1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
#include <openssl/ssl.h>
/*
* Demo 1: Client — Managed Connection — Blocking
* ==============================================
*
* This is an example of (part of) an application which uses libssl in a simple,
* synchronous, blocking fashion. The functions show all interactions with
* libssl the application makes, and would hypothetically be linked into a
* larger application.
*/
/*
* The application is initializing and wants an SSL_CTX which it will use for
* some number of outgoing connections, which it creates in subsequent calls to
* new_conn. The application may also call this function multiple times to
* create multiple SSL_CTX.
*/
SSL_CTX *create_ssl_ctx(void)
{
SSL_CTX *ctx;
#ifdef USE_QUIC
ctx = SSL_CTX_new(OSSL_QUIC_client_method());
#else
ctx = SSL_CTX_new(TLS_client_method());
#endif
if (ctx == NULL)
return NULL;
/* Enable trust chain verification. */
SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
/* Load default root CA store. */
if (SSL_CTX_set_default_verify_paths(ctx) == 0) {
SSL_CTX_free(ctx);
return NULL;
}
return ctx;
}
/*
* The application wants to create a new outgoing connection using a given
* SSL_CTX.
*
* hostname is a string like "openssl.org:443" or "[::1]:443".
*/
BIO *new_conn(SSL_CTX *ctx, const char *hostname)
{
BIO *out;
SSL *ssl = NULL;
const char *bare_hostname;
#ifdef USE_QUIC
static const unsigned char alpn[] = {5, 'd', 'u', 'm', 'm', 'y'};
#endif
out = BIO_new_ssl_connect(ctx);
if (out == NULL)
return NULL;
if (BIO_get_ssl(out, &ssl) == 0) {
BIO_free_all(out);
return NULL;
}
if (BIO_set_conn_hostname(out, hostname) == 0) {
BIO_free_all(out);
return NULL;
}
/* Returns the parsed hostname extracted from the hostname:port string. */
bare_hostname = BIO_get_conn_hostname(out);
if (bare_hostname == NULL) {
BIO_free_all(out);
return NULL;
}
/* Tell the SSL object the hostname to check certificates against. */
if (SSL_set1_host(ssl, bare_hostname) <= 0) {
BIO_free_all(out);
return NULL;
}
#ifdef USE_QUIC
/* Configure ALPN, which is required for QUIC. */
if (SSL_set_alpn_protos(ssl, alpn, sizeof(alpn))) {
/* Note: SSL_set_alpn_protos returns 1 for failure. */
BIO_free_all(out);
return NULL;
}
#endif
return out;
}
/*
* The application wants to send some block of data to the peer.
* This is a blocking call.
*/
int tx(BIO *bio, const void *buf, int buf_len)
{
return BIO_write(bio, buf, buf_len);
}
/*
* The application wants to receive some block of data from
* the peer. This is a blocking call.
*/
int rx(BIO *bio, void *buf, int buf_len)
{
return BIO_read(bio, buf, buf_len);
}
/*
* The application wants to close the connection and free bookkeeping
* structures.
*/
void teardown(BIO *bio)
{
BIO_free_all(bio);
}
/*
* The application is shutting down and wants to free a previously
* created SSL_CTX.
*/
void teardown_ctx(SSL_CTX *ctx)
{
SSL_CTX_free(ctx);
}
/*
* ============================================================================
* Example driver for the above code. This is just to demonstrate that the code
* works and is not intended to be representative of a real application.
*/
int main(int argc, char **argv)
{
static char msg[384], host_port[300];
SSL_CTX *ctx = NULL;
BIO *b = NULL;
char buf[2048];
int l, res = 1;
if (argc < 3) {
fprintf(stderr, "usage: %s host port\n", argv[0]);
goto fail;
}
snprintf(host_port, sizeof(host_port), "%s:%s\n", argv[1], argv[2]);
snprintf(msg, sizeof(msg),
"GET / HTTP/1.0\r\nHost: %s\r\n\r\n", argv[1]);
ctx = create_ssl_ctx();
if (ctx == NULL) {
fprintf(stderr, "could not create context\n");
goto fail;
}
b = new_conn(ctx, host_port);
if (b == NULL) {
fprintf(stderr, "could not create conn\n");
goto fail;
}
if (tx(b, msg, sizeof(msg)) < sizeof(msg)) {
fprintf(stderr, "tx error\n");
goto fail;
}
for (;;) {
l = rx(b, buf, sizeof(buf));
if (l <= 0)
break;
fwrite(buf, 1, l, stdout);
}
res = 0;
fail:
if (b != NULL)
teardown(b);
if (ctx != NULL)
teardown_ctx(ctx);
return res;
}
|
