lib/libefivar/efivar.c

   1 /*-
   2  * Copyright (c) 2016 Netflix, Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  *
  25  * $FreeBSD: head/lib/libefivar/efivar.c 343755 2019-02-04 21:28:25Z imp $
  26  */
  27
  28 #include <efivar.h>
  29 #include <sys/efiio.h>
  30 #include <sys/param.h>
  31 #include <errno.h>
  32 #include <fcntl.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include "libefivar_int.h"
  38
  39 static int efi_fd = -2;
  40
  41 #define Z { 0, 0, 0, 0, 0, { 0 } }
  42
  43 const efi_guid_t efi_guid_empty = Z;
  44
  45 static struct uuid_table guid_tbl [] =
  46 {
  47         { "00000000-0000-0000-0000-000000000000", "zero", Z },
  48         { "093e0fae-a6c4-4f50-9f1b-d41e2b89c19a", "sha512", Z },
  49         { "0abba7dc-e516-4167-bbf5-4d9d1c739416", "redhat", Z },
  50         { "0b6e5233-a65c-44c9-9407-d9ab83bfc8bd", "sha224", Z },
  51         { "126a762d-5758-4fca-8531-201a7f57f850", "lenovo_boot_menu", Z },
  52         { "3bd2a492-96c0-4079-b420-fcf98ef103ed", "x509_sha256", Z },
  53         { "3c5766e8-269c-4e34-aa14-ed776e85b3b6", "rsa2048", Z },
  54         { "3CC24E96-22C7-41D8-8863-8E39DCDCC2CF", "lenovo", Z },
  55         { "3f7e615b-0d45-4f80-88dc-26b234958560", "lenovo_diag", Z },
  56         { "446dbf63-2502-4cda-bcfa-2465d2b0fe9d", "x509_sha512", Z },
  57         { "4aafd29d-68df-49ee-8aa9-347d375665a7", "pkcs7_cert", Z },
  58         { "605dab50-e046-4300-abb6-3dd810dd8b23", "shim", Z },
  59         { "665d3f60-ad3e-4cad-8e26-db46eee9f1b5", "lenovo_rescue", Z },
  60         { "67f8444f-8743-48f1-a328-1eaab8736080", "rsa2048_sha1", Z },
  61         { "7076876e-80c2-4ee6-aad2-28b349a6865b", "x509_sha384", Z },
  62         { "721c8b66-426c-4e86-8e99-3457c46ab0b9", "lenovo_setup", Z },
  63         { "77fa9abd-0359-4d32-bd60-28f4e78f784b", "microsoft", Z },
  64         { "7FACC7B6-127F-4E9C-9C5D-080F98994345", "lenovo_2", Z },
  65         { "826ca512-cf10-4ac9-b187-be01496631bd", "sha1", Z },
  66         { "82988420-7467-4490-9059-feb448dd1963", "lenovo_me_config", Z },
  67         { "8be4df61-93ca-11d2-aa0d-00e098032b8c", "global", Z },
  68         { "a5c059a1-94e4-4aa7-87b5-ab155c2bf072", "x509_cert", Z },
  69         { "a7717414-c616-4977-9420-844712a735bf", "rsa2048_sha256_cert", Z },
  70         { "a7d8d9a6-6ab0-4aeb-ad9d-163e59a7a380", "lenovo_diag_splash", Z },
  71         { "ade9e48f-9cb8-98e6-31af-b4e6009e2fe3", "redhat_2", Z },
  72         { "bc7838d2-0f82-4d60-8316-c068ee79d25b", "lenovo_msg", Z },
  73         { "c1c41626-504c-4092-aca9-41f936934328", "sha256", Z },
  74         { "c57ad6b7-0515-40a8-9d21-551652854e37", "shell", Z },
  75         { "d719b2cb-3d3a-4596-a3bc-dad00e67656f", "security", Z },
  76         { "e2b36190-879b-4a3d-ad8d-f2e7bba32784", "rsa2048_sha256", Z },
  77         { "ff3e5307-9fd0-48c9-85f1-8ad56c701e01", "sha384", Z },
  78         { "f46ee6f4-4785-43a3-923d-7f786c3c8479", "lenovo_startup_interrupt", Z },
  79         { "ffffffff-ffff-ffff-ffff-ffffffffffff", "zzignore-this-guid", Z },
  80 };
  81 #undef Z
  82
  83 static void
  84 efi_guid_tbl_compile(void)
  85 {
  86         size_t i;
  87         uint32_t status;
  88         static int done = 0;
  89
  90         if (done)
  91                 return;
  92         for (i = 0; i < nitems(guid_tbl); i++) {
  93                 uuid_from_string(guid_tbl[i].uuid_str, &guid_tbl[i].guid,
  94                     &status);
  95                 /* all f's is a bad version, so ignore that error */
  96                 if (status != uuid_s_ok && status != uuid_s_bad_version)
  97                         fprintf(stderr, "Can't convert %s to a uuid for %s: %d\n",
  98                             guid_tbl[i].uuid_str, guid_tbl[i].name, (int)status);
  99         }
 100         done = 1;
 101 }
 102
 103 int
 104 efi_known_guid(struct uuid_table **tbl)
 105 {
 106
 107         *tbl = guid_tbl;
 108         return (nitems(guid_tbl));
 109 }
 110
 111 static int
 112 efi_open_dev(void)
 113 {
 114
 115         if (efi_fd == -2)
 116                 efi_fd = open("/dev/efi", O_RDWR);
