What permissions do I add in AWS to enable ecr:getAuthorizationToken? - amazon-web-services

Question

I'm trying to follow the steps to use amazon elastic container registry (ECR) but I'm stuck at the first step, which is obtaining an auth token.
Command:
aws ecr get-login
Or...
aws ecr get-login --region=us-west-2
Error:
An error occurred (AccessDeniedException) when calling the GetAuthorizationToken operation: User: arn:aws:iam::9#####4:user/### is not authorized to perform: ecr:GetAuthorizationToken on resource: *
AWS Permissions on user for region us-west-2:
AmazonEC2FullAccess
AmazonEC2ContainerRegistryFullAccess
Billing
AdministratorAccess
AmazonECS_FullAccess
AWS CLI version:
aws help --version
aws-cli/1.14.40 Python/3.6.4 Darwin/18.2.0 botocore/1.8.44

Answer 1

Please note that you're not allowing your user any access to ECR in a sense.
Try adding the following policy to the user:
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Action": [
"ecr:GetAuthorizationToken",
"ecr:BatchCheckLayerAvailability",
"ecr:GetDownloadUrlForLayer",
"ecr:GetRepositoryPolicy",
"ecr:DescribeRepositories",
"ecr:ListImages",
"ecr:DescribeImages",
"ecr:BatchGetImage"
],
"Resource": "*"
}]
}
https://docs.aws.amazon.com/AmazonECR/latest/userguide/ecr_managed_policies.html#AmazonEC2ContainerRegistryReadOnly

Answer 2

As general advice, ecr:GetAuthorizationToken must apparently be applied to all resources * but all other ECR permissions can be scoped. When setting up ECR permissions as below, that user/role can login into Docker via CLI and still only access those images that user/role is supposed to.
Example with scoped permissions:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"ecr:BatchGetImage",
"ecr:BatchCheckLayerAvailability",
"ecr:CompleteLayerUpload",
"ecr:GetDownloadUrlForLayer",
"ecr:InitiateLayerUpload",
"ecr:PutImage",
"ecr:UploadLayerPart"
],
"Resource": "arn:aws:ecr:${region}:${account}:repository/${repo-name}"
},
{
"Effect": "Allow",
"Action": "ecr:GetAuthorizationToken",
"Resource": "*"
}
]
}
From my observations, scoping ecr:GetAuthorizationToken to any ECR repositories will result in AccessDeniedException.