https://github.com/ac3ss0r/cvm.h
CVM is a header-only turing-complete virtual machine engine made in pure C.
https://github.com/ac3ss0r/cvm.h
code-virtualizer obfuscation virtualization vm vmprotect
Last synced: 10 months ago
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CVM is a header-only turing-complete virtual machine engine made in pure C.
- Host: GitHub
- URL: https://github.com/ac3ss0r/cvm.h
- Owner: ac3ss0r
- License: apache-2.0
- Created: 2024-08-15T14:13:25.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-11-25T15:46:13.000Z (about 1 year ago)
- Last Synced: 2025-03-27T16:39:58.475Z (10 months ago)
- Topics: code-virtualizer, obfuscation, virtualization, vm, vmprotect
- Language: C
- Homepage:
- Size: 39.1 KB
- Stars: 17
- Watchers: 2
- Forks: 3
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# CVM
CVM is a header-only turing-complete virtual machine engine made in pure C and based on x86-64. It's not fully replicating the architecture, but can be used to implement any existing algorithm. It's created as an example of a VM for code protection purposes.
⚠️ The VM is still in developement and might be unstable. Be sure to report any problems you encounter in issues, that will be very helpful.
## Examples
Here's an example of a pow method implementation before and after virtualization.
You can find more examples in main.c.
```C
static int pow_normal(int n, int b) {
int r = n;
for (int i = 1; i < b; i++)
r*=n;
return r;
}
static int pow_virt(int n, int b) {
struct vm_context * ctx = vm_makectx();
char code[] = {
// Load params into registers
// mov rax, n
JOINBITS(11, VM_VAL2REG),
VM_MOV,
JOINBITS(0, 0),
ENCODE_QWORD((qword)n),
// mov rbx, b
JOINBITS(11, VM_VAL2REG),
VM_MOV,
JOINBITS(1, 0),
ENCODE_QWORD((qword)b),
// int i = 0;
// mov rdx, 1
JOINBITS(11, VM_VAL2REG),
VM_MOV, JOINBITS(3, 0),
ENCODE_QWORD(1),
// result
// mov rcx, rax
JOINBITS(3, VM_REG2REG),
VM_MOV,
JOINBITS(2, 0),
// loop start
// cmp rdx, rbx
JOINBITS(3, VM_REG2REG),
VM_CMP,
JOINBITS(3, 1),
// jge end_loop if (b >= i) jmp end_loop
// out of scope
JOINBITS(10, VM_REG2REG),
VM_JGE,
ENCODE_QWORD(34), // jump to end_loop
// mul rcx, rax
JOINBITS(3, VM_REG2REG),
VM_MUL,
JOINBITS(2, 0),
// add rdx, 1
JOINBITS(11, VM_VAL2REG),
VM_ADD, JOINBITS(3, 0),
ENCODE_QWORD(1),
// jmp loop_start
JOINBITS(10, VM_VAL2REG),
VM_JMP,
ENCODE_QWORD(-27),
// end_loop
// mov rax, rcx to return in rax
JOINBITS(3, VM_REG2REG),
VM_MOV,
JOINBITS(0, 2)
};
vm_exec(ctx, code, sizeof(code));
qword retval = ctx->rax;
vm_destroyctx(ctx);
return retval;
}
```
Execution flow (The results are the same)
## Usage
To use the VM you will have to write the bytecode manually which can be hard and challenging, but remember it will be double as painful to reverse-engineer. Include the header into your projects by simply including the header.
## TODO
- [ ] Add macros to construct instructions easier (aka JMP(), ADD(), etc)
- [ ] Make a compiler with label support to write the bytecode easier
- [ ] Implement more instructions