17 Security Overview
chrislu edited this page 2022-07-29 01:40:03 -07:00

Overview

Since SeaweedFS is a distributed system with many volume servers, the volume servers have the risk of being changed without proper access control. We want to have the freedom to place a volume server anywhere we want, with the confidence that nobody can tamper the data.

We will address the volume servers first. The following items are not covered, yet:

  • master server http REST services

Starting with version 2.84, the Filer HTTP REST services can be secured with a JWT, by setting jwt.filer_signing.key and jwt.filer_signing.read.key in security.toml.

In summary, here are what can be achieved.

Server Service Note
master gRPC secured by mutual TLS
volume gRPC secured by mutual TLS
filer gRPC secured by mutual TLS
master http "weed master -disableHttp", disable http operations, only gRPC operations are allowed.
filer http Before version 2.84: "weed filer -disableHttp", disable http operations, only gRPC operations are allowed. This works with "weed mount" by FUSE. It does not work with the [S3 Gateway](Amazon S3 API), as this does HTTP calls to the Filer.

Starting with version 2.84: secured by JWT, by setting jwt.filer_signing.key and jwt.filer_signing.read.key in security.toml. This now works with the Amazon S3 API.
volume http write set jwt.signing.key in security.toml in master and volume servers to check token for write operations
volume http read unprotected, but url is not guessable

Generate security.toml file

See Security Configuration

Servers in SeaweedFS usually support 2 kinds of operations: gRPC and REST.

Securing gRPC operations

The following operations are implemented via gRPC.

  • requests from filer to master
  • requests from master to volume servers
  • delete operations from filer or other clients (mount, s3, filer.copy, filer.replicate, etc) to volume servers
  • requests from clients to filer

All gRPC operations can optionally be secured via mutual TLS, by customizing the security.toml file. See Security Configuration.

Securing Volume Servers

Besides gRPC mentioned above, volume servers can only be changed by file upload, update, and delete operations. Json Web Token (JWT) is used to authorize access for each file id.

JWT-based access control

To enable JWT-based access control,

  1. generate security.toml file by weed scaffold -config=security
  2. set jwt.signing.key to a secret string
  3. copy the same security.toml file to the masters and all volume servers.

Re-enabling Volume UI

By default, if the jwt.signing.key is set, the web UI on the volume servers is disabled. You can re-enable the web UI by setting access.ui=true in security.toml. Despite some information leakage (as the UI is unauthenticted), this should not pose a security risk, as the UI is purely read-only.

How JWT-based access control works

  • To upload a new file, when requesting a new fileId via http://<master>:<port>/dir/assign, the master will use the jwt.signing.key to generate and sign a JWT, and set it to response header Authorization. The JWT is valid for 10 seconds.
  • To update or delete a file by fileId, the JWT can be read from the response header Authorization of http://<master>:<port>/dir/lookup?fileId=xxxxx.
  • When sending upload/update/delete HTTP operations to a volume server, the request header Authorization should be the JWT string. The operation is authorized after the volume server validates the JWT with jwt.signing.key.

JWT Summary:

  • JWT is set in /dir/assign or /dir/lookup response header Authorization
  • JWT is read from request header Authorization
  • JWT is valid for 10 seconds.
  • JWT only has permission to create/modify/delete one fileId.
  • The volume server HTTP access is only for read, and only if the fileId is known. There are no way to iterate all files.
  • All other volume server HTTP accesses are disabled when jwt.signing is enabled.

JWT for Read Access Control

The volume server can also check JWT for reads. This mode does not work with weed filer. But this could be useful if the volume server is exposed to public and you do not want anyone to access it with a URL, e.g., paid content.

  • To enable it, set the jwt.signing.read.key in security.toml file.
  • To obtain a JWT for read, the JWT can be read from the response header Authorization of http://<master>:<port>/dir/lookup?fileId=xxxxx&read=yes.

Securing Filer HTTP with JWT

To enable JWT-based access control for the Filer,

  1. generate security.toml file by weed scaffold -config=security
  2. set jwt.filer_signing.key to a secret string - and optionally jwt.filer_signing.read.key as well to a secret string
  3. copy the same security.toml file to the filers and all S3 proxies.

If jwt.filer_signing.key is configured: When sending upload/update/delete HTTP operations to a filer server, the request header Authorization should be the JWT string (Authorization: Bearer [JwtToken]). The operation is authorized after the filer validates the JWT with jwt.filer_signing.key.

The JwtToken can be generated by calling security.GenJwtForFilerServer(signingKey SigningKey, expiresAfterSec int) in github.com/seaweedfs/seaweedfs/weed/security package. 9b94177380/weed/security/jwt.go (L53)

If jwt.filer_signing.read.key is configured: When sending GET or HEAD requests to a filer server, the request header Authorization should be the JWT string (Authorization: Bearer [JwtToken]). The operation is authorized after the filer validates the JWT with jwt.filer_signing.read.key.

The S3 API Gateway reads the above JWT keys and sends authenticated HTTP requests to the filer.