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/*
* LUKS - Linux Unified Key Setup
*
* Copyright (C) 2004-2006, Clemens Fruhwirth <clemens@endorphin.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include "luks.h"
#include "../lib/libcryptsetup.h"
#include "../lib/internal.h"
#include "../lib/blockdev.h"
#define div_round_up(a,b) ({ \
typeof(a) __a = (a); \
typeof(b) __b = (b); \
(__a - 1) / __b + 1; \
})
static int setup_mapping(const char *cipher, const char *name,
const char *device, unsigned int payloadOffset,
const char *key, size_t keyLength,
unsigned int sector, size_t srcLength,
struct setup_backend *backend,
int mode)
{
struct crypt_options k;
struct crypt_options *options = &k;
int device_sector_size = sector_size_for_device(device);
int r;
/*
* we need to round this to nearest multiple of the underlying
* device's sector size, otherwise the mapping will be refused.
*/
if(device_sector_size < 0) {
fprintf(stderr,_("Unable to obtain sector size for %s"),device);
return -EINVAL;
}
options->size = round_up_modulo(srcLength,device_sector_size)/SECTOR_SIZE;
options->offset = sector;
options->cipher = cipher;
options->key_size = keyLength;
options->skip = 0;
options->flags = 0;
options->name = name;
options->device = device;
if (mode == O_RDONLY) {
options->flags |= CRYPT_FLAG_READONLY;
}
r = backend->create(0, options, key);
if (r <= 0)
set_error(NULL);
return r;
}
static int clear_mapping(const char *name, struct setup_backend *backend)
{
struct crypt_options options;
options.name=name;
return backend->remove(&options);
}
static int LUKS_endec_template(char *src, size_t srcLength,
struct luks_phdr *hdr,
char *key, size_t keyLength,
const char *device,
unsigned int sector, struct setup_backend *backend,
ssize_t (*func)(int, void *, size_t),
int mode)
{
int devfd;
char *name = NULL;
char *fullpath = NULL;
char *dmCipherSpec = NULL;
const char *dmDir = backend->dir();
int r = -1;
if(dmDir == NULL) {
fputs(_("Failed to obtain device mapper directory."), stderr);
return -1;
}
if(asprintf(&name,"temporary-cryptsetup-%d",getpid()) == -1 ||
asprintf(&fullpath,"%s/%s",dmDir,name) == -1 ||
asprintf(&dmCipherSpec,"%s-%s",hdr->cipherName, hdr->cipherMode) == -1) {
r = -ENOMEM;
goto out1;
}
r = setup_mapping(dmCipherSpec,name,device,hdr->payloadOffset,key,keyLength,sector,srcLength,backend,mode);
if(r < 0) {
fprintf(stderr,"Failed to setup dm-crypt key mapping.\nCheck kernel for support for the %s cipher spec and verify that %s contains at least %d sectors.\n",
dmCipherSpec,
device,
sector + div_round_up(srcLength,SECTOR_SIZE));
r = -EIO;
goto out1;
}
devfd = open(fullpath, mode | O_DIRECT | O_SYNC);
if(devfd == -1) { r = -EIO; goto out2; }
r = func(devfd,src,srcLength);
if(r < 0) { r = -EIO; goto out3; }
r = 0;
out3:
close(devfd);
out2:
clear_mapping(name,backend);
out1:
free(dmCipherSpec);
free(fullpath);
free(name);
return r;
}
int LUKS_encrypt_to_storage(char *src, size_t srcLength,
struct luks_phdr *hdr,
char *key, size_t keyLength,
const char *device,
unsigned int sector, struct setup_backend *backend)
{
return LUKS_endec_template(src,srcLength,hdr,key,keyLength, device, sector, backend,
(ssize_t (*)(int, void *, size_t)) write_blockwise, O_RDWR);
}
int LUKS_decrypt_from_storage(char *dst, size_t dstLength,
struct luks_phdr *hdr,
char *key, size_t keyLength,
const char *device,
unsigned int sector, struct setup_backend *backend)
{
return LUKS_endec_template(dst,dstLength,hdr,key,keyLength, device, sector, backend, read_blockwise, O_RDONLY);
}
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