Add tls-groups configuration directive and CLI support for TLS named groups

src/cli_common.c

@@ -101,6 +101,12 @@ int cliSecureConnection(valkeyContext *c, cliSSLconfig config, const char **err)
             *err = "Error while setting cypher suites";
             goto error;
         }
+#endif
+#if CLI_TLS_SUPPORTS_GROUPS
+        if (config.groups && !cliSslCtxSetGroupsList(ssl_ctx, config.groups)) {
+            *err = "Error while configuring TLS groups";
+            goto error;
+        }
 #endif
     }
 

src/cli_common.h

@@ -5,6 +5,25 @@
 #include "sds.h"
 #include <stdint.h>
 
+/* TLS named groups configuration.
+ * CLI_TLS_SUPPORTS_GROUPS is enabled when OpenSSL supports setting named groups.
+ * Define TLS_NO_GROUPS at build time to disable. */
+#ifdef USE_OPENSSL
+#include <openssl/ssl.h>
+#endif
+
+#if defined(TLS_NO_GROUPS)
+#define CLI_TLS_SUPPORTS_GROUPS 0
+#elif defined(SSL_CTX_set1_groups_list)
+#define CLI_TLS_SUPPORTS_GROUPS 1
+#define cliSslCtxSetGroupsList(ctx, list) SSL_CTX_set1_groups_list((ctx), (list))
+#elif defined(SSL_CTX_set1_curves_list)
+#define CLI_TLS_SUPPORTS_GROUPS 1
+#define cliSslCtxSetGroupsList(ctx, list) SSL_CTX_set1_curves_list((ctx), (list))
+#else
+#define CLI_TLS_SUPPORTS_GROUPS 0
+#endif
+
 typedef struct cliSSLconfig {
     /* Requested SNI, or NULL */
     char *sni;
@@ -22,6 +41,8 @@ typedef struct cliSSLconfig {
     char *ciphers;
     /* Preferred ciphersuites list, or NULL (applies only to TLSv1.3) */
     char *ciphersuites;
+    /* Colon-separated named groups for key exchange (--tls-groups), or NULL */
+    char *groups;
 } cliSSLconfig;
 
 

src/config.c

@@ -3716,6 +3716,7 @@ standardConfig static_configs[] = {
     createStringConfig("tls-protocols", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.protocols, NULL, NULL, applyTlsCfg),
     createStringConfig("tls-ciphers", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.ciphers, NULL, NULL, applyTlsCfg),
     createStringConfig("tls-ciphersuites", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.ciphersuites, NULL, NULL, applyTlsCfg),
+    createStringConfig("tls-groups", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.groups, NULL, NULL, applyTlsCfg),
 
     /* Special configs */
     createSpecialConfig("dir", NULL, MODIFIABLE_CONFIG | PROTECTED_CONFIG | DENY_LOADING_CONFIG, setConfigDirOption, getConfigDirOption, rewriteConfigDirOption, NULL),

src/server.h

@@ -1796,6 +1796,7 @@ typedef struct serverTLSContextConfig {
     char *protocols;
     char *ciphers;
     char *ciphersuites;
+    char *groups;             /* TLS key-exchange groups (e.g. X25519MLKEM768/x25519) */
     int prefer_server_ciphers;
     int session_caching;
     int session_cache_size;

src/tls.c

@@ -73,6 +73,27 @@
 #define REDIS_TLS_PROTO_DEFAULT (REDIS_TLS_PROTO_TLSv1_2)
 #endif
 
+/* Support for TLS key-exchange groups (named groups / curves).
+ *
+ * CONN_TLS_SUPPORTS_GROUPS is enabled when OpenSSL provides an API to configure
+ * named groups on an SSL context (SSL_CTX_set1_groups_list or the older
+ * SSL_CTX_set1_curves_list alias).
+ *
+ * Define TLS_NO_GROUPS to compile without group configuration support.
+ * If neither API is present and TLS_NO_GROUPS is not set, a compile-time
+ * error is raised so that an operator-requested group list is not silently ignored. */
+#if defined(TLS_NO_GROUPS)
+#define CONN_TLS_SUPPORTS_GROUPS 0
+#elif defined(SSL_CTX_set1_groups_list)
+#define CONN_TLS_SUPPORTS_GROUPS 1
+#define valkeyTlsCtxSetGroupsList(ctx, list) SSL_CTX_set1_groups_list((ctx), (list))
+#elif defined(SSL_CTX_set1_curves_list)
+#define CONN_TLS_SUPPORTS_GROUPS 1
+#define valkeyTlsCtxSetGroupsList(ctx, list) SSL_CTX_set1_curves_list((ctx), (list))
+#else
+#error "tls-groups requires SSL_CTX_set1_groups_list or SSL_CTX_set1_curves_list. Build with -DTLS_NO_GROUPS to disable."
+#endif
+
 SSL_CTX *valkey_tls_ctx = NULL;
 SSL_CTX *valkey_tls_client_ctx = NULL;
 
