source: trunk/server/source3/passdb/secrets.c

/*
   Unix SMB/CIFS implementation.
   Copyright (C) Andrew Tridgell 1992-2001
   Copyright (C) Andrew Bartlett      2002
   Copyright (C) Rafal Szczesniak     2002
   Copyright (C) Tim Potter           2001

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

/* the Samba secrets database stores any generated, private information
   such as the local SID and machine trust password */

#include "includes.h"
#include "system/filesys.h"
#include "passdb.h"
#include "../libcli/auth/libcli_auth.h"
#include "librpc/gen_ndr/ndr_secrets.h"
#include "secrets.h"
#include "dbwrap.h"
#include "../libcli/security/security.h"
#include "util_tdb.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_PASSDB

static struct db_context *db_ctx;

/**
 * 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(void *userdata, int *new_seed)
{
        *new_seed = sys_getpid();
        if (db_ctx) {
                dbwrap_trans_change_int32_atomic(db_ctx, "INFO/random_seed",
                                                 new_seed, 1);
        }
}

/* open up the secrets database */
bool secrets_init(void)
{
        char *fname = NULL;
        unsigned char dummy;

        if (db_ctx != NULL)
                return True;

        fname = talloc_asprintf(talloc_tos(), "%s/secrets.tdb",
                                lp_private_dir());
        if (fname == NULL) {
                return false;
        }

        db_ctx = db_open(NULL, fname, 0,
                         TDB_DEFAULT, O_RDWR|O_CREAT, 0600);

        if (db_ctx == NULL) {
                DEBUG(0,("Failed to open %s\n", fname));
                TALLOC_FREE(fname);
                return False;
        }

        TALLOC_FREE(fname);

        /**
         * 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, NULL);

        /* Ensure that the reseed is done now, while we are root, etc */
        generate_random_buffer(&dummy, sizeof(dummy));

        return True;
}

struct db_context *secrets_db_ctx(void)
{
        if (!secrets_init()) {
                return NULL;
        }

        return db_ctx;
}

/*
 * close secrets.tdb
 */
void secrets_shutdown(void)
{
        TALLOC_FREE(db_ctx);
}

/* 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
 */
void *secrets_fetch(const char *key, size_t *size)
{
        TDB_DATA dbuf;
        void *result;

        if (!secrets_init()) {
                return NULL;
        }

        if (db_ctx->fetch(db_ctx, talloc_tos(), string_tdb_data(key),
                          &dbuf) != 0) {
                return NULL;
        }

        result = memdup(dbuf.dptr, dbuf.dsize);
        if (result == NULL) {
                return NULL;
        }
        TALLOC_FREE(dbuf.dptr);

        if (size) {
                *size = dbuf.dsize;
        }

        return result;
}

/* store a secrets entry
 */
bool secrets_store(const char *key, const void *data, size_t size)
{
        NTSTATUS status;

        if (!secrets_init()) {
                return false;
        }

        status = dbwrap_trans_store(db_ctx, string_tdb_data(key),
                                    make_tdb_data((const uint8 *)data, size),
                                    TDB_REPLACE);
        return NT_STATUS_IS_OK(status);
}


/* delete a secets database entry
 */
bool secrets_delete(const char *key)
{
        NTSTATUS status;
        if (!secrets_init()) {
                return false;
        }

        status = dbwrap_trans_delete(db_ctx, string_tdb_data(key));

        return NT_STATUS_IS_OK(status);
}

/**
 * Form a key for fetching a trusted domain password
 *
 * @param domain trusted domain name
 *
 * @return stored password's key
 **/
static char *trustdom_keystr(const char *domain)
{
        char *keystr;

        keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
                                            SECRETS_DOMTRUST_ACCT_PASS,
                                            domain);
        SMB_ASSERT(keystr != NULL);
        return keystr;
}

/************************************************************************
 Routine to get account password to trusted domain
************************************************************************/

bool secrets_fetch_trusted_domain_password(const char *domain, char** pwd,
                                           struct dom_sid *sid, time_t *pass_last_set_time)
{
        struct TRUSTED_DOM_PASS pass;
        enum ndr_err_code ndr_err;

