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gnutls_io.c @ bd2b48b

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asynciodebian/masterproxy-ticket

Last change on this file since bd2b48b was bd2b48b, checked in by Fiona Klute <fiona.klute@…>, 2 years ago

Immediately retry on EINTR or EAGAIN for blocking receive

Proxy TLS connections failed with EAGAIN in tests while trying to read
the response header if the server sent a large ticket, presumably
because records had to wait for the ticket to be passed. This fixes
the issue.

Property mode set to 100644

File size: 30.9 KB

Line
1	/*
2	* Copyright 2004-2005 Paul Querna
3	* Copyright 2008 Nikos Mavrogiannopoulos
4	* Copyright 2011 Dash Shendy
5	* Copyright 2015-2017 Fiona Klute
6	*
7	* Licensed under the Apache License, Version 2.0 (the "License");
8	* you may 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,
15	* WITHOUT 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
20	#include "mod_gnutls.h"
21
22	#ifdef APLOG_USE_MODULE
23	APLOG_USE_MODULE(gnutls);
24	#endif
25
26	#if defined(__GNUC__) && __GNUC__ < 5 && !defined(__clang__)
27	#include <inttypes.h>
28	#endif
29
30	/**
31	* @file
32	* Describe how the GnuTLS Filter system works here
33	* - Basicly the same as what mod_ssl does with OpenSSL.
34	*
35	*/
36
37	#define HTTP_ON_HTTPS_PORT \
38	"GET /" CRLF
39
40	#define HTTP_ON_HTTPS_PORT_BUCKET(alloc) \
41	apr_bucket_immortal_create(HTTP_ON_HTTPS_PORT, \
42	sizeof(HTTP_ON_HTTPS_PORT) - 1, \
43	alloc)
44
45	#define IS_PROXY_STR(c) \
46	((c->is_proxy == GNUTLS_ENABLED_TRUE) ? "proxy " : "")
47
48	/**
49	* Convert `APR_EINTR` or `APR_EAGAIN` to the matching errno. Needed
50	* to pass the status on to GnuTLS from the pull and push functions.
51	*/
52	#define EAI_APR_TO_RAW(s) (APR_STATUS_IS_EAGAIN(s) ? EAGAIN : EINTR)
53
54
55
56	static apr_status_t gnutls_io_filter_error(ap_filter_t * f,
57	apr_bucket_brigade * bb,
58	apr_status_t status) {
59	mgs_handle_t ctxt = (mgs_handle_t ) f->ctx;
60	apr_bucket *bucket;
61
62	switch (status) {
63	case HTTP_BAD_REQUEST:
64	/* log the situation */
65	ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, f->c,
66	"GnuTLS handshake failed: HTTP spoken on HTTPS port; "
67	"trying to send HTML error page");
68	ctxt->status = -1;
69
70	/* fake the request line */
71	bucket = HTTP_ON_HTTPS_PORT_BUCKET(f->c->bucket_alloc);
72	break;
73
74	default:
75	return status;
76	}
77
78	APR_BRIGADE_INSERT_TAIL(bb, bucket);
79	bucket = apr_bucket_eos_create(f->c->bucket_alloc);
80	APR_BRIGADE_INSERT_TAIL(bb, bucket);
81
82	return APR_SUCCESS;
83	}
84
85	static int char_buffer_read(mgs_char_buffer_t * buffer, char *in, int inl) {
86	if (!buffer->length) {
87	return 0;
88	}
89
90	if (buffer->length > inl) {
91	/* we have have enough to fill the caller's buffer */
92	memmove(in, buffer->value, inl);
93	buffer->value += inl;
94	buffer->length -= inl;
95	} else {
96	/* swallow remainder of the buffer */
97	memmove(in, buffer->value, buffer->length);
98	inl = buffer->length;
99	buffer->value = NULL;
100	buffer->length = 0;
101	}
102
103	return inl;
104	}
105
106	static int char_buffer_write(mgs_char_buffer_t * buffer, char *in, int inl) {
107	buffer->value = in;
108	buffer->length = inl;
109	return inl;
110	}
111
112	/**
113	* From mod_ssl / ssl_engine_io.c
114	* This function will read from a brigade and discard the read buckets as it
115	* proceeds. It will read at most *len bytes.
116	*/
117	static apr_status_t brigade_consume(apr_bucket_brigade * bb,
118	apr_read_type_e block,
119	char c, apr_size_t len) {
120	apr_size_t actual = 0;
121	apr_status_t status = APR_SUCCESS;
122
123	while (!APR_BRIGADE_EMPTY(bb)) {
124	apr_bucket *b = APR_BRIGADE_FIRST(bb);
125	const char *str;
126	apr_size_t str_len;
127	apr_size_t consume;
128
129	/* Justin points out this is an http-ism that might
130	* not fit if brigade_consume is added to APR. Perhaps
131	* apr_bucket_read(eos_bucket) should return APR_EOF?
132	* Then this becomes mainline instead of a one-off.
133	*/
134	if (APR_BUCKET_IS_EOS(b)) {
135	status = APR_EOF;
136	break;
137	}
138
139	/* The reason I'm not offering brigade_consume yet
140	* across to apr-util is that the following call
141	* illustrates how borked that API really is. For
142	* this sort of case (caller provided buffer) it
143	* would be much more trivial for apr_bucket_consume
144	* to do all the work that follows, based on the
145	* particular characteristics of the bucket we are
146	* consuming here.
147	*/
148	status = apr_bucket_read(b, &str, &str_len, block);
149
150	if (status != APR_SUCCESS) {
151	if (APR_STATUS_IS_EOF(status)) {
152	/* This stream bucket was consumed */
153	apr_bucket_delete(b);
154	continue;
155	}
156	break;
157	}
158
159	if (str_len > 0) {
160	/* Do not block once some data has been consumed */
161	block = APR_NONBLOCK_READ;
162
163	/* Assure we don't overflow. */
164	consume =
165	(str_len + actual >
166	len) ? len - actual : str_len;
167
168	memcpy(c, str, consume);
169
170	c += consume;
171	actual += consume;
172
173	if (consume >= b->length) {
174	/* This physical bucket was consumed */
175	apr_bucket_delete(b);
176	} else {
177	/* Only part of this physical bucket was consumed */
178	b->start += consume;
179	b->length -= consume;
180	}
181	} else if (b->length == 0) {
182	apr_bucket_delete(b);
183	}
184
185	/* This could probably be actual == *len, but be safe from stray
186	* photons. */
187	if (actual >= *len) {
188	break;
189	}
190	}
191
192	*len = actual;
193	return status;
194	}
195
196	static apr_status_t gnutls_io_input_read(mgs_handle_t * ctxt,
197	char buf, apr_size_t len)
198	{
199	apr_size_t wanted = *len;
200	apr_size_t bytes = 0;
201	int rc;
202
203	*len = 0;
204
205	/* If we have something leftover from last time, try that first. */
206	if ((bytes = char_buffer_read(&ctxt->input_cbuf, buf, wanted))) {
207	*len = bytes;
208	if (ctxt->input_mode == AP_MODE_SPECULATIVE) {
209	/* We want to rollback this read. */
210	if (ctxt->input_cbuf.length > 0) {
211	ctxt->input_cbuf.value -= bytes;
212	ctxt->input_cbuf.length += bytes;
213	} else {
214	char_buffer_write(&ctxt->input_cbuf, buf,
215	(int) bytes);
216	}
217	return APR_SUCCESS;
218	}
219	/* This could probably be *len == wanted, but be safe from stray
220	* photons.
221	*/
222	if (*len >= wanted) {
223	return APR_SUCCESS;
224	}
225	if (ctxt->input_mode == AP_MODE_GETLINE) {
226	if (memchr(buf, APR_ASCII_LF, *len)) {
227	return APR_SUCCESS;
228	}
229	} else {
230	/* Down to a nonblock pattern as we have some data already
231	*/
232	ctxt->input_block = APR_NONBLOCK_READ;
233	}
234	}
235
236	if (ctxt->session == NULL) {
237	ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, ctxt->c,
238	"%s: GnuTLS session is NULL!", __func__);
239	return APR_EGENERAL;
240	}
241
242	while (1)
243	{
244	/* Note: The pull function sets ctxt->input_rc */
245	rc = gnutls_record_recv(ctxt->session, buf + bytes, wanted - bytes);
246
247	if (rc > 0) {
248	*len += rc;
249	if (ctxt->input_mode == AP_MODE_SPECULATIVE) {
250	/* We want to rollback this read. */
251	char_buffer_write(&ctxt->input_cbuf, buf,
252	rc);
253	}
254	return ctxt->input_rc;
255	} else if (rc == 0) {
256	/* EOF, return code depends on whether we still have data
257	* to return. */
258	if (*len > 0) {
259	ctxt->input_rc = APR_SUCCESS;
260	} else {
261	ctxt->input_rc = APR_EOF;
262	}
263	break;
264	} else { /* (rc < 0) */
265
266	if (rc == GNUTLS_E_INTERRUPTED \|\| rc == GNUTLS_E_AGAIN)
267	{
268	ap_log_cerror(APLOG_MARK, APLOG_TRACE2, ctxt->input_rc, ctxt->c,
269	"%s: looping recv after '%s' (%d)",
270	__func__, gnutls_strerror(rc), rc);
271	/* For a blocking read: Loop and try again immediately. */
272	if (ctxt->input_block != APR_NONBLOCK_READ)
273	continue;
274	} else if (rc == GNUTLS_E_REHANDSHAKE) {
275	/* A client has asked for a new Hankshake. Currently, we don't do it */
276	ap_log_cerror(APLOG_MARK, APLOG_INFO,
277	ctxt->input_rc,
278	ctxt->c,
279	"GnuTLS: Error reading data. Client Requested a New Handshake."