@@ -734,6 +755,20 @@ static SSL_CTX *createSSLContext(serverTLSContextConfig *ctx_config, int protoco
     }
 #endif
 
+#if CONN_TLS_SUPPORTS_GROUPS
+    if (ctx_config->groups && !valkeyTlsCtxSetGroupsList(ctx, ctx_config->groups)) {
+        serverLog(LL_WARNING, "Failed to configure TLS groups: %s", ctx_config->groups);
+        goto error;
+    }
+#else
+    if (ctx_config->groups) {
+        serverLog(LL_WARNING, "tls-groups is configured but this build does not support "
+                              "setting TLS groups; recompile without -DTLS_NO_GROUPS "
+                              "or upgrade OpenSSL");
+        goto error;
+    }
+#endif
+
     /* Loading the alternate certificate moved the current certificate to its slot,
      * and outgoing TLS 1.2 connections pick their client certificate from there.
      * Leave it on the lowest slot, which is where it sat before dual certificates. */

src/valkey-benchmark.c

@@ -2003,6 +2003,11 @@ int parseOptions(int argc, char **argv) {
             if (lastarg) goto invalid;
             config.sslconfig.ciphersuites = strdup(argv[++i]);
 #endif
+#if CLI_TLS_SUPPORTS_GROUPS
+        } else if (!strcmp(argv[i], "--tls-groups")) {
+            if (lastarg) goto invalid;
+            config.sslconfig.groups = strdup(argv[++i]);
+#endif
 #endif
 #ifdef USE_RDMA
         } else if (!strcmp(argv[i], "--rdma")) {
@@ -2076,6 +2081,11 @@ int parseOptions(int argc, char **argv) {
         "                    information about the syntax of this string, and\n"
         "                    specifically for TLSv1.3 ciphersuites.\n"
 #endif
+#if CLI_TLS_SUPPORTS_GROUPS
+        " --tls-groups <list> Sets the list of preferred TLS groups\n"
+        "                    in order of preference from highest to lowest separated by colon (':').\n"
+        "                    See the SSL_CTX_set1_groups_list(3ssl) manpage for syntax.\n"
+#endif
 #endif
         "";
 

src/valkey-cli.c

@@ -2852,6 +2852,10 @@ static int parseOptions(int argc, char **argv) {
         } else if (!strcmp(argv[i], "--tls-ciphersuites") && !lastarg) {
             config.sslconfig.ciphersuites = argv[++i];
 #endif
+#if CLI_TLS_SUPPORTS_GROUPS
+        } else if (!strcmp(argv[i], "--tls-groups") && !lastarg) {
+            config.sslconfig.groups = argv[++i];
+#endif
 #endif
 #ifdef USE_RDMA
         } else if (!strcmp(argv[i], "--rdma")) {
@@ -3005,6 +3009,11 @@ static void usage(int err) {
         "                     See the ciphers(1ssl) manpage for more information about the syntax of this string,\n"
         "                     and specifically for TLSv1.3 ciphersuites.\n"
 #endif
+#if CLI_TLS_SUPPORTS_GROUPS
+        "  --tls-groups <list> Sets the list of preferred TLS groups\n"
+        "                     in order of preference from highest to lowest separated by colon (':').\n"
+        "                     See the SSL_CTX_set1_groups_list(3ssl) manpage for syntax.\n"
+#endif
 #endif
         "";
     const char *rdma_usage =

tests/unit/introspection.tcl

@@ -1397,6 +1397,7 @@ start_server {tags {"introspection"}} {
                 tls-protocols
                 tls-ciphers
                 tls-ciphersuites
+                tls-groups
                 tls-port
             }
         }

tests/unit/tls.tcl

@@ -84,6 +84,70 @@ start_server {tags {"tls"}} {
             r CONFIG SET tls-ciphers "DEFAULT"
         }
 
