100 lines
2.9 KiB
C
100 lines
2.9 KiB
C
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//
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// XOR.h
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// TunnelKit
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//
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// Created by Tejas Mehta on 5/24/22.
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// Copyright (c) 2022 Davide De Rosa. All rights reserved.
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//
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// https://github.com/passepartoutvpn
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//
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// This file is part of TunnelKit.
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//
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// TunnelKit is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// TunnelKit is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with TunnelKit. If not, see <http://www.gnu.org/licenses/>.
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//
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#import <Foundation/Foundation.h>
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#import "XORMethodNative.h"
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static inline void xor_mask(uint8_t *dst, const uint8_t *src, NSData *xorMask, size_t length)
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{
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if (xorMask.length > 0) {
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for (size_t i = 0; i < length; ++i) {
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dst[i] = src[i] ^ ((uint8_t *)(xorMask.bytes))[i % xorMask.length];
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}
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return;
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}
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memcpy(dst, src, length);
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}
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static inline void xor_ptrpos(uint8_t *dst, const uint8_t *src, size_t length)
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{
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for (size_t i = 0; i < length; ++i) {
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dst[i] = src[i] ^ (i + 1);
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}
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}
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static inline void xor_reverse(uint8_t *dst, const uint8_t *src, size_t length)
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{
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size_t start = 1;
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size_t end = length - 1;
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uint8_t temp = 0;
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dst[0] = src[0];
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while (start < end) {
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temp = src[start];
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dst[start] = src[end];
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dst[end] = temp;
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start++;
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end--;
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}
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if (start == end) {
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dst[start] = src[start];
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}
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}
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static inline void xor_memcpy(uint8_t *dst, NSData *src, XORMethodNative method, NSData *mask, BOOL outbound)
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{
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const uint8_t *source = (uint8_t *)src.bytes;
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switch (method) {
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case XORMethodNativeNone:
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memcpy(dst, source, src.length);
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break;
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case XORMethodNativeMask:
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xor_mask(dst, source, mask, src.length);
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break;
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case XORMethodNativePtrPos:
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xor_ptrpos(dst, source, src.length);
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break;
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case XORMethodNativeReverse:
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xor_reverse(dst, source, src.length);
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break;
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case XORMethodNativeObfuscate:
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if (outbound) {
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xor_ptrpos(dst, source, src.length);
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xor_reverse(dst, dst, src.length);
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xor_ptrpos(dst, dst, src.length);
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xor_mask(dst, dst, mask, src.length);
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} else {
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xor_mask(dst, source, mask, src.length);
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xor_ptrpos(dst, dst, src.length);
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xor_reverse(dst, dst, src.length);
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xor_ptrpos(dst, dst, src.length);
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}
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break;
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}
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}
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