go.mozilla.org/sops
sops is an editor of encrypted files that supports YAML, JSON, ENV, INI and BINARY
formats and encrypts with AWS KMS, GCP KMS, Azure Key Vault and PGP.
(demo <https://www.youtube.com/watch?v=YTEVyLXFiq0>_)
.. image:: https://i.imgur.com/X0TM5NI.gif
.. image:: https://godoc.org/go.mozilla.org/sops?status.svg :target: https://godoc.org/go.mozilla.org/sops
.. image:: https://travis-ci.org/mozilla/sops.svg?branch=master :target: https://travis-ci.org/mozilla/sops
Stable release
Binaries and packages of the latest stable release are available at `https://github.com/mozilla/sops/releases <https://github.com/mozilla/sops/releases>`_.
Development branch
For the adventurous, unstable features are available in the develop branch, which you can install from source:
.. code:: bash
$ go get -u go.mozilla.org/sops/cmd/sops
$ cd $GOPATH/src/go.mozilla.org/sops/
$ git checkout develop
$ make install
(requires Go >= 1.12)
If you don't have Go installed, set it up with:
.. code:: bash
$ {apt,yum,brew} install golang
$ echo 'export GOPATH=~/go' >> ~/.bashrc
$ source ~/.bashrc
$ mkdir $GOPATH
Or whatever variation of the above fits your system and shell.
To use sops as a library, take a look at the decrypt package <https://godoc.org/go.mozilla.org/sops/decrypt>_.
Questions? ping "ulfr" and "autrilla" in #security on irc.mozilla.org <https://wiki.mozilla.org/IRC>_
(use a web client like mibbit <https://chat.mibbit.com>_ ).
What happened to Python Sops? We rewrote Sops in Go to solve a number of
deployment issues, but the Python branch still exists under python-sops. We
will keep maintaining it for a while, and you can still pip install sops,
but we strongly recommend you use the Go version instead.
.. sectnum:: .. contents:: Table of Contents
For a quick presentation of Sops, check out this Youtube tutorial:
.. image:: https://img.youtube.com/vi/V2PRhxphH2w/0.jpg :target: https://www.youtube.com/watch?v=V2PRhxphH2w
If you're using AWS KMS, create one or multiple master keys in the IAM console and export them, comma separated, in the SOPS_KMS_ARN env variable. It is recommended to use at least two master keys in different regions.
.. code:: bash
export SOPS_KMS_ARN="arn:aws:kms:us-east-1:656532927350:key/920aff2e-c5f1-4040-943a-047fa387b27e,arn:aws:kms:ap-southeast-1:656532927350:key/9006a8aa-0fa6-4c14-930e-a2dfb916de1d"
Your AWS credentials must be present in ~/.aws/credentials. sops uses aws-sdk-go.
.. code::
$ cat ~/.aws/credentials
[default]
aws_access_key_id = AKI.....
aws_secret_access_key = mw......
If you want to use PGP, export the fingerprints of the public keys, comma separated, in the SOPS_PGP_FP env variable.
.. code:: bash
export SOPS_PGP_FP="85D77543B3D624B63CEA9E6DBC17301B491B3F21,E60892BB9BD89A69F759A1A0A3D652173B763E8F"
Note: you can use both PGP and KMS simultaneously.
Then simply call sops with a file path as argument. It will handle the
encryption/decryption transparently and open the cleartext file in an editor
.. code:: shell
$ sops mynewtestfile.yaml
mynewtestfile.yaml doesn't exist, creating it.
please wait while an encryption key is being generated and stored in a secure fashion
file written to mynewtestfile.yaml
Editing will happen in whatever $EDITOR is set to, or, if it's not set, in vim.
Keep in mind that sops will wait for the editor to exit, and then try to reencrypt
the file. Some GUI editors (atom, sublime) spawn a child process and then exit
immediately. They usually have an option to wait for the main editor window to be
closed before exiting. See #127 <https://github.com/mozilla/sops/issues/127>_ for
more information.
The resulting encrypted file looks like this:
.. code:: yaml
myapp1: ENC[AES256_GCM,data:Tr7o=,iv:1=,aad:No=,tag:k=]
app2:
db:
user: ENC[AES256_GCM,data:CwE4O1s=,iv:2k=,aad:o=,tag:w==]
password: ENC[AES256_GCM,data:p673w==,iv:YY=,aad:UQ=,tag:A=]
# private key for secret operations in app2
key: |-
ENC[AES256_GCM,data:Ea3kL5O5U8=,iv:DM=,aad:FKA=,tag:EA==]
an_array:
- ENC[AES256_GCM,data:v8jQ=,iv:HBE=,aad:21c=,tag:gA==]
- ENC[AES256_GCM,data:X10=,iv:o8=,aad:CQ=,tag:Hw==]
- ENC[AES256_GCM,data:KN=,iv:160=,aad:fI4=,tag:tNw==]
sops:
kms:
- created_at: 1441570389.775376
enc: CiC....Pm1Hm
arn: arn:aws:kms:us-east-1:656532927350:key/920aff2e-c5f1-4040-943a-047fa387b27e
- created_at: 1441570391.925734
enc: Ci...awNx
arn: arn:aws:kms:ap-southeast-1:656532927350:key/9006a8aa-0fa6-4c14-930e-a2dfb916de1d
pgp:
- fp: 85D77543B3D624B63CEA9E6DBC17301B491B3F21
created_at: 1441570391.930042
enc: |
-----BEGIN PGP MESSAGE-----
hQIMA0t4uZHfl9qgAQ//UvGAwGePyHuf2/zayWcloGaDs0MzI+zw6CmXvMRNPUsA
...=oJgS
-----END PGP MESSAGE-----
A copy of the encryption/decryption key is stored securely in each KMS and PGP block. As long as one of the KMS or PGP method is still usable, you will be able to access your data.
