Remove support for SSL_{CTX_}set_tmp_ecdh_callback().

This only gets used to set a specific curve without actually checking that the
peer supports it or not and can therefor result in handshake failures that can
be avoided by selecting a different cipher.

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>

CHANGES

@@ -13,6 +13,10 @@
      pages. This work was developed in partnership with Intel Corp.
      [Matt Caswell]
 
+  *) Remove support for SSL_{CTX_}set_tmp_ecdh_callback().  You should set the
+     curve you want to support using SSL_{CTX_}set1_curves().
+     [Kurt Roeckx]
+
   *) State machine rewrite. The state machine code has been significantly
      refactored in order to remove much duplication of code and solve issues
      with the old code (see ssl/statem/README for further details). This change

include/openssl/ssl.h

@@ -1119,7 +1119,6 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
 # define SSL_CTRL_SET_TMP_ECDH                   4
 # define SSL_CTRL_SET_TMP_RSA_CB                 5
 # define SSL_CTRL_SET_TMP_DH_CB                  6
-# define SSL_CTRL_SET_TMP_ECDH_CB                7
 # define SSL_CTRL_GET_SESSION_REUSED             8
 # define SSL_CTRL_GET_CLIENT_CERT_REQUEST        9
 # define SSL_CTRL_GET_NUM_RENEGOTIATIONS         10
@@ -1772,14 +1771,6 @@ void SSL_set_tmp_dh_callback(SSL *ssl,
                              DH *(*dh) (SSL *ssl, int is_export,
                                         int keylength));
 # endif
-# ifndef OPENSSL_NO_EC
-void SSL_CTX_set_tmp_ecdh_callback(SSL_CTX *ctx,
-                                   EC_KEY *(*ecdh) (SSL *ssl, int is_export,
-                                                    int keylength));
-void SSL_set_tmp_ecdh_callback(SSL *ssl,
-                               EC_KEY *(*ecdh) (SSL *ssl, int is_export,
-                                                int keylength));
-# endif
 
 __owur const COMP_METHOD *SSL_get_current_compression(SSL *s);
 __owur const COMP_METHOD *SSL_get_current_expansion(SSL *s);

ssl/s3_lib.c

@@ -4095,11 +4095,6 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
             ret = 1;
         }
         break;
-    case SSL_CTRL_SET_TMP_ECDH_CB:
-        {
-            SSLerr(SSL_F_SSL3_CTRL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
-            return (ret);
-        }
 #endif                          /* !OPENSSL_NO_EC */
     case SSL_CTRL_SET_TLSEXT_HOSTNAME:
         if (larg == TLSEXT_NAMETYPE_host_name) {
@@ -4422,13 +4417,6 @@ long ssl3_callback_ctrl(SSL *s, int cmd, void (*fp) (void))
             s->cert->dh_tmp_cb = (DH *(*)(SSL *, int, int))fp;
         }
         break;
-#endif
-#ifndef OPENSSL_NO_EC
-    case SSL_CTRL_SET_TMP_ECDH_CB:
-        {
-            s->cert->ecdh_tmp_cb = (EC_KEY *(*)(SSL *, int, int))fp;
-        }
-        break;
 #endif
     case SSL_CTRL_SET_TLSEXT_DEBUG_CB:
         s->tlsext_debug_cb = (void (*)(SSL *, int, int,
@@ -4558,11 +4546,6 @@ long ssl3_ctx_ctrl(SSL_CTX *ctx, int cmd, long larg, void *parg)
             return 1;
         }
         /* break; */
-    case SSL_CTRL_SET_TMP_ECDH_CB:
-        {
-            SSLerr(SSL_F_SSL3_CTX_CTRL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
-            return (0);
-        }
 #endif                          /* !OPENSSL_NO_EC */
     case SSL_CTRL_SET_TLSEXT_SERVERNAME_ARG:
         ctx->tlsext_servername_arg = parg;
@@ -4732,13 +4715,6 @@ long ssl3_ctx_callback_ctrl(SSL_CTX *ctx, int cmd, void (*fp) (void))
             cert->dh_tmp_cb = (DH *(*)(SSL *, int, int))fp;
         }
         break;
-#endif
-#ifndef OPENSSL_NO_EC
-    case SSL_CTRL_SET_TMP_ECDH_CB:
-        {
-            cert->ecdh_tmp_cb = (EC_KEY *(*)(SSL *, int, int))fp;
-        }
-        break;
 #endif
     case SSL_CTRL_SET_TLSEXT_SERVERNAME_CB:
         ctx->tlsext_servername_callback = (int (*)(SSL *, int *, void *))fp;

ssl/ssl_cert.c

@@ -239,7 +239,6 @@ CERT *ssl_cert_dup(CERT *cert)
             goto err;
         }
     }
-    ret->ecdh_tmp_cb = cert->ecdh_tmp_cb;
     ret->ecdh_tmp_auto = cert->ecdh_tmp_auto;
 #endif
 

ssl/ssl_lib.c

@@ -2037,7 +2037,7 @@ void ssl_set_masks(SSL *s, const SSL_CIPHER *cipher)
 #endif
 
