diff options
Diffstat (limited to 'lib/ssh/src/ssh_transport.erl')
-rw-r--r-- | lib/ssh/src/ssh_transport.erl | 176 |
1 files changed, 59 insertions, 117 deletions
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl index d622ec27fc..0c999b96cc 100644 --- a/lib/ssh/src/ssh_transport.erl +++ b/lib/ssh/src/ssh_transport.erl @@ -441,19 +441,29 @@ handle_kexdh_reply(#ssh_msg_kexdh_reply{public_host_key = PeerPubHostKey, %%% %%% diffie-hellman-group-exchange-sha1 %%% -handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = Min, +handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = Min0, n = NBits, - max = Max}, - Ssh0=#ssh{opts=Opts}) when Min=<NBits, NBits=<Max -> + max = Max0}, + Ssh0=#ssh{opts=Opts}) when Min0=<NBits, NBits=<Max0 -> %% server - {G, P} = dh_gex_group(Min, NBits, Max, proplists:get_value(dh_gex_groups,Opts)), - {Public, Private} = generate_key(dh, [P,G]), - {SshPacket, Ssh} = - ssh_packet(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0), - {ok, SshPacket, - Ssh#ssh{keyex_key = {{Private, Public}, {G, P}}, - keyex_info = {Min, Max, NBits} - }}; + {Min, Max} = adjust_gex_min_max(Min0, Max0, Opts), + case public_key:dh_gex_group(Min, NBits, Max, + proplists:get_value(dh_gex_groups,Opts)) of + {ok, {_Sz, {G,P}}} -> + {Public, Private} = generate_key(dh, [P,G]), + {SshPacket, Ssh} = + ssh_packet(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0), + {ok, SshPacket, + Ssh#ssh{keyex_key = {{Private, Public}, {G, P}}, + keyex_info = {Min, Max, NBits} + }}; + {error,_} -> + throw(#ssh_msg_disconnect{ + code = ?SSH_DISCONNECT_PROTOCOL_ERROR, + description = "No possible diffie-hellman-group-exchange group found", + language = ""}) + end; + handle_kex_dh_gex_request(_, _) -> throw({{error,bad_ssh_msg_kex_dh_gex_request}, #ssh_msg_disconnect{ @@ -462,6 +472,26 @@ handle_kex_dh_gex_request(_, _) -> language = ""} }). + +adjust_gex_min_max(Min0, Max0, Opts) -> + case proplists:get_value(dh_gex_limits, Opts) of + undefined -> + {Min0, Max0}; + {Min1, Max1} -> + Min2 = max(Min0, Min1), + Max2 = min(Max0, Max1), + if + Min2 =< Max2 -> + {Min2, Max2}; + Max2 < Min2 -> + throw(#ssh_msg_disconnect{ + code = ?SSH_DISCONNECT_PROTOCOL_ERROR, + description = "No possible diffie-hellman-group-exchange group possible", + language = ""}) + end + end. + + handle_kex_dh_gex_group(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0) -> %% client {Public, Private} = generate_key(dh, [P,G]), @@ -563,10 +593,11 @@ handle_kex_ecdh_init(#ssh_msg_kex_ecdh_init{q_c = PeerPublic}, Ssh0 = #ssh{algorithms = #alg{kex=Kex}}) -> %% at server Curve = ecdh_curve(Kex), - case ecdh_validate_public_key(PeerPublic, Curve) of - true -> - {MyPublic, MyPrivate} = generate_key(ecdh, Curve), - K = compute_key(ecdh, PeerPublic, MyPrivate, Curve), + {MyPublic, MyPrivate} = generate_key(ecdh, Curve), + try + compute_key(ecdh, PeerPublic, MyPrivate, Curve) + of + K -> MyPrivHostKey = get_host_key(Ssh0), MyPubHostKey = extract_public_key(MyPrivHostKey), H = kex_h(Ssh0, Curve, MyPubHostKey, PeerPublic, MyPublic, K), @@ -579,9 +610,9 @@ handle_kex_ecdh_init(#ssh_msg_kex_ecdh_init{q_c = PeerPublic}, {ok, SshPacket, Ssh1#ssh{keyex_key = {{MyPublic,MyPrivate},Curve}, shared_secret = K, exchanged_hash = H, - session_id = sid(Ssh1, H)}}; - - false -> + session_id = sid(Ssh1, H)}} + catch + _:_ -> throw({{error,invalid_peer_public_key}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, @@ -596,9 +627,10 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey, #ssh{keyex_key = {{MyPublic,MyPrivate}, Curve}} = Ssh0 ) -> %% at client - case