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authorIngela Anderton Andin <[email protected]>2017-11-07 18:34:34 +0100
committerIngela Anderton Andin <[email protected]>2017-11-09 16:29:38 +0100
commit38b07caa2a1c6cd3537eadd36770afa54f067562 (patch)
tree6ede98ba4f15f9cfdd46ad3ea31ddca4d0a28cdf /lib/ssl/src/ssl_connection.erl
parent3e8c1ff94c0a73df71daadd4eb782c21c49f22d9 (diff)
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ssl: Countermeasurements for Bleichenbacher attack
Diffstat (limited to 'lib/ssl/src/ssl_connection.erl')
-rw-r--r--lib/ssl/src/ssl_connection.erl21
1 files changed, 19 insertions, 2 deletions
diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl
index b031d3d47b..b33ce63c32 100644
--- a/lib/ssl/src/ssl_connection.erl
+++ b/lib/ssl/src/ssl_connection.erl
@@ -1367,8 +1367,25 @@ server_certify_and_key_exchange(State0, Connection) ->
request_client_cert(State2, Connection).
certify_client_key_exchange(#encrypted_premaster_secret{premaster_secret= EncPMS},
- #state{private_key = Key} = State, Connection) ->
- PremasterSecret = ssl_handshake:premaster_secret(EncPMS, Key),
+ #state{private_key = Key, client_hello_version = {Major, Minor} = Version} = State, Connection) ->
+
+ %% Countermeasure for Bleichenbacher attack always provide some kind of premaster secret
+ %% and fail handshake later.RFC 5246 section 7.4.7.1.
+ PremasterSecret =
+ try ssl_handshake:premaster_secret(EncPMS, Key) of
+ Secret when erlang:byte_size(Secret) == ?NUM_OF_PREMASTERSECRET_BYTES ->
+ case Secret of
+ <<?BYTE(Major), ?BYTE(Minor), _/binary>> -> %% Correct
+ Secret;
+ <<?BYTE(_), ?BYTE(_), Rest/binary>> -> %% Version mismatch
+ <<?BYTE(Major), ?BYTE(Minor), Rest/binary>>
+ end;
+ _ -> %% erlang:byte_size(Secret) =/= ?NUM_OF_PREMASTERSECRET_BYTES
+ make_premaster_secret(Version, rsa)
+ catch
+ #alert{description = ?DECRYPT_ERROR} ->
+ make_premaster_secret(Version, rsa)
+ end,
calculate_master_secret(PremasterSecret, State, Connection, certify, cipher);
certify_client_key_exchange(#client_diffie_hellman_public{dh_public = ClientPublicDhKey},