" followed by four digits of hex */
248         for (i = match; i < match+4; i++) {
249                 if (var->VariableName[i] > 127 ||
250                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
251                         return true;
252         }
253
254         /* Reject it if there's 4 digits of hex and then further content */
255         if (namelen > match + 4)
256                 return false;
257
258         /* A valid entry must be at least 8 bytes */
259         if (len < 8)
260                 return false;
261
262         filepathlength = buffer[4] | buffer[5] << 8;
263
264         /*
265          * There's no stored length for the description, so it has to be
266          * found by hand
267          */
268         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
269
270         /* Each boot entry must have a descriptor */
271         if (!desclength)
272                 return false;
273
274         /*
275          * If the sum of the length of the description, the claimed filepath
276          * length and the original header are greater than the length of the
277          * variable, it's malformed
278          */
279         if ((desclength + filepathlength + 6) > len)
280                 return false;
281
282         /*
283          * And, finally, check the filepath
284          */
285         return validate_device_path(var, match, buffer + desclength + 6,
286                                     filepathlength);
287 }
288
289 static bool
290 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
291                 unsigned long len)
292 {
293         /* A single 16-bit integer */
294         if (len != 2)
295                 return false;
296
297         return true;
298 }
299
300 static bool
301 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
302                       unsigned long len)
303 {
304         int i;
305
306         for (i = 0; i < len; i++) {
307                 if (buffer[i] > 127)
308                         return false;
309
310                 if (buffer[i] == 0)
311                         return true;
312         }
313
314         return false;
315 }
316
317 struct variable_validate {
318         char *name;
319         bool (*validate)(struct efi_variable *var, int match, u8 *data,
320                          unsigned long len);
321 };
322
323 static const struct variable_validate variable_validate[] = {
324         { "BootNext", validate_uint16 },
325         { "BootOrder", validate_boot_order },
326         { "DriverOrder", validate_boot_order },
327         { "Boot*", validate_load_option },
328         { "Driver*", validate_load_option },
329         { "ConIn", validate_device_path },
330         { "ConInDev", validate_device_path },
331         { "ConOut", validate_device_path },
332         { "ConOutDev", validate_device_path },
333         { "ErrOut", validate_device_path },
334         { "ErrOutDev", validate_device_path },
335         { "Timeout", validate_uint16 },
336         { "Lang", validate_ascii_string },
337         { "PlatformLang", validate_ascii_string },
338         { "", NULL },
339 };
340
341 static bool
342 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
343 {
344         int i;
345         u16 *unicode_name = var->VariableName;
346
347         for (i = 0; variable_validate[i].validate != NULL; i++) {
348                 const char *name = variable_validate[i].name;
349                 int match;
350
351                 for (match = 0; ; match++) {
352                         char c = name[match];
353                         u16 u = unicode_name[match];
354
355                         /* All special variables are plain ascii */
356                         if (u > 127)
357                                 return true;
358
359                         /* Wildcard in the matching name means we've matched */
360                         if (c == '*')
361                                 return variable_validate[i].validate(var,
362                                                              match, data, len);
363
364                         /* Case sensitive match */
365                         if (c != u)
366                                 break;
367
368                         /* Reached the end of the string while matching */
369                         if (!c)
370                                 return variable_validate[i].validate(var,
371                                                              match, data, len);
372                 }
373         }
374
375         return true;
376 }
377
378 static efi_status_t
379 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
380 {
381         efi_status_t status;
382
383         var->DataSize = 1024;
384         status = efivars->ops->get_variable(var->VariableName,
385                                             &var->VendorGuid,
386                                             &var->Attributes,
387                                             &var->DataSize,
388                                             var->Data);
389         return status;
390 }
391
392 static efi_status_t
393 get_var_data(struct efivars *efivars, struct efi_variable *var)
394 {
