From 89ae746305215c5dd077441ba796ff37b03fdaa3 Mon Sep 17 00:00:00 2001 From: Andreas Schultz Date: Fri, 24 Feb 2012 13:47:13 +0100 Subject: Some protocols (e.g. EAP-PEAP, EAP-TLS, EAP-TTLS) that use TLS as transport layer need to generate additional application specific key material. One way to generate such material is to use the TLS PRF and key material from the TLS session itself. This change makes it possible to use a TLS sessions PRF either with the session internal or caller supplied key material to generate additional key material. --- lib/ssl/doc/src/ssl.xml | 23 +++++++++++++++++++++++ lib/ssl/src/ssl.erl | 15 +++++++++++++-- lib/ssl/src/ssl_connection.erl | 39 ++++++++++++++++++++++++++++++++++++++- lib/ssl/src/ssl_handshake.erl | 14 +++++++++++++- lib/ssl/src/ssl_tls1.erl | 2 +- 5 files changed, 88 insertions(+), 5 deletions(-) diff --git a/lib/ssl/doc/src/ssl.xml b/lib/ssl/doc/src/ssl.xml index 50268ae206..d9f10a8c4c 100644 --- a/lib/ssl/doc/src/ssl.xml +++ b/lib/ssl/doc/src/ssl.xml @@ -122,6 +122,9 @@

hash() = md5 | sha

+

prf_random() = client_random | server_random +

+
@@ -560,6 +563,26 @@ fun(OtpCert :: #'OTPCertificate'{}, Event :: {bad_cert, Reason :: atom()} | + + prf(Socket, Secret, Label, Seed, WantedLength) -> {ok, binary()} | {error, reason()} + Use a sessions pseudo random function to generate key material. + + Socket = sslsocket() + Secret = binary() | master_secret + Label = binary() + Seed = [binary() | prf_random()] + WantedLength = non_neg_integer() + + +

Use the pseudo random function (PRF) of a TLS session to generate + additional key material. It either takes user generated values for + Secret and Seed or atoms directing it use a specific + value from the session security parameters.

+

This function can only be used with TLS connections, {error, undefined} + is returned for SSLv3 connections.

