1/* encode.c - ber output encoding routines */
2/* $OpenLDAP$ */
3/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
4 *
5 * Copyright 1998-2011 The OpenLDAP Foundation.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted only as authorized by the OpenLDAP
10 * Public License.
11 *
12 * A copy of this license is available in the file LICENSE in the
13 * top-level directory of the distribution or, alternatively, at
14 * <http://www.OpenLDAP.org/license.html>.
15 */
16/* Portions Copyright (c) 1990 Regents of the University of Michigan.
17 * All rights reserved.
18 *
19 * Redistribution and use in source and binary forms are permitted
20 * provided that this notice is preserved and that due credit is given
21 * to the University of Michigan at Ann Arbor. The name of the University
22 * may not be used to endorse or promote products derived from this
23 * software without specific prior written permission. This software
24 * is provided ``as is'' without express or implied warranty.
25 */
26/* ACKNOWLEDGEMENTS:
27 * This work was originally developed by the University of Michigan
28 * (as part of U-MICH LDAP).
29 */
30
31#include "portable.h"
32
33#include <ctype.h>
34#include <limits.h>
35#include <stdio.h>
36
37#include <ac/stdlib.h>
38
39#include <ac/stdarg.h>
40#include <ac/socket.h>
41#include <ac/string.h>
42
43#include "lber-int.h"
44
45
46#define OCTET_SIZE(type) ((ber_len_t) (sizeof(type)*CHAR_BIT + 7) / 8)
47#define TAGBUF_SIZE OCTET_SIZE(ber_tag_t)
48#define LENBUF_SIZE (1 + OCTET_SIZE(ber_len_t))
49#define HEADER_SIZE (TAGBUF_SIZE + LENBUF_SIZE)
50
51/*
52 * BER element size constrains:
53 *
54 * - We traditionally support a length of max 0xffffffff.  However
55 *   some functions return an int length so that is their max.
56 *   MAXINT_BERSIZE is the max for those functions.
57 *
58 * - MAXINT_BERSIZE must fit in MAXINT_BERSIZE_OCTETS octets.
59 *
60 * - sizeof(ber_elem_size_t) is normally MAXINT_BERSIZE_OCTETS:
61 *   Big enough for MAXINT_BERSIZE, but not more.  (Larger wastes
62 *   space in the working encoding and DER encoding of a sequence
63 *   or set.  Smaller further limits sizes near a sequence/set.)
64 *
65 * ber_len_t is mostly unrelated to this.  Which may be for the best,
66 * since it is also used for lengths of data that are never encoded.
67 */
68#define MAXINT_BERSIZE \
69	(INT_MAX>0xffffffffUL ? (ber_len_t) 0xffffffffUL : INT_MAX-HEADER_SIZE)
70#define MAXINT_BERSIZE_OCTETS 4
71typedef ber_uint_t ber_elem_size_t; /* normally 32 bits */
72
73
74/* Prepend tag to ptr, which points to the end of a tag buffer */
75static unsigned char *
76ber_prepend_tag( unsigned char *ptr, ber_tag_t tag )
77{
78	do {
79		*--ptr = (unsigned char) tag & 0xffU;
80	} while ( (tag >>= 8) != 0 );
81
82	return ptr;
83}
84
85/* Prepend ber length to ptr, which points to the end of a length buffer */
86static unsigned char *
87ber_prepend_len( unsigned char *ptr, ber_len_t len )
88{
89	/*
90	 * short len if it's less than 128 - one byte giving the len,
91	 * with bit 8 0.
92	 * long len otherwise - one byte with bit 8 set, giving the
93	 * length of the length, followed by the length itself.
94	 */
95
96	*--ptr = (unsigned char) len & 0xffU;
97
98	if ( len >= 0x80 ) {
99		unsigned char *endptr = ptr--;
100
101		while ( (len >>= 8) != 0 ) {
102			*ptr-- = (unsigned char) len & 0xffU;
103		}
104		*ptr = (unsigned char) (endptr - ptr) + 0x80U;
105	}
106
107	return ptr;
108}
109
110/* out->bv_len should be the buffer size on input */
111int
112ber_encode_oid( BerValue *in, BerValue *out )
113{
114	unsigned char *der;
115	unsigned long val1, val;
116	int i, j, len;
117	char *ptr, *end, *inend;
118
119	assert( in != NULL );
120	assert( out != NULL );
121
122	if ( !out->bv_val || out->bv_len < in->bv_len/2 )
123		return -1;
124
125	der = (unsigned char *) out->bv_val;
126	ptr = in->bv_val;
127	inend = ptr + in->bv_len;
128
129	/* OIDs start with <0-1>.<0-39> or 2.<any>, DER-encoded 40*val1+val2 */
130	if ( !isdigit( (unsigned char) *ptr )) return -1;
131	val1 = strtoul( ptr, &end, 10 );
132	if ( end == ptr || val1 > 2 ) return -1;
133	if ( *end++ != '.' || !isdigit( (unsigned char) *end )) return -1;
134	val = strtoul( end, &ptr, 10 );
135	if ( ptr == end ) return -1;
136	if ( val > (val1 < 2 ? 39 : LBER_OID_COMPONENT_MAX - 80) ) return -1;
137	val += val1 * 40;
138
139	for (;;) {
140		if ( ptr > inend ) return -1;
141
142		/* Write the OID component little-endian, then reverse it */
143		len = 0;
144		do {
145			der[len++] = (val & 0xff) | 0x80;
146		} while ( (val >>= 7) != 0 );
147		der[0] &= 0x7f;
148		for ( i = 0, j = len; i < --j; i++ ) {
149			unsigned char tmp = der[i];
150			der[i] = der[j];
151			der[j] = tmp;
152		}
153		der += len;
154
155		if ( ptr == inend )
156			break;
157
158		if ( *ptr++ != '.' ) return -1;
159		if ( !isdigit( (unsigned char) *ptr )) return -1;
160		val = strtoul( ptr, &end, 10 );
161		if ( end == ptr || val > LBER_OID_COMPONENT_MAX ) return -1;
162		ptr = end;
163	}
164
165	out->bv_len = (char *)der - out->bv_val;
166	return 0;
167}
168
169static int
170ber_put_int_or_enum(
171	BerElement *ber,
172	ber_int_t num,
173	ber_tag_t tag )
174{
175	ber_uint_t unum;
176	unsigned char sign, data[TAGBUF_SIZE+1 + OCTET_SIZE(ber_int_t)], *ptr;
177
178	sign = 0;
179	unum = num;	/* Bit fiddling should be done with unsigned values */
180	if ( num < 0 ) {
181		sign = 0xffU;
182		unum = ~unum;
183	}
184	for ( ptr = &data[sizeof(data) - 1] ;; unum >>= 8 ) {
185		*ptr-- = (sign ^ (unsigned char) unum) & 0xffU;
186		if ( unum < 0x80 )	/* top bit at *ptr is sign bit */
187			break;
188	}
189
190	*ptr = (unsigned char) (&data[sizeof(data) - 1] - ptr); /* length */
191	ptr = ber_prepend_tag( ptr, tag );
192
193	return ber_write( ber, (char *) ptr, &data[sizeof(data)] - ptr, 0 );
194}
195
196int
197ber_put_enum(
198	BerElement *ber,
199	ber_int_t num,
200	ber_tag_t tag )
201{
202	if ( tag == LBER_DEFAULT ) {
203		tag = LBER_ENUMERATED;
204	}
205
206	return ber_put_int_or_enum( ber, num, tag );
207}
208
209int
210ber_put_int(
211	BerElement *ber,
212	ber_int_t num,
213	ber_tag_t tag )
214{
215	if ( tag == LBER_DEFAULT ) {
216		tag = LBER_INTEGER;
217	}
218
219	return ber_put_int_or_enum( ber, num, tag );
220}
221
222int
223ber_put_ostring(
224	BerElement *ber,
225	LDAP_CONST char *str,
226	ber_len_t len,
227	ber_tag_t tag )
228{
229	int rc;
230	unsigned char header[HEADER_SIZE], *ptr;
231
232	if ( tag == LBER_DEFAULT ) {
233		tag = LBER_OCTETSTRING;
234	}
235
236	if ( len > MAXINT_BERSIZE ) {
237		return -1;
238	}
239
240	ptr = ber_prepend_len( &header[sizeof(header)], len );
241	ptr = ber_prepend_tag( ptr, tag );