395         efi_status_t status;
396
397         spin_lock(&efivars->lock);
398         status = get_var_data_locked(efivars, var);
399         spin_unlock(&efivars->lock);
400
401         if (status != EFI_SUCCESS) {
402                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
403                         status);
404         }
405         return status;
406 }
407
408 static ssize_t
409 efivar_guid_read(struct efivar_entry *entry, char *buf)
410 {
411         struct efi_variable *var = &entry->var;
412         char *str = buf;
413
414         if (!entry || !buf)
415                 return 0;
416
417         efi_guid_unparse(&var->VendorGuid, str);
418         str += strlen(str);
419         str += sprintf(str, "\n");
420
421         return str - buf;
422 }
423
424 static ssize_t
425 efivar_attr_read(struct efivar_entry *entry, char *buf)
426 {
427         struct efi_variable *var = &entry->var;
428         char *str = buf;
429         efi_status_t status;
430
431         if (!entry || !buf)
432                 return -EINVAL;
433
434         status = get_var_data(entry->efivars, var);
435         if (status != EFI_SUCCESS)
436                 return -EIO;
437
438         if (var->Attributes & 0x1)
439                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
440         if (var->Attributes & 0x2)
441                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
442         if (var->Attributes & 0x4)
443                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
444         return str - buf;
445 }
446
447 static ssize_t
448 efivar_size_read(struct efivar_entry *entry, char *buf)
449 {
450         struct efi_variable *var = &entry->var;
451         char *str = buf;
452         efi_status_t status;
453
454         if (!entry || !buf)
455                 return -EINVAL;
456
457         status = get_var_data(entry->efivars, var);
458         if (status != EFI_SUCCESS)
459                 return -EIO;
460
461         str += sprintf(str, "0x%lx\n", var->DataSize);
462         return str - buf;
463 }
464
465 static ssize_t
466 efivar_data_read(struct efivar_entry *entry, char *buf)
467 {
468         struct efi_variable *var = &entry->var;
469         efi_status_t status;
470
471         if (!entry || !buf)
472                 return -EINVAL;
473
474         status = get_var_data(entry->efivars, var);
475         if (status != EFI_SUCCESS)
476                 return -EIO;
477
478         memcpy(buf, var->Data, var->DataSize);
479         return var->DataSize;
480 }
481 /*
482  * We allow each variable to be edited via rewriting the
483  * entire efi variable structure.
484  */
485 static ssize_t
486 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
487 {
488         struct efi_variable *new_var, *var = &entry->var;
489         struct efivars *efivars = entry->efivars;
490         efi_status_t status = EFI_NOT_FOUND;
491
492         if (count != sizeof(struct efi_variable))
493                 return -EINVAL;
494
495         new_var = (struct efi_variable *)buf;
496         /*
497          * If only updating the variable data, then the name
498          * and guid should remain the same
499          */
500         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
501                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
502                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
503                 return -EINVAL;
504         }
505
506         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
507                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
508                 return -EINVAL;
509         }
510
511         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
512             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
513                 printk(KERN_ERR "efivars: Malformed variable content\n");
514                 return -EINVAL;
515         }
516
517         spin_lock(&efivars->lock);
518         status = efivars->ops->set_variable(new_var->VariableName,
519                                             &new_var->VendorGuid,
520                                             new_var->Attributes,
521                                             new_var->DataSize,
522                                             new_var->Data);
523
524         spin_unlock(&efivars->lock);
525
526         if (status != EFI_SUCCESS) {
527                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
528                         status);
529                 return -EIO;
530         }
531
532         memcpy(&entry->var, new_var, count);
533         return count;
534 }
535
536 static ssize_t
537 efivar_show_raw(struct efivar_entry *entry, char *buf)
538 {
539         struct efi_variable *var = &entry->var;
540         efi_status_t status;
541
542         if (!entry || !buf)
543                 return 0;
544
545         status = get_var_data(entry->efivars, var);
546         if (status != EFI_SUCCESS)
547                 return -EIO;
548
549         memcpy(buf, var, sizeof(*var));
550         return sizeof(*var);
551 }
552
553 /*
554  * Generic read/write functions that call the specific functions of
555  * the attributes...
