Annotation of embedaddon/curl/lib/base64.c, revision 1.1

1.1     ! misho       1: /***************************************************************************
        !             2:  *                                  _   _ ____  _
        !             3:  *  Project                     ___| | | |  _ \| |
        !             4:  *                             / __| | | | |_) | |
        !             5:  *                            | (__| |_| |  _ <| |___
        !             6:  *                             \___|\___/|_| \_\_____|
        !             7:  *
        !             8:  * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
        !             9:  *
        !            10:  * This software is licensed as described in the file COPYING, which
        !            11:  * you should have received as part of this distribution. The terms
        !            12:  * are also available at https://curl.haxx.se/docs/copyright.html.
        !            13:  *
        !            14:  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
        !            15:  * copies of the Software, and permit persons to whom the Software is
        !            16:  * furnished to do so, under the terms of the COPYING file.
        !            17:  *
        !            18:  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
        !            19:  * KIND, either express or implied.
        !            20:  *
        !            21:  ***************************************************************************/
        !            22: 
        !            23: /* Base64 encoding/decoding */
        !            24: 
        !            25: #include "curl_setup.h"
        !            26: 
        !            27: #if !defined(CURL_DISABLE_HTTP_AUTH) || defined(USE_SSH) || \
        !            28:   !defined(CURL_DISABLE_LDAP) || \
        !            29:   !defined(CURL_DISABLE_DOH) || defined(USE_SSL)
        !            30: 
        !            31: #include "urldata.h" /* for the Curl_easy definition */
        !            32: #include "warnless.h"
        !            33: #include "curl_base64.h"
        !            34: #include "non-ascii.h"
        !            35: 
        !            36: /* The last 3 #include files should be in this order */
        !            37: #include "curl_printf.h"
        !            38: #include "curl_memory.h"
        !            39: #include "memdebug.h"
        !            40: 
        !            41: /* ---- Base64 Encoding/Decoding Table --- */
        !            42: static const char base64[]=
        !            43:   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
        !            44: 
        !            45: /* The Base 64 encoding with an URL and filename safe alphabet, RFC 4648
        !            46:    section 5 */
        !            47: static const char base64url[]=
        !            48:   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
        !            49: 
        !            50: static size_t decodeQuantum(unsigned char *dest, const char *src)
        !            51: {
        !            52:   size_t padding = 0;
        !            53:   const char *s, *p;
        !            54:   unsigned long i, x = 0;
        !            55: 
        !            56:   for(i = 0, s = src; i < 4; i++, s++) {
        !            57:     if(*s == '=') {
        !            58:       x = (x << 6);
        !            59:       padding++;
        !            60:     }
        !            61:     else {
        !            62:       unsigned long v = 0;
        !            63:       p = base64;
        !            64: 
        !            65:       while(*p && (*p != *s)) {
        !            66:         v++;
        !            67:         p++;
        !            68:       }
        !            69: 
        !            70:       if(*p == *s)
        !            71:         x = (x << 6) + v;
        !            72:       else
        !            73:         return 0;
        !            74:     }
        !            75:   }
        !            76: 
        !            77:   if(padding < 1)
        !            78:     dest[2] = curlx_ultouc(x & 0xFFUL);
        !            79: 
        !            80:   x >>= 8;
        !            81:   if(padding < 2)
        !            82:     dest[1] = curlx_ultouc(x & 0xFFUL);
        !            83: 
        !            84:   x >>= 8;
        !            85:   dest[0] = curlx_ultouc(x & 0xFFUL);
        !            86: 
        !            87:   return 3 - padding;
        !            88: }
        !            89: 
        !            90: /*
        !            91:  * Curl_base64_decode()
        !            92:  *
        !            93:  * Given a base64 NUL-terminated string at src, decode it and return a
        !            94:  * pointer in *outptr to a newly allocated memory area holding decoded
        !            95:  * data. Size of decoded data is returned in variable pointed by outlen.
        !            96:  *
        !            97:  * Returns CURLE_OK on success, otherwise specific error code. Function
        !            98:  * output shall not be considered valid unless CURLE_OK is returned.
        !            99:  *
        !           100:  * When decoded data length is 0, returns NULL in *outptr.
