1 /*
2  *  SSL client for SMTP servers
3  *
4  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5  *  SPDX-License-Identifier: Apache-2.0
6  *
7  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
8  *  not use this file except in compliance with the License.
9  *  You may obtain a copy of the License at
10  *
11  *  http://www.apache.org/licenses/LICENSE-2.0
12  *
13  *  Unless required by applicable law or agreed to in writing, software
14  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  *  See the License for the specific language governing permissions and
17  *  limitations under the License.
18  *
19  *  This file is part of mbed TLS (https://tls.mbed.org)
20  */
21 
22 #if !defined(MBEDTLS_CONFIG_FILE)
23 #include "mbedtls/config.h"
24 #else
25 #include MBEDTLS_CONFIG_FILE
26 #endif
27 
28 #if defined(MBEDTLS_PLATFORM_C)
29 #include "mbedtls/platform.h"
30 #else
31 #include <stdio.h>
32 #include <stdlib.h>
33 #define mbedtls_time       time
34 #define mbedtls_time_t     time_t
35 #define mbedtls_fprintf    fprintf
36 #define mbedtls_printf     printf
37 #endif
38 
39 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
40     !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
41     !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_RSA_C) ||         \
42     !defined(MBEDTLS_CTR_DRBG_C) || !defined(MBEDTLS_X509_CRT_PARSE_C) || \
43     !defined(MBEDTLS_FS_IO)
main(void)44 int main( void )
45 {
46     mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or "
47            "MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_CLI_C and/or "
48            "MBEDTLS_NET_C and/or MBEDTLS_RSA_C and/or "
49            "MBEDTLS_CTR_DRBG_C and/or MBEDTLS_X509_CRT_PARSE_C "
50            "not defined.\n");
51     return( 0 );
52 }
53 #else
54 
55 #include "mbedtls/base64.h"
56 #include "mbedtls/error.h"
57 #include "mbedtls/net_sockets.h"
58 #include "mbedtls/ssl.h"
59 #include "mbedtls/entropy.h"
60 #include "mbedtls/ctr_drbg.h"
61 #include "mbedtls/certs.h"
62 #include "mbedtls/x509.h"
63 
64 #include <stdlib.h>
65 #include <string.h>
66 
67 #if !defined(_MSC_VER) || defined(EFIX64) || defined(EFI32)
68 #include <unistd.h>
69 #else
70 #include <io.h>
71 #endif
72 
73 #if defined(_WIN32) || defined(_WIN32_WCE)
74 #include <winsock2.h>
75 #include <windows.h>
76 
77 #if defined(_MSC_VER)
78 #if defined(_WIN32_WCE)
79 #pragma comment( lib, "ws2.lib" )
80 #else
81 #pragma comment( lib, "ws2_32.lib" )
82 #endif
83 #endif /* _MSC_VER */
84 #endif
85 
86 #define DFL_SERVER_NAME         "localhost"
87 #define DFL_SERVER_PORT         "465"
88 #define DFL_USER_NAME           "user"
89 #define DFL_USER_PWD            "password"
90 #define DFL_MAIL_FROM           ""
91 #define DFL_MAIL_TO             ""
92 #define DFL_DEBUG_LEVEL         0
93 #define DFL_CA_FILE             ""
94 #define DFL_CRT_FILE            ""
95 #define DFL_KEY_FILE            ""
96 #define DFL_FORCE_CIPHER        0
97 #define DFL_MODE                0
98 #define DFL_AUTHENTICATION      0
99 
100 #define MODE_SSL_TLS            0
101 #define MODE_STARTTLS           0
102 
103 #if defined(MBEDTLS_BASE64_C)
104 #define USAGE_AUTH \
105     "    authentication=%%d   default: 0 (disabled)\n"      \
106     "    user_name=%%s        default: \"user\"\n"          \
107     "    user_pwd=%%s         default: \"password\"\n"
108 #else
109 #define USAGE_AUTH \
110     "    authentication options disabled. (Require MBEDTLS_BASE64_C)\n"
111 #endif /* MBEDTLS_BASE64_C */
112 
113 #if defined(MBEDTLS_FS_IO)
114 #define USAGE_IO \
115     "    ca_file=%%s          default: \"\" (pre-loaded)\n" \
116     "    crt_file=%%s         default: \"\" (pre-loaded)\n" \
117     "    key_file=%%s         default: \"\" (pre-loaded)\n"
118 #else
119 #define USAGE_IO \
120     "    No file operations available (MBEDTLS_FS_IO not defined)\n"
121 #endif /* MBEDTLS_FS_IO */
122 
123 #define USAGE \
124     "\n usage: ssl_mail_client param=<>...\n"               \
125     "\n acceptable parameters:\n"                           \
126     "    server_name=%%s      default: localhost\n"         \
127     "    server_port=%%d      default: 4433\n"              \
