rnewson commented on code in PR #6069: URL: https://github.com/apache/couchdb/pull/6069#discussion_r4132730423
########## src/couch_replicator/src/couch_replicator_auth_ibm.erl: ########## @@ -0,0 +1,719 @@ +% Licensed under the Apache License, Version 2.0 (the "License"); you may not +% use this file except in compliance with the License. You may obtain a copy of +% the License at +% +% http://www.apache.org/licenses/LICENSE-2.0 +% +% Unless required by applicable law or agreed to in writing, software +% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +% License for the specific language governing permissions and limitations under +% the License. + +% This module allows a replication source or target to use an IAM api key for authentication. +% +% Features; +% +% Automatic refreshing of time-limited token before expiration +% Deduplication - only one token will be acquired for each distinct IAM api key +% +% Implementation details +% +% As api keys are sensitive, the only copy of api keys is held in a private ETS table +% owned by this module's gen_server. An opaque reference is returned to clients (this is +% a message authentication code where the key is a non-persisted value generated by the +% gen_server) + +-module(couch_replicator_auth_ibm). + +-behaviour(couch_replicator_auth). +-behaviour(gen_server). +-behaviour(config_listener). + +-export([ + sup_initialize/0, + sup_cleanup/1, + initialize/1, + update_headers/2, + handle_response/3, + cleanup/1 +]). + +%% gen_server callbacks +-export([ + init/1, + handle_call/3, + handle_cast/2, + handle_info/2, + terminate/2 +]). + +% config_listener callbacks +-export([ + handle_config_change/5, + handle_config_terminate/3 +]). + +-include_lib("couch_replicator/include/couch_replicator_api_wrap.hrl"). + +-define(MINUTE, 60). +-define(PUBLIC, couch_replicator_auth_ibm_public). +-define(PRIVATE, couch_replicator_auth_ibm_private). + +-record(worker_state, { + api_key_mac, + last_used +}). + +-record(state, { + mac_key, + token_url +}). + +-record(public_entry, { + api_key_mac, + token +}). + +-record(private_entry, { + api_key_mac, + api_key_uuid, + api_key, + % Number of seconds (counted since January 1st, 1970) until the IAM access token will expire. + expires_at_secs, + acquire_mref, + last_used, + last_updated, + waiters = [] +}). + +%% callbacks + +sup_initialize() -> + {ok, _} = gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). + +sup_cleanup(_) -> + ok = gen_server:stop(?MODULE). + +initialize(#httpdb{} = HttpDb) -> + case extract_api_key(HttpDb) of + {ok, APIKey} -> + case gen_server:call(?MODULE, {register, APIKey}) of + {ok, APIKeyMAC} -> + WorkerState = #worker_state{api_key_mac = APIKeyMAC, last_used = now_secs()}, + {ok, HttpDb, WorkerState}; + {error, Reason} -> + {error, Reason} + end; + {error, _} -> + ignore + end. + +update_headers(WorkerState, Headers) when is_list(Headers) -> + case get_token(WorkerState) of + {ok, Token} -> + { + [{~"Authorization", <<"Bearer ", Token/binary>>} | Headers], + update_last_used(WorkerState) + }; + {error, Reason} -> + couch_log:warning("Error when retrieving token: ~p", [Reason]), + {Headers, WorkerState} + end. + +handle_response(WorkerState, _StatusCode, _Headers) -> + {continue, WorkerState}. + +cleanup(_WorkerState) -> + ok. + +get_token(#worker_state{} = WorkerState) -> + #worker_state{api_key_mac = APIKeyMAC} = WorkerState, + case ets:lookup(?PUBLIC, APIKeyMAC) of + [#public_entry{token = Token}] when is_binary(Token) -> + {ok, Token}; + [#public_entry{}] -> + gen_server:call(?MODULE, {get_token, APIKeyMAC}, request_timeout_ms()); + [] -> + {error, no_token} + end. + +update_last_used(#worker_state{} = WorkerState) -> + #worker_state{api_key_mac = APIKeyMAC, last_used = LastUsed} = WorkerState, + Now = now_secs(), + %% only send a message once per minute at most. + case Now - LastUsed > ?MINUTE of + true -> + gen_server:cast(?MODULE, {update_last_used, APIKeyMAC}), + WorkerState#worker_state{last_used = Now}; + false -> + WorkerState + end. + +%% gen_server callbacks. + +init(_) -> + case token_url() of + {ok, TokenUrl} -> + ?PUBLIC = ets:new(?PUBLIC, [protected, {keypos, #public_entry.api_key_mac}, named_table]), + ?PRIVATE = ets:new(?PRIVATE, [ + private, {keypos, #private_entry.api_key_mac}, named_table + ]), + ok = config:listen_for_changes(?MODULE, nil), + erlang:send_after(check_interval_ms(), self(), refresh_expire_check), + {ok, #state{ + mac_key = crypto:strong_rand_bytes(32), + token_url = TokenUrl + }}; + {error, Reason} -> + {error, Reason} + end. + +handle_call({register, APIKey}, _From, State) -> + case ets:match_object(?PRIVATE, #private_entry{api_key = APIKey, _ = '_'}) of + [#private_entry{} = Entry] -> + {reply, {ok, Entry#private_entry.api_key_mac}, State}; + [] -> + AcquireMRef = acquire_token(APIKey, State), + APIKeyMAC = mac(State#state.mac_key, APIKey), + true = ets:insert_new(?PUBLIC, #public_entry{ + api_key_mac = APIKeyMAC + }), + NowSecs = now_secs(), + true = ets:insert_new(?PRIVATE, #private_entry{ + api_key = APIKey, + api_key_mac = APIKeyMAC, + acquire_mref = AcquireMRef, + last_used = NowSecs, + last_updated = NowSecs + }), + {reply, {ok, APIKeyMAC}, State} + end; +handle_call({get_token, APIKeyMAC}, From, State) -> + case ets:lookup(?PUBLIC, APIKeyMAC) of + [] -> + {reply, {error, no_such_api_key}, State}; + [#public_entry{token = Token}] when Token /= undefined -> + {reply, {ok, Token}, State}; + [#public_entry{}] -> + [#private_entry{} = Entry] = ets:lookup(?PRIVATE, APIKeyMAC), + ets:insert(?PRIVATE, Entry#private_entry{waiters = [From | Entry#private_entry.waiters]}), + if + Entry#private_entry.acquire_mref /= undefined -> + ok; + true -> + self() ! {refresh_token, APIKeyMAC} + end, + {noreply, State} + end; +handle_call(_Msg, _From, State) -> + {reply, {error, unexpected_msg}, State}. + +handle_cast({update_last_used, APIKeyMAC}, State) -> + ets:update_element(?PRIVATE, APIKeyMAC, {#private_entry.last_used, now_secs()}), + {noreply, State}; +handle_cast(_Msg, State) -> + {noreply, State}. + +handle_info({refresh_token, APIKeyMAC}, State) -> + case ets:lookup(?PRIVATE, APIKeyMAC) of + [] -> + ok; + [#private_entry{acquire_mref = undefined} = Entry] -> + case Entry#private_entry.last_used >= Entry#private_entry.last_updated of + true -> + couch_log:notice("~p: refreshing api key ~s", [ + ?MODULE, Entry#private_entry.api_key_uuid + ]), + AcquireMRef = acquire_token(Entry#private_entry.api_key, State), + ets:insert(?PRIVATE, Entry#private_entry{acquire_mref = AcquireMRef}); + false -> + %% let it expire and free any waiters + reply_and_reset(Entry, {error, token_expiring}) + end; + [#private_entry{}] -> + ok + end, + {noreply, State}; +handle_info({expire_api_key_entry, APIKeyMAC}, State) -> + NowSecs = now_secs(), + case ets:lookup(?PRIVATE, APIKeyMAC) of + [] -> + ok; + [#private_entry{expires_at_secs = ExpiresAtSecs} = Entry] when ExpiresAtSecs =< NowSecs -> + couch_log:warning("~p: api key entry ~s passed expiration time", [ + ?MODULE, Entry#private_entry.api_key_uuid + ]), + ets:delete(?PUBLIC, APIKeyMAC), + ets:delete(?PRIVATE, APIKeyMAC), + if + Entry#private_entry.acquire_mref /= undefined -> + demonitor(Entry#private_entry.acquire_mref, [flush]); + true -> + ok + end, + reply_all(Entry#private_entry.waiters, {error, expired_api_key_entry}); + % was refreshed + [#private_entry{}] -> + ok + end, + {noreply, State}; +handle_info(refresh_expire_check, #state{} = State) -> + NowSecs = now_secs(), + EarlyRefreshSecs = early_refresh_secs(), + Matches = ets:select(?PRIVATE, [ + { + #private_entry{api_key_mac = '$1', expires_at_secs = '$2', _ = '_'}, + [{is_integer, '$2'}, {'=<', '$2', NowSecs + EarlyRefreshSecs}], + [['$1', '$2']] + } + ]), + lists:foreach( + fun([APIKeyMAC, ExpiresAtSecs]) -> + if + NowSecs >= ExpiresAtSecs -> + self() ! {expire_api_key_entry, APIKeyMAC}; + true -> + erlang:send_after(jitter_ms(), self(), {refresh_token, APIKeyMAC}) + end + end, + Matches + ), + erlang:send_after(check_interval_ms(), self(), refresh_expire_check), + {noreply, State}; +handle_info( + {'DOWN', AcquireMRef, process, _AcquirePid, {ok, StatusCode, _ResponseHeaders, ResponseBody}}, + #state{} = State +) -> + case match_on_acquire_mref(AcquireMRef) of + [#private_entry{} = Entry] -> + case StatusCode of + 200 -> + case decode_iam_response(ResponseBody) of + {ok, Token, ExpiresAtSecs} -> + UUID = api_key_uuid(Token), + couch_log:notice("~p: refreshed api key ~s", [ + ?MODULE, UUID + ]), + true = ets:update_element(?PUBLIC, Entry#private_entry.api_key_mac, { + #public_entry.token, Token + }), + reply_and_reset( + Entry#private_entry{ + api_key_uuid = UUID, + expires_at_secs = ExpiresAtSecs, + last_updated = now_secs() + }, + {ok, Token} + ); + {error, Reason} -> + couch_log:notice("~p: failed to refresh api key ~s: ~p", [ + ?MODULE, Entry#private_entry.api_key_uuid, Reason + ]), + reply_and_reset(Entry, {error, Reason}) + end; + StatusCode -> + ErrorMessage = extract_error_message(ResponseBody), + couch_log:notice("~p: failed to refresh api key ~s: ~p", [ + ?MODULE, Entry#private_entry.api_key_uuid, ErrorMessage + ]), + case StatusCode of + 500 -> + erlang:send_after( + retry_ms(), + self(), + {refresh_token, Entry#private_entry.api_key_mac} + ); + _ -> + ok + end, + reply_and_reset(Entry, {error, ErrorMessage}) + end; + [] -> + ok + end, + {noreply, State}; +handle_info({'DOWN', AcquireMRef, process, _AcquirePid, Reason}, #state{} = State) -> + %% acquire process exited with {error, Reason} or died some other way + %% we don't care how, we always clean up after it + case match_on_acquire_mref(AcquireMRef) of + [#private_entry{} = Entry] -> + reply_and_reset(Entry, acquire_error(Reason)); + [] -> + ok + end, + {noreply, State}; +handle_info(restart_config_listener, State) -> + ok = config:listen_for_changes(?MODULE, nil), + {noreply, State}; +handle_info(token_url_change, State) -> + case token_url() of + {ok, TokenUrl} -> + %% picked up by the next request, nothing to reconnect + {noreply, State#state{token_url = TokenUrl}}; + {error, Reason} -> + {stop, Reason, State} + end; +handle_info(Msg, State) -> + couch_log:warning("~p: unexpected info ~p", [?MODULE, Msg]), + {noreply, State}. + +terminate(_Reason, _State) -> + ets:foldl( + fun(#private_entry{} = Entry, Acc) -> + lists:foreach( + fun(W) -> gen_server:reply(W, {error, terminated}) end, + Entry#private_entry.waiters + ), + Acc + end, + ok, + ?PRIVATE + ). + +%% config_listener functions. + +handle_config_change("replicator_auth_ibm", "token_url", _, _, State) -> + ?MODULE ! token_url_change, + {ok, State}; +handle_config_change(_, _, _, _, State) -> + {ok, State}. + +handle_config_terminate(_, stop, _) -> + ok; +handle_config_terminate(_Server, _Reason, _State) -> + erlang:send_after(5000, ?MODULE, restart_config_listener). + +%% private functions. + +now_secs() -> + erlang:system_time(second). + +extract_api_key(#httpdb{auth_props = AuthProps}) -> + case proplists:get_value(~"ibm", AuthProps) of + {IBMProps} when