https://DevOpsCloud.io -- Cloud Monk Losang Jinpa

• Definition: libcap is a library for Linux that provides a POSIX 1003.1e (formerly POSIX.1e) capability interface. It allows applications to perform fine-grained control over the privileges of processes.
• Function: Enables the manipulation of process capabilities, allowing processes to be granted specific privileges without requiring full root permissions.
• Components:

   * '''libcap Library''': The core library that provides functions for managing capabilities.
   * '''capsh Utility''': A command-line tool for setting and querying capabilities.
   * '''Capabilities Header''': Defines the various capabilities that can be assigned to processes.

• Features:

   * '''Fine-Grained Privilege Control''': Allows granting specific capabilities to processes, reducing the need for full root privileges.
   * '''Compatibility''': Provides a standardized way to manage capabilities across different Linux distributions.
   * '''Security Enhancement''': Helps minimize the risk of privilege escalation by limiting the capabilities of processes.

• Usage: Commonly used in applications and scripts that require elevated privileges for specific operations but do not need full root access.

• Setting capabilities on an executable:

   ```bash
   sudo setcap cap_net_bind_service=+ep /usr/bin/example
   ```
   This command grants the `cap_net_bind_service` capability to the `example` executable, allowing it to bind to privileged ports.

• Viewing the capabilities of an executable:

   ```bash
   getcap /usr/bin/example
   ```
   This command displays the capabilities assigned to the `example` executable.

• Using `capsh` to enter a shell with specific capabilities:

   ```bash
   capsh --caps="cap_net_admin,cap_net_raw+ep" -- -c /bin/bash
   ```
   This command opens a new shell with the `cap_net_admin` and `cap_net_raw` capabilities.

• Removing capabilities from an executable:

   ```bash
   sudo setcap -r /usr/bin/example
   ```
   This command removes all capabilities from the `example` executable.

• Example of using `libcap` functions in a C program:

   ```c
   #include 

 int main() {
     cap_t caps;
     caps = cap_get_proc();
     if (caps == NULL) {
         perror("cap_get_proc");
         return 1;
     }
     cap_free(caps);
     return 0;
 }
 ```

• libcap: A Linux library that provides an interface for fine-grained control over process capabilities, allowing specific privileges to be granted to processes without requiring full root access. It enhances security by minimizing the risk of privilege escalation and is commonly used in applications and scripts needing elevated privileges for specific operations.