128     "    debug_level=%%d      default: 0 (disabled)\n"      \
129     "    mode=%%d             default: 0 (SSL/TLS) (1 for STARTTLS)\n"  \
130     USAGE_AUTH                                              \
131     "    mail_from=%%s        default: \"\"\n"              \
132     "    mail_to=%%s          default: \"\"\n"              \
133     USAGE_IO                                                \
134     "    force_ciphersuite=<name>    default: all enabled\n"\
135     " acceptable ciphersuite names:\n"
136 
137 /*
138  * global options
139  */
140 struct options
141 {
142     const char *server_name;    /* hostname of the server (client only)     */
143     const char *server_port;    /* port on which the ssl service runs       */
144     int debug_level;            /* level of debugging                       */
145     int authentication;         /* if authentication is required            */
146     int mode;                   /* SSL/TLS (0) or STARTTLS (1)              */
147     const char *user_name;      /* username to use for authentication       */
148     const char *user_pwd;       /* password to use for authentication       */
149     const char *mail_from;      /* E-Mail address to use as sender          */
150     const char *mail_to;        /* E-Mail address to use as recipient       */
151     const char *ca_file;        /* the file with the CA certificate(s)      */
152     const char *crt_file;       /* the file with the client certificate     */
153     const char *key_file;       /* the file with the client key             */
154     int force_ciphersuite[2];   /* protocol/ciphersuite to use, or all      */
155 } opt;
156 
my_debug(void * ctx,int level,const char * file,int line,const char * str)157 static void my_debug( void *ctx, int level,
158                       const char *file, int line,
159                       const char *str )
160 {
161     ((void) level);
162 
163     mbedtls_fprintf( (FILE *) ctx, "%s:%04d: %s", file, line, str );
164     fflush(  (FILE *) ctx  );
165 }
166 
do_handshake(mbedtls_ssl_context * ssl)167 static int do_handshake( mbedtls_ssl_context *ssl )
168 {
169     int ret;
170     uint32_t flags;
171     unsigned char buf[1024];
172     memset(buf, 0, 1024);
173 
174     /*
175      * 4. Handshake
176      */
177     mbedtls_printf( "  . Performing the SSL/TLS handshake..." );
178     fflush( stdout );
179 
180     while( ( ret = mbedtls_ssl_handshake( ssl ) ) != 0 )
181     {
182         if( ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE )
183         {
184 #if defined(MBEDTLS_ERROR_C)
185             mbedtls_strerror( ret, (char *) buf, 1024 );
186 #endif
187             mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned %d: %s\n\n", ret, buf );
188             return( -1 );
189         }
190     }
191 
192     mbedtls_printf( " ok\n    [ Ciphersuite is %s ]\n",
193             mbedtls_ssl_get_ciphersuite( ssl ) );
194 
195     /*
196      * 5. Verify the server certificate
197      */
198     mbedtls_printf( "  . Verifying peer X.509 certificate..." );
199 
200     /* In real life, we probably want to bail out when ret != 0 */
201     if( ( flags = mbedtls_ssl_get_verify_result( ssl ) ) != 0 )
202     {
203         char vrfy_buf[512];
204 
205         mbedtls_printf( " failed\n" );
206 
207         mbedtls_x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ), "  ! ", flags );
208 
209         mbedtls_printf( "%s\n", vrfy_buf );
210     }
211     else
212         mbedtls_printf( " ok\n" );
213 
214     mbedtls_printf( "  . Peer certificate information    ...\n" );
215     mbedtls_x509_crt_info( (char *) buf, sizeof( buf ) - 1, "      ",
216                    mbedtls_ssl_get_peer_cert( ssl ) );
217     mbedtls_printf( "%s\n", buf );
218 
219     return( 0 );
220 }
221 
write_ssl_data(mbedtls_ssl_context * ssl,unsigned char * buf,size_t len)222 static int write_ssl_data( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
223 {
224     int ret;
225 
226     mbedtls_printf("\n%s", buf);
227     while( len && ( ret = mbedtls_ssl_write( ssl, buf, len ) ) <= 0 )
228     {
229         if( ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE )
230         {