280	" (%d) '%s'", rc,
281	gnutls_strerror(rc));
282	} else if (rc == GNUTLS_E_WARNING_ALERT_RECEIVED) {
283	rc = gnutls_alert_get(ctxt->session);
284	ap_log_cerror(APLOG_MARK, APLOG_INFO,
285	ctxt->input_rc,
286	ctxt->c,
287	"GnuTLS: Warning Alert From Client: "
288	" (%d) '%s'", rc,
289	gnutls_alert_get_name(rc));
290	} else if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) {
291	rc = gnutls_alert_get(ctxt->session);
292	ap_log_cerror(APLOG_MARK, APLOG_INFO,
293	ctxt->input_rc,
294	ctxt->c,
295	"GnuTLS: Fatal Alert From Client: "
296	"(%d) '%s'", rc,
297	gnutls_alert_get_name(rc));
298	ctxt->input_rc = APR_EGENERAL;
299	break;
300	} else {
301	/* Some Other Error. Report it. Die. */
302	if (gnutls_error_is_fatal(rc)) {
303	ap_log_cerror(APLOG_MARK,
304	APLOG_INFO,
305	ctxt->input_rc,
306	ctxt->c,
307	"GnuTLS: Error reading data. (%d) '%s'",
308	rc,
309	gnutls_strerror(rc));
310	} else if (*len > 0) {
311	ctxt->input_rc = APR_SUCCESS;
312	break;
313	}
314	}
315
316	if (ctxt->input_rc == APR_SUCCESS) {
317	ap_log_cerror(APLOG_MARK, APLOG_INFO, ctxt->input_rc, ctxt->c,
318	"%s: GnuTLS error: %s (%d)",
319	__func__, gnutls_strerror(rc), rc);
320	ctxt->input_rc = APR_EGENERAL;
321	}
322	break;
323	}
324	}
325	return ctxt->input_rc;
326	}
327
328	static apr_status_t gnutls_io_input_getline(mgs_handle_t * ctxt,
329	char buf, apr_size_t len) {
330	const char *pos = NULL;
331	apr_status_t status;
332	apr_size_t tmplen = len, buflen = len, offset = 0;
333
334	*len = 0;
335
336	while (tmplen > 0) {
337	status = gnutls_io_input_read(ctxt, buf + offset, &tmplen);
338
339	if (status != APR_SUCCESS) {
340	return status;
341	}
342
343	*len += tmplen;
344
345	if ((pos = memchr(buf, APR_ASCII_LF, *len))) {
346	break;
347	}
348
349	offset += tmplen;
350	tmplen = buflen - offset;
351	}
352
353	if (pos) {
354	char *value;
355	int length;
356	apr_size_t bytes = pos - buf;
357
358	bytes += 1;
359	value = buf + bytes;
360	length = *len - bytes;
361
362	char_buffer_write(&ctxt->input_cbuf, value, length);
363
364	*len = bytes;
365	}
366
367	return APR_SUCCESS;
368	}
369
370	#define HANDSHAKE_MAX_TRIES 1024
371
372	static int gnutls_do_handshake(mgs_handle_t * ctxt) {
373	int ret;
374	int errcode;
375	int maxtries = HANDSHAKE_MAX_TRIES;
376
377	if (ctxt->status != 0 \|\| ctxt->session == NULL) {
378	return -1;
379	}
380
381	/* Enable SNI for proxy connections */
382	if (ctxt->is_proxy == GNUTLS_ENABLED_TRUE)
383	{
384	/* Get peer hostname from note left by mod_proxy */
385	const char *peer_hostname =
386	apr_table_get(ctxt->c->notes, PROXY_SNI_NOTE);
387	/* Used only as target for apr_ipsubnet_create() */
388	apr_ipsubnet_t *probe;
389	/* Check if the note is present (!= NULL) and NOT an IP
390	* address */
391	if ((peer_hostname) != NULL
392	&& (apr_ipsubnet_create(&probe, peer_hostname, NULL, ctxt->c->pool)
393	!= APR_SUCCESS))
394	{
395	ret = gnutls_server_name_set(ctxt->session, GNUTLS_NAME_DNS,
396	peer_hostname, strlen(peer_hostname));
397	if (ret != GNUTLS_E_SUCCESS)
398	ap_log_cerror(APLOG_MARK, APLOG_ERR, ret, ctxt->c,
399	"Could not set SNI '%s' for proxy connection: "
400	"%s (%d)",
401	peer_hostname, gnutls_strerror(ret), ret);
402	}
403	}
404
405	tryagain:
406	do {
407	ret = gnutls_handshake(ctxt->session);
408	maxtries--;
409	} while ((ret == GNUTLS_E_INTERRUPTED \|\| ret == GNUTLS_E_AGAIN)
410	&& maxtries > 0);
411
412	if (maxtries < 1) {
413	ctxt->status = -1;
