Squashed 'lib/mbedtls/external/mbedtls/' content from commit 2ca6c285a0dd

git-subtree-dir: lib/mbedtls/external/mbedtls
git-subtree-split: 2ca6c285a0dd3f33982dd57299012dacab1ff206

1 files changed, 804 insertions, 0 deletions

diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
new file mode 100644
index 00000000000..febb881c804
--- /dev/null
+++ b/programs/ssl/ssl_mail_client.c
@@ -0,0 +1,804 @@
+/*
+ *  SSL client for SMTP servers
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+/* Enable definition of gethostname() even when compiling with -std=c99. Must
+ * be set before mbedtls_config.h, which pulls in glibc's features.h indirectly.
+ * Harmless on other platforms. */
+
+#define _POSIX_C_SOURCE 200112L
+#define _XOPEN_SOURCE 600
+
+#include "mbedtls/build_info.h"
+
+#include "mbedtls/platform.h"
+
+#if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
+    !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
+    !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_RSA_C) ||         \
+    !defined(MBEDTLS_CTR_DRBG_C) || !defined(MBEDTLS_X509_CRT_PARSE_C) || \
+    !defined(MBEDTLS_FS_IO)
+int main(void)
+{
+    mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or "
+                   "MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_CLI_C and/or "
+                   "MBEDTLS_NET_C and/or MBEDTLS_RSA_C and/or "
+                   "MBEDTLS_CTR_DRBG_C and/or MBEDTLS_X509_CRT_PARSE_C "
+                   "not defined.\n");
+    mbedtls_exit(0);
+}
+#else
+
+#include "mbedtls/base64.h"
+#include "mbedtls/error.h"
+#include "mbedtls/net_sockets.h"
+#include "mbedtls/ssl.h"
+#include "mbedtls/entropy.h"
+#include "mbedtls/ctr_drbg.h"
+#include "test/certs.h"
+#include "mbedtls/x509.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#if !defined(_MSC_VER) || defined(EFIX64) || defined(EFI32)
+#include <unistd.h>
+#else
+#include <io.h>
+#endif
+
+#if defined(_WIN32) || defined(_WIN32_WCE)
+#include <winsock2.h>
+#include <windows.h>
+
+#if defined(_MSC_VER)
+#if defined(_WIN32_WCE)
+#pragma comment( lib, "ws2.lib" )
+#else
+#pragma comment( lib, "ws2_32.lib" )
+#endif
+#endif /* _MSC_VER */
+#endif
+
+#define DFL_SERVER_NAME         "localhost"
+#define DFL_SERVER_PORT         "465"
+#define DFL_USER_NAME           "user"
+#define DFL_USER_PWD            "password"
+#define DFL_MAIL_FROM           ""
+#define DFL_MAIL_TO             ""
+#define DFL_DEBUG_LEVEL         0
+#define DFL_CA_FILE             ""
+#define DFL_CRT_FILE            ""
+#define DFL_KEY_FILE            ""
+#define DFL_FORCE_CIPHER        0
+#define DFL_MODE                0
+#define DFL_AUTHENTICATION      0
+
+#define MODE_SSL_TLS            0
+#define MODE_STARTTLS           0
+
+#if defined(MBEDTLS_BASE64_C)
+#define USAGE_AUTH \
+    "    authentication=%%d   default: 0 (disabled)\n"          \
+    "    user_name=%%s        default: \"" DFL_USER_NAME "\"\n" \
+                                                         "    user_pwd=%%s         default: \"" \
+    DFL_USER_PWD "\"\n"
+#else
+#define USAGE_AUTH \
+    "    authentication options disabled. (Require MBEDTLS_BASE64_C)\n"
+#endif /* MBEDTLS_BASE64_C */
+
+#if defined(MBEDTLS_FS_IO)
+#define USAGE_IO \
+    "    ca_file=%%s          default: \"\" (pre-loaded)\n" \
+    "    crt_file=%%s         default: \"\" (pre-loaded)\n" \
+    "    key_file=%%s         default: \"\" (pre-loaded)\n"
+#else
+#define USAGE_IO \
+    "    No file operations available (MBEDTLS_FS_IO not defined)\n"
+#endif /* MBEDTLS_FS_IO */
+
+#define USAGE \
+    "\n usage: ssl_mail_client param=<>...\n"                 \
+    "\n acceptable parameters:\n"                             \
+    "    server_name=%%s      default: " DFL_SERVER_NAME "\n" \
+                                                         "    server_port=%%d      default: " \
+    DFL_SERVER_PORT "\n" \
+                    "    debug_level=%%d      default: 0 (disabled)\n"        \
+                    "    mode=%%d             default: 0 (SSL/TLS) (1 for STARTTLS)\n"  \
+    USAGE_AUTH                                                \
+    "    mail_from=%%s        default: \"\"\n"                \
+    "    mail_to=%%s          default: \"\"\n"                \
+    USAGE_IO                                                  \
+    "    force_ciphersuite=<name>    default: all enabled\n"  \
+    " acceptable ciphersuite names:\n"
+
+
+/*
+ * global options
+ */
+struct options {
+    const char *server_name;    /* hostname of the server (client only)     */
+    const char *server_port;    /* port on which the ssl service runs       */
+    int debug_level;            /* level of debugging                       */
+    int authentication;         /* if authentication is required            */
+    int mode;                   /* SSL/TLS (0) or STARTTLS (1)              */
+    const char *user_name;      /* username to use for authentication       */
+    const char *user_pwd;       /* password to use for authentication       */
+    const char *mail_from;      /* E-Mail address to use as sender          */
+    const char *mail_to;        /* E-Mail address to use as recipient       */
+    const char *ca_file;        /* the file with the CA certificate(s)      */
+    const char *crt_file;       /* the file with the client certificate     */
+    const char *key_file;       /* the file with the client key             */
+    int force_ciphersuite[2];   /* protocol/ciphersuite to use, or all      */
+} opt;
+
+static void my_debug(void *ctx, int level,
+                     const char *file, int line,
+                     const char *str)
+{
+    ((void) level);
+
+    mbedtls_fprintf((FILE *) ctx, "%s:%04d: %s", file, line, str);
+    fflush((FILE *) ctx);
+}
+
+static int do_handshake(mbedtls_ssl_context *ssl)
+{
+    int ret;
+    uint32_t flags;
+    unsigned char buf[1024];
+    memset(buf, 0, 1024);
+
+    /*
+     * 4. Handshake
+     */
+    mbedtls_printf("  . Performing the SSL/TLS handshake...");
+    fflush(stdout);
+
+    while ((ret = mbedtls_ssl_handshake(ssl)) != 0) {
+        if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+#if defined(MBEDTLS_ERROR_C)
+            mbedtls_strerror(ret, (char *) buf, 1024);
+#endif
+            mbedtls_printf(" failed\n  ! mbedtls_ssl_handshake returned %d: %s\n\n", ret, buf);
+            return -1;
+        }
+    }
+
+    mbedtls_printf(" ok\n    [ Ciphersuite is %s ]\n",
+                   mbedtls_ssl_get_ciphersuite(ssl));
+
+    /*
+     * 5. Verify the server certificate
+     */
+    mbedtls_printf("  . Verifying peer X.509 certificate...");
+
+    /* In real life, we probably want to bail out when ret != 0 */
+    if ((flags = mbedtls_ssl_get_verify_result(ssl)) != 0) {
+#if !defined(MBEDTLS_X509_REMOVE_INFO)
+        char vrfy_buf[512];
+#endif
+
+        mbedtls_printf(" failed\n");
+
+#if !defined(MBEDTLS_X509_REMOVE_INFO)
+        mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), "  ! ", flags);
+
+        mbedtls_printf("%s\n", vrfy_buf);
+#endif
+    } else {
+        mbedtls_printf(" ok\n");
+    }
+
+#if !defined(MBEDTLS_X509_REMOVE_INFO)
+    mbedtls_printf("  . Peer certificate information    ...\n");
+    mbedtls_x509_crt_info((char *) buf, sizeof(buf) - 1, "      ",
