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/**
* xrdp: A Remote Desktop Protocol server.
*
* Copyright (C) Koichiro Iwao 2017
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Base64 encoder / decoder
*/
#if defined(HAVE_CONFIG_H)
#include <config_ac.h>
#endif
#include "os_calls.h"
#include <openssl/bio.h>
#include <openssl/evp.h>
size_t
base64_decoded_bytes(const char *src)
{
size_t len;
size_t padding;
len = g_strlen(src);
padding = 0;
if (src[len - 1] == '=')
{
padding++;
if (src[len - 2] == '=')
{
padding++;
}
}
return len * 3 / 4 - padding;
}
/*****************************************************************************/
char *
base64_decode(char *dst, const char *src, size_t len)
{
BIO *b64;
BIO *bio;
char *b64str;
size_t estimated_decoded_bytes;
size_t decoded_bytes;
b64str = g_strdup(src);
estimated_decoded_bytes = base64_decoded_bytes(b64str);
dst[estimated_decoded_bytes] = '\0';
b64 = BIO_new(BIO_f_base64());
bio = BIO_new_mem_buf(b64str, len);
bio = BIO_push(b64, bio);
BIO_set_flags(bio, BIO_FLAGS_BASE64_NO_NL);
decoded_bytes = BIO_read(bio , dst, len);
BIO_free_all(bio);
/* if input is corrupt, return empty string */
if (estimated_decoded_bytes != decoded_bytes)
{
g_strncpy(dst, "", sizeof(""));
}
return dst;
}
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