        /* unpacking structures */
        DATA_BLOB blob;

        /* fetching trusted domain password structure */
        if (!(blob.data = (uint8_t *)secrets_fetch(trustdom_keystr(domain),
                                                   &blob.length))) {
                DEBUG(5, ("secrets_fetch failed!\n"));
                return False;
        }

        /* unpack trusted domain password */
        ndr_err = ndr_pull_struct_blob(&blob, talloc_tos(), &pass,
                        (ndr_pull_flags_fn_t)ndr_pull_TRUSTED_DOM_PASS);

        SAFE_FREE(blob.data);

        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                return false;
        }


        /* the trust's password */
        if (pwd) {
                *pwd = SMB_STRDUP(pass.pass);
                if (!*pwd) {
                        return False;
                }
        }

        /* last change time */
        if (pass_last_set_time) *pass_last_set_time = pass.mod_time;

        /* domain sid */
        if (sid != NULL) sid_copy(sid, &pass.domain_sid);

        return True;
}

/**
 * Routine to store the password for trusted domain
 *
 * @param domain remote domain name
 * @param pwd plain text password of trust relationship
 * @param sid remote domain sid
 *
 * @return true if succeeded
 **/

bool secrets_store_trusted_domain_password(const char* domain, const char* pwd,
                                           const struct dom_sid *sid)
{
        bool ret;

        /* packing structures */
        DATA_BLOB blob;
        enum ndr_err_code ndr_err;
        struct TRUSTED_DOM_PASS pass;
        ZERO_STRUCT(pass);

        pass.uni_name = domain;
        pass.uni_name_len = strlen(domain)+1;

        /* last change time */
        pass.mod_time = time(NULL);

        /* password of the trust */
        pass.pass_len = strlen(pwd);
        pass.pass = pwd;

        /* domain sid */
        sid_copy(&pass.domain_sid, sid);

        ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &pass,
                        (ndr_push_flags_fn_t)ndr_push_TRUSTED_DOM_PASS);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                return false;
        }

        ret = secrets_store(trustdom_keystr(domain), blob.data, blob.length);

        data_blob_free(&blob);

        return ret;
}

/************************************************************************
 Routine to delete the password for trusted domain
************************************************************************/

bool trusted_domain_password_delete(const char *domain)
{
        return secrets_delete(trustdom_keystr(domain));
}

bool secrets_store_ldap_pw(const char* dn, char* pw)
{
        char *key = NULL;
        bool ret;

        if (asprintf(&key, "%s/%s", SECRETS_LDAP_BIND_PW, dn) < 0) {
                DEBUG(0, ("secrets_store_ldap_pw: asprintf failed!\n"));
                return False;
        }

        ret = secrets_store(key, pw, strlen(pw)+1);

        SAFE_FREE(key);
        return ret;
}

/*******************************************************************
 Find the ldap password.
******************************************************************/

bool fetch_ldap_pw(char **dn, char** pw)
{
        char *key = NULL;
        size_t size = 0;

        *dn = smb_xstrdup(lp_ldap_admin_dn());

        if (asprintf(&key, "%s/%s", SECRETS_LDAP_BIND_PW, *dn) < 0) {
                SAFE_FREE(*dn);
                DEBUG(0, ("fetch_ldap_pw: asprintf failed!\n"));
                return false;
        }

        *pw=(char *)secrets_fetch(key, &size);
        SAFE_FREE(key);

        if (!size) {
                /* Upgrade 2.2 style entry */
                char *p;
                char* old_style_key = SMB_STRDUP(*dn);
                char *data;
                fstring old_style_pw;

                if (!old_style_key) {
                        DEBUG(0, ("fetch_ldap_pw: strdup failed!\n"));
                        return False;
                }

                for (p=old_style_key; *p; p++)
                        if (*p == ',') *p = '/';

                data=(char *)secrets_fetch(old_style_key, &size);
                if ((data == NULL) || (size < sizeof(old_style_pw))) {
                        DEBUG(0,("fetch_ldap_pw: neither ldap secret retrieved!\n"));
                        SAFE_FREE(old_style_key);
                        SAFE_FREE(*dn);
                        SAFE_FREE(data);
                        return False;
                }

                size = MIN(size, sizeof(fstring)-1);
                strncpy(old_style_pw, data, size);
                old_style_pw[size] = 0;

