aws policy variable ${aws:username} returning error not authorized - amazon-web-services

Question

I have followed the docs at aws http://docs.aws.amazon.com/IAM/latest/UserGuide/PolicyVariables.html
and the question at Can an aws IAM policy dynamically refer to the logged in username?
to create a policy for a user to list his own credentials under web console/users so he can generate his own keys.
user/Alpha
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Action":["iam:*"],
"Resource":["arn:aws:iam::{myacctnumber}:user/${aws:username}"]
}
]
}
when I attach the the policy to user/Alpha, then open a new browser and log in as user Alpha > console > users, I get the error message
We encountered the following errors while processing your request
X User: arn:aws:iam::{myacctnumber}:user/Alpha is not authorized to perform: iam ListUsers on resource: arn:aws:iam::{myacctnumber}:user/
note the user/ is not displaying the friendly name as would be expected from ${aws:username}.
I have also tried changing the policy to
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Action":["iam:*"],
"Resource":["arn:aws:iam::{myacctnumber}:user/Alpha"]
}
]
}
but the same error displays.
If I make one further change to the resource and make it a wildcard,
"Resource":["arn:aws:iam::{myacctnumber}:user/*"]
the full user list is displayed to to the user Alpha
Do I need extra permissions to allow a user to see only themselves?
thx
Art

Answer 1

The console, when displaying a list of users, uses the iam:ListUsers API call. This call cannot be restricted by resource.
Therefore, the console will function correctly if you provide a policies that permits the ListUsers call, eg:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"iam:ListUsers"
],
"Resource": [
"*"
]
}
]
}
The only other way for the user to update their own settings would be via the AWS Command-Line Interface (CLI) or an API call, since they can avoid the need to call ListUsers.