On 06/27/2013 10:45 PM, Simo Sorce wrote:
On Thu, 2013-06-27 at 17:49 -0700, Clint Byrum wrote:
On 2013-06-27 16:28, Jamie Lennox wrote:
On Fri, 2013-06-28 at 07:01 +1200, Robert Collins wrote:
On 27 June 2013 04:55, Adam Young <ayo...@redhat.com> wrote:
Right now Keystone provides so called bearer tokens: This means that
whoever
has a token can do whatever the token entitles him to do. If I
manage to get somebody's token I can do whatever this person is able
to do.
To fix it, the other services that use tokens to:
1. Authenticate the identity
2. Match the name in the token to the identity that authenticated
the
connection.
I am confused: HTTP is a message orientated protocol, connection
based
authentication is a terrible antipattern. Do you really mean
'connection' here?
More the HTTPs handshake i guess, the point is to have for example a
client certificate or kerberos identity that is used to connect to the
individual servers.
When a token is generated from keystone we put into the token a
reference to the kerberos or cert that was used to generate the token,
then when this token is used on a server the auth_token middleware
ensures that the same kerberos principal or certificate is used to
make
that connection as made the original. That means even if you get the
token unless you have the cert/kerberos id you can't use it.
The full blueprint is:
https://blueprints.launchpad.net/keystone/+spec/authentication-tied-to-token
So you need the cert/kerberos ticket to both create and use the token.
So this means you are really trying to solve the problem of us
transmitting whole tokens for each request, making them open to
interception during transmission or theft from backing storage.
If the names match then you can be sure that the user that connected
to the
service and presented a token is the same user that acquired the
token from
keystone in the first place.
That would prevent the use case of 'create a token and hand it off'
which AIUI Heat depends on/will depend on.
Yes it would, but this is where heat would need to make use of the
trusts mechanism that was released with Grizzly, something that i
understand is planned anyway.
Indeed it is. But right now, the most excellent "make an EC2 keypair
and sign stuff with it" scheme is working out pretty well. That scheme
at least eliminates the transmission vulnerability.
Using a private key to sign requests is certainly an option that is
certainly to be considered.
It was considered. However, when you get down to the management of
those keys, and how to sign the messages, it is no less complex than
dealing with X509 Certificates, and X509 is already implemented.
X509 has a format for authentication information in a separate signed
document from the initial certificate itself, but deployment of it is
not very wide spread. From our perspective, it makes more sense to
continue to use Keystone tokens for authorization information, and link
it to a secure Authentication source. We are giving people the choice
between X509 and Kerberos out the door, although any other secure
authentication source would be viable as well.
In order to do that thought it would be easier if all clients would use
the same http library and keystone client so that signing can also be
done mostly transparently to the clients by hooking into the http
library and signing the request before it is sent.
Simo.
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