%%%-------------------------------------------------------------------
%%% @author Evgeny Khramtsov <ekhramtsov@process-one.net>
%%% Created : 4 Mar 2017 by Evgeny Khramtsov <ekhramtsov@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2017 ProcessOne
%%%
%%% 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 2 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, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%-------------------------------------------------------------------
-module(ejabberd_pkix).
-behaviour(gen_server).
-behaviour(ejabberd_config).
%% API
-export([start_link/0, add_certfile/1, format_error/1, opt_type/1,
get_certfile/1, try_certfile/1, route_registered/1]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-include_lib("public_key/include/public_key.hrl").
-include("logger.hrl").
-include("jid.hrl").
-record(state, {validate = true :: boolean(),
certs = #{}}).
-record(cert_state, {domains = [] :: [binary()]}).
-type cert() :: #'OTPCertificate'{}.
-type priv_key() :: public_key:private_key().
-type pub_key() :: #'RSAPublicKey'{} | {integer(), #'Dss-Parms'{}} | #'ECPoint'{}.
-type bad_cert_reason() :: cert_expired | invalid_issuer | invalid_signature |
name_not_permitted | missing_basic_constraint |
invalid_key_usage | selfsigned_peer | unknown_sig_algo |
unknown_ca | missing_priv_key.
-type bad_cert() :: {bad_cert, bad_cert_reason()}.
-type cert_error() :: not_cert | not_der | not_pem | encrypted.
-export_type([cert_error/0]).
%%%===================================================================
%%% API
%%%===================================================================
-spec add_certfile(filename:filename())
-> ok | {error, cert_error() | file:posix()}.
add_certfile(Path) ->
gen_server:call(?MODULE, {add_certfile, prep_path(Path)}).
-spec try_certfile(filename:filename()) -> binary().
try_certfile(Path0) ->
Path = prep_path(Path0),
case mk_cert_state(Path, false) of
{ok, _} -> Path;
{error, _} -> erlang:error(badarg)
end.
route_registered(Route) ->
gen_server:call(?MODULE, {route_registered, Route}).
-spec format_error(cert_error() | file:posix()) -> string().
format_error(not_cert) ->
"no PEM encoded certificates found";
format_error(not_pem) ->
"failed to decode from PEM format";
format_error(not_der) ->
"failed to decode from DER format";
format_error(encrypted) ->
"encrypted certificate found in the chain";
format_error({bad_cert, cert_expired}) ->
"certificate is no longer valid as its expiration date has passed";
format_error({bad_cert, invalid_issuer}) ->
"certificate issuer name does not match the name of the "
"issuer certificate in the chain";
format_error({bad_cert, invalid_signature}) ->
"certificate was not signed by its issuer certificate in the chain";
format_error({bad_cert, name_not_permitted}) ->
"invalid Subject Alternative Name extension";
format_error({bad_cert, missing_basic_constraint}) ->
"certificate, required to have the basic constraints extension, "
"does not have a basic constraints extension";
format_error({bad_cert, invalid_key_usage}) ->
"certificate key is used in an invalid way according "
"to the key-usage extension";
format_error({bad_cert, selfsigned_peer}) ->
"self-signed certificate in the chain";
format_error({bad_cert, unknown_sig_algo}) ->
"certificate is signed using unknown algorithm";
format_error({bad_cert, unknown_ca}) ->
"certificate is signed by unknown CA";
format_error({bad_cert, missing_priv_key}) ->
"no matching private key found for certificate in the chain";
format_error({bad_cert, Unknown}) ->
lists:flatten(io_lib:format("~w", [Unknown]));
format_error(Why) ->
case file:format_error(Why) of
"unknown POSIX error" ->
atom_to_list(Why);
Reason ->
Reason
end.
-spec get_certfile(binary()) -> {ok, binary()} | error.
get_certfile(Domain) ->
case ejabberd_idna:domain_utf8_to_ascii(Domain) of
false ->
error;
ASCIIDomain ->
case ets:lookup(?MODULE, ASCIIDomain) of
[] ->
case binary:split(ASCIIDomain, <<".">>, [trim]) of
[_, Host] ->
case ets:lookup(?MODULE, <<"*.", Host/binary>>) of
[{_, Path}|_] ->
{ok, Path};
[] ->
error
end;
_ ->
error
end;
[{_, Path}|_] ->
{ok, Path}
end
end.
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
opt_type(ca_path) ->
fun(Path) -> iolist_to_binary(Path) end;
opt_type(_) ->
[ca_path].