+                          mbedtls_ssl_get_peer_cert(ssl));
+    mbedtls_printf("%s\n", buf);
+#endif
+
+    return 0;
+}
+
+static int write_ssl_data(mbedtls_ssl_context *ssl, unsigned char *buf, size_t len)
+{
+    int ret;
+
+    mbedtls_printf("\n%s", buf);
+    while (len && (ret = mbedtls_ssl_write(ssl, buf, len)) <= 0) {
+        if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+            mbedtls_printf(" failed\n  ! mbedtls_ssl_write returned %d\n\n", ret);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int write_ssl_and_get_response(mbedtls_ssl_context *ssl, unsigned char *buf, size_t len)
+{
+    int ret;
+    unsigned char data[128];
+    char code[4];
+    size_t i, idx = 0;
+
+    mbedtls_printf("\n%s", buf);
+    while (len && (ret = mbedtls_ssl_write(ssl, buf, len)) <= 0) {
+        if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+            mbedtls_printf(" failed\n  ! mbedtls_ssl_write returned %d\n\n", ret);
+            return -1;
+        }
+    }
+
+    do {
+        len = sizeof(data) - 1;
+        memset(data, 0, sizeof(data));
+        ret = mbedtls_ssl_read(ssl, data, len);
+
+        if (ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
+            continue;
+        }
+
+        if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) {
+            return -1;
+        }
+
+        if (ret <= 0) {
+            mbedtls_printf("failed\n  ! mbedtls_ssl_read returned %d\n\n", ret);
+            return -1;
+        }
+
+        mbedtls_printf("\n%s", data);
+        len = ret;
+        for (i = 0; i < len; i++) {
+            if (data[i] != '\n') {
+                if (idx < 4) {
+                    code[idx++] = data[i];
+                }
+                continue;
+            }
+
+            if (idx == 4 && code[0] >= '0' && code[0] <= '9' && code[3] == ' ') {
+                code[3] = '\0';
+                return atoi(code);
+            }
+
+            idx = 0;
+        }
+    } while (1);
+}
+
+static int write_and_get_response(mbedtls_net_context *sock_fd, unsigned char *buf, size_t len)
+{
+    int ret;
+    unsigned char data[128];
+    char code[4];
+    size_t i, idx = 0;
+
+    mbedtls_printf("\n%s", buf);
+    if (len && (ret = mbedtls_net_send(sock_fd, buf, len)) <= 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_net_send returned %d\n\n", ret);
+        return -1;
+    }
+
+    do {
+        len = sizeof(data) - 1;
+        memset(data, 0, sizeof(data));
+        ret = mbedtls_net_recv(sock_fd, data, len);
+
+        if (ret <= 0) {
+            mbedtls_printf("failed\n  ! mbedtls_net_recv returned %d\n\n", ret);
+            return -1;
+        }
+
+        data[len] = '\0';
+        mbedtls_printf("\n%s", data);
+        len = ret;
+        for (i = 0; i < len; i++) {
+            if (data[i] != '\n') {
+                if (idx < 4) {
+                    code[idx++] = data[i];
+                }
+                continue;
+            }
+
+            if (idx == 4 && code[0] >= '0' && code[0] <= '9' && code[3] == ' ') {
+                code[3] = '\0';
+                return atoi(code);
+            }
+
+            idx = 0;
+        }
+    } while (1);
+}
+
+int main(int argc, char *argv[])
+{
+    int ret = 1, len;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
+    mbedtls_net_context server_fd;
+#if defined(MBEDTLS_BASE64_C)
+    unsigned char base[1024];
+    /* buf is used as the destination buffer for printing base with the format:
+     * "%s\r\n". Hence, the size of buf should be at least the size of base
+     * plus 2 bytes for the \r and \n characters.