To decrypt a file in a cat fashion, use the -d flag:
.. code:: bash
$ sops -d mynewtestfile.yaml
sops encrypted files contain the necessary information to decrypt their content.
All a user of sops needs is valid AWS credentials and the necessary
permissions on KMS keys.
Given that, the only command a sops user needs is:
.. code:: bash
$ sops <file>
<file> will be opened, decrypted, passed to a text editor (vim by default),
encrypted if modified, and saved back to its original location. All of these
steps, apart from the actual editing, are transparent to the user.
Test with the dev PGP key
If you want to test **sops** without having to do a bunch of setup, you can use
the example files and pgp key provided with the repository::
$ git clone https://github.com/mozilla/sops.git
$ cd sops
$ gpg --import pgp/sops_functional_tests_key.asc
$ sops example.yaml
This last step will decrypt ``example.yaml`` using the test private key.
Encrypting using GCP KMS
~~~~~~~~~~~~~~~~~~~~~~~~
GCP KMS uses `Application Default Credentials
<https://developers.google.com/identity/protocols/application-default-credentials>`_.
If you already logged in using
.. code:: bash
$ gcloud auth login
you can enable application default credentials using the sdk::
$ gcloud auth application-default login
Encrypting/decrypting with GCP KMS requires a KMS ResourceID. You can use the
cloud console the get the ResourceID or you can create one using the gcloud
sdk:
.. code:: bash
$ gcloud kms keyrings create sops --location global
$ gcloud kms keys create sops-key --location global --keyring sops --purpose encryption
$ gcloud kms keys list --location global --keyring sops
# you should see
NAME PURPOSE PRIMARY_STATE
projects/my-project/locations/global/keyRings/sops/cryptoKeys/sops-key ENCRYPT_DECRYPT ENABLED
Now you can encrypt a file using::
$ sops --encrypt --gcp-kms projects/my-project/locations/global/keyRings/sops/cryptoKeys/sops-key test.yaml > test.enc.yaml
And decrypt it using::
$ sops --decrypt test.enc.yaml
Encrypting using Azure Key Vault
The Azure Key Vault integration uses service principals to access secrets in the vault. The following environment variables are used to authenticate:
.. code:: bash
AZURE_TENANT_ID
AZURE_CLIENT_ID
AZURE_CLIENT_SECRET
You can create a service principal using the cli like this:
.. code:: bash
$ az ad sp create-for-rbac -n my-keyvault-sp
{
"appId": "<some-uuid>",
"displayName": "my-keyvault-sp",
"name": "http://my-keyvault-sp",
"password": "<some-uuid>",
"tenant": "<tenant-id>"
}
The appId is the client id, and the password is the client secret.
Encrypting/decrypting with Azure Key Vault requires the resource identifier for a key. This has the following form::
https://${VAULT_URL}/keys/${KEY_NAME}/${KEY_VERSION}
To create a Key Vault and assign your service principal permissions on it from the commandline:
.. code:: bash
# Create a resource group if you do not have one:
$ az group create --name sops-rg --location westeurope
# Key Vault names are globally unique, so generate one:
$ keyvault_name=sops-$(uuidgen | tr -d - | head -c 16)
# Create a Vault, a key, and give the service principal access:
$ az keyvault create --name $keyvault_name --resource-group sops-rg --location westeurope
$ az keyvault key create --name sops-key --vault-name $keyvault_name --protection software --ops encrypt decrypt
$ az keyvault set-policy --name $keyvault_name --resource-group sops-rg --spn $AZURE_CLIENT_ID \
--key-permissions encrypt decrypt
# Read the key id:
$ az keyvault key show --name sops-key --vault-name $keyvault_name --query key.kid
https://sops.vault.azure.net/keys/sops-key/some-string
Now you can encrypt a file using::
$ sops --encrypt --azure-kv https://sops.vault.azure.net/keys/sops-key/some-string test.yaml > test.enc.yaml
And decrypt it using::
$ sops --decrypt test.enc.yaml
Adding and removing keys
When creating new files, ``sops`` uses the PGP, KMS and GCP KMS defined in the
command line arguments ``--kms``, ``--pgp``, ``--gcp-kms`` or ``--azure-kv``, or from
the environment variables ``SOPS_KMS_ARN``, ``SOPS_PGP_FP``, ``SOPS_GCP_KMS_IDS``,
``SOPS_AZURE_KEYVAULT_URL``. That information is stored in the file under the
``sops`` section, such that decrypting files does not require providing those
parameters again.
Master PGP and KMS keys can be added and removed from a ``sops`` file in one of
two ways: by using command line flag, or by editing the file directly.
Command line flag ``--add-kms``, ``--add-pgp``, ``--add-gcp-kms``, ``--add-azure-kv``,
``--rm-kms``, ``--rm-pgp``, ``--rm-gcp-kms`` and ``--rm-azure-kv`` can be used to add
and remove keys from a file.
These flags use the comma separated syntax as the ``--kms``, ``--pgp``, ``--gcp-kms``
and ``--azure-kv`` arguments when creating new files.
.. code:: bash
# add a new pgp key to the file and rotate the data key
$ sops -r -i --add-pgp 85D77543B3D624B63CEA9E6DBC17301B491B3F21 example.yaml
# remove a pgp key from the file and rotate the data key
$ sops -r -i --rm-pgp 85D77543B3D624B63CEA9E6DBC17301B491B3F21 example.yaml
Alternatively, invoking ``sops`` with the flag **-s** will display the master keys
while editing. This method can be used to add or remove kms or pgp keys under the
sops section. Invoking ``sops`` with the **-i** flag will perform an in-place edit
instead of redirecting output to ``stdout``.