%%%===================================================================
%%% gen_server callbacks
%%%===================================================================
init([]) ->
process_flag(trap_exit, true),
ets:new(?MODULE, [named_table, public, bag]),
ejabberd_hooks:add(route_registered, ?MODULE, route_registered, 50),
Validate = case os:type() of
{win32, _} -> false;
_ ->
code:ensure_loaded(public_key),
erlang:function_exported(
public_key, short_name_hash, 1)
end,
if Validate -> check_ca_dir();
true -> ok
end,
State = #state{validate = Validate},
{ok, add_certfiles(State)}.
handle_call({add_certfile, Path}, _, State) ->
{Result, NewState} = add_certfile(Path, State),
{reply, Result, NewState};
handle_call({route_registered, Host}, _, State) ->
NewState = add_certfiles(Host, State),
case get_certfile(Host) of
{ok, _} -> ok;
error ->
?WARNING_MSG("No certificate found matching '~s': strictly "
"configured clients or servers will reject "
"connections with this host", [Host])
end,
{reply, ok, NewState};
handle_call(_Request, _From, State) ->
Reply = ok,
{reply, Reply, State}.
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info(_Info, State) ->
?WARNING_MSG("unexpected info: ~p", [_Info]),
{noreply, State}.
terminate(_Reason, _State) ->
ejabberd_hooks:delete(route_registered, ?MODULE, route_registered, 50).
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%%===================================================================
%%% Internal functions
%%%===================================================================
add_certfiles(State) ->
lists:foldl(
fun(Host, AccState) ->
add_certfiles(Host, AccState)
end, State, ejabberd_config:get_myhosts()).
add_certfiles(Host, State) ->
lists:foldl(
fun(Opt, AccState) ->
case ejabberd_config:get_option({Opt, Host}) of
undefined -> AccState;
Path ->
{_, NewAccState} = add_certfile(Path, AccState),
NewAccState
end
end, State, [c2s_certfile, s2s_certfile, domain_certfile]).
add_certfile(Path, State) ->
case maps:get(Path, State#state.certs, undefined) of
#cert_state{} ->
{ok, State};
undefined ->
case mk_cert_state(Path, State#state.validate) of
{error, Reason} ->
{{error, Reason}, State};
{ok, CertState} ->
NewCerts = maps:put(Path, CertState, State#state.certs),
lists:foreach(
fun(Domain) ->
ets:insert(?MODULE, {Domain, Path})
end, CertState#cert_state.domains),
{ok, State#state{certs = NewCerts}}
end
end.
mk_cert_state(Path, Validate) ->
case check_certfile(Path, Validate) of
{ok, Ds} ->
{ok, #cert_state{domains = Ds}};
{invalid, Ds, {bad_cert, _} = Why} ->
?WARNING_MSG("certificate from ~s is invalid: ~s",
[Path, format_error(Why)]),
{ok, #cert_state{domains = Ds}};
{error, Why} = Err ->
?ERROR_MSG("failed to read certificate from ~s: ~s",
[Path, format_error(Why)]),
Err
end.
-spec check_certfile(filename:filename(), boolean())
-> {ok, [binary()]} | {invalid, [binary()], bad_cert()} |
{error, cert_error() | file:posix()}.
check_certfile(Path, Validate) ->
try
{ok, Data} = file:read_file(Path),
{ok, Certs, PrivKeys} = pem_decode(Data),
CertPaths = get_cert_paths(Certs),
Domains = get_domains(CertPaths),
case match_cert_keys(CertPaths, PrivKeys) of
{ok, _} ->
case validate(CertPaths, Validate) of
ok -> {ok, Domains};
{error, Why} -> {invalid, Domains, Why}
end;
{error, Why} ->
{invalid, Domains, Why}
end
catch _:{badmatch, {error, _} = Err} ->
Err
end.
-spec pem_decode(binary()) -> {ok, [cert()], [priv_key()]} |
{error, cert_error()}.
pem_decode(Data) ->
try public_key:pem_decode(Data) of
PemEntries ->
case decode_certs(PemEntries) of
{error, _} = Err ->
Err;
Objects ->
case lists:partition(
fun(#'OTPCertificate'{}) -> true;
(_) -> false
end, Objects) of
{[], _} ->
{error, not_cert};
{Certs, PrivKeys} ->
{ok, Certs, PrivKeys}
end
end
catch _:_ ->
{error, not_pem}
end.
