contrib/bind/lib/isc/base64.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1998-2001, 2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: base64.c,v 1.32 2007/06/19 23:47:17 tbox Exp $ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <isc/base64.h>
  25 #include <isc/buffer.h>
  26 #include <isc/lex.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 static const char base64[] =
  49         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  50 /*@}*/
  51
  52 isc_result_t
  53 isc_base64_totext(isc_region_t *source, int wordlength,
  54                   const char *wordbreak, isc_buffer_t *target)
  55 {
  56         char buf[5];
  57         unsigned int loops = 0;
  58
  59         if (wordlength < 4)
  60                 wordlength = 4;
  61
  62         memset(buf, 0, sizeof(buf));
  63         while (source->length > 2) {
  64                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  65                 buf[1] = base64[((source->base[0]<<4)&0x30)|
  66                                 ((source->base[1]>>4)&0x0f)];
  67                 buf[2] = base64[((source->base[1]<<2)&0x3c)|
  68                                 ((source->base[2]>>6)&0x03)];
  69                 buf[3] = base64[source->base[2]&0x3f];
  70                 RETERR(str_totext(buf, target));
  71                 isc_region_consume(source, 3);
  72
  73                 loops++;
  74                 if (source->length != 0 &&
  75                     (int)((loops + 1) * 4) >= wordlength)
  76                 {
  77                         loops = 0;
  78                         RETERR(str_totext(wordbreak, target));
  79                 }
  80         }
  81         if (source->length == 2) {
  82                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  83                 buf[1] = base64[((source->base[0]<<4)&0x30)|
  84                                 ((source->base[1]>>4)&0x0f)];
  85                 buf[2] = base64[((source->base[1]<<2)&0x3c)];
  86                 buf[3] = '=';
  87                 RETERR(str_totext(buf, target));
  88         } else if (source->length == 1) {
  89                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  90                 buf[1] = base64[((source->base[0]<<4)&0x30)];
  91                 buf[2] = buf[3] = '=';
  92                 RETERR(str_totext(buf, target));
  93         }
  94         return (ISC_R_SUCCESS);
  95 }
  96
  97 /*%
  98  * State of a base64 decoding process in progress.
  99  */
 100 typedef struct {
 101         int length;             /*%< Desired length of binary data or -1 */
 102         isc_buffer_t *target;   /*%< Buffer for resulting binary data */
 103         int digits;             /*%< Number of buffered base64 digits */
 104         isc_boolean_t seen_end; /*%< True if "=" end marker seen */
 105         int val[4];
 106 } base64_decode_ctx_t;
 107
 108 static inline void
 109 base64_decode_init(base64_decode_ctx_t *ctx, int length, isc_buffer_t *target)
 110 {
 111         ctx->digits = 0;
 112         ctx->seen_end = ISC_FALSE;
 113         ctx->length = length;
 114         ctx->target = target;
 115 }
 116
 117 static inline isc_result_t
 118 base64_decode_char(base64_decode_ctx_t *ctx, int c) {
 119         char *s;
 120
 121         if (ctx->seen_end)
 122                 return (ISC_R_BADBASE64);
 123         if ((s = strchr(base64, c)) == NULL)
 124                 return (ISC_R_BADBASE64);
 125         ctx->val[ctx->digits++] = s - base64;
 126         if (ctx->digits == 4) {
 127                 int n;
 128                 unsigned char buf[3];
 129                 if (ctx->val[0] == 64 || ctx->val[1] == 64)
 130                         return (ISC_R_BADBASE64);
 131                 if (ctx->val[2] == 64 && ctx->val[3] != 64)
 132                         return (ISC_R_BADBASE64);
 133                 /*
 134                  * Check that bits that should be zero are.
 135                  */
 136                 if (ctx->val[2] == 64 && (ctx->val[1] & 0xf) != 0)
 137                         return (ISC_R_BADBASE64);
 138                 /*
 139                  * We don't need to test for ctx->val[2] != 64 as
 140                  * the bottom two bits of 64 are zero.
