s3:rpc_server: Handle an np_read_send with len==0 correctly

[samba.git] / source3 / auth / check_samsec.c

/*
   Unix SMB/CIFS implementation.
   Password and authentication handling
   Copyright (C) Andrew Tridgell              1992-2000
   Copyright (C) Luke Kenneth Casson Leighton 1996-2000
   Copyright (C) Andrew Bartlett              2001-2003
   Copyright (C) Gerald Carter                2003

   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/>.
*/

#include "includes.h"
#include "auth.h"
#include "../libcli/auth/libcli_auth.h"
#include "passdb.h"
#include "lib/util/memcache.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_AUTH

/****************************************************************************
 Do a specific test for an smb password being correct, given a smb_password and
 the lanman and NT responses.
****************************************************************************/

static NTSTATUS sam_password_ok(TALLOC_CTX *mem_ctx,
                                const char *username,
                                uint32_t acct_ctrl,
                                const DATA_BLOB *challenge,
                                const uint8_t *lm_pw,
                                const uint8_t *nt_pw,
                                const struct auth_usersupplied_info *user_info,
                                DATA_BLOB *user_sess_key,
                                DATA_BLOB *lm_sess_key)
{
        NTSTATUS status;
        struct samr_Password _lm_hash, _nt_hash;
        struct samr_Password *lm_hash = NULL;
        struct samr_Password *nt_hash = NULL;

        *user_sess_key = data_blob_null;
        *lm_sess_key = data_blob_null;

        if (acct_ctrl & ACB_PWNOTREQ) {
                if (lp_null_passwords()) {
                        DEBUG(3,("Account for user '%s' has no password and null passwords are allowed.\n", username));
                        return NT_STATUS_OK;
                } else {
                        DEBUG(3,("Account for user '%s' has no password and null passwords are NOT allowed.\n", username));
                        return NT_STATUS_LOGON_FAILURE;
                }
        }

        if (lm_pw) {
                memcpy(_lm_hash.hash, lm_pw, sizeof(_lm_hash.hash));
                lm_hash = &_lm_hash;
        }
        if (nt_pw) {
                memcpy(_nt_hash.hash, nt_pw, sizeof(_nt_hash.hash));
                nt_hash = &_nt_hash;
        }
        switch (user_info->password_state) {
        case AUTH_PASSWORD_HASH:
                status = hash_password_check(mem_ctx, lp_lanman_auth(),
                                             lp_ntlm_auth(),
                                             user_info->password.hash.lanman,
                                             user_info->password.hash.nt,
                                             username,
                                             lm_hash,
                                             nt_hash);
                if (NT_STATUS_IS_OK(status)) {
                        if (nt_pw) {
                                *user_sess_key = data_blob_talloc(mem_ctx, NULL, 16);
                                if (!user_sess_key->data) {
                                        status = NT_STATUS_NO_MEMORY;
                                        goto done;
                                }
                                SMBsesskeygen_ntv1(nt_pw, user_sess_key->data);
                        }
                }
                break;

        /* Eventually we should test plaintext passwords in their own
         * function, not assuming the caller has done a
         * mapping */
        case AUTH_PASSWORD_PLAIN:
        case AUTH_PASSWORD_RESPONSE:
                status = ntlm_password_check(mem_ctx, lp_lanman_auth(),
                                           lp_ntlm_auth(),
                                           user_info->logon_parameters,
                                           challenge,
                                           &user_info->password.response.lanman, &user_info->password.response.nt,
                                           username,
                                           user_info->client.account_name,
                                           user_info->client.domain_name,
                                           lm_hash,
                                           nt_hash,
                                           user_sess_key, lm_sess_key);
                break;
        default:
                DEBUG(0,("user_info constructed for user '%s' was invalid - password_state=%u invalid.\n", username, user_info->password_state));
                status = NT_STATUS_INTERNAL_ERROR;
        }
done:
        ZERO_STRUCTP(lm_hash);
        ZERO_STRUCTP(nt_hash);
        return status;
}

/****************************************************************************
 Check if a user is allowed to logon at this time. Note this is the
 servers local time, as logon hours are just specified as a weekly
 bitmask.
****************************************************************************/

static bool logon_hours_ok(struct samu *sampass)
{
        /* In logon hours first bit is Sunday from 12AM to 1AM */
        const uint8_t *hours;
        struct tm *utctime;
        time_t lasttime;
        const char *asct;
        uint8_t bitmask, bitpos;

        hours = pdb_get_hours(sampass);
        if (!hours) {
                DEBUG(5,("logon_hours_ok: No hours restrictions for user %s\n",pdb_get_username(sampass)));
                return True;
        }

        lasttime = time(NULL);
        utctime = gmtime(&lasttime);
        if (!utctime) {
                DEBUG(1, ("logon_hours_ok: failed to get gmtime. Failing logon for user %s\n",
                        pdb_get_username(sampass) ));
                return False;
        }

