bss_bio.c revision 59191 
1/* crypto/bio/bss_bio.c  -*- Mode: C; c-file-style: "eay" -*- */
2
3/* Special method for a BIO where the other endpoint is also a BIO
4 * of this kind, handled by the same thread (i.e. the "peer" is actually
5 * ourselves, wearing a different hat).
6 * Such "BIO pairs" are mainly for using the SSL library with I/O interfaces
7 * for which no specific BIO method is available.
8 * See ssl/ssltest.c for some hints on how this can be used. */
9
10#ifndef BIO_PAIR_DEBUG
11# undef NDEBUG /* avoid conflicting definitions */
12# define NDEBUG
13#endif
14
15#include <assert.h>
16#include <limits.h>
17#include <stdlib.h>
18#include <string.h>
19
20#include <openssl/bio.h>
21#include <openssl/err.h>
22#include <openssl/err.h>
23#include <openssl/crypto.h>
24
25#include "openssl/e_os.h"
26#ifndef SSIZE_MAX
27# define SSIZE_MAX INT_MAX
28#endif
29
30static int bio_new(BIO *bio);
31static int bio_free(BIO *bio);
32static int bio_read(BIO *bio, char *buf, int size);
33static int bio_write(BIO *bio, char *buf, int num);
34static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
35static int bio_puts(BIO *bio, char *str);
36
37static int bio_make_pair(BIO *bio1, BIO *bio2);
38static void bio_destroy_pair(BIO *bio);
39
40static BIO_METHOD methods_biop =
41{
42	BIO_TYPE_BIO,
43	"BIO pair",
44	bio_write,
45	bio_read,
46	bio_puts,
47	NULL /* no bio_gets */,
48	bio_ctrl,
49	bio_new,
50	bio_free,
51	NULL /* no bio_callback_ctrl */
52};
53
54BIO_METHOD *BIO_s_bio(void)
55	{
56	return &methods_biop;
57	}
58
59struct bio_bio_st
60{
61	BIO *peer;     /* NULL if buf == NULL.
62	                * If peer != NULL, then peer->ptr is also a bio_bio_st,
63	                * and its "peer" member points back to us.
64	                * peer != NULL iff init != 0 in the BIO. */
65
66	/* This is for what we write (i.e. reading uses peer's struct): */
67	int closed;     /* valid iff peer != NULL */
68	size_t len;     /* valid iff buf != NULL; 0 if peer == NULL */
69	size_t offset;  /* valid iff buf != NULL; 0 if len == 0 */
70	size_t size;
71	char *buf;      /* "size" elements (if != NULL) */
72
73	size_t request; /* valid iff peer != NULL; 0 if len != 0,
74	                 * otherwise set by peer to number of bytes
75	                 * it (unsuccessfully) tried to read,
76	                 * never more than buffer space (size-len) warrants. */
77};
78
79static int bio_new(BIO *bio)
80	{
81	struct bio_bio_st *b;
82
83	b = Malloc(sizeof *b);
84	if (b == NULL)
85		return 0;
86
87	b->peer = NULL;
88	b->size = 17*1024; /* enough for one TLS record (just a default) */
89	b->buf = NULL;
90
91	bio->ptr = b;
92	return 1;
93	}
94
95
96static int bio_free(BIO *bio)
97	{
98	struct bio_bio_st *b;
99
100	if (bio == NULL)
101		return 0;
102	b = bio->ptr;
103
104	assert(b != NULL);
105
106	if (b->peer)
107		bio_destroy_pair(bio);
108
109	if (b->buf != NULL)
110		{
111		Free(b->buf);
112		}
113
114	Free(b);
115
116	return 1;
117	}
118
119
120
121static int bio_read(BIO *bio, char *buf, int size_)
122	{
123	size_t size = size_;
124	size_t rest;
125	struct bio_bio_st *b, *peer_b;
126
127	BIO_clear_retry_flags(bio);
128
129	if (!bio->init)
130		return 0;
131
132	b = bio->ptr;
133	assert(b != NULL);
134	assert(b->peer != NULL);
135	peer_b = b->peer->ptr;
136	assert(peer_b != NULL);
137	assert(peer_b->buf != NULL);
138
139	peer_b->request = 0; /* will be set in "retry_read" situation */
140
141	if (buf == NULL || size == 0)
142		return 0;
143
144	if (peer_b->len == 0)
145		{
146		if (peer_b->closed)
147			return 0; /* writer has closed, and no data is left */
148		else
149			{
150			BIO_set_retry_read(bio); /* buffer is empty */
151			if (size <= peer_b->size)