+     */
+    unsigned char buf[sizeof(base) + 2];
+#else
+    unsigned char buf[1024];
+#endif
+    char hostname[32];
+    const char *pers = "ssl_mail_client";
+
+    mbedtls_entropy_context entropy;
+    mbedtls_ctr_drbg_context ctr_drbg;
+    mbedtls_ssl_context ssl;
+    mbedtls_ssl_config conf;
+    mbedtls_x509_crt cacert;
+    mbedtls_x509_crt clicert;
+    mbedtls_pk_context pkey;
+    int i;
+    size_t n;
+    char *p, *q;
+    const int *list;
+
+    /*
+     * Make sure memory references are valid in case we exit early.
+     */
+    mbedtls_net_init(&server_fd);
+    mbedtls_ssl_init(&ssl);
+    mbedtls_ssl_config_init(&conf);
+    memset(&buf, 0, sizeof(buf));
+    mbedtls_x509_crt_init(&cacert);
+    mbedtls_x509_crt_init(&clicert);
+    mbedtls_pk_init(&pkey);
+    mbedtls_ctr_drbg_init(&ctr_drbg);
+    mbedtls_entropy_init(&entropy);
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    psa_status_t status = psa_crypto_init();
+    if (status != PSA_SUCCESS) {
+        mbedtls_fprintf(stderr, "Failed to initialize PSA Crypto implementation: %d\n",
+                        (int) status);
+        goto exit;
+    }
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+    if (argc < 2) {
+usage:
+        mbedtls_printf(USAGE);
+
+        list = mbedtls_ssl_list_ciphersuites();
+        while (*list) {
+            mbedtls_printf("    %s\n", mbedtls_ssl_get_ciphersuite_name(*list));
+            list++;
+        }
+        mbedtls_printf("\n");
+        goto exit;
+    }
+
+    opt.server_name         = DFL_SERVER_NAME;
+    opt.server_port         = DFL_SERVER_PORT;
+    opt.debug_level         = DFL_DEBUG_LEVEL;
+    opt.authentication      = DFL_AUTHENTICATION;
+    opt.mode                = DFL_MODE;
+    opt.user_name           = DFL_USER_NAME;
+    opt.user_pwd            = DFL_USER_PWD;
+    opt.mail_from           = DFL_MAIL_FROM;
+    opt.mail_to             = DFL_MAIL_TO;
+    opt.ca_file             = DFL_CA_FILE;
+    opt.crt_file            = DFL_CRT_FILE;
+    opt.key_file            = DFL_KEY_FILE;
+    opt.force_ciphersuite[0] = DFL_FORCE_CIPHER;
+
+    for (i = 1; i < argc; i++) {
+        p = argv[i];
+        if ((q = strchr(p, '=')) == NULL) {
+            goto usage;
+        }
+        *q++ = '\0';
+
+        if (strcmp(p, "server_name") == 0) {
+            opt.server_name = q;
+        } else if (strcmp(p, "server_port") == 0) {
+            opt.server_port = q;
+        } else if (strcmp(p, "debug_level") == 0) {
+            opt.debug_level = atoi(q);
+            if (opt.debug_level < 0 || opt.debug_level > 65535) {
+                goto usage;
+            }
+        } else if (strcmp(p, "authentication") == 0) {
+            opt.authentication = atoi(q);
+            if (opt.authentication < 0 || opt.authentication > 1) {
+                goto usage;
+            }
+        } else if (strcmp(p, "mode") == 0) {
+            opt.mode = atoi(q);
+            if (opt.mode < 0 || opt.mode > 1) {
+                goto usage;
+            }
+        } else if (strcmp(p, "user_name") == 0) {
+            opt.user_name = q;
+        } else if (strcmp(p, "user_pwd") == 0) {
+            opt.user_pwd = q;
+        } else if (strcmp(p, "mail_from") == 0) {
+            opt.mail_from = q;
+        } else if (strcmp(p, "mail_to") == 0) {
+            opt.mail_to = q;
+        } else if (strcmp(p, "ca_file") == 0) {
+            opt.ca_file = q;
+        } else if (strcmp(p, "crt_file") == 0) {
+            opt.crt_file = q;
+        } else if (strcmp(p, "key_file") == 0) {