242
243	rc = ber_write( ber, (char *) ptr, &header[sizeof(header)] - ptr, 0 );
244	if ( rc >= 0 && ber_write( ber, str, len, 0 ) >= 0 ) {
245		/* length(tag + length + contents) */
246		return rc + (int) len;
247	}
248
249	return -1;
250}
251
252int
253ber_put_berval(
254	BerElement *ber,
255	struct berval *bv,
256	ber_tag_t tag )
257{
258	if( bv == NULL || bv->bv_len == 0 ) {
259		return ber_put_ostring( ber, "", (ber_len_t) 0, tag );
260	}
261
262	return ber_put_ostring( ber, bv->bv_val, bv->bv_len, tag );
263}
264
265int
266ber_put_string(
267	BerElement *ber,
268	LDAP_CONST char *str,
269	ber_tag_t tag )
270{
271	assert( str != NULL );
272
273	return ber_put_ostring( ber, str, strlen( str ), tag );
274}
275
276int
277ber_put_bitstring(
278	BerElement *ber,
279	LDAP_CONST char *str,
280	ber_len_t blen /* in bits */,
281	ber_tag_t tag )
282{
283	int rc;
284	ber_len_t		len;
285	unsigned char	unusedbits, header[HEADER_SIZE + 1], *ptr;
286
287	if ( tag == LBER_DEFAULT ) {
288		tag = LBER_BITSTRING;
289	}
290
291	unusedbits = (unsigned char) -blen & 7;
292	len = blen / 8 + (unusedbits != 0); /* (blen+7)/8 without overflow */
293	if ( len >= MAXINT_BERSIZE ) {
294		return -1;
295	}
296
297	header[sizeof(header) - 1] = unusedbits;
298	ptr = ber_prepend_len( &header[sizeof(header) - 1], len + 1 );
299	ptr = ber_prepend_tag( ptr, tag );
300
301	rc = ber_write( ber, (char *) ptr, &header[sizeof(header)] - ptr, 0 );
302	if ( rc >= 0 && ber_write( ber, str, len, 0 ) >= 0 ) {
303		/* length(tag + length + unused bit count + bitstring) */
304		return rc + (int) len;
305	}
306
307	return -1;
308}
309
310int
311ber_put_null( BerElement *ber, ber_tag_t tag )
312{
313	unsigned char data[TAGBUF_SIZE + 1], *ptr;
314
315	if ( tag == LBER_DEFAULT ) {
316		tag = LBER_NULL;
317	}
318
319	data[sizeof(data) - 1] = 0;			/* length */
320	ptr = ber_prepend_tag( &data[sizeof(data) - 1], tag );
321
322	return ber_write( ber, (char *) ptr, &data[sizeof(data)] - ptr, 0 );
323}
324
325int
326ber_put_boolean(
327	BerElement *ber,
328	ber_int_t boolval,
329	ber_tag_t tag )
330{
331	unsigned char data[TAGBUF_SIZE + 2], *ptr;
332
333	if ( tag == LBER_DEFAULT )
334		tag = LBER_BOOLEAN;
335
336	data[sizeof(data) - 1] = boolval ? 0xff : 0;
337	data[sizeof(data) - 2] = 1;			/* length */
338	ptr = ber_prepend_tag( &data[sizeof(data) - 2], tag );
339
340	return ber_write( ber, (char *) ptr, &data[sizeof(data)] - ptr, 0 );
341}
342
343
344/* Max number of length octets in a sequence or set, normally 5 */
345#define SOS_LENLEN (1 + (sizeof(ber_elem_size_t) > MAXINT_BERSIZE_OCTETS ? \
346		(ber_len_t) sizeof(ber_elem_size_t) : MAXINT_BERSIZE_OCTETS))
347
348/* Header of incomplete sequence or set */
349typedef struct seqorset_header {
350	char xtagbuf[TAGBUF_SIZE + 1];	/* room for tag + len(tag or len) */
351	union {
352		ber_elem_size_t offset;		/* enclosing seqence/set */
353		char padding[SOS_LENLEN-1];	/* for final length encoding */
354	} next_sos;
355#	define SOS_TAG_END(header) ((unsigned char *) &(header).next_sos - 1)
356} Seqorset_header;
357
358/* Start a sequence or set */
359static int
360ber_start_seqorset(
361	BerElement *ber,
362	ber_tag_t tag )
363{
364	/*
365	 * Write the tag and SOS_LENLEN octets reserved for length, to ber.
366	 * For now, length octets = (tag length, previous ber_sos_inner).
367	 *
368	 * Update ber_sos_inner and the write-cursor ber_sos_ptr.  ber_ptr
369	 * will not move until the outermost sequence or set is complete.
