CONC-748: Allow to set TLSv1.3 ciphers in GnuTLS

- Added TLSv1.3 ciphers to cipher map.
- Fixed retrieval of cipher suite: Since gnutls_cipher_suite_get_name
  supports only TLSv1.2 (and lower) cipher suites, we have to call
  gnutls_ciphersuite_get() (requires GnuTLS 3.7.4 or newer).

libmariadb/secure/gnutls.c

@@ -723,6 +723,26 @@ const struct st_cipher_map tls_ciphers[]=
     "TLS_DH_anon_WITH_AES_256_GCM_SHA384",
      NULL,
     "TLS_DH_ANON_AES_256_GCM_SHA384"},
+  { {0x13, 0x01},
+    "TLS_AES_128_GCM_SHA256",
+    "TLS_AES_128_GCM_SHA256",
+    "TLS_AES_128_GCM_SHA256"},
+  { {0x13, 0x02},
+    "TLS_AES_256_GCM_SHA384",
+    "TLS_AES_256_GCM_SHA384",
+    "TLS_AES_256_GCM_SHA384"},
+  { {0x13, 0x03},
+    "TLS_CHACHA20_POLY1305_SHA256",
+    "TLS_CHACHA20_POLY1305_SHA256",
+    "TLS_CHACHA20_POLY1305_SHA256"},
+  { {0x13, 0x04},
+    "TLS_AES_128_CCM_SHA256",
+    "TLS_AES_128_CCM_SHA256",
+    "TLS_AES_128_CCM_SHA256"},
+  { {0x13, 0x05},
+    "TLS_AES_128_CCM_8_SHA256",
+    "TLS_AES_128_CCM_8_SHA256",
+    "TLS_AES_128_CCM_8_SHA256"},
   { {0xC0, 0x84},
     "TLS_DH_anon_WITH_CAMELLIA_128_GCM_SHA256",
      NULL,
@@ -793,6 +813,7 @@ const struct st_cipher_map tls_ciphers[]=
     NULL}
 };
 
+#if GNUTLS_VERSION_NUMBER < 0x030704
 /* map the gnutls cipher suite (defined by key exchange algorithm, cipher
    and mac algorithm) to the corresponding OpenSSL cipher name */
 static const char *openssl_cipher_name(gnutls_kx_algorithm_t kx,
@@ -829,6 +850,7 @@ static const char *openssl_cipher_name(gnutls_kx_algorithm_t kx,
   }
   return NULL;
 }
+#endif
 
 /* get priority string for a given openssl cipher name */
 static char *get_priority(const char *cipher_name, char *priority, size_t len)
@@ -857,10 +879,20 @@ static char *get_priority(const char *cipher_name, char *priority, size_t len)
       {
         if (!strcmp(name, tls_ciphers[i].gnutls_name))
         {
-          snprintf(priority, len - 1, ":+%s:+%s:+%s",
+          const char *p;
-                   gnutls_cipher_get_name(cipher),
+
-                   gnutls_mac_get_name(mac),
+          if ((p= gnutls_cipher_get_name(cipher)))
-                   gnutls_kx_get_name(kx));
+            snprintf(priority, len - 1, ":+%s",p);
+          if ((p= gnutls_mac_get_name(mac)))
+          {
+            strncat(priority, ":+", len - 1);
+            strncat(priority, p, len - 1);
+          }
+          if ((p= gnutls_kx_get_name(kx)))
+          {
+            strncat(priority, ":+", len - 1);
+            strncat(priority, p, len - 1);
+          }
           return priority;
         }
       }
@@ -1329,6 +1361,7 @@ int ma_tls_verify_server_cert(MARIADB_TLS *ctls __attribute__((unused)))
 
 const char *ma_tls_get_cipher(MARIADB_TLS *ctls)
 {
+#if GNUTLS_VERSION_NUMBER < 0x030704
   gnutls_kx_algorithm_t kx;
   gnutls_cipher_algorithm_t cipher;
   gnutls_mac_algorithm_t mac;
@@ -1340,6 +1373,24 @@ const char *ma_tls_get_cipher(MARIADB_TLS *ctls)
   cipher= gnutls_cipher_get((gnutls_session_t)ctls->ssl);
   kx= gnutls_kx_get((gnutls_session_t)ctls->ssl);
   return openssl_cipher_name(kx, cipher, mac);
+#else
+  const char *cs= gnutls_ciphersuite_get((gnutls_session_t)ctls->ssl);
+  int i=0;
+
+  while (tls_ciphers[i].iana_name)
+  {
+    if (!strcmp(tls_ciphers[i].gnutls_name, cs))
+    {
+      if (tls_ciphers[i].openssl_name)
+        return tls_ciphers[i].openssl_name;
+      if (tls_ciphers[i].gnutls_name)
+        return tls_ciphers[i].gnutls_name;
+      return tls_ciphers[i].iana_name;
+    }
+    i++;
+  }
+  return NULL;
+#endif
 }
 
 static int my_verify_callback(gnutls_session_t ssl)

unittest/libmariadb/connection.c

@@ -1966,7 +1966,42 @@ static int test_conc632(MYSQL *my __attribute__((unused)))
   return OK;
 }
 
+#if defined(HAVE_GNUTLS) || defined(HAVE_OPENSSL)
+static int test_conc748(MYSQL *my __attribute__((unused)))
+{
+  MYSQL *mysql;
+  int i;
+  const char *ciphers[3]= {"TLS_AES_128_GCM_SHA256", "TLS_AES_256_GCM_SHA384", "TLS_CHACHA20_POLY1305_SHA256"};
+
+  for (i=0; i < 3; i++)
+  {
+    const char *tls_version;
+    mysql= mysql_init(NULL);
+
+    mysql_ssl_set(mysql, NULL, NULL, NULL, NULL, NULL);
+    mysql_optionsv(mysql, MYSQL_OPT_SSL_CIPHER, ciphers[i]);
+
+    if (!my_test_connect(mysql, hostname, NULL,
+                               NULL, schema, port, socketname, 0))
+    {
+      diag("error: %s", mysql_error(mysql));
+      return FAIL;
+    }
+
+    FAIL_IF(strcmp(ciphers[i], mysql_get_ssl_cipher(mysql)), "Cipher mismatch");
+    mariadb_get_infov(mysql, MARIADB_CONNECTION_TLS_VERSION, &tls_version);
+    FAIL_IF(strcmp(tls_version, "TLSv1.3"), "TLS version mismatch");
+
+    mysql_close(mysql);
+  }
+  return OK;
+}
+#endif
+
 struct my_tests_st my_tests[] = {
+#if defined(HAVE_GNUTLS) || defined(HAVE_OPENSSL)
+  {"test_conc748", test_conc748, TEST_CONNECTION_NONE, 0, NULL, NULL},
+#endif
   {"test_conc632", test_conc632, TEST_CONNECTION_NONE, 0, NULL, NULL},
   {"test_conc490", test_conc490, TEST_CONNECTION_NONE, 0, NULL, NULL},
   {"test_gtid", test_gtid, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},