lib/libefivar/efivar.c

   1 /*-
   2  * Copyright (c) 2016 Netflix, Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD: head/lib/libefivar/efivar.c 307189 2016-10-13 06:56:23Z imp $");
  29
  30 #include <efivar.h>
  31 #include <sys/efiio.h>
  32 #include <sys/param.h>
  33 #include <errno.h>
  34 #include <fcntl.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include "libefivar_int.h"
  40
  41 static int efi_fd = -2;
  42
  43 #define Z { 0, 0, 0, 0, 0, { 0 } }
  44
  45 const efi_guid_t efi_guid_empty = Z;
  46
  47 static struct uuid_table
  48 {
  49         const char *uuid_str;
  50         const char *name;
  51         efi_guid_t guid;
  52 } guid_tbl [] =
  53 {
  54         { "00000000-0000-0000-0000-000000000000", "zero", Z },
  55         { "093e0fae-a6c4-4f50-9f1b-d41e2b89c19a", "sha512", Z },
  56         { "0abba7dc-e516-4167-bbf5-4d9d1c739416", "redhat", Z },
  57         { "0b6e5233-a65c-44c9-9407-d9ab83bfc8bd", "sha224", Z },
  58         { "126a762d-5758-4fca-8531-201a7f57f850", "lenovo_boot_menu", Z },
  59         { "3bd2a492-96c0-4079-b420-fcf98ef103ed", "x509_sha256", Z },
  60         { "3c5766e8-269c-4e34-aa14-ed776e85b3b6", "rsa2048", Z },
  61         { "3CC24E96-22C7-41D8-8863-8E39DCDCC2CF", "lenovo", Z },
  62         { "3f7e615b-0d45-4f80-88dc-26b234958560", "lenovo_diag", Z },
  63         { "446dbf63-2502-4cda-bcfa-2465d2b0fe9d", "x509_sha512", Z },
  64         { "4aafd29d-68df-49ee-8aa9-347d375665a7", "pkcs7_cert", Z },
  65         { "605dab50-e046-4300-abb6-3dd810dd8b23", "shim", Z },
  66         { "665d3f60-ad3e-4cad-8e26-db46eee9f1b5", "lenovo_rescue", Z },
  67         { "67f8444f-8743-48f1-a328-1eaab8736080", "rsa2048_sha1", Z },
  68         { "7076876e-80c2-4ee6-aad2-28b349a6865b", "x509_sha384", Z },
  69         { "721c8b66-426c-4e86-8e99-3457c46ab0b9", "lenovo_setup", Z },
  70         { "77fa9abd-0359-4d32-bd60-28f4e78f784b", "microsoft", Z },
  71         { "7FACC7B6-127F-4E9C-9C5D-080F98994345", "lenovo_2", Z },
  72         { "826ca512-cf10-4ac9-b187-be01496631bd", "sha1", Z },
  73         { "82988420-7467-4490-9059-feb448dd1963", "lenovo_me_config", Z },
  74         { "8be4df61-93ca-11d2-aa0d-00e098032b8c", "global", Z },
  75         { "a5c059a1-94e4-4aa7-87b5-ab155c2bf072", "x509_cert", Z },
  76         { "a7717414-c616-4977-9420-844712a735bf", "rsa2048_sha256_cert", Z },
  77         { "a7d8d9a6-6ab0-4aeb-ad9d-163e59a7a380", "lenovo_diag_splash", Z },
  78         { "ade9e48f-9cb8-98e6-31af-b4e6009e2fe3", "redhat_2", Z },
  79         { "bc7838d2-0f82-4d60-8316-c068ee79d25b", "lenovo_msg", Z },
  80         { "c1c41626-504c-4092-aca9-41f936934328", "sha256", Z },
  81         { "c57ad6b7-0515-40a8-9d21-551652854e37", "shell", Z },
  82         { "d719b2cb-3d3a-4596-a3bc-dad00e67656f", "security", Z },
  83         { "e2b36190-879b-4a3d-ad8d-f2e7bba32784", "rsa2048_sha256", Z },
  84         { "ff3e5307-9fd0-48c9-85f1-8ad56c701e01", "sha384", Z },
  85         { "f46ee6f4-4785-43a3-923d-7f786c3c8479", "lenovo_startup_interrupt", Z },
  86         { "ffffffff-ffff-ffff-ffff-ffffffffffff", "zzignore-this-guid", Z },
  87 };
  88 #undef Z
  89
  90 static void
  91 efi_guid_tbl_compile(void)
  92 {
  93         size_t i;
  94         uint32_t status;
  95
  96         for (i = 0; i < nitems(guid_tbl); i++) {
  97                 uuid_from_string(guid_tbl[i].uuid_str, &guid_tbl[i].guid,
  98                     &status);
  99                 /* all f's is a bad version, so ignore that error */
 100                 if (status != uuid_s_ok && status != uuid_s_bad_version)
 101                         fprintf(stderr, "Can't convert %s to a uuid for %s: %d\n",
 102                             guid_tbl[i].uuid_str, guid_tbl[i].name, (int)status);
 103         }
 104 }
 105
 106 static int
 107 efi_open_dev(void)
 108 {
 109
 110         if (efi_fd == -2)
 111                 efi_fd = open("/dev/efi", O_RDWR);