370	 */
371
372	Seqorset_header	header;
373	unsigned char	*headptr;
374	ber_len_t		taglen, headlen;
375	char			*dest, **p;
376
377	assert( ber != NULL );
378	assert( LBER_VALID( ber ) );
379
380	if ( ber->ber_sos_ptr == NULL ) {	/* outermost sequence/set? */
381		header.next_sos.offset = 0;
382		p = &ber->ber_ptr;
383	} else {
384		if ( (ber_len_t) -1 > (ber_elem_size_t) -1 ) {
385			if ( ber->ber_sos_inner > (ber_elem_size_t) -1 )
386				return -1;
387		}
388		header.next_sos.offset = ber->ber_sos_inner;
389		p = &ber->ber_sos_ptr;
390	}
391	headptr = ber_prepend_tag( SOS_TAG_END(header), tag );
392	*SOS_TAG_END(header) = taglen = SOS_TAG_END(header) - headptr;
393	headlen = taglen + SOS_LENLEN;
394
395	/* As ber_write(,headptr,headlen,) except update ber_sos_ptr, not *p */
396	if ( headlen > (ber_len_t) (ber->ber_end - *p) ) {
397		if ( ber_realloc( ber, headlen ) != 0 )
398			return -1;
399	}
400	dest = *p;
401	AC_MEMCPY( dest, headptr, headlen );
402	ber->ber_sos_ptr = dest + headlen;
403
404	ber->ber_sos_inner = dest + taglen - ber->ber_buf;
405
406	/*
407	 * Do not return taglen + SOS_LENLEN here - then ber_put_seqorset()
408	 * should return lenlen - SOS_LENLEN + len, which can be < 0.
409	 */
410	return 0;
411}
412
413int
414ber_start_seq( BerElement *ber, ber_tag_t tag )
415{
416	if ( tag == LBER_DEFAULT ) {
417		tag = LBER_SEQUENCE;
418	}
419
420	return ber_start_seqorset( ber, tag );
421}
422
423int
424ber_start_set( BerElement *ber, ber_tag_t tag )
425{
426	if ( tag == LBER_DEFAULT ) {
427		tag = LBER_SET;
428	}
429
430	return ber_start_seqorset( ber, tag );
431}
432
433/* End a sequence or set */
434static int
435ber_put_seqorset( BerElement *ber )
436{
437	Seqorset_header	header;
438	unsigned char	*lenptr;	/* length octets in the sequence/set */
439	ber_len_t		len;		/* length(contents) */
440	ber_len_t		xlen;		/* len + length(length) */
441
442	assert( ber != NULL );
443	assert( LBER_VALID( ber ) );
444
445	if ( ber->ber_sos_ptr == NULL ) return -1;
446
447	lenptr = (unsigned char *) ber->ber_buf + ber->ber_sos_inner;
448	xlen = ber->ber_sos_ptr - (char *) lenptr;
449	if ( xlen > MAXINT_BERSIZE + SOS_LENLEN ) {
450		return -1;
451	}
452
453	/* Extract sequence/set information from length octets */
454	memcpy( SOS_TAG_END(header), lenptr, SOS_LENLEN );
455
456	/* Store length, and close gap of leftover reserved length octets */
457	len = xlen - SOS_LENLEN;
458	if ( !(ber->ber_options & LBER_USE_DER) ) {
459		int i;
460		lenptr[0] = SOS_LENLEN - 1 + 0x80; /* length(length)-1 */
461		for( i = SOS_LENLEN; --i > 0; len >>= 8 ) {
462			lenptr[i] = len & 0xffU;
463		}
464	} else {
465		unsigned char *p = ber_prepend_len( lenptr + SOS_LENLEN, len );
466		ber_len_t unused = p - lenptr;
467		if ( unused != 0 ) {
468			/* length(length) < the reserved SOS_LENLEN bytes */
469			xlen -= unused;
470			AC_MEMCPY( lenptr, p, xlen );
471			ber->ber_sos_ptr = (char *) lenptr + xlen;
472		}
473	}
474
475	ber->ber_sos_inner = header.next_sos.offset;
476	if ( header.next_sos.offset == 0 ) { /* outermost sequence/set? */
477		/* The ber_ptr is at the set/seq start - move it to the end */
478		ber->ber_ptr = ber->ber_sos_ptr;
479		ber->ber_sos_ptr = NULL;
480	}
481
482	return xlen + *SOS_TAG_END(header); /* lenlen + len + taglen */
483}
484
485int
486ber_put_seq( BerElement *ber )
487{
488	return ber_put_seqorset( ber );
489}
490
491int
492ber_put_set( BerElement *ber )
493{
494	return ber_put_seqorset( ber );
495}
496
497/* N tag */
498static ber_tag_t lber_int_null = 0;
499
500/* VARARGS */
501int
502ber_printf( BerElement *ber, LDAP_CONST char *fmt, ... )
503{
504	va_list		ap;
