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/**
* Copyright (C) 2009 International Business Machines
* Author(s): Tyler Hicks <tyhicks@linux.vnet.ibm.com>
*
* This program 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 2 of the
* License, or (at your option) any later version.
*
* 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 <errno.h>
#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "ecryptfs.h"
static void usage()
{
fprintf(stderr, "\teCryptfs umount helper\n\tusage: "
"umount [ecryptfs mount point]\n"
);
exit(-EINVAL);
}
/**
* Parses a string of mount options, searching for an option name, and returns
* a pointer to the option value. For example, if name was "ecryptfs_sig=",
* it would set value to a string containing the sig, up to the first
* comma or NULL character in the mount options. Name must end with an = sign.
* value must be freed by the caller.
*/
static int get_mount_opt_value(char *mnt_opts, char *name, char **value)
{
char *name_start, *val_start, *val_stop;
size_t name_len, val_len;
int rc = 0;
name_len = strlen(name);
if (name[name_len - 1] != '=') {
rc = EINVAL;
goto out;
}
name_start = strstr(mnt_opts, name);
if (!name_start) {
rc = EINVAL;
goto out;
}
val_start = name_start + name_len;
val_stop = strstr(val_start, ",");
if (!val_stop)
val_stop = mnt_opts + strlen(mnt_opts);
val_len = val_stop - val_start;
*value = malloc(val_len + 1);
if (!(*value)) {
rc = ENOMEM;
goto out;
}
memcpy(*value, val_start, val_len);
(*value)[val_len] = '\0';
out:
return rc;
}
static int unlink_keys_from_keyring(const char *mnt_point)
{
struct mntent *mntent;
FILE *file;
char *fekek_sig = NULL, *fnek_sig = NULL;
int fekek_fail = 0, fnek_fail = 0;
int rc;
file = setmntent("/etc/mtab", "r");
if (!file) {
rc = EINVAL;
goto out;
}
while ((mntent = getmntent(file))) {
if (strcmp("ecryptfs", mntent->mnt_type))
continue;
if (strcmp(mnt_point, mntent->mnt_dir))
continue;
break;
}
if (!mntent) {
rc = EINVAL;
goto end_out;
}
if (!hasmntopt(mntent, "ecryptfs_unlink_sigs")) {
rc = 0;
goto end_out;
}
rc = get_mount_opt_value(mntent->mnt_opts, "ecryptfs_sig=", &fekek_sig);
if (!rc) {
fekek_fail = ecryptfs_remove_auth_tok_from_keyring(fekek_sig);
if (fekek_fail == ENOKEY)
fekek_fail = 0;
if (fekek_fail)
fprintf(stderr, "Failed to remove fekek with sig [%s] "
"from keyring: %s\n", fekek_sig,
strerror(fekek_fail));
} else {
fekek_fail = rc;
}
if (!get_mount_opt_value(mntent->mnt_opts,
"ecryptfs_fnek_sig=", &fnek_sig)
&& strcmp(fekek_sig, fnek_sig)) {
fnek_fail = ecryptfs_remove_auth_tok_from_keyring(fnek_sig);
if (fnek_fail == ENOKEY)
fnek_fail = 0;
if (fnek_fail) {
fprintf(stderr, "Failed to remove fnek with sig [%s] "
"from keyring: %s\n", fnek_sig,
strerror(fnek_fail));
}
}
free(fekek_sig);
free(fnek_sig);
end_out:
endmntent(file);
out:
return (fekek_fail ? fekek_fail : (fnek_fail ? fnek_fail : rc));
}
static int construct_umount_args(int argc, char **argv, char ***new_argv)
{
int new_argc = argc + 1;
int i, rc;
*new_argv = malloc(sizeof(char *) * (new_argc + 1));
if (!*new_argv) {
rc = errno;
goto out;
}
(*new_argv)[0] = "umount";
(*new_argv)[1] = "-i";
for (i = 2; i < new_argc; i++)
(*new_argv)[i] = argv[i - 1];
(*new_argv)[i] = NULL;
rc = 0;
out:
return rc;
}
#define UMOUNT_PATH "/bin/umount"
int main(int argc, char **argv)
{
char **new_argv;
int rc;
if (argc<2)
usage();
if (unlink_keys_from_keyring(argv[1]))
fprintf(stderr, "Could not unlink the key(s) from your keying. "
"Please use `keyctl unlink` if you wish to remove the "
"key(s). Proceeding with umount.\n");
rc = construct_umount_args(argc, argv, &new_argv);
if (rc) {
fprintf(stderr, "Failed to construct umount arguments: %s\n",
strerror(rc));
goto out;
}
rc = execv(UMOUNT_PATH, new_argv);
if (rc < 0) {
rc = errno;
fprintf(stderr, "Failed to execute %s: %m\n", UMOUNT_PATH);
goto free_out;
}
rc = 0;
free_out:
free(new_argv);
out:
return rc;
}
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