contrib/bind9/lib/isc/base32.c

   1 /*
   2  * Copyright (C) 2008, 2009  Internet Systems Consortium, Inc. ("ISC")
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
   9  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  10  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  11  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  12  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  13  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  14  * PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 /* $Id: base32.c,v 1.3.116.2 2009/01/18 23:47:41 tbox Exp $ */
  18
  19 /*! \file */
  20
  21 #include <config.h>
  22
  23 #include <isc/base32.h>
  24 #include <isc/buffer.h>
  25 #include <isc/lex.h>
  26 #include <isc/region.h>
  27 #include <isc/string.h>
  28 #include <isc/util.h>
  29
  30 #define RETERR(x) do { \
  31         isc_result_t _r = (x); \
  32         if (_r != ISC_R_SUCCESS) \
  33                 return (_r); \
  34         } while (0)
  35
  36
  37 /*@{*/
  38 /*!
  39  * These static functions are also present in lib/dns/rdata.c.  I'm not
  40  * sure where they should go. -- bwelling
  41  */
  42 static isc_result_t
  43 str_totext(const char *source, isc_buffer_t *target);
  44
  45 static isc_result_t
  46 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length);
  47
  48 /*@}*/
  49
  50 static const char base32[] =
  51          "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=abcdefghijklmnopqrstuvwxyz234567";
  52 static const char base32hex[] =
  53         "0123456789ABCDEFGHIJKLMNOPQRSTUV=0123456789abcdefghijklmnopqrstuv";
  54
  55 static isc_result_t
  56 base32_totext(isc_region_t *source, int wordlength, const char *wordbreak,
  57               isc_buffer_t *target, const char base[])
  58 {
  59         char buf[9];
  60         unsigned int loops = 0;
  61
  62         if (wordlength >= 0 && wordlength < 8)
  63                 wordlength = 8;
  64
  65         memset(buf, 0, sizeof(buf));
  66         while (source->length > 0) {
  67                 buf[0] = base[((source->base[0]>>3)&0x1f)];     /* 5 + */
  68                 if (source->length == 1) {
  69                         buf[1] = base[(source->base[0]<<2)&0x1c];
  70                         buf[2] = buf[3] = buf[4] = '=';
  71                         buf[5] = buf[6] = buf[7] = '=';
  72                         RETERR(str_totext(buf, target));
  73                         break;
  74                 }
  75                 buf[1] = base[((source->base[0]<<2)&0x1c)|      /* 3 = 8 */
  76                               ((source->base[1]>>6)&0x03)];     /* 2 + */
  77                 buf[2] = base[((source->base[1]>>1)&0x1f)];     /* 5 + */
  78                 if (source->length == 2) {
  79                         buf[3] = base[(source->base[1]<<4)&0x10];
  80                         buf[4] = buf[5] = buf[6] = buf[7] = '=';
  81                         RETERR(str_totext(buf, target));
  82                         break;
  83                 }
  84                 buf[3] = base[((source->base[1]<<4)&0x10)|      /* 1 = 8 */
  85                               ((source->base[2]>>4)&0x0f)];     /* 4 + */
  86                 if (source->length == 3) {
  87                         buf[4] = base[(source->base[2]<<1)&0x1e];
  88                         buf[5] = buf[6] = buf[7] = '=';
  89                         RETERR(str_totext(buf, target));
  90                         break;
  91                 }
  92                 buf[4] = base[((source->base[2]<<1)&0x1e)|      /* 4 = 8 */
  93                               ((source->base[3]>>7)&0x01)];     /* 1 + */
  94                 buf[5] = base[((source->base[3]>>2)&0x1f)];     /* 5 + */
  95                 if (source->length == 4) {
  96                         buf[6] = base[(source->base[3]<<3)&0x18];
  97                         buf[7] = '=';
  98                         RETERR(str_totext(buf, target));
  99                         break;
 100                 }
 101                 buf[6] = base[((source->base[3]<<3)&0x18)|      /* 2 = 8 */
 102                               ((source->base[4]>>5)&0x07)];     /* 3 + */
 103                 buf[7] = base[source->base[4]&0x1f];            /* 5 = 8 */
 104                 RETERR(str_totext(buf, target));
 105                 isc_region_consume(source, 5);
 106
 107                 loops++;
 108                 if (source->length != 0 && wordlength >= 0 &&
 109                     (int)((loops + 1) * 8) >= wordlength)
 110                 {
 111                         loops = 0;
 112                         RETERR(str_totext(wordbreak, target));
 113                 }
 114         }
 115         return (ISC_R_SUCCESS);
 116 }
 117
 118 isc_result_t
 119 isc_base32_totext(isc_region_t *source, int wordlength,
 120                   const char *wordbreak, isc_buffer_t *target)
 121 {
 122         return (base32_totext(source, wordlength, wordbreak, target, base32));
 123 }
 124
 125 isc_result_t
 126 isc_base32hex_totext(isc_region_t *source, int wordlength,
 127                      const char *wordbreak, isc_buffer_t *target)
 128 {
 129         return (base32_totext(source, wordlength, wordbreak, target,
 130                               base32hex));
 131 }
 132
 133 /*%
 134  * State of a base32 decoding process in progress.
