AWS SigV4 Proxy

The AWS SigV4 Proxy will sign incoming HTTP requests and forward them to the host specified in the Host header.

You can strip out arbirtary headers from the incoming request by using the -s option.

Getting Started

Build and run the Proxy

The proxy uses the default AWS SDK for Go credential search path:

* Environment variables.
* Shared credentials file.
* IAM role for Amazon EC2 or ECS task role

More information can be found in the [developer guide](https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html)

docker build -t aws-sigv4-proxy .

# Env vars
docker run --rm -ti \
  -e 'AWS_ACCESS_KEY_ID=<YOUR ACCESS KEY ID>' \
  -e 'AWS_SECRET_ACCESS_KEY=<YOUR SECRET ACCESS KEY>' \
  -p 8080:8080 \
  aws-sigv4-proxy -v

# Shared Credentials
docker run --rm -ti \
  -v ~/.aws:/root/.aws \
  -p 8080:8080 \
  -e 'AWS_SDK_LOAD_CONFIG=true' \
  -e 'AWS_PROFILE=<SOME PROFILE>' \
  aws-sigv4-proxy -v

Configuration

When running the Proxy, the following flags can be used (none are required) :

Flag (or short form)	Type	Description	Default
verbose or v	Boolean	Enable additional logging, implies all the log-* options	False
log-failed-requests	Boolean	Log 4xx and 5xx response body	False
log-signing-process	Boolean	Log sigv4 signing process	False
unsigned-payload	Boolean	Prevent signing of the payload"	False
port	String	Port to serve http on	8080
strip or s	String	Headers to strip from incoming request	None
duplicate-headers	String	Duplicate headers to an X-Original- prefix name	None
role-arn	String	Amazon Resource Name (ARN) of the role to assume	None
name	String	AWS Service to sign for	None
sign-host	String	Host to sign for	None
host	String	Host to proxy to	None
region	String	AWS region to sign for	None
upstream-url-scheme	String	Protocol to proxy with	https
no-verify-ssl	Boolean	Disable peer SSL certificate validation	False
transport.idle-conn-timeout	Duration	Idle timeout to the upstream service	40s

Examples

S3

# us-east-1
curl -s -H 'host: s3.amazonaws.com' http://localhost:8080/<BUCKET_NAME>

# other region
curl -s -H 'host: s3.<BUCKET_REGION>.amazonaws.com' http://localhost:8080/<BUCKET_NAME>

SQS

curl -s -H 'host: sqs.<AWS_REGION>.amazonaws.com' 'http://localhost:8080/<AWS_ACCOUNT_ID>/<QUEUE_NAME>?Action=SendMessage&MessageBody=example'

API Gateway

curl -H 'host: <REST_API_ID>.execute-api.<AWS_REGION>.amazonaws.com' http://localhost:8080/<STAGE>/<PATH>

Running the service and stripping out sigv2 authorization headers

docker run --rm -ti \
  -v ~/.aws:/root/.aws \
  -p 8080:8080 \
  -e 'AWS_SDK_LOAD_CONFIG=true' \
  -e 'AWS_PROFILE=<SOME PROFILE>' \
  aws-sigv4-proxy -v -s Authorization

Running the service and preserving the original Authorization header as X-Original-Authorization (useful because Authorization header will be overwritten.)

docker run --rm -ti \
  -v ~/.aws:/root/.aws \
  -p 8080:8080 \
  -e 'AWS_SDK_LOAD_CONFIG=true' \
  -e 'AWS_PROFILE=<SOME PROFILE>' \
  aws-sigv4-proxy -v --duplicate-headers Authorization

Running the service with Assume Role to use temporary credentials

docker run --rm -ti \
  -v ~/.aws:/root/.aws \
  -p 8080:8080 \
  -e 'AWS_SDK_LOAD_CONFIG=true' \
  -e 'AWS_PROFILE=<SOME PROFILE>' \
  aws-sigv4-proxy -v --role-arn <ARN OF ROLE TO ASSUME>

Include service name & region overrides when you notice errors like unable to determine service from host for API gateway, for example.

docker run --rm -ti \
  -v ~/.aws:/root/.aws \
  -p 8080:8080 \
  -e 'AWS_SDK_LOAD_CONFIG=true' \
  -e 'AWS_PROFILE=<SOME PROFILE>' \
  aws-sigv4-proxy -v --name execute-api --region us-east-1

OpenSearch

• Access AWS OpenSearch domain, hosted in private subnet of AWS VPC, with access policy restricted to IAM role.

  Prepare connection (assume role, export AWS_PROFILE, run ssh tunnel):

  aws sts assume-role \
   --role-arn "arn:aws:iam::123456789012:role/example-role" \
   --role-session-name role-profile
  export AWS_PROFILE=role-profile
  
  ssh \
   -4 \
   -o BatchMode="yes" \
   -o StrictHostKeyChecking="no" \
   -o ProxyCommand="aws ssm start-session --target %h --region eu-west-1 --document-name AWS-StartSSHSession --parameters portNumber=%p" \
   -i /Users/user/.ssh/id_rsa ubuntu@i-bastion-host \
   -L 4443:vpc-private-domain-name.eu-west-1.es.amazonaws.com:443 \
   -N

  Finally, run proxy:

  docker run --rm -ti \
       -v ~/.aws:/root/.aws \
       --network=bridge \
       -p 8080:8080 \
       -e "AWS_SDK_LOAD_CONFIG=true" \
       -e "AWS_PROFILE=role-profile" \
       aws-sigv4-proxy \
               --verbose --log-failed-requests --log-signing-process --no-verify-ssl \
               --name es --region eu-west-1 \
               --host host.docker.internal:4443 \
               --sign-host eu-west-1.es.amazonaws.com

  Access dashboard via http://localhost:8080/_dashboards/app/home#/tutorial_directory

Reference

• AWS SigV4 Signing Docs
• AWS SigV4 Admission Controller - Used to install the AWS SigV4 Proxy as a sidecar

License

This library is licensed under the Apache 2.0 License.