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Diffstat (limited to '')
| -rw-r--r-- | htp/htp_base64.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/htp/htp_base64.c b/htp/htp_base64.c new file mode 100644 index 0000000..75dc122 --- /dev/null +++ b/htp/htp_base64.c @@ -0,0 +1,196 @@ +/*************************************************************************** + * 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; +} |