zig+ollvm跨平台编译的crackme

HOWMP

crackme说明

程序为zig编写，固定注册码。难度主要有

1. 字符串通过comptime(编译时计算)全部加密
2. 通过llvm启动以下功能的pass
   1. ibr:间接分支
   2. icall:间接调用 (call 寄存器)
   3. igv:间接全局变量
   4. junk:花之令
   5. split:基本块分割
   6. sub:指令替换(add/and/sub/or/xor)

跨平台

zig支持交叉编译，大家根据自己电脑自行选择，见附件crackme.zip

windows

crackme-x86_64-windows-gnu.exe
crackme-aarch64-windows-gnu.exe
crackme-x86-windows-gnu.exe

linux

crackme-aarch64-linux-gnu
crackme-x86_64-linux-gnu
crackme-x86-linux-gnu

macos

crackme-aarch64-macos-none
crackme-x86_64-macos-none

源码

见附件src.zip，注册码为解压密码

HOWMP

公布答案

[C] 纯文本查看 复制代码

const std = @import("std");
const os = std.os;
const posix = std.posix;
const key = @import("option").key;
const string = []const u8;

fn encrypt(comptime str: string) [str.len]u8 {
    comptime var enstr: [str.len]u8 = undefined;
    @setEvalBranchQuota(1024 * 1024);
    for (0..str.len) |i| {
        enstr[i] = str[i] ^ key[i % key.len];
    }

    return enstr;
}

inline fn x(comptime str: string) []u8 {
    comptime var e = encrypt(str);
    var buf = (&e).*;
    for (0..buf.len) |i| {
        buf[i] ^= key[i % key.len];
    }
    return buf[0..str.len];
}

inline fn println(str: string) void {
    const writer = std.io.getStdOut().writer();
    _ = writer.write(str) catch unreachable;
    writer.writeByte('\n') catch unreachable;
}

pub fn main() void {
    const reader = std.io.getStdIn().reader();
    println(x("input your flag"));
    var buf: [32]u8 = std.mem.zeroes([32]u8);
    const line = reader.readUntilDelimiter(&buf, '\n') catch {
        println(x("input error 1"));
        return;
    };
    if (line.len != 17) {
        println(x("input error 2"));
        return;
    }

    if (!std.mem.eql(u8, line[0..16], x("d9Be6f0e833709fe"))) {
        println(x("input error 3"));
        return;
    }
    println(x("input ok"));
}