HTTPS File Download Example for TLS Client on mbed OS

Diff: main.cpp

Revision:

0:fc70c47eecb4

Child:

9:1ac74f2d7bda

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Jul 27 14:34:24 2016 +0100
@@ -0,0 +1,472 @@
+/*
+ *  Hello world example of a TLS client: fetch an HTTPS page
+ *
+ *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+*/
+
+/** \file main.cpp
+ *  \brief An example TLS Client application
+ *  This application sends an HTTPS request to developer.mbed.org and searches for a string in
+ *  the result.
+ *
+ *  This example is implemented as a logic class (HelloHTTPS) wrapping a TCP socket.
+ *  The logic class handles all events, leaving the main loop to just check if the process
+ *  has finished.
+ */
+
+/* Change to a number between 1 and 4 to debug the TLS connection */
+#define DEBUG_LEVEL 0
+
+/* Change to 1 to skip certificate verification (UNSAFE, for debug only!) */
+#define UNSAFE 0
+
+#include "mbed.h"
+#include "NetworkStack.h"
+
+#include "EthernetInterface.h"
+#include "TCPSocket.h"
+
+#include "mbedtls/platform.h"
+#include "mbedtls/ssl.h"
+#include "mbedtls/entropy.h"
+#include "mbedtls/ctr_drbg.h"
+#include "mbedtls/error.h"
+#if DEBUG_LEVEL > 0
+#include "mbedtls/debug.h"
+#endif
+
+namespace {
+
+const char *HTTPS_SERVER_NAME = "developer.mbed.org";
+const int HTTPS_SERVER_PORT = 443;
+const int RECV_BUFFER_SIZE = 600;
+
+const char HTTPS_PATH[] = "/media/uploads/mbed_official/hello.txt";
+const size_t HTTPS_PATH_LEN = sizeof(HTTPS_PATH) - 1;
+
+/* Test related data */
+const char *HTTPS_OK_STR = "200 OK";
+const char *HTTPS_HELLO_STR = "Hello world!";
+
+/* personalization string for the drbg */
+const char *DRBG_PERS = "mbed TLS helloword client";
+
+/* List of trusted root CA certificates
+ * currently only GlobalSign, the CA for developer.mbed.org
+ *
+ * To add more than one root, just concatenate them.
+ */
+const char SSL_CA_PEM[] =
+/* GlobalSign Root certificate */
+"-----BEGIN CERTIFICATE-----\n"
+"MIIEaTCCA1GgAwIBAgILBAAAAAABRE7wQkcwDQYJKoZIhvcNAQELBQAwVzELMAkG\n"
+"A1UEBhMCQkUxGTAXBgNVBAoTEEdsb2JhbFNpZ24gbnYtc2ExEDAOBgNVBAsTB1Jv\n"
+"b3QgQ0ExGzAZBgNVBAMTEkdsb2JhbFNpZ24gUm9vdCBDQTAeFw0xNDAyMjAxMDAw\n"
+"MDBaFw0yNDAyMjAxMDAwMDBaMGYxCzAJBgNVBAYTAkJFMRkwFwYDVQQKExBHbG9i\n"
+"YWxTaWduIG52LXNhMTwwOgYDVQQDEzNHbG9iYWxTaWduIE9yZ2FuaXphdGlvbiBW\n"
+"YWxpZGF0aW9uIENBIC0gU0hBMjU2IC0gRzIwggEiMA0GCSqGSIb3DQEBAQUAA4IB\n"
+"DwAwggEKAoIBAQDHDmw/I5N/zHClnSDDDlM/fsBOwphJykfVI+8DNIV0yKMCLkZc\n"
+"C33JiJ1Pi/D4nGyMVTXbv/Kz6vvjVudKRtkTIso21ZvBqOOWQ5PyDLzm+ebomchj\n"
+"SHh/VzZpGhkdWtHUfcKc1H/hgBKueuqI6lfYygoKOhJJomIZeg0k9zfrtHOSewUj\n"
+"mxK1zusp36QUArkBpdSmnENkiN74fv7j9R7l/tyjqORmMdlMJekYuYlZCa7pnRxt\n"
