170 lines
6.3 KiB
C
170 lines
6.3 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@gmail.com, http://libtom.org
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*/
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#include "tomcrypt.h"
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/**
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@file base64_decode.c
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Compliant base64 code donated by Wayne Scott (wscott@bitmover.com)
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base64 URL Safe variant (RFC 4648 section 5) by Karel Miko
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*/
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#if defined(LTC_BASE64) || defined (LTC_BASE64_URL)
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#if defined(LTC_BASE64)
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static const unsigned char map_base64[256] = {
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
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255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
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7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
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19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255,
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255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
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37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
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49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255 };
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#endif /* LTC_BASE64 */
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#if defined(LTC_BASE64_URL)
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static const unsigned char map_base64url[256] = {
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
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255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
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7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
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19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 63,
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255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
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37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
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49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255 };
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#endif /* LTC_BASE64_URL */
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static int _base64_decode_internal(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen,
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const unsigned char *map, int strict)
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{
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unsigned long t, x, y, z;
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unsigned char c;
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int g;
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LTC_ARGCHK(in != NULL);
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LTC_ARGCHK(out != NULL);
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LTC_ARGCHK(outlen != NULL);
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g = 3;
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for (x = y = z = t = 0; x < inlen; x++) {
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c = map[in[x]&0xFF];
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if (c == 255) {
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if (strict)
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return CRYPT_INVALID_PACKET;
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else
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continue;
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}
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/* the final = symbols are read and used to trim the remaining bytes */
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if (c == 254) {
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c = 0;
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/* prevent g < 0 which would potentially allow an overflow later */
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if (--g < 0) {
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return CRYPT_INVALID_PACKET;
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}
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} else if (g != 3) {
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/* we only allow = to be at the end */
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return CRYPT_INVALID_PACKET;
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}
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t = (t<<6)|c;
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if (++y == 4) {
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if (z + g > *outlen) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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out[z++] = (unsigned char)((t>>16)&255);
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if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
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if (g > 2) out[z++] = (unsigned char)(t&255);
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y = t = 0;
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}
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}
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if (y != 0) {
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if (y == 1 || map != map_base64url || strict == 1) return CRYPT_INVALID_PACKET;
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t = t << (6 * (4 - y));
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if (z + y - 1 > *outlen) return CRYPT_BUFFER_OVERFLOW;
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if (y >= 2) out[z++] = (unsigned char) ((t >> 16) & 255);
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if (y == 3) out[z++] = (unsigned char) ((t >> 8) & 255);
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}
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*outlen = z;
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return CRYPT_OK;
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}
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#if defined(LTC_BASE64)
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/**
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base64 decode a block of memory
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@param in The base64 data to decode
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@param inlen The length of the base64 data
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@param out [out] The destination of the binary decoded data
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@param outlen [in/out] The max size and resulting size of the decoded data
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@param strict Strict[1] or relaxed[0] decoding of the input
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@return CRYPT_OK if successful
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*/
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int base64_decode_ex(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen, int strict)
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{
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return _base64_decode_internal(in, inlen, out, outlen, map_base64, strict);
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}
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#endif /* LTC_BASE64 */
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#if defined(LTC_BASE64_URL)
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/**
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base64 (URL Safe, RFC 4648 section 5) decode a block of memory
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@param in The base64 data to decode
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@param inlen The length of the base64 data
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@param out [out] The destination of the binary decoded data
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@param outlen [in/out] The max size and resulting size of the decoded data
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@param strict Strict[1] or relaxed[0] decoding of the input
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@return CRYPT_OK if successful
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*/
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int base64url_decode_ex(const unsigned char *in, unsigned long inlen,
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unsigned char *out, unsigned long *outlen, int strict)
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{
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return _base64_decode_internal(in, inlen, out, outlen, map_base64url, strict);
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}
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#endif /* LTC_BASE64_URL */
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#endif
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/* $Source$ */
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/* $Revision$ */
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/* $Date$ */
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