%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2005-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%%% Description: SSH file handling
-module(ssh_file).
-behaviour(ssh_key_api).
-include_lib("public_key/include/public_key.hrl").
-include_lib("kernel/include/file.hrl").
-include("ssh.hrl").
-export([host_key/2,
user_key/2,
is_host_key/4,
add_host_key/3,
is_auth_key/4]).
-define(PERM_700, 8#700).
-define(PERM_644, 8#644).
%% API
%% Used by server
host_key(Algorithm, Opts) ->
File = file_name(system, file_base_name(Algorithm), Opts),
%% We do not expect host keys to have pass phrases
%% so probably we could hardcod Password = ignore, but
%% we keep it as an undocumented option for now.
Password = proplists:get_value(identity_pass_phrase(Algorithm), Opts, ignore),
decode(File, Password).
is_auth_key(Key, User, Alg, Opts) ->
case lookup_user_key(Key, User, Alg, Opts) of
{ok, Key} ->
true;
_ ->
false
end.
%% Used by client
is_host_key(Key, PeerName, Algorithm, Opts) ->
case lookup_host_key(PeerName, Algorithm, Opts) of
{ok, Key} ->
true;
_ ->
false
end.
user_key(Algorithm, Opts) ->
File = file_name(user, identity_key_filename(Algorithm), Opts),
Password = proplists:get_value(identity_pass_phrase(Algorithm), Opts, ignore),
decode(File, Password).
%% Internal functions %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
file_base_name('ssh-rsa') ->
"ssh_host_rsa_key";
file_base_name('ssh-dss') ->
"ssh_host_dsa_key";
file_base_name(_) ->
"ssh_host_key".
decode(File, Password) ->
try
{ok, decode_ssh_file(read_ssh_file(File), Password)}
catch
throw:Reason ->
{error, Reason};
error:Reason ->
{error, Reason}
end.
read_ssh_file(File) ->
{ok, Bin} = file:read_file(File),
Bin.
%% Public key
decode_ssh_file(SshBin, public_key) ->
public_key:ssh_decode(SshBin, public_key);
%% Private Key
decode_ssh_file(Pem, Password) ->
case public_key:pem_decode(Pem) of
[{_, _, not_encrypted} = Entry] ->
public_key:pem_entry_decode(Entry);
[Entry] when Password =/= ignore ->
public_key:pem_entry_decode(Entry, Password);
_ ->
throw("No pass phrase provided for private key file")
end.
%% lookup_host_key
%% return {ok, Key(s)} or {error, not_found}
%%
lookup_host_key(Host, Alg, Opts) ->
Host1 = replace_localhost(Host),
do_lookup_host_key(Host1, Alg, Opts).
add_host_key(Host, Key, Opts) ->
Host1 = add_ip(replace_localhost(Host)),
KnownHosts = file_name(user, "known_hosts", Opts),
case file:open(KnownHosts, [write,append]) of
{ok, Fd} ->
ok = file:change_mode(KnownHosts, ?PERM_644),
Res = add_key_fd(Fd, Host1, Key),
file:close(Fd),
Res;
Error ->
Error
end.
lookup_user_key(Key, User, Alg, Opts) ->
SshDir = ssh_dir({remoteuser,User}, Opts),
case lookup_user_key_f(Key, User, SshDir, Alg, "authorized_keys", Opts) of
{ok, Key} ->
{ok, Key};
_ ->
lookup_user_key_f(Key, User, SshDir, Alg, "authorized_keys2", Opts)
end.
%%
%% Utils
%%
%% server use this to find individual keys for
%% an individual user when user tries to login
%% with publickey
ssh_dir({remoteuser, User}, Opts) ->
case proplists:get_value(user_dir_fun, Opts) of
undefined ->
case proplists:get_value(user_dir, Opts) of
undefined ->
default_user_dir();
Dir ->
Dir
end;
FUN ->
FUN(User)
end;
%% client use this to find client ssh keys
ssh_dir(user, Opts) ->
case proplists:get_value(user_dir, Opts, false) of
false -> default_user_dir();
D -> D
end;
%% server use this to find server host keys
ssh_dir(system, Opts) ->
proplists:get_value(system_dir, Opts, "/etc/ssh").
file_name(Type, Name, Opts) ->
FN = filename:join(ssh_dir(Type, Opts), Name),
FN.