505	char		*s, **ss;
506	struct berval	*bv, **bvp;
507	int		rc;
508	ber_int_t	i;
509	ber_len_t	len;
510
511	assert( ber != NULL );
512	assert( fmt != NULL );
513	assert( LBER_VALID( ber ) );
514
515	va_start( ap, fmt );
516
517	for ( rc = 0; *fmt && rc != -1; fmt++ ) {
518		switch ( *fmt ) {
519		case '!': { /* hook */
520				BEREncodeCallback *f;
521				void *p;
522
523				ber->ber_usertag = 0;
524
525				f = va_arg( ap, BEREncodeCallback * );
526				p = va_arg( ap, void * );
527				rc = (*f)( ber, p );
528
529				if ( ber->ber_usertag ) {
530					goto next;
531				}
532			} break;
533
534		case 'b':	/* boolean */
535			i = va_arg( ap, ber_int_t );
536			rc = ber_put_boolean( ber, i, ber->ber_tag );
537			break;
538
539		case 'i':	/* int */
540			i = va_arg( ap, ber_int_t );
541			rc = ber_put_int( ber, i, ber->ber_tag );
542			break;
543
544		case 'e':	/* enumeration */
545			i = va_arg( ap, ber_int_t );
546			rc = ber_put_enum( ber, i, ber->ber_tag );
547			break;
548
549		case 'n':	/* null */
550			rc = ber_put_null( ber, ber->ber_tag );
551			break;
552
553		case 'N':	/* Debug NULL */
554			rc = 0;
555			if( lber_int_null != 0 ) {
556				/* Insert NULL to ensure peer ignores unknown tags */
557				rc = ber_put_null( ber, lber_int_null );
558			}
559			break;
560
561		case 'o':	/* octet string (non-null terminated) */
562			s = va_arg( ap, char * );
563			len = va_arg( ap, ber_len_t );
564			rc = ber_put_ostring( ber, s, len, ber->ber_tag );
565			break;
566
567		case 'O':	/* berval octet string */
568			bv = va_arg( ap, struct berval * );
569			if( bv == NULL ) break;
570			rc = ber_put_berval( ber, bv, ber->ber_tag );
571			break;
572
573		case 's':	/* string */
574			s = va_arg( ap, char * );
575			rc = ber_put_string( ber, s, ber->ber_tag );
576			break;
577
578		case 'B':	/* bit string */
579		case 'X':	/* bit string (deprecated) */
580			s = va_arg( ap, char * );
581			len = va_arg( ap, ber_len_t );	/* in bits */
582			rc = ber_put_bitstring( ber, s, len, ber->ber_tag );
583			break;
584
585		case 't':	/* tag for the next element */
586			ber->ber_tag = va_arg( ap, ber_tag_t );
587			goto next;
588
589		case 'v':	/* vector of strings */
590			if ( (ss = va_arg( ap, char ** )) == NULL )
591				break;
592			for ( i = 0; ss[i] != NULL; i++ ) {
593				if ( (rc = ber_put_string( ber, ss[i],
594				    ber->ber_tag )) == -1 )
595					break;
596			}
597			break;
598
599		case 'V':	/* sequences of strings + lengths */
600			if ( (bvp = va_arg( ap, struct berval ** )) == NULL )
601				break;
602			for ( i = 0; bvp[i] != NULL; i++ ) {
603				if ( (rc = ber_put_berval( ber, bvp[i],
604				    ber->ber_tag )) == -1 )
605					break;
606			}
607			break;
608
609		case 'W':	/* BerVarray */
610			if ( (bv = va_arg( ap, BerVarray )) == NULL )
611				break;
612			for ( i = 0; bv[i].bv_val != NULL; i++ ) {
613				if ( (rc = ber_put_berval( ber, &bv[i],
614				    ber->ber_tag )) == -1 )
615					break;
616			}
617			break;
618
619		case '{':	/* begin sequence */
620			rc = ber_start_seq( ber, ber->ber_tag );
621			break;
622
623		case '}':	/* end sequence */
624			rc = ber_put_seqorset( ber );
625			break;
626
627		case '[':	/* begin set */
628			rc = ber_start_set( ber, ber->ber_tag );
629			break;
630
631		case ']':	/* end set */
632			rc = ber_put_seqorset( ber );
633			break;
634
635		default:
636			if( ber->ber_debug ) {
637				ber_log_printf( LDAP_DEBUG_ANY, ber->ber_debug,
638					"ber_printf: unknown fmt %c\n", *fmt );
639			}
640			rc = -1;
641			break;
642		}
643
644		ber->ber_tag = LBER_DEFAULT;
645	next:;
646	}
647
648	va_end( ap );
649
650	return rc;
651}
652