# README
Limes
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.
Warning
The AWS SDK refreshes credentials automatically when using limes. So all services will change profile if the profile is changed in limes.
Installation
- 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.
Configuring the Loop Back Device
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.
Linux
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
Mac
sudo /sbin/ifconfig lo0 alias 169.254.169.254
Bash Completion
Linux:
wget -O /etc/bash_completion.d/limes https://raw.githubusercontent.com/otm/limes/master/assets/limes
Mac
wget -O $(brew --prefix)/etc/bash_completion.d/limes https://raw.githubusercontent.com/otm/limes/master/assets/limes
Fixing Completion for AWS CLI
There is currently a bug in the completer for the AWS CLI that makes it misbehave when used with _command_offset. This can be solved by adding a secondary completion entry for the AWS CLI. To make this persistent add it to your bash configuration.
Linux
complete -C '/usr/local/bin/aws_completer' limes run aws
Mac (Brew)
complete -C "$(brew --prefix)/bin/aws_completer" limes run aws
Configuring IAM (Identity and Access Management)
To be done
Configuring IMS (Instance Meta-data Service)
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
Usage
Running limes in your terminal prints usage information.
Starting the Service
The service is started with limes start.
Assuming Profiles
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.
Running Applications with Alternate Profile
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.
Protected Profiles
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.
Service Status
By running limes status it is possible to see the current status, and also it can detect common problems and misconfiguration.
Known Problems
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.
Security
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.
Roadmap
- Windows support (If I get someone to test it)
Build
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 run:
go generate