extras/volume_id/volume_id/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 library is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU Lesser General Public
   8  *      License as published by the Free Software Foundation; either
   9  *      version 2.1 of the License, or (at your option) any later version.
  10  *
  11  *      This library 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 GNU
  14  *      Lesser General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU Lesser General Public
  17  *      License along with this library; if not, write to the Free Software
  18  *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  */
  20
  21 #ifndef _GNU_SOURCE
  22 #define _GNU_SOURCE 1
  23 #endif
  24
  25 #ifdef HAVE_CONFIG_H
  26 #  include <config.h>
  27 #endif
  28
  29 #include <netinet/in.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33 #include <string.h>
  34 #include <errno.h>
  35 #include <ctype.h>
  36 #include <asm/types.h>
  37
  38 #include "volume_id.h"
  39 #include "util.h"
  40 #include "logging.h"
  41 #include "luks.h"
  42
  43 /* from cryptsetup-luks internal.h */
  44 #define SECTOR_SHIFT            9
  45 #define SECTOR_SIZE             (1 << SECTOR_SHIFT)
  46
  47 /* from cryptsetup-luks luks.h */
  48 #define LUKS_CIPHERNAME_L 32
  49 #define LUKS_CIPHERMODE_L 32
  50 #define LUKS_HASHSPEC_L 32
  51 #define LUKS_DIGESTSIZE 20 /* since SHA1 */
  52 #define LUKS_SALTSIZE 32
  53 #define LUKS_NUMKEYS 8
  54
  55 /* from cryptsetup-luks luks.h */
  56 const unsigned char LUKS_MAGIC[] = {'L','U','K','S', 0xba, 0xbe};
  57 #define LUKS_MAGIC_L 6
  58
  59 /* from cryptsetup-luks luks.h */
  60 #define LUKS_PHDR_SIZE (sizeof(struct luks_phdr)/SECTOR_SIZE+1)
  61
  62 /* from cryptsetup-luks luks.h */
  63 #define UUID_STRING_L 40
  64
  65 int volume_id_probe_luks(struct volume_id *id, __u64 off)
  66 {
  67         /* from cryptsetup-luks luks.h */
  68         struct luks_phdr {
  69                 char            magic[LUKS_MAGIC_L];
  70                 uint16_t        version;
  71                 char            cipherName[LUKS_CIPHERNAME_L];
  72                 char            cipherMode[LUKS_CIPHERMODE_L];
  73                 char            hashSpec[LUKS_HASHSPEC_L];
  74                 uint32_t        payloadOffset;
  75                 uint32_t        keyBytes;
  76                 char            mkDigest[LUKS_DIGESTSIZE];
  77                 char            mkDigestSalt[LUKS_SALTSIZE];
  78                 uint32_t        mkDigestIterations;
  79                 char            uuid[UUID_STRING_L];
  80                 struct {
  81                         uint32_t active;
  82
  83                         /* parameters used for password processing */
  84                         uint32_t passwordIterations;
  85                         char     passwordSalt[LUKS_SALTSIZE];
  86
  87                         /* parameters used for AF store/load */
  88                         uint32_t keyMaterialOffset;
  89                         uint32_t stripes;
  90                 } keyblock[LUKS_NUMKEYS];
  91         } *header;
  92
  93         header = (struct luks_phdr*) volume_id_get_buffer(id, off, LUKS_PHDR_SIZE);
  94
  95         if (header == NULL)
  96                 return -1;
  97
  98         if (memcmp(header->magic, LUKS_MAGIC, LUKS_MAGIC_L))
  99                 return -1;
 100
 101         volume_id_set_usage(id, VOLUME_ID_CRYPTO);
 102         volume_id_set_uuid(id, header->uuid, UUID_DCE);
 103         id->type = "crypto_LUKS";
 104
 105         return 0;
 106 }