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

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2004, 2005, 2007  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 1.32 2007/06/19 23:47:17 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         } else if (source->length == 1) {
  91                 buf[0] = base64[(source->base[0]>>2)&0x3f];
  92                 buf[1] = base64[((source->base[0]<<4)&0x30)];
  93                 buf[2] = buf[3] = '=';
  94                 RETERR(str_totext(buf, target));
  95         }
  96         return (ISC_R_SUCCESS);
  97 }
  98
  99 /*%
 100  * State of a base64 decoding process in progress.
 101  */
 102 typedef struct {
 103         int length;             /*%< Desired length of binary data or -1 */
 104         isc_buffer_t *target;   /*%< Buffer for resulting binary data */
 105         int digits;             /*%< Number of buffered base64 digits */
 106         isc_boolean_t seen_end; /*%< True if "=" end marker seen */
 107         int val[4];
 108 } base64_decode_ctx_t;
 109
 110 static inline void
 111 base64_decode_init(base64_decode_ctx_t *ctx, int length, isc_buffer_t *target)
 112 {
 113         ctx->digits = 0;
 114         ctx->seen_end = ISC_FALSE;
 115         ctx->length = length;
 116         ctx->target = target;
 117 }
 118
 119 static inline isc_result_t
 120 base64_decode_char(base64_decode_ctx_t *ctx, int c) {
 121         char *s;
 122
 123         if (ctx->seen_end)
 124                 return (ISC_R_BADBASE64);
 125         if ((s = strchr(base64, c)) == NULL)
 126                 return (ISC_R_BADBASE64);
 127         ctx->val[ctx->digits++] = s - base64;
 128         if (ctx->digits == 4) {
 129                 int n;
 130                 unsigned char buf[3];
 131                 if (ctx->val[0] == 64 || ctx->val[1] == 64)
 132                         return (ISC_R_BADBASE64);
 133                 if (ctx->val[2] == 64 && ctx->val[3] != 64)
 134                         return (ISC_R_BADBASE64);
 135                 /*
 136                  * Check that bits that should be zero are.
 137                  */
 138                 if (ctx->val[2] == 64 && (ctx->val[1] & 0xf) != 0)
 139                         return (ISC_R_BADBASE64);
 140                 /*
 141                  * We don't need to test for ctx->val[2] != 64 as
 142                  * the bottom two bits of 64 are zero.
 143                  */
 144                 if (ctx->val[3] == 64 && (ctx->val[2] & 0x3) != 0)
 145                         return (ISC_R_BADBASE64);
 146                 n = (ctx->val[2] == 64) ? 1 :
 147                         (ctx->val[3] == 64) ? 2 : 3;
 148                 if (n != 3) {
 149                         ctx->seen_end = ISC_TRUE;
 150                         if (ctx->val[2] == 64)
 151                                 ctx->val[2] = 0;
 152                         if (ctx->val[3] == 64)
 153                                 ctx->val[3] = 0;
 154                 }
 155                 buf[0] = (ctx->val[0]<<2)|(ctx->val[1]>>4);
 156                 buf[1] = (ctx->val[1]<<4)|(ctx->val[2]>>2);
 157                 buf[2] = (ctx->val[2]<<6)|(ctx->val[3]);
 158                 RETERR(mem_tobuffer(ctx->target, buf, n));
 159                 if (ctx->length >= 0) {
 160                         if (n > ctx->length)
 161                                 return (ISC_R_BADBASE64);
 162                         else
 163                                 ctx->length -= n;
 164                 }
 165                 ctx->digits = 0;
 166         }
 167         return (ISC_R_SUCCESS);
 168 }
 169
 170 static inline isc_result_t
 171 base64_decode_finish(base64_decode_ctx_t *ctx) {
 172         if (ctx->length > 0)
 173                 return (ISC_R_UNEXPECTEDEND);
 174         if (ctx->digits != 0)
 175                 return (ISC_R_BADBASE64);
 176         return (ISC_R_SUCCESS);
 177 }
 178
 179 isc_result_t
 180 isc_base64_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
 181         base64_decode_ctx_t ctx;
 182         isc_textregion_t *tr;
 183         isc_token_t token;
 184         isc_boolean_t eol;
 185
 186         base64_decode_init(&ctx, length, target);
 187
 188         while (!ctx.seen_end && (ctx.length != 0)) {
 189                 unsigned int i;
 190
 191                 if (length > 0)
 192                         eol = ISC_FALSE;
 193                 else
 194                         eol = ISC_TRUE;
 195                 RETERR(isc_lex_getmastertoken(lexer, &token,
 196                                               isc_tokentype_string, eol));
 197                 if (token.type != isc_tokentype_string)
 198                         break;
 199                 tr = &token.value.as_textregion;
 200                 for (i = 0; i < tr->length; i++)
 201                         RETERR(base64_decode_char(&ctx, tr->base[i]));
 202         }
 203         if (ctx.length < 0 && !ctx.seen_end)
 204                 isc_lex_ungettoken(lexer, &token);
 205         RETERR(base64_decode_finish(&ctx));
 206         return (ISC_R_SUCCESS);
 207 }
 208
 209 isc_result_t
 210 isc_base64_decodestring(const char *cstr, isc_buffer_t *target) {
 211         base64_decode_ctx_t ctx;
 212
 213         base64_decode_init(&ctx, -1, target);
 214         for (;;) {
 215                 int c = *cstr++;
 216                 if (c == '\0')
 217                         break;
 218                 if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
 219                         continue;
 220                 RETERR(base64_decode_char(&ctx, c));
 221         }
 222         RETERR(base64_decode_finish(&ctx));
 223         return (ISC_R_SUCCESS);
 224 }
 225
 226 static isc_result_t
 227 str_totext(const char *source, isc_buffer_t *target) {
 228         unsigned int l;
 229         isc_region_t region;
 230
 231         isc_buffer_availableregion(target, &region);
 232         l = strlen(source);
 233
 234         if (l > region.length)
 235                 return (ISC_R_NOSPACE);
 236
 237         memcpy(region.base, source, l);
 238         isc_buffer_add(target, l);
 239         return (ISC_R_SUCCESS);
 240 }
 241
 242 static isc_result_t
 243 mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
 244         isc_region_t tr;
 245
 246         isc_buffer_availableregion(target, &tr);
 247         if (length > tr.length)
 248                 return (ISC_R_NOSPACE);
 249         memcpy(tr.base, base, length);
 250         isc_buffer_add(target, length);
 251         return (ISC_R_SUCCESS);
 252 }