For example, to add a KMS master key to a file, add the following entry while
editing:
.. code:: yaml
sops:
kms:
- arn: arn:aws:kms:us-east-1:656532927350:key/920aff2e-c5f1-4040-943a-047fa387b27e
And, similarly, to add a PGP master key, we add its fingerprint:
.. code:: yaml
sops:
pgp:
- fp: 85D77543B3D624B63CEA9E6DBC17301B491B3F21
When the file is saved, ``sops`` will update its metadata and encrypt the data key
with the freshly added master keys. The removed entries are simply deleted from
the file.
When removing keys, it is recommended to rotate the data key using ``-r``,
otherwise owners of the removed key may have add access to the data key in the
past.
KMS AWS Profiles
~~~~~~~~~~~~~~~~
If you want to use a specific profile, you can do so with `aws_profile`:
.. code:: yaml
sops:
kms:
- arn: arn:aws:kms:us-east-1:656532927350:key/920aff2e-c5f1-4040-943a-047fa387b27e
aws_profile: foo
If no AWS profile is set, default credentials will be used.
Similarly the `--aws-profile` flag can be set with the command line with any of the KMS commands.
Assuming roles and using KMS in various AWS accounts
SOPS has the ability to use KMS in multiple AWS accounts by assuming roles in each account. Being able to assume roles is a nice feature of AWS that allows administrators to establish trust relationships between accounts, typically from the most secure account to the least secure one. In our use-case, we use roles to indicate that a user of the Master AWS account is allowed to make use of KMS master keys in development and staging AWS accounts. Using roles, a single file can be encrypted with KMS keys in multiple accounts, thus increasing reliability and ease of use.
You can use keys in various accounts by tying each KMS master key to a role that
the user is allowed to assume in each account. The IAM roles <http://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_use.html>_
documentation has full details on how this needs to be configured on AWS's side.
From the point of view of sops, you only need to specify the role a KMS key
must assume alongside its ARN, as follows:
.. code:: yaml
sops:
kms:
- arn: arn:aws:kms:us-east-1:656532927350:key/920aff2e-c5f1-4040-943a-047fa387b27e
role: arn:aws:iam::927034868273:role/sops-dev-xyz
The role must have permission to call Encrypt and Decrypt using KMS. An example policy is shown below.
.. code:: json
{
"Sid": "Allow use of the key",
"Effect": "Allow",
"Action": [
"kms:Encrypt",
"kms:Decrypt",
"kms:ReEncrypt*",
"kms:GenerateDataKey*",
"kms:DescribeKey"
],
"Resource": "*",
"Principal": {
"AWS": [
"arn:aws:iam::927034868273:role/sops-dev-xyz"
]
}
}
You can specify a role in the --kms flag and SOPS_KMS_ARN variable by
appending it to the ARN of the master key, separated by a + sign::
<KMS ARN>+<ROLE ARN>
arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500+arn:aws:iam::927034868273:role/sops-dev-xyz
AWS KMS Encryption Context
SOPS has the ability to use `AWS KMS key policy and encryption context
<http://docs.aws.amazon.com/kms/latest/developerguide/encryption-context.html>`_
to refine the access control of a given KMS master key.
When creating a new file, you can specify encryption context in the
``--encryption-context`` flag by comma separated list of key-value pairs:
.. code:: bash
$ sops --encryption-context Environment:production,Role:web-server test.dev.yaml
The format of the Encrypt Context string is ``<EncryptionContext Key>:<EncryptionContext Value>,<EncryptionContext Key>:<EncryptionContext Value>,...``
The encryption context will be stored in the file metadata and does
not need to be provided at decryption.
Encryption contexts can be used in conjunction with KMS Key Policies to define
roles that can only access a given context. An example policy is shown below:
.. code:: json
{
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::111122223333:role/RoleForExampleApp"
},
"Action": "kms:Decrypt",
"Resource": "*",
"Condition": {
"StringEquals": {
"kms:EncryptionContext:AppName": "ExampleApp",
"kms:EncryptionContext:FilePath": "/var/opt/secrets/"
}
}
}
Key Rotation
~~~~~~~~~~~~
It is recommended to renew the data key on a regular basis. ``sops`` supports key
rotation via the ``-r`` flag. Invoking it on an existing file causes sops to
reencrypt the file with a new data key, which is then encrypted with the various
KMS and PGP master keys defined in the file.
.. code:: bash
sops -r example.yaml
Using .sops.yaml conf to select KMS/PGP for new files
It is often tedious to specify the --kms --gcp-kms and --pgp parameters for creation
of all new files. If your secrets are stored under a specific directory, like a
git repository, you can create a .sops.yaml configuration file at the root
directory to define which keys are used for which filename.
Let's take an example:
Under those circumstances, a file placed at mysecretrepo/.sops.yaml can manage the three sets of configurations for the three types of files:
.. code:: yaml
# creation rules are evaluated sequentially, the first match wins
creation_rules:
# upon creation of a file that matches the pattern *.dev.yaml,
# KMS set A is used
- path_regex: \.dev\.yaml$
kms: 'arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500,arn:aws:kms:us-west-2:361527076523:key/5052f06a-5d3f-489e-b86c-57201e06f31e+arn:aws:iam::361527076523:role/hiera-sops-prod'
pgp: '1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A'
# prod files use KMS set B in the PROD IAM
- path_regex: \.prod\.yaml$
kms: 'arn:aws:kms:us-west-2:361527076523:key/5052f06a-5d3f-489e-b86c-57201e06f31e+arn:aws:iam::361527076523:role/hiera-sops-prod,arn:aws:kms:eu-central-1:361527076523:key/cb1fab90-8d17-42a1-a9d8-334968904f94+arn:aws:iam::361527076523:role/hiera-sops-prod'
pgp: '1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A'
# gcp files using GCP KMS
- path_regex: \.gcp\.yaml$
gcp_kms: projects/mygcproject/locations/global/keyRings/mykeyring/cryptoKeys/thekey
# Finally, if the rules above have not matched, this one is a
# catchall that will encrypt the file using KMS set C
# The absence of a path_regex means it will match everything
- kms: 'arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500,arn:aws:kms:us-west-2:142069644989:key/846cfb17-373d-49b9-8baf-f36b04512e47,arn:aws:kms:us-west-2:361527076523:key/5052f06a-5d3f-489e-b86c-57201e06f31e'
pgp: '1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A'
When creating any file under mysecretrepo, whether at the root or under
a subdirectory, sops will recursively look for a .sops.yaml file. If one is
found, the filename of the file being created is compared with the filename
regexes of the configuration file. The first regex that matches is selected,
and its KMS and PGP keys are used to encrypt the file. It should be noted that
the looking up of .sops.yaml is from the working directory (CWD) instead of
the directory of the encrypting file (see Issue 242 <https://github.com/mozilla/sops/issues/242>_).
The path_regex checks the full path of the encrypting file. Here is another example:
.. code:: yaml
creation_rules:
# upon creation of a file under development,
# KMS set A is used
- path_regex: .*/development/.*
kms: 'arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500,arn:aws:kms:us-west-2:361527076523:key/5052f06a-5d3f-489e-b86c-57201e06f31e+arn:aws:iam::361527076523:role/hiera-sops-prod'
pgp: '1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A'
# prod files use KMS set B in the PROD IAM
- path_regex: .*/production/.*
kms: 'arn:aws:kms:us-west-2:361527076523:key/5052f06a-5d3f-489e-b86c-57201e06f31e+arn:aws:iam::361527076523:role/hiera-sops-prod,arn:aws:kms:eu-central-1:361527076523:key/cb1fab90-8d17-42a1-a9d8-334968904f94+arn:aws:iam::361527076523:role/hiera-sops-prod'
pgp: '1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A'
# other files use KMS set C
- kms: 'arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500,arn:aws:kms:us-west-2:142069644989:key/846cfb17-373d-49b9-8baf-f36b04512e47,arn:aws:kms:us-west-2:361527076523:key/5052f06a-5d3f-489e-b86c-57201e06f31e'
pgp: '1022470DE3F0BC54BC6AB62DE05550BC07FB1A0A'
Creating a new file with the right keys is now as simple as
.. code:: bash
$ sops <newfile>.prod.yaml
Note that the configuration file is ignored when KMS or PGP parameters are passed on the sops command line or in environment variables.
Specify a different GPG executable
``sops`` checks for the ``SOPS_GPG_EXEC`` environment variable. If specified,
it will attempt to use the executable set there instead of the default
of ``gpg``.
Example: place the following in your ``~/.bashrc``
.. code:: bash
SOPS_GPG_EXEC = 'your_gpg_client_wrapper'
Specify a different GPG key server
By default, sops uses the key server gpg.mozilla.org to retrieve the GPG
keys that are not present in the local keyring.
To use a different GPG key server, set the SOPS_GPG_KEYSERVER environment
variable.
Example: place the following in your ~/.bashrc
.. code:: bash
SOPS_GPG_KEYSERVER = 'gpg.example.com'
Key groups
By default, ``sops`` encrypts the data key for a file with each of the master keys,
such that if any of the master keys is available, the file can be decrypted.
However, it is sometimes desirable to require access to multiple master keys
in order to decrypt files. This can be achieved with key groups.
When using key groups in sops, data keys are split into parts such that keys from
multiple groups are required to decrypt a file. ``sops`` uses Shamir's Secret Sharing
to split the data key such that each key group has a fragment, each key in the
key group can decrypt that fragment, and a configurable number of fragments (threshold)
are needed to decrypt and piece together the complete data key. When decrypting a
file using multiple key groups, ``sops`` goes through key groups in order, and in
each group, tries to recover the fragment of the data key using a master key from
that group. Once the fragment is recovered, ``sops`` moves on to the next group,
until enough fragments have been recovered to obtain the complete data key.
By default, the threshold is set to the number of key groups. For example, if
you have three key groups configured in your SOPS file and you don't override
the default threshold, then one master key from each of the three groups will
be required to decrypt the file.
Management of key groups is done with the ``sops groups`` command.
For example, you can add a new key group with 3 PGP keys and 3 KMS keys to the
file ``my_file.yaml``:
.. code:: bash
$ sops groups add --file my_file.yaml --pgp fingerprint1 --pgp fingerprint2 --pgp fingerprint3 --kms arn1 --kms arn2 --kms arn3
Or you can delete the 1st group (group number 0, as groups are zero-indexed)
from ``my_file.yaml``:
.. code:: bash
$ sops groups delete --file my_file.yaml 0
Key groups can also be specified in the ``.sops.yaml`` config file,
like so:
.. code:: yaml
creation_rules:
- path_regex: .*keygroups.*
key_groups:
# First key group
- pgp:
- fingerprint1
- fingerprint2
kms:
- arn: arn1
role: role1
context:
foo: bar
- arn: arn2
# Second key group
- pgp:
- fingerprint3
- fingerprint4
kms:
- arn: arn3
- arn: arn4
# Third key group
- pgp:
- fingerprint5
Given this configuration, we can create a new encrypted file like we normally
would, and optionally provide the ``--shamir-secret-sharing-threshold`` command line
flag if we want to override the default threshold. ``sops`` will then split the data
key into three parts (from the number of key groups) and encrypt each fragment with
the master keys found in each group.
For example:
.. code:: bash
$ sops --shamir-secret-sharing-threshold 2 example.json
Alternatively, you can configure the Shamir threshold for each creation rule in the ``.sops.yaml`` config
with ``shamir_threshold``:
.. code:: yaml
creation_rules:
- path_regex: .*keygroups.*
shamir_threshold: 2
key_groups:
# First key group
- pgp:
- fingerprint1
- fingerprint2
kms:
- arn: arn1
role: role1
context:
foo: bar
- arn: arn2
# Second key group
- pgp:
- fingerprint3
- fingerprint4
kms:
- arn: arn3
- arn: arn4
# Third key group
- pgp:
- fingerprint5
And then run ``sops example.json``.
