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authorAndreas Schultz <[email protected]>2013-06-11 19:59:54 +0200
committerIngela Anderton Andin <[email protected]>2013-09-10 09:37:29 +0200
commit2be6aa6c6a3f44d86fe401e0d467c66c3d4114aa (patch)
tree8b2e842ba902ad071c886d838589beb987bbe1b1 /lib/ssl
parent122edd2be9d6b1144fa04f6b7be8d75265473a50 (diff)
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ssl: Add DTLS handshake primitivs.
This code is to 99 % written by Andreas Schultz only some small changes to start integrating with OTPs DTLS solution.
Diffstat (limited to 'lib/ssl')
-rw-r--r--lib/ssl/src/dtls_handshake.erl406
1 files changed, 406 insertions, 0 deletions
diff --git a/lib/ssl/src/dtls_handshake.erl b/lib/ssl/src/dtls_handshake.erl
index b25daa59d9..492212cbae 100644
--- a/lib/ssl/src/dtls_handshake.erl
+++ b/lib/ssl/src/dtls_handshake.erl
@@ -16,3 +16,409 @@
%%
%% %CopyrightEnd%
-module(dtls_handshake).
+
+-include("dtls_handshake.hrl").
+-include("dtls_record.hrl").
+-include("ssl_internal.hrl").
+
+-export([get_dtls_handshake/2,
+ dtls_handshake_new_flight/1, dtls_handshake_new_epoch/1,
+ encode_handshake/4]).
+
+-record(dtls_hs_state, {current_read_seq, starting_read_seq, highest_record_seq, fragments, completed}).
+
+-type dtls_handshake() :: #client_hello{} | #server_hello{} | #hello_verify_request{} |
+ #server_hello_done{} | #certificate{} | #certificate_request{} |
+ #client_key_exchange{} | #finished{} | #certificate_verify{} |
+ #hello_request{} | #next_protocol{}.
+
+%%====================================================================
+%% Internal application API
+%%====================================================================
+encode_handshake(Package, Version, MsgSeq, Mss) ->
+ {MsgType, Bin} = enc_hs(Package, Version),
+ Len = byte_size(Bin),
+ HsHistory = [MsgType, ?uint24(Len), ?uint16(MsgSeq), ?uint24(0), ?uint24(Len), Bin],
+ BinMsg = dtls_split_handshake(Mss, MsgType, Len, MsgSeq, Bin, 0, []),
+ {HsHistory, BinMsg}.
+
+%--------------------------------------------------------------------
+-spec get_dtls_handshake(#ssl_tls{}, #dtls_hs_state{} | binary()) ->
+ {[dtls_handshake()], #ssl_tls{}}.
+%
+% Description: Given a DTLS state and new data from ssl_record, collects
+% and returns it as a list of handshake messages, also returns a new
+% DTLS state
+%--------------------------------------------------------------------
+% get_dtls_handshake(Record, <<>>) ->
+% get_dtls_handshake_aux(Record, dtls_hs_state_init());
+get_dtls_handshake(Record, HsState) ->
+ get_dtls_handshake_aux(Record, HsState).
+
+%--------------------------------------------------------------------
+-spec dtls_handshake_new_epoch(#dtls_hs_state{}) -> #dtls_hs_state{}.
+%
+% Description: Reset the DTLS decoder state for a new Epoch
+%--------------------------------------------------------------------
+% dtls_handshake_new_epoch(<<>>) ->
+% dtls_hs_state_init();
+dtls_handshake_new_epoch(HsState) ->
+ HsState#dtls_hs_state{highest_record_seq = 0,
+ starting_read_seq = HsState#dtls_hs_state.current_read_seq,
+ fragments = gb_trees:empty(), completed = []}.
+
+%--------------------------------------------------------------------
+-spec dtls_handshake_new_flight(integer() | undefined) -> #dtls_hs_state{}.
