/*************************************************************************** * 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 */ /* 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; }