The threshold (``shamir_threshold``) is set to 2, so this configuration will require
master keys from two of the three different key groups in order to decrypt the file.
You can then decrypt the file the same way as with any other SOPS file:
.. code:: bash
$ sops -d example.json
Key service
There are situations where you might want to run sops on a machine that
doesn't have direct access to encryption keys such as PGP keys. The sops key
service allows you to forward a socket so that sops can access encryption
keys stored on a remote machine. This is similar to GPG Agent, but more
portable.
SOPS uses a client-server approach to encrypting and decrypting the data key. By default, SOPS runs a local key service in-process. SOPS uses a key service client to send an encrypt or decrypt request to a key service, which then performs the operation. The requests are sent using gRPC and Protocol Buffers. The requests contain an identifier for the key they should perform the operation with, and the plaintext or encrypted data key. The requests do not contain any cryptographic keys, public or private.
WARNING: the key service connection currently does not use any sort of authentication or encryption. Therefore, it is recommended that you make sure the connection is authenticated and encrypted in some other way, for example through an SSH tunnel.
Whenever we try to encrypt or decrypt a data key, SOPS will try to do so first with the local key service (unless it's disabled), and if that fails, it will try all other remote key services until one succeeds.
You can start a key service server by running sops keyservice.
You can specify the key services the sops binary uses with --keyservice.
This flag can be specified more than once, so you can use multiple key
services. The local key service can be disabled with
enable-local-keyservice=false.
For example, to decrypt a file using both the local key service and the key
service exposed on the unix socket located in /tmp/sops.sock, you can run:
.. code:: bash
$ sops --keyservice unix:///tmp/sops.sock -d file.yaml`
And if you only want to use the key service exposed on the unix socket located
in /tmp/sops.sock and not the local key service, you can run:
.. code:: bash
$ sops --enable-local-keyservice=false --keyservice unix:///tmp/sops.sock -d file.yaml
Auditing
Sometimes, users want to be able to tell what files were accessed by whom in an
environment they control. For this reason, SOPS can generate audit logs to
record activity on encrypted files. When enabled, SOPS will write a log entry
into a pre-configured PostgreSQL database when a file is decrypted. The log
includes a timestamp, the username SOPS is running as, and the file that was
decrypted.
In order to enable auditing, you must first create the database and credentials
using the schema found in ``audit/schema.sql``. This schema defines the
tables that store the audit events and a role named ``sops`` that only has
permission to add entries to the audit event tables. The default password for
the role ``sops`` is ``sops``. You should change this password.
Once you have created the database, you have to tell SOPS how to connect to it.
Because we don't want users of SOPS to be able to control auditing, the audit
configuration file location is not configurable, and must be at
``/etc/sops/audit.yaml``. This file should have strict permissions such
that only the root user can modify it.
For example, to enable auditing to a PostgreSQL database named ``sops`` running
on localhost, using the user ``sops`` and the password ``sops``,
``/etc/sops/audit.yaml`` should have the following contents:
.. code:: yaml
backends:
postgres:
- connection_string: "postgres://sops:sops@localhost/sops?sslmode=verify-full"
You can find more information on the ``connection_string`` format in the
`PostgreSQL docs <https://www.postgresql.org/docs/current/static/libpq-connect.html#libpq-connstring>`_.
Under the ``postgres`` map entry in the above YAML is a list, so one can
provide more than one backend, and SOPS will log to all of them:
.. code:: yaml
backends:
postgres:
- connection_string: "postgres://sops:sops@localhost/sops?sslmode=verify-full"
- connection_string: "postgres://sops:sops@remotehost/sops?sslmode=verify-full"
Saving Output to a File
By default sops just dumps all the output to the standard output. We can use the
--output flag followed by a filename to save the output to the file specified.
Beware using both --in-place and --output flags will result in an error.
YAML and JSON type extensions
``sops`` uses the file extension to decide which encryption method to use on the file
content. ``YAML``, ``JSON``, ``ENV``, and ``INI`` files are treated as trees of data, and key/values are
extracted from the files to only encrypt the leaf values. The tree structure is also
used to check the integrity of the file.
Therefore, if a file is encrypted using a specific format, it need to be decrypted
in the same format. The easiest way to achieve this is to conserve the original file
extension after encrypting a file. For example:
.. code:: bash
$ sops -e -i myfile.json
$ sops -d myfile.json
If you want to change the extension of the file once encrypted, you need to provide
sops with the ``--input-type`` flag upon decryption. For example:
.. code:: bash
$ sops -e myfile.json > myfile.json.enc
$ sops -d --input-type json myfile.json.enc
YAML anchors
~~~~~~~~~~~~
``sops`` only supports a subset of ``YAML``'s many types. Encrypting YAML files that
contain strings, numbers and booleans will work fine, but files that contain anchors
will not work, because the anchors redefine the structure of the file at load time.
This file will not work in ``sops``:
.. code:: yaml
bill-to: &id001
street: |
123 Tornado Alley
Suite 16
city: East Centerville
state: KS
ship-to: *id001
``sops`` uses the path to a value as additional data in the AEAD encryption, and thus
dynamic paths generated by anchors break the authentication step.
JSON and TEXT file types do not support anchors and thus have no such limitation.
YAML Streams
~~~~~~~~~~~~
``YAML`` supports having more than one "document" in a single file, while
formats like ``JSON`` do not. ``sops`` is able to handle both. This means the
following multi-document will be encrypted as expected:
.. code:: yaml
---
data: foo
---
data: bar
Note that the ``sops`` metadata, i.e. the hash, etc, is computed for the physical
file rather than each internal "document".
Top-level arrays
~~~~~~~~~~~~~~~~
``YAML`` and ``JSON`` top-level arrays are not supported, because ``sops``
needs a top-level ``sops`` key to store its metadata.