414	ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, ctxt->c,
415	"GnuTLS: Handshake Failed. Hit Maximum Attempts");
416	if (ctxt->session) {
417	gnutls_alert_send(ctxt->session, GNUTLS_AL_FATAL,
418	gnutls_error_to_alert
419	(GNUTLS_E_INTERNAL_ERROR, NULL));
420	gnutls_deinit(ctxt->session);
421	}
422	ctxt->session = NULL;
423	return -1;
424	}
425
426	if (ret < 0) {
427	if (ret == GNUTLS_E_WARNING_ALERT_RECEIVED
428	\|\| ret == GNUTLS_E_FATAL_ALERT_RECEIVED) {
429	errcode = gnutls_alert_get(ctxt->session);
430	ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, ctxt->c,
431	"GnuTLS: Handshake Alert (%d) '%s'.",
432	errcode, gnutls_alert_get_name(errcode));
433	}
434
435	if (!gnutls_error_is_fatal(ret)) {
436	ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, ctxt->c,
437	"GnuTLS: Non-Fatal Handshake Error: (%d) '%s'",
438	ret, gnutls_strerror(ret));
439	goto tryagain;
440	}
441	ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, ctxt->c,
442	"GnuTLS: Handshake Failed (%d) '%s'", ret,
443	gnutls_strerror(ret));
444	ctxt->status = -1;
445	if (ctxt->session) {
446	gnutls_alert_send(ctxt->session, GNUTLS_AL_FATAL,
447	gnutls_error_to_alert(ret,
448	NULL));
449	gnutls_deinit(ctxt->session);
450	}
451	ctxt->session = NULL;
452	return ret;
453	} else {
454	/* all done with the handshake */
455	ctxt->status = 1;
456	if (gnutls_session_is_resumed(ctxt->session))
457	{
458	ap_log_cerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, ctxt->c,
459	"%s: TLS session resumed.", __func__);
460	}
461	return GNUTLS_E_SUCCESS;
462	}
463	}
464
465	int mgs_rehandshake(mgs_handle_t * ctxt) {
466	int rv;
467
468	if (ctxt->session == NULL)
469	return -1;
470
471	rv = gnutls_rehandshake(ctxt->session);
472
473	if (rv != 0) {
474	/* the client did not want to rehandshake. goodbye */
475	ap_log_cerror(APLOG_MARK, APLOG_WARNING, 0, ctxt->c,
476	"GnuTLS: Client Refused Rehandshake request.");
477	return -1;
478	}
479
480	ctxt->status = 0;
481
482	rv = gnutls_do_handshake(ctxt);
483
484	return rv;
485	}
486
487
488
489	/**
490	* Close the TLS session associated with the given connection
491	* structure and free its resources
492	*
493	* @param ctxt the mod_gnutls session context
494	*
495	* @return a GnuTLS status code, hopefully `GNUTLS_E_SUCCESS`
496	*/
497	static int mgs_bye(mgs_handle_t* ctxt)
498	{
499	int ret = GNUTLS_E_SUCCESS;
500	/* End Of Connection */
501	if (ctxt->session != NULL)
502	{
503	/* Try A Clean Shutdown */
504	do {
505	ret = gnutls_bye(ctxt->session, GNUTLS_SHUT_WR);
506	} while (ret == GNUTLS_E_INTERRUPTED \|\| ret == GNUTLS_E_AGAIN);
507	if (ret != GNUTLS_E_SUCCESS)
508	ap_log_cerror(APLOG_MARK, APLOG_DEBUG, APR_EGENERAL, ctxt->c,
509	"%s: Error while closing TLS %sconnection: "
510	"'%s' (%d)",
511	__func__, IS_PROXY_STR(ctxt),
512	gnutls_strerror(ret), (int) ret);
513	else
514	ap_log_cerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, ctxt->c,
515	"%s: TLS %sconnection closed.",
516	__func__, IS_PROXY_STR(ctxt));
517	/* De-Initialize Session */
518	gnutls_deinit(ctxt->session);
519	ctxt->session = NULL;
520	}
521	return ret;
522	}
523
524
525
526	apr_status_t mgs_filter_input(ap_filter_t * f,
527	apr_bucket_brigade * bb,
528	ap_input_mode_t mode,
529	apr_read_type_e block, apr_off_t readbytes)
530	{
531	apr_status_t status = APR_SUCCESS;
532	mgs_handle_t ctxt = (mgs_handle_t ) f->ctx;
533	apr_size_t len = sizeof (ctxt->input_buffer);
534
535	if (f->c->aborted) {