 141                  */
 142                 if (ctx->val[3] == 64 && (ctx->val[2] & 0x3) != 0)
 143                         return (ISC_R_BADBASE64);
 144                 n = (ctx->val[2] == 64) ? 1 :
 145                         (ctx->val[3] == 64) ? 2 : 3;
 146                 if (n != 3) {
 147                         ctx->seen_end = ISC_TRUE;
 148                         if (ctx->val[2] == 64)
 149                                 ctx->val[2] = 0;
 150                         if (ctx->val[3] == 64)
 151                                 ctx->val[3] = 0;
 152                 }
 153                 buf[0] = (ctx->val[0]<<2)|(ctx->val[1]>>4);
 154                 buf[1] = (ctx->val[1]<<4)|(ctx->val[2]>>2);
 155                 buf[2] = (ctx->val[2]<<6)|(ctx->val[3]);
 156                 RETERR(mem_tobuffer(ctx->target, buf, n));
 157                 if (ctx->length >= 0) {
 158                         if (n > ctx->length)
 159                                 return (ISC_R_BADBASE64);
 160                         else
 161                                 ctx->length -= n;
 162                 }
 163                 ctx->digits = 0;
 164         }
 165         return (ISC_R_SUCCESS);
 166 }
 167
 168 static inline isc_result_t
 169 base64_decode_finish(base64_decode_ctx_t *ctx) {
 170         if (ctx->length > 0)
 171                 return (ISC_R_UNEXPECTEDEND);
 172         if (ctx->digits != 0)
 173                 return (ISC_R_BADBASE64);
 174         return (ISC_R_SUCCESS);
 175 }
 176
 177 isc_result_t
 178 isc_base64_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 179         base64_decode_ctx_t ctx;
 180         isc_textregion_t *tr;
 181         isc_token_t token;
 182         isc_boolean_t eol;
 183
 184         base64_decode_init(&ctx, length, target);
 185
 186         while (!ctx.seen_end && (ctx.length != 0)) {
 187                 unsigned int i;
 188
 189                 if (length > 0)
 190                         eol = ISC_FALSE;
 191                 else
 192                         eol = ISC_TRUE;
 193                 RETERR(isc_lex_getmastertoken(lexer, &token,
 194                                               isc_tokentype_string, eol));
 195                 if (token.type != isc_tokentype_string)
 196                         break;
 197                 tr = &token.value.as_textregion;
 198                 for (i = 0; i < tr->length; i++)
 199                         RETERR(base64_decode_char(&ctx, tr->base[i]));
 200         }
 201         if (ctx.length < 0 && !ctx.seen_end)
 202                 isc_lex_ungettoken(lexer, &token);
 203         RETERR(base64_decode_finish(&ctx));
 204         return (ISC_R_SUCCESS);
 205 }
 206
 207 isc_result_t
 208 isc_base64_decodestring(const char *cstr, isc_buffer_t *target) {
 209         base64_decode_ctx_t ctx;
 210
 211         base64_decode_init(&ctx, -1, target);
 212         for (;;) {
 213                 int c = *cstr++;
 214                 if (c == '\0')
 215                         break;
 216                 if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
 217                         continue;
 218                 RETERR(base64_decode_char(&ctx, c));
 219         }
 220         RETERR(base64_decode_finish(&ctx));
 221         return (ISC_R_SUCCESS);
 222 }
 223
 224 static isc_result_t
 225 str_totext(const char *source, isc_buffer_t *target) {
 226         unsigned int l;
 227         isc_region_t region;
 228
 229         isc_buffer_availableregion(target, &region);
 230         l = strlen(source);
 231
 232         if (l > region.length)
 233                 return (ISC_R_NOSPACE);
 234
 235         memcpy(region.base, source, l);
 236         isc_buffer_add(target, l);
 237         return (ISC_R_SUCCESS);
 238 }
 239
 240 static isc_result_t
 241 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
 242         isc_region_t tr;
 243
 244         isc_buffer_availableregion(target, &tr);
 245         if (length > tr.length)
 246                 return (ISC_R_NOSPACE);
 247         memcpy(tr.base, base, length);
 248         isc_buffer_add(target, length);
 249         return (ISC_R_SUCCESS);
 250 }