+%
+% Description: Init the DTLS decoder state for a new Flight
+dtls_handshake_new_flight(ExpectedReadReq) ->
+ #dtls_hs_state{current_read_seq = ExpectedReadReq,
+ highest_record_seq = 0,
+ starting_read_seq = 0,
+ fragments = gb_trees:empty(), completed = []}.
+
+%%--------------------------------------------------------------------
+%%% Internal functions
+%%--------------------------------------------------------------------
+
+dtls_split_handshake(Mss, MsgType, Len, MsgSeq, Bin, Offset, Acc)
+ when byte_size(Bin) + 12 < Mss ->
+ FragmentLen = byte_size(Bin),
+ BinMsg = [MsgType, ?uint24(Len), ?uint16(MsgSeq), ?uint24(Offset), ?uint24(FragmentLen), Bin],
+ lists:reverse([BinMsg|Acc]);
+dtls_split_handshake(Mss, MsgType, Len, MsgSeq, Bin, Offset, Acc) ->
+ FragmentLen = Mss - 12,
+ <<Fragment:FragmentLen/bytes, Rest/binary>> = Bin,
+ BinMsg = [MsgType, ?uint24(Len), ?uint16(MsgSeq), ?uint24(Offset), ?uint24(FragmentLen), Fragment],
+ dtls_split_handshake(Mss, MsgType, Len, MsgSeq, Rest, Offset + FragmentLen, [BinMsg|Acc]).
+
+get_dtls_handshake_aux(#ssl_tls{version = Version,
+ record_seq = SeqNo,
+ fragment = Data}, HsState) ->
+ get_dtls_handshake_aux(Version, SeqNo, Data, HsState).
+
+get_dtls_handshake_aux(Version, SeqNo,
+ <<?BYTE(Type), ?UINT24(Length),
+ ?UINT16(MessageSeq),
+ ?UINT24(FragmentOffset), ?UINT24(FragmentLength),
+ Body:FragmentLength/binary, Rest/binary>>,
+ HsState0) ->
+ case reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq,
+ FragmentOffset, FragmentLength,
+ Body, HsState0) of
+ {retransmit, HsState1} ->
+ case Rest of
+ <<>> ->
+ {retransmit, HsState1};
+ _ ->
+ get_dtls_handshake_aux(Version, SeqNo, Rest, HsState1)
+ end;
+ {HsState1, HighestSeqNo, MsgBody} ->
+ HsState2 = dec_dtls_fragment(Version, HighestSeqNo, Type, Length, MessageSeq, MsgBody, HsState1),
+ HsState3 = process_dtls_fragments(Version, HsState2),
+ get_dtls_handshake_aux(Version, SeqNo, Rest, HsState3);
+ HsState2 ->
+ HsState3 = process_dtls_fragments(Version, HsState2),
+ get_dtls_handshake_aux(Version, SeqNo, Rest, HsState3)
+ end;
+
+get_dtls_handshake_aux(_Version, _SeqNo, <<>>, HsState) ->
+ {lists:reverse(HsState#dtls_hs_state.completed),
+ HsState#dtls_hs_state.highest_record_seq,
+ HsState#dtls_hs_state{completed = []}}.
+
+dec_dtls_fragment(Version, SeqNo, Type, Length, MessageSeq, MsgBody,
+ HsState = #dtls_hs_state{highest_record_seq = HighestSeqNo, completed = Acc}) ->
+ Raw = <<?BYTE(Type), ?UINT24(Length), ?UINT16(MessageSeq), ?UINT24(0), ?UINT24(Length), MsgBody/binary>>,
+ H = dec_hs(Version, Type, MsgBody),
+ HsState#dtls_hs_state{completed = [{H,Raw}|Acc], highest_record_seq = erlang:max(HighestSeqNo, SeqNo)}.
