docs: improve secrets documentation

This commit is contained in:
Johannes Kirschbauer
2024-04-26 10:44:14 +02:00
parent 3f8e1c85b6
commit 05f3da28f8
2 changed files with 459 additions and 4 deletions

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## Secrets (CLI Reference)
#### Adding Secrets (set)
```bash
clan secrets set mysecret
> Paste your secret:
```
!!! note
As you type your secret won't be displayed. Press Enter to save the secret.
#### List all Secrets (list)
```bash
clan secrets list
```
#### Assigning Access (set)
By default, secrets are encrypted for your key. To specify which users and machines can access a secret:
```bash
clan secrets set --machine <machine1> --machine <machine2> --user <user1> --user <user2> <secret_name>
```
#### Displaying Secrets (get)
```bash
clan secrets get mysecret
```
#### Rename
TODO
#### Remove
TODO
#### import-sops
TODO
### Users (Reference)
Learn how to manage users and allowing access to existing secrets.
#### list user
Lists all added users
```bash
clan secrets user list
```
``` {.console, title="Example output", .no-copy}
jon
sara
```
!!! Question "Who can execute this command?"
Everyone - completely public.
#### add user
add a user
```bash
clan secrets users add {username} {public-key}
```
!!! Note
Changes can be trusted by maintainer review in version control.
#### get user
get a user public key
```bash
clan secrets users get {username}
```
``` {.console, title="Example output", .no-copy}
age1zk8uzrte55wkg9lkqxu5x6twsj2ja4lehegks0cw4mkg6jv37d9qsjpt44
```
#### remove user
remove a user
```bash
clan secrets users remove {username}
```
!!! Note
Changes can be trusted by maintainer review in version control.
#### add-secret user
Grants the user (`username`) access to the secret (`secret_name`)
```bash
clan secrets users add-secret {username} {secret_name}
```
!!! Note
Requires the executor of the command to have access to the secret (`secret_name`).
#### remove-secret user
remove the user (`username`) from accessing the secret (`secret_name`)
!!! Danger "Make sure at least one person has access."
It might still be possible for the machine to access the secret. (See [machines](#machines))
We highly recommend to use version control such as `git` which allows you to rollback secrets in case anything gets messed up.
```bash
clan secrets users remove-secret {username} {secret_name}
```
!!! Question "Who can execute this command?"
Requires the executor of the command to have access to the secret (`secret_name`).
### Machines (Reference)
- [list](): list machines
- [add](): add a machine
- [get](): get a machine public key
- [remove](): remove a machine
- [add-secret](): allow a machine to access a secret
- [remove-secret](): remove a machine's access to a secret
#### List machine
New machines in Clan come with age keys stored in `./sops/machines/<machine_name>`. To list these machines:
```bash
clan secrets machines list
```
#### Add machine
For clan machines the machine key is generated automatically on demand if none exists.
```bash
clan secrets machines add <machine_name> <age_key>
```
If you already have a device key and want to add it manually, see: [How to obtain a remote key](#obtain-remote-keys-manually)
#### get machine
TODO
#### remove machine
TODO
#### add-secret machine
TODO
#### remove-secret machine
TODO
### Groups (Reference)
The Clan-CLI makes it easy to manage access by allowing you to create groups.
- [list](): list groups
- [add-user](): add a user to group
- [remove-user](): remove a user from group
- [add-machine](): add a machine to group
- [remove-machine](): remove a machine from group
- [add-secret](): allow a user to access a secret
- [remove-secret](): remove a group's access to a secret
#### List Groups
```bash
clan secrets groups list
```
#### add-user
Assign users to a new group, e.g., `admins`:
```bash
clan secrets groups add-user admins <username>
```
!!! info
The group is created if no such group existed before.
The user must exist in beforehand (See: [users](#users-reference))
```{.console, .no-copy}
.
├── flake.nix
. ...
└── sops
├── groups
│ └── admins
│ └── users
│ └── <username> -> ../../../users/<username>
```
#### remove-user
TODO
#### add-machine
TODO
#### remove-machine
TODO
#### add-secret
```bash
clan secrets groups add-secret <group_name> <secret_name>
```
#### remove-secret
TODO
### Key (Reference)
- [generate]() generate age key
- [show]() show age public key
- [update]() re-encrypt all secrets with current keys (useful when changing keys)
#### generate
TODO
#### show
TODO
#### update
TODO
## Further
Secrets in the repository follow this structure:
```{.console, .no-copy}
sops/
├── secrets/
│ └── <secret_name>/
│ ├── secret
│ └── users/
│ └── <your_username>/
```
The content of the secret is stored encrypted inside the `secret` file under `mysecret`.
By default, secrets are encrypted with your key to ensure readability.
### Obtain remote keys manually
To fetch a **SSH host key** from a preinstalled system:
```bash
ssh-keyscan <domain_name> | nix shell nixpkgs#ssh-to-age -c ssh-to-age
```
!!! Success
This command converts the SSH key into an age key on the fly. Since this is the format used by the clan secrets backend.
Once added the **SSH host key** enables seamless integration of existing machines with clan.
Then add the key by executing:
```bash
clan secrets machines add <machine_name> <age_key>
```
See also: [Machine reference](#machines-reference)
### NixOS integration
A NixOS machine will automatically import all secrets that are encrypted for the
current machine. At runtime it will use the host key to decrypt all secrets into
an in-memory, non-persistent filesystem using [sops-nix](https://github.com/Mic92/sops-nix).
In your nixos configuration you can get a path to secrets like this `config.sops.secrets.<name>.path`. For example:
```nix
{ config, ...}: {
sops.secrets.my-password.neededForUsers = true;
users.users.mic92 = {
isNormalUser = true;
passwordFile = config.sops.secrets.my-password.path;
};
}
```
See the [readme](https://github.com/Mic92/sops-nix) of sops-nix for more
examples.
### Migration: Importing existing sops-based keys / sops-nix
`clan secrets` stores each secret in a single file, whereas [sops](https://github.com/Mic92/sops-nix) commonly allows to put all secrets in a yaml or json document.
If you already happened to use sops-nix, you can migrate by using the `clan secrets import-sops` command by importing these files:
```bash
% clan secrets import-sops --prefix matchbox- --group admins --machine matchbox nixos/matchbox/secrets/secrets.yaml
```
This will create secrets for each secret found in `nixos/matchbox/secrets/secrets.yaml` in a `./sops` folder of your repository.
Each member of the group `admins` in this case will be able to decrypt the secrets with their respective key.
Since our clan secret module will auto-import secrets that are encrypted for a particular nixos machine,
you can now remove `sops.secrets.<secrets> = { };` unless you need to specify more options for the secret like owner/group of the secret file.

