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/*
Unix SMB/CIFS implementation.
Copyright (C) Andrew Tridgell 1992-2001
Copyright (C) Andrew Bartlett 2002
Copyright (C) Rafal Szczesniak 2002
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* the Samba secrets database stores any generated, private information
such as the local SID and machine trust password */
#include "includes.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_PASSDB
static struct tdb_wrap *tdb;
/**
* Use a TDB to store an incrementing random seed.
*
* Initialised to the current pid, the very first time Samba starts,
* and incremented by one each time it is needed.
*
* @note Not called by systems with a working /dev/urandom.
*/
static void get_rand_seed(int *new_seed)
{
*new_seed = getpid();
if (tdb) {
tdb_change_int32_atomic(tdb->tdb, "INFO/random_seed", new_seed, 1);
}
}
/* close the secrets database */
void secrets_shutdown(void)
{
talloc_free(tdb);
}
/* open up the secrets database */
BOOL secrets_init(void)
{
pstring fname;
char dummy;
if (tdb)
return True;
pstrcpy(fname, lp_private_dir());
pstrcat(fname,"/secrets.tdb");
tdb = tdb_wrap_open(NULL, fname, 0, TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
if (!tdb) {
DEBUG(0,("Failed to open %s\n", fname));
return False;
}
/**
* Set a reseed function for the crypto random generator
*
* This avoids a problem where systems without /dev/urandom
* could send the same challenge to multiple clients
*/
set_rand_reseed_callback(get_rand_seed);
/* Ensure that the reseed is done now, while we are root, etc */
generate_random_buffer(&dummy, sizeof(dummy));
return True;
}
/* read a entry from the secrets database - the caller must free the result
if size is non-null then the size of the entry is put in there
*/
static void *secrets_fetch(const char *key, size_t *size)
{
TDB_DATA kbuf, dbuf;
secrets_init();
if (!tdb)
return NULL;
kbuf.dptr = strdup(key);
kbuf.dsize = strlen(key);
dbuf = tdb_fetch(tdb->tdb, kbuf);
if (size)
*size = dbuf.dsize;
free(kbuf.dptr);
return dbuf.dptr;
}
/************************************************************************
Routine to fetch the plaintext machine account password for a realm
the password is assumed to be a null terminated ascii string
************************************************************************/
char *secrets_fetch_machine_password(const char *domain)
{
char *key;
char *ret;
asprintf(&key, "%s/%s", SECRETS_MACHINE_PASSWORD, domain);
strupper(key);
ret = (char *)secrets_fetch(key, NULL);
free(key);
return ret;
}
/*******************************************************************************
Lock the secrets tdb based on a string - this is used as a primitive form of mutex
between smbd instances.
*******************************************************************************/
BOOL secrets_named_mutex(const char *name, uint_t timeout, size_t *p_ref_count)
{
size_t ref_count = *p_ref_count;
int ret = 0;
if (ref_count == 0) {
ret = tdb_lock_bystring(tdb->tdb, name, timeout);
if (ret == 0)
DEBUG(10,("secrets_named_mutex: got mutex for %s\n", name ));
}
if (ret == 0) {
*p_ref_count = ++ref_count;
DEBUG(10,("secrets_named_mutex: ref_count for mutex %s = %u\n", name, (uint_t)ref_count ));
}
return (ret == 0);
}
/*******************************************************************************
Unlock a named mutex.
*******************************************************************************/
void secrets_named_mutex_release(const char *name, size_t *p_ref_count)
{
size_t ref_count = *p_ref_count;
SMB_ASSERT(ref_count != 0);
if (ref_count == 1) {
tdb_unlock_bystring(tdb->tdb, name);
DEBUG(10,("secrets_named_mutex: released mutex for %s\n", name ));
}
*p_ref_count = --ref_count;
DEBUG(10,("secrets_named_mutex_release: ref_count for mutex %s = %u\n", name, (uint_t)ref_count ));
}
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