Limes provides an easy work flow with MFA protected access keys, temporary credentials and access to multiple roles/accounts.
Limes is the Local Instance MEtadata Service and emulates parts of the AWS Instance Metadata Service running on Amazon Linux. The AWS SDK and AWS CLI can therefor utilize this service to authenticate.
The AWS SDK refreshes credentials automatically when using limes. So all services will change profile if the profile is changed in limes.
- Download binary for your architecture from https://github.com/otm/limes/releases/latest
- Copy the file to
/usr/local/binor appropriate location in PATH - Make it executable:
chmod +x /usr/local/bin/limes - Linux: Allow limes to bind to privileged ports
setcap 'cap_net_bind_service=+ep' /usr/local/bin/limes
Note: On Mac OS limes server is needed to run as root for the time being.
The configuration below adds the necessary IP configuration on the loop back device. Without this configuration the service can not start.
Note: This configuration is not persistent between reboots.
sudo ip addr add 169.254.169.254/24 broadcast 169.254.169.255 dev lo:metadata
sudo ip link set dev lo:metadata up
sudo /sbin/ifconfig lo0 alias 169.254.169.254
wget -O /etc/bash_completion.d/limes https://raw.githubusercontent.com/otm/limes/master/assets/limes
wget -O $(brew --prefix)/etc/bash_completion.d/limes https://raw.githubusercontent.com/otm/limes/master/assets/limes
There is currently a bug in the completer for the AWS CLI that makes it misbehave when used with _command_offset. This can be solved by adding a secondary completion entry for the AWS CLI. To make this persistent add it to your bash configuration.
Linux
complete -C '/usr/local/bin/aws_completer' limes run aws
Mac (Brew)
complete -C "$(brew --prefix)/bin/aws_completer" limes run aws
To be done
There is an example configuration file. The configuration file is documented. Make a copy of the file and place it in ~/.limes/config.
mkdir -p ~/.limes
wget -O ~/.limes/config https://raw.githubusercontent.com/otm/limes/master/config.example
Use your favorite text editor to update ~/.limes/config
Running limes in your terminal prints usage information.
The service is started with limes start.
A profile is assumed with limes assume <profile-name>, where profile-name is a configured profile. Please note that this does not refer to AWS profiles but profiles configured in limes.
If you have assumed a role on limes you might want to run an application once with an alternate profile. This is possible without assuming the profile with the run subcommand.
limes --profile <name> run <application> [args...]
Tip
With limes --profile <name> run bash it is possible to quickly start a shell with exported environment variables that is valid for an hour.
By adding protected: true to your profile it will not be possible to assume that role. It will only be possible to utilize the subcommands run and env.
By running limes status it is possible to see the current status, and also it can detect common problems and misconfiguration.
If AWS environment variables, .aws/credentials or .aws/config are present there is a chance that the limes does not work. This can be checked with limes status.
The service should be configured on the loop back device, and only accessible from the host it is running on.
Note: It is important not to run any service that could forwards request on the host running Limes as this would be a security risk. However, this is no difference from the setup on an Amazon Linux instance in AWS. If an attacker could forward requests to 169.254.169.254/24 your credentials could be compromised. Please note that an attacker could utilize a DNS to resolve to this address, so always be aware where you forward requests to.
- Windows support (If I get someone to test it)
To build you need a Go compiler and environment setup. See https://golang.org/ for more information regarding setting up and configuring Go.
go get github.com/otm/limes
go build
If protobuf definitions are updated protoc is needed on the system. Installation instructions are available at https://github.com/google/protobuf. Ẅhen protoc is installed run go generate. Currently build with libprotoc 3.1.0.
go get -u github.com/golang/protobuf/{proto,protoc-gen-go}
go generate