+            opt.key_file = q;
+        } else if (strcmp(p, "force_ciphersuite") == 0) {
+            opt.force_ciphersuite[0] = -1;
+
+            opt.force_ciphersuite[0] = mbedtls_ssl_get_ciphersuite_id(q);
+
+            if (opt.force_ciphersuite[0] <= 0) {
+                goto usage;
+            }
+
+            opt.force_ciphersuite[1] = 0;
+        } else {
+            goto usage;
+        }
+    }
+
+    /*
+     * 0. Initialize the RNG and the session data
+     */
+    mbedtls_printf("\n  . Seeding the random number generator...");
+    fflush(stdout);
+
+    if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
+                                     (const unsigned char *) pers,
+                                     strlen(pers))) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_ctr_drbg_seed returned %d\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    /*
+     * 1.1. Load the trusted CA
+     */
+    mbedtls_printf("  . Loading the CA root certificate ...");
+    fflush(stdout);
+
+#if defined(MBEDTLS_FS_IO)
+    if (strlen(opt.ca_file)) {
+        ret = mbedtls_x509_crt_parse_file(&cacert, opt.ca_file);
+    } else
+#endif
+#if defined(MBEDTLS_PEM_PARSE_C)
+    ret = mbedtls_x509_crt_parse(&cacert, (const unsigned char *) mbedtls_test_cas_pem,
+                                 mbedtls_test_cas_pem_len);
+#else
+    {
+        mbedtls_printf("MBEDTLS_PEM_PARSE_C not defined.");
+        goto exit;
+    }
+#endif
+    if (ret < 0) {
+        mbedtls_printf(" failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok (%d skipped)\n", ret);
+
+    /*
+     * 1.2. Load own certificate and private key
+     *
+     * (can be skipped if client authentication is not required)
+     */
+    mbedtls_printf("  . Loading the client cert. and key...");
+    fflush(stdout);
+
+#if defined(MBEDTLS_FS_IO)
+    if (strlen(opt.crt_file)) {
+        ret = mbedtls_x509_crt_parse_file(&clicert, opt.crt_file);
+    } else
+#endif
+    ret = mbedtls_x509_crt_parse(&clicert, (const unsigned char *) mbedtls_test_cli_crt,
+                                 mbedtls_test_cli_crt_len);
+    if (ret != 0) {
+        mbedtls_printf(" failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret);
+        goto exit;
+    }
+
+#if defined(MBEDTLS_FS_IO)
+    if (strlen(opt.key_file)) {
+        ret = mbedtls_pk_parse_keyfile(&pkey, opt.key_file, "",
+                                       mbedtls_ctr_drbg_random, &ctr_drbg);
+    } else
+#endif
+#if defined(MBEDTLS_PEM_PARSE_C)
+    {
+        ret = mbedtls_pk_parse_key(&pkey,
+                                   (const unsigned char *) mbedtls_test_cli_key,
+                                   mbedtls_test_cli_key_len,
+                                   NULL,
+                                   0,
+                                   mbedtls_ctr_drbg_random,
+                                   &ctr_drbg);
+    }
+#else
+    {
+        mbedtls_printf("MBEDTLS_PEM_PARSE_C not defined.");
+        goto exit;
+    }
+#endif
+    if (ret != 0) {
+        mbedtls_printf(" failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    /*
+     * 2. Start the connection
+     */
+    mbedtls_printf("  . Connecting to tcp/%s/%s...", opt.server_name,
+                   opt.server_port);
+    fflush(stdout);
+
+    if ((ret = mbedtls_net_connect(&server_fd, opt.server_name,
+                                   opt.server_port, MBEDTLS_NET_PROTO_TCP)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_net_connect returned %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    /*
+     * 3. Setup stuff
+     */
+    mbedtls_printf("  . Setting up the SSL/TLS structure...");
+    fflush(stdout);
+
+    if ((ret = mbedtls_ssl_config_defaults(&conf,
+                                           MBEDTLS_SSL_IS_CLIENT,
+                                           MBEDTLS_SSL_TRANSPORT_STREAM,
+                                           MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_ssl_config_defaults returned %d\n\n", ret);
+        goto exit;
+    }
+
+    /* OPTIONAL is not optimal for security,
+     * but makes interop easier in this simplified example */
+    mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
+
+    mbedtls_ssl_conf_rng(&conf, mbedtls_ctr_drbg_random, &ctr_drbg);
+    mbedtls_ssl_conf_dbg(&conf, my_debug, stdout);
+
+    if (opt.force_ciphersuite[0] != DFL_FORCE_CIPHER) {
+        mbedtls_ssl_conf_ciphersuites(&conf, opt.force_ciphersuite);
+    }
+
+    mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
+    if ((ret = mbedtls_ssl_conf_own_cert(&conf, &clicert, &pkey)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret);
+        goto exit;
+    }
+
+    if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_ssl_setup returned %d\n\n", ret);
+        goto exit;
+    }
+
+    if ((ret = mbedtls_ssl_set_hostname(&ssl, opt.server_name)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_ssl_set_bio(&ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, NULL);
+
+    mbedtls_printf(" ok\n");
+
+    if (opt.mode == MODE_SSL_TLS) {
+        if (do_handshake(&ssl) != 0) {
+            goto exit;
+        }
+
+        mbedtls_printf("  > Get header from server:");
+        fflush(stdout);
+
+        ret = write_ssl_and_get_response(&ssl, buf, 0);
+        if (ret < 200 || ret > 299) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+
+        mbedtls_printf("  > Write EHLO to server:");
+        fflush(stdout);
+
+        gethostname(hostname, 32);
+        len = sprintf((char *) buf, "EHLO %s\r\n", hostname);
+        ret = write_ssl_and_get_response(&ssl, buf, len);
+        if (ret < 200 || ret > 299) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+    } else {
+        mbedtls_printf("  > Get header from server:");
+        fflush(stdout);
+
+        ret = write_and_get_response(&server_fd, buf, 0);
+        if (ret < 200 || ret > 299) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+
+        mbedtls_printf("  > Write EHLO to server:");
+        fflush(stdout);
+
+        gethostname(hostname, 32);
+        len = sprintf((char *) buf, "EHLO %s\r\n", hostname);
+        ret = write_and_get_response(&server_fd, buf, len);
+        if (ret < 200 || ret > 299) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+
+        mbedtls_printf("  > Write STARTTLS to server:");
+        fflush(stdout);
+
+        gethostname(hostname, 32);
+        len = sprintf((char *) buf, "STARTTLS\r\n");
+        ret = write_and_get_response(&server_fd, buf, len);
+        if (ret < 200 || ret > 299) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+
+        if (do_handshake(&ssl) != 0) {
+            goto exit;
+        }
+    }
+
+#if defined(MBEDTLS_BASE64_C)
+    if (opt.authentication) {
+        mbedtls_printf("  > Write AUTH LOGIN to server:");
+        fflush(stdout);
+
+        len = sprintf((char *) buf, "AUTH LOGIN\r\n");
+        ret = write_ssl_and_get_response(&ssl, buf, len);
+        if (ret < 200 || ret > 399) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+
+        mbedtls_printf("  > Write username to server: %s", opt.user_name);