+"Nw9KHjUgKOKv1CGLAcRFrW4rY6uSa2EKTSDtc7p8zv4WtdufgPDWi2zZCHlKT3hl\n"
+"2pK8vjX5s8T5J4BO/5ZS5gIg4Qdz6V0rvbLxAgMBAAGjggElMIIBITAOBgNVHQ8B\n"
+"Af8EBAMCAQYwEgYDVR0TAQH/BAgwBgEB/wIBADAdBgNVHQ4EFgQUlt5h8b0cFilT\n"
+"HMDMfTuDAEDmGnwwRwYDVR0gBEAwPjA8BgRVHSAAMDQwMgYIKwYBBQUHAgEWJmh0\n"
+"dHBzOi8vd3d3Lmdsb2JhbHNpZ24uY29tL3JlcG9zaXRvcnkvMDMGA1UdHwQsMCow\n"
+"KKAmoCSGImh0dHA6Ly9jcmwuZ2xvYmFsc2lnbi5uZXQvcm9vdC5jcmwwPQYIKwYB\n"
+"BQUHAQEEMTAvMC0GCCsGAQUFBzABhiFodHRwOi8vb2NzcC5nbG9iYWxzaWduLmNv\n"
+"bS9yb290cjEwHwYDVR0jBBgwFoAUYHtmGkUNl8qJUC99BM00qP/8/UswDQYJKoZI\n"
+"hvcNAQELBQADggEBAEYq7l69rgFgNzERhnF0tkZJyBAW/i9iIxerH4f4gu3K3w4s\n"
+"32R1juUYcqeMOovJrKV3UPfvnqTgoI8UV6MqX+x+bRDmuo2wCId2Dkyy2VG7EQLy\n"
+"XN0cvfNVlg/UBsD84iOKJHDTu/B5GqdhcIOKrwbFINihY9Bsrk8y1658GEV1BSl3\n"
+"30JAZGSGvip2CTFvHST0mdCF/vIhCPnG9vHQWe3WVjwIKANnuvD58ZAWR65n5ryA\n"
+"SOlCdjSXVWkkDoPWoC209fN5ikkodBpBocLTJIg1MGCUF7ThBCIxPTsvFwayuJ2G\n"
+"K1pp74P1S8SqtCr4fKGxhZSM9AyHDPSsQPhZSZg=\n"
+"-----END CERTIFICATE-----\n";
+
+#if OLD_CERTIFICATE
+/* GlobalSign Root R1 SHA1/RSA/2048
+ *   Serial no.  04 00 00 00 00 01 15 4b 5a c3 94 */
+"-----BEGIN CERTIFICATE-----\n"
+"MIIDdTCCAl2gAwIBAgILBAAAAAABFUtaw5QwDQYJKoZIhvcNAQEFBQAwVzELMAkG\n"
+"A1UEBhMCQkUxGTAXBgNVBAoTEEdsb2JhbFNpZ24gbnYtc2ExEDAOBgNVBAsTB1Jv\n"
+"b3QgQ0ExGzAZBgNVBAMTEkdsb2JhbFNpZ24gUm9vdCBDQTAeFw05ODA5MDExMjAw\n"
+"MDBaFw0yODAxMjgxMjAwMDBaMFcxCzAJBgNVBAYTAkJFMRkwFwYDVQQKExBHbG9i\n"
+"YWxTaWduIG52LXNhMRAwDgYDVQQLEwdSb290IENBMRswGQYDVQQDExJHbG9iYWxT\n"
+"aWduIFJvb3QgQ0EwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDaDuaZ\n"
+"jc6j40+Kfvvxi4Mla+pIH/EqsLmVEQS98GPR4mdmzxzdzxtIK+6NiY6arymAZavp\n"
+"xy0Sy6scTHAHoT0KMM0VjU/43dSMUBUc71DuxC73/OlS8pF94G3VNTCOXkNz8kHp\n"
+"1Wrjsok6Vjk4bwY8iGlbKk3Fp1S4bInMm/k8yuX9ifUSPJJ4ltbcdG6TRGHRjcdG\n"
+"snUOhugZitVtbNV4FpWi6cgKOOvyJBNPc1STE4U6G7weNLWLBYy5d4ux2x8gkasJ\n"
+"U26Qzns3dLlwR5EiUWMWea6xrkEmCMgZK9FGqkjWZCrXgzT/LCrBbBlDSgeF59N8\n"
+"9iFo7+ryUp9/k5DPAgMBAAGjQjBAMA4GA1UdDwEB/wQEAwIBBjAPBgNVHRMBAf8E\n"
+"BTADAQH/MB0GA1UdDgQWBBRge2YaRQ2XyolQL30EzTSo//z9SzANBgkqhkiG9w0B\n"
+"AQUFAAOCAQEA1nPnfE920I2/7LqivjTFKDK1fPxsnCwrvQmeU79rXqoRSLblCKOz\n"
+"yj1hTdNGCbM+w6DjY1Ub8rrvrTnhQ7k4o+YviiY776BQVvnGCv04zcQLcFGUl5gE\n"
+"38NflNUVyRRBnMRddWQVDf9VMOyGj/8N7yy5Y0b2qvzfvGn9LhJIZJrglfCm7ymP\n"
+"AbEVtQwdpf5pLGkkeB6zpxxxYu7KyJesF12KwvhHhm4qxFYxldBniYUr+WymXUad\n"
+"DKqC5JlR3XC321Y9YeRq4VzW9v493kHMB65jUr9TU/Qr6cf9tveCX4XSQRjbgbME\n"
+"HMUfpIBvFSDJ3gyICh3WZlXi/EjJKSZp4A==\n"
+"-----END CERTIFICATE-----\n";
+#endif
+}
+
+/**
+ * \brief HelloHTTPS implements the logic for fetching a file from a webserver
+ * using a TCP socket and parsing the result.
