cap_reset_ambient - Linux

Overview

cap_reset_ambient is a powerful command in Linux used to change user capabilities in a temporary manner. It allows you to run a program with a specific set of capabilities and reset them back to the original state when the program exits. This command is particularly useful in situations where you need to temporarily grant elevated privileges to a program or script.

Syntax

cap_reset_ambient [--help] [--version] CAPABILITY COMMAND [ARGUMENT [ARGUMENT]...]

Options/Flags

  • --help: Displays the help message and usage instructions.
  • --version: Prints the version information of the cap_reset_ambient command.
  • CAPABILITY: Specifies the capability to be modified. This must be a valid capability name or number.
  • COMMAND: Indicates the program or script to be executed with the modified capability.
  • ARGUMENT [ARGUMENT]…: Additional arguments to be passed to the COMMAND.

Examples

1. Granting elevated privileges to a script:

cap_reset_ambient CAP_SYS_ADMIN ./elevated_script.sh

2. Setting a specific capability value:

cap_reset_ambient 2=ep ./program

3. Resetting capabilities back to the original state:

cap_reset_ambient CAP_SYS_ADMIN

Common Issues

  • Permission denied: Ensure that you have sufficient privileges to modify the capabilities of the process. Running the command as sudo may be necessary.
  • Invalid capability: Check if the specified capability is valid. Use man capabilities to view a list of valid capabilities.

Integration

cap_reset_ambient can be integrated into scripts or command chains to automate privilege management. For example:

#!/bin/bash

# Temporarily grant elevated privileges to a command
cap_reset_ambient CAP_SYS_ADMIN my_command

# Reset the privileges back to the original state
cap_reset_ambient CAP_SYS_ADMIN

Related Commands

  • setcap: Sets the capabilities of a specific binary or script.
  • getcap: Displays the capabilities associated with a file.
  • cap_mkdb: Creates a database of capabilities and their corresponding names.