Rev FridaCAUTION

Reverse engineering skills for Claude Code | 逆向工程 Claude Code Skills 插件

The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: rev-frida
description: Generate Frida hook scripts using modern Frida API. Activate when the user wants to write Frida scripts, hook functions at runtime, trace calls or arguments or return values, intercept native or ObjC or Java methods, dump memory or exports, or handle native module load timing for Android and other targets.
---

# rev-frida - Frida Script Generator

Generate Frida instrumentation scripts for dynamic analysis, hooking, and runtime inspection.

## Overview

Use Frida for:
- native export hooks
- Java or ObjC method hooks
- runtime tracing
- argument or return-value capture
- memory dumping
- loader-aware native instrumentation

## Important: Modern Frida CLI

The modern Frida CLI does not use `--no-pause`. A spawned process resumes after the script is loaded.

```bash
# Spawn and hook
frida -U -f com.example.app -l hook.js

# Attach to running process
frida -U com.example.app -l hook.js

# Attach by PID
frida -U -p 1234 -l hook.js
```

## Modern API Reference

### Module & Symbol Lookup

```javascript
const mod = Process.getModuleByName("libssl.so");

mod.name;
mod.base;
mod.size;
mod.path;

const ptr = mod.getExportByName("SSL_read");

Process.enumerateModules();
mod.enumerateExports();
mod.enumerateImports();

const addr = Module.getExportByName(null, "open");
```

### Interceptor

```javascript
Interceptor.attach(ptr, {
    onEnter(args) {
        console.log("arg0:", args[0].toInt32());
        console.log("arg1 str:", args[1].readUtf8String());
    },
    onLeave(retval) {
        console.log("ret:", retval.toInt32());
    }
});

Interceptor.replace(ptr, new NativeCallback(function (a0, a1) {
    console.log("replaced");
    return 0;
}, "int", ["pointer", "int"]));
```

### NativeFunction & NativeCallback

```javascript
const open = new NativeFunction(
    Module.getExportByName(null, "open"),
    "int",
    ["pointer", "int"]
);

const fd = open(Memory.allocUtf8String("/etc/hosts"), 0);

const cb = new NativeCallback(function (arg) {
    console.log("called with:", arg);
    return 0;
}, "int", ["int"]);
```

### Memory Operations

```javascript
ptr(addr).readByteArray(size);
ptr(addr).readUtf8String();
ptr(addr).readU32();
ptr(addr).readPointer();

ptr(addr).writeByteArray(bytes);
ptr(addr).writeUtf8String("hello");
ptr(addr).writeU32(0x41414141);

const buf = Memory.alloc(256);
const str = Memory.allocUtf8String("hello");

Memory.scan(mod.base, mod.size, "48 89 5C 24 ?? 48 89 6C", {
    onMatch(address, size) {
        console.log("found at:", address);
    },
    onComplete() {}
});
```

### ObjC

```javascript
if (ObjC.available) {
    const hook = ObjC.classes.ClassName["- methodName:"];
    Interceptor.attach(hook.implementation, {
        onEnter(args) {
            const selfObj = new ObjC.Object(args[0]);
            const param = new ObjC.Object(args[2]);
            console.log(selfObj.toString());
            console.log(param.toString());
        }
    });
}
```

### Java

```javascript
if (Java.available) {
    Java.perform(function () {
        const Activity = Java.use("android.app.Activity");
        Activity.onCreate.implementation = function (bundle) {
            console.log("onCreate called");
            return this.onCreate(bundle);
        };
    });
}
```

## Script Generation Guidelines

When generating Frida scripts:

1. Always use the modern API such as `Process.getModuleByName()` and `mod.getExportByName()`.
2. Do not use `--no-pause`.
3. Prefer load-event-driven native hooking over polling.
4. Print pointers and buffers in readable form.
5. Wrap risky hooks in `try/catch`.
6. Use `hexdump()` for binary inspection.

### Handle Native Module Load Timing

Do not assume a target `.so` is already loaded.

Preferred order:
1. Hook `android_dlopen_ext` or `dlopen` and install hooks when the target library loads.
2. Use an immediate `Process.findModuleByName()` check for already-loaded modules.
3. Use polling only as a fallback.

Use this helper by default:

```javascript
function hookModuleLoad(moduleName, callback) {
    const dlopen = Module.findGlobalExportByName("android_dlopen_ext")
        || Module.findGlobalExportByName("dlopen");

    if (!dlopen) {
        throw new Error("dlopen/android_dlopen_ext not found");
    }

    const hooked = new Set();

    Interceptor.attach(dlopen, {
        onEnter(args) {
            this.path = args[0].isNull() ? null : args[0].readCString();
            this.shouldHook = this.path && this.path.indexOf(moduleName) !== -1;
        },
        onLeave(retval) {
            if (!this.shouldHook || retval.isNull()) {
                return;
            }

            const mod = Process.findModuleByName(moduleName);
            if (!mod) {
                return;
            }

            const key = mod.base.toString();
            if (hooked.has(key)) {
                return;
            }
            hooked.add(key);

            callback(mod);
        }
    });
}
```

Use it like this:

```javascript
hookModuleLoad("libtarget.so", function (mod) {
    const target = mod.getExportByName("target_export");
    Interceptor.attach(target, {
        onEnter(args) {
            console.log("target_export called");
        }
    });
});
```

If the target may already be loaded, combine an immediate check with the load hook:

```javascript
function hookNowOrOnLoad(moduleName, callback) {
    const mod = Process.findModuleByName(moduleName);
    if (mod) {
        callback(mod);
        return;
    }
    hookModuleLoad(moduleName, callback);
}
```

Use polling only as a fallback:

```javascript
function hookWhenReady(moduleName, exportName, callbacks) {
    const mod = Process.findModuleByName(moduleName);
    if (mod) {
        Interceptor.attach(mod.getExportByName(exportName), callbacks);
        return;
    }

    const timer = setInterval(function () {
        const loaded = Process.findModuleByName(moduleName);
        if (!loaded) {
            return;
        }
        clearInterval(tim

CAUTIONgrade C · trust 79/100 Install with care. The audit found things worth knowing before you trust its output.

What the source does

Filesystem

none-observed

Network

none-observed

Shell

none-observed

Dependencies

pinned

Secrets in source

none-found

Findings (2)

Do not tell the user to hook `.init`, `.init_array`, constructors, or `JNI_OnLoad` blindly.

Gates applied: instruction_override, no_behavioural_pass, no_license.

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