+ */
+class HelloHTTPS {
+public:
+    /**
+     * HelloHTTPS Constructor
+     * Initializes the TCP socket, sets up event handlers and flags.
+     *
+     * @param[in] domain The domain name to fetch from
+     * @param[in] port The port of the HTTPS server
+     */
+    HelloHTTPS(const char * domain, const uint16_t port, NetworkInterface *net_iface) :
+            _domain(domain), _port(port)
+    {
+
+        _error = false;
+        _gothello = false;
+        _got200 = false;
+        _bpos = 0;
+        _request_sent = 0;
+        _tcpsocket = new TCPSocket(net_iface);
+
+        mbedtls_entropy_init(&_entropy);
+        mbedtls_ctr_drbg_init(&_ctr_drbg);
+        mbedtls_x509_crt_init(&_cacert);
+        mbedtls_ssl_init(&_ssl);
+        mbedtls_ssl_config_init(&_ssl_conf);
+    }
+    /**
+     * HelloHTTPS Desctructor
+     */
+    ~HelloHTTPS() {
+        mbedtls_entropy_free(&_entropy);
+        mbedtls_ctr_drbg_free(&_ctr_drbg);
+        mbedtls_x509_crt_free(&_cacert);
+        mbedtls_ssl_free(&_ssl);
+        mbedtls_ssl_config_free(&_ssl_conf);
+    }
+    /**
+     * Start the test.
+     *
+     * Starts by clearing test flags, then resolves the address with DNS.
+     *
+     * @param[in] path The path of the file to fetch from the HTTPS server
+     * @return SOCKET_ERROR_NONE on success, or an error code on failure
+     */
+    void startTest(const char *path) {
+        /* Initialize the flags */
+        _got200 = false;
+        _gothello = false;
+        _error = false;
+        _disconnected = false;
+        _request_sent = false;
+        /* Fill the request buffer */
+        _bpos = snprintf(_buffer, sizeof(_buffer) - 1, "GET %s HTTP/1.1\nHost: %s\n\n", path, HTTPS_SERVER_NAME);
+
+        /*
+         * Initialize TLS-related stuf.
+         */
+        int ret;
+        if ((ret = mbedtls_ctr_drbg_seed(&_ctr_drbg, mbedtls_entropy_func, &_entropy,
+                          (const unsigned char *) DRBG_PERS,
+                          sizeof (DRBG_PERS))) != 0) {
+            print_mbedtls_error("mbedtls_crt_drbg_init", ret);
+            _error = true;
+            return;
+        }
+
+        if ((ret = mbedtls_x509_crt_parse(&_cacert, (const unsigned char *) SSL_CA_PEM,
+                           sizeof (SSL_CA_PEM))) != 0) {
+            print_mbedtls_error("mbedtls_x509_crt_parse", ret);
+            _error = true;
+            return;
+        }
+
+        if ((ret = mbedtls_ssl_config_defaults(&_ssl_conf,
+                        MBEDTLS_SSL_IS_CLIENT,
+                        MBEDTLS_SSL_TRANSPORT_STREAM,
+                        MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
+            print_mbedtls_error("mbedtls_ssl_config_defaults", ret);
+            _error = true;
+            return;
+        }
+
+        mbedtls_ssl_conf_ca_chain(&_ssl_conf, &_cacert, NULL);
+        mbedtls_ssl_conf_rng(&_ssl_conf, mbedtls_ctr_drbg_random, &_ctr_drbg);
+
+#if UNSAFE
+        mbedtls_ssl_conf_authmode(&_ssl_conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
+#endif
+
+#if DEBUG_LEVEL > 0
+        mbedtls_ssl_conf_verify(&_ssl_conf, my_verify, NULL);
+        mbedtls_ssl_conf_dbg(&_ssl_conf, my_debug, NULL);
+        mbedtls_debug_set_threshold(DEBUG_LEVEL);
+#endif
+
+        if ((ret = mbedtls_ssl_setup(&_ssl, &_ssl_conf)) != 0) {
+            print_mbedtls_error("mbedtls_ssl_setup", ret);
+            _error = true;
+            return;