231             mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned %d\n\n", ret );
232             return -1;
233         }
234     }
235 
236     return( 0 );
237 }
238 
write_ssl_and_get_response(mbedtls_ssl_context * ssl,unsigned char * buf,size_t len)239 static int write_ssl_and_get_response( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
240 {
241     int ret;
242     unsigned char data[128];
243     char code[4];
244     size_t i, idx = 0;
245 
246     mbedtls_printf("\n%s", buf);
247     while( len && ( ret = mbedtls_ssl_write( ssl, buf, len ) ) <= 0 )
248     {
249         if( ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE )
250         {
251             mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned %d\n\n", ret );
252             return -1;
253         }
254     }
255 
256     do
257     {
258         len = sizeof( data ) - 1;
259         memset( data, 0, sizeof( data ) );
260         ret = mbedtls_ssl_read( ssl, data, len );
261 
262         if( ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE )
263             continue;
264 
265         if( ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY )
266             return -1;
267 
268         if( ret <= 0 )
269         {
270             mbedtls_printf( "failed\n  ! mbedtls_ssl_read returned %d\n\n", ret );
271             return -1;
272         }
273 
274         mbedtls_printf("\n%s", data);
275         len = ret;
276         for( i = 0; i < len; i++ )
277         {
278             if( data[i] != '\n' )
279             {
280                 if( idx < 4 )
281                     code[ idx++ ] = data[i];
282                 continue;
283             }
284 
285             if( idx == 4 && code[0] >= '0' && code[0] <= '9' && code[3] == ' ' )
286             {
287                 code[3] = '\0';
288                 return atoi( code );
289             }
290 
291             idx = 0;
292         }
293     }
294     while( 1 );
295 }
296 
write_and_get_response(mbedtls_net_context * sock_fd,unsigned char * buf,size_t len)297 static int write_and_get_response( mbedtls_net_context *sock_fd, unsigned char *buf, size_t len )
298 {
299     int ret;
300     unsigned char data[128];
301     char code[4];
302     size_t i, idx = 0;
303 
304     mbedtls_printf("\n%s", buf);
305     if( len && ( ret = mbedtls_net_send( sock_fd, buf, len ) ) <= 0 )
306     {
307         mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned %d\n\n", ret );
308             return -1;
309     }
310 
311     do
312     {
313         len = sizeof( data ) - 1;
314         memset( data, 0, sizeof( data ) );
315         ret = mbedtls_net_recv( sock_fd, data, len );
316 
317         if( ret <= 0 )
318         {
319             mbedtls_printf( "failed\n  ! read returned %d\n\n", ret );
320             return -1;
321         }
322 
323         data[len] = '\0';
324         mbedtls_printf("\n%s", data);
325         len = ret;
326         for( i = 0; i < len; i++ )
327         {
328             if( data[i] != '\n' )
329             {
330                 if( idx < 4 )
331                     code[ idx++ ] = data[i];
332                 continue;
333             }
334 
335             if( idx == 4 && code[0] >= '0' && code[0] <= '9' && code[3] == ' ' )
336             {
337                 code[3] = '\0';
338                 return atoi( code );
339             }
340 
341             idx = 0;
342         }
343     }
344     while( 1 );
345 }
346 
main(int argc,char * argv[])347 int main( int argc, char *argv[] )
348 {
349     int ret = 0, len;
350     mbedtls_net_context server_fd;
351     unsigned char buf[1024];
352 #if defined(MBEDTLS_BASE64_C)
353     unsigned char base[1024];
354 #endif
355     char hostname[32];
356     const char *pers = "ssl_mail_client";
357 
358     mbedtls_entropy_context entropy;
359     mbedtls_ctr_drbg_context ctr_drbg;
360     mbedtls_ssl_context ssl;
361     mbedtls_ssl_config conf;
362     mbedtls_x509_crt cacert;
363     mbedtls_x509_crt clicert;
364     mbedtls_pk_context pkey;
365     int i;
366     size_t n;
367     char *p, *q;
368     const int *list;
369 
370     /*
371      * Make sure memory references are valid in case we exit early.
