From 55a47cd30f064284e5b1f477d5a358938b5f71aa Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Mon, 30 May 2011 17:58:29 +0000
Subject: [PATCH] Output supported curves in preference order instead of
 numerically.

---
 CHANGES      |  5 +++++
 ssl/t1_lib.c | 43 ++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/CHANGES b/CHANGES
index fdf1d006d2..e45caddc03 100644
--- a/CHANGES
+++ b/CHANGES
@@ -14,6 +14,11 @@
      for static and shared library builds embedding a signature if needed.
      [Steve Henson]
 
+  *) Output TLS supported curves in preference order instead of numerical
+     order. This is currently hardcoded for the highest order curves first.
+     This should be configurable so applications can judge speed vs strength.
+     [Steve Henson]
+
   *) Add protection against ECDSA timing attacks as mentioned in the paper
      by Billy Bob Brumley and Nicola Tuveri, see:
 
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 1dbdc0183c..ac9931d7f2 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -170,6 +170,7 @@ void tls1_clear(SSL *s)
 	}
 
 #ifndef OPENSSL_NO_EC
+
 static int nid_list[] =
 	{
 		NID_sect163k1, /* sect163k1 (1) */
@@ -198,7 +199,36 @@ static int nid_list[] =
 		NID_secp384r1, /* secp384r1 (24) */
 		NID_secp521r1  /* secp521r1 (25) */	
 	};
-	
+
+static int pref_list[] =
+	{
+		NID_sect571r1, /* sect571r1 (14) */ 
+		NID_sect571k1, /* sect571k1 (13) */ 
+		NID_secp521r1, /* secp521r1 (25) */	
+		NID_sect409k1, /* sect409k1 (11) */ 
+		NID_sect409r1, /* sect409r1 (12) */
+		NID_secp384r1, /* secp384r1 (24) */
+		NID_sect283k1, /* sect283k1 (9) */
+		NID_sect283r1, /* sect283r1 (10) */ 
+		NID_secp256k1, /* secp256k1 (22) */ 
+		NID_X9_62_prime256v1, /* secp256r1 (23) */ 
+		NID_sect239k1, /* sect239k1 (8) */ 
+		NID_sect233k1, /* sect233k1 (6) */
+		NID_sect233r1, /* sect233r1 (7) */ 
+		NID_secp224k1, /* secp224k1 (20) */ 
+		NID_secp224r1, /* secp224r1 (21) */
+		NID_sect193r1, /* sect193r1 (4) */ 
+		NID_sect193r2, /* sect193r2 (5) */ 
+		NID_secp192k1, /* secp192k1 (18) */
+		NID_X9_62_prime192v1, /* secp192r1 (19) */ 
+		NID_sect163k1, /* sect163k1 (1) */
+		NID_sect163r1, /* sect163r1 (2) */
+		NID_sect163r2, /* sect163r2 (3) */
+		NID_secp160k1, /* secp160k1 (15) */
+		NID_secp160r1, /* secp160r1 (16) */ 
+		NID_secp160r2, /* secp160r2 (17) */ 
+	};
+
 int tls1_ec_curve_id2nid(int curve_id)
 	{
 	/* ECC curves from draft-ietf-tls-ecc-12.txt (Oct. 17, 2005) */
@@ -1375,16 +1405,19 @@ int ssl_prepare_clienthello_tlsext(SSL *s)
 
 		/* we support all named elliptic curves in draft-ietf-tls-ecc-12 */
 		if (s->tlsext_ellipticcurvelist != NULL) OPENSSL_free(s->tlsext_ellipticcurvelist);
-		s->tlsext_ellipticcurvelist_length = sizeof(nid_list)/sizeof(nid_list[0]) * 2;
+		s->tlsext_ellipticcurvelist_length = sizeof(pref_list)/sizeof(pref_list[0]) * 2;
 		if ((s->tlsext_ellipticcurvelist = OPENSSL_malloc(s->tlsext_ellipticcurvelist_length)) == NULL)
 			{
 			s->tlsext_ellipticcurvelist_length = 0;
 			SSLerr(SSL_F_SSL_PREPARE_CLIENTHELLO_TLSEXT,ERR_R_MALLOC_FAILURE);
 			return -1;
 			}
-		for (i = 1, j = s->tlsext_ellipticcurvelist; (unsigned int)i <=
-				sizeof(nid_list)/sizeof(nid_list[0]); i++)
-			s2n(i,j);
+		for (i = 0, j = s->tlsext_ellipticcurvelist; (unsigned int)i <
+				sizeof(pref_list)/sizeof(pref_list[0]); i++)
+			{
+			int id = tls1_ec_nid2curve_id(pref_list[i]);
+			s2n(id,j);
+			}
 		}
 #endif /* OPENSSL_NO_EC */
 
-- 
2.34.1