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gnupg/g13/sh-dmcrypt.c

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/* sh-dmcrypt.c - The DM-Crypt part for g13-syshelp
* Copyright (C) 2015, 2016 Werner Koch
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include <assert.h>
#include <sys/types.h>
#ifdef HAVE_SYS_MKDEV_H
#include <sys/mkdev.h>
#endif
#ifdef HAVE_SYS_SYSMACROS_H
# include <sys/sysmacros.h>
#endif
#ifdef HAVE_STAT
# include <sys/stat.h>
#endif
#include <unistd.h>
#include "g13-syshelp.h"
#include <assuan.h>
#include "../common/i18n.h"
#include "g13tuple.h"
#include "../common/exectool.h"
#include "../common/sysutils.h"
#include "keyblob.h"
/* The standard disk block size (logical). */
#define SECTOR_SIZE 512
/* The physical block size used by modern devices. */
#define PHY_SECTOR_SIZE (SECTOR_SIZE*8) /* 4 KiB */
/* The length of the crypto setup area in sectors. 16 KiB is a nice
multiple of a modern block size and should be sufficient for all
kind of extra public key encryption packets. */
#define SETUP_AREA_SECTORS 32 /* 16 KiB */
/* The number of header block copies stored at the begin and end of
the device. */
#define HEADER_SETUP_AREA_COPIES 2
#define FOOTER_SETUP_AREA_COPIES 2
/* The length in blocks of the space we put at the start and at the
end of the device. This space is used to store N copies of the
setup area for the actual encrypted container in between. */
#define HEADER_SECTORS (SETUP_AREA_SECTORS * HEADER_SETUP_AREA_COPIES)
#define FOOTER_SECTORS (SETUP_AREA_SECTORS * FOOTER_SETUP_AREA_COPIES)
/* Minimim size of the encrypted space in blocks. This is more or
less an arbitrary value. */
#define MIN_ENCRYPTED_SPACE 32
/* Some consistency checks for the above constants. */
#if (PHY_SECTOR_SIZE % SECTOR_SIZE)
# error the physical secotor size should be a multiple of 512
#endif
#if ((SETUP_AREA_SECTORS*SECTOR_SIZE) % PHY_SECTOR_SIZE)
# error The setup area size should be a multiple of the phy. sector size.
#endif
/*
* Check whether the block device DEVNAME is used by device mapper.
* If EXPECT_BUSY is set no error message is printed if the device is
* busy. Returns: 0 if the device is good and not yet used by DM.
*/
static gpg_error_t
check_blockdev (const char *devname, int expect_busy)
{
gpg_error_t err;
struct stat sb;
unsigned int devmajor, devminor;
char *result = NULL;
char **lines = NULL;
char **fields = NULL;
int lno, count;
if (gnupg_stat (devname, &sb))
{
err = gpg_error_from_syserror ();
log_error ("error stating '%s': %s\n", devname, gpg_strerror (err));
return err;
}
if (!S_ISBLK (sb.st_mode))
{
err = gpg_error (GPG_ERR_ENOTBLK);
log_error ("can't use '%s': %s\n", devname, gpg_strerror (err));
return err;
}
devmajor = major (sb.st_rdev);
devminor = minor (sb.st_rdev);
{
const char *argv[2];
argv[0] = "deps";
argv[1] = NULL;
err = gnupg_exec_tool ("/sbin/dmsetup", argv, NULL, &result, NULL);
}
if (err)
{
log_error ("error running '%s' to search for '%s': %s\n",
"dmsetup deps", devname, gpg_strerror (err));
goto leave;
}
lines = strsplit (result, '\n', 0, NULL);
if (!lines)
{
err = gpg_error_from_syserror ();
goto leave;
}
if (lines[0] && !strcmp (lines[0], "No devices found"))
;
else
{
for (lno=0; lines[lno]; lno++)
{
unsigned int xmajor, xminor;
if (!*lines[lno])
continue;
xfree (fields);
fields = strsplit (lines[lno], ':', 0, &count);
if (!fields)
{
err = gpg_error_from_syserror ();
goto leave;
}
if (count < 3
|| sscanf (fields[2], " (%u,%u)", &xmajor, &xminor) != 2)
