From be66663142da66e013ad65c4ebe429d9391312b0 Mon Sep 17 00:00:00 2001
From: Andreas Schultz <aschultz@tpip.net>
Date: Thu, 16 Aug 2012 11:23:33 +0200
Subject: ssl: TLS 1.2: fix hash and signature handling

with TLS 1.2 the hash and signature on a certify message can
differ from the defaults. So we have to make sure to always
use the hash and signature algorithm indicated in the
handshake message
---
 lib/ssl/src/ssl_connection.erl | 9 +++++++--
 lib/ssl/src/ssl_handshake.erl  | 2 +-
 lib/ssl/src/ssl_tls1.erl       | 6 +++---
 3 files changed, 11 insertions(+), 6 deletions(-)

(limited to 'lib/ssl')

diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl
index c09e07018d..fc2488952d 100644
--- a/lib/ssl/src/ssl_connection.erl
+++ b/lib/ssl/src/ssl_connection.erl
@@ -640,14 +640,18 @@ cipher(#hello_request{}, State0) ->
     {Record, State} = next_record(State0),
     next_state(cipher, hello, Record, State);
 
-cipher(#certificate_verify{signature = Signature}, 
+cipher(#certificate_verify{signature = Signature, hashsign_algorithm = CertHashSign},
        #state{role = server, 
 	      public_key_info = PublicKeyInfo,
 	      negotiated_version = Version,
 	      session = #session{master_secret = MasterSecret},
-	      hashsign_algorithm = HashSign,
+	      hashsign_algorithm = ConnectionHashSign,
 	      tls_handshake_history = Handshake
 	     } = State0) -> 
+    HashSign = case CertHashSign of
+		   {_, _} -> CertHashSign;
+		   _      -> ConnectionHashSign
+	       end,
     case ssl_handshake:certificate_verify(Signature, PublicKeyInfo,
 					  Version, HashSign, MasterSecret, Handshake) of
 	valid ->
@@ -1253,6 +1257,7 @@ verify_client_cert(#state{client_certificate_requested = true, role = client,
 			  hashsign_algorithm = HashSign,
 			  tls_handshake_history = Handshake0} = State) ->
 
+    %%TODO: for TLS 1.2 we can choose a different/stronger HashSign combination for this.
     case ssl_handshake:client_certificate_verify(OwnCert, MasterSecret, 
 						 Version, HashSign, PrivateKey, Handshake0) of
         #certificate_verify{} = Verified ->
diff --git a/lib/ssl/src/ssl_handshake.erl b/lib/ssl/src/ssl_handshake.erl
index 9d251054c9..497f778bc2 100644
--- a/lib/ssl/src/ssl_handshake.erl
+++ b/lib/ssl/src/ssl_handshake.erl
@@ -927,7 +927,7 @@ dec_hs({Major, Minor}, ?CERTIFICATE_VERIFY,<<HashSign:2/binary, ?UINT16(SignLen)
   when Major == 3, Minor >= 3 ->
     #certificate_verify{hashsign_algorithm = hashsign_dec(HashSign), signature = Signature};
 dec_hs(_Version, ?CERTIFICATE_VERIFY,<<?UINT16(SignLen), Signature:SignLen/binary>>)->
-    #certificate_verify{hashsign_algorithm = {unknown, unknown}, signature = Signature};
+    #certificate_verify{signature = Signature};
 dec_hs(_Version, ?CLIENT_KEY_EXCHANGE, PKEPMS) ->
     #client_key_exchange{exchange_keys = PKEPMS};
 dec_hs(_Version, ?FINISHED, VerifyData) ->
diff --git a/lib/ssl/src/ssl_tls1.erl b/lib/ssl/src/ssl_tls1.erl
index 91b321bcd9..1daf9640ab 100644
--- a/lib/ssl/src/ssl_tls1.erl
+++ b/lib/ssl/src/ssl_tls1.erl
@@ -80,11 +80,11 @@ certificate_verify(md5sha, _Version, Handshake) ->
     SHA = crypto:sha(Handshake),
     <<MD5/binary, SHA/binary>>;
 
-certificate_verify(sha, _Version, Handshake) ->
-    crypto:sha(Handshake).
+certificate_verify(HashAlgo, _Version, Handshake) ->
+    Hash = crypto:hash(HashAlgo, Handshake).
 
 -spec setup_keys(integer(), integer(), binary(), binary(), binary(), integer(),
-		 integer(), integer()) -> {binary(), binary(), binary(), 
+		 integer(), integer()) -> {binary(), binary(), binary(),
 					  binary(), binary(), binary()}.  
 
 setup_keys(Version, _PrfAlgo, MasterSecret, ServerRandom, ClientRandom, HashSize,
-- 
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