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Diffstat (limited to 'src/lib/libssl/doc/BIO_f_ssl.3')
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1 | .Dd $Mdocdate: October 12 2014 $ | ||
2 | .Dt BIO_F_SSL 3 | ||
3 | .Os | ||
4 | .Sh NAME | ||
5 | .Nm BIO_f_ssl , | ||
6 | .Nm BIO_set_ssl , | ||
7 | .Nm BIO_get_ssl , | ||
8 | .Nm BIO_set_ssl_mode , | ||
9 | .Nm BIO_set_ssl_renegotiate_bytes , | ||
10 | .Nm BIO_get_num_renegotiates , | ||
11 | .Nm BIO_set_ssl_renegotiate_timeout , | ||
12 | .Nm BIO_new_ssl , | ||
13 | .Nm BIO_new_ssl_connect , | ||
14 | .Nm BIO_new_buffer_ssl_connect , | ||
15 | .Nm BIO_ssl_copy_session_id , | ||
16 | .Nm BIO_ssl_shutdown | ||
17 | .Nd SSL BIO | ||
18 | .Sh SYNOPSIS | ||
19 | .In openssl/bio.h | ||
20 | .In openssl/ssl.h | ||
21 | .Ft BIO_METHOD * | ||
22 | .Fn BIO_f_ssl void | ||
23 | .Fd #define BIO_set_ssl(b,ssl,c) BIO_ctrl(b,BIO_C_SET_SSL,c,(char *)ssl) | ||
24 | .Fd #define BIO_get_ssl(b,sslp) BIO_ctrl(b,BIO_C_GET_SSL,0,(char *)sslp) | ||
25 | .Fd #define BIO_set_ssl_mode(b,client) BIO_ctrl(b,BIO_C_SSL_MODE,client,NULL) | ||
26 | .Fd #define BIO_set_ssl_renegotiate_bytes(b,num) \ | ||
27 | BIO_ctrl(b,BIO_C_SET_SSL_RENEGOTIATE_BYTES,num,NULL) | ||
28 | .Fd #define BIO_set_ssl_renegotiate_timeout(b,seconds) \ | ||
29 | BIO_ctrl(b,BIO_C_SET_SSL_RENEGOTIATE_TIMEOUT,seconds,NULL) | ||
30 | .Fd #define BIO_get_num_renegotiates(b) \ | ||
31 | BIO_ctrl(b,BIO_C_SET_SSL_NUM_RENEGOTIATES,0,NULL) | ||
32 | .Ft BIO * | ||
33 | .Fn BIO_new_ssl "SSL_CTX *ctx" "int client" | ||
34 | .Ft BIO * | ||
35 | .Fn BIO_new_ssl_connect "SSL_CTX *ctx" | ||
36 | .Ft BIO * | ||
37 | .Fn BIO_new_buffer_ssl_connect "SSL_CTX *ctx" | ||
38 | .Ft int | ||
39 | .Fn BIO_ssl_copy_session_id "BIO *to" "BIO *from" | ||
40 | .Ft void | ||
41 | .Fn BIO_ssl_shutdown "BIO *bio" | ||
42 | .Fd #define BIO_do_handshake(b) BIO_ctrl(b,BIO_C_DO_STATE_MACHINE,0,NULL) | ||
43 | .Sh DESCRIPTION | ||
44 | .Fn BIO_f_ssl | ||
45 | returns the | ||
46 | .Vt SSL | ||
47 | .Vt BIO | ||
48 | method. | ||
49 | This is a filter | ||
50 | .Vt BIO | ||
51 | which is a wrapper around the OpenSSL | ||
52 | .Vt SSL | ||
53 | routines adding a | ||
54 | .Vt BIO | ||
55 | .Dq flavor | ||
56 | to SSL I/O. | ||
57 | .Pp | ||
58 | I/O performed on an | ||
59 | .Vt SSL | ||
60 | .Vt BIO | ||
61 | communicates using the SSL protocol with | ||
62 | the | ||
63 | .Vt SSL Ns 's | ||
64 | read and write | ||
65 | .Vt BIO Ns s. | ||
66 | If an SSL connection is not established then an attempt is made to establish | ||
67 | one on the first I/O call. | ||
68 | .Pp | ||
69 | If a | ||
70 | .Vt BIO | ||
71 | is appended to an | ||
72 | .Vt SSL | ||
73 | .Vt BIO | ||
74 | using | ||
75 | .Xr BIO_push 3 | ||
76 | it is automatically used as the | ||
77 | .Vt SSL | ||
78 | .Vt BIO Ns 's read and write | ||
79 | .Vt BIO Ns s. | ||
80 | .Pp | ||
81 | Calling | ||
82 | .Xr BIO_reset 3 | ||
83 | on an | ||
84 | .Vt SSL | ||
85 | .Vt BIO | ||
86 | closes down any current SSL connection by calling | ||
87 | .Xr SSL_shutdown 3 . | ||
88 | .Xr BIO_reset | ||
89 | is then sent to the next | ||
90 | .Vt BIO | ||
91 | in the chain; this will typically disconnect the underlying transport. | ||
92 | The | ||
93 | .Vt SSL | ||
94 | .Vt BIO | ||
95 | is then reset to the initial accept or connect state. | ||
96 | .Pp | ||
97 | If the close flag is set when an | ||
98 | .Vt SSL | ||
99 | .Vt BIO | ||
100 | is freed then the internal | ||
101 | .Vt SSL | ||
102 | structure is also freed using | ||
103 | .Xr SSL_free 3 . | ||
104 | .Pp | ||
105 | .Fn BIO_set_ssl | ||
106 | sets the internal | ||
107 | .Vt SSL | ||
108 | pointer of | ||
109 | .Vt BIO | ||
110 | .Fa b | ||
111 | to | ||
112 | .Fa ssl | ||
113 | using | ||
114 | the close flag | ||
115 | .Fa c . | ||
116 | .Pp | ||
117 | .Fn BIO_get_ssl | ||
118 | retrieves the | ||
119 | .Vt SSL | ||
120 | pointer of | ||
121 | .Vt BIO | ||
122 | .Fa b ; | ||
123 | it can then be manipulated using the standard SSL library functions. | ||
124 | .Pp | ||
125 | .Fn BIO_set_ssl_mode | ||
126 | sets the | ||
127 | .Vt SSL | ||
128 | .Vt BIO | ||
129 | mode to | ||
130 | .Fa client . | ||
131 | If | ||
132 | .Fa client | ||
133 | is 1, client mode is set. | ||
134 | If | ||
135 | .Fa client | ||
136 | is 0, server mode is set. | ||
137 | .Pp | ||
138 | .Fn BIO_set_ssl_renegotiate_bytes | ||
139 | sets the renegotiate byte count to | ||
140 | .Fa num . | ||
141 | When set after every | ||
142 | .Fa num | ||
143 | bytes of I/O (read and write) the SSL session is automatically renegotiated. | ||
144 | .Fa num | ||
145 | must be at least 512 bytes. | ||
146 | .Pp | ||
147 | .Fn BIO_set_ssl_renegotiate_timeout | ||
148 | sets the renegotiate timeout to | ||
149 | .Fa seconds . | ||
150 | When the renegotiate timeout elapses the session is automatically renegotiated. | ||
151 | .Pp | ||
152 | .Fn BIO_get_num_renegotiates | ||
153 | returns the total number of session renegotiations due to I/O or timeout. | ||
154 | .Pp | ||
155 | .Fn BIO_new_ssl | ||
156 | allocates an | ||
157 | .Vt SSL | ||
158 | .Vt BIO | ||
159 | using | ||
160 | .Vt SSL_CTX | ||
161 | .Va ctx | ||
162 | and using client mode if | ||
163 | .Fa client | ||
164 | is nonzero. | ||
165 | .Pp | ||
166 | .Fn BIO_new_ssl_connect | ||
167 | creates a new | ||
168 | .Vt BIO | ||
169 | chain consisting of an | ||
170 | .Vt SSL | ||
171 | .Vt BIO | ||
172 | (using | ||
173 | .Fa ctx ) | ||
174 | followed by a connect BIO. | ||
175 | .Pp | ||
176 | .Fn BIO_new_buffer_ssl_connect | ||
177 | creates a new | ||
178 | .Vt BIO | ||
179 | chain consisting of a buffering | ||
180 | .Vt BIO , | ||
181 | an | ||
182 | .Vt SSL | ||
183 | .Vt BIO | ||
184 | (using | ||
185 | .Fa ctx ) | ||
186 | and a connect | ||
187 | .Vt BIO . | ||
188 | .Pp | ||
189 | .Fn BIO_ssl_copy_session_id | ||
190 | copies an SSL session id between | ||
191 | .Vt BIO | ||
192 | chains | ||
193 | .Fa from | ||
194 | and | ||
195 | .Fa to . | ||
196 | It does this by locating the | ||
197 | .Vt SSL | ||
198 | .Vt BIO Ns s | ||
199 | in each chain and calling | ||
200 | .Xr SSL_copy_session_id 3 | ||
201 | on the internal | ||
202 | .Vt SSL | ||
203 | pointer. | ||
204 | .Pp | ||