 112         if (efi_fd < 0)
 113                 efi_fd = -1;
 114         else
 115                 efi_guid_tbl_compile();
 116         return (efi_fd);
 117 }
 118
 119 static void
 120 efi_var_reset(struct efi_var_ioc *var)
 121 {
 122         var->name = NULL;
 123         var->namesize = 0;
 124         memset(&var->vendor, 0, sizeof(var->vendor));
 125         var->attrib = 0;
 126         var->data = NULL;
 127         var->datasize = 0;
 128 }
 129
 130 static int
 131 rv_to_linux_rv(int rv)
 132 {
 133         if (rv == 0)
 134                 rv = 1;
 135         else if (errno == ENOENT) {
 136                 rv = 0;
 137                 errno = 0;
 138         } else
 139                 rv = -errno;
 140         return (rv);
 141 }
 142
 143 int
 144 efi_append_variable(efi_guid_t guid, const char *name,
 145     uint8_t *data, size_t data_size, uint32_t attributes)
 146 {
 147
 148         return efi_set_variable(guid, name, data, data_size,
 149             attributes | EFI_VARIABLE_APPEND_WRITE, 0);
 150 }
 151
 152 int
 153 efi_del_variable(efi_guid_t guid, const char *name)
 154 {
 155
 156         /* data_size of 0 deletes the variable */
 157         return efi_set_variable(guid, name, NULL, 0, 0, 0);
 158 }
 159
 160 int
 161 efi_get_variable(efi_guid_t guid, const char *name,
 162     uint8_t **data, size_t *data_size, uint32_t *attributes)
 163 {
 164         struct efi_var_ioc var;
 165         int rv;
 166         static uint8_t buf[1024*32];
 167
 168         if (efi_open_dev() == -1)
 169                 return -1;
 170
 171         efi_var_reset(&var);
 172         rv = libefi_utf8_to_ucs2(name, &var.name, &var.namesize);
 173         if (rv != 0)
 174                 goto errout;
 175         var.vendor = guid;
 176         var.data = buf;
 177         var.datasize = sizeof(buf);
 178         rv = ioctl(efi_fd, EFIIOC_VAR_GET, &var);
 179         if (data_size != NULL)
 180                 *data_size = var.datasize;
 181         if (data != NULL)
 182                 *data = buf;
 183         if (attributes != NULL)
 184                 *attributes = var.attrib;
 185 errout:
 186         free(var.name);
 187
 188         return rv_to_linux_rv(rv);
 189 }
 190
 191 int
 192 efi_get_variable_attributes(efi_guid_t guid, const char *name,
 193     uint32_t *attributes)
 194 {
 195         /* Make sure this construct works -- I think it will fail */
 196
 197         return efi_get_variable(guid, name, NULL, NULL, attributes);
 198 }
 199
 200 int
 201 efi_get_variable_size(efi_guid_t guid, const char *name,
 202     size_t *size)
 203 {
 204
 205         /* XXX check to make sure this matches the linux value */
 206
 207         *size = 0;
 208         return efi_get_variable(guid, name, NULL, size, NULL);
 209 }
 210
 211 int
 212 efi_get_next_variable_name(efi_guid_t **guid, char **name)
 213 {
 214         struct efi_var_ioc var;
 215         int rv;
 216         static efi_char *buf;
 217         static size_t buflen = 256 * sizeof(efi_char);
 218         static efi_guid_t retguid;
 219         size_t size;
 220
 221         if (efi_open_dev() == -1)
 222                 return -1;
 223
 224
 225         if (buf == NULL)
 226                 buf = malloc(buflen);
 227
 228 again:
 229         efi_var_reset(&var);
 230         var.name = buf;
 231         var.namesize = buflen;
 232         if (*name == NULL) {
 233                 *buf = 0;
 234                 /* GUID zeroed in var_reset */
 235         } else {
 236                 rv = libefi_utf8_to_ucs2(*name, &var.name, &size);
 237                 if (rv != 0)
 238                         goto errout;
 239                 var.vendor = **guid;
 240         }
 241         rv = ioctl(efi_fd, EFIIOC_VAR_NEXT, &var);
 242         if (rv == 0 && var.name == NULL) {
 243                 /*
 244                  * oops, too little space. Try again.