This file will not work in sops:
.. code:: yaml
---
- some
- array
- elements
But this one will because because the ``sops`` key can be added at the same level as the
``data`` key.
.. code:: yaml
data:
- some
- array
- elements
Similarly, with ``JSON`` arrays, this document will not work:
.. code:: json
[
"some",
"array",
"elements"
]
But this one will work just fine:
.. code:: json
{
"data": [
"some",
"array",
"elements"
]
}
Examples
--------
Take a look into the `examples <https://github.com/mozilla/sops/tree/master/examples>`_ folder for detailed use cases of sops in a CI environment. The section below describes specific tips for common use cases.
Creating a new file
~~~~~~~~~~~~~~~~~~~
The command below creates a new file with a data key encrypted by KMS and PGP.
.. code:: bash
$ sops --kms "arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500" --pgp C9CAB0AF1165060DB58D6D6B2653B624D620786D /path/to/new/file.yaml
Encrypting an existing file
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Similar to the previous command, we tell sops to use one KMS and one PGP key.
The path points to an existing cleartext file, so we give sops flag ``-e`` to
encrypt the file, and redirect the output to a destination file.
.. code:: bash
$ export SOPS_KMS_ARN="arn:aws:kms:us-west-2:927034868273:key/fe86dd69-4132-404c-ab86-4269956b4500"
$ export SOPS_PGP_FP="C9CAB0AF1165060DB58D6D6B2653B624D620786D"
$ sops -e /path/to/existing/file.yaml > /path/to/new/encrypted/file.yaml
Decrypt the file with ``-d``.
.. code:: bash
$ sops -d /path/to/new/encrypted/file.yaml
Encrypt or decrypt a file in place
Rather than redirecting the output of -e or -d, sops can replace the
original file after encrypting or decrypting it.
.. code:: bash
# file.yaml is in cleartext
$ sops -e -i /path/to/existing/file.yaml
# file.yaml is now encrypted
$ sops -d -i /path/to/existing/file.yaml
# file.yaml is back in cleartext
Encrypting binary files
``sops`` primary use case is encrypting YAML and JSON configuration files, but it
also has the ability to manage binary files. When encrypting a binary, sops will
read the data as bytes, encrypt it, store the encrypted base64 under
``tree['data']`` and write the result as JSON.
Note that the base64 encoding of encrypted data can actually make the encrypted
file larger than the cleartext one.
In-place encryption/decryption also works on binary files.
.. code::
$ dd if=/dev/urandom of=/tmp/somerandom bs=1024
count=512
512+0 records in
512+0 records out
524288 bytes (524 kB) copied, 0.0466158 s, 11.2 MB/s
$ sha512sum /tmp/somerandom
9589bb20280e9d381f7a192000498c994e921b3cdb11d2ef5a986578dc2239a340b25ef30691bac72bdb14028270828dad7e8bd31e274af9828c40d216e60cbe /tmp/somerandom
$ sops -e -i /tmp/somerandom
please wait while a data encryption key is being generated and stored securely
$ sops -d -i /tmp/somerandom
$ sha512sum /tmp/somerandom
9589bb20280e9d381f7a192000498c994e921b3cdb11d2ef5a986578dc2239a340b25ef30691bac72bdb14028270828dad7e8bd31e274af9828c40d216e60cbe /tmp/somerandom
Extract a sub-part of a document tree
sops can extract a specific part of a YAML or JSON document, by provided the
path in the --extract command line flag. This is useful to extract specific
values, like keys, without needing an extra parser.
.. code:: bash
$ sops -d --extract '["app2"]["key"]' ~/git/svc/sops/example.yaml
-----BEGIN RSA PRIVATE KEY-----
MIIBPAIBAAJBAPTMNIyHuZtpLYc7VsHQtwOkWYobkUblmHWRmbXzlAX6K8tMf3Wf
ImcbNkqAKnELzFAPSBeEMhrBN0PyOC9lYlMCAwEAAQJBALXD4sjuBn1E7Y9aGiMz
bJEBuZJ4wbhYxomVoQKfaCu+kH80uLFZKoSz85/ySauWE8LgZcMLIBoiXNhDKfQL
vHECIQD6tCG9NMFWor69kgbX8vK5Y+QL+kRq+9HK6yZ9a+hsLQIhAPn4Ie6HGTjw
fHSTXWZpGSan7NwTkIu4U5q2SlLjcZh/AiEA78NYRRBwGwAYNUqzutGBqyXKUl4u
Erb0xAEyVV7e8J0CIQC8VBY8f8yg+Y7Kxbw4zDYGyb3KkXL10YorpeuZR4LuQQIg
bKGPkMM4w5blyE1tqGN0T7sJwEx+EUOgacRNqM2ljVA=
-----END RSA PRIVATE KEY-----
The tree path syntax uses regular python dictionary syntax, without the variable name. Extract keys by naming them, and array elements by numbering them.
.. code:: bash
$ sops -d --extract '["an_array"][1]' ~/git/svc/sops/example.yaml
secretuser2
Set a sub-part in a document tree
``sops`` can set a specific part of a YAML or JSON document, by providing
the path and value in the ``--set`` command line flag. This is useful to
set specific values, like keys, without needing an editor.
.. code:: bash
$ sops --set '["app2"]["key"] "app2keystringvalue"' ~/git/svc/sops/example.yaml
The tree path syntax uses regular python dictionary syntax, without the
variable name. Set to keys by naming them, and array elements by
numbering them.
.. code:: bash
$ sops --set '["an_array"][1] "secretuser2"' ~/git/svc/sops/example.yaml
The value must be formatted as json.
.. code:: bash
$ sops --set '["an_array"][1] {"uid1":null,"uid2":1000,"uid3":["bob"]}' ~/git/svc/sops/example.yaml
Using sops as a library in a python script
You can import sops as a module and use it in your python program.