{
log_error ("error running '%s' to search for '%s': %s\n",
"dmsetup deps", devname, "unexpected output");
err = gpg_error (GPG_ERR_INV_VALUE);
goto leave;
}
if (xmajor == devmajor && xminor == devminor)
{
if (!expect_busy)
log_error ("device '%s' (%u:%u)"
" already in use by device mapper\n",
devname, devmajor, devminor);
err = gpg_error (GPG_ERR_EBUSY);
goto leave;
}
}
}
leave:
xfree (fields);
xfree (lines);
xfree (result);
return err;
}
/* Return a malloced buffer with the prefix of the setup area. This
is the data written right before the encrypted keyblob. Return NULL
on error and sets ERRNO. */
static void *
mk_setup_area_prefix (size_t *r_length)
{
unsigned char *packet;
size_t setuparealen;
packet = xtrymalloc (32);
if (!packet)
return NULL;
*r_length = 32;
setuparealen = SETUP_AREA_SECTORS * SECTOR_SIZE;
packet[0] = (0xc0|61); /* CTB for the private packet type 0x61. */
packet[1] = 0xff; /* 5 byte length packet, value 20. */
packet[2] = 0;
packet[3] = 0;
packet[4] = 0;
packet[5] = 26;
memcpy (packet+6, "GnuPG/G13", 10); /* Packet subtype. */
packet[16] = 1; /* G13 packet format version. */
packet[17] = 0; /* Reserved. */
packet[18] = 0; /* Reserved. */
packet[19] = 1; /* OS Flag = Linux */
packet[20] = (setuparealen >> 24); /* Total length of header. */
packet[21] = (setuparealen >> 16);
packet[22] = (setuparealen >> 8);
packet[23] = (setuparealen);
packet[24] = HEADER_SETUP_AREA_COPIES;
packet[25] = FOOTER_SETUP_AREA_COPIES;
packet[26] = 0; /* Reserved. */
packet[27] = 0; /* Reserved. */
packet[28] = 0; /* Reserved. */
packet[29] = 0; /* Reserved. */
packet[30] = 0; /* Reserved. */
packet[31] = 0; /* Reserved. */
return packet;
}
/* Create a new g13 styloe DM-Crypt container on devoce DEVNAME. */
gpg_error_t
sh_dmcrypt_create_container (ctrl_t ctrl, const char *devname, estream_t devfp)
{
gpg_error_t err;
char *header_space;
size_t header_space_size, header_space_used;
size_t paddinglen;
char *targetname = NULL;
size_t nread;
char *p;
char hexkey[16*2+1];
char *table = NULL;
unsigned long long nblocks;
char *result = NULL;
unsigned char twobyte[2];
membuf_t keyblob;
void *keyblob_buf = NULL;
size_t keyblob_len;
size_t n;
const char *s;
unsigned char *packet;
int copy;
if (!ctrl->devti)
return gpg_error (GPG_ERR_INV_ARG);
g13_syshelp_i_know_what_i_am_doing ();
header_space_size = SETUP_AREA_SECTORS * SECTOR_SIZE;
header_space = xtrymalloc (header_space_size);
if (!header_space)
return gpg_error_from_syserror ();
/* Start building the keyblob. */
init_membuf (&keyblob, 512);
append_tuple (&keyblob, KEYBLOB_TAG_BLOBVERSION, "\x01", 1);
n = CONTTYPE_DM_CRYPT;
twobyte[0] = (n >> 8);
twobyte[1] = n;
append_tuple (&keyblob, KEYBLOB_TAG_CONTTYPE, twobyte, 2);
{
gnupg_isotime_t tbuf;
gnupg_get_isotime (tbuf);
append_tuple (&keyblob, KEYBLOB_TAG_CREATED, tbuf, strlen (tbuf));
}
/* Rewind device stream. */
if (es_fseeko (devfp, 0, SEEK_SET))
{
err = gpg_error_from_syserror ();
log_error ("error seeking to begin of '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
es_clearerr (devfp);
/* Extra check that the device is empty. */
if (es_read (devfp, header_space, header_space_size, &nread))
err = gpg_error_from_syserror ();
else if (nread != header_space_size)
err = gpg_error (GPG_ERR_TOO_SHORT);
else
err = 0;
if (err)
{
log_error ("error reading header space of '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
for (p=header_space; nread && !*p; nread--, p++)
;