+
+process_dtls_fragments(Version,
+ HsState0 = #dtls_hs_state{current_read_seq = CurrentReadSeq,
+ fragments = Fragments0}) ->
+ case gb_trees:is_empty(Fragments0) of
+ true ->
+ HsState0;
+ _ ->
+ case gb_trees:smallest(Fragments0) of
+ {CurrentReadSeq, {SeqNo, Type, Length, CurrentReadSeq, {Length, [{0, Length}], MsgBody}}} ->
+ HsState1 = dtls_hs_state_process_seq(HsState0),
+ HsState2 = dec_dtls_fragment(Version, SeqNo, Type, Length, CurrentReadSeq, MsgBody, HsState1),
+ process_dtls_fragments(Version, HsState2);
+ _ ->
+ HsState0
+ end
+ end.
+
+dtls_hs_state_process_seq(HsState0 = #dtls_hs_state{current_read_seq = CurrentReadSeq,
+ fragments = Fragments0}) ->
+ Fragments1 = gb_trees:delete_any(CurrentReadSeq, Fragments0),
+ HsState0#dtls_hs_state{current_read_seq = CurrentReadSeq + 1,
+ fragments = Fragments1}.
+
+dtls_hs_state_add_fragment(MessageSeq, Fragment, HsState0 = #dtls_hs_state{fragments = Fragments0}) ->
+ Fragments1 = gb_trees:enter(MessageSeq, Fragment, Fragments0),
+ HsState0#dtls_hs_state{fragments = Fragments1}.
+
+reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq, 0, Length,
+ Body, HsState0 = #dtls_hs_state{current_read_seq = undefined})
+ when Type == ?CLIENT_HELLO;
+ Type == ?SERVER_HELLO;
+ Type == ?HELLO_VERIFY_REQUEST ->
+ %% First message, should be client hello
+ %% return the current message and set the next expected Sequence
+ %%
+ %% Note: this could (should?) be restricted further, ClientHello and
+ %% HelloVerifyRequest have to have message_seq = 0, ServerHello
+ %% can have a message_seq of 0 or 1
+ %%
+ {HsState0#dtls_hs_state{current_read_seq = MessageSeq + 1}, SeqNo, Body};
+
+reassemble_dtls_fragment(_SeqNo, _Type, Length, _MessageSeq, _, Length,
+ _Body, HsState = #dtls_hs_state{current_read_seq = undefined}) ->
+ %% not what we expected, drop it
+ HsState;
+
+reassemble_dtls_fragment(SeqNo, _Type, Length, MessageSeq, 0, Length,
+ Body, HsState0 =
+ #dtls_hs_state{starting_read_seq = StartingReadSeq})
+ when MessageSeq < StartingReadSeq ->
+ %% this has to be the start of a new flight, let it through
+ %%
+ %% Note: this could (should?) be restricted further, the first message of a
+ %% new flight has to have message_seq = 0
+ %%
+ HsState = dtls_hs_state_process_seq(HsState0),
+ {HsState, SeqNo, Body};
+
+reassemble_dtls_fragment(_SeqNo, _Type, Length, MessageSeq, 0, Length,
+ _Body, HsState =
+ #dtls_hs_state{current_read_seq = CurrentReadSeq})
+ when MessageSeq < CurrentReadSeq ->
+ {retransmit, HsState};
+
+reassemble_dtls_fragment(_SeqNo, _Type, Length, MessageSeq, 0, Length,
+ _Body, HsState = #dtls_hs_state{current_read_seq = CurrentReadSeq})
+ when MessageSeq < CurrentReadSeq ->
+ HsState;
+
+reassemble_dtls_fragment(SeqNo, _Type, Length, MessageSeq, 0, Length,
+ Body, HsState0 = #dtls_hs_state{current_read_seq = MessageSeq}) ->
+ %% Message fully contained and it's the current seq