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@@ -6,7 +6,7 @@ Clan utilizes the [sops](https://github.com/getsops/sops) format and integrates
This documentation will guide you through managing secrets with the Clan CLI
## 1. Initializing Secrets
## Initializing Secrets (Quickstart)
### Create Your Master Keypair
@@ -53,6 +53,137 @@ sops/
└── key.json
```
---
> If you followed the quickstart tutorial all necessary secrets are initialized at this point.
- Continue with [deploying machines](./machines.md)
- Learn about the [basics concept](#concept) of clan secrets
---
## Concept
The secrets system conceptually knows two different entities:
- **Machine**: consumes secrets
- **User**: manages access to secrets
**A Users** Can add or revoke machines' access to secrets.
**A machine** Can decrypt secrets that where encrypted specifically for that machine.
!!! Danger
**Always make sure at least one _User_ has access to a secret**. Otherwise you could lock yourself out from accessing the secret.
### Inherited implications
By default clan uses [sops](https://github.com/getsops/sops) through [sops-nix](https://github.com/Mic92/sops-nix) for managing its secrets which inherits some implications that are important to understand:
- **Public/Private keys**: Entities are identified via their public keys. Each Entity can use their respective private key to decrypt a secret.
- **Public keys are stored**: All Public keys are stored inside the repository
- **Secrets are stored Encrypted**: secrets are stored inside the repository encrypted with the respective public keys
- **Secrets are deployed encrypted**: Fully encrypted secrets are deployed to machines at deployment time.
- **Secrets are decrypted by sops on-demand**: Each machine decrypts its secrets at runtime and stores them at an ephemeral location.
- **Machine key-pairs are auto-generated**: When a machine is created **no user-interaction is required** to setup public/private key-pairs.
- **secrets are re-encrypted**: In case machines, users or groups are modified secrets get re-encrypted on demand.
!!! Important
After revoking access to a secret you should also change the underlying secret. i.e. change the API key, or the password.
---
### Machine and user keys
The following diagrams illustrates how a user can provide a secret (i.e. a Password).
- By using the **Clan CLI** a user encrypts the password with both the **User public-key** and the **machine's public-key**
- The *Machine* can decrypt the password with its private-key on demand.
- The *User* is able to decrypt the password to make changes to it.
```plantuml
@startuml
!include C4_Container.puml
Person(user, "User", "Someone who manages secrets")
ContainerDb(secret, "Secret")
Container(machine, "Machine", "A Machine. i.e. Needs the Secret for a given Service." )
Rel_R(user, secret, "Encrypt", "", "Pubkeys: User, Machine")
Rel_L(secret, user, "Decrypt", "", "user privkey")
Rel_R(secret, machine, "Decrypt", "", "machine privkey" )
@enduml
```
### Groups
It is possible to create semantic groups to make access control more convenient.
#### User groups
Here we illustrate how machine groups work.
Common use cases:
- **Shared Management**: Access among multiple users. I.e. a subset of secrets/machines that have two admins
```plantuml
@startuml
!include C4_Container.puml
System_Boundary(c1, "Group") {
Person(user1, "User A", "has access")
Person(user2, "User B", "has access")
}
ContainerDb(secret, "Secret")
Container(machine, "Machine", "A Machine. i.e. Needs the Secret for a given Service." )
Rel_R(c1, secret, "Encrypt", "", "Pubkeys: User A, User B, Machine")
Rel_R(secret, machine, "Decrypt", "", "machine privkey" )
@enduml
```
<!-- TODO: See also [Groups Reference](#groups-reference) -->
---
#### Machine groups
Here we illustrate how machine groups work.
Common use cases:
- **Shared secrets**: Among multiple machines such as Wifi passwords
```plantuml
@startuml
!include C4_Container.puml
!include C4_Deployment.puml
Person(user, "User", "Someone who manages secrets")
ContainerDb(secret, "Secret")
System_Boundary(c1, "Group") {
Container(machine1, "Machine A", "Both machines need the same secret" )
Container(machine2, "Machine B", "Both machines need the same secret" )
}
Rel_R(user, secret, "Encrypt", "", "Pubkeys: machine A, machine B, User")
Rel(secret, c1, "Decrypt", "", "Both machine A or B can decrypt using their private key" )
@enduml
```
<!-- TODO: See also [Groups Reference](#groups-reference) -->
---
## 2. Adding Machine Keys
New machines in Clan come with age keys stored in `./sops/machines/<machine_name>`. To list these machines: