1 /*
2 * Copyright 2013-2025 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /*
11 * A minimal program to serve an SSL connection. It uses blocking. It uses
12 * the SSL_CONF API with a configuration file. cc -I../../include saccept.c
13 * -L../.. -lssl -lcrypto -ldl
14 */
15
16 #include <stdio.h>
17 #include <string.h>
18 #include <signal.h>
19 #include <stdlib.h>
20 #include <openssl/err.h>
21 #include <openssl/ssl.h>
22 #include <openssl/conf.h>
23
main(int argc,char * argv[])24 int main(int argc, char *argv[])
25 {
26 char *port = "*:4433";
27 BIO *in = NULL;
28 BIO *ssl_bio = NULL;
29 BIO *tmp;
30 SSL_CTX *ctx;
31 SSL_CONF_CTX *cctx = NULL;
32 CONF *conf = NULL;
33 STACK_OF(CONF_VALUE) *sect = NULL;
34 CONF_VALUE *cnf;
35 long errline = -1;
36 char buf[512];
37 int ret = EXIT_FAILURE, i;
38
39 ctx = SSL_CTX_new(TLS_server_method());
40
41 conf = NCONF_new(NULL);
42
43 if (NCONF_load(conf, "accept.cnf", &errline) <= 0) {
44 if (errline <= 0)
45 fprintf(stderr, "Error processing config file\n");
46 else
47 fprintf(stderr, "Error on line %ld\n", errline);
48 goto err;
49 }
50
51 sect = NCONF_get_section(conf, "default");
52
53 if (sect == NULL) {
54 fprintf(stderr, "Error retrieving default section\n");
55 goto err;
56 }
57
58 cctx = SSL_CONF_CTX_new();
59 SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_SERVER);
60 SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_CERTIFICATE);
61 SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_FILE);
62 SSL_CONF_CTX_set_ssl_ctx(cctx, ctx);
63 for (i = 0; i < sk_CONF_VALUE_num(sect); i++) {
64 int rv;
65 cnf = sk_CONF_VALUE_value(sect, i);
66 rv = SSL_CONF_cmd(cctx, cnf->name, cnf->value);
67 if (rv > 0)
68 continue;
69 if (rv != -2) {
70 fprintf(stderr, "Error processing %s = %s\n",
71 cnf->name, cnf->value);
72 ERR_print_errors_fp(stderr);
73 goto err;
74 }
75 if (strcmp(cnf->name, "Port") == 0) {
76 port = cnf->value;
77 } else {
78 fprintf(stderr, "Unknown configuration option %s\n", cnf->name);
79 goto err;
80 }
81 }
82
83 if (!SSL_CONF_CTX_finish(cctx)) {
84 fprintf(stderr, "Finish error\n");
85 ERR_print_errors_fp(stderr);
86 goto err;
87 }
88
89 /* Setup server side SSL bio */
90 ssl_bio = BIO_new_ssl(ctx, 0);
91
92 if ((in = BIO_new_accept(port)) == NULL)
93 goto err;
94
95 /*
96 * This means that when a new connection is accepted on 'in', The ssl_bio
97 * will be 'duplicated' and have the new socket BIO push into it.
98 * Basically it means the SSL BIO will be automatically setup
99 */
100 BIO_set_accept_bios(in, ssl_bio);
101 ssl_bio = NULL;
102
103 again:
104 /*
105 * The first call will setup the accept socket, and the second will get a
106 * socket. In this loop, the first actual accept will occur in the
107 * BIO_read() function.
108 */
109
110 if (BIO_do_accept(in) <= 0)
111 goto err;
112
113 for (;;) {
114 i = BIO_read(in, buf, 512);
115 if (i == 0) {
116 /*
117 * If we have finished, remove the underlying BIO stack so the
118 * next time we call any function for this BIO, it will attempt
119 * to do an accept
120 */
121 printf("Done\n");
122 tmp = BIO_pop(in);
123 BIO_free_all(tmp);
124 goto again;
125 }
126 if (i < 0) {
127 if (BIO_should_retry(in))
128 continue;
129 goto err;
130 }
131 fwrite(buf, 1, i, stdout);
132 fflush(stdout);
133 }
134
135 ret = EXIT_SUCCESS;
136 err:
137 if (ret != EXIT_SUCCESS)
138 ERR_print_errors_fp(stderr);
139 BIO_free(in);
140 BIO_free_all(ssl_bio);
141 return ret;
142 }
143