 135  */
 136 typedef struct {
 137         int length;             /*%< Desired length of binary data or -1 */
 138         isc_buffer_t *target;   /*%< Buffer for resulting binary data */
 139         int digits;             /*%< Number of buffered base32 digits */
 140         isc_boolean_t seen_end; /*%< True if "=" end marker seen */
 141         int val[8];
 142         const char *base;       /*%< Which encoding we are using */
 143         int seen_32;            /*%< Number of significant bytes if non zero */
 144 } base32_decode_ctx_t;
 145
 146 static inline void
 147 base32_decode_init(base32_decode_ctx_t *ctx, int length,
 148                    const char base[], isc_buffer_t *target)
 149 {
 150         ctx->digits = 0;
 151         ctx->seen_end = ISC_FALSE;
 152         ctx->seen_32 = 0;
 153         ctx->length = length;
 154         ctx->target = target;
 155         ctx->base = base;
 156 }
 157
 158 static inline isc_result_t
 159 base32_decode_char(base32_decode_ctx_t *ctx, int c) {
 160         char *s;
 161         unsigned int last;
 162
 163         if (ctx->seen_end)
 164                 return (ISC_R_BADBASE32);
 165         if ((s = strchr(ctx->base, c)) == NULL)
 166                 return (ISC_R_BADBASE32);
 167         last = s - ctx->base;
 168         /*
 169          * Handle lower case.
 170          */
 171         if (last > 32)
 172                 last -= 33;
 173         /*
 174          * Check that padding is contiguous.
 175          */
 176         if (last != 32 && ctx->seen_32 != 0)
 177                 return (ISC_R_BADBASE32);
 178         /*
 179          * Check that padding starts at the right place and that
 180          * bits that should be zero are.
 181          * Record how many significant bytes in answer (seen_32).
 182          */
 183         if (last == 32 && ctx->seen_32 == 0)
 184                 switch (ctx->digits) {
 185                 case 0:
 186                 case 1:
 187                         return (ISC_R_BADBASE32);
 188                 case 2:
 189                         if ((ctx->val[1]&0x03) != 0)
 190                                 return (ISC_R_BADBASE32);
 191                         ctx->seen_32 = 1;
 192                         break;
 193                 case 3:
 194                         return (ISC_R_BADBASE32);
 195                 case 4:
 196                         if ((ctx->val[3]&0x0f) != 0)
 197                                 return (ISC_R_BADBASE32);
 198                         ctx->seen_32 = 3;
 199                         break;
 200                 case 5:
 201                         if ((ctx->val[4]&0x01) != 0)
 202                                 return (ISC_R_BADBASE32);
 203                         ctx->seen_32 = 3;
 204                         break;
 205                 case 6:
 206                         return (ISC_R_BADBASE32);
 207                 case 7:
 208                         if ((ctx->val[6]&0x07) != 0)
 209                                 return (ISC_R_BADBASE32);
 210                         ctx->seen_32 = 4;
 211                         break;
 212                 }
 213         /*
 214          * Zero fill pad values.