205 | .Fn BIO_ssl_shutdown | ||
206 | closes down an SSL connection on | ||
207 | .Vt BIO | ||
208 | chain | ||
209 | .Fa bio . | ||
210 | It does this by locating the | ||
211 | .Vt SSL | ||
212 | .Vt BIO | ||
213 | in the | ||
214 | chain and calling | ||
215 | .Xr SSL_shutdown 3 | ||
216 | on its internal | ||
217 | .Vt SSL | ||
218 | pointer. | ||
219 | .Pp | ||
220 | .Fn BIO_do_handshake | ||
221 | attempts to complete an SSL handshake on the supplied | ||
222 | .Vt BIO | ||
223 | and establish the SSL connection. | ||
224 | It returns 1 if the connection was established successfully. | ||
225 | A zero or negative value is returned if the connection could not be | ||
226 | established; the call | ||
227 | .Xr BIO_should_retry 3 | ||
228 | should be used for non blocking connect | ||
229 | .Vt BIO Ns s | ||
230 | to determine if the call should be retried. | ||
231 | If an SSL connection has already been established this call has no effect. | ||
232 | .Sh NOTES | ||
233 | .Vt SSL | ||
234 | .Vt BIO Ns s | ||
235 | are exceptional in that if the underlying transport is non-blocking they can | ||
236 | still request a retry in exceptional circumstances. | ||
237 | Specifically this will happen if a session renegotiation takes place during a | ||
238 | .Xr BIO_read 3 | ||
239 | operation. | ||
240 | One case where this happens is when SGC or step up occurs. | ||
241 | .Pp | ||
242 | In OpenSSL 0.9.6 and later the SSL flag | ||
243 | .Dv SSL_AUTO_RETRY | ||
244 | can be set to disable this behaviour. | ||
245 | In other words, when this flag is set an | ||
246 | .Vt SSL | ||
247 | .Vt BIO | ||
248 | using a blocking transport will never request a retry. | ||
249 | .Pp | ||
250 | Since unknown | ||
251 | .Xr BIO_ctrl 3 | ||
252 | operations are sent through filter | ||
253 | .Vt BIO Ns s | ||
254 | the server name and port can be set using | ||
255 | .Xr BIO_set_host 3 | ||
256 | on the | ||
257 | .Vt BIO | ||
258 | returned by | ||
259 | .Fn BIO_new_ssl_connect | ||
260 | without having to locate the connect | ||
261 | .Vt BIO | ||
262 | first. | ||
263 | .Pp | ||
264 | Applications do not have to call | ||
265 | .Fn BIO_do_handshake | ||
266 | but may wish to do so to separate the handshake process from other I/O | ||
267 | processing. | ||
268 | .Sh RETURN VALUES | ||
269 | .\" XXX | ||
270 | This section is incomplete. | ||
271 | .Sh EXAMPLE | ||
272 | This SSL/TLS client example attempts to retrieve a page from an SSL/TLS web | ||
273 | server. | ||
274 | The I/O routines are identical to those of the unencrypted example in | ||
275 | .Xr BIO_s_connect 3 . | ||
276 | .Bd -literal | ||
277 | BIO *sbio, *out; | ||
278 | int len; | ||
279 | char tmpbuf[1024]; | ||
280 | SSL_CTX *ctx; | ||
281 | SSL *ssl; | ||
282 | |||
283 | ERR_load_crypto_strings(); | ||
284 | ERR_load_SSL_strings(); | ||
285 | OpenSSL_add_all_algorithms(); | ||
286 | |||
287 | /* | ||
288 | * We would seed the PRNG here if the platform didn't do it automatically | ||
289 | */ | ||
290 | |||
291 | ctx = SSL_CTX_new(SSLv23_client_method()); | ||
292 | |||
293 | /* | ||