372      */
373     mbedtls_net_init( &server_fd );
374     mbedtls_ssl_init( &ssl );
375     mbedtls_ssl_config_init( &conf );
376     memset( &buf, 0, sizeof( buf ) );
377     mbedtls_x509_crt_init( &cacert );
378     mbedtls_x509_crt_init( &clicert );
379     mbedtls_pk_init( &pkey );
380     mbedtls_ctr_drbg_init( &ctr_drbg );
381 
382     if( argc == 0 )
383     {
384     usage:
385         mbedtls_printf( USAGE );
386 
387         list = mbedtls_ssl_list_ciphersuites();
388         while( *list )
389         {
390             mbedtls_printf("    %s\n", mbedtls_ssl_get_ciphersuite_name( *list ) );
391             list++;
392         }
393         mbedtls_printf("\n");
394         goto exit;
395     }
396 
397     opt.server_name         = DFL_SERVER_NAME;
398     opt.server_port         = DFL_SERVER_PORT;
399     opt.debug_level         = DFL_DEBUG_LEVEL;
400     opt.authentication      = DFL_AUTHENTICATION;
401     opt.mode                = DFL_MODE;
402     opt.user_name           = DFL_USER_NAME;
403     opt.user_pwd            = DFL_USER_PWD;
404     opt.mail_from           = DFL_MAIL_FROM;
405     opt.mail_to             = DFL_MAIL_TO;
406     opt.ca_file             = DFL_CA_FILE;
407     opt.crt_file            = DFL_CRT_FILE;
408     opt.key_file            = DFL_KEY_FILE;
409     opt.force_ciphersuite[0]= DFL_FORCE_CIPHER;
410 
411     for( i = 1; i < argc; i++ )
412     {
413         p = argv[i];
414         if( ( q = strchr( p, '=' ) ) == NULL )
415             goto usage;
416         *q++ = '\0';
417 
418         if( strcmp( p, "server_name" ) == 0 )
419             opt.server_name = q;
420         else if( strcmp( p, "server_port" ) == 0 )
421             opt.server_port = q;
422         else if( strcmp( p, "debug_level" ) == 0 )
423         {
424             opt.debug_level = atoi( q );
425             if( opt.debug_level < 0 || opt.debug_level > 65535 )
426                 goto usage;
427         }
428         else if( strcmp( p, "authentication" ) == 0 )
429         {
430             opt.authentication = atoi( q );
431             if( opt.authentication < 0 || opt.authentication > 1 )
432                 goto usage;
433         }
434         else if( strcmp( p, "mode" ) == 0 )
435         {
436             opt.mode = atoi( q );
437             if( opt.mode < 0 || opt.mode > 1 )
438                 goto usage;
439         }
440         else if( strcmp( p, "user_name" ) == 0 )
441             opt.user_name = q;
442         else if( strcmp( p, "user_pwd" ) == 0 )
443             opt.user_pwd = q;
444         else if( strcmp( p, "mail_from" ) == 0 )
445             opt.mail_from = q;
446         else if( strcmp( p, "mail_to" ) == 0 )
447             opt.mail_to = q;
448         else if( strcmp( p, "ca_file" ) == 0 )
449             opt.ca_file = q;
450         else if( strcmp( p, "crt_file" ) == 0 )
451             opt.crt_file = q;
452         else if( strcmp( p, "key_file" ) == 0 )
453             opt.key_file = q;
454         else if( strcmp( p, "force_ciphersuite" ) == 0 )
455         {
456             opt.force_ciphersuite[0] = -1;
457 
458             opt.force_ciphersuite[0] = mbedtls_ssl_get_ciphersuite_id( q );
459 
460             if( opt.force_ciphersuite[0] <= 0 )
461                 goto usage;
462 
463             opt.force_ciphersuite[1] = 0;
464         }
465         else
466             goto usage;
467     }
468 
469     /*
470      * 0. Initialize the RNG and the session data
471      */
472     mbedtls_printf( "\n  . Seeding the random number generator..." );
473     fflush( stdout );
474 
475     mbedtls_entropy_init( &entropy );
476     if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
477                                (const unsigned char *) pers,
478                                strlen( pers ) ) ) != 0 )
479     {
480         mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n", ret );
481         goto exit;
482     }
483 
484     mbedtls_printf( " ok\n" );
485 
486     /*
