mirror of
https://github.com/processone/ejabberd.git
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272 lines
9.2 KiB
Erlang
272 lines
9.2 KiB
Erlang
%%%----------------------------------------------------------------------
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%%% File : cyrsasl_digest.erl
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%%% Author : Alexey Shchepin <alexey@sevcom.net>
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%%% Purpose : DIGEST-MD5 SASL mechanism
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%%% Created : 11 Mar 2003 by Alexey Shchepin <alexey@sevcom.net>
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%%%
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%%%
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%%% ejabberd, Copyright (C) 2002-2017 ProcessOne
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%%%
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%%% This program is free software; you can redistribute it and/or
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%%% modify it under the terms of the GNU General Public License as
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%%% published by the Free Software Foundation; either version 2 of the
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%%% License, or (at your option) any later version.
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%%%
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%%% This program is distributed in the hope that it will be useful,
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%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
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%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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%%% General Public License for more details.
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%%%
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%%% You should have received a copy of the GNU General Public License along
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%%% with this program; if not, write to the Free Software Foundation, Inc.,
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%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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%%%
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%%%----------------------------------------------------------------------
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-module(cyrsasl_digest).
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-behaviour(ejabberd_config).
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-author('alexey@sevcom.net').
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-export([start/1, stop/0, mech_new/4, mech_step/2,
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parse/1, format_error/1, opt_type/1]).
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-include("ejabberd.hrl").
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-include("logger.hrl").
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-behaviour(cyrsasl).
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-type get_password_fun() :: fun((binary()) -> {false, any()} |
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{binary(), atom()}).
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-type check_password_fun() :: fun((binary(), binary(), binary(), binary(),
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fun((binary()) -> binary())) ->
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{boolean(), any()} |
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false).
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-type error_reason() :: parser_failed | invalid_digest_uri |
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not_authorized | unexpected_response.
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-export_type([error_reason/0]).
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-record(state, {step = 1 :: 1 | 3 | 5,
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nonce = <<"">> :: binary(),
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username = <<"">> :: binary(),
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authzid = <<"">> :: binary(),
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get_password :: get_password_fun(),
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check_password :: check_password_fun(),
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auth_module :: atom(),
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host = <<"">> :: binary(),
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hostfqdn = [] :: [binary()]}).
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start(_Opts) ->
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Fqdn = get_local_fqdn(),
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?INFO_MSG("FQDN used to check DIGEST-MD5 SASL authentication: ~s",
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[Fqdn]),
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cyrsasl:register_mechanism(<<"DIGEST-MD5">>, ?MODULE,
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digest).
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stop() -> ok.
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-spec format_error(error_reason()) -> {atom(), binary()}.
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format_error(parser_failed) ->
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{'bad-protocol', <<"Response decoding failed">>};
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format_error(invalid_digest_uri) ->
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{'bad-protocol', <<"Invalid digest URI">>};
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format_error(not_authorized) ->
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{'not-authorized', <<"Invalid username or password">>};
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format_error(unexpected_response) ->
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{'bad-protocol', <<"Unexpected response">>}.
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mech_new(Host, GetPassword, _CheckPassword,
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CheckPasswordDigest) ->
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{ok,
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#state{step = 1, nonce = randoms:get_string(),
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host = Host, hostfqdn = get_local_fqdn(),
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get_password = GetPassword,
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check_password = CheckPasswordDigest}}.
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mech_step(#state{step = 1, nonce = Nonce} = State, _) ->
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{continue,
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<<"nonce=\"", Nonce/binary,
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"\",qop=\"auth\",charset=utf-8,algorithm=md5-sess">>,
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State#state{step = 3}};
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mech_step(#state{step = 3, nonce = Nonce} = State,
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ClientIn) ->
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case parse(ClientIn) of
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bad -> {error, parser_failed};
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KeyVals ->
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DigestURI = proplists:get_value(<<"digest-uri">>, KeyVals, <<>>),
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UserName = proplists:get_value(<<"username">>, KeyVals, <<>>),
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case is_digesturi_valid(DigestURI, State#state.host,
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State#state.hostfqdn)
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of
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false ->
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?DEBUG("User login not authorized because digest-uri "
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"seems invalid: ~p (checking for Host "
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"~p, FQDN ~p)",
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[DigestURI, State#state.host, State#state.hostfqdn]),
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{error, invalid_digest_uri, UserName};
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true ->
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AuthzId = proplists:get_value(<<"authzid">>, KeyVals, <<>>),
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case (State#state.get_password)(UserName) of
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{false, _} -> {error, not_authorized, UserName};
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{Passwd, AuthModule} ->
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case (State#state.check_password)(UserName, UserName, <<"">>,
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proplists:get_value(<<"response">>, KeyVals, <<>>),
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fun (PW) ->
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response(KeyVals,
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UserName,
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PW,
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Nonce,
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AuthzId,
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<<"AUTHENTICATE">>)
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end)
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of
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{true, _} ->
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RspAuth = response(KeyVals, UserName, Passwd, Nonce,
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AuthzId, <<"">>),
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{continue, <<"rspauth=", RspAuth/binary>>,
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State#state{step = 5, auth_module = AuthModule,
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username = UserName,
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authzid = AuthzId}};
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false -> {error, not_authorized, UserName};
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{false, _} -> {error, not_authorized, UserName}
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end
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end
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end
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end;
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mech_step(#state{step = 5, auth_module = AuthModule,
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username = UserName, authzid = AuthzId},
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<<"">>) ->
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{ok,
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[{username, UserName}, {authzid, case AuthzId of
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<<"">> -> UserName;
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_ -> AuthzId
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end
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},
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{auth_module, AuthModule}]};
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mech_step(A, B) ->
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?DEBUG("SASL DIGEST: A ~p B ~p", [A, B]),
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{error, unexpected_response}.
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parse(S) -> parse1(binary_to_list(S), "", []).
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parse1([$= | Cs], S, Ts) ->
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parse2(Cs, lists:reverse(S), "", Ts);
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parse1([$, | Cs], [], Ts) -> parse1(Cs, [], Ts);
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parse1([$\s | Cs], [], Ts) -> parse1(Cs, [], Ts);
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parse1([C | Cs], S, Ts) -> parse1(Cs, [C | S], Ts);
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parse1([], [], T) -> lists:reverse(T);
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parse1([], _S, _T) -> bad.
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parse2([$" | Cs], Key, Val, Ts) ->
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parse3(Cs, Key, Val, Ts);
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parse2([C | Cs], Key, Val, Ts) ->
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parse4(Cs, Key, [C | Val], Ts);
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parse2([], _, _, _) -> bad.
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parse3([$" | Cs], Key, Val, Ts) ->
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parse4(Cs, Key, Val, Ts);
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parse3([$\\, C | Cs], Key, Val, Ts) ->
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parse3(Cs, Key, [C | Val], Ts);
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parse3([C | Cs], Key, Val, Ts) ->
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parse3(Cs, Key, [C | Val], Ts);
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parse3([], _, _, _) -> bad.
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parse4([$, | Cs], Key, Val, Ts) ->
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parse1(Cs, "", [{list_to_binary(Key), list_to_binary(lists:reverse(Val))} | Ts]);
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parse4([$\s | Cs], Key, Val, Ts) ->
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parse4(Cs, Key, Val, Ts);
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parse4([C | Cs], Key, Val, Ts) ->
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parse4(Cs, Key, [C | Val], Ts);
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parse4([], Key, Val, Ts) ->
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%% @doc Check if the digest-uri is valid.
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%% RFC-2831 allows to provide the IP address in Host,
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%% however ejabberd doesn't allow that.
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%% If the service (for example jabber.example.org)
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%% is provided by several hosts (being one of them server3.example.org),
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%% then acceptable digest-uris would be:
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%% xmpp/server3.example.org/jabber.example.org, xmpp/server3.example.org and
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%% xmpp/jabber.example.org
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%% The last version is not actually allowed by the RFC, but implemented by popular clients
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parse1([], "", [{list_to_binary(Key), list_to_binary(lists:reverse(Val))} | Ts]).
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is_digesturi_valid(DigestURICase, JabberDomain,
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JabberFQDN) ->
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DigestURI = stringprep:tolower(DigestURICase),
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case catch str:tokens(DigestURI, <<"/">>) of
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[<<"xmpp">>, Host] ->
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IsHostFqdn = is_host_fqdn(Host, JabberFQDN),
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(Host == JabberDomain) or IsHostFqdn;
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[<<"xmpp">>, Host, ServName] ->
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IsHostFqdn = is_host_fqdn(Host, JabberFQDN),
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(ServName == JabberDomain) and IsHostFqdn;
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_ ->
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false
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end.
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is_host_fqdn(_Host, []) ->
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false;
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is_host_fqdn(Host, [Fqdn | _FqdnTail]) when Host == Fqdn ->
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true;
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is_host_fqdn(Host, [Fqdn | FqdnTail]) when Host /= Fqdn ->
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is_host_fqdn(Host, FqdnTail).
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get_local_fqdn() ->
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case ejabberd_config:get_option(fqdn) of
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undefined ->
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{ok, Hostname} = inet:gethostname(),
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{ok, {hostent, Fqdn, _, _, _, _}} = inet:gethostbyname(Hostname),
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[list_to_binary(Fqdn)];
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Fqdn ->
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Fqdn
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end.
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hex(S) ->
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str:to_hexlist(S).
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proplists_get_bin_value(Key, Pairs, Default) ->
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case proplists:get_value(Key, Pairs, Default) of
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L when is_list(L) ->
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list_to_binary(L);
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L2 ->
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L2
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end.
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response(KeyVals, User, Passwd, Nonce, AuthzId,
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A2Prefix) ->
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Realm = proplists_get_bin_value(<<"realm">>, KeyVals, <<>>),
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CNonce = proplists_get_bin_value(<<"cnonce">>, KeyVals, <<>>),
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DigestURI = proplists_get_bin_value(<<"digest-uri">>, KeyVals, <<>>),
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NC = proplists_get_bin_value(<<"nc">>, KeyVals, <<>>),
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QOP = proplists_get_bin_value(<<"qop">>, KeyVals, <<>>),
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MD5Hash = erlang:md5(<<User/binary, ":", Realm/binary, ":",
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Passwd/binary>>),
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A1 = case AuthzId of
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<<"">> ->
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<<MD5Hash/binary, ":", Nonce/binary, ":", CNonce/binary>>;
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_ ->
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<<MD5Hash/binary, ":", Nonce/binary, ":", CNonce/binary, ":",
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AuthzId/binary>>
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end,
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A2 = case QOP of
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<<"auth">> ->
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<<A2Prefix/binary, ":", DigestURI/binary>>;
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_ ->
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<<A2Prefix/binary, ":", DigestURI/binary,
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":00000000000000000000000000000000">>
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end,
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T = <<(hex((erlang:md5(A1))))/binary, ":", Nonce/binary,
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":", NC/binary, ":", CNonce/binary, ":", QOP/binary,
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":", (hex((erlang:md5(A2))))/binary>>,
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hex((erlang:md5(T))).
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-spec opt_type(fqdn) -> fun((binary() | [binary()]) -> [binary()]);
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(atom()) -> [atom()].
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opt_type(fqdn) ->
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fun(FQDN) when is_binary(FQDN) ->
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[FQDN];
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(FQDNs) when is_list(FQDNs) ->
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[iolist_to_binary(FQDN) || FQDN <- FQDNs]
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end;
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opt_type(_) -> [fqdn].
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