+ HsState1 = dtls_hs_state_process_seq(HsState0),
+ {HsState1, SeqNo, Body};
+
+reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq, 0, Length,
+ Body, HsState) ->
+ %% Message fully contained and it's the NOT the current seq -> buffer
+ Fragment = {SeqNo, Type, Length, MessageSeq,
+ dtls_fragment_init(Length, 0, Length, Body)},
+ dtls_hs_state_add_fragment(MessageSeq, Fragment, HsState);
+
+reassemble_dtls_fragment(_SeqNo, _Type, Length, MessageSeq, FragmentOffset, FragmentLength,
+ _Body,
+ HsState = #dtls_hs_state{current_read_seq = CurrentReadSeq})
+ when FragmentOffset + FragmentLength == Length andalso MessageSeq == (CurrentReadSeq - 1) ->
+ {retransmit, HsState};
+
+reassemble_dtls_fragment(_SeqNo, _Type, _Length, MessageSeq, _FragmentOffset, _FragmentLength,
+ _Body,
+ HsState = #dtls_hs_state{current_read_seq = CurrentReadSeq})
+ when MessageSeq < CurrentReadSeq ->
+ HsState;
+
+reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq,
+ FragmentOffset, FragmentLength,
+ Body,
+ HsState = #dtls_hs_state{fragments = Fragments0}) ->
+ case gb_trees:lookup(MessageSeq, Fragments0) of
+ {value, Fragment} ->
+ dtls_fragment_reassemble(SeqNo, Type, Length, MessageSeq,
+ FragmentOffset, FragmentLength,
+ Body, Fragment, HsState);
+ none ->
+ dtls_fragment_start(SeqNo, Type, Length, MessageSeq,
+ FragmentOffset, FragmentLength,
+ Body, HsState)
+ end.
+
+dtls_fragment_start(SeqNo, Type, Length, MessageSeq,
+ FragmentOffset, FragmentLength,
+ Body, HsState = #dtls_hs_state{fragments = Fragments0}) ->
+ Fragment = {SeqNo, Type, Length, MessageSeq,
+ dtls_fragment_init(Length, FragmentOffset, FragmentLength, Body)},
+ Fragments1 = gb_trees:insert(MessageSeq, Fragment, Fragments0),
+ HsState#dtls_hs_state{fragments = Fragments1}.
+
+dtls_fragment_reassemble(SeqNo, Type, Length, MessageSeq,
+ FragmentOffset, FragmentLength,
+ Body,
+ {LastSeqNo, Type, Length, MessageSeq, FragBuffer0},
+ HsState = #dtls_hs_state{fragments = Fragments0}) ->
+ FragBuffer1 = dtls_fragment_add(FragBuffer0, FragmentOffset, FragmentLength, Body),
+ Fragment = {erlang:max(SeqNo, LastSeqNo), Type, Length, MessageSeq, FragBuffer1},
+ Fragments1 = gb_trees:enter(MessageSeq, Fragment, Fragments0),
+ HsState#dtls_hs_state{fragments = Fragments1};
+
+%% Type, Length or Seq mismatch, drop everything...
+%% Note: the RFC is not clear on how to handle this...
+dtls_fragment_reassemble(_SeqNo, _Type, _Length, MessageSeq,
+ _FragmentOffset, _FragmentLength, _Body, _Fragment,
+ HsState = #dtls_hs_state{fragments = Fragments0}) ->
+ Fragments1 = gb_trees:delete_any(MessageSeq, Fragments0),
+ HsState#dtls_hs_state{fragments = Fragments1}.
+
+dtls_fragment_add({Length, FragmentList0, Bin0}, FragmentOffset, FragmentLength, Body) ->
+ Bin1 = dtls_fragment_bin_add(FragmentOffset, FragmentLength, Body, Bin0),
+ FragmentList1 = add_fragment(FragmentList0, {FragmentOffset, FragmentLength}),
+ {Length, FragmentList1, Bin1}.
