272a8eb36c
- root: reflect razer-bat update - sops: how to list files covered by the sops git attribute - homelab: replace version written when homelab was the root, replace with content map
30 lines
3.8 KiB
Markdown
30 lines
3.8 KiB
Markdown
# sops Encryption/Decryption Workflow in Git
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1. The user creates a file called `secrets.env` anywhere in the repository. This file is [dotenv-formatted](https://stackoverflow.com/questions/68267862/what-is-an-env-or-dotenv-file-exactly) as simple key-value pairs where the value is a secret to be passed into a Stack or container. We want to be able to read the "shape" of the file (the names of the keys), even when the file is encrypted.
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2. The [`.gitattributes`](.gitattributes) file assignes the following properties to files called `secrets.env`:
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1. `filter=sops` which tells the local git instance to run the "sops" filter configured in [`.git/config`](/.git/config).
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2. `diff=sops` which tells the local git instance to run the "sops" diff command instead of the normal `git diff` when diffing `secrets.env` files.
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3. The [`.git/config`](/.git/config) is configured with the "sops" filter and diff blocks referenced above.
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1. `filter.sops.smudge=` will run the thing after the `=` when checking out the repository. This should decrypt our secrets, making them "dirty" again. We call [`decrypt-filter.sh`](/.sops/decrypt-filter.sh) and pass `%f` as a positional argument, which renders to the path of the file being filtered, relative to the repo root (e.g. `homelab/stacks/books/secrets.env`).
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2. `filter.sops.clean=` will run the thing after the `=` when staging changes to commit. This should encrypt our secrets, making them "clean". We call [`encrypt-filter.sh`](/.sops/decrypt-filter.sh) and pass `%f` as a positional argument, which renders to the path of the file being filtered, relative to the repo root (e.g. `homelab/stacks/books/secrets.env`).
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3. `filter.sops.required=true` will ensure that if the scripts fail, the commit will error out.
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4. `diff.sops.textconv=` will use the command after the `=` instead of `git diff` when comparing files. This affects whether files are considered "modified".
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4. When the user stages a new `secrets.env` file at `homelab/stacks/books/secrets.env`, we automatically run `encrypt.sh homelab/stacks/books/secrets.env`. This implictly passes the contents of `secrets.env` to the script at `/dev/stdin`. The script takes the following steps to generate the encrypted content of the file:
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1. Assert privatekey existence at `~/.age/key`.
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2. Determine file extension. For now, we're only working with dotenv-formatted files, but sometimes we also need to support binary files. We use this information to set the `--input-type` parameter.
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3. Encrypt the file contents. This command infers recipients from [`.sops.yaml`](/.sops.yaml). The command uses the privatekey (at `~/.age/key`) of the local user to encrypt the secret. We use [Shamir's secret sharing](https://en.wikipedia.org/wiki/Shamir%27s_secret_sharing) with [sops key groups](https://github.com/getsops/sops?tab=readme-ov-file#215key-groups) to require *at least two of*: author key, CI/CD key, and deploy key. Of course, the original privatekey can always decrypt the secret.
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5. Our new `secrets.env` file is committed to the repository. Encrypted and json-formatted ([why not dotenv-formatted?](https://github.com/getsops/sops/issues/857#issuecomment-2307658865)).
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6. Now we want to deploy our new `homelab/stacks/books` Stack. We'll focus on the sops-related aspects of this process.
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1. Our CI/CD environment is configured with an age keypair. Additional CI/CD environments will each be configured with their own keypairs.
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2. Our deploy environments (hosts) are each configured with an age keypair.
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3. Our [CI/CD script](/.gitea/workflows/homelab_deploy-compose-stack.yml) is configured to decrypt secrets and export the variables before bringing up the Stack.
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### List Files Managed by sops
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```sh
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git ls-files |\
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git check-attr -a --stdin |\
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grep 'filter: sops' |\
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cut -d':' -f1
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``` |