-spec decode_certs([public_key:pem_entry()]) -> {[cert()], [priv_key()]} |
{error, not_der | encrypted}.
decode_certs(PemEntries) ->
try lists:foldr(
fun(_, {error, _} = Err) ->
Err;
({_, _, Flag}, _) when Flag /= not_encrypted ->
{error, encrypted};
({'Certificate', Der, _}, Acc) ->
[public_key:pkix_decode_cert(Der, otp)|Acc];
({'PrivateKeyInfo', Der, not_encrypted}, Acc) ->
#'PrivateKeyInfo'{privateKeyAlgorithm =
#'PrivateKeyInfo_privateKeyAlgorithm'{
algorithm = Algo},
privateKey = Key} =
public_key:der_decode('PrivateKeyInfo', Der),
case Algo of
?'rsaEncryption' ->
[public_key:der_decode(
'RSAPrivateKey', iolist_to_binary(Key))|Acc];
?'id-dsa' ->
[public_key:der_decode(
'DSAPrivateKey', iolist_to_binary(Key))|Acc];
?'id-ecPublicKey' ->
[public_key:der_decode(
'ECPrivateKey', iolist_to_binary(Key))|Acc];
_ ->
Acc
end;
({Tag, Der, _}, Acc) when Tag == 'RSAPrivateKey';
Tag == 'DSAPrivateKey';
Tag == 'ECPrivateKey' ->
[public_key:der_decode(Tag, Der)|Acc];
(_, Acc) ->
Acc
end, [], PemEntries)
catch _:_ ->
{error, not_der}
end.
-spec validate([{path, [cert()]}], boolean()) -> ok | {error, bad_cert()}.
validate([{path, Path}|Paths], true) ->
case validate_path(Path) of
ok ->
validate(Paths, true);
Err ->
Err
end;
validate(_, _) ->
ok.
-spec validate_path([cert()]) -> ok | {error, bad_cert()}.
validate_path([Cert|_] = Certs) ->
case find_local_issuer(Cert) of
{ok, IssuerCert} ->
try public_key:pkix_path_validation(IssuerCert, Certs, []) of
{ok, _} ->
ok;
Err ->
Err
catch error:function_clause ->
case erlang:get_stacktrace() of
[{public_key, pkix_sign_types, _, _}|_] ->
{error, {bad_cert, unknown_sig_algo}};
ST ->
%% Bug in public_key application
erlang:raise(error, function_clause, ST)
end
end;
{error, _} = Err ->
case public_key:pkix_is_self_signed(Cert) of
true ->
{error, {bad_cert, selfsigned_peer}};
false ->
Err
end
end.
-spec ca_dir() -> string().
ca_dir() ->
ejabberd_config:get_option(ca_path, "/etc/ssl/certs").
-spec check_ca_dir() -> ok.
check_ca_dir() ->
case filelib:wildcard(filename:join(ca_dir(), "*.0")) of
[] ->
Hint = "configuring 'ca_path' option might help",
case file:list_dir(ca_dir()) of
{error, Why} ->
?WARNING_MSG("failed to read CA directory ~s: ~s; ~s",
[ca_dir(), file:format_error(Why), Hint]);
{ok, _} ->
?WARNING_MSG("CA directory ~s doesn't contain "
"hashed certificate files; ~s",
[ca_dir(), Hint])
end;
_ ->
ok
end.
-spec find_local_issuer(cert()) -> {ok, cert()} | {error, {bad_cert, unknown_ca}}.
find_local_issuer(Cert) ->
{ok, {_, IssuerID}} = public_key:pkix_issuer_id(Cert, self),
Hash = short_name_hash(IssuerID),
filelib:fold_files(
ca_dir(), Hash ++ "\\.[0-9]+", false,
fun(_, {ok, IssuerCert}) ->
{ok, IssuerCert};
(CertFile, Acc) ->
try
{ok, Data} = file:read_file(CertFile),
{ok, [IssuerCert|_], _} = pem_decode(Data),
case public_key:pkix_is_issuer(Cert, IssuerCert) of
true ->
{ok, IssuerCert};
false ->
Acc
end
catch _:{badmatch, {error, Why}} ->
?ERROR_MSG("failed to read CA certificate from \"~s\": ~s",
[CertFile, format_error(Why)]),
Acc
end
end, {error, {bad_cert, unknown_ca}}).
