mirror of
https://github.com/Dasharo/subhook.git
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Zeex
103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
/* Copyright (c) 2012-2013 Zeex
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <errno.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#if defined _MSC_VER
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#if defined SUBHOOK_X86
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typedef __int32 intptr_t;
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#elif defined SUBHOOK_X86_64
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typedef __int64 intptr_t;
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#endif
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#else
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#include <stdint.h>
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#endif
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#include "subhook.h"
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#include "subhook_private.h"
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#define SUBHOOK_JUMP_SIZE 5
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struct subhook_x86 {
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unsigned char code[SUBHOOK_JUMP_SIZE];
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};
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int subhook_arch_new(struct subhook *hook) {
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if ((hook->arch = malloc(sizeof(struct subhook_x86))) == NULL)
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return -ENOMEM;
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return 0;
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}
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void subhook_arch_free(struct subhook *hook) {
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free(hook->arch);
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}
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SUBHOOK_EXPORT int SUBHOOK_API subhook_install(struct subhook *hook) {
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static const unsigned char jmp = 0xE9;
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void *src, *dst;
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intptr_t offset;
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if (subhook_is_installed(hook))
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return -EINVAL;
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src = subhook_get_src(hook);
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dst = subhook_get_dst(hook);
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subhook_unprotect(src, SUBHOOK_JUMP_SIZE);
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memcpy(((struct subhook_x86 *)hook->arch)->code, src, SUBHOOK_JUMP_SIZE);
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/* E9 - jump near, relative */
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memcpy(src, &jmp, sizeof(jmp));
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/* jump address is relative to next instruction */
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offset = (intptr_t)dst - ((intptr_t)src + SUBHOOK_JUMP_SIZE);
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memcpy((void*)((intptr_t)src + 1), &offset, SUBHOOK_JUMP_SIZE - sizeof(jmp));
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subhook_set_flags(hook, subhook_get_flags(hook) | SUBHOOK_FLAG_INSTALLED);
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return 0;
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}
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SUBHOOK_EXPORT int SUBHOOK_API subhook_remove(struct subhook *hook) {
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if (!subhook_is_installed(hook))
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return -EINVAL;
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memcpy(subhook_get_src(hook), ((struct subhook_x86 *)hook->arch)->code, SUBHOOK_JUMP_SIZE);
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subhook_set_flags(hook, subhook_get_flags(hook) & ~(SUBHOOK_FLAG_INSTALLED));
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return 0;
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}
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SUBHOOK_EXPORT void *SUBHOOK_API subhook_read_dst(void *src) {
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if (*(unsigned char*)src == 0xE9)
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return (void *)(*(intptr_t *)((intptr_t)src + 1) + (intptr_t)src + SUBHOOK_JUMP_SIZE);
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return NULL;
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}
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