if (nread)
{
log_error ("header space of '%s' already used - use %s to override\n",
devname, "--force");
err = gpg_error (GPG_ERR_NOT_SUPPORTED);
goto leave;
}
/* Check that the device is not used by device mapper. */
err = check_blockdev (devname, 0);
if (err)
goto leave;
/* Compute the number of blocks. */
err = sh_blockdev_getsz (devname, &nblocks);
if (err)
{
log_error ("error getting size of '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
if (nblocks <= HEADER_SECTORS + MIN_ENCRYPTED_SPACE + FOOTER_SECTORS)
{
log_error ("device '%s' is too small (min=%d blocks)\n",
devname,
HEADER_SECTORS + MIN_ENCRYPTED_SPACE + FOOTER_SECTORS);
err = gpg_error (GPG_ERR_TOO_SHORT);
goto leave;
}
append_tuple_uint (&keyblob, KEYBLOB_TAG_CONT_NSEC, nblocks);
nblocks -= HEADER_SECTORS + FOOTER_SECTORS;
append_tuple_uint (&keyblob, KEYBLOB_TAG_ENC_NSEC, nblocks);
append_tuple_uint (&keyblob, KEYBLOB_TAG_ENC_OFF, HEADER_SECTORS);
/* Device mapper needs a name for the device: Take it from the label
or use "0". */
targetname = strconcat ("g13-", ctrl->client.uname, "-",
ctrl->devti->label? ctrl->devti->label : "0",
NULL);
if (!targetname)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Create the key. */
{
char key[16];
gcry_randomize (key, sizeof key, GCRY_STRONG_RANDOM);
append_tuple (&keyblob, KEYBLOB_TAG_ENCKEY, key, sizeof key);
bin2hex (key, 16, hexkey);
wipememory (key, 16);
/* Add a 2*(4+16) byte filler to conceal the fact that we use
AES-128. If we ever want to switch to 256 bit we can resize
that filler to keep the keyblob at the same size. */
append_tuple (&keyblob, KEYBLOB_TAG_FILLER, key, sizeof key);
append_tuple (&keyblob, KEYBLOB_TAG_FILLER, key, sizeof key);
}
/* Build dmcrypt table. */
s = "aes-cbc-essiv:sha256";
append_tuple (&keyblob, KEYBLOB_TAG_ALGOSTR, s, strlen (s));
table = es_bsprintf ("0 %llu crypt %s %s 0 %s %d",
nblocks, s, hexkey, devname, HEADER_SECTORS);
if (!table)
{
err = gpg_error_from_syserror ();
goto leave;
}
wipememory (hexkey, sizeof hexkey);
/* Add a copy of the setup area prefix to the keyblob. */
p = mk_setup_area_prefix (&n);
if (!p)
{
err = gpg_error_from_syserror ();
goto leave;
}
append_tuple (&keyblob, KEYBLOB_TAG_HDRCOPY, p, n);
assert (n < header_space_size);
memcpy (header_space, p, n);
header_space_used = n;
/* Turn the keyblob into a buffer and callback to encrypt it. */
keyblob_buf = get_membuf (&keyblob, &keyblob_len);
if (!keyblob_buf)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = sh_encrypt_keyblob (ctrl, keyblob_buf, keyblob_len, &p, &n);
if (err)
{
log_error ("encrypting the keyblob failed: %s\n", gpg_strerror (err));
goto leave;
}
log_debug ("plain setuparea=%p %zu bytes\n", keyblob_buf, keyblob_len);
wipememory (keyblob_buf, keyblob_len);
xfree (keyblob_buf);
keyblob_buf = NULL;
log_debug ("encry setuparea=%p %zu bytes\n", p, n);
if (n >= header_space_size || (header_space_used + n) >= header_space_size)
{
err = gpg_error (GPG_ERR_TOO_LARGE);
log_error ("setup area would overflow: %s\n", gpg_strerror (err));
goto leave;
}
memcpy (header_space + header_space_used, p, n);
header_space_used += n;
/* Write the padding. */
packet = header_space + header_space_used;
paddinglen = header_space_size - header_space_used;
if (paddinglen < 16)
{
err = gpg_error (GPG_ERR_TOO_LARGE);
log_error ("setup area too short for padding: %s\n", gpg_strerror (err));
goto leave;
}
packet[0] = (0xc0|61); /* CTB for Private packet type 0x61. */
