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diff --git a/doc/ssh/README.md b/doc/ssh/README.md index 5db042326f3..c5b7813b285 100644 --- a/doc/ssh/README.md +++ b/doc/ssh/README.md @@ -8,163 +8,224 @@ you need a secure communication channel for sharing information. The SSH protocol provides this security and allows you to authenticate to the GitLab remote server without supplying your username or password each time. -For a more detailed explanation of how the SSH protocol works, we advise you to -read [this nice tutorial by DigitalOcean](https://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-process). +For a more detailed explanation of how the SSH protocol works, read +[this nice tutorial by DigitalOcean](https://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-process). -## Locating an existing SSH key pair +## Requirements -Before generating a new SSH key pair check if your system already has one -at the default location by opening a shell, or Command Prompt on Windows, -and running the following command: +The only requirement is to have the OpenSSH client installed on your system. This +comes pre-installed on GNU/Linux and macOS, but not on Windows. -**Windows Command Prompt:** +Depending on your Windows version, there are different methods to work with +SSH keys. -```bash -type %userprofile%\.ssh\id_rsa.pub -``` +### Installing the SSH client for Windows 10 -**Git Bash on Windows / GNU/Linux / macOS / PowerShell:** +Starting with Windows 10, you can +[install the Windows Subsystem for Linux (WSL)](https://docs.microsoft.com/en-us/windows/wsl/install-win10) +where you can run Linux distributions directly on Windows, without the overhead +of a virtual machine. Once installed and set up, you'll have the Git and SSH +clients at your disposal. -```bash -cat ~/.ssh/id_rsa.pub -``` +### Installing the SSH client for Windows 8.1 and Windows 7 + +The easiest way to install Git and the SSH client on Windows 8.1 and Windows 7 +is [Git for Windows](https://gitforwindows.com). It provides a BASH +emulation (Git Bash) used for running Git from the command line and the +`ssh-keygen` command that is useful to create SSH keys as you'll learn below. + +NOTE: **Alternative tools:** +Although not explored in this page, you can use some alternative tools. +[Cygwin](https://www.cygwin.com) is a large collection of GNU and open source +tools which provide functionality similar to a Unix distribution. +[PuttyGen](https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html) +provides a graphical user interface to [create SSH keys](https://tartarus.org/~simon/putty-snapshots/htmldoc/Chapter8.html#pubkey-puttygen). + +## Types of SSH keys and which to choose + +GitLab supports RSA, DSA, ECDSA, and ED25519 keys. Their difference lies on +the signing algorithm, and some of them have advantages over the others. For +more information, you can read this +[nice article on ArchWiki](https://wiki.archlinux.org/index.php/SSH_keys#Choosing_the_authentication_key_type). +We'll focus on ED25519 and RSA and here. + +NOTE: **Note:** +As an admin, you can restrict +[which keys should be permitted and their minimum length](../security/ssh_keys_restrictions.md). +By default, all keys are permitted, which is also the case for +[GitLab.com](../user/gitlab_com/index.md#ssh-host-keys-fingerprints). -If you see a string starting with `ssh-rsa` you already have an SSH key pair -and you can skip the generate portion of the next section and skip to the copy -to clipboard step. -If you don't see the string or would like to generate a SSH key pair with a -custom name continue onto the next step. +## ED25519 SSH keys -Note that Public SSH key may also be named as follows: +Following [best practices](https://linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/), +you should always favor [ED25519](https://ed25519.cr.yp.to/) SSH keys, since they +are more secure and have better performance over the other types. -- `id_dsa.pub` -- `id_ecdsa.pub` -- `id_ed25519.pub` +They were introduced in OpenSSH 6.5, so any modern OS should include the +option to create them. If for any reason your OS or the GitLab instance you +interact with doesn't support this, you can fallback to RSA. + +## RSA SSH keys + +RSA keys are the most common ones and therefore the most compatible with +servers that may have an old OpenSSH version. Use them if the GitLab server +doesn't work with ED25519 keys. + +The minimum key size is 1024 bits, defaulting to 2048. If you wish to