.. code:: python
import sops
pathtype = sops.detect_filetype(path)
tree = sops.load_file_into_tree(path, pathtype)
sops_key, tree = sops.get_key(tree)
tree = sops.walk_and_decrypt(tree, sops_key)
sops.write_file(tree, path=path, filetype=pathtype)
Note: this uses the previous implemenation of sops written in python,
and so doesn't support newer features such as GCP-KMS.
To use the current version, call out to sops using subprocess.check_output
Showing diffs in cleartext in git
You most likely want to store encrypted files in a version controlled repository.
Sops can be used with git to decrypt files when showing diffs between versions.
This is very handy for reviewing changes or visualizing history.
To configure sops to decrypt files during diff, create a ``.gitattributes`` file
at the root of your repository that contains a filter and a command.
.. code::
*.yaml diff=sopsdiffer
Here we only care about YAML files. ``sopsdiffer`` is an arbitrary name that we map
to a sops command in the git configuration file of the repository.
.. code:: bash
$ git config diff.sopsdiffer.textconv "sops -d"
$ grep -A 1 sopsdiffer .git/config
[diff "sopsdiffer"]
textconv = "sops -d"
With this in place, calls to ``git diff`` will decrypt both previous and current
versions of the target file prior to displaying the diff. And it even works with
git client interfaces, because they call git diff under the hood!
Encrypting only parts of a file
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Note: this only works on YAML and JSON files, not on BINARY files.
By default, ``sops`` encrypts all the values of a YAML or JSON file and leaves the
keys in cleartext. In some instances, you may want to exclude some values from
being encrypted. This can be accomplished by adding the suffix **_unencrypted**
to any key of a file. When set, all values underneath the key that set the
**_unencrypted** prefix will be left in cleartext.
Note that, while in cleartext, unencrypted content is still added to the
checksum of the file, and thus cannot be modified outside of sops without
breaking the file integrity check.
The unencrypted suffix can be set to a different value using the
``--unencrypted-suffix`` option.
Conversely, you can opt in to only encrypt some values in a YAML or JSON file,
by adding a chosen suffix to those keys and passing it to the ``--encrypted-suffix`` option.
You can also specify these options in the ``.sops.yaml`` config file.
Note: these two options ``--unencrypted-suffix`` and ``--encrypted-suffix`` are mutually exclusive and
cannot both be used in the same file.
Encryption Protocol
-------------------
When sops creates a file, it generates a random 256 bit data key and asks each
KMS and PGP master key to encrypt the data key. The encrypted version of the data
key is stored in the ``sops`` metadata under ``sops.kms`` and ``sops.pgp``.
For KMS:
.. code:: yaml
sops:
kms:
- enc: CiC6yCOtzsnFhkfdIslYZ0bAf//gYLYCmIu87B3sy/5yYxKnAQEBAQB4usgjrc7JxYZH3SLJWGdGwH//4GC2ApiLvOwd7Mv+cmMAAAB+MHwGCSqGSIb3DQEHBqBvMG0CAQAwaAYJKoZIhvcNAQcBMB4GCWCGSAFlAwQBLjARBAyGdRODuYMHbA8Ozj8CARCAO7opMolPJUmBXd39Zlp0L2H9fzMKidHm1vvaF6nNFq0ClRY7FlIZmTm4JfnOebPseffiXFn9tG8cq7oi
enc_ts: 1439568549.245995
arn: arn:aws:kms:us-east-1:656532927350:key/920aff2e-c5f1-4040-943a-047fa387b27e
For PGP:
.. code:: yaml
sops:
pgp:
- fp: 85D77543B3D624B63CEA9E6DBC17301B491B3F21
created_at: 1441570391.930042
enc: |
-----BEGIN PGP MESSAGE-----
Version: GnuPG v1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=
=oJgS
-----END PGP MESSAGE-----
``sops`` then opens a text editor on the newly created file. The user adds data to the
file and saves it when done.
Upon save, sops browses the entire file as a key/value tree. Every time sops
encounters a leaf value (a value that does not have children), it encrypts the
value with AES256_GCM using the data key and a 256 bit random initialization
vector.
Each file uses a single data key to encrypt all values of a document, but each
value receives a unique initialization vector and has unique authentication data.
Additional data is used to guarantee the integrity of the encrypted data
and of the tree structure: when encrypting the tree, key names are concatenated
into a byte string that is used as AEAD additional data (aad) when encrypting
values. We expect that keys do not carry sensitive information, and
keeping them in cleartext allows for better diff and overall readability.
Any valid KMS or PGP master key can later decrypt the data key and access the
data.
Multiple master keys allow for sharing encrypted files without sharing master
keys, and provide a disaster recovery solution. The recommended way to use sops
is to have two KMS master keys in different regions and one PGP public key with
the private key stored offline. If, by any chance, both KMS master keys are
lost, you can always recover the encrypted data using the PGP private key.
Message Authentication Code
~~~~~~~~~~~~~~~~~~~~~~~~~~~
In addition to authenticating branches of the tree using keys as additional
data, sops computes a MAC on all the values to ensure that no value has been
added or removed fraudulently. The MAC is stored encrypted with AES_GCM and
the data key under tree->`sops`->`mac`.
Motivation
----------
Automating the distribution of secrets and credentials to components of an
infrastructure is a hard problem. We know how to encrypt secrets and share them
between humans, but extending that trust to systems is difficult. Particularly
when these systems follow devops principles and are created and destroyed
without human intervention. The issue boils down to establishing the initial
trust of a system that just joined the infrastructure, and providing it access
to the secrets it needs to configure itself.
The initial trust
~~~~~~~~~~~~~~~~~
In many infrastructures, even highly dynamic ones, the initial trust is
established by a human. An example is seen in Puppet by the way certificates are
issued: when a new system attempts to join a Puppetmaster, an administrator
must, by default, manually approve the issuance of the certificate the system
needs. This is cumbersome, and many puppetmasters are configured to auto-sign
new certificates to work around that issue. This is obviously not recommended
and far from ideal.
