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 1.6 2009/10/21 01:22:29 each 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         if (source->length > 0)
 116                 isc_region_consume(source, source->length);
 117         return (ISC_R_SUCCESS);
 118 }
 119
 120 isc_result_t
 121 isc_base32_totext(isc_region_t *source, int wordlength,
 122                   const char *wordbreak, isc_buffer_t *target)
 123 {
 124         return (base32_totext(source, wordlength, wordbreak, target, base32));
 125 }
 126
 127 isc_result_t
 128 isc_base32hex_totext(isc_region_t *source, int wordlength,
 129                      const char *wordbreak, isc_buffer_t *target)
 130 {
 131         return (base32_totext(source, wordlength, wordbreak, target,
 132                               base32hex));
 133 }
 134
 135 /*%
 136  * State of a base32 decoding process in progress.
 137  */
 138 typedef struct {
 139         int length;             /*%< Desired length of binary data or -1 */
 140         isc_buffer_t *target;   /*%< Buffer for resulting binary data */
 141         int digits;             /*%< Number of buffered base32 digits */
 142         isc_boolean_t seen_end; /*%< True if "=" end marker seen */
 143         int val[8];
 144         const char *base;       /*%< Which encoding we are using */
 145         int seen_32;            /*%< Number of significant bytes if non zero */
 146 } base32_decode_ctx_t;
 147
 148 static inline void
 149 base32_decode_init(base32_decode_ctx_t *ctx, int length,
 150                    const char base[], isc_buffer_t *target)
 151 {
 152         ctx->digits = 0;
 153         ctx->seen_end = ISC_FALSE;
 154         ctx->seen_32 = 0;
 155         ctx->length = length;
 156         ctx->target = target;
 157         ctx->base = base;
 158 }
 159
 160 static inline isc_result_t
 161 base32_decode_char(base32_decode_ctx_t *ctx, int c) {
 162         char *s;
 163         unsigned int last;
 164
 165         if (ctx->seen_end)
 166                 return (ISC_R_BADBASE32);
 167         if ((s = strchr(ctx->base, c)) == NULL)
 168                 return (ISC_R_BADBASE32);
 169         last = s - ctx->base;
 170         /*
 171          * Handle lower case.
 172          */
 173         if (last > 32)
 174                 last -= 33;
 175         /*
 176          * Check that padding is contiguous.
 177          */
 178         if (last != 32 && ctx->seen_32 != 0)
 179                 return (ISC_R_BADBASE32);
 180         /*
 181          * Check that padding starts at the right place and that
 182          * bits that should be zero are.
 183          * Record how many significant bytes in answer (seen_32).
 184          */
 185         if (last == 32 && ctx->seen_32 == 0)
 186                 switch (ctx->digits) {
 187                 case 0:
 188                 case 1:
 189                         return (ISC_R_BADBASE32);
 190                 case 2:
 191                         if ((ctx->val[1]&0x03) != 0)
 192                                 return (ISC_R_BADBASE32);
 193                         ctx->seen_32 = 1;
 194                         break;
 195                 case 3:
 196                         return (ISC_R_BADBASE32);
 197                 case 4:
 198                         if ((ctx->val[3]&0x0f) != 0)
 199                                 return (ISC_R_BADBASE32);
 200                         ctx->seen_32 = 3;
 201                         break;
 202                 case 5:
 203                         if ((ctx->val[4]&0x01) != 0)
 204                                 return (ISC_R_BADBASE32);
 205                         ctx->seen_32 = 3;
 206                         break;
 207                 case 6:
 208                         return (ISC_R_BADBASE32);
 209                 case 7:
 210                         if ((ctx->val[6]&0x07) != 0)
 211                                 return (ISC_R_BADBASE32);
 212                         ctx->seen_32 = 4;
 213                         break;
 214                 }
 215         /*
 216          * Zero fill pad values.
 217          */
 218         ctx->val[ctx->digits++] = (last == 32) ? 0 : last;
 219
 220         if (ctx->digits == 8) {
 221                 int n = 5;
 222                 unsigned char buf[5];
 223
 224                 if (ctx->seen_32 != 0) {
 225                         ctx->seen_end = ISC_TRUE;
 226                         n = ctx->seen_32;
 227                 }
 228                 buf[0] = (ctx->val[0]<<3)|(ctx->val[1]>>2);
 229                 buf[1] = (ctx->val[1]<<6)|(ctx->val[2]<<1)|(ctx->val[3]>>4);
 230                 buf[2] = (ctx->val[3]<<4)|(ctx->val[4]>>1);
 231                 buf[3] = (ctx->val[4]<<7)|(ctx->val[5]<<2)|(ctx->val[6]>>3);
 232                 buf[4] = (ctx->val[6]<<5)|(ctx->val[7]);
 233                 RETERR(mem_tobuffer(ctx->target, buf, n));
 234                 if (ctx->length >= 0) {
 235                         if (n > ctx->length)
 236                                 return (ISC_R_BADBASE32);
 237                         else
 238                                 ctx->length -= n;
 239                 }
 240                 ctx->digits = 0;
 241         }
 242         return (ISC_R_SUCCESS);
 243 }
 244
 245 static inline isc_result_t
 246 base32_decode_finish(base32_decode_ctx_t *ctx) {
 247         if (ctx->length > 0)
 248                 return (ISC_R_UNEXPECTEDEND);
 249         if (ctx->digits != 0)
 250                 return (ISC_R_BADBASE32);
 251         return (ISC_R_SUCCESS);
 252 }
 253
 254 static isc_result_t
 255 base32_tobuffer(isc_lex_t *lexer, const char base[], isc_buffer_t *target,
 256                 int length)
 257 {
 258         base32_decode_ctx_t ctx;
 259         isc_textregion_t *tr;
 260         isc_token_t token;
 261         isc_boolean_t eol;
 262
 263         base32_decode_init(&ctx, length, base, target);
 264
 265         while (!ctx.seen_end && (ctx.length != 0)) {
 266                 unsigned int i;
 267
 268                 if (length > 0)
 269                         eol = ISC_FALSE;
 270                 else
 271                         eol = ISC_TRUE;
 272                 RETERR(isc_lex_getmastertoken(lexer, &token,
 273                                               isc_tokentype_string, eol));
 274                 if (token.type != isc_tokentype_string)
 275                         break;
 276                 tr = &token.value.as_textregion;
 277                 for (i = 0; i < tr->length; i++)
 278                         RETERR(base32_decode_char(&ctx, tr->base[i]));
 279         }
 280         if (ctx.length < 0 && !ctx.seen_end)
 281                 isc_lex_ungettoken(lexer, &token);
 282         RETERR(base32_decode_finish(&ctx));
 283         return (ISC_R_SUCCESS);
 284 }
 285
 286 isc_result_t
 287 isc_base32_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 288         return (base32_tobuffer(lexer, base32, target, length));
 289 }
 290
 291 isc_result_t
 292 isc_base32hex_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 293         return (base32_tobuffer(lexer, base32hex, target, length));
 294 }
 295
 296 static isc_result_t
 297 base32_decodestring(const char *cstr, const char base[], isc_buffer_t *target) {
 298         base32_decode_ctx_t ctx;
 299
 300         base32_decode_init(&ctx, -1, base, target);
 301         for (;;) {
 302                 int c = *cstr++;
 303                 if (c == '\0')
 304                         break;
 305                 if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
 306                         continue;
 307                 RETERR(base32_decode_char(&ctx, c));
 308         }
 309         RETERR(base32_decode_finish(&ctx));
 310         return (ISC_R_SUCCESS);
 311 }
 312
 313 isc_result_t
 314 isc_base32_decodestring(const char *cstr, isc_buffer_t *target) {
 315         return (base32_decodestring(cstr, base32, target));
 316 }
 317
 318 isc_result_t
 319 isc_base32hex_decodestring(const char *cstr, isc_buffer_t *target) {
 320         return (base32_decodestring(cstr, base32hex, target));
 321 }
 322
 323 static isc_result_t
 324 base32_decoderegion(isc_region_t *source, const char base[], isc_buffer_t *target) {
 325         base32_decode_ctx_t ctx;
 326
 327         base32_decode_init(&ctx, -1, base, target);
 328         while (source->length != 0) {
 329                 int c = *source->base;
 330                 RETERR(base32_decode_char(&ctx, c));
 331                 isc_region_consume(source, 1);
 332         }
 333         RETERR(base32_decode_finish(&ctx));
 334         return (ISC_R_SUCCESS);
 335 }
 336
 337 isc_result_t
 338 isc_base32_decoderegion(isc_region_t *source, isc_buffer_t *target) {
 339         return (base32_decoderegion(source, base32, target));
 340 }
 341
 342 isc_result_t
 343 isc_base32hex_decoderegion(isc_region_t *source, isc_buffer_t *target) {
 344         return (base32_decoderegion(source, base32hex, target));
 345 }
 346
 347 static isc_result_t
 348 str_totext(const char *source, isc_buffer_t *target) {
 349         unsigned int l;
 350         isc_region_t region;
 351
 352         isc_buffer_availableregion(target, &region);
 353         l = strlen(source);
 354
 355         if (l > region.length)
 356                 return (ISC_R_NOSPACE);
 357
 358         memcpy(region.base, source, l);
 359         isc_buffer_add(target, l);
 360         return (ISC_R_SUCCESS);
 361 }
 362
 363 static isc_result_t
 364 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
 365         isc_region_t tr;
 366
 367         isc_buffer_availableregion(target, &tr);
 368         if (length > tr.length)
 369                 return (ISC_R_NOSPACE);
 370         memcpy(tr.base, base, length);
 371         isc_buffer_add(target, length);
 372         return (ISC_R_SUCCESS);
 373 }