        /* find the corresponding byte and bit */
        bitpos = (utctime->tm_wday * 24 + utctime->tm_hour) % 168;
        bitmask = 1 << (bitpos % 8);

        if (! (hours[bitpos/8] & bitmask)) {
                struct tm *t = localtime(&lasttime);
                if (!t) {
                        asct = "INVALID TIME";
                } else {
                        asct = asctime(t);
                        if (!asct) {
                                asct = "INVALID TIME";
                        }
                }

                DEBUG(1, ("logon_hours_ok: Account for user %s not allowed to "
                          "logon at this time (%s).\n",
                          pdb_get_username(sampass), asct ));
                return False;
        }

        asct = asctime(utctime);
        DEBUG(5,("logon_hours_ok: user %s allowed to logon at this time (%s)\n",
                pdb_get_username(sampass), asct ? asct : "UNKNOWN TIME" ));

        return True;
}

/****************************************************************************
 Do a specific test for a struct samu being valid for this connection
 (ie not disabled, expired and the like).
****************************************************************************/

static NTSTATUS sam_account_ok(TALLOC_CTX *mem_ctx,
                               struct samu *sampass,
                               const struct auth_usersupplied_info *user_info)
{
        uint32_t acct_ctrl = pdb_get_acct_ctrl(sampass);
        char *workstation_list;
        time_t kickoff_time;

        DEBUG(4,("sam_account_ok: Checking SMB password for user %s\n",pdb_get_username(sampass)));

        /* Quit if the account was disabled. */
        if (acct_ctrl & ACB_DISABLED) {
                DEBUG(1,("sam_account_ok: Account for user '%s' was disabled.\n", pdb_get_username(sampass)));
                return NT_STATUS_ACCOUNT_DISABLED;
        }

        /* Quit if the account was locked out. */
        if (acct_ctrl & ACB_AUTOLOCK) {
                DEBUG(1,("sam_account_ok: Account for user %s was locked out.\n", pdb_get_username(sampass)));
                return NT_STATUS_ACCOUNT_LOCKED_OUT;
        }

        /* Quit if the account is not allowed to logon at this time. */
        if (! logon_hours_ok(sampass)) {
                return NT_STATUS_INVALID_LOGON_HOURS;
        }

        /* Test account expire time */

        kickoff_time = pdb_get_kickoff_time(sampass);
        if (kickoff_time != 0 && time(NULL) > kickoff_time) {
                DEBUG(1,("sam_account_ok: Account for user '%s' has expired.\n", pdb_get_username(sampass)));
                DEBUG(3,("sam_account_ok: Account expired at '%ld' unix time.\n", (long)kickoff_time));
                return NT_STATUS_ACCOUNT_EXPIRED;
        }

        if (!(pdb_get_acct_ctrl(sampass) & ACB_PWNOEXP) && !(pdb_get_acct_ctrl(sampass) & ACB_PWNOTREQ)) {
                time_t must_change_time = pdb_get_pass_must_change_time(sampass);
                time_t last_set_time = pdb_get_pass_last_set_time(sampass);

                /* check for immediate expiry "must change at next logon"
                 * for a user account. */
                if (((acct_ctrl & (ACB_WSTRUST|ACB_SVRTRUST)) == 0) && (last_set_time == 0)) {
                        DEBUG(1,("sam_account_ok: Account for user '%s' password must change!\n", pdb_get_username(sampass)));
                        return NT_STATUS_PASSWORD_MUST_CHANGE;
                }

                /* check for expired password */
                if (must_change_time < time(NULL) && must_change_time != 0) {
                        DEBUG(1,("sam_account_ok: Account for user '%s' password expired!\n", pdb_get_username(sampass)));
                        DEBUG(1,("sam_account_ok: Password expired at '%s' (%ld) unix time.\n", http_timestring(talloc_tos(), must_change_time), (long)must_change_time));
                        return NT_STATUS_PASSWORD_EXPIRED;
                }
        }

        /* Test workstation. Workstation list is comma separated. */

        workstation_list = talloc_strdup(mem_ctx, pdb_get_workstations(sampass));
        if (!workstation_list)
                return NT_STATUS_NO_MEMORY;

        if (*workstation_list) {
                bool invalid_ws = True;
                char *tok = NULL;
                const char *s = workstation_list;
                char *machine_name = talloc_asprintf(mem_ctx, "%s$", user_info->workstation_name);

                if (machine_name == NULL)
                        return NT_STATUS_NO_MEMORY;

                while (next_token_talloc(mem_ctx, &s, &tok, ",")) {
                        DEBUG(10,("sam_account_ok: checking for workstation match %s and %s\n",
                                  tok, user_info->workstation_name));
                        if(strequal(tok, user_info->workstation_name)) {
                                invalid_ws = False;
                                break;
                        }
                        if (tok[0] == '+') {
                                DEBUG(10,("sam_account_ok: checking for workstation %s in group: %s\n",
                                        machine_name, tok + 1));
                                if (user_in_group(machine_name, tok + 1)) {
                                        invalid_ws = False;
                                        break;
                                }
                        }
                        TALLOC_FREE(tok);
                }
                TALLOC_FREE(tok);
                TALLOC_FREE(machine_name);

                if (invalid_ws)
                        return NT_STATUS_INVALID_WORKSTATION;
        }

        if (acct_ctrl & ACB_DOMTRUST) {
                DEBUG(2,("sam_account_ok: Domain trust account %s denied by server\n", pdb_get_username(sampass)));
                return NT_STATUS_NOLOGON_INTERDOMAIN_TRUST_ACCOUNT;
        }

        if (acct_ctrl & ACB_SVRTRUST) {
                if (!(user_info->logon_parameters & MSV1_0_ALLOW_SERVER_TRUST_ACCOUNT)) {
                        DEBUG(2,("sam_account_ok: Server trust account %s denied by server\n", pdb_get_username(sampass)));
                        return NT_STATUS_NOLOGON_SERVER_TRUST_ACCOUNT;
                }
        }

        if (acct_ctrl & ACB_WSTRUST) {
                if (!(user_info->logon_parameters & MSV1_0_ALLOW_WORKSTATION_TRUST_ACCOUNT)) {
                        DEBUG(2,("sam_account_ok: Wksta trust account %s denied by server\n", pdb_get_username(sampass)));
                        return NT_STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT;
                }
        }
        return NT_STATUS_OK;
}

/**
 * Check whether the given password is one of the last two
 * password history entries. If so, the bad pwcount should
 * not be incremented even though the actual password check
 * failed.
 */
static bool need_to_increment_bad_pw_count(
        const DATA_BLOB *challenge,
        struct samu* sampass,
        const struct auth_usersupplied_info *user_info)
{
        uint8_t i;
        const uint8_t *pwhistory;
        uint32_t pwhistory_len;
        uint32_t policy_pwhistory_len;
        uint32_t acct_ctrl;
        const char *username;
        TALLOC_CTX *mem_ctx = talloc_stackframe();
        bool result = true;

        pdb_get_account_policy(PDB_POLICY_PASSWORD_HISTORY,
                               &policy_pwhistory_len);
        if (policy_pwhistory_len == 0) {
                goto done;
        }

        pwhistory = pdb_get_pw_history(sampass, &pwhistory_len);
        if (!pwhistory || pwhistory_len == 0) {
                goto done;
        }

        acct_ctrl = pdb_get_acct_ctrl(sampass);
        username = pdb_get_username(sampass);

        for (i=1; i < MIN(MIN(3, policy_pwhistory_len), pwhistory_len); i++) {
                const uint8_t *salt;
                const uint8_t *nt_pw;
                NTSTATUS status;
                DATA_BLOB user_sess_key = data_blob_null;
                DATA_BLOB lm_sess_key = data_blob_null;

                salt = &pwhistory[i*PW_HISTORY_ENTRY_LEN];
                nt_pw = salt + PW_HISTORY_SALT_LEN;

                if (all_zero(nt_pw, NT_HASH_LEN)) {
                        /* skip zero password hash */
                        continue;
                }

                if (!all_zero(salt, PW_HISTORY_SALT_LEN)) {
                        /* skip nonzero salt (old format entry) */
                        continue;
                }

                status = sam_password_ok(mem_ctx,
                                         username, acct_ctrl,
                                         challenge,
                                         NULL, nt_pw,
                                         user_info, &user_sess_key, &lm_sess_key);
                if (NT_STATUS_IS_OK(status)) {
                        result = false;
                        break;
                }
        }

done:
        TALLOC_FREE(mem_ctx);
        return result;
}

/****************************************************************************
check if a username/password is OK assuming the password is a 24 byte
SMB hash supplied in the user_info structure
return an NT_STATUS constant.
****************************************************************************/

