busybox/util-linux/volume_id/luks.c

/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2005 W. Michael Petullo <mike@flyn.org>
 *
 *	This library is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU Lesser General Public
 *	License as published by the Free Software Foundation; either
 *	version 2.1 of the License, or (at your option) any later version.
 *
 *	This library is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *	Lesser General Public License for more details.
 *
 *	You should have received a copy of the GNU Lesser General Public
 *	License along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
//config:config FEATURE_VOLUMEID_LUKS
//config:	bool "luks filesystem"
//config:	default y
//config:	depends on VOLUMEID

//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_LUKS) += luks.o

#include "volume_id_internal.h"

#define LUKS_MAGIC_L             6
#define UUID_STRING_L           40
#define LUKS_CIPHERNAME_L       32
#define LUKS_CIPHERMODE_L       32
#define LUKS_HASHSPEC_L         32
#define LUKS_DIGESTSIZE         20
#define LUKS_SALTSIZE           32
#define LUKS_NUMKEYS             8

static const uint8_t LUKS_MAGIC[] ALIGN1 = { 'L','U','K','S', 0xba, 0xbe };

struct luks_phdr {
	uint8_t		magic[LUKS_MAGIC_L];
	uint16_t	version;
	uint8_t		cipherName[LUKS_CIPHERNAME_L];
	uint8_t		cipherMode[LUKS_CIPHERMODE_L];
	uint8_t		hashSpec[LUKS_HASHSPEC_L];
	uint32_t	payloadOffset;
	uint32_t	keyBytes;
	uint8_t		mkDigest[LUKS_DIGESTSIZE];
	uint8_t		mkDigestSalt[LUKS_SALTSIZE];
	uint32_t	mkDigestIterations;
	uint8_t		uuid[UUID_STRING_L];
	struct {
		uint32_t	active;
		uint32_t	passwordIterations;
		uint8_t		passwordSalt[LUKS_SALTSIZE];
		uint32_t	keyMaterialOffset;
		uint32_t	stripes;
	} keyblock[LUKS_NUMKEYS];
};

enum {
	EXPECTED_SIZE_luks_phdr = 0
		+ 1 * LUKS_MAGIC_L
		+ 2
		+ 1 * LUKS_CIPHERNAME_L
		+ 1 * LUKS_CIPHERMODE_L
		+ 1 * LUKS_HASHSPEC_L
		+ 4
		+ 4
		+ 1 * LUKS_DIGESTSIZE
		+ 1 * LUKS_SALTSIZE
		+ 4
		+ 1 * UUID_STRING_L
		+ LUKS_NUMKEYS * (0
		  + 4
		  + 4
		  + 1 * LUKS_SALTSIZE
		  + 4
		  + 4
		  )
};

struct BUG_bad_size_luks_phdr {
	char BUG_bad_size_luks_phdr[
		sizeof(struct luks_phdr) == EXPECTED_SIZE_luks_phdr ?
		1 : -1];
};

int FAST_FUNC volume_id_probe_luks(struct volume_id *id /*,uint64_t off*/)
{
#define off ((uint64_t)0)
	struct luks_phdr *header;

	header = volume_id_get_buffer(id, off, sizeof(*header));
	if (header == NULL)
		return -1;

	if (memcmp(header->magic, LUKS_MAGIC, LUKS_MAGIC_L))
		return -1;

//	volume_id_set_usage(id, VOLUME_ID_CRYPTO);
	volume_id_set_uuid(id, header->uuid, UUID_DCE_STRING);
	IF_FEATURE_BLKID_TYPE(id->type = "crypto_LUKS";)

	return 0;
}