 215          */
 216         ctx->val[ctx->digits++] = (last == 32) ? 0 : last;
 217
 218         if (ctx->digits == 8) {
 219                 int n = 5;
 220                 unsigned char buf[5];
 221
 222                 if (ctx->seen_32 != 0) {
 223                         ctx->seen_end = ISC_TRUE;
 224                         n = ctx->seen_32;
 225                 }
 226                 buf[0] = (ctx->val[0]<<3)|(ctx->val[1]>>2);
 227                 buf[1] = (ctx->val[1]<<6)|(ctx->val[2]<<1)|(ctx->val[3]>>4);
 228                 buf[2] = (ctx->val[3]<<4)|(ctx->val[4]>>1);
 229                 buf[3] = (ctx->val[4]<<7)|(ctx->val[5]<<2)|(ctx->val[6]>>3);
 230                 buf[4] = (ctx->val[6]<<5)|(ctx->val[7]);
 231                 RETERR(mem_tobuffer(ctx->target, buf, n));
 232                 if (ctx->length >= 0) {
 233                         if (n > ctx->length)
 234                                 return (ISC_R_BADBASE32);
 235                         else
 236                                 ctx->length -= n;
 237                 }
 238                 ctx->digits = 0;
 239         }
 240         return (ISC_R_SUCCESS);
 241 }
 242
 243 static inline isc_result_t
 244 base32_decode_finish(base32_decode_ctx_t *ctx) {
 245         if (ctx->length > 0)
 246                 return (ISC_R_UNEXPECTEDEND);
 247         if (ctx->digits != 0)
 248                 return (ISC_R_BADBASE32);
 249         return (ISC_R_SUCCESS);
 250 }
 251
 252 static isc_result_t
 253 base32_tobuffer(isc_lex_t *lexer, const char base[], isc_buffer_t *target,
 254                 int length)
 255 {
 256         base32_decode_ctx_t ctx;
 257         isc_textregion_t *tr;
 258         isc_token_t token;
 259         isc_boolean_t eol;
 260
 261         base32_decode_init(&ctx, length, base, target);
 262
 263         while (!ctx.seen_end && (ctx.length != 0)) {
 264                 unsigned int i;
 265
 266                 if (length > 0)
 267                         eol = ISC_FALSE;
 268                 else
 269                         eol = ISC_TRUE;
 270                 RETERR(isc_lex_getmastertoken(lexer, &token,
 271                                               isc_tokentype_string, eol));
 272                 if (token.type != isc_tokentype_string)
 273                         break;
 274                 tr = &token.value.as_textregion;
 275                 for (i = 0; i < tr->length; i++)
 276                         RETERR(base32_decode_char(&ctx, tr->base[i]));
 277         }
 278         if (ctx.length < 0 && !ctx.seen_end)
 279                 isc_lex_ungettoken(lexer, &token);
 280         RETERR(base32_decode_finish(&ctx));
 281         return (ISC_R_SUCCESS);
 282 }
 283
 284 isc_result_t
 285 isc_base32_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 286         return (base32_tobuffer(lexer, base32, target, length));
 287 }
 288
 289 isc_result_t
 290 isc_base32hex_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 291         return (base32_tobuffer(lexer, base32hex, target, length));
 292 }
 293
 294 static isc_result_t
 295 base32_decodestring(const char *cstr, const char base[], isc_buffer_t *target) {
 296         base32_decode_ctx_t ctx;
 297
 298         base32_decode_init(&ctx, -1, base, target);
 299         for (;;) {
 300                 int c = *cstr++;
 301                 if (c == '\0')
 302                         break;
 303                 if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
 304                         continue;
 305                 RETERR(base32_decode_char(&ctx, c));
 306         }
 307         RETERR(base32_decode_finish(&ctx));
 308         return (ISC_R_SUCCESS);
 309 }
 310
 311 isc_result_t
 312 isc_base32_decodestring(const char *cstr, isc_buffer_t *target) {
 313         return (base32_decodestring(cstr, base32, target));
 314 }
 315
 316 isc_result_t
 317 isc_base32hex_decodestring(const char *cstr, isc_buffer_t *target) {
 318         return (base32_decodestring(cstr, base32hex, target));
 319 }
 320
 321 static isc_result_t
 322 base32_decoderegion(isc_region_t *source, const char base[], isc_buffer_t *target) {
 323         base32_decode_ctx_t ctx;
 324
 325         base32_decode_init(&ctx, -1, base, target);
 326         while (source->length != 0) {
 327                 int c = *source->base;
 328                 RETERR(base32_decode_char(&ctx, c));
 329                 isc_region_consume(source, 1);
 330         }
 331         RETERR(base32_decode_finish(&ctx));
 332         return (ISC_R_SUCCESS);
 333 }
 334
 335 isc_result_t
 336 isc_base32_decoderegion(isc_region_t *source, isc_buffer_t *target) {
 337         return (base32_decoderegion(source, base32, target));
 338 }
 339
 340 isc_result_t
 341 isc_base32hex_decoderegion(isc_region_t *source, isc_buffer_t *target) {
 342         return (base32_decoderegion(source, base32hex, target));
 343 }
 344
 345 static isc_result_t
 346 str_totext(const char *source, isc_buffer_t *target) {
 347         unsigned int l;
 348         isc_region_t region;
 349
 350         isc_buffer_availableregion(target, &region);
 351         l = strlen(source);
 352
 353         if (l > region.length)
 354                 return (ISC_R_NOSPACE);
 355
 356         memcpy(region.base, source, l);
 357         isc_buffer_add(target, l);
 358         return (ISC_R_SUCCESS);
 359 }
 360
 361 static isc_result_t
 362 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
 363         isc_region_t tr;
 364
 365         isc_buffer_availableregion(target, &tr);
 366         if (length > tr.length)
 367                 return (ISC_R_NOSPACE);
 368         memcpy(tr.base, base, length);
 369         isc_buffer_add(target, length);
 370         return (ISC_R_SUCCESS);
 371 }