+ + + renegotiate(Socket) -> ok | {error, Reason} Initiates a new handshake. diff --git a/lib/ssl/src/ssl.erl b/lib/ssl/src/ssl.erl index d0693445e0..1048583eca 100644 --- a/lib/ssl/src/ssl.erl +++ b/lib/ssl/src/ssl.erl @@ -30,7 +30,7 @@ controlling_process/2, listen/2, pid/1, peername/1, peercert/1, recv/2, recv/3, send/2, getopts/2, setopts/2, sockname/1, versions/0, session_info/1, format_error/1, - renegotiate/1]). + renegotiate/1, prf/5]). -deprecated({pid, 1, next_major_release}). @@ -67,7 +67,7 @@ -type ssl_imp() :: new | old. -type transport_option() :: {cb_info, {CallbackModule::atom(), DataTag::atom(), ClosedTag::atom()}}. - +-type prf_random() :: client_random | server_random. %%-------------------------------------------------------------------- -spec start() -> ok | {error, reason()}. @@ -414,6 +414,17 @@ versions() -> renegotiate(#sslsocket{pid = Pid, fd = new_ssl}) -> ssl_connection:renegotiation(Pid). +%%-------------------------------------------------------------------- +-spec prf(#sslsocket{}, binary() | 'master_secret', binary(), + binary() | prf_random(), non_neg_integer()) -> + {ok, binary()} | {error, reason()}. +%% +%% Description: use a ssl sessions TLS PRF to generate key material +%%-------------------------------------------------------------------- +prf(#sslsocket{pid = Pid, fd = new_ssl}, + Secret, Label, Seed, WantedLength) -> + ssl_connection:prf(Pid, Secret, Label, Seed, WantedLength). + %%--------------------------------------------------------------- -spec format_error({error, term()}) -> list(). %% diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl index 28dd0c85d0..59133dccf0 100644 --- a/lib/ssl/src/ssl_connection.erl +++ b/lib/ssl/src/ssl_connection.erl @@ -40,7 +40,8 @@ -export([send/2, recv/3, connect/7, ssl_accept/6, handshake/2, socket_control/3, close/1, shutdown/2, new_user/2, get_opts/2, set_opts/2, info/1, session_info/1, - peer_certificate/1, sockname/1, peername/1, renegotiation/1]). + peer_certificate/1, sockname/1, peername/1, renegotiation/1, + prf/5]). %% Called by ssl_connection_sup -export([start_link/7]). @@ -273,6 +274,16 @@ peer_certificate(ConnectionPid) -> renegotiation(ConnectionPid) -> sync_send_all_state_event(ConnectionPid, renegotiate). +%%-------------------------------------------------------------------- +-spec prf(pid(), binary() | 'master_secret', binary(), + binary() | ssl:prf_secret(), non_neg_integer()) -> + {ok, binary()} | {error, reason()} | {'EXIT', term()}. +%% +%% Description: use a ssl sessions TLS PRF to generate key material +%%-------------------------------------------------------------------- +prf(ConnectionPid, Secret, Label, Seed, WantedLength) -> + sync_send_all_state_event(ConnectionPid, {prf, Secret, Label, Seed, WantedLength}). + %%==================================================================== %% ssl_connection_sup API %%==================================================================== @@ -868,6 +879,32 @@ handle_sync_event(renegotiate, From, connection, State) -> handle_sync_event(renegotiate, _, StateName, State) -> {reply, {error, already_renegotiating}, StateName, State, get_timeout(State)}; +handle_sync_event({prf, Secret, Label, Seed, WantedLength}, _, StateName, + #state{connection_states = ConnectionStates, + negotiated_version = Version} = State) -> + ConnectionState = + ssl_record:current_connection_state(ConnectionStates, read), + SecParams = ConnectionState#connection_state.security_parameters, + #security_parameters{master_secret = MasterSecret, + client_random = ClientRandom, + server_random = ServerRandom} = SecParams, + Reply = try + SecretToUse = case Secret of + _ when is_binary(Secret) -> Secret; + master_secret -> MasterSecret + end, + SeedToUse = lists:reverse( + lists:foldl(fun(X, Acc) when is_binary(X) -> [X|Acc]; + (client_random, Acc) -> [ClientRandom|Acc]; + (server_random, Acc) -> [ServerRandom|Acc] + end, [], Seed)), + ssl_handshake:prf(Version, SecretToUse, Label, SeedToUse, WantedLength) + catch + exit:_ -> {error, badarg}; + error:Reason -> {error, Reason} + end, + {reply, Reply, StateName, State, get_timeout(State)}; + handle_sync_event(info, _, StateName, #state{negotiated_version = Version, session = #session{cipher_suite = Suite}} = State) -> diff --git a/lib/ssl/src/ssl_handshake.erl b/lib/ssl/src/ssl_handshake.erl index 542033e6ce..ef60cac6df 100644 --- a/lib/ssl/src/ssl_handshake.erl +++ b/lib/ssl/src/ssl_handshake.erl @@ -37,7 +37,7 @@ finished/4, verify_connection/5, get_tls_handshake/2, decode_client_key/3, server_hello_done/0, encode_handshake/2, init_hashes/0, update_hashes/2, - decrypt_premaster_secret/2]). + decrypt_premaster_secret/2, prf/5]). -export([dec_hello_extensions/2]). @@ -542,6 +542,18 @@ server_key_exchange_hash(Algorithm, Value) when Algorithm == rsa; server_key_exchange_hash(dhe_dss, Value) -> crypto:sha(Value). +%%-------------------------------------------------------------------- +-spec prf(tls_version(), binary(), binary(), binary(), non_neg_integer()) -> + {ok, binary()} | {error, undefined}. +%% +%% Description: use the TLS PRF to generate key material +%%-------------------------------------------------------------------- +prf({3,0}, _, _, _, _) -> + {error, undefined}; +prf({3,N}, Secret, Label, Seed, WantedLength) + when N == 1; N == 2 -> + {ok, ssl_tls1:prf(Secret, Label, Seed, WantedLength)}. + %%-------------------------------------------------------------------- %%% Internal functions %%-------------------------------------------------------------------- diff --git a/lib/ssl/src/ssl_tls1.erl b/lib/ssl/src/ssl_tls1.erl index 5f9850c386..7351f34b61 100644 --- a/lib/ssl/src/ssl_tls1.erl +++ b/lib/ssl/src/ssl_tls1.erl @@ -29,7 +29,7 @@ -include("ssl_record.hrl"). -export([master_secret/3, finished/3, certificate_verify/2, mac_hash/7, - setup_keys/6, suites/0]). + setup_keys/6, suites/0, prf/4]). %%==================================================================== %% Internal application API -- cgit v1.2.3