152				peer_b->request = size;
153			else
154				/* don't ask for more than the peer can
155				 * deliver in one write */
156				peer_b->request = peer_b->size;
157			return -1;
158			}
159		}
160
161	/* we can read */
162	if (peer_b->len < size)
163		size = peer_b->len;
164
165	/* now read "size" bytes */
166
167	rest = size;
168
169	assert(rest > 0);
170	do /* one or two iterations */
171		{
172		size_t chunk;
173
174		assert(rest <= peer_b->len);
175		if (peer_b->offset + rest <= peer_b->size)
176			chunk = rest;
177		else
178			/* wrap around ring buffer */
179			chunk = peer_b->size - peer_b->offset;
180		assert(peer_b->offset + chunk <= peer_b->size);
181
182		memcpy(buf, peer_b->buf + peer_b->offset, chunk);
183
184		peer_b->len -= chunk;
185		if (peer_b->len)
186			{
187			peer_b->offset += chunk;
188			assert(peer_b->offset <= peer_b->size);
189			if (peer_b->offset == peer_b->size)
190				peer_b->offset = 0;
191			buf += chunk;
192			}
193		else
194			{
195			/* buffer now empty, no need to advance "buf" */
196			assert(chunk == rest);
197			peer_b->offset = 0;
198			}
199		rest -= chunk;
200		}
201	while (rest);
202
203	return size;
204	}
205
206/* non-copying interface: provide pointer to available data in buffer
207 *    bio_nread0:  return number of available bytes
208 *    bio_nread:   also advance index
209 * (example usage:  bio_nread0(), read from buffer, bio_nread()
210 *  or just         bio_nread(), read from buffer)
211 */
212/* WARNING: The non-copying interface is largely untested as of yet
213 * and may contain bugs. */
214static ssize_t bio_nread0(BIO *bio, char **buf)
215	{
216	struct bio_bio_st *b, *peer_b;
217	ssize_t num;
218
219	BIO_clear_retry_flags(bio);
220
221	if (!bio->init)
222		return 0;
223
224	b = bio->ptr;
225	assert(b != NULL);
226	assert(b->peer != NULL);
227	peer_b = b->peer->ptr;
228	assert(peer_b != NULL);
229	assert(peer_b->buf != NULL);
230
231	peer_b->request = 0;
232
233	if (peer_b->len == 0)
234		{
235		char dummy;
236
237		/* avoid code duplication -- nothing available for reading */
238		return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
239		}
240
241	num = peer_b->len;
242	if (peer_b->size < peer_b->offset + num)
243		/* no ring buffer wrap-around for non-copying interface */
244		num = peer_b->size - peer_b->offset;
245	assert(num > 0);
246
247	if (buf != NULL)
248		*buf = peer_b->buf + peer_b->offset;
249	return num;
250	}
251
252static ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
253	{
254	struct bio_bio_st *b, *peer_b;
255	ssize_t num, available;
256
257	if (num_ > SSIZE_MAX)
258		num = SSIZE_MAX;
259	else
260		num = (ssize_t)num_;
261
262	available = bio_nread0(bio, buf);
263	if (num > available)
264		num = available;
265	if (num <= 0)
266		return num;
267
268	b = bio->ptr;
269	peer_b = b->peer->ptr;
270
271	peer_b->len -= num;
272	if (peer_b->len)
273		{
274		peer_b->offset += num;
275		assert(peer_b->offset <= peer_b->size);
276		if (peer_b->offset == peer_b->size)
277			peer_b->offset = 0;
278		}
279	else
280		peer_b->offset = 0;
281
282	return num;
283	}
284
285
286static int bio_write(BIO *bio, char *buf, int num_)
287	{
288	size_t num = num_;
289	size_t rest;
290	struct bio_bio_st *b;
291
292	BIO_clear_retry_flags(bio);
293
294	if (!bio->init || buf == NULL || num == 0)
295		return 0;
296
297	b = bio->ptr;
298	assert(b != NULL);
299	assert(b->peer != NULL);
300	assert(b->buf != NULL);
301
302	b->request = 0;
303	if (b->closed)
304		{
305		/* we already closed */
306		BIOerr(BIO_F_BIO_WRITE, BIO_R_BROKEN_PIPE);
307		return -1;
308		}
309
310	assert(b->len <= b->size);
311
312	if (b->len == b->size)
313		{
314		BIO_set_retry_write(bio); /* buffer is full */