packet[1] = 0xff; /* 5 byte length packet, value 20. */
packet[2] = (paddinglen-6) >> 24;
packet[3] = (paddinglen-6) >> 16;
packet[4] = (paddinglen-6) >> 8;
packet[5] = (paddinglen-6);
packet += 6;
paddinglen -= 6;
header_space_used += 6;
for ( ;paddinglen >= 10;
paddinglen -= 10, packet += 10, header_space_used += 10)
memcpy (packet, "GnuPG/PAD", 10);
for ( ;paddinglen; paddinglen--, packet++, header_space_used++)
*packet = 0;
if (header_space_used != header_space_size)
BUG ();
/* Create the container. */
{
const char *argv[3];
argv[0] = "create";
argv[1] = targetname;
argv[2] = NULL;
log_debug ("now running \"dmsetup create %s\"\n", targetname);
log_debug (" with table='%s'\"\n", table);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, table, &result, NULL);
}
if (err)
{
log_error ("error running dmsetup for '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
/* Write the setup area. */
if (es_fseeko (devfp, 0, SEEK_SET))
{
err = gpg_error_from_syserror ();
log_error ("error seeking to begin of '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
es_clearerr (devfp);
for (copy = 0; copy < HEADER_SETUP_AREA_COPIES; copy++)
{
size_t nwritten;
if (es_write (devfp, header_space, header_space_size, &nwritten))
{
err = gpg_error_from_syserror ();
break;
}
else if (nwritten != header_space_size)
{
err = gpg_error (GPG_ERR_TOO_SHORT);
break;
}
}
if (err)
{
log_error ("error writing header space copy %d of '%s': %s\n",
copy, devname, gpg_strerror (err));
goto leave;
}
if (es_fseeko (devfp,
(- header_space_size * FOOTER_SETUP_AREA_COPIES), SEEK_END))
{
err = gpg_error_from_syserror ();
log_error ("error seeking to end of '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
es_clearerr (devfp);
for (copy = 0; copy < FOOTER_SETUP_AREA_COPIES; copy++)
{
size_t nwritten;
if (es_write (devfp, header_space, header_space_size, &nwritten))
{
err = gpg_error_from_syserror ();
break;
}
else if (nwritten != header_space_size)
{
err = gpg_error (GPG_ERR_TOO_SHORT);
break;
}
}
if (!err && es_fflush (devfp))
err = gpg_error_from_syserror ();
if (err)
{
log_error ("error writing footer space copy %d of '%s': %s\n",
copy, devname, gpg_strerror (err));
goto leave;
}
leave:
wipememory (hexkey, sizeof hexkey);
if (table)
{
wipememory (table, strlen (table));
xfree (table);
}
if (keyblob_buf)
{
wipememory (keyblob_buf, keyblob_len);
xfree (keyblob_buf);
}
xfree (get_membuf (&keyblob, NULL));
xfree (targetname);
xfree (result);
xfree (header_space);
return err;
}
/* Mount a DM-Crypt container on device DEVNAME taking keys and other
* meta data from KEYBLOB. */
gpg_error_t
sh_dmcrypt_mount_container (ctrl_t ctrl, const char *devname,
tupledesc_t keyblob)
{
gpg_error_t err;
char *targetname_abs = NULL;
const char *targetname;
char hexkey[16*2+1];
char *table = NULL;
unsigned long long nblocks, nblocks2;
char *result = NULL;
size_t n;
const char *s;
const char *algostr;
size_t algostrlen;
if (!ctrl->devti)
return gpg_error (GPG_ERR_INV_ARG);
g13_syshelp_i_know_what_i_am_doing ();
/* Check that the device is not yet used by device mapper. */
err = check_blockdev (devname, 0);
if (err)
goto leave;
/* Compute the number of blocks and compare them to the value
provided as meta data. */
err = sh_blockdev_getsz (devname, &nblocks);
if (err)
{
log_error ("error getting size of '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
err = find_tuple_uint (keyblob, KEYBLOB_TAG_CONT_NSEC, &nblocks2);
if (err)
{
log_error ("error getting size from keyblob: %s\n", gpg_strerror (err));