AWS provides a more flexible approach to trusting new systems. It uses a
powerful mechanism of roles and identities. In AWS, it is possible to verify
that a new system has been granted a specific role at creation, and it is
possible to map that role to specific resources. Instead of trusting new systems
directly, the administrator trusts the AWS permission model and its automation
infrastructure. As long as AWS keys are safe, and the AWS API is secure, we can
assume that trust is maintained and systems are who they say they are.
KMS, Trust and secrets distribution
Using the AWS trust model, we can create fine grained access controls to Amazon's Key Management Service (KMS). KMS is a service that encrypts and decrypts data with AES_GCM, using keys that are never visible to users of the service. Each KMS master key has a set of role-based access controls, and individual roles are permitted to encrypt or decrypt using the master key. KMS helps solve the problem of distributing keys, by shifting it into an access control problem that can be solved using AWS's trust model.
Operational requirements
When Mozilla's Services Operations team started revisiting the issue of
distributing secrets to EC2 instances, we set a goal to store these secrets
encrypted until the very last moment, when they need to be decrypted on target
systems. Not unlike many other organizations that operate sufficiently complex
automation, we found this to be a hard problem with a number of prerequisites:
1. Secrets must be stored in YAML files for easy integration into hiera
2. Secrets must be stored in GIT, and when a new CloudFormation stack is
built, the current HEAD is pinned to the stack. (This allows secrets to
be changed in GIT without impacting the current stack that may
autoscale).
3. Entries must be encrypted separately. Encrypting entire files as blobs makes
git conflict resolution almost impossible. Encrypting each entry
separately is much easier to manage.
4. Secrets must always be encrypted on disk (admin laptop, upstream
git repo, jenkins and S3) and only be decrypted on the target
systems
SOPS can be used to encrypt YAML, JSON and BINARY files. In BINARY mode, the
content of the file is treated as a blob, the same way PGP would encrypt an
entire file. In YAML and JSON modes, however, the content of the file is
manipulated as a tree where keys are stored in cleartext, and values are
encrypted. hiera-eyaml does something similar, and over the years we learned
to appreciate its benefits, namely:
* diffs are meaningful. If a single value of a file is modified, only that
value will show up in the diff. The diff is still limited to only showing
encrypted data, but that information is already more granular that
indicating that an entire file has changed.
* conflicts are easier to resolve. If multiple users are working on the
same encrypted files, as long as they don't modify the same values,
changes are easy to merge. This is an improvement over the PGP
encryption approach where unsolvable conflicts often happen when
multiple users work on the same file.
OpenPGP integration
~~~~~~~~~~~~~~~~~~~
OpenPGP gets a lot of bad press for being an outdated crypto protocol, and while
true, what really made us look for alternatives is the difficulty of managing and
distributing keys to systems. With KMS, we manage permissions to an API, not keys,
and that's a lot easier to do.
But PGP is not dead yet, and we still rely on it heavily as a backup solution:
all our files are encrypted with KMS and with one PGP public key, with its
private key stored securely for emergency decryption in the event that we lose
all our KMS master keys.
SOPS can be used without KMS entirely, the same way you would use an encrypted
PGP file: by referencing the pubkeys of each individual who has access to the file.
It can easily be done by providing sops with a comma-separated list of public keys
when creating a new file:
.. code:: bash
$ sops --pgp "E60892BB9BD89A69F759A1A0A3D652173B763E8F,84050F1D61AF7C230A12217687DF65059EF093D3,85D77543B3D624B63CEA9E6DBC17301B491B3F21" mynewfile.yaml
Threat Model
------------
The security of the data stored using sops is as strong as the weakest
cryptographic mechanism. Values are encrypted using AES256_GCM which is the
strongest symmetric encryption algorithm known today. Data keys are encrypted
in either KMS, which also uses AES256_GCM, or PGP which uses either RSA or
ECDSA keys.
Going from the most likely to the least likely, the threats are as follows:
Compromised AWS credentials grant access to KMS master key
An attacker with access to an AWS console can grant itself access to one of the KMS master keys used to encrypt a sops data key. This threat should be mitigated by protecting AWS accesses with strong controls, such as multi-factor authentication, and also by performing regular audits of permissions granted to AWS users.
Compromised PGP key
PGP keys are routinely mishandled, either because owners copy them from
machine to machine, or because the key is left forgotten on an unused machine
an attacker gains access to. When using PGP encryption, sops users should take
special care of PGP private keys, and store them on smart cards or offline
as often as possible.
Factorized RSA key
~~~~~~~~~~~~~~~~~~
sops doesn't apply any restriction on the size or type of PGP keys. A weak PGP
keys, for example 512 bits RSA, could be factorized by an attacker to gain
access to the private key and decrypt the data key. Users of sops should rely
on strong keys, such as 2048+ bits RSA keys, or 256+ bits ECDSA keys.
Weak AES cryptography
A vulnerability in AES256_GCM could potentially leak the data key or the KMS master key used by a sops encrypted file. While no such vulnerability exists today, we recommend that users keep their encrypted files reasonably private.
sops will remain backward compatible on the major version, meaning that all
improvements brought to the 1.X and 2.X branches (current) will maintain the
file format introduced in 1.0.
Please report security issues to jvehent at mozilla dot com, or by using one
of the contact method available on keybase: https://keybase.io/jvehent <https://keybase.io/jvehent>_
Mozilla Public License Version 2.0
The core team is composed of:
And a whole bunch of contributors <https://github.com/mozilla/sops/graphs/contributors>_
sops was inspired by hiera-eyaml <https://github.com/TomPoulton/hiera-eyaml>,
credstash <https://github.com/LuminalOSS/credstash> ,
sneaker <https://github.com/codahale/sneaker>,
password store <http://www.passwordstore.org/> and too many years managing
PGP encrypted files by hand...
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