-spec match_cert_keys([{path, [cert()]}], [priv_key()])
-> {ok, [{cert(), priv_key()}]} | {error, {bad_cert, missing_priv_key}}.
match_cert_keys(CertPaths, PrivKeys) ->
KeyPairs = [{pubkey_from_privkey(PrivKey), PrivKey} || PrivKey <- PrivKeys],
match_cert_keys(CertPaths, KeyPairs, []).
-spec match_cert_keys([{path, [cert()]}], [{pub_key(), priv_key()}],
[{cert(), priv_key()}])
-> {ok, [{cert(), priv_key()}]} | {error, {bad_cert, missing_priv_key}}.
match_cert_keys([{path, Certs}|CertPaths], KeyPairs, Result) ->
[Cert|_] = RevCerts = lists:reverse(Certs),
PubKey = pubkey_from_cert(Cert),
case lists:keyfind(PubKey, 1, KeyPairs) of
false ->
{error, {bad_cert, missing_priv_key}};
{_, PrivKey} ->
match_cert_keys(CertPaths, KeyPairs, [{RevCerts, PrivKey}|Result])
end;
match_cert_keys([], _, Result) ->
{ok, Result}.
-spec pubkey_from_cert(cert()) -> pub_key().
pubkey_from_cert(Cert) ->
TBSCert = Cert#'OTPCertificate'.tbsCertificate,
PubKeyInfo = TBSCert#'OTPTBSCertificate'.subjectPublicKeyInfo,
SubjPubKey = PubKeyInfo#'OTPSubjectPublicKeyInfo'.subjectPublicKey,
case PubKeyInfo#'OTPSubjectPublicKeyInfo'.algorithm of
#'PublicKeyAlgorithm'{
algorithm = ?rsaEncryption} ->
SubjPubKey;
#'PublicKeyAlgorithm'{
algorithm = ?'id-dsa',
parameters = {params, DSSParams}} ->
{SubjPubKey, DSSParams};
#'PublicKeyAlgorithm'{
algorithm = ?'id-ecPublicKey'} ->
SubjPubKey
end.
-spec pubkey_from_privkey(priv_key()) -> pub_key().
pubkey_from_privkey(#'RSAPrivateKey'{modulus = Modulus,
publicExponent = Exp}) ->
#'RSAPublicKey'{modulus = Modulus,
publicExponent = Exp};
pubkey_from_privkey(#'DSAPrivateKey'{p = P, q = Q, g = G, y = Y}) ->
{Y, #'Dss-Parms'{p = P, q = Q, g = G}};
pubkey_from_privkey(#'ECPrivateKey'{publicKey = Key}) ->
#'ECPoint'{point = Key}.
-spec get_domains([{path, [cert()]}]) -> [binary()].
get_domains(CertPaths) ->
lists:usort(
lists:flatmap(
fun({path, Certs}) ->
Cert = lists:last(Certs),
xmpp_stream_pkix:get_cert_domains(Cert)
end, CertPaths)).
-spec get_cert_paths([cert()]) -> [{path, [cert()]}].
get_cert_paths(Certs) ->
G = digraph:new([acyclic]),
lists:foreach(
fun(Cert) ->
digraph:add_vertex(G, Cert)
end, Certs),
lists:foreach(
fun({Cert1, Cert2}) when Cert1 /= Cert2 ->
case public_key:pkix_is_issuer(Cert1, Cert2) of
true ->
digraph:add_edge(G, Cert1, Cert2);
false ->
ok
end;
(_) ->
ok
end, [{Cert1, Cert2} || Cert1 <- Certs, Cert2 <- Certs]),
Paths = lists:flatmap(
fun(Cert) ->
case digraph:in_degree(G, Cert) of
0 ->
get_cert_path(G, [Cert]);
_ ->
[]
end
end, Certs),
digraph:delete(G),
Paths.
get_cert_path(G, [Root|_] = Acc) ->
case digraph:out_edges(G, Root) of
[] ->
[{path, Acc}];
Es ->
lists:flatmap(
fun(E) ->
{_, _, V, _} = digraph:edge(G, E),
get_cert_path(G, [V|Acc])
end, Es)
end.
-spec prep_path(filename:filename()) -> binary().
prep_path(Path0) ->
case filename:pathtype(Path0) of
relative ->
{ok, CWD} = file:get_cwd(),
iolist_to_binary(filename:join(CWD, Path0));
_ ->
iolist_to_binary(Path0)
end.
-ifdef(SHORT_NAME_HASH).
short_name_hash(IssuerID) ->
public_key:short_name_hash(IssuerID).
-else.
short_name_hash(_) ->
"".
-endif.