+        fflush(stdout);
+
+        ret = mbedtls_base64_encode(base, sizeof(base), &n, (const unsigned char *) opt.user_name,
+                                    strlen(opt.user_name));
+
+        if (ret != 0) {
+            mbedtls_printf(" failed\n  ! mbedtls_base64_encode returned %d\n\n", ret);
+            goto exit;
+        }
+        len = sprintf((char *) buf, "%s\r\n", base);
+        ret = write_ssl_and_get_response(&ssl, buf, len);
+        if (ret < 300 || ret > 399) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+
+        mbedtls_printf("  > Write password to server: %s", opt.user_pwd);
+        fflush(stdout);
+
+        ret = mbedtls_base64_encode(base, sizeof(base), &n, (const unsigned char *) opt.user_pwd,
+                                    strlen(opt.user_pwd));
+
+        if (ret != 0) {
+            mbedtls_printf(" failed\n  ! mbedtls_base64_encode returned %d\n\n", ret);
+            goto exit;
+        }
+        len = sprintf((char *) buf, "%s\r\n", base);
+        ret = write_ssl_and_get_response(&ssl, buf, len);
+        if (ret < 200 || ret > 399) {
+            mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+            goto exit;
+        }
+
+        mbedtls_printf(" ok\n");
+    }
+#endif
+
+    mbedtls_printf("  > Write MAIL FROM to server:");
+    fflush(stdout);
+
+    len = sprintf((char *) buf, "MAIL FROM:<%s>\r\n", opt.mail_from);
+    ret = write_ssl_and_get_response(&ssl, buf, len);
+    if (ret < 200 || ret > 299) {
+        mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    mbedtls_printf("  > Write RCPT TO to server:");
+    fflush(stdout);
+
+    len = sprintf((char *) buf, "RCPT TO:<%s>\r\n", opt.mail_to);
+    ret = write_ssl_and_get_response(&ssl, buf, len);
+    if (ret < 200 || ret > 299) {
+        mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    mbedtls_printf("  > Write DATA to server:");
+    fflush(stdout);
+
+    len = sprintf((char *) buf, "DATA\r\n");
+    ret = write_ssl_and_get_response(&ssl, buf, len);
+    if (ret < 300 || ret > 399) {
+        mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    mbedtls_printf("  > Write content to server:");
+    fflush(stdout);
+
+    len = sprintf((char *) buf, "From: %s\r\nSubject: Mbed TLS Test mail\r\n\r\n"
+                                "This is a simple test mail from the "
+                                "Mbed TLS mail client example.\r\n"
+                                "\r\n"
+                                "Enjoy!", opt.mail_from);
+    ret = write_ssl_data(&ssl, buf, len);
+
+    len = sprintf((char *) buf, "\r\n.\r\n");
+    ret = write_ssl_and_get_response(&ssl, buf, len);
+    if (ret < 200 || ret > 299) {
+        mbedtls_printf(" failed\n  ! server responded with %d\n\n", ret);
+        goto exit;
+    }
+
+    mbedtls_printf(" ok\n");
+
+    mbedtls_ssl_close_notify(&ssl);
+
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
+exit:
+
+    mbedtls_net_free(&server_fd);
+    mbedtls_x509_crt_free(&clicert);
+    mbedtls_x509_crt_free(&cacert);
+    mbedtls_pk_free(&pkey);
+    mbedtls_ssl_free(&ssl);
+    mbedtls_ssl_config_free(&conf);
+    mbedtls_ctr_drbg_free(&ctr_drbg);
+    mbedtls_entropy_free(&entropy);
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    mbedtls_psa_crypto_free();
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+    mbedtls_exit(exit_code);
+}
+#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
+          MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C **
+          MBEDTLS_CTR_DRBG_C */