556  */
557 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
558                                 char *buf)
559 {
560         struct efivar_entry *var = to_efivar_entry(kobj);
561         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
562         ssize_t ret = -EIO;
563
564         if (!capable(CAP_SYS_ADMIN))
565                 return -EACCES;
566
567         if (efivar_attr->show) {
568                 ret = efivar_attr->show(var, buf);
569         }
570         return ret;
571 }
572
573 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
574                                 const char *buf, size_t count)
575 {
576         struct efivar_entry *var = to_efivar_entry(kobj);
577         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
578         ssize_t ret = -EIO;
579
580         if (!capable(CAP_SYS_ADMIN))
581                 return -EACCES;
582
583         if (efivar_attr->store)
584                 ret = efivar_attr->store(var, buf, count);
585
586         return ret;
587 }
588
589 static const struct sysfs_ops efivar_attr_ops = {
590         .show = efivar_attr_show,
591         .store = efivar_attr_store,
592 };
593
594 static void efivar_release(struct kobject *kobj)
595 {
596         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
597         kfree(var);
598 }
599
600 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
601 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
602 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
603 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
604 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
605
606 static struct attribute *def_attrs[] = {
607         &efivar_attr_guid.attr,
608         &efivar_attr_size.attr,
609         &efivar_attr_attributes.attr,
610         &efivar_attr_data.attr,
611         &efivar_attr_raw_var.attr,
612         NULL,
613 };
614
615 static struct kobj_type efivar_ktype = {
616         .release = efivar_release,
617         .sysfs_ops = &efivar_attr_ops,
618         .default_attrs = def_attrs,
619 };
620
621 static struct pstore_info efi_pstore_info;
622
623 static inline void
624 efivar_unregister(struct efivar_entry *var)
625 {
626         kobject_put(&var->kobj);
627 }
628
629 #ifdef CONFIG_PSTORE
630
631 static int efi_pstore_open(struct pstore_info *psi)
632 {
633         struct efivars *efivars = psi->data;
634
635         spin_lock(&efivars->lock);
636         efivars->walk_entry = list_first_entry(&efivars->list,
637                                                struct efivar_entry, list);
638         return 0;
639 }
640
641 static int efi_pstore_close(struct pstore_info *psi)
642 {
643         struct efivars *efivars = psi->data;
644
645         spin_unlock(&efivars->lock);
646         return 0;
647 }
648
649 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
650                                struct timespec *timespec,
651                                char **buf, struct pstore_info *psi)
652 {
653         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
654         struct efivars *efivars = psi->data;
655         char name[DUMP_NAME_LEN];
656         int i;
657         unsigned int part, size;
658         unsigned long time;
659
660         while (&efivars->walk_entry->list != &efivars->list) {
661                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
662                                  vendor)) {
663                         for (i = 0; i < DUMP_NAME_LEN; i++) {
664                                 name[i] = efivars->walk_entry->var.VariableName[i];
665                         }
666                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
667                                 *id = part;
668                                 timespec->tv_sec = time;
669                                 timespec->tv_nsec = 0;
670                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
671                                 size = efivars->walk_entry->var.DataSize;
672                                 *buf = kmalloc(size, GFP_KERNEL);
673                                 if (*buf == NULL)
674                                         return -ENOMEM;
675                                 memcpy(*buf, efivars->walk_entry->var.Data,
676                                        size);
677                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
678                                                    struct efivar_entry, list);
679                                 return size;
680                         }
681                 }
682                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
683                                                  struct efivar_entry, list);
684         }
685         return 0;
686 }
687
688 static int efi_pstore_write(enum pstore_type_id type,
689                 enum kmsg_dump_reason reason, u64 *id,
690                 unsigned int part, size_t size, struct pstore_info *psi)
691 {
692         char name[DUMP_NAME_LEN];
693         char stub_name[DUMP_NAME_LEN];
694         efi_char16_t efi_name[DUMP_NAME_LEN];
695         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
696         struct efivars *efivars = psi->data;
697         struct efivar_entry *entry, *found = NULL;
698         int i, ret = 0;
699
700         sprintf(stub_name, "dump-type%u-%u-", type, part);
701         sprintf(name, "%s%lu", stub_name, get_seconds());
702
703         spin_lock(&efivars->lock);
704
705         for (i = 0; i < DUMP_NAME_LEN; i++)
706                 efi_name[i] = stub_name[i];
707
708         /*
709          * Clean up any entries with the same name
710          */
711
712         list_for_each_entry(entry, &efivars->list, list) {
713                 get_var_data_locked(efivars, &entry->var);
714
715                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
716                         continue;
717                 if (utf16_strncmp(entry->var.VariableName, efi_name,
718                                   utf16_strlen(efi_name)))
719                         continue;
720                 /* Needs to be a prefix */
721                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
722                         continue;
723
724                 /* found */
725                 found = entry;
726                 efivars->ops->set_variable(entry->var.VariableName,
727                                            &entry->var.VendorGuid,
728                                            PSTORE_EFI_ATTRIBUTES,
729                                            0, NULL);
730         }
731
732         if (found)
733                 list_del(&found->list);
734
735         for (i = 0; i < DUMP_NAME_LEN; i++)
736                 efi_name[i] = name[i];
737
738         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
739                                    size, psi->buf);
740
741         spin_unlock(&efivars->lock);
742
743         if (found)
744                 efivar_unregister(found);
745
746         if (size)
747                 ret = efivar_create_sysfs_entry(efivars,
748                                           utf16_strsize(efi_name,
749                                                         DUMP_NAME_LEN * 2),
750                                           efi_name, &vendor);
751
752         *id = part;
753         return ret;
754 };
755
756 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
757                             struct pstore_info *psi)
758 {
759         efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
760
761         return 0;
762 }
763 #else
764 static int efi_pstore_open(struct pstore_info *psi)
765 {
766         return 0;
767 }
768
769 static int efi_pstore_close(struct pstore_info *psi)
770 {
771         return 0;
772 }
773
774 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
775                                struct timespec *timespec,
776                                char **buf, struct pstore_info *psi)
777 {
778         return -1;
779 }
780
781 static int efi_pstore_write(enum pstore_type_id type,
782                 enum kmsg_dump_reason reason, u64 *id,
783                 unsigned int part, size_t size, struct pstore_info *psi)
784 {
785         return 0;
786 }
787
788 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
789                             struct pstore_info *psi)
790 {
791         return 0;
792 }
793 #endif
794
795 static struct pstore_info efi_pstore_info = {
796         .owner          = THIS_MODULE,
797         .name           = "efi",
798         .open           = efi_pstore_open,
799         .close          = efi_pstore_close,
800         .read           = efi_pstore_read,
801         .write          = efi_pstore_write,
802         .erase          = efi_pstore_erase,
803 };
804
805 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
806                              struct bin_attribute *bin_attr,
807                              char *buf, loff_t pos, size_t count)
808 {
809         struct efi_variable *new_var = (struct efi_variable *)buf;
810         struct efivars *efivars = bin_attr->private;
811         struct efivar_entry *search_efivar, *n;
812         unsigned long strsize1, strsize2;
813         efi_status_t status = EFI_NOT_FOUND;
814         int found = 0;
815
816         if (!capable(CAP_SYS_ADMIN))
817                 return -EACCES;
818
819         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
820             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
821                 printk(KERN_ERR "efivars: Malformed variable content\n");
822                 return -EINVAL;
823         }
824
825         spin_lock(&efivars->lock);
826
827         /*
828          * Does this variable already exist?