315		return -1;
316		}
317
318	/* we can write */
319	if (num > b->size - b->len)
320		num = b->size - b->len;
321
322	/* now write "num" bytes */
323
324	rest = num;
325
326	assert(rest > 0);
327	do /* one or two iterations */
328		{
329		size_t write_offset;
330		size_t chunk;
331
332		assert(b->len + rest <= b->size);
333
334		write_offset = b->offset + b->len;
335		if (write_offset >= b->size)
336			write_offset -= b->size;
337		/* b->buf[write_offset] is the first byte we can write to. */
338
339		if (write_offset + rest <= b->size)
340			chunk = rest;
341		else
342			/* wrap around ring buffer */
343			chunk = b->size - write_offset;
344
345		memcpy(b->buf + write_offset, buf, chunk);
346
347		b->len += chunk;
348
349		assert(b->len <= b->size);
350
351		rest -= chunk;
352		buf += chunk;
353		}
354	while (rest);
355
356	return num;
357	}
358
359/* non-copying interface: provide pointer to region to write to
360 *   bio_nwrite0:  check how much space is available
361 *   bio_nwrite:   also increase length
362 * (example usage:  bio_nwrite0(), write to buffer, bio_nwrite()
363 *  or just         bio_nwrite(), write to buffer)
364 */
365static ssize_t bio_nwrite0(BIO *bio, char **buf)
366	{
367	struct bio_bio_st *b;
368	size_t num;
369	size_t write_offset;
370
371	BIO_clear_retry_flags(bio);
372
373	if (!bio->init)
374		return 0;
375
376	b = bio->ptr;
377	assert(b != NULL);
378	assert(b->peer != NULL);
379	assert(b->buf != NULL);
380
381	b->request = 0;
382	if (b->closed)
383		{
384		BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
385		return -1;
386		}
387
388	assert(b->len <= b->size);
389
390	if (b->len == b->size)
391		{
392		BIO_set_retry_write(bio);
393		return -1;
394		}
395
396	num = b->size - b->len;
397	write_offset = b->offset + b->len;
398	if (write_offset >= b->size)
399		write_offset -= b->size;
400	if (write_offset + num > b->size)
401		/* no ring buffer wrap-around for non-copying interface
402		 * (to fulfil the promise by BIO_ctrl_get_write_guarantee,
403		 * BIO_nwrite may have to be called twice) */
404		num = b->size - write_offset;
405
406	if (buf != NULL)
407		*buf = b->buf + write_offset;
408	assert(write_offset + num <= b->size);
409
410	return num;
411	}
412
413static ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
414	{
415	struct bio_bio_st *b;
416	ssize_t num, space;
417
418	if (num_ > SSIZE_MAX)
419		num = SSIZE_MAX;
420	else
421		num = (ssize_t)num_;
422
423	space = bio_nwrite0(bio, buf);
424	if (num > space)
425		num = space;
426	if (num <= 0)
427		return num;
428	b = bio->ptr;
429	assert(b != NULL);
430	b->len += num;
431	assert(b->len <= b->size);
432
433	return num;
434	}
435
436
437static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
438	{
439	long ret;
440	struct bio_bio_st *b = bio->ptr;
441
442	assert(b != NULL);
443
444	switch (cmd)
445		{
446	/* specific CTRL codes */
447
448	case BIO_C_SET_WRITE_BUF_SIZE:
449		if (b->peer)
450			{
451			BIOerr(BIO_F_BIO_CTRL, BIO_R_IN_USE);
452			ret = 0;
453			}
454		else if (num == 0)
455			{
456			BIOerr(BIO_F_BIO_CTRL, BIO_R_INVALID_ARGUMENT);
457			ret = 0;
458			}
459		else
460			{
461			size_t new_size = num;
462
463			if (b->size != new_size)
464				{
465				if (b->buf)
466					{
467					Free(b->buf);
468					b->buf = NULL;
469					}
470				b->size = new_size;
471				}
472			ret = 1;
473			}
474		break;
475
476	case BIO_C_GET_WRITE_BUF_SIZE:
477		num = (long) b->size;
478
479	case BIO_C_MAKE_BIO_PAIR:
480		{
481		BIO *other_bio = ptr;
482
483		if (bio_make_pair(bio, other_bio))
484			ret = 1;
485		else
486			ret = 0;
487		}
488		break;
489
490	case BIO_C_DESTROY_BIO_PAIR:
491		/* Effects both BIOs in the pair -- call just once!