 117         if (efi_fd < 0)
 118                 efi_fd = -1;
 119         else
 120                 efi_guid_tbl_compile();
 121         return (efi_fd);
 122 }
 123
 124 static void
 125 efi_var_reset(struct efi_var_ioc *var)
 126 {
 127         var->name = NULL;
 128         var->namesize = 0;
 129         memset(&var->vendor, 0, sizeof(var->vendor));
 130         var->attrib = 0;
 131         var->data = NULL;
 132         var->datasize = 0;
 133 }
 134
 135 static int
 136 rv_to_linux_rv(int rv)
 137 {
 138         if (rv == 0)
 139                 rv = 1;
 140         else
 141                 rv = -errno;
 142         return (rv);
 143 }
 144
 145 int
 146 efi_append_variable(efi_guid_t guid, const char *name,
 147     uint8_t *data, size_t data_size, uint32_t attributes)
 148 {
 149
 150         return efi_set_variable(guid, name, data, data_size,
 151             attributes | EFI_VARIABLE_APPEND_WRITE);
 152 }
 153
 154 int
 155 efi_del_variable(efi_guid_t guid, const char *name)
 156 {
 157
 158         /* data_size of 0 deletes the variable */
 159         return efi_set_variable(guid, name, NULL, 0, 0);
 160 }
 161
 162 int
 163 efi_get_variable(efi_guid_t guid, const char *name,
 164     uint8_t **data, size_t *data_size, uint32_t *attributes)
 165 {
 166         struct efi_var_ioc var;
 167         int rv;
 168         static uint8_t buf[1024*32];
 169
 170         if (efi_open_dev() == -1)
 171                 return -1;
 172
 173         efi_var_reset(&var);
 174         rv = utf8_to_ucs2(name, &var.name, &var.namesize);
 175         if (rv != 0)
 176                 goto errout;
 177         var.vendor = guid;
 178         var.data = buf;
 179         var.datasize = sizeof(buf);
 180         rv = ioctl(efi_fd, EFIIOC_VAR_GET, &var);
 181         if (data_size != NULL)
 182                 *data_size = var.datasize;
 183         if (data != NULL)
 184                 *data = buf;
 185         if (attributes != NULL)
 186                 *attributes = var.attrib;
 187 errout:
 188         free(var.name);
 189
 190         return rv_to_linux_rv(rv);
 191 }
 192
 193 int
 194 efi_get_variable_attributes(efi_guid_t guid, const char *name,
 195     uint32_t *attributes)
 196 {
 197         /* Make sure this construct works -- I think it will fail */
 198
 199         return efi_get_variable(guid, name, NULL, NULL, attributes);
 200 }
 201
 202 int
 203 efi_get_variable_size(efi_guid_t guid, const char *name,
 204     size_t *size)
 205 {
 206
 207         /* XXX check to make sure this matches the linux value */
 208
 209         *size = 0;
 210         return efi_get_variable(guid, name, NULL, size, NULL);
 211 }
 212
 213 int
 214 efi_get_next_variable_name(efi_guid_t **guid, char **name)
 215 {
 216         struct efi_var_ioc var;
 217         int rv;
 218         static efi_char *buf;
 219         static size_t buflen = 256 * sizeof(efi_char);
 220         static efi_guid_t retguid;
 221         size_t size;
 222
 223         if (efi_open_dev() == -1)
 224                 return -1;
 225
 226         /*
 227          * Always allocate enough for an extra NUL on the end, but don't tell
 228          * the IOCTL about it so we can NUL terminate the name before converting
 229          * it to UTF8.
 230          */
 231         if (buf == NULL)
 232                 buf = malloc(buflen + sizeof(efi_char));
 233
 234 again:
 235         efi_var_reset(&var);
 236         var.name = buf;
 237         var.namesize = buflen;
 238         if (*name == NULL) {
 239                 *buf = 0;
 240                 /* GUID zeroed in var_reset */
 241         } else {
 242                 rv = utf8_to_ucs2(*name, &var.name, &size);
 243                 if (rv != 0)
 244                         goto errout;
 245                 var.vendor = **guid;
 246         }
 247         rv = ioctl(efi_fd, EFIIOC_VAR_NEXT, &var);
 248         if (rv == 0 && var.name == NULL) {
 249                 /*
 250                  * Variable name not long enough, so allocate more space for the
 251                  * name and try again. As above, mind the NUL we add.