 #ifndef OPENSSL_NO_EC
-    have_ecdh_tmp = (c->ecdh_tmp || c->ecdh_tmp_cb || c->ecdh_tmp_auto);
+    have_ecdh_tmp = (c->ecdh_tmp || c->ecdh_tmp_auto);
 #endif
     cpk = &(c->pkeys[SSL_PKEY_RSA_ENC]);
     rsa_enc = pvalid[SSL_PKEY_RSA_ENC] & CERT_PKEY_VALID;
@@ -3142,23 +3142,6 @@ void SSL_set_tmp_dh_callback(SSL *ssl, DH *(*dh) (SSL *ssl, int is_export,
 }
 #endif
 
-#ifndef OPENSSL_NO_EC
-void SSL_CTX_set_tmp_ecdh_callback(SSL_CTX *ctx,
-                                   EC_KEY *(*ecdh) (SSL *ssl, int is_export,
-                                                    int keylength))
-{
-    SSL_CTX_callback_ctrl(ctx, SSL_CTRL_SET_TMP_ECDH_CB,
-                          (void (*)(void))ecdh);
-}
-
-void SSL_set_tmp_ecdh_callback(SSL *ssl,
-                               EC_KEY *(*ecdh) (SSL *ssl, int is_export,
-                                                int keylength))
-{
-    SSL_callback_ctrl(ssl, SSL_CTRL_SET_TMP_ECDH_CB, (void (*)(void))ecdh);
-}
-#endif
-
 #ifndef OPENSSL_NO_PSK
 int SSL_CTX_use_psk_identity_hint(SSL_CTX *ctx, const char *identity_hint)
 {

ssl/ssl_locl.h

@@ -1570,8 +1570,6 @@ typedef struct cert_st {
 # endif
 # ifndef OPENSSL_NO_EC
     EC_KEY *ecdh_tmp;
-    /* Callback for generating ephemeral ECDH keys */
-    EC_KEY *(*ecdh_tmp_cb) (SSL *ssl, int is_export, int keysize);
     /* Select ECDH parameters automatically */
     int ecdh_tmp_auto;
 # endif

ssl/statem/statem_srvr.c

@@ -1874,12 +1874,6 @@ int tls_construct_server_key_exchange(SSL *s)
             int nid = tls1_shared_curve(s, -2);
             if (nid != NID_undef)
                 ecdhp = EC_KEY_new_by_curve_name(nid);
-        } else if ((ecdhp == NULL) && s->cert->ecdh_tmp_cb) {
-            ecdhp = s->cert->ecdh_tmp_cb(s,
-                                         SSL_C_IS_EXPORT(s->s3->
-                                                         tmp.new_cipher),
-                                         SSL_C_EXPORT_PKEYLENGTH(s->
-                                                                 s3->tmp.new_cipher));
         }
         if (ecdhp == NULL) {
             al = SSL_AD_HANDSHAKE_FAILURE;

ssl/t1_lib.c

@@ -868,8 +868,8 @@ int tls1_check_ec_tmp_key(SSL *s, unsigned long cid)
         /* Check this curve is acceptable */
         if (!tls1_check_ec_key(s, curve_id, NULL))
             return 0;
-        /* If auto or setting curve from callback assume OK */
+        /* If auto assume OK */
-        if (s->cert->ecdh_tmp_auto || s->cert->ecdh_tmp_cb)
+        if (s->cert->ecdh_tmp_auto)
             return 1;
         /* Otherwise check curve is acceptable */
         else {
@@ -892,10 +892,7 @@ int tls1_check_ec_tmp_key(SSL *s, unsigned long cid)
             return 0;
     }
     if (!ec) {
-        if (s->cert->ecdh_tmp_cb)
+        return 0;
-            return 1;
-        else
-            return 0;
     }
     if (!tls1_set_ec_id(curve_id, NULL, ec))
         return 0;

util/ssleay.num

@@ -217,8 +217,8 @@ SSL_renegotiate_pending                 265	EXIST::FUNCTION:
 SSL_CTX_set_msg_callback                266	EXIST::FUNCTION:
 SSL_set_msg_callback                    267	EXIST::FUNCTION:
 DTLSv1_client_method                    268	EXIST::FUNCTION:
-SSL_CTX_set_tmp_ecdh_callback           269	EXIST::FUNCTION:EC
+SSL_CTX_set_tmp_ecdh_callback           269	NOEXIST::FUNCTION:
-SSL_set_tmp_ecdh_callback               270	EXIST::FUNCTION:EC
+SSL_set_tmp_ecdh_callback               270	NOEXIST::FUNCTION:
 SSL_COMP_get_name                       271	EXIST::FUNCTION:
 SSL_get_current_compression             272	EXIST::FUNCTION:
 DTLSv1_method                           273	EXIST::FUNCTION: