wolfssl: Add ALPN support

configure.ac

@@ -2206,7 +2206,8 @@ if test "$curl_ssl_msg" = "$init_ssl_msg"; then
         dnl Recent WolfSSL versions build without SSLv3 by default
         dnl WolfSSL needs configure --enable-opensslextra to have *get_peer*
         AC_CHECK_FUNCS(wolfSSLv3_client_method \
-                       wolfSSL_get_peer_certificate)
+                       wolfSSL_get_peer_certificate \
+                       wolfSSL_UseALPN)
       else
         dnl Cyassl needs configure --enable-opensslextra to have *get_peer*
         AC_CHECK_FUNCS(CyaSSL_get_peer_certificate)

docs/HTTP2.md

@@ -7,7 +7,8 @@ HTTP/2 with curl
 Build prerequisites
 -------------------
   - nghttp2
-  - OpenSSL, NSS, GnutTLS, PolarSSL or SChannel with a new enough version
+  - OpenSSL, NSS, GnutTLS, PolarSSL, wolfSSL or SChannel with a new enough
+    version.
 
 [nghttp2](https://nghttp2.org/)
 -------------------------------
@@ -59,6 +60,7 @@ provide the necessary TLS features. Right now we support:
   - GnuTLS:   ALPN
   - PolarSSL: ALPN
   - SChannel: ALPN
+  - wolfSSL:  ALPN
 
 Multiplexing
 ------------

lib/vtls/cyassl.c

@@ -77,6 +77,41 @@ and that's a problem since options.h hasn't been included yet. */
 #define CYASSL_MAX_ERROR_SZ 80
 #endif
 
+/* To determine what functions are available we rely on one or both of:
+   - the user's options.h generated by CyaSSL/wolfSSL
+   - the symbols detected by curl's configure
+   Since they are markedly different from one another, and one or the other may
+   not be available, we do some checking below to bring things in sync. */
+
+/* HAVE_ALPN is wolfSSL's build time symbol for enabling ALPN in options.h. */
+#ifndef HAVE_ALPN
+#ifdef HAVE_WOLFSSL_USEALPN
+#define HAVE_ALPN
+#endif
+#endif
+
+/* WOLFSSL_ALLOW_SSLV3 is wolfSSL's build time symbol for enabling SSLv3 in
+   options.h, but is only seen in >= 3.6.6 since that's when they started
+   disabling SSLv3 by default. */
+#ifndef WOLFSSL_ALLOW_SSLV3
+#if (LIBCYASSL_VERSION_HEX < 0x03006006) || \
+    defined(HAVE_WOLFSSLV3_CLIENT_METHOD)
+#define WOLFSSL_ALLOW_SSLV3
+#endif
+#endif
+
+/* KEEP_PEER_CERT is a product of the presence of build time symbol
+   OPENSSL_EXTRA without NO_CERTS, depending on the version. KEEP_PEER_CERT is
+   in wolfSSL's settings.h, and the latter two are build time symbols in
+   options.h. */
+#ifndef KEEP_PEER_CERT
+#if defined(HAVE_CYASSL_GET_PEER_CERTIFICATE) || \
+    defined(HAVE_WOLFSSL_GET_PEER_CERTIFICATE) || \
+    (defined(OPENSSL_EXTRA) && !defined(NO_CERTS))
+#define KEEP_PEER_CERT
+#endif
+#endif
+
 static Curl_recv cyassl_recv;
 static Curl_send cyassl_send;
 
@@ -143,9 +178,7 @@ cyassl_connect_step1(struct connectdata *conn,
     use_sni(TRUE);
     break;
   case CURL_SSLVERSION_SSLv3:
-    /* before WolfSSL SSLv3 was enabled by default, and starting in WolfSSL
-       we check for its presence since it is built without it by default */
-#if !defined(WOLFSSL_VERSION) || defined(HAVE_WOLFSSLV3_CLIENT_METHOD)
+#ifdef WOLFSSL_ALLOW_SSLV3
     req_method = SSLv3_client_method();
     use_sni(FALSE);
 #else
@@ -309,6 +342,33 @@ cyassl_connect_step1(struct connectdata *conn,
     return CURLE_OUT_OF_MEMORY;
   }
 
+#ifdef HAVE_ALPN
+  if(data->set.ssl_enable_alpn) {
+    char protocols[128];
+    *protocols = '\0';
+
+    /* wolfSSL's ALPN protocol name list format is a comma separated string of
+       protocols in descending order of preference, eg: "h2,http/1.1" */
+
+#ifdef USE_NGHTTP2
+    if(data->set.httpversion >= CURL_HTTP_VERSION_2) {
+      strcpy(protocols + strlen(protocols), NGHTTP2_PROTO_VERSION_ID ",");
+      infof(data, "ALPN, offering %s\n", NGHTTP2_PROTO_VERSION_ID);
+    }
+#endif
+
+    strcpy(protocols + strlen(protocols), ALPN_HTTP_1_1);
+    infof(data, "ALPN, offering %s\n", ALPN_HTTP_1_1);
+
+    if(wolfSSL_UseALPN(conssl->handle, protocols,
+                       (unsigned)strlen(protocols),
+                       WOLFSSL_ALPN_CONTINUE_ON_MISMATCH) != SSL_SUCCESS) {
+      failf(data, "SSL: failed setting ALPN protocols");
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+  }
+#endif /* HAVE_ALPN */
+
   /* Check if there's a cached ID we can/should use here! */
   if(!Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL)) {
     /* we got a session id, use it! */
@@ -413,8 +473,7 @@ cyassl_connect_step2(struct connectdata *conn,
   }
 
   if(data->set.str[STRING_SSL_PINNEDPUBLICKEY]) {
-#if defined(HAVE_WOLFSSL_GET_PEER_CERTIFICATE) ||       \
-  defined(HAVE_CYASSL_GET_PEER_CERTIFICATE)
+#ifdef KEEP_PEER_CERT
     X509 *x509;
     const char *x509_der;
     int x509_der_len;
@@ -457,6 +516,41 @@ cyassl_connect_step2(struct connectdata *conn,
 #endif
   }
 
+#ifdef HAVE_ALPN
+  if(data->set.ssl_enable_alpn) {
+    int rc;
+    char *protocol = NULL;
+    unsigned short protocol_len = 0;
+
+    rc = wolfSSL_ALPN_GetProtocol(conssl->handle, &protocol, &protocol_len);
+
+    if(rc == SSL_SUCCESS) {
+      infof(data, "ALPN, server accepted to use %.*s\n", protocol_len,
+            protocol);
+
+      if(protocol_len == ALPN_HTTP_1_1_LENGTH &&
+         !memcmp(protocol, ALPN_HTTP_1_1, ALPN_HTTP_1_1_LENGTH))
+        conn->negnpn = CURL_HTTP_VERSION_1_1;
+#ifdef USE_NGHTTP2
+      else if(data->set.httpversion >= CURL_HTTP_VERSION_2 &&
+              protocol_len == NGHTTP2_PROTO_VERSION_ID_LEN &&
+              !memcmp(protocol, NGHTTP2_PROTO_VERSION_ID,
+                      NGHTTP2_PROTO_VERSION_ID_LEN))
+        conn->negnpn = CURL_HTTP_VERSION_2;
+#endif
+      else
+        infof(data, "ALPN, unrecognized protocol %.*s\n", protocol_len,
+              protocol);
+    }
+    else if(rc == SSL_ALPN_NOT_FOUND)
+      infof(data, "ALPN, server did not agree to a protocol\n");
+    else {
+      failf(data, "ALPN, failure getting protocol, error %d", rc);
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+  }
+#endif /* HAVE_ALPN */
+
   conssl->connecting_state = ssl_connect_3;
   infof(data, "SSL connected\n");
 

projects/wolfssl_options.h

@@ -19,6 +19,7 @@ These configure flags were used in MinGW to generate the options in this file:
 --enable-sessioncerts
 --enable-certgen
 --enable-testcert
+--enable-alpn
 C_EXTRA_FLAGS="-DFP_MAX_BITS=16384 -DTFM_TIMING_RESISTANT"
 
 Two generated options HAVE_THREAD_LS and _POSIX_THREADS were removed since they
@@ -129,6 +130,8 @@ extern "C" {
 #undef  USE_FAST_MATH
 #define USE_FAST_MATH
 
+#undef  HAVE_ALPN
+#define HAVE_ALPN
 
 #ifdef __cplusplus
 }