829          */
830         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
831                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
832                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
833                 if (strsize1 == strsize2 &&
834                         !memcmp(&(search_efivar->var.VariableName),
835                                 new_var->VariableName, strsize1) &&
836                         !efi_guidcmp(search_efivar->var.VendorGuid,
837                                 new_var->VendorGuid)) {
838                         found = 1;
839                         break;
840                 }
841         }
842         if (found) {
843                 spin_unlock(&efivars->lock);
844                 return -EINVAL;
845         }
846
847         /* now *really* create the variable via EFI */
848         status = efivars->ops->set_variable(new_var->VariableName,
849                                             &new_var->VendorGuid,
850                                             new_var->Attributes,
851                                             new_var->DataSize,
852                                             new_var->Data);
853
854         if (status != EFI_SUCCESS) {
855                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
856                         status);
857                 spin_unlock(&efivars->lock);
858                 return -EIO;
859         }
860         spin_unlock(&efivars->lock);
861
862         /* Create the entry in sysfs.  Locking is not required here */
863         status = efivar_create_sysfs_entry(efivars,
864                                            utf16_strsize(new_var->VariableName,
865                                                          1024),
866                                            new_var->VariableName,
867                                            &new_var->VendorGuid);
868         if (status) {
869                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
870         }
871         return count;
872 }
873
874 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
875                              struct bin_attribute *bin_attr,
876                              char *buf, loff_t pos, size_t count)
877 {
878         struct efi_variable *del_var = (struct efi_variable *)buf;
879         struct efivars *efivars = bin_attr->private;
880         struct efivar_entry *search_efivar, *n;
881         unsigned long strsize1, strsize2;
882         efi_status_t status = EFI_NOT_FOUND;
883         int found = 0;
884
885         if (!capable(CAP_SYS_ADMIN))
886                 return -EACCES;
887
888         spin_lock(&efivars->lock);
889
890         /*
891          * Does this variable already exist?
892          */
893         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
894                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
895                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
896                 if (strsize1 == strsize2 &&
897                         !memcmp(&(search_efivar->var.VariableName),
898                                 del_var->VariableName, strsize1) &&
899                         !efi_guidcmp(search_efivar->var.VendorGuid,
900                                 del_var->VendorGuid)) {
901                         found = 1;
902                         break;
903                 }
904         }
905         if (!found) {
906                 spin_unlock(&efivars->lock);
907                 return -EINVAL;
908         }
909         /* force the Attributes/DataSize to 0 to ensure deletion */
910         del_var->Attributes = 0;
911         del_var->DataSize = 0;
912
913         status = efivars->ops->set_variable(del_var->VariableName,
914                                             &del_var->VendorGuid,
915                                             del_var->Attributes,
916                                             del_var->DataSize,
917                                             del_var->Data);
918
919         if (status != EFI_SUCCESS) {
920                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
921                         status);
922                 spin_unlock(&efivars->lock);
923                 return -EIO;
924         }
925         list_del(&search_efivar->list);
926         /* We need to release this lock before unregistering. */
927         spin_unlock(&efivars->lock);
928         efivar_unregister(search_efivar);
929
930         /* It's dead Jim.... */
931         return count;
932 }
933
934 /*
935  * Let's not leave out systab information that snuck into
936  * the efivars driver
937  */
938 static ssize_t systab_show(struct kobject *kobj,
939                            struct kobj_attribute *attr, char *buf)
940 {
941         char *str = buf;
942
943         if (!kobj || !buf)
944                 return -EINVAL;
945
946         if (efi.mps != EFI_INVALID_TABLE_ADDR)
947                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
948         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
949                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
950         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
951                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
952         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
953                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
954         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
955                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
956         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
957                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
958         if (efi.uga != EFI_INVALID_TABLE_ADDR)
959                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
960
961         return str - buf;
962 }
963
964 static struct kobj_attribute efi_attr_systab =
965                         __ATTR(systab, 0400, systab_show, NULL);
966
967 static struct attribute *efi_subsys_attrs[] = {
968         &efi_attr_systab.attr,
969         NULL,   /* maybe more in the future? */
970 };
971
972 static struct attribute_group efi_subsys_attr_group = {
973         .attrs = efi_subsys_attrs,
974 };
975
976 static struct kobject *efi_kobj;
977
978 /*
979  * efivar_create_sysfs_entry()
980  * Requires:
981  *    variable_name_size = number of bytes required to hold
982  *                         variable_name (not counting the NULL
983  *                         character at the end.
984  *    efivars->lock is not held on entry or exit.