487      * 1.1. Load the trusted CA
488      */
489     mbedtls_printf( "  . Loading the CA root certificate ..." );
490     fflush( stdout );
491 
492 #if defined(MBEDTLS_FS_IO)
493     if( strlen( opt.ca_file ) )
494         ret = mbedtls_x509_crt_parse_file( &cacert, opt.ca_file );
495     else
496 #endif
497 #if defined(MBEDTLS_CERTS_C)
498         ret = mbedtls_x509_crt_parse( &cacert, (const unsigned char *) mbedtls_test_cas_pem,
499                               mbedtls_test_cas_pem_len );
500 #else
501     {
502         ret = 1;
503         mbedtls_printf("MBEDTLS_CERTS_C not defined.");
504     }
505 #endif
506     if( ret < 0 )
507     {
508         mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret );
509         goto exit;
510     }
511 
512     mbedtls_printf( " ok (%d skipped)\n", ret );
513 
514     /*
515      * 1.2. Load own certificate and private key
516      *
517      * (can be skipped if client authentication is not required)
518      */
519     mbedtls_printf( "  . Loading the client cert. and key..." );
520     fflush( stdout );
521 
522 #if defined(MBEDTLS_FS_IO)
523     if( strlen( opt.crt_file ) )
524         ret = mbedtls_x509_crt_parse_file( &clicert, opt.crt_file );
525     else
526 #endif
527 #if defined(MBEDTLS_CERTS_C)
528         ret = mbedtls_x509_crt_parse( &clicert, (const unsigned char *) mbedtls_test_cli_crt,
529                               mbedtls_test_cli_crt_len );
530 #else
531     {
532         ret = -1;
533         mbedtls_printf("MBEDTLS_CERTS_C not defined.");
534     }
535 #endif
536     if( ret != 0 )
537     {
538         mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret );
539         goto exit;
540     }
541 
542 #if defined(MBEDTLS_FS_IO)
543     if( strlen( opt.key_file ) )
544         ret = mbedtls_pk_parse_keyfile( &pkey, opt.key_file, "" );
545     else
546 #endif
547 #if defined(MBEDTLS_CERTS_C) && defined(MBEDTLS_PEM_PARSE_C)
548         ret = mbedtls_pk_parse_key( &pkey, (const unsigned char *) mbedtls_test_cli_key,
549                 mbedtls_test_cli_key_len, NULL, 0 );
550 #else
551     {
552         ret = -1;
553         mbedtls_printf("MBEDTLS_CERTS_C or MBEDTLS_PEM_PARSE_C not defined.");
554     }
555 #endif
556     if( ret != 0 )
557     {
558         mbedtls_printf( " failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret );
559         goto exit;
560     }
561 
562     mbedtls_printf( " ok\n" );
563 
564     /*
565      * 2. Start the connection
566      */
567     mbedtls_printf( "  . Connecting to tcp/%s/%s...", opt.server_name,
568                                                 opt.server_port );
569     fflush( stdout );
570 
571     if( ( ret = mbedtls_net_connect( &server_fd, opt.server_name,
572                              opt.server_port, MBEDTLS_NET_PROTO_TCP ) ) != 0 )
573     {
574         mbedtls_printf( " failed\n  ! mbedtls_net_connect returned %d\n\n", ret );
575         goto exit;
576     }
577 
578     mbedtls_printf( " ok\n" );
579 
580     /*
581      * 3. Setup stuff
582      */
583     mbedtls_printf( "  . Setting up the SSL/TLS structure..." );
584     fflush( stdout );
585 
586     if( ( ret = mbedtls_ssl_config_defaults( &conf,
587                     MBEDTLS_SSL_IS_CLIENT,
588                     MBEDTLS_SSL_TRANSPORT_STREAM,
589                     MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 )
590     {
591         mbedtls_printf( " failed\n  ! mbedtls_ssl_config_defaults returned %d\n\n", ret );
592         goto exit;
593     }
594 
595     /* OPTIONAL is not optimal for security,
596      * but makes interop easier in this simplified example */
597     mbedtls_ssl_conf_authmode( &conf, MBEDTLS_SSL_VERIFY_OPTIONAL );
598 
599     mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
600     mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );
601 
602     if( opt.force_ciphersuite[0] != DFL_FORCE_CIPHER )
603         mbedtls_ssl_conf_ciphersuites( &conf, opt.force_ciphersuite );