+        proc check_tls_groups_supported {} {
+            if {[catch {r CONFIG SET tls-groups prime256v1}] &&
+                [count_log_message 0 "this build does not support"] > 0} {
+                skip "tls-groups not supported in this build (TLS_NO_GROUPS)"
+            }
+            r CONFIG SET tls-groups ""
+        }
+
+        # Helper: run valkey-cli with a specific tls-groups value and return output.
+        # Uses ECDHE-RSA-AES128-GCM-SHA256 so we can test TLSv1.2 group selection
+        # independently of the cipher negotiation.
+        proc connect_with_tls_groups {host port groups} {
+            set cli_cmd [list $::VALKEY_CLI_BIN \
+                -h $host -p $port \
+                {*}[valkeycli_tls_config "./tests"] \
+                --tls-ciphers ECDHE-RSA-AES128-GCM-SHA256 \
+                --tls-groups $groups PING]
+            exec {*}$cli_cmd 2>@1
+        }
+
+        test {TLS: tls-groups rejects invalid group names at CONFIG SET time} {
+            check_tls_groups_supported
+
+            catch {r CONFIG SET tls-groups "invalid-group"} e
+            assert_match {*Unable to update TLS configuration*} $e
+
+            r CONFIG SET tls-groups ""
+        }
+
+        test {TLS: tls-groups with overlapping groups completes handshake} {
+            check_tls_groups_supported
+
+            set ecdhe_ciphers ECDHE-RSA-AES128-GCM-SHA256
+            r CONFIG SET tls-protocols TLSv1.2
+            r CONFIG SET tls-ciphers $ecdhe_ciphers
+            r CONFIG SET tls-groups prime256v1
+
+            # Server is restricted to prime256v1; client requests the same
+            # group, so TLS negotiation must succeed without HRR.
+            assert_equal {PONG} [connect_with_tls_groups [srv 0 host] [srv 0 port] prime256v1]
+
+            r CONFIG SET tls-groups ""
+            r CONFIG SET tls-protocols ""
+            r CONFIG SET tls-ciphers DEFAULT
+        }
+
+        test {TLS: tls-groups with no shared group causes handshake failure} {
+            check_tls_groups_supported
+
+            set ecdhe_ciphers ECDHE-RSA-AES128-GCM-SHA256
+            r CONFIG SET tls-protocols TLSv1.2
+            r CONFIG SET tls-ciphers $ecdhe_ciphers
+            r CONFIG SET tls-groups prime256v1
+
+            # Server allows only prime256v1; client offers only secp384r1.
+            # No group is common so the server must reject the handshake.
+            assert_equal 1 [catch {connect_with_tls_groups [srv 0 host] [srv 0 port] secp384r1} e]
+            assert_match {*alert handshake failure*} $e
+
+            r CONFIG SET tls-groups ""
+            r CONFIG SET tls-protocols ""
+            r CONFIG SET tls-ciphers DEFAULT
+        }
+
         test {TLS: Verify tls-prefer-server-ciphers behaves as expected} {
             r CONFIG SET tls-protocols TLSv1.2
             r CONFIG SET tls-ciphers "AES128-SHA256:AES256-SHA256"

valkey.conf

@@ -325,6 +325,16 @@ tcp-keepalive 300
 #
 # tls-ciphersuites TLS_CHACHA20_POLY1305_SHA256
 
+# Configure TLS named group preferences for key exchange. The value is passed
+# directly to OpenSSL, so it accepts the syntax supported by
+# SSL_CTX_set1_groups_list(3ssl). Groups within the same security tier are
+# separated by ":" and different tiers by "/". Hybrid post-quantum groups
+# (e.g. X25519MLKEM768) should be listed before classical fallbacks.
+#
+# Example enabling PQC hybrid key exchange with classical fallback:
+#
+# tls-groups X25519MLKEM768/x25519
+
 # When choosing a cipher, use the server's preference instead of the client
 # preference. By default, the server follows the client's preference.
 #