        !           101:  *
        !           102:  * @unittest: 1302
        !           103:  */
        !           104: CURLcode Curl_base64_decode(const char *src,
        !           105:                             unsigned char **outptr, size_t *outlen)
        !           106: {
        !           107:   size_t srclen = 0;
        !           108:   size_t length = 0;
        !           109:   size_t padding = 0;
        !           110:   size_t i;
        !           111:   size_t numQuantums;
        !           112:   size_t rawlen = 0;
        !           113:   unsigned char *pos;
        !           114:   unsigned char *newstr;
        !           115: 
        !           116:   *outptr = NULL;
        !           117:   *outlen = 0;
        !           118:   srclen = strlen(src);
        !           119: 
        !           120:   /* Check the length of the input string is valid */
        !           121:   if(!srclen || srclen % 4)
        !           122:     return CURLE_BAD_CONTENT_ENCODING;
        !           123: 
        !           124:   /* Find the position of any = padding characters */
        !           125:   while((src[length] != '=') && src[length])
        !           126:     length++;
        !           127: 
        !           128:   /* A maximum of two = padding characters is allowed */
        !           129:   if(src[length] == '=') {
        !           130:     padding++;
        !           131:     if(src[length + 1] == '=')
        !           132:       padding++;
        !           133:   }
        !           134: 
        !           135:   /* Check the = padding characters weren't part way through the input */
        !           136:   if(length + padding != srclen)
        !           137:     return CURLE_BAD_CONTENT_ENCODING;
        !           138: 
        !           139:   /* Calculate the number of quantums */
        !           140:   numQuantums = srclen / 4;
        !           141: 
        !           142:   /* Calculate the size of the decoded string */
        !           143:   rawlen = (numQuantums * 3) - padding;
        !           144: 
        !           145:   /* Allocate our buffer including room for a zero terminator */
        !           146:   newstr = malloc(rawlen + 1);
        !           147:   if(!newstr)
        !           148:     return CURLE_OUT_OF_MEMORY;
        !           149: 
        !           150:   pos = newstr;
        !           151: 
        !           152:   /* Decode the quantums */
        !           153:   for(i = 0; i < numQuantums; i++) {
        !           154:     size_t result = decodeQuantum(pos, src);
        !           155:     if(!result) {
        !           156:       free(newstr);
        !           157: 
        !           158:       return CURLE_BAD_CONTENT_ENCODING;
        !           159:     }
        !           160: 
        !           161:     pos += result;
        !           162:     src += 4;
        !           163:   }
        !           164: 
        !           165:   /* Zero terminate */
        !           166:   *pos = '\0';
        !           167: 
        !           168:   /* Return the decoded data */
        !           169:   *outptr = newstr;
        !           170:   *outlen = rawlen;
        !           171: 
        !           172:   return CURLE_OK;
        !           173: }
        !           174: 
        !           175: static CURLcode base64_encode(const char *table64,
        !           176:                               struct Curl_easy *data,
        !           177:                               const char *inputbuff, size_t insize,
        !           178:                               char **outptr, size_t *outlen)
        !           179: {
        !           180:   CURLcode result;
        !           181:   unsigned char ibuf[3];
        !           182:   unsigned char obuf[4];
        !           183:   int i;
        !           184:   int inputparts;
        !           185:   char *output;
        !           186:   char *base64data;
        !           187:   char *convbuf = NULL;
        !           188: 
        !           189:   const char *indata = inputbuff;
        !           190: 
        !           191:   *outptr = NULL;
        !           192:   *outlen = 0;
        !           193: 
        !           194:   if(!insize)
        !           195:     insize = strlen(indata);
        !           196: 
        !           197: #if SIZEOF_SIZE_T == 4
        !           198:   if(insize > UINT_MAX/4)
        !           199:     return CURLE_OUT_OF_MEMORY;
        !           200: #endif
        !           201: 
        !           202:   base64data = output = malloc(insize * 4 / 3 + 4);
        !           203:   if(!output)
        !           204:     return CURLE_OUT_OF_MEMORY;
        !           205: 
        !           206:   /*
        !           207:    * The base64 data needs to be created using the network encoding
        !           208:    * not the host encoding.  And we can't change the actual input
        !           209:    * so we copy it to a buffer, translate it, and use that instead.
