/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * * SPDX-License-Identifier: curl * ***************************************************************************/ /* Base64 encoding/decoding */ #include "curl_setup.h" #if !defined(CURL_DISABLE_HTTP_AUTH) || defined(USE_SSH) || \ !defined(CURL_DISABLE_LDAP) || \ !defined(CURL_DISABLE_SMTP) || \ !defined(CURL_DISABLE_POP3) || \ !defined(CURL_DISABLE_IMAP) || \ !defined(CURL_DISABLE_DOH) || defined(USE_SSL) #include "urldata.h" /* for the Curl_easy definition */ #include "warnless.h" #include "curl_base64.h" /* The last 2 #include files should be in this order */ #include "curl_memory.h" #include "memdebug.h" /* ---- Base64 Encoding/Decoding Table --- */ /* Padding character string starts at offset 64. */ static const char base64[]= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; /* The Base 64 encoding with a URL and filename safe alphabet, RFC 4648 section 5 */ static const char base64url[]= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"; static const unsigned char decodetable[] = { 62, 255, 255, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 255, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255, 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 }; /* * Curl_base64_decode() * * Given a base64 NUL-terminated string at src, decode it and return a * pointer in *outptr to a newly allocated memory area holding decoded * data. Size of decoded data is returned in variable pointed by outlen. * * Returns CURLE_OK on success, otherwise specific error code. Function * output shall not be considered valid unless CURLE_OK is returned. * * When decoded data length is 0, returns NULL in *outptr. * * @unittest: 1302 */ CURLcode Curl_base64_decode(const char *src, unsigned char **outptr, size_t *outlen) { size_t srclen = 0; size_t padding = 0; size_t i; size_t numQuantums; size_t fullQuantums; size_t rawlen = 0; unsigned char *pos; unsigned char *newstr; unsigned char lookup[256]; *outptr = NULL; *outlen = 0; srclen = strlen(src); /* Check the length of the input string is valid */ if(!srclen || srclen % 4) return CURLE_BAD_CONTENT_ENCODING; /* srclen is at least 4 here */ while(src[srclen - 1 - padding] == '=') { /* count padding characters */ padding++; /* A maximum of two = padding characters is allowed */ if(padding > 2) return CURLE_BAD_CONTENT_ENCODING; } /* Calculate the number of quantums */ numQuantums = srclen / 4; fullQuantums = numQuantums - (padding ? 1 : 0); /* Calculate the size of the decoded string */ rawlen = (numQuantums * 3) - padding; /* Allocate our buffer including room for a null-terminator */ newstr = malloc(rawlen + 1); if(!newstr) return CURLE_OUT_OF_MEMORY; pos = newstr; memset(lookup, 0xff, sizeof(lookup)); memcpy(&lookup['+'], decodetable, sizeof(decodetable)); /* replaces { unsigned char c; const unsigned char *p = (const unsigned char *)base64; for(c = 0; *p; c++, p++) lookup[*p] = c; } */ /* Decode the complete quantums first */ for(i = 0; i < fullQuantums; i++) { unsigned char val; unsigned int x = 0; int j; for(j = 0; j < 4; j++) { val = lookup[(unsigned char)*src++]; if(val == 0xff) /* bad symbol */ goto bad; x = (x << 6) | val; } pos[2] = x & 0xff; pos[1] = (x >> 8) & 0xff; pos[0] = (x >> 16) & 0xff; pos += 3; } if(padding) { /* this means either 8 or 16 bits output */ unsigned char val; unsigned int x = 0; int j; size_t padc = 0; for(j = 0; j < 4; j++) { if(*src == '=') { x <<= 6; src++; if(++padc > padding) /* this is a badly placed '=' symbol! */ goto bad; } else { val = lookup[(unsigned char)*src++]; if(val == 0xff) /* bad symbol */ goto bad; x = (x << 6) | val; } } if(padding == 1) pos[1] = (x >> 8) & 0xff; pos[0] = (x >> 16) & 0xff; pos += 3 - padding; } /* Zero terminate */ *pos = '\0'; /* Return the decoded data */ *outptr = newstr; *outlen = rawlen; return CURLE_OK; bad: free(newstr); return CURLE_BAD_CONTENT_ENCODING; } static CURLcode base64_encode(const char *table64, const char *inputbuff, size_t insize, char **outptr, size_t *outlen) { char *output; char *base64data; const unsigned char *in = (unsigned char *)inputbuff; const char *padstr = &table64[64]; /* Point to padding string. */ *outptr = NULL; *outlen = 0; if(!insize) insize = strlen(inputbuff); #if SIZEOF_SIZE_T == 4 if(insize > UINT_MAX/4) return CURLE_OUT_OF_MEMORY; #endif base64data = output = malloc((insize + 2) / 3 * 4 + 1); if(!output) return CURLE_OUT_OF_MEMORY; while(insize >= 3) { *output++ = table64[ in[0] >> 2 ]; *output++ = table64[ ((in[0] & 0x03) << 4) | (in[1] >> 4) ]; *output++ = table64[ ((in[1] & 0x0F) << 2) | ((in[2] & 0xC0) >> 6) ]; *output++ = table64[ in[2] & 0x3F ]; insize -= 3; in += 3; } if(insize) { /* this is only one or two bytes now */ *output++ = table64[ in[0] >> 2 ]; if(insize == 1) { *output++ = table64[ ((in[0] & 0x03) << 4) ]; if(*padstr) { *output++ = *padstr; *output++ = *padstr; } } else { /* insize == 2 */ *output++ = table64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xF0) >> 4) ]; *output++ = table64[ ((in[1] & 0x0F) << 2) ]; if(*padstr) *output++ = *padstr; } } /* Zero terminate */ *output = '\0'; /* Return the pointer to the new data (allocated memory) */ *outptr = base64data; /* Return the length of the new data */ *outlen = output - base64data; return CURLE_OK; } /* * Curl_base64_encode() * * Given a pointer to an input buffer and an input size, encode it and * return a pointer in *outptr to a newly allocated memory area holding * encoded data. Size of encoded data is returned in variable pointed by * outlen. * * Input length of 0 indicates input buffer holds a NUL-terminated string. * * Returns CURLE_OK on success, otherwise specific error code. Function * output shall not be considered valid unless CURLE_OK is returned. * * @unittest: 1302 */ CURLcode Curl_base64_encode(const char *inputbuff, size_t insize, char **outptr, size_t *outlen) { return base64_encode(base64, inputbuff, insize, outptr, outlen); } /* * Curl_base64url_encode() * * Given a pointer to an input buffer and an input size, encode it and * return a pointer in *outptr to a newly allocated memory area holding * encoded data. Size of encoded data is returned in variable pointed by * outlen. * * Input length of 0 indicates input buffer holds a NUL-terminated string. * * Returns CURLE_OK on success, otherwise specific error code. Function * output shall not be considered valid unless CURLE_OK is returned. * * @unittest: 1302 */ CURLcode Curl_base64url_encode(const char *inputbuff, size_t insize, char **outptr, size_t *outlen) { return base64_encode(base64url, inputbuff, insize, outptr, outlen); } #endif /* no users so disabled */