294 | * We'd normally set some stuff like the verify paths and mode here because | ||
295 | * as things stand this will connect to any server whose certificate is | ||
296 | * signed by any CA. | ||
297 | */ | ||
298 | |||
299 | sbio = BIO_new_ssl_connect(ctx); | ||
300 | |||
301 | BIO_get_ssl(sbio, &ssl); | ||
302 | |||
303 | if (!ssl) { | ||
304 | fprintf(stderr, "Can't locate SSL pointer\en"); | ||
305 | /* whatever ... */ | ||
306 | } | ||
307 | |||
308 | /* Don't want any retries */ | ||
309 | SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY); | ||
310 | |||
311 | /* We might want to do other things with ssl here */ | ||
312 | |||
313 | BIO_set_conn_hostname(sbio, "localhost:https"); | ||
314 | |||
315 | out = BIO_new_fp(stdout, BIO_NOCLOSE); | ||
316 | if (BIO_do_connect(sbio) <= 0) { | ||
317 | fprintf(stderr, "Error connecting to server\en"); | ||
318 | ERR_print_errors_fp(stderr); | ||
319 | /* whatever ... */ | ||
320 | } | ||
321 | |||
322 | if (BIO_do_handshake(sbio) <= 0) { | ||
323 | fprintf(stderr, "Error establishing SSL connection\en"); | ||
324 | ERR_print_errors_fp(stderr); | ||
325 | /* whatever ... */ | ||
326 | } | ||
327 | |||
328 | /* Could examine ssl here to get connection info */ | ||
329 | |||
330 | BIO_puts(sbio, "GET / HTTP/1.0\en\en"); | ||
331 | for (;;) { | ||
332 | len = BIO_read(sbio, tmpbuf, 1024); | ||
333 | if(len <= 0) break; | ||
334 | BIO_write(out, tmpbuf, len); | ||
335 | } | ||
336 | BIO_free_all(sbio); | ||
337 | BIO_free(out); | ||
338 | .Ed | ||
339 | .Pp | ||
340 | Here is a simple server example. | ||
341 | It makes use of a buffering | ||
342 | .Vt BIO | ||
343 | to allow lines to be read from the | ||
344 | .Vt SSL | ||
345 | .Vt BIO | ||
346 | using | ||
347 | .Xr BIO_gets 3 . | ||
348 | It creates a pseudo web page containing the actual request from a client and | ||
349 | also echoes the request to standard output. | ||
350 | .Bd -literal | ||
351 | BIO *sbio, *bbio, *acpt, *out; | ||
352 | int len; | ||
353 | char tmpbuf[1024]; | ||
354 | SSL_CTX *ctx; | ||
355 | SSL *ssl; | ||
356 | |||
357 | ERR_load_crypto_strings(); | ||
358 | ERR_load_SSL_strings(); | ||
359 | OpenSSL_add_all_algorithms(); | ||
360 | |||
361 | /* Might seed PRNG here */ | ||
362 | |||
363 | ctx = SSL_CTX_new(SSLv23_server_method()); | ||
364 | |||
365 | if (!SSL_CTX_use_certificate_file(ctx,"server.pem",SSL_FILETYPE_PEM) | ||
366 | || !SSL_CTX_use_PrivateKey_file(ctx,"server.pem",SSL_FILETYPE_PEM) | ||
367 | || !SSL_CTX_check_private_key(ctx)) { | ||
368 | fprintf(stderr, "Error setting up SSL_CTX\en"); | ||
369 | ERR_print_errors_fp(stderr); | ||
370 | return 0; | ||
371 | } | ||
372 | |||
373 | /* | ||
374 | * Might do other things here like setting verify locations and DH and/or | ||
375 | * RSA temporary key callbacks | ||
376 | */ | ||
377 | |||
378 | /* New SSL BIO setup as server */ | ||
379 | sbio = BIO_new_ssl(ctx,0); | ||
380 | |||
381 | BIO_get_ssl(sbio, &ssl); | ||
382 | |||
383 | if (!ssl) { | ||
384 | fprintf(stderr, "Can't locate SSL pointer\en"); | ||
385 | /* whatever ... */ | ||
386 | } | ||
387 | |||
388 | /* Don't want any retries */ | ||
