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https://github.com/SoftEtherVPN/SoftEtherVPN.git
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233e28f38c
Our own implementation works fine, however we should use OpenSSL's one since we already link to the library. Base64Decode() and Base64Encode() return the required buffer size when "dst" is NULL. This allows to efficiently allocate a buffer, without wasting memory or risking an overflow. Base64FromBin() and Base64ToBin() perform all steps, returning a heap-allocated buffer with the data in it.
65 lines
1.3 KiB
C
65 lines
1.3 KiB
C
#include "Encoding.h"
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#include <math.h>
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#include <openssl/evp.h>
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UINT Base64Decode(void *dst, const void *src, const UINT size)
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{
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if (dst == NULL)
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{
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// 4 input bytes = max. 3 output bytes.
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//
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// EVP_DecodeUpdate() ignores:
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// - Leading/trailing whitespace.
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// - Trailing newlines, carriage returns or EOF characters.
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//
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// EVP_DecodeFinal() fails if the input is not divisible by 4.
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return size / 4 * 3;
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}
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// We don't use EVP_DecodeBlock() because it adds padding if the output is not divisible by 3.
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EVP_ENCODE_CTX *ctx = EVP_ENCODE_CTX_new();
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if (ctx == NULL)
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{
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return 0;
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}
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int ret = 0;
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if (EVP_DecodeUpdate(ctx, dst, &ret, src, size) < 0)
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{
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goto FINAL;
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}
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int dummy;
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if (EVP_DecodeFinal(ctx, dst, &dummy) < 0)
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{
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ret = 0;
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}
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FINAL:
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EVP_ENCODE_CTX_free(ctx);
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return ret;
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}
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UINT Base64Encode(void *dst, const void *src, const UINT size)
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{
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if (dst == NULL)
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{
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// 3 input bytes = 4 output bytes.
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// +1 for the NUL terminator.
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//
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// EVP_EncodeBlock() adds padding when the input is not divisible by 3.
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return ceilf((float)size / 3) * 4 + 1;
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}
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const int ret = EVP_EncodeBlock(dst, src, size);
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if (ret > 0)
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{
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// EVP_EncodeBlock() returns the length of the string without the NUL terminator.
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// We, instead, want to return the amount of bytes written into the output buffer.
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return ret + 1;
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}
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return 0;
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}
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