                SAFE_FREE(data);

                if (!secrets_store_ldap_pw(*dn, old_style_pw)) {
                        DEBUG(0,("fetch_ldap_pw: ldap secret could not be upgraded!\n"));
                        SAFE_FREE(old_style_key);
                        SAFE_FREE(*dn);
                        return False;
                }
                if (!secrets_delete(old_style_key)) {
                        DEBUG(0,("fetch_ldap_pw: old ldap secret could not be deleted!\n"));
                }

                SAFE_FREE(old_style_key);

                *pw = smb_xstrdup(old_style_pw);
        }

        return True;
}

/**
 * Get trusted domains info from secrets.tdb.
 **/

struct list_trusted_domains_state {
        uint32 num_domains;
        struct trustdom_info **domains;
};

static int list_trusted_domain(struct db_record *rec, void *private_data)
{
        const size_t prefix_len = strlen(SECRETS_DOMTRUST_ACCT_PASS);
        struct TRUSTED_DOM_PASS pass;
        enum ndr_err_code ndr_err;
        DATA_BLOB blob;
        struct trustdom_info *dom_info;

        struct list_trusted_domains_state *state =
                (struct list_trusted_domains_state *)private_data;

        if ((rec->key.dsize < prefix_len)
            || (strncmp((char *)rec->key.dptr, SECRETS_DOMTRUST_ACCT_PASS,
                        prefix_len) != 0)) {
                return 0;
        }

        blob = data_blob_const(rec->value.dptr, rec->value.dsize);

        ndr_err = ndr_pull_struct_blob(&blob, talloc_tos(), &pass,
                        (ndr_pull_flags_fn_t)ndr_pull_TRUSTED_DOM_PASS);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                return false;
        }

        if (pass.domain_sid.num_auths != 4) {
                DEBUG(0, ("SID %s is not a domain sid, has %d "
                          "auths instead of 4\n",
                          sid_string_dbg(&pass.domain_sid),
                          pass.domain_sid.num_auths));
                return 0;
        }

        if (!(dom_info = TALLOC_P(state->domains, struct trustdom_info))) {
                DEBUG(0, ("talloc failed\n"));
                return 0;
        }

        dom_info->name = talloc_strdup(dom_info, pass.uni_name);
        if (!dom_info->name) {
                TALLOC_FREE(dom_info);
                return 0;
        }

        sid_copy(&dom_info->sid, &pass.domain_sid);

        ADD_TO_ARRAY(state->domains, struct trustdom_info *, dom_info,
                     &state->domains, &state->num_domains);

        if (state->domains == NULL) {
                state->num_domains = 0;
                return -1;
        }
        return 0;
}

NTSTATUS secrets_trusted_domains(TALLOC_CTX *mem_ctx, uint32 *num_domains,
                                 struct trustdom_info ***domains)
{
        struct list_trusted_domains_state state;

        if (!secrets_init()) {
                return NT_STATUS_ACCESS_DENIED;
        }

        state.num_domains = 0;

        /*
         * Make sure that a talloc context for the trustdom_info structs
         * exists
         */

        if (!(state.domains = TALLOC_ARRAY(
                      mem_ctx, struct trustdom_info *, 1))) {
                return NT_STATUS_NO_MEMORY;
        }

        db_ctx->traverse_read(db_ctx, list_trusted_domain, (void *)&state);

        *num_domains = state.num_domains;
        *domains = state.domains;
        return NT_STATUS_OK;
}

