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/***************************************************************************
* Copyright (c) 2009-2010 Open Information Security Foundation
* Copyright (c) 2010-2013 Qualys, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - Neither the name of the Qualys, Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***************************************************************************/
/**
* @file
* @author Ivan Ristic <ivanr@webkreator.com>
*/
/* Adapted from the libb64 project (http://sourceforge.net/projects/libb64), which is in public domain. */
#include "bstr.h"
#include "htp_base64.h"
/**
* Decode single base64-encoded character.
*
* @param[in] value_in
* @return decoded character
*/
int htp_base64_decode_single(signed char value_in) {
static const signed char decoding[] = {62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
-1, -1, -1, -2, -1, -1, -1, 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, -1, -1, -1, -1, -1, -1, 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};
static const signed char decoding_size = sizeof (decoding);
value_in -= 43;
if ((value_in < 0) || (value_in > decoding_size - 1)) return -1;
return decoding[(int) value_in];
}
/**
* Initialize base64 decoder.
*
* @param[in] decoder
*/
void htp_base64_decoder_init(htp_base64_decoder *decoder) {
decoder->step = step_a;
decoder->plainchar = 0;
}
/**
* Feed the supplied memory range to the decoder.
*
* @param[in] decoder
* @param[in] _code_in
* @param[in] length_in
* @param[in] _plaintext_out
* @param[in] length_out
* @return how many bytes were placed into plaintext output
*/
int htp_base64_decode(htp_base64_decoder *decoder, const void *_code_in, int length_in, void *_plaintext_out, int length_out) {
const unsigned char *code_in = (const unsigned char *)_code_in;
unsigned char *plaintext_out = (unsigned char *)_plaintext_out;
const unsigned char *codechar = code_in;
unsigned char *plainchar = plaintext_out;
signed char fragment;
if (length_out <= 0) return 0;
*plainchar = decoder->plainchar;
switch (decoder->step) {
while (1) {
case step_a:
do {
if (codechar == code_in + length_in) {
decoder->step = step_a;
decoder->plainchar = *plainchar;
return (int) (plainchar - plaintext_out);
}
fragment = (char) htp_base64_decode_single(*codechar++);
} while (fragment < 0);
*plainchar = (unsigned char) ((fragment & 0x03f) << 2);
/* fall through */
case step_b:
do {
if (codechar == code_in + length_in) {
decoder->step = step_b;
decoder->plainchar = *plainchar;
return (int) (plainchar - plaintext_out);
}
fragment = (char) htp_base64_decode_single(*codechar++);
} while (fragment < 0);
*plainchar++ |= (fragment & 0x030) >> 4;
*plainchar = (unsigned char) ((fragment & 0x00f) << 4);
if (--length_out == 0) {
return (int) (plainchar - plaintext_out);
}
/* fall through */
case step_c:
do {
if (codechar == code_in + length_in) {
decoder->step = step_c;
decoder->plainchar = *plainchar;
return (int) (plainchar - plaintext_out);
}
fragment = (char) htp_base64_decode_single(*codechar++);
} while (fragment < 0);
*plainchar++ |= (fragment & 0x03c) >> 2;
*plainchar = (unsigned char) ((fragment & 0x003) << 6);
if (--length_out == 0) {
return (int) (plainchar - plaintext_out);
}
/* fall through */
case step_d:
do {
if (codechar == code_in + length_in) {
decoder->step = step_d;
decoder->plainchar = *plainchar;
return (int) (plainchar - plaintext_out);
}
fragment = (char) htp_base64_decode_single(*codechar++);
} while (fragment < 0);
*plainchar++ |= (fragment & 0x03f);
if (--length_out == 0) {
return (int) (plainchar - plaintext_out);
}
/* fall through */
}
}
/* control should not reach here */
return plainchar - plaintext_out;
}
/**
* Base64-decode input, given as bstring.
*
* @param[in] input
* @return new base64-decoded bstring
*/
bstr *htp_base64_decode_bstr(bstr *input) {
return htp_base64_decode_mem(bstr_ptr(input), bstr_len(input));
}
/**
* Base64-decode input, given as memory range.
*
* @param[in] data
* @param[in] len
* @return new base64-decoded bstring
*/
bstr *htp_base64_decode_mem(const void *data, size_t len) {
htp_base64_decoder decoder;
bstr *r = NULL;
htp_base64_decoder_init(&decoder);
unsigned char *tmpstr = malloc(len);
if (tmpstr == NULL) return NULL;
int resulting_len = htp_base64_decode(&decoder, data, (int) len, tmpstr, (int) len);
if (resulting_len > 0) {
r = bstr_dup_mem(tmpstr, resulting_len);
}
free(tmpstr);
return r;
}
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