goto leave;
}
if (nblocks != nblocks2)
{
log_error ("inconsistent size of container: expected==%llu got=%llu\n",
nblocks2, nblocks);
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
if (nblocks <= HEADER_SECTORS + MIN_ENCRYPTED_SPACE + FOOTER_SECTORS)
{
log_error ("device '%s' is too small (min=%d blocks)\n",
devname,
HEADER_SECTORS + MIN_ENCRYPTED_SPACE + FOOTER_SECTORS);
err = gpg_error (GPG_ERR_TOO_SHORT);
goto leave;
}
nblocks -= HEADER_SECTORS + FOOTER_SECTORS;
err = find_tuple_uint (keyblob, KEYBLOB_TAG_ENC_NSEC, &nblocks2);
if (err)
{
log_error ("error getting enc size from keyblob: %s\n",
gpg_strerror (err));
goto leave;
}
if (nblocks != nblocks2)
{
log_error ("inconsistent size of enc data: expected==%llu got=%llu\n",
nblocks2, nblocks);
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
/* Check that the offset is consistent. */
err = find_tuple_uint (keyblob, KEYBLOB_TAG_ENC_OFF, &nblocks2);
if (err)
{
log_error ("error getting enc offset from keyblob: %s\n",
gpg_strerror (err));
goto leave;
}
if (nblocks2 != HEADER_SECTORS)
{
log_error ("inconsistent offset of enc data: expected==%llu got=%d\n",
nblocks2, HEADER_SECTORS);
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
/* Device mapper needs a name for the device: Take it from the label
or use "0". */
targetname_abs = strconcat ("/dev/mapper/",
"g13-", ctrl->client.uname, "-",
ctrl->devti->label? ctrl->devti->label : "0",
NULL);
if (!targetname_abs)
{
err = gpg_error_from_syserror ();
goto leave;
}
targetname = strrchr (targetname_abs, '/');
if (!targetname)
BUG ();
targetname++;
/* Get the algorithm string. */
algostr = find_tuple (keyblob, KEYBLOB_TAG_ALGOSTR, &algostrlen);
if (!algostr || algostrlen > 100)
{
log_error ("algo string not found in keyblob or too long\n");
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
/* Get the key. */
s = find_tuple (keyblob, KEYBLOB_TAG_ENCKEY, &n);
if (!s || n != 16)
{
if (!s)
log_error ("no key found in keyblob\n");
else
log_error ("unexpected size of key (%zu)\n", n);
err = gpg_error (GPG_ERR_INV_KEYLEN);
goto leave;
}
bin2hex (s, 16, hexkey);
/* Build dmcrypt table. */
table = es_bsprintf ("0 %llu crypt %.*s %s 0 %s %d",
nblocks, (int)algostrlen, algostr,
hexkey, devname, HEADER_SECTORS);
wipememory (hexkey, sizeof hexkey);
if (!table)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Load the table. */
{
const char *argv[3];
argv[0] = "create";
argv[1] = targetname;
argv[2] = NULL;
log_debug ("now running \"dmsetup create %s\"\n", targetname);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, table, &result, NULL);
}
if (err)
{
log_error ("error running dmsetup for '%s': %s\n",
devname, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
xfree (result);
result = NULL;
/* Mount if a mountpoint has been given. */
if (ctrl->devti->mountpoint)
{
const char *argv[3];
argv[0] = targetname_abs;
argv[1] = ctrl->devti->mountpoint;
argv[2] = NULL;
log_debug ("now running \"mount %s %s\"\n",
targetname_abs, ctrl->devti->mountpoint);
err = gnupg_exec_tool ("/bin/mount", argv, NULL, &result, NULL);
if (err)
{
log_error ("error running mount: %s\n", gpg_strerror (err));
goto leave;
}
if (result && *result) /* (We should not see output to stdout). */
log_info ("WARNING: mount returned data on stdout! (%s)\n", result);
}
leave:
wipememory (hexkey, sizeof hexkey);
if (table)
{
wipememory (table, strlen (table));
xfree (table);
}
xfree (targetname_abs);
