> For the complete documentation index, see [llms.txt](https://playbook.sidthoviti.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://playbook.sidthoviti.com/devsecops/secure-coding/code-review-examples/lfi.md).

# LFI

**Example 1: PHP**

**Vulnerable Code:**

```php
phpCopy code<?php
include($_GET['file']);
?>
```

**Reason for vulnerability:** User input is directly included, allowing LFI.

**Fixed Code:**

```php
phpCopy code<?php
$file = basename($_GET['file']);
include("/var/www/html/" . $file);
?>
```

**Reason for fix:** Sanitize user input and restrict to allowed directories.

**Example 2: Python**

**Vulnerable Code:**

```python
pythonCopy code@app.route('/view')
def view():
    file = request.args.get('file')
    with open(file, 'r') as f:
        return f.read()
```

**Reason for vulnerability:** User input is directly used in the file path, allowing LFI.

**Fixed Code:**

```python
pythonCopy code@app.route('/view')
def view():
    file = os.path.basename(request.args.get('file'))
    with open(os.path.join('/var/www/html', file), 'r') as f:
        return f.read()
```

**Reason for fix:** Sanitize user input and restrict to allowed directories.

***

### PHP Example

#### Vulnerable Code:

```php
phpCopy<?php
$page = $_GET['page'];
include($page . '.php');
?>
```

#### Reason for Vulnerability:

This code allows an attacker to include arbitrary files from the local filesystem.

#### Fixed Code:

```php
phpCopy<?php
$allowed_pages = ['home', 'about', 'contact'];
$page = $_GET['page'];

if (!in_array($page, $allowed_pages)) {
    die('Invalid page');
}

include $page . '.php';
?>
```

#### Reason for Fix:

The fixed code uses a whitelist of allowed pages to prevent inclusion of arbitrary files.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://playbook.sidthoviti.com/devsecops/secure-coding/code-review-examples/lfi.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.