external/bsd/bind/dist/lib/isc/base64.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2004, 2005, 2007, 2009  Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (C) 1998-2001, 2003  Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  17  * PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /* Id: base64.c,v 1.34 2009/10/21 23:48:05 tbox Exp */
  21
  22 /*! \file */
  23
  24 #include <config.h>
  25
  26 #include <isc/base64.h>
  27 #include <isc/buffer.h>
  28 #include <isc/lex.h>
  29 #include <isc/string.h>
  30 #include <isc/util.h>
  31
  32 #define RETERR(x) do { \
  33         isc_result_t _r = (x); \
  34         if (_r != ISC_R_SUCCESS) \
  35                 return (_r); \
  36         } while (0)
  37
  38
  39 /*@{*/
  40 /*!
  41  * These static functions are also present in lib/dns/rdata.c.  I'm not
  42  * sure where they should go. -- bwelling
  43  */
  44 static isc_result_t
  45 str_totext(const char *source, isc_buffer_t *target);
  46
  47 static isc_result_t
  48 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length);
  49
  50 static const char base64[] =
  51         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  52 /*@}*/
  53
  54 isc_result_t
  55 isc_base64_totext(isc_region_t *source, int wordlength,
  56                   const char *wordbreak, isc_buffer_t *target)
  57 {
  58         char buf[5];
  59         unsigned int loops = 0;
  60
  61         if (wordlength < 4)
  62                 wordlength = 4;
  63
  64         memset(buf, 0, sizeof(buf));
  65         while (source->length > 2) {
  66                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  67                 buf[1] = base64[((source->base[0]<<4)&0x30)|
  68                                 ((source->base[1]>>4)&0x0f)];
  69                 buf[2] = base64[((source->base[1]<<2)&0x3c)|
  70                                 ((source->base[2]>>6)&0x03)];
  71                 buf[3] = base64[source->base[2]&0x3f];
  72                 RETERR(str_totext(buf, target));
  73                 isc_region_consume(source, 3);
  74
  75                 loops++;
  76                 if (source->length != 0 &&
  77                     (int)((loops + 1) * 4) >= wordlength)
  78                 {
  79                         loops = 0;
  80                         RETERR(str_totext(wordbreak, target));
  81                 }
  82         }
  83         if (source->length == 2) {
  84                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  85                 buf[1] = base64[((source->base[0]<<4)&0x30)|
  86                                 ((source->base[1]>>4)&0x0f)];
  87                 buf[2] = base64[((source->base[1]<<2)&0x3c)];
  88                 buf[3] = '=';
  89                 RETERR(str_totext(buf, target));
  90                 isc_region_consume(source, 2);
  91         } else if (source->length == 1) {
  92                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  93                 buf[1] = base64[((source->base[0]<<4)&0x30)];
  94                 buf[2] = buf[3] = '=';
  95                 RETERR(str_totext(buf, target));
  96                 isc_region_consume(source, 1);
  97         }
  98         return (ISC_R_SUCCESS);
  99 }
 100
 101 /*%
 102  * State of a base64 decoding process in progress.
 103  */
 104 typedef struct {
 105         int length;             /*%< Desired length of binary data or -1 */
 106         isc_buffer_t *target;   /*%< Buffer for resulting binary data */
 107         int digits;             /*%< Number of buffered base64 digits */
 108         isc_boolean_t seen_end; /*%< True if "=" end marker seen */
 109         int val[4];
 110 } base64_decode_ctx_t;
 111
 112 static inline void
 113 base64_decode_init(base64_decode_ctx_t *ctx, int length, isc_buffer_t *target)
 114 {
 115         ctx->digits = 0;
 116         ctx->seen_end = ISC_FALSE;
 117         ctx->length = length;
 118         ctx->target = target;
 119 }
 120
 121 static inline isc_result_t
 122 base64_decode_char(base64_decode_ctx_t *ctx, int c) {
 123         char *s;
 124
 125         if (ctx->seen_end)
 126                 return (ISC_R_BADBASE64);
 127         if ((s = strchr(base64, c)) == NULL)
 128                 return (ISC_R_BADBASE64);
 129         ctx->val[ctx->digits++] = s - base64;
 130         if (ctx->digits == 4) {
 131                 int n;
 132                 unsigned char buf[3];
 133                 if (ctx->val[0] == 64 || ctx->val[1] == 64)
 134                         return (ISC_R_BADBASE64);
 135                 if (ctx->val[2] == 64 && ctx->val[3] != 64)
 136                         return (ISC_R_BADBASE64);
 137                 /*
 138                  * Check that bits that should be zero are.
