# sharesec

In Samba, **sharesec** refers to the mechanism (typically implemented as a TDB file, often named `sharesec.tdb`) that stores share-level security information. This data defines the access control lists (ACLs) for Samba shares—separate from the underlying filesystem permissions—mimicking the behavior of Windows share permissions.

## Overview

* **Purpose**:\
  `sharesec` holds the security descriptors for Samba shares. It determines which users or groups have access to a particular share and what level of access (read, write, full control) they have.
* **Storage Mechanism**:\
  The share security information is stored in a Trivial Database (TDB) file, typically named `sharesec.tdb`, which is maintained by Samba. This file is automatically managed by Samba and is used to enforce share-level permissions when clients connect.
* **Integration with Windows**:\
  By implementing share-level ACLs similar to Windows, Samba can provide a more familiar security model for Windows clients, ensuring consistent behavior across a mixed-OS environment.

## Key Functions

* **Access Control**:\
  Controls which users and groups can access a share and with what permissions. These settings complement filesystem-level permissions.
* **Windows-Like Security Model**:\
  Allows Samba to emulate Windows share permissions, facilitating integration in networks where Windows and Unix systems coexist.
* **Administrative Management**:\
  Administrators can indirectly manage share security through Samba configuration (using tools like `smb.conf` and various Samba utilities) rather than editing the `sharesec.tdb` file directly.

## Usage and Management

* **Automatic Handling**:\
  Samba automatically updates `sharesec.tdb` when changes are made to share permissions via configuration or administrative tools (e.g., using `net rpc share` commands).
*   **Administrative Tools**:\
    While direct editing of `sharesec.tdb` is uncommon, you can query or modify share security settings using Samba commands. For example:

    ```bash
    net rpc share info <sharename> -U <admin_user>
    ```

    This command displays detailed share information, including security settings stored in `sharesec.tdb`.

## Best Practices

* **Backup**:\
  Regularly include `sharesec.tdb` in your Samba backups to ensure that share security settings can be restored in case of corruption or accidental loss.
* **Security**:\
  Set strict file permissions on `sharesec.tdb` so that only the Samba process and trusted administrators can access it.
* **Monitoring**:\
  Keep an eye on changes to share permissions and audit logs to detect unauthorized modifications.

## Conclusion

The **sharesec** mechanism, typically implemented as `sharesec.tdb` in Samba, is crucial for managing share-level ACLs. By emulating Windows share permissions, it enables consistent and secure access control across mixed operating system environments. Proper backup, security, and monitoring of `sharesec.tdb` are essential to maintain the integrity of your Samba share security settings.
