From: Nikos Mavrogiannopoulos <nmav@gnutls.org>
Date: Wed, 3 Mar 2010 10:50:50 +0000 (+0100)
Subject: Avoid sending alerts during handshake. Alerts might be interrupted and return
X-Git-Tag: gnutls_2_9_10~60
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=67ff3f2cedabcf1a831129466360280cd571ab85;p=thirdparty%2Fgnutls.git

Avoid sending alerts during handshake. Alerts might be interrupted and return
a non-fatal error which will propagate and in many cases it shouldn't.

Avoid sending no renegotiation alert when a client connects to an unsafe server. Thanks
to Tomas Hoger for the report.
---

diff --git a/lib/gnutls_alert.c b/lib/gnutls_alert.c
index f4c52875c5..71aae45f5c 100644
--- a/lib/gnutls_alert.c
+++ b/lib/gnutls_alert.c
@@ -181,6 +181,10 @@ gnutls_error_to_alert (int err, int *level)
       ret = GNUTLS_A_ILLEGAL_PARAMETER;
       _level = GNUTLS_AL_FATAL;
       break;
+    case GNUTLS_E_UNKNOWN_SRP_USERNAME:
+      ret = GNUTLS_A_UNKNOWN_PSK_IDENTITY;
+      _level = GNUTLS_AL_FATAL;
+      break;
     case GNUTLS_E_ASN1_ELEMENT_NOT_FOUND:
     case GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND:
     case GNUTLS_E_ASN1_DER_ERROR:
@@ -215,6 +219,7 @@ gnutls_error_to_alert (int err, int *level)
       _level = GNUTLS_AL_FATAL;
       break;
     case GNUTLS_E_REHANDSHAKE:
+    case GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED:
       ret = GNUTLS_A_NO_RENEGOTIATION;
       _level = GNUTLS_AL_WARNING;
       break;
diff --git a/lib/gnutls_errors.c b/lib/gnutls_errors.c
index 69d92ad2de..21f40b1cc1 100644
--- a/lib/gnutls_errors.c
+++ b/lib/gnutls_errors.c
@@ -223,9 +223,13 @@ static const gnutls_error_entry error_algorithms[] = {
 	       GNUTLS_E_OPENPGP_SUBKEY_ERROR, 1),
   ERROR_ENTRY (N_("Safe renegotiation failed."),
 	       GNUTLS_E_SAFE_RENEGOTIATION_FAILED, 1),
+  ERROR_ENTRY (N_("Unsafe renegotiation denied."),
+	       GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED, 1),
 
   ERROR_ENTRY (N_("The SRP username supplied is illegal."),
 	       GNUTLS_E_ILLEGAL_SRP_USERNAME, 1),
+  ERROR_ENTRY (N_("The SRP username supplied is unknown."),
+	       GNUTLS_E_UNKNOWN_SRP_USERNAME, 1),
 
   ERROR_ENTRY (N_("The OpenPGP fingerprint is not supported."),
 	       GNUTLS_E_OPENPGP_FINGERPRINT_UNSUPPORTED, 1),
diff --git a/lib/gnutls_handshake.c b/lib/gnutls_handshake.c
index 4e2952a405..2ed4f5cae4 100644
--- a/lib/gnutls_handshake.c
+++ b/lib/gnutls_handshake.c
@@ -2248,15 +2248,7 @@ _gnutls_send_server_hello (gnutls_session_t session, int again)
 	   * alert and abort.
 	   */
 	  gnutls_assert ();
-	  ret = gnutls_alert_send (session, GNUTLS_AL_FATAL,
-				   GNUTLS_A_UNKNOWN_PSK_IDENTITY);
-	  if (ret < 0)
-	    {
-	      gnutls_assert ();
-	      return ret;
-	    }
-
-	  return GNUTLS_E_ILLEGAL_SRP_USERNAME;
+	  return GNUTLS_E_UNKNOWN_SRP_USERNAME;
 	}
     }
 #endif
@@ -2435,22 +2427,16 @@ _gnutls_recv_hello (gnutls_session_t session, opaque * data, int datalen)
 	{
 	  if (session->internals.priorities.unsafe_renegotiation != 0)
 	    {
-	      _gnutls_handshake_log ("Allowing unsafe renegotiation!\n");
+	      _gnutls_handshake_log ("Allowing unsafe (re)negotiation!\n");
 	    }
 	  else
 	    {
 	      gnutls_assert();
-	      _gnutls_handshake_log ("Denying unsafe renegotiation.\n");
-	      ret = gnutls_alert_send (session, GNUTLS_AL_WARNING,
-				   GNUTLS_A_NO_RENEGOTIATION);
-
-  	      if (ret < 0)
-	        {
-	          gnutls_assert ();
-	          return ret;
-	        }
-
-	      return GNUTLS_E_SAFE_RENEGOTIATION_FAILED;
+	      _gnutls_handshake_log ("Denying unsafe (re)negotiation.\n");
+	      if (session->security_parameters.entity == GNUTLS_SERVER)
+	        return GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED; /* send no renegotiation alert */
+              else
+ 	        return GNUTLS_E_SAFE_RENEGOTIATION_FAILED;
 	    }
 	}
       else
diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index c3b6262320..8f3d828b08 100644
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -1685,6 +1685,8 @@ extern "C" {
 #define GNUTLS_E_UNKNOWN_ALGORITHM -105
 #define GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM -106
 #define GNUTLS_E_SAFE_RENEGOTIATION_FAILED -107
+#define GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED -108
+#define GNUTLS_E_UNKNOWN_SRP_USERNAME -109
 
 #define GNUTLS_E_BASE64_ENCODING_ERROR -201
 #define GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY -202	/* obsolete */