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/* mount.c - Mount a crypto container
* Copyright (C) 2009 Free Software Foundation, Inc.
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include <assert.h>
#include "g13.h"
#include "i18n.h"
#include "mount.h"
#include "keyblob.h"
#include "backend.h"
#include "g13tuple.h"
#include "mountinfo.h"
#include "runner.h"
#include "host2net.h"
#include "server.h" /*(g13_keyblob_decrypt)*/
#include "../common/sysutils.h"
/* Mount the container with name FILENAME at MOUNTPOINT. */
gpg_error_t
g13_mount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
{
gpg_error_t err;
dotlock_t lock;
int needs_syshelp;
void *enckeyblob = NULL;
size_t enckeybloblen;
void *keyblob = NULL;
size_t keybloblen;
tupledesc_t tuples = NULL;
size_t n;
const unsigned char *value;
int conttype;
unsigned int rid;
char *mountpoint_buffer = NULL;
/* A quick check to see whether the container exists. */
if (access (filename, R_OK))
return gpg_error_from_syserror ();
/* Decide whether we need to use the g13-syshelp because we can't
use lock files for them. This is most likely the case for device
files; thus we test for this. FIXME: The correct solution would
be to call g13-syshelp to match the file against the g13tab. */
needs_syshelp = !strncmp (filename, "/dev/", 5);
if (!mountpoint)
{
mountpoint_buffer = xtrystrdup ("/tmp/g13-XXXXXX");
if (!mountpoint_buffer)
return gpg_error_from_syserror ();
if (!gnupg_mkdtemp (mountpoint_buffer))
{
err = gpg_error_from_syserror ();
log_error (_("can't create directory '%s': %s\n"),
"/tmp/g13-XXXXXX", gpg_strerror (err));
xfree (mountpoint_buffer);
return err;
}
mountpoint = mountpoint_buffer;
}
err = 0;
if (needs_syshelp)
lock = NULL;
else
{
/* Try to take a lock. */
lock = dotlock_create (filename, 0);
if (!lock)
{
xfree (mountpoint_buffer);
return gpg_error_from_syserror ();
}
if (dotlock_take (lock, 0))
{
err = gpg_error_from_syserror ();
goto leave;
}
}
/* Check again that the file exists. */
{
struct stat sb;
if (stat (filename, &sb))
{
err = gpg_error_from_syserror ();
goto leave;
}
}
/* Read the encrypted keyblob. */
/* Fixme: Should we move this to syshelp for dm-crypt or do we
assume that the encrypted device is world readable? */
err = g13_keyblob_read (filename, &enckeyblob, &enckeybloblen);
if (err)
goto leave;
/* Decrypt that keyblob and store it in a tuple descriptor. */
err = g13_keyblob_decrypt (ctrl, enckeyblob, enckeybloblen,
&keyblob, &keybloblen);
if (err)
goto leave;
xfree (enckeyblob);
enckeyblob = NULL;
err = create_tupledesc (&tuples, keyblob, keybloblen);
if (!err)
keyblob = NULL;
else
{
if (gpg_err_code (err) == GPG_ERR_NOT_SUPPORTED)
log_error ("unknown keyblob version\n");
goto leave;
}
if (opt.verbose)
dump_tupledesc (tuples);
value = find_tuple (tuples, KEYBLOB_TAG_CONTTYPE, &n);
if (!value || n != 2)
conttype = 0;
else
conttype = (value[0] << 8 | value[1]);
if (!be_is_supported_conttype (conttype))
{
log_error ("content type %d is not supported\n", conttype);
err = gpg_error (GPG_ERR_NOT_SUPPORTED);
goto leave;
}
err = be_mount_container (ctrl, conttype, filename, mountpoint, tuples, &rid);
if (err)
;
else if (conttype == CONTTYPE_DM_CRYPT)
g13_request_shutdown ();
else
{
/* Unless this is a DM-CRYPT mount we put it into our mounttable
so that we can manage the mounts ourselves. For dm-crypt we
do not keep a process to monitor he mounts (for now). */
err = mountinfo_add_mount (filename, mountpoint, conttype, rid,
!!mountpoint_buffer);
/* Fixme: What shall we do if this fails? Add a provisional
mountinfo entry first and remove it on error? */
if (!err)
{
char *tmp = percent_plus_escape (mountpoint);
if (!tmp)
err = gpg_error_from_syserror ();
else
{
g13_status (ctrl, STATUS_MOUNTPOINT, tmp, NULL);
xfree (tmp);
}
}
}
leave:
destroy_tupledesc (tuples);
xfree (keyblob);
xfree (enckeyblob);
dotlock_destroy (lock);
xfree (mountpoint_buffer);
return err;
}
/* Unmount the container with name FILENAME or the one mounted at
MOUNTPOINT. If both are given the FILENAME takes precedence. */
gpg_error_t
g13_umount_container (ctrl_t ctrl, const char *filename, const char *mountpoint)
{
gpg_error_t err;
unsigned int rid;
runner_t runner;
(void)ctrl;
if (!filename && !mountpoint)
return gpg_error (GPG_ERR_ENOENT);
err = mountinfo_find_mount (filename, mountpoint, &rid);
if (err)
return err;
runner = runner_find_by_rid (rid);
if (!runner)
{
log_error ("runner %u not found\n", rid);
return gpg_error (GPG_ERR_NOT_FOUND);
}
runner_cancel (runner);
runner_release (runner);
return 0;
}
|