+
+dtls_fragment_init(Length, 0, Length, Body) ->
+ {Length, [{0, Length}], Body};
+dtls_fragment_init(Length, FragmentOffset, FragmentLength, Body) ->
+ Bin = dtls_fragment_bin_add(FragmentOffset, FragmentLength, Body, <<0:(Length*8)>>),
+ {Length, [{FragmentOffset, FragmentLength}], Bin}.
+
+dtls_fragment_bin_add(FragmentOffset, FragmentLength, Add, Buffer) ->
+ <<First:FragmentOffset/bytes, _:FragmentLength/bytes, Rest/binary>> = Buffer,
+ <<First/binary, Add/binary, Rest/binary>>.
+
+merge_fragment_list([], Fragment, Acc) ->
+ lists:reverse([Fragment|Acc]);
+
+merge_fragment_list([H = {_, HEnd}|Rest], Frag = {FStart, _}, Acc)
+ when FStart > HEnd ->
+ merge_fragment_list(Rest, Frag, [H|Acc]);
+
+merge_fragment_list(Rest = [{HStart, _HEnd}|_], Frag = {_FStart, FEnd}, Acc)
+ when FEnd < HStart ->
+ lists:reverse(Acc) ++ [Frag|Rest];
+
+merge_fragment_list([{HStart, HEnd}|Rest], _Frag = {FStart, FEnd}, Acc)
+ when
+ FStart =< HEnd orelse FEnd >= HStart ->
+ Start = erlang:min(HStart, FStart),
+ End = erlang:max(HEnd, FEnd),
+ NewFrag = {Start, End},
+ merge_fragment_list(Rest, NewFrag, Acc).
+
+add_fragment(List, {FragmentOffset, FragmentLength}) ->
+ merge_fragment_list(List, {FragmentOffset, FragmentOffset + FragmentLength}, []).
+
+
+dec_hs(_Version, ?HELLO_VERIFY_REQUEST, <<?BYTE(Major), ?BYTE(Minor),
+ ?BYTE(CookieLength), Cookie:CookieLength/binary>>)
+ when Major >= 128 ->
+
+ #hello_verify_request{
+ protocol_version = {Major, Minor},
+ cookie = Cookie};
+
+dec_hs(_Version, ?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+ ?BYTE(SID_length), Session_ID:SID_length/binary,
+ ?BYTE(Cookie_length), Cookie:Cookie_length/binary,
+ ?UINT16(Cs_length), CipherSuites:Cs_length/binary,
+ ?BYTE(Cm_length), Comp_methods:Cm_length/binary,
+ Extensions/binary>>)
+ when Major >= 128 ->
+
+ DecodedExtensions = tls_handshake:dec_hello_extensions(Extensions),
+ RenegotiationInfo = proplists:get_value(renegotiation_info, DecodedExtensions, undefined),
+ SRP = proplists:get_value(srp, DecodedExtensions, undefined),
+ HashSigns = proplists:get_value(hash_signs, DecodedExtensions, undefined),
+ EllipticCurves = proplists:get_value(elliptic_curves, DecodedExtensions,
+ undefined),
+ NextProtocolNegotiation = proplists:get_value(next_protocol_negotiation, DecodedExtensions, undefined),
+
+ #client_hello{
+ client_version = {Major,Minor},
+ random = Random,
+ session_id = Session_ID,
+ cookie = Cookie,
+ cipher_suites = tls_handshake:decode_suites('2_bytes', CipherSuites),
+ compression_methods = Comp_methods,
+ renegotiation_info = RenegotiationInfo,
+ srp = SRP,
+ hash_signs = HashSigns,
+ elliptic_curves = EllipticCurves,
+ next_protocol_negotiation = NextProtocolNegotiation
+ }.