is_list(IBMProps) -> + case proplists:get_value(~"apikey", IBMProps) of + APIKey when is_binary(APIKey), byte_size(APIKey) > 0 -> + {ok, APIKey}; + _ -> + {error, missing_api_key} + end; + _ -> + {error, missing_api_key} + end. + +acquire_token(APIKey, #state{token_url = Url}) -> + Headers = [ + {~"content-type", ~"application/x-www-form-urlencoded"} + ], + Body = mochiweb_util:urlencode([ + {~"grant_type", ~"urn:ibm:params:oauth:grant-type:apikey"}, + {~"response_type", ~"cloud_iam"}, + {~"apikey", APIKey} + ]), + {_Pid, Ref} = spawn_monitor(fun() -> + exit( + try + post(Url, Headers, Body, request_timeout_ms()) + catch + Tag:Err -> {error, {Tag, Err}} + end + ) + end), + Ref. + +post(Url, ReqHeaders, ReqBody, Timeout) -> + Opts = #{ + timeout => Timeout, + tls_opts => [{cacerts, couch_replicator_utils:cacert_get()}] + }, + couch_gun:req(post, Url, ReqHeaders, ReqBody, Opts). + +decode_iam_response(ResponseBody) -> + try jiffy:decode(ResponseBody, [return_maps]) of + Decoded when is_map(Decoded) -> + Token = maps:get(~"access_token", Decoded, undefined), + ExpiresAtSecs = maps:get(~"expiration", Decoded, undefined), + if + is_binary(Token) andalso is_integer(ExpiresAtSecs) -> + {ok, Token, ExpiresAtSecs}; + true -> + {error, malformed_iam_response} + end; + _ -> + {error, malformed_iam_response} + catch + _:_ -> + {error, malformed_iam_response} + end. + +extract_error_message(ResponseBody) -> + try jiffy:decode(ResponseBody, [return_maps]) of + #{~"errorCode" := ErrorCode, ~"errorMessage" := ErrorMessage} -> + {ErrorCode, ErrorMessage}; + _ -> + malformed_iam_response + catch + _:_ -> + malformed_iam_response + end. + +api_key_uuid(EncodedToken) when is_binary(EncodedToken) -> + case binary:split(EncodedToken, ~".", [global]) of + [_Header, Payload, _Signature] -> + case b64url:decode(Payload) of + {error, _Reason} -> + ~""; + Decoded when is_binary(Decoded) -> + try jiffy:decode(Decoded, [return_maps]) of + #{~"apikey_uuid" := UUID} -> + UUID; + _ -> + ~"" + catch + _:_ -> + ~"" + end + end; + _ -> + ~"" + end. + +-spec token_url() -> {ok, string()} | {error, term()}. +token_url() -> + Url = config:get( + "replicator_auth_ibm", "token_url", "https://iam.cloud.ibm.com/identity/token"; + ), + case couch_gun:parse_url(Url) of + {ok, #{}} -> + {ok, Url}; + {error, Reason} -> + {error, Reason} + end. + +match_on_acquire_mref(AcquireMRef) -> + ets:match_object(?PRIVATE, #private_entry{acquire_mref = AcquireMRef, _ = '_'}). + +acquire_error({error, _} = Error) -> + Error; +acquire_error(Reason) -> + {error, Reason}. + +-spec reply_and_reset(Entry :: #private_entry{}, Reply :: term()) -> ok. +reply_and_reset(#private_entry{} = Entry, Reply) -> + ets:insert(?PRIVATE, Entry#private_entry{ + acquire_mref = undefined, + waiters = [] + }), + reply_all(Entry#private_entry.waiters, Reply). + +-spec reply_all(Waiters :: [gen_server:from()], Reply :: term()) -> ok. +reply_all(Waiters, Reply) -> + lists:foreach( + fun(W) -> gen_server:reply(W, Reply) end, + Waiters + ). + +mac(Key, Data) when is_binary(Key), is_binary(Data) -> + crypto:mac(hmac, sha256, Key, Data). + +request_timeout_ms() -> + max(0, 1000 * config:get_integer("replicator_auth_ibm", "request_timeout_secs", 30)). + +check_interval_ms() -> + max(0, 1000 * config:get_integer("replicator_auth_ibm", "check_interval_secs", 60)). + +early_refresh_secs() -> + max(0, config:get_integer("replicator_auth_ibm", "early_refresh_secs", 300)). + +jitter_ms() -> + JitterMS = max(0, 1000 * config:get_integer("replicator_auth_ibm", "jitter_secs", 60)), Review Comment: fixed -- This is an automated message from the Apache Git Service. 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