%% in: "host" out: "host,1.2.3.4.
add_ip(Host) ->
case inet:getaddr(Host, inet) of
{ok, Addr} ->
case ssh_connection:encode_ip(Addr) of
false -> Host;
IPString -> Host ++ "," ++ IPString
end;
_ -> Host
end.
replace_localhost("localhost") ->
{ok, Hostname} = inet:gethostname(),
Hostname;
replace_localhost(Host) ->
Host.
do_lookup_host_key(Host, Alg, Opts) ->
case file:open(file_name(user, "known_hosts", Opts), [read, binary]) of
{ok, Fd} ->
Res = lookup_host_key_fd(Fd, Host, Alg),
file:close(Fd),
{ok, Res};
{error, enoent} -> {error, not_found};
Error -> Error
end.
identity_key_filename("ssh-dss") ->
"id_dsa";
identity_key_filename("ssh-rsa") ->
"id_rsa".
identity_pass_phrase("ssh-dss") ->
dsa_pass_phrase;
identity_pass_phrase('ssh-dss') ->
dsa_pass_phrase;
identity_pass_phrase('ssh-rsa') ->
rsa_pass_phrase;
identity_pass_phrase("ssh-rsa") ->
rsa_pass_phrase.
lookup_host_key_fd(Fd, Host, KeyType) ->
case io:get_line(Fd, '') of
eof ->
{error, not_found};
Line ->
case ssh_decode_line(Line, known_hosts) of
[{Key, Attributes}] ->
handle_host(Fd, Host, proplists:get_value(hostnames, Attributes), Key, KeyType);
[] ->
lookup_host_key_fd(Fd, Host, KeyType)
end
end.
ssh_decode_line(Line, Type) ->
try
public_key:ssh_decode(Line, Type)
catch _:_ ->
[]
end.
handle_host(Fd, Host, HostList, Key, KeyType) ->
Host1 = host_name(Host),
case lists:member(Host1, HostList) and key_match(Key, KeyType) of
true ->
Key;
false ->
lookup_host_key_fd(Fd, Host, KeyType)
end.
host_name(Atom) when is_atom(Atom) ->
atom_to_list(Atom);
host_name(List) ->
List.
key_match(#'RSAPublicKey'{}, "ssh-rsa") ->
true;
key_match({_, #'Dss-Parms'{}}, "ssh-dss") ->
true;
key_match(_, _) ->
false.
add_key_fd(Fd, Host,Key) ->
SshBin = public_key:ssh_encode([{Key, [{hostnames, [Host]}]}], known_hosts),
file:write(Fd, SshBin).
lookup_user_key_f(_, _User, [], _Alg, _F, _Opts) ->
{error, nouserdir};
lookup_user_key_f(_, _User, nouserdir, _Alg, _F, _Opts) ->
{error, nouserdir};
lookup_user_key_f(Key, _User, Dir, _Alg, F, _Opts) ->
FileName = filename:join(Dir, F),
case file:open(FileName, [read, binary]) of
{ok, Fd} ->
Res = lookup_user_key_fd(Fd, Key),
file:close(Fd),
Res;
{error, Reason} ->
{error, {{openerr, Reason}, {file, FileName}}}
end.
lookup_user_key_fd(Fd, Key) ->
case io:get_line(Fd, '') of
eof ->
{error, not_found};
Line ->
case ssh_decode_line(Line, auth_keys) of
[{AuthKey, _}] ->
case is_auth_key(Key, AuthKey) of
true ->
{ok, Key};
false ->
lookup_user_key_fd(Fd, Key)
end;
[] ->
lookup_user_key_fd(Fd, Key)
end
end.
is_auth_key(Key, Key) ->
true;
is_auth_key(_,_) ->
false.
default_user_dir()->
{ok,[[Home|_]]} = init:get_argument(home),
UserDir = filename:join(Home, ".ssh"),
ok = filelib:ensure_dir(filename:join(UserDir, "dummy")),
ok = file:change_mode(UserDir, ?PERM_700),
UserDir.