604 
605     mbedtls_ssl_conf_ca_chain( &conf, &cacert, NULL );
606     if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &clicert, &pkey ) ) != 0 )
607     {
608         mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret );
609         goto exit;
610     }
611 
612     if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
613     {
614         mbedtls_printf( " failed\n  ! mbedtls_ssl_setup returned %d\n\n", ret );
615         goto exit;
616     }
617 
618     if( ( ret = mbedtls_ssl_set_hostname( &ssl, opt.server_name ) ) != 0 )
619     {
620         mbedtls_printf( " failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret );
621         goto exit;
622     }
623 
624     mbedtls_ssl_set_bio( &ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, NULL );
625 
626     mbedtls_printf( " ok\n" );
627 
628     if( opt.mode == MODE_SSL_TLS )
629     {
630         if( do_handshake( &ssl ) != 0 )
631             goto exit;
632 
633         mbedtls_printf( "  > Get header from server:" );
634         fflush( stdout );
635 
636         ret = write_ssl_and_get_response( &ssl, buf, 0 );
637         if( ret < 200 || ret > 299 )
638         {
639             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
640             goto exit;
641         }
642 
643         mbedtls_printf(" ok\n" );
644 
645         mbedtls_printf( "  > Write EHLO to server:" );
646         fflush( stdout );
647 
648         gethostname( hostname, 32 );
649         len = sprintf( (char *) buf, "EHLO %s\r\n", hostname );
650         ret = write_ssl_and_get_response( &ssl, buf, len );
651         if( ret < 200 || ret > 299 )
652         {
653             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
654             goto exit;
655         }
656     }
657     else
658     {
659         mbedtls_printf( "  > Get header from server:" );
660         fflush( stdout );
661 
662         ret = write_and_get_response( &server_fd, buf, 0 );
663         if( ret < 200 || ret > 299 )
664         {
665             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
666             goto exit;
667         }
668 
669         mbedtls_printf(" ok\n" );
670 
671         mbedtls_printf( "  > Write EHLO to server:" );
672         fflush( stdout );
673 
674         gethostname( hostname, 32 );
675         len = sprintf( (char *) buf, "EHLO %s\r\n", hostname );
676         ret = write_and_get_response( &server_fd, buf, len );
677         if( ret < 200 || ret > 299 )
678         {
679             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
680             goto exit;
681         }
682 
683         mbedtls_printf(" ok\n" );
684 
685         mbedtls_printf( "  > Write STARTTLS to server:" );
686         fflush( stdout );
687 
688         gethostname( hostname, 32 );
689         len = sprintf( (char *) buf, "STARTTLS\r\n" );
690         ret = write_and_get_response( &server_fd, buf, len );
691         if( ret < 200 || ret > 299 )
692         {
693             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
694             goto exit;
695         }
696 
697         mbedtls_printf(" ok\n" );
698 
699         if( do_handshake( &ssl ) != 0 )
700             goto exit;
701     }
702 
703 #if defined(MBEDTLS_BASE64_C)
704     if( opt.authentication )
705     {
706         mbedtls_printf( "  > Write AUTH LOGIN to server:" );
707         fflush( stdout );
708 
709         len = sprintf( (char *) buf, "AUTH LOGIN\r\n" );
710         ret = write_ssl_and_get_response( &ssl, buf, len );
711         if( ret < 200 || ret > 399 )
712         {
713             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
714             goto exit;
715         }
716 
717         mbedtls_printf(" ok\n" );
718 
719         mbedtls_printf( "  > Write username to server: %s", opt.user_name );
720         fflush( stdout );
721 
722         ret = mbedtls_base64_encode( base, sizeof( base ), &n, (const unsigned char *) opt.user_name,
723                              strlen( opt.user_name ) );
