minio/docs/sts/opa.md
Harshavardhana 54ae364def Introduce STS client grants API and OPA policy integration (#6168)
This PR introduces two new features

- AWS STS compatible STS API named AssumeRoleWithClientGrants

```
POST /?Action=AssumeRoleWithClientGrants&Token=<jwt>
```

This API endpoint returns temporary access credentials, access
tokens signature types supported by this API

  - RSA keys
  - ECDSA keys

Fetches the required public key from the JWKS endpoints, provides
them as rsa or ecdsa public keys.

- External policy engine support, in this case OPA policy engine

- Credentials are stored on disks
2018-10-09 14:00:01 -07:00

86 lines
3.1 KiB
Markdown

# OPA Quickstart Guide [![Slack](https://slack.minio.io/slack?type=svg)](https://slack.minio.io)
OPA is a lightweight general-purpose policy engine that can be co-located with Minio server, in this document we talk about how to use OPA HTTP API to authorize Minio STS credentials.
## Get started
### 1. Prerequisites
- Docker 18.03 or above, refer here for [installation](https://docs.docker.com/install/).
- Docker compose 1.20 or above, refere here for [installation](https://docs.docker.com/compose/install/#prerequisites).
### 2. Start OPA
First, create a `docker-compose.yml` file that runs OPA and the demo web server.
```
cat >docker-compose.yml <<EOF
version: '2'
services:
opa:
image: openpolicyagent/opa:0.9.1
ports:
- 8181:8181
command:
- "run"
- "--server"
- "--log-level=debug"
api_server:
image: openpolicyagent/demo-restful-api:0.2
ports:
- 5000:5000
environment:
- OPA_ADDR=http://opa:8181
- POLICY_PATH=/v1/data/httpapi/authz
EOF
```
Then run `docker-compose` to pull and run the containers.
```
docker-compose -f docker-compose.yml up
```
### 3. Create new OPA Policy
In another terminal, create a policy that allows users to upload objects
```
cat > putobject.rego <<EOF
package httpapi.authz
import input as http_api
allow {
input.action = "s3:PutObject"
input.owner = false
}
EOF
```
Then load the policy via OPA's REST API.
```
curl -X PUT --data-binary @putobject.rego \
localhost:8181/v1/policies/putobject
```
### 4. Setup Minio with OPA
Minio server expects environment variable for OPA http API url as `MINIO_IAM_OPA_URL`, this environment variable takes a single entry.
```
export MINIO_IAM_OPA_URL=http://localhost:8181/v1/data/httpapi/authz
minio server /mnt/data
```
### 5. Test with Minio STS API
Assuming that Minio server is configured to support STS API by following the doc [Minio STS Quickstart Guide](https://docs.minio.io/docs/minio-sts-quickstart-guide), execute the following command to temporary credentials from Minio server.
```
go run full-example.go -cid PoEgXP6uVO45IsENRngDXj5Au5Ya -csec eKsw6z8CtOJVBtrOWvhRWL4TUCga
##### Credentials
{
"accessKey": "IRBLVDGN5QGMDCMO1X8V",
"secretKey": "KzS3UZKE7xqNdtRbKyfcWgxBS6P1G4kwZn4DXKuY",
"expiration": "2018-08-21T15:49:38-07:00",
"sessionToken": "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJhY2Nlc3NLZXkiOiJJUkJMVkRHTjVRR01EQ01PMVg4ViIsImF1ZCI6IlBvRWdYUDZ1Vk80NUlzRU5SbmdEWGo1QXU1WWEiLCJhenAiOiJQb0VnWFA2dVZPNDVJc0VOUm5nRFhqNUF1NVlhIiwiZXhwIjoxNTM0ODkxNzc4LCJpYXQiOjE1MzQ4ODgxNzgsImlzcyI6Imh0dHBzOi8vbG9jYWxob3N0Ojk0NDMvb2F1dGgyL3Rva2VuIiwianRpIjoiMTg0NDMyOWMtZDY1YS00OGEzLTgyMjgtOWRmNzNmZTgzZDU2In0.4rKsZ8VkZnIS_ALzfTJ9UbEKPFlQVvIyuHw6AWTJcDFDVgQA2ooQHmH9wUDnhXBi1M7o8yWJ47DXP-TLPhwCgQ"
}
```
These credentials can now be used to perform Minio API operations, these credentials automatically expire in 1hr. To understand more about credential expiry duration and client grants STS API read further [here](https://docs.minio.io/docs/api-assume-role-with-client-grants).
## Explore Further
- [Minio STS Quickstart Guide](https://docs.minio.io/docs/minio-sts-quickstart-guide)
- [The Minio documentation website](https://docs.minio.io)