+
+enc_hs(#hello_verify_request{protocol_version = {Major, Minor},
+ cookie = Cookie}, _Version) ->
+ CookieLength = byte_size(Cookie),
+ {?HELLO_VERIFY_REQUEST, <<?BYTE(Major), ?BYTE(Minor),
+ ?BYTE(CookieLength),
+ Cookie/binary>>};
+
+enc_hs(#client_hello{client_version = {Major, Minor},
+ random = Random,
+ session_id = SessionID,
+ cookie = Cookie,
+ cipher_suites = CipherSuites,
+ compression_methods = CompMethods,
+ renegotiation_info = RenegotiationInfo,
+ srp = SRP,
+ hash_signs = HashSigns,
+ ec_point_formats = EcPointFormats,
+ elliptic_curves = EllipticCurves,
+ next_protocol_negotiation = NextProtocolNegotiation}, Version) ->
+ SIDLength = byte_size(SessionID),
+ BinCookie = enc_client_hello_cookie(Version, Cookie),
+ BinCompMethods = list_to_binary(CompMethods),
+ CmLength = byte_size(BinCompMethods),
+ BinCipherSuites = list_to_binary(CipherSuites),
+ CsLength = byte_size(BinCipherSuites),
+ Extensions = tls_handshake:hello_extensions(RenegotiationInfo, SRP, NextProtocolNegotiation)
+ ++ tls_handshake:ec_hello_extensions(lists:map(fun ssl_cipher:suite_definition/1, CipherSuites), EcPointFormats)
+ ++ tls_handshake:ec_hello_extensions(lists:map(fun ssl_cipher:suite_definition/1, CipherSuites), EllipticCurves)
+ ++ tls_handshake:hello_extensions(HashSigns),
+ ExtensionsBin = tls_handshake:enc_hello_extensions(Extensions),
+
+ {?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+ ?BYTE(SIDLength), SessionID/binary,
+ BinCookie/binary,
+ ?UINT16(CsLength), BinCipherSuites/binary,
+ ?BYTE(CmLength), BinCompMethods/binary, ExtensionsBin/binary>>}.
+
+enc_client_hello_cookie(_, Cookie) ->
+ CookieLength = byte_size(Cookie),
+ <<?BYTE(CookieLength), Cookie/binary>>;
+enc_client_hello_cookie(_, _) ->
+ <<>>.
+
+dec_hs(_Version, ?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+ ?BYTE(SID_length), Session_ID:SID_length/binary,
+ ?BYTE(Cookie_length), Cookie:Cookie_length/binary,
+ ?UINT16(Cs_length), CipherSuites:Cs_length/binary,
+ ?BYTE(Cm_length), Comp_methods:Cm_length/binary,
+ Extensions/binary>>) ->
+
+ DecodedExtensions = dec_hello_extensions(Extensions),
+ RenegotiationInfo = proplists:get_value(renegotiation_info, DecodedExtensions, undefined),
+ SRP = proplists:get_value(srp, DecodedExtensions, undefined),
+ HashSigns = proplists:get_value(hash_signs, DecodedExtensions, undefined),
+ EllipticCurves = proplists:get_value(elliptic_curves, DecodedExtensions,
+ undefined),
+ NextProtocolNegotiation = proplists:get_value(next_protocol_negotiation, DecodedExtensions, undefined),
+
+ #client_hello{
+ client_version = {Major,Minor},
+ random = Random,
+ session_id = Session_ID,
+ cookie = Cookie,
+ cipher_suites = from_2bytes(CipherSuites),
+ compression_methods = Comp_methods,
+ renegotiation_info = RenegotiationInfo,
+ srp = SRP,
+ hash_signs = HashSigns,
+ elliptic_curves = EllipticCurves,
+ next_protocol_negotiation = NextProtocolNegotiation
+ };
+
+dec_hs(_Version, ?HELLO_VERIFY_REQUEST, <<?BYTE(Major), ?BYTE(Minor),
+ ?BYTE(CookieLength), Cookie:CookieLength/binary>>) ->
+
+ #hello_verify_request{
+ server_version = {Major,Minor},
+ cookie = Cookie};