985  * Returns 1 on failure, 0 on success
986  */
987 static int
988 efivar_create_sysfs_entry(struct efivars *efivars,
989                           unsigned long variable_name_size,
990                           efi_char16_t *variable_name,
991                           efi_guid_t *vendor_guid)
992 {
993         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
994         char *short_name;
995         struct efivar_entry *new_efivar;
996
997         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
998         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
999
1000         if (!short_name || !new_efivar)  {
1001                 kfree(short_name);
1002                 kfree(new_efivar);
1003                 return 1;
1004         }
1005
1006         new_efivar->efivars = efivars;
1007         memcpy(new_efivar->var.VariableName, variable_name,
1008                 variable_name_size);
1009         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1010
1011         /* Convert Unicode to normal chars (assume top bits are 0),
1012            ala UTF-8 */
1013         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1014                 short_name[i] = variable_name[i] & 0xFF;
1015         }
1016         /* This is ugly, but necessary to separate one vendor's
1017            private variables from another's.         */
1018
1019         *(short_name + strlen(short_name)) = '-';
1020         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1021
1022         new_efivar->kobj.kset = efivars->kset;
1023         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1024                                  "%s", short_name);
1025         if (i) {
1026                 kfree(short_name);
1027                 kfree(new_efivar);
1028                 return 1;
1029         }
1030
1031         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1032         kfree(short_name);
1033         short_name = NULL;
1034
1035         spin_lock(&efivars->lock);
1036         list_add(&new_efivar->list, &efivars->list);
1037         spin_unlock(&efivars->lock);
1038
1039         return 0;
1040 }
1041
1042 static int
1043 create_efivars_bin_attributes(struct efivars *efivars)
1044 {
1045         struct bin_attribute *attr;
1046         int error;
1047
1048         /* new_var */
1049         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1050         if (!attr)
1051                 return -ENOMEM;
1052
1053         attr->attr.name = "new_var";
1054         attr->attr.mode = 0200;
1055         attr->write = efivar_create;
1056         attr->private = efivars;
1057         efivars->new_var = attr;
1058
1059         /* del_var */
1060         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1061         if (!attr) {
1062                 error = -ENOMEM;
1063                 goto out_free;
1064         }
1065         attr->attr.name = "del_var";
1066         attr->attr.mode = 0200;
1067         attr->write = efivar_delete;
1068         attr->private = efivars;
1069         efivars->del_var = attr;
1070
1071         sysfs_bin_attr_init(efivars->new_var);
1072         sysfs_bin_attr_init(efivars->del_var);
1073
1074         /* Register */
1075         error = sysfs_create_bin_file(&efivars->kset->kobj,
1076                                       efivars->new_var);
1077         if (error) {
1078                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1079                         " due to error %d\n", error);
1080                 goto out_free;
1081         }
1082         error = sysfs_create_bin_file(&efivars->kset->kobj,
1083                                       efivars->del_var);
1084         if (error) {
1085                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1086                         " due to error %d\n", error);
1087                 sysfs_remove_bin_file(&efivars->kset->kobj,
1088                                       efivars->new_var);
1089                 goto out_free;
1090         }
1091
1092         return 0;
1093 out_free:
1094         kfree(efivars->del_var);
1095         efivars->del_var = NULL;
1096         kfree(efivars->new_var);
1097         efivars->new_var = NULL;
1098         return error;
1099 }
1100
1101 void unregister_efivars(struct efivars *efivars)
1102 {
1103         struct efivar_entry *entry, *n;
1104
1105         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1106                 spin_lock(&efivars->lock);
1107                 list_del(&entry->list);
1108                 spin_unlock(&efivars->lock);
1109                 efivar_unregister(entry);
1110         }
1111         if (efivars->new_var)
1112                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1113         if (efivars->del_var)
1114                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1115         kfree(efivars->new_var);
1116         kfree(efivars->del_var);
1117         kset_unregister(efivars->kset);
1118 }
1119 EXPORT_SYMBOL_GPL(unregister_efivars);
1120
1121 int register_efivars(struct efivars *efivars,
1122                      const struct efivar_operations *ops,
1123                      struct kobject *parent_kobj)
1124 {
1125         efi_status_t status = EFI_NOT_FOUND;
1126         efi_guid_t vendor_guid;
1127         efi_char16_t *variable_name;
1128         unsigned long variable_name_size = 1024;
1129         int error = 0;
1130
1131         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1132         if (!variable_name) {
1133                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1134                 return -ENOMEM;
1135         }
1136
1137         spin_lock_init(&efivars->lock);
1138         INIT_LIST_HEAD(&efivars->list);
1139         efivars->ops = ops;
1140
1141         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1142         if (!efivars->kset) {
1143                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1144                 error = -ENOMEM;
1145                 goto out;
1146         }
1147
1148         /*
1149          * Per EFI spec, the maximum storage allocated for both
1150          * the variable name and variable data is 1024 bytes.