generate a +stronger RSA key pair, specify the `-b` flag with a higher bit value than the +default. + +The old, default password encoding for SSH private keys keys is +[insecure](https://latacora.singles/2018/08/03/the-default-openssh.html); +it's only a single round of an MD5 hash. Since OpenSSH version 6.5, you should +use the `-o` option to `ssh-keygen` to encode your private key in a new, more +secure format. + +If you already have an RSA SSH key pair to use with GitLab, consider upgrading it +to use the more secure password encryption format by using the following command +on the private key: + +```bash +ssh-keygen -o -f ~/.ssh/id_rsa +``` ## Generating a new SSH key pair -1. To generate a new SSH key pair, use the following command: +Before creating an SSH key pair, make sure to read about the +[different types of keys](#types-of-ssh-keys-and-which-to-choose) to understand +their differences. + +To create a new SSH key pair: - **Git Bash on Windows / GNU/Linux / macOS:** +1. Open a terminal on Linux or macOS, or Git Bash / WSL on Windows. +1. Generate a new ED25519 SSH key pair: ```bash - ssh-keygen -o -t rsa -C "your.email@example.com" -b 4096 + ssh-keygen -t ed25519 -C "email@example.com" ``` - (Note: the `-o` option was introduced in 2014; if this command does not work for you, simply remove the `-o` option and try again) + Or, if you want to use RSA: - **Windows:** + ```bash + ssh-keygen -o -t rsa -b 4096 -C "email@example.com" + ``` - Alternatively on Windows you can download - [PuttyGen](http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html) - and follow [this documentation article][winputty] to generate a SSH key pair. + The `-C` flag adds a comment in the key in case you have multiple of them + and want to tell which is which. It is optional. 1. Next, you will be prompted to input a file path to save your SSH key pair to. + If you don't already have an SSH key pair, use the suggested path by pressing + <kbd>Enter</kbd>. Using the suggested path will normally allow your SSH client + to automatically use the SSH key pair with no additional configuration. - If you don't already have an SSH key pair use the suggested path by pressing - enter. Using the suggested path will normally allow your SSH client - to automatically use the SSH key pair with no additional configuration. + If you already have an SSH key pair with the suggested file path, you will need + to input a new file path and [declare what host](#working-with-non-default-ssh-key-pair-paths) + this SSH key pair will be used for in your `~/.ssh/config` file. - If you already have a SSH key pair with the suggested file path, you will need - to input a new file path and declare what host this SSH key pair will be used - for in your `.ssh/config` file, see [**Working with non-default SSH key pair paths**](#working-with-non-default-ssh-key-pair-paths) - for more information. +1. Once the path is decided, you will be prompted to input a password to + secure your new SSH key pair. It's a best practice to use a password, + but it's not required and you can skip creating it by pressing + <kbd>Enter</kbd> twice. -1. Once you have input a file path you will be prompted to input a password to - secure your SSH key pair. It is a best practice to use a password for an SSH - key pair, but it is not required and you can skip creating a password by - pressing enter. + If, in any case, you want to add or change the password of your SSH key pair, + you can use the `-p`flag: - NOTE: **Note:** - If you want to change the password of your SSH key pair, you can use - `ssh-keygen -p -o -f <keyname>`. - The `-o` option was added in 2014, so if this command does not work for you, - simply remove the `-o` option and try again. + ``` + ssh-keygen -p -o -f <keyname> + ``` -## Adding a SSH key to your GitLab account +Now, it's time to add the newly created public key to your GitLab account. -1. The next step is to copy the public SSH key as we will need it afterwards. +## Adding an SSH key to your GitLab account - To copy your public SSH key to the clipboard, use the appropriate code below: +1. Copy your **public** SSH key to the clipboard by using one of the commands below + depending on your Operating System: **macOS:** ```bash - pbcopy < ~/.ssh/id_rsa.pub + pbcopy < ~/.ssh/id_ed25519.pub ``` - **GNU/Linux (requires the xclip package):** + **WSL / GNU/Linux (requires the xclip package):** ```bash - xclip -sel clip < ~/.ssh/id_rsa.pub + xclip -sel clip < ~/.ssh/id_ed25519.pub ``` - **Windows Command Line:** + **Git Bash on Windows:** ```bash - type %userprofile%\.ssh\id_rsa.pub | clip + cat ~/.ssh/id_ed25519.pub | clip ``` - **Git Bash on Windows / Windows PowerShell:** + You can also open the key in a graphical editor and copy it from there, + but be careful not to accidentally change anything. - ```bash - cat ~/.ssh/id_rsa.pub | clip - ``` - -1. The final step is to add your public SSH key to GitLab. + NOTE: **Note:** + If you opted to create an RSA key, the name might differ. - Navigate to the 'SSH Keys' tab in your 'Profile Settings'. - Paste your key in the 'Key' section and give it a relevant 'Title'. - Use an identifiable title like 'Work Laptop - Windows 7' or - 'Home MacBook Pro 15'. +1. Add your public SSH key to your GitLab account by clicking your avatar + in the upper right corner and selecting **Settings**. From there on, + navigate to **SSH Keys** and paste your public key in the "Key" section. + If you created the key with a comment, this will appear under "Title". + If not, give your key an identifiable title like _Work Laptop_ or + _Home Workstation_, and click **Add key**. + NOTE: **Note:** If you manually copied your public SSH key make sure you copied the entire - key starting with `ssh-rsa` and ending with your email. + key starting with `ssh-ed25519` (or `ssh-rsa`) and ending with your email. + +## Testing that everything is set up correctly + +To test whether your SSH key was added correctly, run the following command in +your terminal (replacing `gitlab.com` with your GitLab's instance domain): -1. Optionally you can test your setup by running `ssh -T git@example.com` - (replacing `example.com` with your GitLab domain) and verifying that you - receive a `Welcome to GitLab` message. +```bash +ssh -T git@gitlab.com +``` + +You should receive a _Welcome to GitLab, `@username`!_ message. + +If the welcome message doesn't appear, run SSH's verbose mode by replacing `-T` +with `-vvvT` to understand where the error is. ## Working with non-default SSH key pair paths If you used a non-default file path for your GitLab SSH key pair, you must configure your SSH client to find your GitLab private SSH key -for connections to your GitLab server (perhaps `gitlab.com`). +for connections to GitLab. -For your current terminal session you can do so using the following commands +Open a terminal and use the following commands (replacing `other_id_rsa` with your private SSH key): -**Git Bash on Windows / GNU/Linux / macOS:** - ```bash eval $(ssh-agent -s) ssh-add ~/.ssh/other_id_rsa ``` -To retain these settings you'll need to save them to a configuration file. -For OpenSSH clients this is configured in the `~/.ssh/config` file for some -operating systems. +To retain these settings, you'll need to save them to a configuration file. +For OpenSSH clients this is configured in the `~/.ssh/config` file. In this +file you can set up configurations for multiple hosts, like GitLab.com, your +own GitLab instance, GitHub, Bitbucket, etc. + Below are two example host configurations using their own SSH key: -``` -# GitLab.com server +```conf +# GitLab.com Host gitlab.com -RSAAuthentication yes -IdentityFile ~/.ssh/config/private-key-filename-01 + Preferredauthentications publickey + IdentityFile ~/.ssh/gitlab_com_rsa -# Private GitLab server +# Private GitLab instance Host gitlab.company.com -RSAAuthentication yes -IdentityFile ~/.ssh/config/private-key-filename + Preferredauthentications publickey + IdentityFile ~/.ssh/example_com_rsa ``` -Due to the wide variety of SSH clients and their very large number of -configuration options, further explanation of these topics is beyond the scope -of this document. - -Public SSH keys need to be unique, as they will bind to your account. -Your SSH key is the only identifier you'll have when pushing code via SSH. -That's why it needs to uniquely map to a single user. +Public SSH keys need to be unique to GitLab, as they will bind to your account. +Your SSH key is the only identifier you'll have when pushing code via SSH, +that's why it needs to uniquely map to a single user. ## Deploy keys @@ -240,8 +301,6 @@ not implicitly give any access just by setting them up. How to add your SSH key to Eclipse: https://wiki.eclipse.org/EGit/User_Guide#Eclipse_SSH_Configuration -[winputty]: https://the.earth.li/~sgtatham/putty/0.67/htmldoc/Chapter8.html#pubkey-puttygen - ## SSH on the GitLab server GitLab integrates with the system-installed SSH daemon, designating a user |