 245                  */
 246                 void *new = realloc(buf, buflen);
 247                 buflen = var.namesize;
 248                 if (new == NULL) {
 249                         rv = -1;
 250                         errno = ENOMEM;
 251                         goto done;
 252                 }
 253                 buf = new;
 254                 goto again;
 255         }
 256
 257         if (rv == 0) {
 258                 *name = NULL; /* XXX */
 259                 var.name[var.namesize / sizeof(efi_char)] = 0;  /* EFI doesn't NUL terminate */
 260                 rv = libefi_ucs2_to_utf8(var.name, name);
 261                 if (rv != 0)
 262                         goto errout;
 263                 retguid = var.vendor;
 264                 *guid = &retguid;
 265         }
 266 errout:
 267
 268         /* XXX The linux interface expects name to be a static buffer -- fix or leak memory? */
 269 done:
 270         return (rv_to_linux_rv(rv));
 271 }
 272
 273 int
 274 efi_guid_cmp(const efi_guid_t *guid1, const efi_guid_t *guid2)
 275 {
 276         uint32_t status;
 277
 278         return uuid_compare(guid1, guid2, &status);
 279 }
 280
 281 int
 282 efi_guid_is_zero(const efi_guid_t *guid)
 283 {
 284         uint32_t status;
 285
 286         return uuid_is_nil(guid, &status);
 287 }
 288
 289 int
 290 efi_guid_to_name(efi_guid_t *guid, char **name)
 291 {
 292         size_t i;
 293         uint32_t status;
 294
 295         for (i = 0; i < nitems(guid_tbl); i++) {
 296                 if (uuid_equal(guid, &guid_tbl[i].guid, &status)) {
 297                         *name = strdup(guid_tbl[i].name);
 298                         return (0);
 299                 }
 300         }
 301         return (efi_guid_to_str(guid, name));
 302 }
 303
 304 int
 305 efi_guid_to_symbol(efi_guid_t *guid __unused, char **symbol __unused)
 306 {
 307
 308         /*
 309          * Unsure what this is used for, efibootmgr doesn't use it.
 310          * Leave unimplemented for now.
 311          */
 312         return -1;
 313 }
 314
 315 int
 316 efi_guid_to_str(const efi_guid_t *guid, char **sp)
 317 {
 318         uint32_t status;
 319
 320         /* knows efi_guid_t is a typedef of uuid_t */
 321         uuid_to_string(guid, sp, &status);
 322
 323         return (status == uuid_s_ok ? 0 : -1);
 324 }
 325
 326 int
 327 efi_name_to_guid(const char *name, efi_guid_t *guid)
 328 {
 329         size_t i;
 330
 331         for (i = 0; i < nitems(guid_tbl); i++) {
 332                 if (strcmp(name, guid_tbl[i].name) == 0) {
 333                         *guid = guid_tbl[i].guid;
 334                         return (0);
 335                 }
 336         }
 337         return (efi_str_to_guid(name, guid));
 338 }
 339
 340 int
 341 efi_set_variable(efi_guid_t guid, const char *name,
 342     uint8_t *data, size_t data_size, uint32_t attributes, mode_t mode __unused)
 343 {
 344         struct efi_var_ioc var;
 345         int rv;
 346
 347         if (efi_open_dev() == -1)
 348                 return -1;
 349
 350         efi_var_reset(&var);
 351         rv = libefi_utf8_to_ucs2(name, &var.name, &var.namesize);
 352         if (rv != 0)
 353                 goto errout;
 354         var.vendor = guid;
 355         var.data = data;
 356         var.datasize = data_size;
 357         var.attrib = attributes;
 358         rv = ioctl(efi_fd, EFIIOC_VAR_SET, &var);
 359 errout:
 360         free(var.name);
 361
 362         return rv;
 363 }
 364
 365 int
 366 efi_str_to_guid(const char *s, efi_guid_t *guid)
 367 {
 368         uint32_t status;
 369
 370         /* knows efi_guid_t is a typedef of uuid_t */
 371         uuid_from_string(s, guid, &status);
 372
 373         return (status == uuid_s_ok ? 0 : -1);
 374 }
 375
 376 int
 377 efi_variables_supported(void)
 378 {
 379
 380         return efi_open_dev() != -1;
 381 }