 252                  */
 253                 void *new = realloc(buf, var.namesize + sizeof(efi_char));
 254                 if (new == NULL) {
 255                         rv = -1;
 256                         errno = ENOMEM;
 257                         goto done;
 258                 }
 259                 buflen = var.namesize;
 260                 buf = new;
 261                 goto again;
 262         }
 263
 264         if (rv == 0) {
 265                 free(*name);                    /* Free last name, to avoid leaking */
 266                 *name = NULL;                   /* Force ucs2_to_utf8 to malloc new space */
 267                 var.name[var.namesize / sizeof(efi_char)] = 0;  /* EFI doesn't NUL terminate */
 268                 rv = ucs2_to_utf8(var.name, name);
 269                 if (rv != 0)
 270                         goto errout;
 271                 retguid = var.vendor;
 272                 *guid = &retguid;
 273         }
 274 errout:
 275
 276         /* XXX The linux interface expects name to be a static buffer -- fix or leak memory? */
 277         /* XXX for the moment, we free just before we'd leak, but still leak last one */
 278 done:
 279         if (rv != 0 && errno == ENOENT) {
 280                 errno = 0;
 281                 free(*name);                    /* Free last name, to avoid leaking */
 282                 return 0;
 283         }
 284
 285         return (rv_to_linux_rv(rv));
 286 }
 287
 288 int
 289 efi_guid_cmp(const efi_guid_t *guid1, const efi_guid_t *guid2)
 290 {
 291         uint32_t status;
 292
 293         return uuid_compare(guid1, guid2, &status);
 294 }
 295
 296 int
 297 efi_guid_is_zero(const efi_guid_t *guid)
 298 {
 299         uint32_t status;
 300
 301         return uuid_is_nil(guid, &status);
 302 }
 303
 304 int
 305 efi_guid_to_name(efi_guid_t *guid, char **name)
 306 {
 307         size_t i;
 308         uint32_t status;
 309
 310         efi_guid_tbl_compile();
 311         for (i = 0; i < nitems(guid_tbl); i++) {
 312                 if (uuid_equal(guid, &guid_tbl[i].guid, &status)) {
 313                         *name = strdup(guid_tbl[i].name);
 314                         return (0);
 315                 }
 316         }
 317         return (efi_guid_to_str(guid, name));
 318 }
 319
 320 int
 321 efi_guid_to_symbol(efi_guid_t *guid __unused, char **symbol __unused)
 322 {
 323
 324         /*
 325          * Unsure what this is used for, efibootmgr doesn't use it.
 326          * Leave unimplemented for now.
 327          */
 328         return -1;
 329 }
 330
 331 int
 332 efi_guid_to_str(const efi_guid_t *guid, char **sp)
 333 {
 334         uint32_t status;
 335
 336         /* knows efi_guid_t is a typedef of uuid_t */
 337         uuid_to_string(guid, sp, &status);
 338
 339         return (status == uuid_s_ok ? 0 : -1);
 340 }
 341
 342 int
 343 efi_name_to_guid(const char *name, efi_guid_t *guid)
 344 {
 345         size_t i;
 346
 347         efi_guid_tbl_compile();
 348         for (i = 0; i < nitems(guid_tbl); i++) {
 349                 if (strcmp(name, guid_tbl[i].name) == 0) {
 350                         *guid = guid_tbl[i].guid;
 351                         return (0);
 352                 }
 353         }
 354         return (efi_str_to_guid(name, guid));
 355 }
 356
 357 int
 358 efi_set_variable(efi_guid_t guid, const char *name,
 359     uint8_t *data, size_t data_size, uint32_t attributes)
 360 {
 361         struct efi_var_ioc var;
 362         int rv;
 363
 364         if (efi_open_dev() == -1)
 365                 return -1;
 366
 367         efi_var_reset(&var);
 368         rv = utf8_to_ucs2(name, &var.name, &var.namesize);
 369         if (rv != 0)
 370                 goto errout;
 371         var.vendor = guid;
 372         var.data = data;
 373         var.datasize = data_size;
 374         var.attrib = attributes;
 375         rv = ioctl(efi_fd, EFIIOC_VAR_SET, &var);
 376 errout:
 377         free(var.name);
 378
 379         return rv;
 380 }
 381
 382 int
 383 efi_str_to_guid(const char *s, efi_guid_t *guid)
 384 {
 385         uint32_t status;
 386
 387         /* knows efi_guid_t is a typedef of uuid_t */
 388         uuid_from_string(s, guid, &status);
 389
 390         return (status == uuid_s_ok ? 0 : -1);
 391 }
 392
 393 int
 394 efi_variables_supported(void)
 395 {
 396
 397         return efi_open_dev() != -1;
 398 }