187 lines
4 KiB
C
187 lines
4 KiB
C
/*
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* Base64 encoding/decoding (RFC1341)
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* Copyright (c) 2005, Jouni Malinen <j@w1.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include "includes.h"
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#include "os.h"
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#include "base64.h"
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static const unsigned char base64_table[65] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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/**
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* base64_encode - Base64 encode
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* @src: Data to be encoded
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* @len: Length of the data to be encoded
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* @out_len: Pointer to output length variable, or %NULL if not used
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* Returns: Allocated buffer of out_len bytes of encoded data,
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* or %NULL on failure
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*
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* Caller is responsible for freeing the returned buffer. Returned buffer is
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* nul terminated to make it easier to use as a C string. The nul terminator is
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* not included in out_len.
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*/
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unsigned char * base64_encode(const unsigned char *src, size_t len,
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size_t *out_len)
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{
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unsigned char *out, *pos;
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const unsigned char *end, *in;
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size_t olen;
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int line_len;
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olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
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olen += olen / 72; /* line feeds */
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olen++; /* nul termination */
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out = os_malloc(olen);
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if (out == NULL)
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return NULL;
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end = src + len;
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in = src;
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pos = out;
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line_len = 0;
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while (end - in >= 3) {
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*pos++ = base64_table[in[0] >> 2];
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*pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
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*pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
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*pos++ = base64_table[in[2] & 0x3f];
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in += 3;
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line_len += 4;
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if (line_len >= 72) {
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*pos++ = '\n';
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line_len = 0;
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}
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}
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if (end - in) {
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*pos++ = base64_table[in[0] >> 2];
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if (end - in == 1) {
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*pos++ = base64_table[(in[0] & 0x03) << 4];
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*pos++ = '=';
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} else {
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*pos++ = base64_table[((in[0] & 0x03) << 4) |
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(in[1] >> 4)];
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*pos++ = base64_table[(in[1] & 0x0f) << 2];
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}
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*pos++ = '=';
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line_len += 4;
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}
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if (line_len)
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*pos++ = '\n';
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*pos = '\0';
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if (out_len)
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*out_len = pos - out;
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return out;
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}
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/**
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* base64_decode - Base64 decode
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* @src: Data to be decoded
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* @len: Length of the data to be decoded
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* @out_len: Pointer to output length variable
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* Returns: Allocated buffer of out_len bytes of decoded data,
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* or %NULL on failure
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*
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* Caller is responsible for freeing the returned buffer.
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*/
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unsigned char * base64_decode(const unsigned char *src, size_t len,
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size_t *out_len)
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{
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unsigned char dtable[256], *out, *pos, in[4], block[4], tmp;
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size_t i, count, olen;
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os_memset(dtable, 0x80, 256);
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for (i = 0; i < sizeof(base64_table) - 1; i++)
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dtable[base64_table[i]] = (unsigned char) i;
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dtable['='] = 0;
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count = 0;
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for (i = 0; i < len; i++) {
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if (dtable[src[i]] != 0x80)
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count++;
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}
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if (count == 0 || count % 4)
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return NULL;
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olen = count / 4 * 3;
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pos = out = os_malloc(olen);
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if (out == NULL)
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return NULL;
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count = 0;
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for (i = 0; i < len; i++) {
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tmp = dtable[src[i]];
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if (tmp == 0x80)
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continue;
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in[count] = src[i];
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block[count] = tmp;
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count++;
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if (count == 4) {
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*pos++ = (block[0] << 2) | (block[1] >> 4);
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*pos++ = (block[1] << 4) | (block[2] >> 2);
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*pos++ = (block[2] << 6) | block[3];
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count = 0;
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}
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}
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if (pos > out) {
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if (in[2] == '=')
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pos -= 2;
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else if (in[3] == '=')
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pos--;
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}
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*out_len = pos - out;
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return out;
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}
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#ifdef TEST_MAIN
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int main(int argc, char *argv[])
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{
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FILE *f;
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size_t len, elen;
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unsigned char *buf, *e;
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if (argc != 4) {
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printf("Usage: base64 <encode|decode> <in file> <out file>\n");
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return -1;
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}
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buf = os_readfile(argv[2], &len);
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if (buf == NULL)
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return -1;
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if (strcmp(argv[1], "encode") == 0)
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e = base64_encode(buf, len, &elen);
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else
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e = base64_decode(buf, len, &elen);
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if (e == NULL)
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return -2;
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f = fopen(argv[3], "w");
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if (f == NULL)
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return -3;
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fwrite(e, 1, elen, f);
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fclose(f);
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free(e);
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return 0;
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}
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#endif /* TEST_MAIN */
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