536	apr_bucket *bucket =
537	apr_bucket_eos_create(f->c->bucket_alloc);
538	APR_BRIGADE_INSERT_TAIL(bb, bucket);
539	ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, ctxt->c,
540	"%s: %sconnection aborted",
541	__func__, IS_PROXY_STR(ctxt));
542	return APR_ECONNABORTED;
543	}
544
545	if (ctxt->status == 0) {
546	int ret = gnutls_do_handshake(ctxt);
547	if (ret == GNUTLS_E_SUCCESS)
548	ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, ctxt->c,
549	"%s: TLS %sconnection opened.",
550	__func__, IS_PROXY_STR(ctxt));
551	}
552
553	if (ctxt->status < 0)
554	{
555	ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, ctxt->c,
556	"%s: %sconnection failed, cannot provide data!",
557	__func__, IS_PROXY_STR(ctxt));
558	apr_bucket *bucket =
559	apr_bucket_eos_create(f->c->bucket_alloc);
560	APR_BRIGADE_INSERT_TAIL(bb, bucket);
561	return APR_ECONNABORTED;
562	}
563
564	/* XXX: we don't currently support anything other than these modes. */
565	if (mode != AP_MODE_READBYTES && mode != AP_MODE_GETLINE &&
566	mode != AP_MODE_SPECULATIVE && mode != AP_MODE_INIT) {
567	return APR_ENOTIMPL;
568	}
569
570	ctxt->input_mode = mode;
571	ctxt->input_block = block;
572
573	if (ctxt->input_mode == AP_MODE_READBYTES \|\|
574	ctxt->input_mode == AP_MODE_SPECULATIVE) {
575	if (readbytes < 0) {
576	/* you're asking us to speculatively read a negative number of bytes! */
577	return APR_ENOTIMPL;
578	}
579	/* 'readbytes' and 'len' are of different integer types, which
580	* might have different lengths. Read sizes should be too
581	* small for 32 or 64 bit to matter, but we have to make
582	* sure. */
583	#if defined(__GNUC__) && __GNUC__ < 5 && !defined(__clang__)
584	if ((apr_size_t) readbytes < len)
585	{
586	/* If readbytes is negative the function fails in the
587	* check above, but the compiler doesn't get that. */
588	if (__builtin_expect(imaxabs(readbytes) > SIZE_MAX, 0))
589	{
590	ap_log_cerror(APLOG_MARK, APLOG_CRIT, APR_EINVAL, ctxt->c,
591	"%s: prevented buffer length overflow",
592	__func__);
593	return APR_EINVAL;
594	}
595	len = (apr_size_t) readbytes;
596	}
597	#else
598	if ((apr_size_t) readbytes < len
599	&& __builtin_add_overflow(readbytes, 0, &len))
600	{
601	ap_log_cerror(APLOG_MARK, APLOG_CRIT, APR_EINVAL, ctxt->c,
602	"%s: prevented buffer length overflow",
603	__func__);
604	return APR_EINVAL;
605	}
606	#endif
607	status =
608	gnutls_io_input_read(ctxt, ctxt->input_buffer, &len);
609	} else if (ctxt->input_mode == AP_MODE_GETLINE) {
610	status =
611	gnutls_io_input_getline(ctxt, ctxt->input_buffer,
612	&len);
613	} else {
614	/* We have no idea what you are talking about, so return an error. */
615	return APR_ENOTIMPL;
616	}
617
618	if (status != APR_SUCCESS)
619	{
620	/* no data for nonblocking read, return APR_EAGAIN */
621	if ((block == APR_NONBLOCK_READ) && APR_STATUS_IS_EINTR(status))
622	return APR_EAGAIN;
623
624	/* Close TLS session and free resources on EOF,
625	* gnutls_io_filter_error will add an EOS bucket */
626	if (APR_STATUS_IS_EOF(status))
627	mgs_bye(ctxt);
628
629	return gnutls_io_filter_error(f, bb, status);
630	}
631
632	/* Create a transient bucket out of the decrypted data. */
633	if (len > 0) {
634	apr_bucket *bucket =
635	apr_bucket_transient_create(ctxt->input_buffer, len,
636	f->c->bucket_alloc);
637	APR_BRIGADE_INSERT_TAIL(bb, bucket);
638	}
639
640	return status;
641	}
642
643	/**
644	* Try to flush the output bucket brigade.