724 
725         if( ret != 0 ) {
726             mbedtls_printf( " failed\n  ! mbedtls_base64_encode returned %d\n\n", ret );
727             goto exit;
728         }
729         len = sprintf( (char *) buf, "%s\r\n", base );
730         ret = write_ssl_and_get_response( &ssl, buf, len );
731         if( ret < 300 || ret > 399 )
732         {
733             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
734             goto exit;
735         }
736 
737         mbedtls_printf(" ok\n" );
738 
739         mbedtls_printf( "  > Write password to server: %s", opt.user_pwd );
740         fflush( stdout );
741 
742         ret = mbedtls_base64_encode( base, sizeof( base ), &n, (const unsigned char *) opt.user_pwd,
743                              strlen( opt.user_pwd ) );
744 
745         if( ret != 0 ) {
746             mbedtls_printf( " failed\n  ! mbedtls_base64_encode returned %d\n\n", ret );
747             goto exit;
748         }
749         len = sprintf( (char *) buf, "%s\r\n", base );
750         ret = write_ssl_and_get_response( &ssl, buf, len );
751         if( ret < 200 || ret > 399 )
752         {
753             mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
754             goto exit;
755         }
756 
757         mbedtls_printf(" ok\n" );
758     }
759 #endif
760 
761     mbedtls_printf( "  > Write MAIL FROM to server:" );
762     fflush( stdout );
763 
764     len = sprintf( (char *) buf, "MAIL FROM:<%s>\r\n", opt.mail_from );
765     ret = write_ssl_and_get_response( &ssl, buf, len );
766     if( ret < 200 || ret > 299 )
767     {
768         mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
769         goto exit;
770     }
771 
772     mbedtls_printf(" ok\n" );
773 
774     mbedtls_printf( "  > Write RCPT TO to server:" );
775     fflush( stdout );
776 
777     len = sprintf( (char *) buf, "RCPT TO:<%s>\r\n", opt.mail_to );
778     ret = write_ssl_and_get_response( &ssl, buf, len );
779     if( ret < 200 || ret > 299 )
780     {
781         mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
782         goto exit;
783     }
784 
785     mbedtls_printf(" ok\n" );
786 
787     mbedtls_printf( "  > Write DATA to server:" );
788     fflush( stdout );
789 
790     len = sprintf( (char *) buf, "DATA\r\n" );
791     ret = write_ssl_and_get_response( &ssl, buf, len );
792     if( ret < 300 || ret > 399 )
793     {
794         mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
795         goto exit;
796     }
797 
798     mbedtls_printf(" ok\n" );
799 
800     mbedtls_printf( "  > Write content to server:" );
801     fflush( stdout );
802 
803     len = sprintf( (char *) buf, "From: %s\r\nSubject: mbed TLS Test mail\r\n\r\n"
804             "This is a simple test mail from the "
805             "mbed TLS mail client example.\r\n"
806             "\r\n"
807             "Enjoy!", opt.mail_from );
808     ret = write_ssl_data( &ssl, buf, len );
809 
810     len = sprintf( (char *) buf, "\r\n.\r\n");
811     ret = write_ssl_and_get_response( &ssl, buf, len );
812     if( ret < 200 || ret > 299 )
813     {
814         mbedtls_printf( " failed\n  ! server responded with %d\n\n", ret );
815         goto exit;
816     }
817 
818     mbedtls_printf(" ok\n" );
819 
820     mbedtls_ssl_close_notify( &ssl );
821 
822 exit:
823 
824     mbedtls_net_free( &server_fd );
825     mbedtls_x509_crt_free( &clicert );
826     mbedtls_x509_crt_free( &cacert );
827     mbedtls_pk_free( &pkey );
828     mbedtls_ssl_free( &ssl );
829     mbedtls_ssl_config_free( &conf );
830     mbedtls_ctr_drbg_free( &ctr_drbg );
831     mbedtls_entropy_free( &entropy );
832 
833 #if defined(_WIN32)
834     mbedtls_printf( "  + Press Enter to exit this program.\n" );
835     fflush( stdout ); getchar();
836 #endif
837 
838     return( ret );
839 }
840 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
841           MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C **
842           MBEDTLS_CTR_DRBG_C */
843