/*******************************************************************************
 Store a complete AFS keyfile into secrets.tdb.
*******************************************************************************/

bool secrets_store_afs_keyfile(const char *cell, const struct afs_keyfile *keyfile)
{
        fstring key;

        if ((cell == NULL) || (keyfile == NULL))
                return False;

        if (ntohl(keyfile->nkeys) > SECRETS_AFS_MAXKEYS)
                return False;

        slprintf(key, sizeof(key)-1, "%s/%s", SECRETS_AFS_KEYFILE, cell);
        return secrets_store(key, keyfile, sizeof(struct afs_keyfile));
}

/*******************************************************************************
 Fetch the current (highest) AFS key from secrets.tdb
*******************************************************************************/
bool secrets_fetch_afs_key(const char *cell, struct afs_key *result)
{
        fstring key;
        struct afs_keyfile *keyfile;
        size_t size = 0;
        uint32 i;

        slprintf(key, sizeof(key)-1, "%s/%s", SECRETS_AFS_KEYFILE, cell);

        keyfile = (struct afs_keyfile *)secrets_fetch(key, &size);

        if (keyfile == NULL)
                return False;

        if (size != sizeof(struct afs_keyfile)) {
                SAFE_FREE(keyfile);
                return False;
        }

        i = ntohl(keyfile->nkeys);

        if (i > SECRETS_AFS_MAXKEYS) {
                SAFE_FREE(keyfile);
                return False;
        }

        *result = keyfile->entry[i-1];

        result->kvno = ntohl(result->kvno);

        SAFE_FREE(keyfile);

        return True;
}

/******************************************************************************
  When kerberos is not available, choose between anonymous or
  authenticated connections.

  We need to use an authenticated connection if DCs have the
  RestrictAnonymous registry entry set > 0, or the "Additional
  restrictions for anonymous connections" set in the win2k Local
  Security Policy.

  Caller to free() result in domain, username, password
*******************************************************************************/
void secrets_fetch_ipc_userpass(char **username, char **domain, char **password)
{
        *username = (char *)secrets_fetch(SECRETS_AUTH_USER, NULL);
        *domain = (char *)secrets_fetch(SECRETS_AUTH_DOMAIN, NULL);
        *password = (char *)secrets_fetch(SECRETS_AUTH_PASSWORD, NULL);

        if (*username && **username) {

                if (!*domain || !**domain)
                        *domain = smb_xstrdup(lp_workgroup());

                if (!*password || !**password)
                        *password = smb_xstrdup("");

                DEBUG(3, ("IPC$ connections done by user %s\\%s\n",
                          *domain, *username));

        } else {
                DEBUG(3, ("IPC$ connections done anonymously\n"));
                *username = smb_xstrdup("");
                *domain = smb_xstrdup("");
                *password = smb_xstrdup("");
        }
}

bool secrets_store_generic(const char *owner, const char *key, const char *secret)
{
        char *tdbkey = NULL;
        bool ret;

        if (asprintf(&tdbkey, "SECRETS/GENERIC/%s/%s", owner, key) < 0) {
                DEBUG(0, ("asprintf failed!\n"));
                return False;
        }

        ret = secrets_store(tdbkey, secret, strlen(secret)+1);

        SAFE_FREE(tdbkey);
        return ret;
}

bool secrets_delete_generic(const char *owner, const char *key)
{
        char *tdbkey = NULL;
        bool ret;

        if (asprintf(&tdbkey, "SECRETS/GENERIC/%s/%s", owner, key) < 0) {
                DEBUG(0, ("asprintf failed!\n"));
                return False;
        }

        ret = secrets_delete(tdbkey);

        SAFE_FREE(tdbkey);
        return ret;
}

/*******************************************************************
 Find the ldap password.
******************************************************************/

char *secrets_fetch_generic(const char *owner, const char *key)
{
        char *secret = NULL;
        char *tdbkey = NULL;

        if (( ! owner) || ( ! key)) {
                DEBUG(1, ("Invalid Parameters"));
                return NULL;
        }

        if (asprintf(&tdbkey, "SECRETS/GENERIC/%s/%s", owner, key) < 0) {
                DEBUG(0, ("Out of memory!\n"));
                return NULL;
        }

        secret = (char *)secrets_fetch(tdbkey, NULL);
        SAFE_FREE(tdbkey);

        return secret;
}