645	*
646	* @param ctxt the mod_gnutls session context
647	*
648	* @return `1` on success, `-1` on failure.
649	*/
650	static ssize_t write_flush(mgs_handle_t * ctxt) {
651	apr_bucket *e;
652
653	if (!(ctxt->output_blen \|\| ctxt->output_length)) {
654	ctxt->output_rc = APR_SUCCESS;
655	return 1;
656	}
657
658	if (ctxt->output_blen) {
659	e = apr_bucket_transient_create(ctxt->output_buffer,
660	ctxt->output_blen,
661	ctxt->output_bb->
662	bucket_alloc);
663	/* we filled this buffer first so add it to the
664	* * head of the brigade
665	* */
666	APR_BRIGADE_INSERT_HEAD(ctxt->output_bb, e);
667	ctxt->output_blen = 0;
668	}
669
670	ctxt->output_length = 0;
671	e = apr_bucket_flush_create(ctxt->output_bb->bucket_alloc);
672	APR_BRIGADE_INSERT_TAIL(ctxt->output_bb, e);
673
674	ctxt->output_rc = ap_pass_brigade(ctxt->output_filter->next,
675	ctxt->output_bb);
676	/* clear the brigade to be ready for next time */
677	apr_brigade_cleanup(ctxt->output_bb);
678
679	return (ctxt->output_rc == APR_SUCCESS) ? 1 : -1;
680	}
681
682	apr_status_t mgs_filter_output(ap_filter_t * f, apr_bucket_brigade * bb) {
683	int ret;
684	mgs_handle_t ctxt = (mgs_handle_t ) f->ctx;
685	apr_status_t status = APR_SUCCESS;
686	apr_read_type_e rblock = APR_NONBLOCK_READ;
687
688	if (f->c->aborted) {
689	apr_brigade_cleanup(bb);
690	return APR_ECONNABORTED;
691	}
692
693	if (ctxt->status == 0) {
694	ret = gnutls_do_handshake(ctxt);
695	if (ret == GNUTLS_E_SUCCESS)
696	ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, ctxt->c,
697	"%s: TLS %sconnection opened.",
698	__func__, IS_PROXY_STR(ctxt));
699	}
700
701	if (ctxt->status < 0)
702	{
703	ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, ctxt->c,
704	"%s: %sconnection failed, refusing to send.",
705	__func__, IS_PROXY_STR(ctxt));
706	if (ctxt->is_proxy)
707	{
708	/* If mod_proxy receives an error while trying to send its
709	* request it sends an "invalid request" error to the
710	* client. By pretending we could send the request
711	* mod_proxy continues its processing and sends a proper
712	* "proxy error" message when there's no response to read. */
713	apr_bucket *bucket = apr_bucket_eos_create(f->c->bucket_alloc);
714	APR_BRIGADE_INSERT_TAIL(bb, bucket);
715	return APR_SUCCESS;
716	}
717	else
718	return APR_ECONNABORTED;
719	}
720
721	while (!APR_BRIGADE_EMPTY(bb)) {
722	apr_bucket *bucket = APR_BRIGADE_FIRST(bb);
723
724	if (APR_BUCKET_IS_EOS(bucket)) {
725	return ap_pass_brigade(f->next, bb);
726	} else if (APR_BUCKET_IS_FLUSH(bucket)) {
727	/* Try Flush */
728	if (write_flush(ctxt) < 0) {
729	/* Flush Error */
730	return ctxt->output_rc;
731	}
732	/* cleanup! */
733	apr_bucket_delete(bucket);
734	} else if (AP_BUCKET_IS_EOC(bucket)) {
735	/* End Of Connection, close TLS session and free
736	* resources */
737	mgs_bye(ctxt);
738	/* cleanup! */
739	apr_bucket_delete(bucket);
740	/* Pass next brigade! */
741	return ap_pass_brigade(f->next, bb);
742	} else {
743	/* filter output */
744	const char *data;
745	apr_size_t len;
746
747	status = apr_bucket_read(bucket, &data, &len, rblock);
748
749	if (APR_STATUS_IS_EAGAIN(status)) {
750	/* No data available so Flush! */
751	if (write_flush(ctxt) < 0) {
752	return ctxt->output_rc;
753	}
754	/* Try again with a blocking read. */
755	rblock = APR_BLOCK_READ;
756	continue;
757	}
758
759	rblock = APR_NONBLOCK_READ;
760
761	if (!APR_STATUS_IS_EOF(status)
762	&& (status != APR_SUCCESS)) {
763	return status;
764	}
765
766	if (len > 0) {
767
768	if (ctxt->session == NULL) {
769	ret = GNUTLS_E_INVALID_REQUEST;
770	} else {
771	do {
772	ret =
773	gnutls_record_send
774	(ctxt->session, data,
775	len);
776	} while (ret == GNUTLS_E_INTERRUPTED
777	\|\| ret == GNUTLS_E_AGAIN);
778	}
779
780	if (ret < 0) {
781	/* error sending output */
782	ap_log_cerror(APLOG_MARK, APLOG_INFO, ctxt->output_rc,
783	ctxt->c,
784	"GnuTLS: Error writing data. (%d) '%s'",
785	ret, gnutls_strerror(ret));
786	if (ctxt->output_rc == APR_SUCCESS) {
787	ctxt->output_rc =
788	APR_EGENERAL;
789	return ctxt->output_rc;
790	}
791	} else if ((apr_size_t)(ret) != len) {
792	/* we know the above cast is OK because len > 0 and ret >= 0 */
793	/* Not able to send the entire bucket,
794	split it and send it again. */
795	apr_bucket_split(bucket, ret);
796	}
797	}
798
799	apr_bucket_delete(bucket);
800	}
801	}
802
803	return status;
804	}
805
806	/**
807	* Pull function for GnuTLS
808	*
809	* Generic errnos used for `gnutls_transport_set_errno()`:
810	* * `EAGAIN`: no data available at the moment, try again (maybe later)
811	* * `EINTR`: read was interrupted, try again
812	* * `EIO`: Unknown I/O error
813	* * `ECONNABORTED`: Input BB does not exist (`NULL`)
814	*
815	* The reason we are not using `APR_TO_OS_ERROR` to map `apr_status_t`
816	* to errnos is this warning [in the APR documentation][apr-warn]:
817	*
818	* > If the statcode was not created by apr_get_os_error or
819	* > APR_FROM_OS_ERROR, the results are undefined.
820	*
821	* We cannot know if this applies to any error we might encounter.
822	*
823	* @param ptr GnuTLS session data pointer (the mod_gnutls context
824	* structure)
825	*
826	* @param buffer buffer for the read data
827	*
828	* @param len maximum number of bytes to read (must fit into the
829	* buffer)
830	*
831	* @return The number of bytes read (may be zero on EOF), or `-1` on
832	* error. Note that some errors may warrant another try (see above).
833	*
834	* [apr-warn]: https://apr.apache.org/docs/apr/1.4/group__apr__errno.html#ga2385cae04b04afbdcb65f1a45c4d8506 "Apache Portable Runtime: Error Codes"
835	*/
836	ssize_t mgs_transport_read(gnutls_transport_ptr_t ptr,
837	void *buffer, size_t len)
838	{
839	mgs_handle_t *ctxt = ptr;
840	apr_status_t rc;
841	apr_size_t in = len;
842	apr_read_type_e block = ctxt->input_block;
843
844	ctxt->input_rc = APR_SUCCESS;
845
846	/* If Len = 0, we don't do anything. */
847	if (!len \|\| buffer == NULL)
848	{
849	return 0;
850	}
851	/* Input bucket brigade is missing, EOF */
852	if (!ctxt->input_bb)
853	{
854	ctxt->input_rc = APR_EOF;
855	gnutls_transport_set_errno(ctxt->session, ECONNABORTED);
856	return -1;
857	}
858
859	if (APR_BRIGADE_EMPTY(ctxt->input_bb))
860	{
861	rc = ap_get_brigade(ctxt->input_filter->next,
862	ctxt->input_bb, AP_MODE_READBYTES,
863	ctxt->input_block, in);
864
865	/* Not a problem, there was simply no data ready yet.
866	*/
867	if (APR_STATUS_IS_EAGAIN(rc) \|\| APR_STATUS_IS_EINTR(rc)
868	\|\| (rc == APR_SUCCESS
869	&& APR_BRIGADE_EMPTY(ctxt->input_bb)))
870	{
871	/* Turning APR_SUCCESS into APR_EINTR isn't ideal, but
872	* it's the best matching error code for "didn't get data,
873	* but read didn't permanently fail either." */
874	ctxt->input_rc = (rc != APR_SUCCESS ? rc : APR_EINTR);
875	gnutls_transport_set_errno(ctxt->session,
876	EAI_APR_TO_RAW(ctxt->input_rc));
877	return -1;
878	}
879
880	if (rc != APR_SUCCESS)
881	{
882	/* Unexpected errors discard the brigade */
883	apr_brigade_cleanup(ctxt->input_bb);
884	ctxt->input_bb = NULL;
885	gnutls_transport_set_errno(ctxt->session, EIO);
886	return -1;
887	}
888	}
889
890	ctxt->input_rc = brigade_consume(ctxt->input_bb, block, buffer, &len);
891
892	if (ctxt->input_rc == APR_SUCCESS)
893	{
894	return (ssize_t) len;
895	}
896
897	if (APR_STATUS_IS_EAGAIN(ctxt->input_rc)
898	\|\| APR_STATUS_IS_EINTR(ctxt->input_rc))
899	{
900	if (len == 0)
901	{
902	gnutls_transport_set_errno(ctxt->session,
903	EAI_APR_TO_RAW(ctxt->input_rc));
904	return -1;
905	}
906
907	return (ssize_t) len;
908	}
909
910	/* Unexpected errors and APR_EOF clean out the brigade.
911	* Subsequent calls will return APR_EOF. */
912	apr_brigade_cleanup(ctxt->input_bb);
913	ctxt->input_bb = NULL;
914
915	if (APR_STATUS_IS_EOF(ctxt->input_rc) && len)
916	{
917	/* Some data has been received before EOF, return it. */
918	return (ssize_t) len;
919	}
920
921	gnutls_transport_set_errno(ctxt->session, EIO);
922	return -1;
923	}
924
925	/**
926	* Push function for GnuTLS
927	*
928	* `gnutls_transport_set_errno()` will be called with `EAGAIN` or
929	* `EINTR` on recoverable errors, or `EIO` in case of unexpected
930	* errors. See the description of mgs_transport_read() for details on
931	* possible error codes.
932	*
933	* @param ptr GnuTLS session data pointer (the mod_gnutls context
934	* structure)
935	*
936	* @param buffer buffer containing the data to send
937	*
938	* @param len length of the data
939	* buffer)
940	*
941	* @return The number of written bytes, or `-1` on error. Note that
942	* some errors may warrant another try (see above).
943	*/
944	ssize_t mgs_transport_write(gnutls_transport_ptr_t ptr,
945	const void *buffer, size_t len)
946	{
947	mgs_handle_t *ctxt = ptr;
948
949	/* pass along the encrypted data
950	* need to flush since we're using SSL's malloc-ed buffer
951	* which will be overwritten once we leave here
952	*/
953	apr_bucket *bucket = apr_bucket_transient_create(buffer, len,
954	ctxt->output_bb->
955	bucket_alloc);
956	ctxt->output_length += len;
957	APR_BRIGADE_INSERT_TAIL(ctxt->output_bb, bucket);
958
959	if (write_flush(ctxt) < 0)
960	{
961	/* We encountered an error. APR_EINTR or APR_EAGAIN can be
962	* handled, treat everything else as a generic I/O error. */
963	int err = EIO;
964	if (APR_STATUS_IS_EAGAIN(ctxt->output_rc)
965	\|\| APR_STATUS_IS_EINTR(ctxt->output_rc))
966	err = EAI_APR_TO_RAW(ctxt->output_rc);
967
968	gnutls_transport_set_errno(ctxt->session, err);
969	return -1;
970	}
971	return len;
972	}

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source: mod_gnutls/src/gnutls_io.c @ bd2b48b

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