ecdh_validate_public_key(PeerPublic, Curve) of - true -> - K = compute_key(ecdh, PeerPublic, MyPrivate, Curve), + try + compute_key(ecdh, PeerPublic, MyPrivate, Curve) + of + K -> H = kex_h(Ssh0, Curve, PeerPubHostKey, MyPublic, PeerPublic, K), case verify_host_key(Ssh0, PeerPubHostKey, H, H_SIG) of ok -> @@ -613,9 +645,9 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey, description = "Key exchange failed", language = ""} }) - end; - - false -> + end + catch + _:_ -> throw({{error,invalid_peer_public_key}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, @@ -626,62 +658,6 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey, %%%---------------------------------------------------------------- -%%% -%%% Standards for Efficient Cryptography Group, "Elliptic Curve Cryptography", SEC 1 -%%% Section 3.2.2.1 -%%% - -ecdh_validate_public_key(Key, Curve) -> - case key_size(Curve) of - undefined -> - false; - - Sz -> - case dec_key(Key, Sz) of - {ok,Q} -> - case crypto:ec_curve(Curve) of - {{prime_field,P}, {A, B, _Seed}, - _P0Bin, _OrderBin, _CoFactorBin} -> - on_curve(Q, bin2int(A), bin2int(B), bin2int(P)) - end; - - {error,compressed_not_implemented} -> % Be a bit generous... - true; - - _Error -> - false - end - end. - - -on_curve({X,Y}, A, B, P) when 0 =< X,X =< (P-1), - 0 =< Y,Y =< (P-1) -> - %% Section 3.2.2.1, point 2 - (Y*Y) rem P == (X*X*X + A*X + B) rem P; -on_curve(_, _, _, _) -> - false. - - -bin2int(B) -> - Sz = erlang:bit_size(B), - <<I:Sz/big-unsigned-integer>> = B, - I. - -key_size(secp256r1) -> 256; -key_size(secp384r1) -> 384; -key_size(secp521r1) -> 528; % Round 521 up to closest 8-bits. -key_size(_) -> undefined. - - -dec_key(Key, NBits) -> - Size = 8 + 2*NBits, - case <<Key:Size>> of - <<4:8, X:NBits, Y:NBits>> -> {ok,{X,Y}}; - <<4:8, _/binary>> -> {error,bad_format}; - _ -> {error,compressed_not_implemented} - end. - -%%%---------------------------------------------------------------- handle_new_keys(#ssh_msg_newkeys{}, Ssh0) -> try install_alg(Ssh0) of #ssh{} = Ssh -> @@ -1482,44 +1458,10 @@ peer_name({Host, _}) -> %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -dh_group('diffie-hellman-group1-sha1') -> element(2, ?dh_group1); -dh_group('diffie-hellman-group14-sha1') -> element(2, ?dh_group14). - -dh_gex_default_groups() -> ?dh_default_groups. - - -dh_gex_group(Min, N, Max, undefined) -> - dh_gex_group(Min, N, Max, dh_gex_default_groups()); -dh_gex_group(Min, N, Max, Groups) -> - %% First try to find an exact match. If not an exact match, select the largest possible. - {_Size,Group} = - lists:foldl( - fun(_, {I,G}) when I==N -> - %% If we have an exact match already: use that one - {I,G}; - ({I,G}, _) when I==N -> - %% If we now found an exact match: use that very one - {I,G}; - ({I,G}, {Imax,_Gmax}) when Min=<I,I=<Max, % a) {I,G} fullfills the requirements - I>Imax -> % b) {I,G} is larger than current max - %% A group within the limits and better than the one we have - {I,G}; - (_, IGmax) -> - %% Keep the one we have - IGmax - end, {-1,undefined}, Groups), - - case Group of - undefined -> - throw(#ssh_msg_disconnect{ - code = ?SSH_DISCONNECT_PROTOCOL_ERROR, - description = "No possible diffie-hellman-group-exchange group found", - language = ""}); - _ -> - Group - end. - +dh_group('diffie-hellman-group1-sha1') -> ?dh_group1; +dh_group('diffie-hellman-group14-sha1') -> ?dh_group14. +%%%---------------------------------------------------------------- generate_key(Algorithm, Args) -> {Public,Private} = crypto:generate_key(Algorithm, Args), {crypto:bytes_to_integer(Public), crypto:bytes_to_integer(Private)}. |