+        }
+
+        mbedtls_ssl_set_hostname(&_ssl, HTTPS_SERVER_NAME);
+
+        mbedtls_ssl_set_bio(&_ssl, static_cast<void *>(_tcpsocket),
+                                   ssl_send, ssl_recv, NULL );
+
+
+        /* Connect to the server */
+        mbedtls_printf("Connecting with %s\r\n", _domain);
+        _tcpsocket->connect( _domain, _port );
+
+       /* Start the handshake, the rest will be done in onReceive() */
+        mbedtls_printf("Starting the TLS handshake...\r\n");
+        ret = mbedtls_ssl_handshake(&_ssl);
+        if (ret < 0) {
+            if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
+                ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+                print_mbedtls_error("mbedtls_ssl_handshake", ret);
+                onError(_tcpsocket, -1 );
+            }
+            return;
+        }
+
+        ret = mbedtls_ssl_write(&_ssl, (const unsigned char *) _buffer, _bpos);
+        if (ret < 0) {
+            if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
+                ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+                print_mbedtls_error("mbedtls_ssl_write", ret);
+                onError(_tcpsocket, -1 );
+            }
+            return;
+        }
+
+        /* It also means the handshake is done, time to print info */
+        printf("TLS connection to %s established\r\n", HTTPS_SERVER_NAME);
+
+        char buf[1024];
+        mbedtls_x509_crt_info(buf, sizeof(buf), "\r    ",
+                        mbedtls_ssl_get_peer_cert(&_ssl));
+        mbedtls_printf("Server certificate:\r\n%s\r", buf);
+
+#if defined(UNSAFE)
+        uint32_t flags = mbedtls_ssl_get_verify_result(&_ssl);
+        if( flags != 0 )
+        {
+            mbedtls_x509_crt_verify_info(buf, sizeof (buf), "\r  ! ", flags);
+            printf("Certificate verification failed:\r\n%s\r\r\n", buf);
+        }
+        else
+#endif
+            printf("Certificate verification passed\r\n\r\n");
+
+
+        /* Read data out of the socket */
+        ret = mbedtls_ssl_read(&_ssl, (unsigned char *) _buffer, sizeof(_buffer));
+        if (ret < 0) {
+            if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+                print_mbedtls_error("mbedtls_ssl_read", ret);
+                onError(_tcpsocket, -1 );
+            }
+            return;
+        }
+        _bpos = static_cast<size_t>(ret);
+
+        _buffer[_bpos] = 0;
+
+        /* Check each of the flags */
+        _got200 = _got200 || strstr(_buffer, HTTPS_OK_STR) != NULL;
+        _gothello = _gothello || strstr(_buffer, HTTPS_HELLO_STR) != NULL;
+
+        /* Print status messages */
+        mbedtls_printf("HTTPS: Received %d chars from server\r\n", _bpos);
+        mbedtls_printf("HTTPS: Received 200 OK status ... %s\r\n", _got200 ? "[OK]" : "[FAIL]");
+        mbedtls_printf("HTTPS: Received '%s' status ... %s\r\n", HTTPS_HELLO_STR, _gothello ? "[OK]" : "[FAIL]");
+        mbedtls_printf("HTTPS: Received message:\r\n\r\n");
+        mbedtls_printf("%s", _buffer);
+        _error = !(_got200 && _gothello);
+
+        _tcpsocket->close();
+    }
+    /**
+     * Check if the test has completed.
+     * @return Returns true if done, false otherwise.
+     */
+    bool done() {
+        return _error || (_got200 && _gothello);
+    }
+    /**
+     * Check if there was an error
+     * @return Returns true if there was an error, false otherwise.