492		 * Or let BIO_free(bio1); BIO_free(bio2); do the job. */
493		bio_destroy_pair(bio);
494		ret = 1;
495		break;
496
497	case BIO_C_GET_WRITE_GUARANTEE:
498		/* How many bytes can the caller feed to the next write
499		 * without having to keep any? */
500		if (b->peer == NULL || b->closed)
501			ret = 0;
502		else
503			ret = (long) b->size - b->len;
504		break;
505
506	case BIO_C_GET_READ_REQUEST:
507		/* If the peer unsuccessfully tried to read, how many bytes
508		 * were requested?  (As with BIO_CTRL_PENDING, that number
509		 * can usually be treated as boolean.) */
510		ret = (long) b->request;
511		break;
512
513	case BIO_C_RESET_READ_REQUEST:
514		/* Reset request.  (Can be useful after read attempts
515		 * at the other side that are meant to be non-blocking,
516		 * e.g. when probing SSL_read to see if any data is
517		 * available.) */
518		b->request = 0;
519		ret = 1;
520		break;
521
522	case BIO_C_SHUTDOWN_WR:
523		/* similar to shutdown(..., SHUT_WR) */
524		b->closed = 1;
525		ret = 1;
526		break;
527
528	case BIO_C_NREAD0:
529		/* prepare for non-copying read */
530		ret = (long) bio_nread0(bio, ptr);
531		break;
532
533	case BIO_C_NREAD:
534		/* non-copying read */
535		ret = (long) bio_nread(bio, ptr, (size_t) num);
536		break;
537
538	case BIO_C_NWRITE0:
539		/* prepare for non-copying write */
540		ret = (long) bio_nwrite0(bio, ptr);
541		break;
542
543	case BIO_C_NWRITE:
544		/* non-copying write */
545		ret = (long) bio_nwrite(bio, ptr, (size_t) num);
546		break;
547
548
549	/* standard CTRL codes follow */
550
551	case BIO_CTRL_RESET:
552		if (b->buf != NULL)
553			{
554			b->len = 0;
555			b->offset = 0;
556			}
557		ret = 0;
558		break;
559
560	case BIO_CTRL_GET_CLOSE:
561		ret = bio->shutdown;
562		break;
563
564	case BIO_CTRL_SET_CLOSE:
565		bio->shutdown = (int) num;
566		ret = 1;
567		break;
568
569	case BIO_CTRL_PENDING:
570		if (b->peer != NULL)
571			{
572			struct bio_bio_st *peer_b = b->peer->ptr;
573
574			ret = (long) peer_b->len;
575			}
576		else
577			ret = 0;
578		break;
579
580	case BIO_CTRL_WPENDING:
581		if (b->buf != NULL)
582			ret = (long) b->len;
583		else
584			ret = 0;
585		break;
586
587	case BIO_CTRL_DUP:
588		/* See BIO_dup_chain for circumstances we have to expect. */
589		{
590		BIO *other_bio = ptr;
591		struct bio_bio_st *other_b;
592
593		assert(other_bio != NULL);
594		other_b = other_bio->ptr;
595		assert(other_b != NULL);
596
597		assert(other_b->buf == NULL); /* other_bio is always fresh */
598
599		other_b->size = b->size;
600		}
601
602		ret = 1;
603		break;
604
605	case BIO_CTRL_FLUSH:
606		ret = 1;
607		break;
608
609	case BIO_CTRL_EOF:
610		{
611		BIO *other_bio = ptr;
612
613		if (other_bio)
614			{
615			struct bio_bio_st *other_b = other_bio->ptr;
616
617			assert(other_b != NULL);
618			ret = other_b->len == 0 && other_b->closed;
619			}
620		else
621			ret = 1;
622		}
623		break;
624
625	default:
626		ret = 0;
627		}
628	return ret;
629	}
630
631static int bio_puts(BIO *bio, char *str)
632	{
633	return bio_write(bio, str, strlen(str));
634	}
635
636
637static int bio_make_pair(BIO *bio1, BIO *bio2)
638	{
639	struct bio_bio_st *b1, *b2;
640
641	assert(bio1 != NULL);
642	assert(bio2 != NULL);
643
644	b1 = bio1->ptr;
645	b2 = bio2->ptr;
646
647	if (b1->peer != NULL || b2->peer != NULL)
648		{
649		BIOerr(BIO_F_BIO_MAKE_PAIR, BIO_R_IN_USE);
650		return 0;
651		}
652
653	if (b1->buf == NULL)
654		{
655		b1->buf = Malloc(b1->size);
656		if (b1->buf == NULL)
657			{
658			BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
659			return 0;
660			}
661		b1->len = 0;
662		b1->offset = 0;
663		}
664
665	if (b2->buf == NULL)
666		{
667		b2->buf = Malloc(b2->size);
