extras/volume_id/lib/luks.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2005 W. Michael Petullo <mike@flyn.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef _GNU_SOURCE
  21 #define _GNU_SOURCE 1
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <ctype.h>
  30
  31 #include "libvolume_id.h"
  32 #include "libvolume_id-private.h"
  33
  34 #define SECTOR_SHIFT                    9
  35 #define SECTOR_SIZE                     (1 << SECTOR_SHIFT)
  36
  37 #define LUKS_CIPHERNAME_L               32
  38 #define LUKS_CIPHERMODE_L               32
  39 #define LUKS_HASHSPEC_L                 32
  40 #define LUKS_DIGESTSIZE                 20
  41 #define LUKS_SALTSIZE                   32
  42 #define LUKS_NUMKEYS                    8
  43
  44 #define LUKS_MAGIC_L                    6
  45 #define LUKS_PHDR_SIZE                  (sizeof(struct luks_phdr)/SECTOR_SIZE+1)
  46 #define UUID_STRING_L                   40
  47 static const uint8_t LUKS_MAGIC[] = {'L','U','K','S', 0xba, 0xbe};
  48
  49 struct luks_phdr {
  50         uint8_t         magic[LUKS_MAGIC_L];
  51         uint16_t        version;
  52         uint8_t         cipherName[LUKS_CIPHERNAME_L];
  53         uint8_t         cipherMode[LUKS_CIPHERMODE_L];
  54         uint8_t         hashSpec[LUKS_HASHSPEC_L];
  55         uint32_t        payloadOffset;
  56         uint32_t        keyBytes;
  57         uint8_t         mkDigest[LUKS_DIGESTSIZE];
  58         uint8_t         mkDigestSalt[LUKS_SALTSIZE];
  59         uint32_t        mkDigestIterations;
  60         uint8_t         uuid[UUID_STRING_L];
  61         struct {
  62                 uint32_t        active;
  63                 uint32_t        passwordIterations;
  64                 uint8_t         passwordSalt[LUKS_SALTSIZE];
  65                 uint32_t        keyMaterialOffset;
  66                 uint32_t        stripes;
  67         } keyblock[LUKS_NUMKEYS];
  68 };
  69
  70 int volume_id_probe_luks(struct volume_id *id, uint64_t off, uint64_t size)
  71 {
  72         struct luks_phdr *header;
  73
  74         header = (struct luks_phdr*) volume_id_get_buffer(id, off, LUKS_PHDR_SIZE);
  75         if (header == NULL)
  76                 return -1;
  77
  78         if (memcmp(header->magic, LUKS_MAGIC, LUKS_MAGIC_L))
  79                 return -1;
  80
  81         volume_id_set_usage(id, VOLUME_ID_CRYPTO);
  82         volume_id_set_uuid(id, header->uuid, 36, UUID_HEX_STRING);
  83         snprintf(id->type_version, sizeof(header->version), "%u", le16_to_cpu(header->version));
  84         id->type = "crypto_LUKS";
  85         return 0;
  86 }