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 it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  */
  10
  11 #ifndef _GNU_SOURCE
  12 #define _GNU_SOURCE 1
  13 #endif
  14
  15 #ifdef HAVE_CONFIG_H
  16 #  include <config.h>
  17 #endif
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25
  26 #include "libvolume_id.h"
  27 #include "libvolume_id-private.h"
  28 #include "util.h"
  29
  30 #define SECTOR_SHIFT                    9
  31 #define SECTOR_SIZE                     (1 << SECTOR_SHIFT)
  32
  33 #define LUKS_CIPHERNAME_L               32
  34 #define LUKS_CIPHERMODE_L               32
  35 #define LUKS_HASHSPEC_L                 32
  36 #define LUKS_DIGESTSIZE                 20
  37 #define LUKS_SALTSIZE                   32
  38 #define LUKS_NUMKEYS                    8
  39
  40 #define LUKS_MAGIC_L                    6
  41 #define LUKS_PHDR_SIZE                  (sizeof(struct luks_phdr)/SECTOR_SIZE+1)
  42 #define UUID_STRING_L                   40
  43 static const uint8_t LUKS_MAGIC[] = {'L','U','K','S', 0xba, 0xbe};
  44
  45 struct luks_phdr {
  46         uint8_t         magic[LUKS_MAGIC_L];
  47         uint16_t        version;
  48         uint8_t         cipherName[LUKS_CIPHERNAME_L];
  49         uint8_t         cipherMode[LUKS_CIPHERMODE_L];
  50         uint8_t         hashSpec[LUKS_HASHSPEC_L];
  51         uint32_t        payloadOffset;
  52         uint32_t        keyBytes;
  53         uint8_t         mkDigest[LUKS_DIGESTSIZE];
  54         uint8_t         mkDigestSalt[LUKS_SALTSIZE];
  55         uint32_t        mkDigestIterations;
  56         uint8_t         uuid[UUID_STRING_L];
  57         struct {
  58                 uint32_t        active;
  59                 uint32_t        passwordIterations;
  60                 uint8_t         passwordSalt[LUKS_SALTSIZE];
  61                 uint32_t        keyMaterialOffset;
  62                 uint32_t        stripes;
  63         } keyblock[LUKS_NUMKEYS];
  64 };
  65
  66 int volume_id_probe_luks(struct volume_id *id, uint64_t off, uint64_t size)
  67 {
  68         struct luks_phdr *header;
  69
  70         header = (struct luks_phdr*) volume_id_get_buffer(id, off, LUKS_PHDR_SIZE);
  71         if (header == NULL)
  72                 return -1;
  73
  74         if (memcmp(header->magic, LUKS_MAGIC, LUKS_MAGIC_L))
  75                 return -1;
  76
  77         volume_id_set_usage(id, VOLUME_ID_CRYPTO);
  78         volume_id_set_uuid(id, header->uuid, 36, UUID_HEX_STRING);
  79         snprintf(id->type_version, sizeof(header->version), "%u", le16_to_cpu(header->version));
  80         id->type = "crypto_LUKS";
  81         return 0;
  82 }