        !           210:    */
        !           211:   result = Curl_convert_clone(data, indata, insize, &convbuf);
        !           212:   if(result) {
        !           213:     free(output);
        !           214:     return result;
        !           215:   }
        !           216: 
        !           217:   if(convbuf)
        !           218:     indata = (char *)convbuf;
        !           219: 
        !           220:   while(insize > 0) {
        !           221:     for(i = inputparts = 0; i < 3; i++) {
        !           222:       if(insize > 0) {
        !           223:         inputparts++;
        !           224:         ibuf[i] = (unsigned char) *indata;
        !           225:         indata++;
        !           226:         insize--;
        !           227:       }
        !           228:       else
        !           229:         ibuf[i] = 0;
        !           230:     }
        !           231: 
        !           232:     obuf[0] = (unsigned char)  ((ibuf[0] & 0xFC) >> 2);
        !           233:     obuf[1] = (unsigned char) (((ibuf[0] & 0x03) << 4) | \
        !           234:                                ((ibuf[1] & 0xF0) >> 4));
        !           235:     obuf[2] = (unsigned char) (((ibuf[1] & 0x0F) << 2) | \
        !           236:                                ((ibuf[2] & 0xC0) >> 6));
        !           237:     obuf[3] = (unsigned char)   (ibuf[2] & 0x3F);
        !           238: 
        !           239:     switch(inputparts) {
        !           240:     case 1: /* only one byte read */
        !           241:       msnprintf(output, 5, "%c%c==",
        !           242:                 table64[obuf[0]],
        !           243:                 table64[obuf[1]]);
        !           244:       break;
        !           245: 
        !           246:     case 2: /* two bytes read */
        !           247:       msnprintf(output, 5, "%c%c%c=",
        !           248:                 table64[obuf[0]],
        !           249:                 table64[obuf[1]],
        !           250:                 table64[obuf[2]]);
        !           251:       break;
        !           252: 
        !           253:     default:
        !           254:       msnprintf(output, 5, "%c%c%c%c",
        !           255:                 table64[obuf[0]],
        !           256:                 table64[obuf[1]],
        !           257:                 table64[obuf[2]],
        !           258:                 table64[obuf[3]]);
        !           259:       break;
        !           260:     }
        !           261:     output += 4;
        !           262:   }
        !           263: 
        !           264:   /* Zero terminate */
        !           265:   *output = '\0';
        !           266: 
        !           267:   /* Return the pointer to the new data (allocated memory) */
        !           268:   *outptr = base64data;
        !           269: 
        !           270:   free(convbuf);
        !           271: 
        !           272:   /* Return the length of the new data */
        !           273:   *outlen = strlen(base64data);
        !           274: 
        !           275:   return CURLE_OK;
        !           276: }
        !           277: 
        !           278: /*
        !           279:  * Curl_base64_encode()
        !           280:  *
        !           281:  * Given a pointer to an input buffer and an input size, encode it and
        !           282:  * return a pointer in *outptr to a newly allocated memory area holding
        !           283:  * encoded data. Size of encoded data is returned in variable pointed by
        !           284:  * outlen.
        !           285:  *
        !           286:  * Input length of 0 indicates input buffer holds a NUL-terminated string.
        !           287:  *
        !           288:  * Returns CURLE_OK on success, otherwise specific error code. Function
        !           289:  * output shall not be considered valid unless CURLE_OK is returned.
        !           290:  *
        !           291:  * When encoded data length is 0, returns NULL in *outptr.
        !           292:  *
        !           293:  * @unittest: 1302
        !           294:  */
        !           295: CURLcode Curl_base64_encode(struct Curl_easy *data,
        !           296:                             const char *inputbuff, size_t insize,
        !           297:                             char **outptr, size_t *outlen)
        !           298: {
        !           299:   return base64_encode(base64, data, inputbuff, insize, outptr, outlen);
        !           300: }
        !           301: 
        !           302: /*
        !           303:  * Curl_base64url_encode()
        !           304:  *
        !           305:  * Given a pointer to an input buffer and an input size, encode it and
        !           306:  * return a pointer in *outptr to a newly allocated memory area holding
        !           307:  * encoded data. Size of encoded data is returned in variable pointed by
        !           308:  * outlen.
        !           309:  *
        !           310:  * Input length of 0 indicates input buffer holds a NUL-terminated string.
        !           311:  *
        !           312:  * Returns CURLE_OK on success, otherwise specific error code. Function
        !           313:  * output shall not be considered valid unless CURLE_OK is returned.
        !           314:  *
        !           315:  * When encoded data length is 0, returns NULL in *outptr.
        !           316:  *
        !           317:  * @unittest: 1302
        !           318:  */
        !           319: CURLcode Curl_base64url_encode(struct Curl_easy *data,
        !           320:                                const char *inputbuff, size_t insize,
        !           321:                                char **outptr, size_t *outlen)
        !           322: {
        !           323:   return base64_encode(base64url, data, inputbuff, insize, outptr, outlen);
        !           324: }
        !           325: 
        !           326: #endif /* no users so disabled */

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