1151          */
1152
1153         do {
1154                 variable_name_size = 1024;
1155
1156                 status = ops->get_next_variable(&variable_name_size,
1157                                                 variable_name,
1158                                                 &vendor_guid);
1159                 switch (status) {
1160                 case EFI_SUCCESS:
1161                         efivar_create_sysfs_entry(efivars,
1162                                                   variable_name_size,
1163                                                   variable_name,
1164                                                   &vendor_guid);
1165                         break;
1166                 case EFI_NOT_FOUND:
1167                         break;
1168                 default:
1169                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1170                                 status);
1171                         status = EFI_NOT_FOUND;
1172                         break;
1173                 }
1174         } while (status != EFI_NOT_FOUND);
1175
1176         error = create_efivars_bin_attributes(efivars);
1177         if (error)
1178                 unregister_efivars(efivars);
1179
1180         efivars->efi_pstore_info = efi_pstore_info;
1181
1182         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1183         if (efivars->efi_pstore_info.buf) {
1184                 efivars->efi_pstore_info.bufsize = 1024;
1185                 efivars->efi_pstore_info.data = efivars;
1186                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1187                 pstore_register(&efivars->efi_pstore_info);
1188         }
1189
1190 out:
1191         kfree(variable_name);
1192
1193         return error;
1194 }
1195 EXPORT_SYMBOL_GPL(register_efivars);
1196
1197 static struct efivars __efivars;
1198 static struct efivar_operations ops;
1199
1200 /*
1201  * For now we register the efi subsystem with the firmware subsystem
1202  * and the vars subsystem with the efi subsystem.  In the future, it
1203  * might make sense to split off the efi subsystem into its own
1204  * driver, but for now only efivars will register with it, so just
1205  * include it here.
1206  */
1207
1208 static int __init
1209 efivars_init(void)
1210 {
1211         int error = 0;
1212
1213         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1214                EFIVARS_DATE);
1215
1216         if (!efi_enabled)
1217                 return 0;
1218
1219         /* For now we'll register the efi directory at /sys/firmware/efi */
1220         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1221         if (!efi_kobj) {
1222                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1223                 return -ENOMEM;
1224         }
1225
1226         ops.get_variable = efi.get_variable;
1227         ops.set_variable = efi.set_variable;
1228         ops.get_next_variable = efi.get_next_variable;
1229         error = register_efivars(&__efivars, &ops, efi_kobj);
1230         if (error)
1231                 goto err_put;
1232
1233         /* Don't forget the systab entry */
1234         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1235         if (error) {
1236                 printk(KERN_ERR
1237                        "efivars: Sysfs attribute export failed with error %d.\n",
1238                        error);
1239                 goto err_unregister;
1240         }
1241
1242         return 0;
1243
1244 err_unregister:
1245         unregister_efivars(&__efivars);
1246 err_put:
1247         kobject_put(efi_kobj);
1248         return error;
1249 }
1250
1251 static void __exit
1252 efivars_exit(void)
1253 {
1254         if (efi_enabled) {
1255                 unregister_efivars(&__efivars);
1256                 kobject_put(efi_kobj);
1257         }
1258 }
1259
1260 module_init(efivars_init);
1261 module_exit(efivars_exit);
1262