libs/ldap/liblber/encode.c

   1 /* encode.c - ber output encoding routines */
   2 /* $OpenLDAP$ */
   3 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   4  *
   5  * Copyright 1998-2022 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
  71 typedef 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 */
  75 static unsigned char *
  76 ber_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 */
  86 static unsigned char *
  87 ber_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 */
 111 int
 112 ber_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
 169 static int
 170 ber_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
 196 int
 197 ber_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
 209 int
 210 ber_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
 222 int
 223 ber_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
 252 int
 253 ber_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
 265 int
 266 ber_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
 276 int
 277 ber_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
 310 int
 311 ber_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
 325 int
 326 ber_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 */
 349 typedef 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 sequence/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 */
 359 static int
 360 ber_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
 413 int
 414 ber_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
 423 int
 424 ber_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 */
 434 static int
 435 ber_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
 485 int
 486 ber_put_seq( BerElement *ber )
 487 {
 488         return ber_put_seqorset( ber );
 489 }
 490
 491 int
 492 ber_put_set( BerElement *ber )
 493 {
 494         return ber_put_seqorset( ber );
 495 }
 496
 497 /* N tag */
 498 static ber_tag_t lber_int_null = 0;
 499
 500 /* VARARGS */
 501 int
 502 ber_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 }