xfree (result);
return err;
}
/* Unmount a DM-Crypt container on device DEVNAME and wipe the keys. */
gpg_error_t
sh_dmcrypt_umount_container (ctrl_t ctrl, const char *devname)
{
gpg_error_t err;
char *targetname_abs = NULL;
char *result = NULL;
if (!ctrl->devti)
return gpg_error (GPG_ERR_INV_ARG);
g13_syshelp_i_know_what_i_am_doing ();
/* Check that the device is used by device mapper. */
err = check_blockdev (devname, 1);
if (gpg_err_code (err) != GPG_ERR_EBUSY)
{
log_error ("device '%s' is not used by the device mapper: %s\n",
devname, gpg_strerror (err));
goto leave;
}
/* Fixme: Check that this is really a g13 partition. */
/* Device mapper needs a name for the device: Take it from the label
or use "0". */
targetname_abs = strconcat ("/dev/mapper/",
"g13-", ctrl->client.uname, "-",
ctrl->devti->label? ctrl->devti->label : "0",
NULL);
if (!targetname_abs)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Run the regular umount command. */
{
const char *argv[2];
argv[0] = targetname_abs;
argv[1] = NULL;
log_debug ("now running \"umount %s\"\n", targetname_abs);
err = gnupg_exec_tool ("/bin/umount", argv, NULL, &result, NULL);
}
if (err)
{
log_error ("error running umount: %s\n", gpg_strerror (err));
if (1)
{
/* Try to show some info about processes using the partition. */
const char *argv[3];
argv[0] = "-mv";
argv[1] = targetname_abs;
argv[2] = NULL;
gnupg_exec_tool ("/bin/fuser", argv, NULL, &result, NULL);
}
goto leave;
}
if (result && *result) /* (We should not see output to stdout). */
log_info ("WARNING: umount returned data on stdout! (%s)\n", result);
xfree (result);
result = NULL;
/* Run the dmsetup remove command. */
{
const char *argv[3];
argv[0] = "remove";
argv[1] = targetname_abs;
argv[2] = NULL;
log_debug ("now running \"dmsetup remove %s\"\n", targetname_abs);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, NULL, &result, NULL);
}
if (err)
{
log_error ("error running \"dmsetup remove %s\": %s\n",
targetname_abs, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
xfree (result);
result = NULL;
leave:
xfree (targetname_abs);
xfree (result);
return err;
}
/* Suspend a DM-Crypt container on device DEVNAME and wipe the keys. */
gpg_error_t
sh_dmcrypt_suspend_container (ctrl_t ctrl, const char *devname)
{
gpg_error_t err;
char *targetname_abs = NULL;
const char *targetname;
char *result = NULL;
if (!ctrl->devti)
return gpg_error (GPG_ERR_INV_ARG);
g13_syshelp_i_know_what_i_am_doing ();
/* Check that the device is used by device mapper. */
err = check_blockdev (devname, 1);
if (gpg_err_code (err) != GPG_ERR_EBUSY)
{
log_error ("device '%s' is not used by the device mapper: %s\n",
devname, gpg_strerror (err));
goto leave;
}
/* Fixme: Check that this is really a g13 partition. */
/* Device mapper needs a name for the device: Take it from the label
or use "0". */
targetname_abs = strconcat ("/dev/mapper/",
"g13-", ctrl->client.uname, "-",
ctrl->devti->label? ctrl->devti->label : "0",
NULL);
if (!targetname_abs)
{
err = gpg_error_from_syserror ();
goto leave;
}
targetname = strrchr (targetname_abs, '/');
if (!targetname)
BUG ();
targetname++;
/* Send the suspend command. */
{
const char *argv[3];
argv[0] = "suspend";
argv[1] = targetname;
argv[2] = NULL;
log_debug ("now running \"dmsetup suspend %s\"\n", targetname);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, NULL, &result, NULL);
}
if (err)
{
log_error ("error running \"dmsetup suspend %s\": %s\n",
targetname, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
xfree (result);
result = NULL;
/* Send the wipe key command. */
{
const char *argv[5];
argv[0] = "message";
argv[1] = targetname;
argv[2] = "0";
argv[3] = "key wipe";
argv[4] = NULL;
log_debug ("now running \"dmsetup message %s 0 key wipe\"\n", targetname);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, NULL, &result, NULL);
}
if (err)
{
log_error ("error running \"dmsetup message %s 0 key wipe\": %s\n",
targetname, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
xfree (result);
result = NULL;
leave:
xfree (targetname_abs);
xfree (result);
return err;
}
/* Resume a DM-Crypt container on device DEVNAME taking keys and other
* meta data from KEYBLOB. */
gpg_error_t
sh_dmcrypt_resume_container (ctrl_t ctrl, const char *devname,
tupledesc_t keyblob)
{
gpg_error_t err;
char *targetname_abs = NULL;
const char *targetname;
char hexkey[8+16*2+1]; /* 8 is used to prepend "key set ". */
char *table = NULL;
char *result = NULL;
size_t n;
const char *s;
const char *algostr;
size_t algostrlen;
if (!ctrl->devti)
return gpg_error (GPG_ERR_INV_ARG);
g13_syshelp_i_know_what_i_am_doing ();
/* Check that the device is used by device mapper. */
err = check_blockdev (devname, 1);
if (gpg_err_code (err) != GPG_ERR_EBUSY)
{
log_error ("device '%s' is not used by the device mapper: %s\n",
devname, gpg_strerror (err));
goto leave;
}
/* Device mapper needs a name for the device: Take it from the label
or use "0". */
targetname_abs = strconcat ("/dev/mapper/",
"g13-", ctrl->client.uname, "-",
ctrl->devti->label? ctrl->devti->label : "0",
NULL);
if (!targetname_abs)
{
err = gpg_error_from_syserror ();
goto leave;
}
targetname = strrchr (targetname_abs, '/');
if (!targetname)
BUG ();
targetname++;
/* Get the algorithm string. */
algostr = find_tuple (keyblob, KEYBLOB_TAG_ALGOSTR, &algostrlen);
if (!algostr || algostrlen > 100)
{
log_error ("algo string not found in keyblob or too long\n");
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
/* Get the key. */
s = find_tuple (keyblob, KEYBLOB_TAG_ENCKEY, &n);
if (!s || n != 16)
{
if (!s)
log_error ("no key found in keyblob\n");
else
log_error ("unexpected size of key (%zu)\n", n);
err = gpg_error (GPG_ERR_INV_KEYLEN);
goto leave;
}
strcpy (hexkey, "key set ");
bin2hex (s, 16, hexkey+8);
/* Send the key */
{
const char *argv[4];
argv[0] = "message";
argv[1] = targetname;
argv[2] = "0";
argv[3] = NULL;
log_debug ("now running \"dmsetup message %s 0 [key set]\"\n", targetname);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, hexkey, &result, NULL);
}
wipememory (hexkey, sizeof hexkey);
if (err)
{
log_error ("error running \"dmsetup message %s 0 [key set]\": %s\n",
devname, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
xfree (result);
result = NULL;
/* Send the resume command. */
{
const char *argv[3];
argv[0] = "resume";
argv[1] = targetname;
argv[2] = NULL;
log_debug ("now running \"dmsetup resume %s\"\n", targetname);
err = gnupg_exec_tool ("/sbin/dmsetup", argv, NULL, &result, NULL);
}
if (err)
{
log_error ("error running \"dmsetup resume %s\": %s\n",
targetname, gpg_strerror (err));
goto leave;
}
if (result && *result)
log_debug ("dmsetup result: %s\n", result);
xfree (result);
result = NULL;
leave:
wipememory (hexkey, sizeof hexkey);
if (table)
{
wipememory (table, strlen (table));
xfree (table);
}
xfree (targetname_abs);
xfree (result);
return err;
}
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