wolfssl: add CURLOPT_TLS13_CIPHERS support

Bring setting ciphers with WolfSSL in line with other SSL backends,
to make the curl interface more consistent across the backends.

Now the tls1.3 ciphers are set with the --tls13-ciphers option, when
not set the default tls1.3 ciphers are used. The tls1.2 (1.1, 1.0)
ciphers are set with the --ciphers option, when not set the default
tls1.2 ciphers are used. The ciphers available for the connection
are now a union of the tls1.3 and tls1.2 ciphers.

This changes the behaviour for WolfSSL when --ciphers is set, but
--tls13-ciphers is not set. Now the ciphers set with --ciphers
are combined with the default tls1.3 ciphers, whereas before solely
the ciphers of --ciphers were used.

Thus before when no tls1.3 ciphers were specified in --ciphers,
tls1.3 was completely disabled. This might not be what the user
expected, especially as this does not happen with OpenSSL.

Closes #14385

lib/vtls/wolfssl.c

@@ -623,6 +623,36 @@ CURLcode Curl_wssl_setup_x509_store(struct Curl_cfilter *cf,
   return result;
 }
 
+#ifdef WOLFSSL_TLS13
+static size_t
+wssl_get_default_ciphers(bool tls13, char *buf, size_t size)
+{
+  size_t len = 0;
+  char *term = buf;
+  int i;
+  char *str;
+  size_t n;
+
+  for(i = 0; (str = wolfSSL_get_cipher_list(i)); i++) {
+    if((strncmp(str, "TLS13", 5) == 0) != tls13)
+      continue;
+
+    n = strlen(str);
+    if(buf && len + n + 1 <= size) {
+      memcpy(buf + len, str, n);
+      term = buf + len + n;
+      *term = ':';
+    }
+    len += n + 1;
+  }
+
+  if(buf)
+    *term = '\0';
+
+  return len > 0 ? len - 1 : 0;
+}
+#endif
+
 /*
  * This function loads all the client/CA certificates and CRLs. Setup the TLS
  * layer and do all necessary magic.
@@ -753,6 +783,7 @@ wolfssl_connect_step1(struct Curl_cfilter *cf, struct Curl_easy *data)
     break;
   }
 
+#ifndef WOLFSSL_TLS13
   ciphers = conn_config->cipher_list;
   if(ciphers) {
     if(!SSL_CTX_set_cipher_list(backend->ctx, ciphers)) {
@@ -761,6 +792,44 @@ wolfssl_connect_step1(struct Curl_cfilter *cf, struct Curl_easy *data)
     }
     infof(data, "Cipher selection: %s", ciphers);
   }
+#else
+  if(conn_config->cipher_list || conn_config->cipher_list13) {
+    const char *ciphers12 = conn_config->cipher_list;
+    const char *ciphers13 = conn_config->cipher_list13;
+
+    /* Set ciphers to a combination of ciphers_list and ciphers_list13.
+     * If cipher_list is not set use the default TLSv1.2 (1.1, 1.0) ciphers.
+     * If cipher_list13 is not set use the default TLSv1.3 ciphers. */
+    size_t len13 = ciphers13 ? strlen(ciphers13)
+        : wssl_get_default_ciphers(true, NULL, 0);
+    size_t len12 = ciphers12 ? strlen(ciphers12)
+        : wssl_get_default_ciphers(false, NULL, 0);
+
+    ciphers = malloc(len13 + 1 + len12 + 1);
+    if(!ciphers)
+      return CURLE_OUT_OF_MEMORY;
+
+    if(ciphers13)
+      memcpy(ciphers, ciphers13, len13);
+    else
+      wssl_get_default_ciphers(true, ciphers, len13 + 1);
+    ciphers[len13] = ':';
+
+    if(ciphers12)
+      memcpy(ciphers + len13 + 1, ciphers12, len12);
+    else
+      wssl_get_default_ciphers(false, ciphers + len13 + 1, len12 + 1);
+    ciphers[len13 + 1 + len12] = '\0';
+
+    if(!SSL_CTX_set_cipher_list(backend->ctx, ciphers)) {
+      failf(data, "failed setting cipher list: %s", ciphers);
+      free(ciphers);
+      return CURLE_SSL_CIPHER;
+    }
+    infof(data, "Cipher selection: %s", ciphers);
+    free(ciphers);
+  }
+#endif
 
   curves = conn_config->curves;
   if(curves) {
@@ -1846,6 +1915,9 @@ const struct Curl_ssl Curl_ssl_wolfssl = {
   SSLSUPP_ECH |
 #endif
   SSLSUPP_SSL_CTX |
+#ifdef WOLFSSL_TLS13
+  SSLSUPP_TLS13_CIPHERSUITES |
+#endif
   SSLSUPP_CA_CACHE,
 
   sizeof(struct wolfssl_ctx),

tests/http/test_17_ssl_use.py

@@ -215,8 +215,6 @@ class TestSSLUse:
                 pytest.skip('BoringSSL does not support setting TLSv1.3 ciphers')
             elif env.curl_uses_lib('mbedtls') and not env.curl_lib_version_at_least('mbedtls', '3.6.0'):
                 pytest.skip('mbedTLS TLSv1.3 support requires at least 3.6.0')
-            elif env.curl_uses_lib('wolfssl'):
-                extra_args = ['--ciphers', ':'.join(cipher_names)]
             else:
                 extra_args = ['--tls13-ciphers', ':'.join(cipher_names)]
         else: