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Editing: AuthDatabase.Lua.txt
Lua based authentication ======================== Since v2.3.0 you can implement passdb and userdb using Lua [https://www.lua.org/] script. Contents 1. Lua based authentication 1. Known bugs 2. Lua interface 3. Auth request methods 4. Password database 5. User database 6. Examples Known bugs ---------- * Before 2.3.4 when returning a table with values, the table values are mistakenly converted into a number if they seem like a number. So if you are using values like '012345', this would get converted into '12345' * Before 2.3.4 returning password without scheme would cause a crash. Lua interface ------------- For details about Dovecot Lua, see <Design.Lua.txt>. When used in authentication, additional module *dovecot.auth* is added, which contains constants for passdb and userdb. List of constants ----------------- * dovecot.auth.PASSDB_RESULT_INTERNAL_FAILURE * dovecot.auth.PASSDB_RESULT_SCHEME_NOT_AVAILABLE - indicates password scheme that cannot be understood * dovecot.auth.PASSDB_RESULT_USER_UNKNOWN * dovecot.auth.PASSDB_RESULT_USER_DISABLED * dovecot.auth.PASSDB_RESULT_PASS_EXPIRED * dovecot.auth.PASSDB_RESULT_NEXT - indicates that this passdb did not authenticate user, next passdb should do it * dovecot.auth.PASSDB_RESULT_PASSWORD_MISMATCH * dovecot.auth.PASSDB_RESULT_OK * dovecot.auth.USERDB_RESULT_INTERNAL_FAILURE * dovecot.auth.USERDB_RESULT_USER_UNKNOWN * dovecot.auth.USERDB_RESULT_OK Also, it registers object *struct auth_request** which lets access various parts of the auth request. You should use the loggers associated with auth_request when possible. Auth request methods -------------------- Functions: * auth_request#log_debug(text) - logs debug message (if debug is enabled, noop otherwise) * auth_request#log_error(text) - logs error message * auth_request#log_info(text) - logs informational message * auth_request#log_warning(text) - logs warning message * auth_request#response_from_template(template) - takes in key=value template and expands it using var_expand and produces table suitable for passdb result * auth_request#var_expand(template) - performs var expansion on the template using <Variables.txt> * auth_request#password_verify(crypted_password, plain_password) - checks if the plain password matches the crypted or hashed password * auth_request#event() - Returns child event for the auth request, can be used for logging and other events. Comes with a prefix. (Since v2.3.6+) Subtables: * auth_request#passdb * auth_request#userdb Members: See <Variables.txt> for details * auth_request#auth_domain * auth_request#auth_user * auth_request#auth_username * auth_request#cert * auth_request#client_id * auth_request#domain * auth_request#domain_first * auth_request#domain_last * auth_request#home * auth_request#lip * auth_request#local_name * auth_request#login_domain * auth_request#login_user * auth_request#login_username * auth_request#lport * auth_request#master_user * auth_request#mech * auth_request#orig_domain * auth_request#orig_user * auth_request#orig_username * auth_request#password * auth_request#pid * auth_request#real_lip * auth_request#real_lport * auth_request#real_rip * auth_request#real_rport * auth_request#rip * auth_request#rport * auth_request#secured * auth_request#service * auth_request#session * auth_request#session_pid * auth_request#user * auth_request#username Additionally you can access * skip_password_check - Set if the password has already been validated by another passdb * passdbs_seen_user_unknown - If some previous passdb has not found this user * passdbs_seen_internal_failure - If some previous passdb has had internal failure * userdbs_seen_internal_failure - If some previous userdb has had internal failure Password database ----------------- Lua passdb supports two modes of function. It can behave as lookup database, or password verification database. Lookup function signature is *auth_passdb_lookup(request)* and the password verification signature is *auth_password_verify(request, password)* Both functions must return a tuple, which contains a return code, and also additionally string or table. Table must be in key-value format, it will be imported into auth request. The string must be in key=value format, except if return code indicates internal error, the second parameter can be used as error string. If *auth_verify_password* is found, it's