Git Credential Store

The git-credential-store helper in Git is a credential management feature that allows you to save Git credentials (such as usernames and personal access tokens) in a plain-text file. This file is often located in the home directory as ~/.git-credentials. The credential-store helper is useful when you want to avoid being prompted for credentials each time you access a Git repository. However, this method is less secure than using a credential manager like Git Credential Manager (GCM), as it stores credentials in plain text.

1. How the git-credential-store Helper Works

• When configured, the git-credential-store helper saves credentials in a plain text file, so Git can retrieve them automatically when required for authentication.

• This setup is straightforward for single-user environments or systems where security restrictions are less stringent.

2. Configuring the git-credential-store Helper

• Step 1: Set up Git to use the credential-store helper.

  git config --global credential.helper store

• This command sets up Git to save credentials globally (for all repositories of the current user).

• Step 2: After configuring, run any Git command that requires authentication, such as cloning a private repository:

  git clone https://github.com/your-username/your-repository.git

• Git will prompt you for your username and password (or personal access token). After entering your credentials, they will be stored in the ~/.git-credentials file, formatted as follows:

  https://username:[email protected]

• Example of ~/.git-credentials:

  https://user1:[email protected]
  https://user2:[email protected]

• Each line in this file represents a different set of credentials for a unique URL or repository host.

3. Configuring Multiple Credentials for Different Repositories

By default, the credential-store helper applies credentials globally, meaning it will try to use the same credentials for all repositories. To use different credentials for different repositories, you can specify credentials based on the repository’s URL in the ~/.git-credentials file.

Example Scenario

Let’s say you have two Git repositories:

• Repository on GitHub: https://github.com/user1/repo1

• Repository on GitLab: https://gitlab.com/user2/repo2

To use different credentials for each repository, add both sets of credentials to ~/.git-credentials:

https://user1:[email protected]
https://user2:[email protected]

With this setup:

• When you access github.com repositories, Git uses user1's credentials.

• When you access gitlab.com repositories, Git uses user2's credentials.

Configuration Steps

1. Manually Edit ~/.git-credentials:

   • Open the ~/.git-credentials file in a text editor:

     nano ~/.git-credentials

   • Add entries for each set of credentials in the following format:

     https://username:personal_access_token@repository_host

   • Example:

     https://user1:[email protected]
     https://user2:[email protected]

2. Ensure URL Specificity:

   • Git matches the URL specified in the ~/.git-credentials file with the repository URL you’re accessing.

   • If you want more specific control, use the full URL for each repository:

     https://user1:[email protected]/user1/repo1
     https://user2:[email protected]/user2/repo2

4. Using Different Credentials for the Same Git Host

If you need to use different credentials for different repositories on the same host (e.g., multiple GitHub accounts), then specify the full URL path for each repository in ~/.git-credentials.

Example:

https://user1:[email protected]/user1/repo1
https://user2:[email protected]/user2/repo2

This way, Git can differentiate based on the repository URL, even if both repositories are hosted on the same domain.

5. Alternative: Configuring Credentials Per Repository Using Local Configuration

If you want to avoid adding credentials globally, you can configure credentials per repository using local Git configuration.

1. Set Up credential.helper store Locally:

   • Navigate to the repository’s directory:

     cd /path/to/repository

   • Set up the credential-store helper for this repository only:

     git config credential.helper store

   • After running this command, the credentials you enter for this repository will be saved specifically for it, without affecting other repositories.

2. Test with Git Command:

   • Run any Git command that requires authentication (like git push or git pull). Git will prompt for your credentials, which will be saved in the repository-specific configuration.

6. Security Considerations

• Plain Text Storage: Since ~/.git-credentials is stored in plain text, restrict permissions to secure the file:

  chmod 600 ~/.git-credentials

• Using Alternative Credential Managers: For improved security, consider using Git Credential Manager (GCM) or SSH keys, as they offer encrypted credential storage.

Summary of Commands and File Setup

Command or File	Purpose
git config --global credential.helper store	Enables global credential storage in ~/.git-credentials.
~/.git-credentials	Stores credentials for specific hosts and repositories.
chmod 600 ~/.git-credentials	Restricts access to the credentials file for security.
git config credential.helper store	Sets credential storage for a specific repository (in local repo config).

This approach to managing Git credentials in ~/.git-credentials helps avoid repeated prompts while ensuring different credentials are used for different repositories.

Your example in ~/.git-credentials file is formatted correctly to store credentials for different Git hosts:

https://user1:[email protected]
https://user2:[email protected]

Explanation of the Format

Each line specifies a set of credentials for a specific host or repository. Here’s how it works:

• Format: https://username:token@host

  • https://: The protocol for Git operations over HTTPS.

  • username: The Git username for the host (in this case, user1 for GitHub and user2 for GitLab).

  • token: The personal access token (PAT) for each user on their respective hosts (ghp_githubAccessToken for GitHub and glp_gitlabAccessToken for GitLab).

  • host: The Git host URL (github.com for GitHub and gitlab.com for GitLab).

How Git Uses This File

When you perform a Git operation that requires authentication, Git will:

1. Check the ~/.git-credentials file for an entry that matches the URL you’re accessing.

2. Use the matching username and token to authenticate without prompting for a password.

For example:

• When you run a command like git clone https://github.com/user1/repo1, Git will find https://user1:[email protected] in ~/.git-credentials and use user1's credentials.

• When you run a command for GitLab, like git clone https://gitlab.com/user2/repo2, it will use https://user2:[email protected].

Security Consideration

Since ~/.git-credentials stores credentials in plain text, limit its permissions for security:

chmod 600 ~/.git-credentials

This ensures that only your user can read or write to the file, keeping the credentials secure from other users on the system.