389 | SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY); | ||
390 | |||
391 | /* Create the buffering BIO */ | ||
392 | |||
393 | bbio = BIO_new(BIO_f_buffer()); | ||
394 | |||
395 | /* Add to chain */ | ||
396 | sbio = BIO_push(bbio, sbio); | ||
397 | |||
398 | acpt = BIO_new_accept("4433"); | ||
399 | |||
400 | /* | ||
401 | * By doing this when a new connection is established we automatically | ||
402 | * have sbio inserted into it. The BIO chain is now 'swallowed' by the | ||
403 | * accept BIO and will be freed when the accept BIO is freed. | ||
404 | */ | ||
405 | |||
406 | BIO_set_accept_bios(acpt,sbio); | ||
407 | |||
408 | out = BIO_new_fp(stdout, BIO_NOCLOSE); | ||
409 | |||
410 | /* Setup accept BIO */ | ||
411 | if (BIO_do_accept(acpt) <= 0) { | ||
412 | fprintf(stderr, "Error setting up accept BIO\en"); | ||
413 | ERR_print_errors_fp(stderr); | ||
414 | return 0; | ||
415 | } | ||
416 | |||
417 | /* Now wait for incoming connection */ | ||
418 | if (BIO_do_accept(acpt) <= 0) { | ||
419 | fprintf(stderr, "Error in connection\en"); | ||
420 | ERR_print_errors_fp(stderr); | ||
421 | return 0; | ||
422 | } | ||
423 | |||
424 | /* We only want one connection so remove and free accept BIO */ | ||
425 | |||
426 | sbio = BIO_pop(acpt); | ||
427 | |||
428 | BIO_free_all(acpt); | ||
429 | |||
430 | if (BIO_do_handshake(sbio) <= 0) { | ||
431 | fprintf(stderr, "Error in SSL handshake\en"); | ||
432 | ERR_print_errors_fp(stderr); | ||
433 | return 0; | ||
434 | } | ||
435 | |||
436 | BIO_puts(sbio, "HTTP/1.0 200 OK\er\enContent-type: text/plain\er\en\er\en"); | ||
437 | BIO_puts(sbio, "\er\enConnection Established\er\enRequest headers:\er\en"); | ||
438 | BIO_puts(sbio, "--------------------------------------------------\er\en"); | ||
439 | |||
440 | for (;;) { | ||
441 | len = BIO_gets(sbio, tmpbuf, 1024); | ||
442 | if (len <= 0) | ||
443 | break; | ||
444 | BIO_write(sbio, tmpbuf, len); | ||
445 | BIO_write(out, tmpbuf, len); | ||
446 | /* Look for blank line signifying end of headers */ | ||
447 | if ((tmpbuf[0] == '\er') || (tmpbuf[0] == '\en')) | ||
448 | break; | ||
449 | } | ||
450 | |||
451 | BIO_puts(sbio, "--------------------------------------------------\er\en"); | ||
452 | BIO_puts(sbio, "\er\en"); | ||
453 | |||
454 | /* Since there is a buffering BIO present we had better flush it */ | ||
455 | BIO_flush(sbio); | ||
456 | |||
457 | BIO_free_all(sbio); | ||
458 | .Ed | ||
459 | .Sh BUGS | ||
460 | In OpenSSL versions before 1.0.0 the | ||
461 | .Xr BIO_pop 3 | ||
462 | call was handled incorrectly: | ||
463 | the I/O BIO reference count was incorrectly incremented (instead of | ||
464 | decremented) and dissociated with the | ||
465 | .Vt SSL | ||
466 | .Vt BIO | ||
467 | even if the | ||
468 | .Vt SSL | ||
469 | .Vt BIO | ||
470 | was not | ||
471 | explicitly being popped (e.g., a pop higher up the chain). | ||
472 | Applications which included workarounds for this bug (e.g., freeing BIOs more | ||
473 | than once) should be modified to handle this fix or they may free up an already | ||
474 | freed | ||
475 | .Vt BIO . | ||