always used. To configure passdb in dovecot, use ---%<------------------------------------------------------------------------- passdb { driver = lua args = file=/path/to/lua blocking=yes # default is yes } ---%<------------------------------------------------------------------------- By default, dovecot runs Lua scripts in auth-worker processes. If you do not want this, you can disable blocking, and Lua script will be ran in auth process. This can degrade performance if your script is slow or makes external lookups. User database ------------- Lua userdb supports both single user lookup and iteration. Note that iteration will hold the whole user database in memory during iteration. User lookup function signature is *auth_userdb_lookup(request)*. The function must return a tuple, which contains a return code, and also additionally string or table. Table must be in key-value format, it will be imported into auth request. The string must be in key=value format, except if return code indicates internal error, the second parameter can be used as error string. User iteration function signature is *auth_userdb_iterate*, which is expected to return table of usernames. Key names are ignored. To configure userdb in dovecot, use ---%<------------------------------------------------------------------------- userdb { driver = lua args = file=/path/to/lua blocking=yes # default is yes } ---%<------------------------------------------------------------------------- Examples -------- Skeleton -------- ---%<------------------------------------------------------------------------- function auth_passdb_lookup(req) if req.user == "testuser1" then return dovecot.auth.PASSDB_RESULT_OK, "password=pass" end return dovecot.auth.PASSDB_RESULT_USER_UNKNOWN, "no such user" end function auth_userdb_lookup(req) if req.user == "testuser1" then return dovecot.auth.USERDB_RESULT_OK, "uid=vmail gid=vmail" end return dovecot.auth.USERDB_RESULT_USER_UNKNOWN, "no such user" end function script_init() return 0 end function script_deinit() end function auth_userdb_iterate() return {"testuser1"} end ---%<------------------------------------------------------------------------- Simple username password database (such as opensmtpd) ----------------------------------------------------- The example uses whitespace separated username and password. As a special caution, the way Lua is used here means you can have multiple user password per line, instead of just one.This can be extended to more complicated separators or multiple fields per user. If you only want to autenticate users, and don't care about user listing, you can use ---%<------------------------------------------------------------------------- function auth_passdb_lookup(req) for line in io.lines("/path/to/file") do for user, pass in string.gmatch(line, "(%w+)%s(.+)") do if (user == req.username) then -- you can add additional information here, like userdb_uid return dovecot.auth.PASSDB_RESULT_OK, "password=" .. pass end end end return dovecot.auth.PASSDB_RESULT_USER_UNKNOWN, "" end ---%<------------------------------------------------------------------------- If you also want to be able to list users, so that you could use doveadm cmd -A ---%<------------------------------------------------------------------------- local database = "/path/to/file" function db_lookup(username) for line in io.lines(database) do for user, pass in string.gmatch(line, "(%w+)%s(.+)") do if (user == username) then return {result=0, password=pass} end end end return {result=-1} end function auth_passdb_lookup(req) res = db_lookup(req.username) if res.result == 0 then -- you can add additional information here for passdb return dovecot.auth.PASSDB_RESULT_OK, "password=" .. res.password end return dovecot.auth.PASSDB_RESULT_USER_UNKNOWN, "" end function auth_userdb_lookup(req) res = db_lookup(req.username) if res.result == 0 then -- you can add additional information here for userdb, like uid or home return dovecot.auth.USERDB_RESULT_OK, "uid=vmail gid=vmail" end return dovecot.auth.USERDB_RESULT_USER_UNKNOWN, "" end function auth_userdb_iterate() users = {} for line in io.lines(database) do for user in string.gmatch(line, "(%w+)%s.+") do table.insert(users, user) end end return users end ---%<------------------------------------------------------------------------- (This file was created from the wiki on 2019-06-19 12:42)
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