+     */
+    bool error() {
+        return _error;
+    }
+    /**
+     * Closes the TCP socket
+     */
+    void close() {
+        _tcpsocket->close();
+        while (!_disconnected)
+            __WFI();
+    }
+protected:
+    /**
+     * Helper for pretty-printing mbed TLS error codes
+     */
+    static void print_mbedtls_error(const char *name, int err) {
+        char buf[128];
+        mbedtls_strerror(err, buf, sizeof (buf));
+        mbedtls_printf("%s() failed: -0x%04x (%d): %s\r\n", name, -err, err, buf);
+    }
+
+#if DEBUG_LEVEL > 0
+    /**
+     * Debug callback for mbed TLS
+     * Just prints on the USB serial port
+     */
+    static void my_debug(void *ctx, int level, const char *file, int line,
+                         const char *str)
+    {
+        const char *p, *basename;
+        (void) ctx;
+
+        /* Extract basename from file */
+        for(p = basename = file; *p != '\0'; p++) {
+            if(*p == '/' || *p == '\\') {
+                basename = p + 1;
+            }
+        }
+
+        mbedtls_printf("%s:%04d: |%d| %s", basename, line, level, str);
+    }
+
+    /**
+     * Certificate verification callback for mbed TLS
+     * Here we only use it to display information on each cert in the chain
+     */
+    static int my_verify(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags)
+    {
+        char buf[1024];
+        (void) data;
+
+        mbedtls_printf("\nVerifying certificate at depth %d:\n", depth);
+        mbedtls_x509_crt_info(buf, sizeof (buf) - 1, "  ", crt);
+        mbedtls_printf("%s", buf);
+
+        if (*flags == 0)
+            mbedtls_printf("No verification issue for this certificate\n");
+        else
+        {
+            mbedtls_x509_crt_verify_info(buf, sizeof (buf), "  ! ", *flags);
+            mbedtls_printf("%s\n", buf);
+        }
+
+        return 0;
+    }
+#endif
+
+    /**
+     * Receive callback for mbed TLS
+     */
+    static int ssl_recv(void *ctx, unsigned char *buf, size_t len) {
+        int recv = -1;
+        TCPSocket *socket = static_cast<TCPSocket *>(ctx);
+        recv = socket->recv(buf, len);
+
+        if(NSAPI_ERROR_WOULD_BLOCK == recv){
+            return MBEDTLS_ERR_SSL_WANT_READ;
+        }else if(recv < 0){
+            return -1;
+        }else{
+            return recv;
+        }
+   }
+
+    /**
+     * Send callback for mbed TLS
+     */
+    static int ssl_send(void *ctx, const unsigned char *buf, size_t len) {
+       int size = -1;
+        TCPSocket *socket = static_cast<TCPSocket *>(ctx);
+        size = socket->send(buf, len);
+
+        if(NSAPI_ERROR_WOULD_BLOCK == size){
+            return len;
+        }else if(size < 0){
+            return -1;
+        }else{
+            return size;
+        }
+    }
+
+    void onError(TCPSocket *s, int error) {
+        printf("MBED: Socket Error: %d\r\n", error);
+        s->close();
+        _error = true;
+    }
+
+protected:
+    TCPSocket* _tcpsocket;
+
+    const char *_domain;            /**< The domain name of the HTTPS server */
+    const uint16_t _port;           /**< The HTTPS server port */
+    char _buffer[RECV_BUFFER_SIZE]; /**< The response buffer */
+    size_t _bpos;                   /**< The current offset in the response buffer */
+    volatile bool _got200;          /**< Status flag for HTTPS 200 */
+    volatile bool _gothello;        /**< Status flag for finding the test string */
+    volatile bool _error;           /**< Status flag for an error */
+    volatile bool _disconnected;
+    volatile bool _request_sent;
+
+    mbedtls_entropy_context _entropy;
+    mbedtls_ctr_drbg_context _ctr_drbg;
+    mbedtls_x509_crt _cacert;
+    mbedtls_ssl_context _ssl;
+    mbedtls_ssl_config _ssl_conf;
+};
+
+/**
+ * The main loop of the HTTPS Hello World test
+ */
+int main() {
+    /* The default 9600 bps is too slow to print full TLS debug info and could
+     * cause the other party to time out. */
+
+    /* Inititalise with DHCP, connect, and start up the stack */
+    EthernetInterface eth_iface;
+    eth_iface.connect();
+    mbedtls_printf("Using Ethernet LWIP\r\n");
+    const char *ip_addr = eth_iface.get_ip_address();
+    if (ip_addr) {
+        mbedtls_printf("Client IP Address is %s\r\n", ip_addr);
+    } else {
+        mbedtls_printf("No Client IP Address\r\n");
+    }
+
+    HelloHTTPS hello(HTTPS_SERVER_NAME, HTTPS_SERVER_PORT, &eth_iface);
+    hello.startTest(HTTPS_PATH);
+}