NTSTATUS check_sam_security(const DATA_BLOB *challenge,
                            TALLOC_CTX *mem_ctx,
                            const struct auth_usersupplied_info *user_info,
                            struct auth_serversupplied_info **server_info)
{
        struct samu *sampass=NULL;
        bool ret;
        NTSTATUS nt_status;
        NTSTATUS update_login_attempts_status;
        DATA_BLOB user_sess_key = data_blob_null;
        DATA_BLOB lm_sess_key = data_blob_null;
        bool updated_badpw = False;
        const char *username;
        const uint8_t *nt_pw;
        const uint8_t *lm_pw;
        uint32_t acct_ctrl;
        char *mutex_name_by_user = NULL;
        struct named_mutex *mtx = NULL;

        /* the returned struct gets kept on the server_info, by means
           of a steal further down */

        sampass = samu_new(mem_ctx);
        if (sampass == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        /* get the account information */

        become_root();
        ret = pdb_getsampwnam(sampass, user_info->mapped.account_name);
        unbecome_root();

        if (!ret) {
                DEBUG(3,("check_sam_security: Couldn't find user '%s' in "
                         "passdb.\n", user_info->mapped.account_name));
                TALLOC_FREE(sampass);
                return NT_STATUS_NO_SUCH_USER;
        }

        acct_ctrl = pdb_get_acct_ctrl(sampass);
        username = pdb_get_username(sampass);
        nt_pw = pdb_get_nt_passwd(sampass);
        lm_pw = pdb_get_lanman_passwd(sampass);

        /* Quit if the account was locked out. */
        if (acct_ctrl & ACB_AUTOLOCK) {
                DEBUG(3,("check_sam_security: Account for user %s was locked out.\n", username));
                TALLOC_FREE(sampass);
                return NT_STATUS_ACCOUNT_LOCKED_OUT;
        }

        nt_status = sam_password_ok(mem_ctx,
                                    username, acct_ctrl,
                                    challenge, lm_pw, nt_pw,
                                    user_info, &user_sess_key, &lm_sess_key);

        /*
         * We must re-load the sam account information under a mutex
         * lock to ensure we don't miss any concurrent account lockout
         * changes.
         */

        /* Clear out old sampass info. */
        TALLOC_FREE(sampass);
        acct_ctrl = 0;
        username = NULL;
        nt_pw = NULL;
        lm_pw = NULL;

        sampass = samu_new(mem_ctx);
        if (sampass == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        mutex_name_by_user = talloc_asprintf(mem_ctx,
                                             "check_sam_security_mutex_%s",
                                             user_info->mapped.account_name);
        if (mutex_name_by_user == NULL) {
                nt_status = NT_STATUS_NO_MEMORY;
                goto done;
        }

        /* Grab the named mutex under root with 30 second timeout. */
        become_root();
        mtx = grab_named_mutex(mem_ctx, mutex_name_by_user, 30);
        if (mtx != NULL) {
                /* Re-load the account information if we got the mutex. */
                ret = pdb_getsampwnam(sampass, user_info->mapped.account_name);
        }
        unbecome_root();

        /* Everything from here on until mtx is freed is done under the mutex.*/

        if (mtx == NULL) {
                DBG_ERR("Acquisition of mutex %s failed "
                        "for user %s\n",
                        mutex_name_by_user,
                        user_info->mapped.account_name);
                nt_status = NT_STATUS_INTERNAL_ERROR;
                goto done;
        }

        if (!ret) {
                /*
                 * Re-load of account failed. This could only happen if the
                 * user was deleted in the meantime.
                 */
                DBG_NOTICE("reload of user '%s' in passdb failed.\n",
                           user_info->mapped.account_name);
                nt_status = NT_STATUS_NO_SUCH_USER;
                goto done;
        }

        /* Re-load the account control info. */
        acct_ctrl = pdb_get_acct_ctrl(sampass);
        username = pdb_get_username(sampass);

        /*
         * Check if the account is now locked out - now under the mutex.
         * This can happen if the server is under
         * a password guess attack and the ACB_AUTOLOCK is set by
         * another process.
         */
        if (acct_ctrl & ACB_AUTOLOCK) {
                DBG_NOTICE("Account for user %s was locked out.\n", username);
                nt_status = NT_STATUS_ACCOUNT_LOCKED_OUT;
                goto done;
        }

        /* Notify passdb backend of login success/failure. If not
           NT_STATUS_OK the backend doesn't like the login */

        update_login_attempts_status = pdb_update_login_attempts(sampass, NT_STATUS_IS_OK(nt_status));

        if (!NT_STATUS_IS_OK(nt_status)) {
                bool increment_bad_pw_count = false;

                if (NT_STATUS_EQUAL(nt_status,NT_STATUS_WRONG_PASSWORD) &&
                    (acct_ctrl & ACB_NORMAL) &&
                    NT_STATUS_IS_OK(update_login_attempts_status))
                {
                        increment_bad_pw_count =
                                need_to_increment_bad_pw_count(
                                        challenge, sampass, user_info);
                }

                if (increment_bad_pw_count) {
                        pdb_increment_bad_password_count(sampass);
                        updated_badpw = True;
                } else {
                        pdb_update_bad_password_count(sampass,
                                                      &updated_badpw);
                }
                if (updated_badpw){
                        NTSTATUS status;

                        become_root();
                        status = pdb_update_sam_account(sampass);
                        unbecome_root();

                        if (!NT_STATUS_IS_OK(status)) {
                                DEBUG(1, ("Failed to modify entry: %s\n",
                                          nt_errstr(status)));
                        }
                }
                goto done;
        }

        /*
         * We must only reset the bad password count if the login was
         * successful, including checking account policies
         */
        nt_status = sam_account_ok(mem_ctx, sampass, user_info);
        if (!NT_STATUS_IS_OK(nt_status)) {
                goto done;
        }

        if ((acct_ctrl & ACB_NORMAL) &&
            (pdb_get_bad_password_count(sampass) > 0)){
                NTSTATUS status;

                pdb_set_bad_password_count(sampass, 0, PDB_CHANGED);
                pdb_set_bad_password_time(sampass, 0, PDB_CHANGED);

                become_root();
                status = pdb_update_sam_account(sampass);
                unbecome_root();

                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(1, ("Failed to modify entry: %s\n",
                                  nt_errstr(status)));
                }
        }

        become_root();
        nt_status = make_server_info_sam(mem_ctx, sampass, server_info);
        unbecome_root();

        if (!NT_STATUS_IS_OK(nt_status)) {
                DEBUG(0,("check_sam_security: make_server_info_sam() failed with '%s'\n", nt_errstr(nt_status)));
                goto done;
        }

        (*server_info)->info3->base.user_flags |= NETLOGON_NTLMV2_ENABLED;

        (*server_info)->session_key =
                data_blob_talloc(*server_info, user_sess_key.data,
                                 user_sess_key.length);
        data_blob_free(&user_sess_key);

        (*server_info)->lm_session_key =
                data_blob_talloc(*server_info, lm_sess_key.data,
                                 lm_sess_key.length);
        data_blob_free(&lm_sess_key);

        (*server_info)->nss_token |= user_info->was_mapped;

done:
        /*
         * Always flush the getpwsid cache or this will grow indefinitely for
         * each NTLM auththentication.
         */
        memcache_flush(NULL, PDB_GETPWSID_CACHE);
        TALLOC_FREE(sampass);
        data_blob_free(&user_sess_key);
        data_blob_free(&lm_sess_key);
        TALLOC_FREE(mutex_name_by_user);
        TALLOC_FREE(mtx);
        return nt_status;
}

/* This helper function for winbindd returns a very similar value to
 * what a NETLOGON call would give, without the indirection */
NTSTATUS check_sam_security_info3(const DATA_BLOB *challenge,
                                  TALLOC_CTX *mem_ctx,
                                  const struct auth_usersupplied_info *user_info,
                                  struct netr_SamInfo3 **pinfo3)
{
        struct auth_serversupplied_info *server_info = NULL;
        struct netr_SamInfo3 *info3;
        NTSTATUS status;
        TALLOC_CTX *frame = talloc_stackframe();

        status = check_sam_security(challenge, talloc_tos(), user_info,
                                    &server_info);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(10, ("check_sam_security failed: %s\n",
                           nt_errstr(status)));
                goto done;
        }

        info3 = talloc_zero(mem_ctx, struct netr_SamInfo3);
        if (info3 == NULL) {
                status = NT_STATUS_NO_MEMORY;
                goto done;
        }

        status = serverinfo_to_SamInfo3(server_info, info3);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(10, ("serverinfo_to_SamInfo3 failed: %s\n",
                           nt_errstr(status)));
                goto done;
        }
        *pinfo3 = info3;
        status =  NT_STATUS_OK;
done:
        TALLOC_FREE(frame);
        return status;
}