Always enable ecdh_auto.
This is a really dumb API wart. Now that we have a limited set of curves that
are all reasonable, the automatic logic should just always kick in. This makes
set_ecdh_auto a no-op and, instead of making it the first choice, uses it as
the fallback behavior should none of the older curve selection APIs be used.
Currently, by default, server sockets can only use the plain RSA key exchange.
BUG=481139
Change-Id: Iaabc82de766cd00968844a71aaac29bd59841cd4
Reviewed-on: https://boringssl-review.googlesource.com/4531
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 7e086c1..18967fb 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -1650,7 +1650,6 @@
#define SSL_CTRL_GET_CURVES 90
#define SSL_CTRL_SET_CURVES 91
#define SSL_CTRL_SET_CURVES_LIST 92
-#define SSL_CTRL_SET_ECDH_AUTO 94
#define SSL_CTRL_SET_SIGALGS 97
#define SSL_CTRL_SET_SIGALGS_LIST 98
#define SSL_CTRL_CERT_FLAGS 99
@@ -1711,6 +1710,12 @@
SSL_CTX_ctrl(ctx, SSL_CTRL_SET_TMP_RSA, 0, (char *)rsa)
#define SSL_CTX_set_tmp_dh(ctx, dh) \
SSL_CTX_ctrl(ctx, SSL_CTRL_SET_TMP_DH, 0, (char *)dh)
+
+/* SSL_CTX_set_tmp_ecdh configures |ctx| to use the curve from |ecdh| (a const
+ * EC_KEY *) as the curve for ephemeral ECDH keys. For historical reasons, this
+ * API expects an |EC_KEY|, but only the curve is used. It returns one on
+ * success and zero on error. If unset, an appropriate curve will be chosen
+ * automatically. (This is recommended.) */
#define SSL_CTX_set_tmp_ecdh(ctx, ecdh) \
SSL_CTX_ctrl(ctx, SSL_CTRL_SET_TMP_ECDH, 0, (char *)ecdh)
@@ -1719,6 +1724,12 @@
SSL_ctrl(ssl, SSL_CTRL_SET_TMP_RSA, 0, (char *)rsa)
#define SSL_set_tmp_dh(ssl, dh) \
SSL_ctrl(ssl, SSL_CTRL_SET_TMP_DH, 0, (char *)dh)
+
+/* SSL_set_tmp_ecdh configures |ssl| to use the curve from |ecdh| (a const
+ * EC_KEY *) as the curve for ephemeral ECDH keys. For historical reasons, this
+ * API expects an |EC_KEY|, but only the curve is used. It returns one on
+ * success and zero on error. If unset, an appropriate curve will be chosen
+ * automatically. (This is recommended.) */
#define SSL_set_tmp_ecdh(ssl, ecdh) \
SSL_ctrl(ssl, SSL_CTRL_SET_TMP_ECDH, 0, (char *)ecdh)
@@ -1809,10 +1820,6 @@
SSL_ctrl(ctx, SSL_CTRL_SET_CURVES, clistlen, (char *)clist)
#define SSL_set1_curves_list(ctx, s) \
SSL_ctrl(ctx, SSL_CTRL_SET_CURVES_LIST, 0, (char *)s)
-#define SSL_CTX_set_ecdh_auto(ctx, onoff) \
- SSL_CTX_ctrl(ctx, SSL_CTRL_SET_ECDH_AUTO, onoff, NULL)
-#define SSL_set_ecdh_auto(s, onoff) \
- SSL_ctrl(s, SSL_CTRL_SET_ECDH_AUTO, onoff, NULL)
#define SSL_CTX_set1_sigalgs(ctx, slist, slistlen) \
SSL_CTX_ctrl(ctx, SSL_CTRL_SET_SIGALGS, slistlen, (int *)slist)
@@ -2201,10 +2208,34 @@
OPENSSL_EXPORT void SSL_set_tmp_dh_callback(SSL *ssl,
DH *(*dh)(SSL *ssl, int is_export,
int keylength));
+
+/* SSL_CTX_set_tmp_ecdh_callback configures |ctx| to use |callback| to determine
+ * the curve for ephemeral ECDH keys. |callback| should ignore |is_export| and
+ * |keylength| and return an |EC_KEY| of the selected curve or NULL on
+ * error. Only the curve is used, so the |EC_KEY| needn't have a generated
+ * keypair.
+ *
+ * If the callback is unset, an appropriate curve will be chosen automatically.
+ * (This is recommended.)
+ *
+ * WARNING: The caller does not take ownership of the resulting |EC_KEY|, so
+ * |callback| must save and release the object elsewhere. */
OPENSSL_EXPORT void SSL_CTX_set_tmp_ecdh_callback(
- SSL_CTX *ctx, EC_KEY *(*ecdh)(SSL *ssl, int is_export, int keylength));
+ SSL_CTX *ctx, EC_KEY *(*callback)(SSL *ssl, int is_export, int keylength));
+
+/* SSL_set_tmp_ecdh_callback configures |ssl| to use |callback| to determine the
+ * curve for ephemeral ECDH keys. |callback| should ignore |is_export| and
+ * |keylength| and return an |EC_KEY| of the selected curve or NULL on
+ * error. Only the curve is used, so the |EC_KEY| needn't have a generated
+ * keypair.
+ *
+ * If the callback is unset, an appropriate curve will be chosen automatically.
+ * (This is recommended.)
+ *
+ * WARNING: The caller does not take ownership of the resulting |EC_KEY|, so
+ * |callback| must save and release the object elsewhere. */
OPENSSL_EXPORT void SSL_set_tmp_ecdh_callback(
- SSL *ssl, EC_KEY *(*ecdh)(SSL *ssl, int is_export, int keylength));
+ SSL *ssl, EC_KEY *(*callback)(SSL *ssl, int is_export, int keylength));
OPENSSL_EXPORT const void *SSL_get_current_compression(SSL *s);
OPENSSL_EXPORT const void *SSL_get_current_expansion(SSL *s);
@@ -2291,6 +2322,12 @@
OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_server_method(void);
OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_client_method(void);
+/* SSL_CTX_set_ecdh_auto returns one. */
+#define SSL_CTX_set_ecdh_auto(ctx, onoff) 1
+
+/* SSL_set_ecdh_auto returns one. */
+#define SSL_set_ecdh_auto(ssl, onoff) 1
+
/* Android compatibility section.
*
