Make supported_groups code independent of EC and DH

The supported groups code was checking the OPENSSL_NO_EC and
OPENSSL_NO_DH guards in order to work, and the list of default groups was
based on those guards. However we now need it to work even in a no-ec
and no-dh build, because new groups might be added from providers.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13916)

2 files changed, 20 insertions, 12 deletions

diff --git a/ssl/statem/extensions_clnt.c b/ssl/statem/extensions_clnt.c
index 89e1422bbd..cc958aa1b0 100644
--- a/ssl/statem/extensions_clnt.c
+++ b/ssl/statem/extensions_clnt.c
@@ -108,7 +108,6 @@ EXT_RETURN tls_construct_ctos_srp(SSL *s, WPACKET *pkt, unsigned int context,
 }
 #endif
 
-#ifndef OPENSSL_NO_EC
 static int use_ecc(SSL *s, int min_version, int max_version)
 {
     int i, end, ret = 0;
@@ -144,7 +143,7 @@ static int use_ecc(SSL *s, int min_version, int max_version)
     for (j = 0; j < num_groups; j++) {
         uint16_t ctmp = pgroups[j];
 
-        if (tls_valid_group(s, ctmp, min_version, max_version)
+        if (tls_valid_group(s, ctmp, min_version, max_version, 1, NULL)
                 && tls_group_allowed(s, ctmp, SSL_SECOP_CURVE_SUPPORTED))
             return 1;
     }
@@ -152,6 +151,7 @@ static int use_ecc(SSL *s, int min_version, int max_version)
     return 0;
 }
 
+#ifndef OPENSSL_NO_EC
 EXT_RETURN tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt,
                                             unsigned int context, X509 *x,
                                             size_t chainidx)
@@ -189,7 +189,7 @@ EXT_RETURN tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
                                                size_t chainidx)
 {
     const uint16_t *pgroups = NULL;
-    size_t num_groups = 0, i;
+    size_t num_groups = 0, i, tls13added = 0, added = 0;
     int min_version, max_version, reason;
 
     reason = ssl_get_min_max_version(s, &min_version, &max_version, NULL);
@@ -198,13 +198,13 @@ EXT_RETURN tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
         return EXT_RETURN_FAIL;
     }
 
-#if defined(OPENSSL_NO_EC)
-    if (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION)
-        return EXT_RETURN_NOT_SENT;
-#else
-    if (!use_ecc(s, min_version, max_version) && max_version < TLS1_3_VERSION)
+    /*
+     * We only support EC groups in TLSv1.2 or below, and in DTLS. Therefore
+     * if we don't have EC support then we don't send this extension.
+     */
+    if (!use_ecc(s, min_version, max_version)
+            && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
         return EXT_RETURN_NOT_SENT;
-#endif
 
     /*
      * Add TLS extension supported_groups to the ClientHello message
@@ -222,17 +222,25 @@ EXT_RETURN tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
     /* Copy group ID if supported */
     for (i = 0; i < num_groups; i++) {
         uint16_t ctmp = pgroups[i];
+        int okfortls13;
 
-        if (tls_valid_group(s, ctmp, min_version, max_version)
+        if (tls_valid_group(s, ctmp, min_version, max_version, 0, &okfortls13)
                 && tls_group_allowed(s, ctmp, SSL_SECOP_CURVE_SUPPORTED)) {
             if (!WPACKET_put_bytes_u16(pkt, ctmp)) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
                 return EXT_RETURN_FAIL;
             }
+            if (okfortls13 && max_version == TLS1_3_VERSION)
+                tls13added++;
+            added++;
         }
     }
     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
-        SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
+        if (added == 0 || (tls13added == 0 && max_version == TLS1_3_VERSION))
+            SSLfatal_data(s, SSL_AD_INTERNAL_ERROR, SSL_R_NO_SUITABLE_GROUPS,
+                          "No groups enabled for max supported SSL/TLS version");
+        else
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
         return EXT_RETURN_FAIL;
     }
 
diff --git a/ssl/statem/extensions_srvr.c b/ssl/statem/extensions_srvr.c
index 99cd515386..42fd6ee7d3 100644
--- a/ssl/statem/extensions_srvr.c
+++ b/ssl/statem/extensions_srvr.c
@@ -1355,7 +1355,7 @@ EXT_RETURN tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
     for (i = 0; i < numgroups; i++) {
         uint16_t group = groups[i];
 
-        if (tls_valid_group(s, group, version, version)
+        if (tls_valid_group(s, group, version, version, 0, NULL)
                 && tls_group_allowed(s, group, SSL_SECOP_CURVE_SUPPORTED)) {
             if (first) {
                 /*