668		if (b2->buf == NULL)
669			{
670			BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
671			return 0;
672			}
673		b2->len = 0;
674		b2->offset = 0;
675		}
676
677	b1->peer = bio2;
678	b1->closed = 0;
679	b1->request = 0;
680	b2->peer = bio1;
681	b2->closed = 0;
682	b2->request = 0;
683
684	bio1->init = 1;
685	bio2->init = 1;
686
687	return 1;
688	}
689
690static void bio_destroy_pair(BIO *bio)
691	{
692	struct bio_bio_st *b = bio->ptr;
693
694	if (b != NULL)
695		{
696		BIO *peer_bio = b->peer;
697
698		if (peer_bio != NULL)
699			{
700			struct bio_bio_st *peer_b = peer_bio->ptr;
701
702			assert(peer_b != NULL);
703			assert(peer_b->peer == bio);
704
705			peer_b->peer = NULL;
706			peer_bio->init = 0;
707			assert(peer_b->buf != NULL);
708			peer_b->len = 0;
709			peer_b->offset = 0;
710
711			b->peer = NULL;
712			bio->init = 0;
713			assert(b->buf != NULL);
714			b->len = 0;
715			b->offset = 0;
716			}
717		}
718	}
719
720
721/* Exported convenience functions */
722int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
723	BIO **bio2_p, size_t writebuf2)
724	 {
725	 BIO *bio1 = NULL, *bio2 = NULL;
726	 long r;
727	 int ret = 0;
728
729	 bio1 = BIO_new(BIO_s_bio());
730	 if (bio1 == NULL)
731		 goto err;
732	 bio2 = BIO_new(BIO_s_bio());
733	 if (bio2 == NULL)
734		 goto err;
735
736	 if (writebuf1)
737		 {
738		 r = BIO_set_write_buf_size(bio1, writebuf1);
739		 if (!r)
740			 goto err;
741		 }
742	 if (writebuf2)
743		 {
744		 r = BIO_set_write_buf_size(bio2, writebuf2);
745		 if (!r)
746			 goto err;
747		 }
748
749	 r = BIO_make_bio_pair(bio1, bio2);
750	 if (!r)
751		 goto err;
752	 ret = 1;
753
754 err:
755	 if (ret == 0)
756		 {
757		 if (bio1)
758			 {
759			 BIO_free(bio1);
760			 bio1 = NULL;
761			 }
762		 if (bio2)
763			 {
764			 BIO_free(bio2);
765			 bio2 = NULL;
766			 }
767		 }
768
769	 *bio1_p = bio1;
770	 *bio2_p = bio2;
771	 return ret;
772	 }
773
774size_t BIO_ctrl_get_write_guarantee(BIO *bio)
775	{
776	return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
777	}
778
779size_t BIO_ctrl_get_read_request(BIO *bio)
780	{
781	return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
782	}
783
784int BIO_ctrl_reset_read_request(BIO *bio)
785	{
786	return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
787	}
788
789
790/* BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
791 * (conceivably some other BIOs could allow non-copying reads and writes too.)
792 */
793int BIO_nread0(BIO *bio, char **buf)
794	{
795	long ret;
796
797	if (!bio->init)
798		{
799		BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
800		return -2;
801		}
802
803	ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
804	if (ret > INT_MAX)
805		return INT_MAX;
806	else
807		return (int) ret;
808	}
809
810int BIO_nread(BIO *bio, char **buf, int num)
811	{
812	int ret;
813
814	if (!bio->init)
815		{
816		BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
817		return -2;
818		}
819
820	ret = (int) BIO_ctrl(bio, BIO_C_NREAD, num, buf);
821	if (ret > 0)
822		bio->num_read += ret;
823	return ret;
824	}
825
826int BIO_nwrite0(BIO *bio, char **buf)
827	{
828	long ret;
829
830	if (!bio->init)
831		{
832		BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
833		return -2;
834		}
835
836	ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
837	if (ret > INT_MAX)
838		return INT_MAX;
839	else
840		return (int) ret;
841	}
842
843int BIO_nwrite(BIO *bio, char **buf, int num)
844	{
845	int ret;
846
847	if (!bio->init)
848		{
849		BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
850		return -2;
851		}
852
853	ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
854	if (ret > 0)
855		bio->num_read += ret;
856	return ret;
857	}
858