 139                  */
 140                 if (ctx->val[2] == 64 && (ctx->val[1] & 0xf) != 0)
 141                         return (ISC_R_BADBASE64);
 142                 /*
 143                  * We don't need to test for ctx->val[2] != 64 as
 144                  * the bottom two bits of 64 are zero.
 145                  */
 146                 if (ctx->val[3] == 64 && (ctx->val[2] & 0x3) != 0)
 147                         return (ISC_R_BADBASE64);
 148                 n = (ctx->val[2] == 64) ? 1 :
 149                         (ctx->val[3] == 64) ? 2 : 3;
 150                 if (n != 3) {
 151                         ctx->seen_end = ISC_TRUE;
 152                         if (ctx->val[2] == 64)
 153                                 ctx->val[2] = 0;
 154                         if (ctx->val[3] == 64)
 155                                 ctx->val[3] = 0;
 156                 }
 157                 buf[0] = (ctx->val[0]<<2)|(ctx->val[1]>>4);
 158                 buf[1] = (ctx->val[1]<<4)|(ctx->val[2]>>2);
 159                 buf[2] = (ctx->val[2]<<6)|(ctx->val[3]);
 160                 RETERR(mem_tobuffer(ctx->target, buf, n));
 161                 if (ctx->length >= 0) {
 162                         if (n > ctx->length)
 163                                 return (ISC_R_BADBASE64);
 164                         else
 165                                 ctx->length -= n;
 166                 }
 167                 ctx->digits = 0;
 168         }
 169         return (ISC_R_SUCCESS);
 170 }
 171
 172 static inline isc_result_t
 173 base64_decode_finish(base64_decode_ctx_t *ctx) {
 174         if (ctx->length > 0)
 175                 return (ISC_R_UNEXPECTEDEND);
 176         if (ctx->digits != 0)
 177                 return (ISC_R_BADBASE64);
 178         return (ISC_R_SUCCESS);
 179 }
 180
 181 isc_result_t
 182 isc_base64_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 183         base64_decode_ctx_t ctx;
 184         isc_textregion_t *tr;
 185         isc_token_t token;
 186         isc_boolean_t eol;
 187
 188         base64_decode_init(&ctx, length, target);
 189
 190         while (!ctx.seen_end && (ctx.length != 0)) {
 191                 unsigned int i;
 192
 193                 if (length > 0)
 194                         eol = ISC_FALSE;
 195                 else
 196                         eol = ISC_TRUE;
 197                 RETERR(isc_lex_getmastertoken(lexer, &token,
 198                                               isc_tokentype_string, eol));
 199                 if (token.type != isc_tokentype_string)
 200                         break;
 201                 tr = &token.value.as_textregion;
 202                 for (i = 0; i < tr->length; i++)
 203                         RETERR(base64_decode_char(&ctx, tr->base[i]));
 204         }
 205         if (ctx.length < 0 && !ctx.seen_end)
 206                 isc_lex_ungettoken(lexer, &token);
 207         RETERR(base64_decode_finish(&ctx));
 208         return (ISC_R_SUCCESS);
 209 }
 210
 211 isc_result_t
 212 isc_base64_decodestring(const char *cstr, isc_buffer_t *target) {
 213         base64_decode_ctx_t ctx;
 214
 215         base64_decode_init(&ctx, -1, target);
 216         for (;;) {
 217                 int c = *cstr++;
 218                 if (c == '\0')
 219                         break;
 220                 if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
 221                         continue;
 222                 RETERR(base64_decode_char(&ctx, c));
 223         }
 224         RETERR(base64_decode_finish(&ctx));
 225         return (ISC_R_SUCCESS);
 226 }
 227
 228 static isc_result_t
 229 str_totext(const char *source, isc_buffer_t *target) {
 230         unsigned int l;
 231         isc_region_t region;
 232
 233         isc_buffer_availableregion(target, &region);
 234         l = strlen(source);
 235
 236         if (l > region.length)
 237                 return (ISC_R_NOSPACE);
 238
 239         memcpy(region.base, source, l);
 240         isc_buffer_add(target, l);
 241         return (ISC_R_SUCCESS);
 242 }
 243
 244 static isc_result_t
 245 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
 246         isc_region_t tr;
 247
 248         isc_buffer_availableregion(target, &tr);
 249         if (length > tr.length)
 250                 return (ISC_R_NOSPACE);
 251         memcpy(tr.base, base, length);
 252         isc_buffer_add(target, length);
 253         return (ISC_R_SUCCESS);
 254 }