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"

#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(),
					     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) {
					return NT_STATUS_NO_MEMORY;
				}
				SMBsesskeygen_ntv1(nt_pw, user_sess_key->data);
			}
		}
		return status;

	/* 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:
		return 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);
	default:
		DEBUG(0,("user_info constructed for user '%s' was invalid - password_state=%u invalid.\n", username, user_info->password_state));
		return NT_STATUS_INTERNAL_ERROR;
	}
}

/****************************************************************************
 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 *hours;
	struct tm *utctime;
	time_t lasttime;
	const char *asct;
	uint8 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	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 thought 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++) {
		static const uint8_t zero16[SALTED_MD5_HASH_LEN];
		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 (memcmp(zero16, nt_pw, NT_HASH_LEN) == 0) {
			/* skip zero password hash */
			continue;
		}

		if (memcmp(zero16, salt, PW_HISTORY_SALT_LEN) != 0) {
			/* 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;

	/* 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 == False) {
		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;
	}

	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 (pdb_get_acct_ctrl(sampass) & 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, pdb_get_acct_ctrl(sampass),
				    challenge, lm_pw, nt_pw,
				    user_info, &user_sess_key, &lm_sess_key);

	/* 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) &&
		    pdb_get_acct_ctrl(sampass) & 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;
	}

	if ((pdb_get_acct_ctrl(sampass) & ACB_NORMAL) &&
	    (pdb_get_bad_password_count(sampass) > 0)){
		pdb_set_bad_password_count(sampass, 0, PDB_CHANGED);
		pdb_set_bad_password_time(sampass, 0, PDB_CHANGED);
		updated_badpw = True;
	}

	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)));
		}
	}

	nt_status = sam_account_ok(mem_ctx, sampass, user_info);

	if (!NT_STATUS_IS_OK(nt_status)) {
		goto done;
	}

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

	TALLOC_FREE(sampass);

	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)->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:
	TALLOC_FREE(sampass);
	data_blob_free(&user_sess_key);
	data_blob_free(&lm_sess_key);
	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;
}