[Gluster-devel] REST API authentication: JWT - Shared Token vs Shared Secret

[Aravinda]

regards
Aravinda

On 03/03/2016 05:58 PM, Kaushal M wrote:
> On Thu, Mar 3, 2016 at 2:39 PM, Aravinda <avishwan at redhat.com> wrote:
>> Thanks.
>>
>> We can use Shared secret if https requirement can be completely
>> avoided. I am not sure how to use same SSL certificates in all the
>> nodes of the Cluster.(REST API server patch set 2 was written based on
>> shared secret method based on custom HMAC signing
>> http://review.gluster.org/#/c/13214/2/in_progress/management_rest_api.md)
>>
>> Listing the steps involved in each side with both the
>> approaches. (Skipping Register steps since it is common to both)
>>
>> Shared Token:
>> -------------
>> Client side:
>> 1. Add saved token Authorization header and initiate a REST call.
>> 2. If UnAuthorized, call /token and get access_token again and repeat
>>     the step 1
>>
>> Server side:
>> 1. Verify JWT using the Server's secret.
> You forgot the part where server generates the token. :)
Oh Yes. I missed that step :)
>
>>
>> Shared Secret:
>> --------------
>> Client side:
>> 1. Hash the Method + URL + Params and include in qsh claim of JWT
>> 2. Using shared secret, create JWT.
>> 3. Add previously generated JWT in Authorization header and initiate
>>     REST call
>>
>> Server side:
>> 1. Recalculate the hash using same details (Method + URL + Params) and
>>     verify with received qsh
>> 2. Do not trust any claims, validate against the values stored in
>>     Server(role/group/capabilities)
>> 3. Verify JWT using the shared secret
>>
> Anyways, I'm still not sure which of the two approaches I like better.
> My google research on this topic (ReST api authentication) led to many
> results which followed a token approach.
> This causes me to lean slightly towards shared tokens.
Yeah, Shared token is widely used method. But https is mandatory to 
avoid URL tampering. But using SSL certs in multi node setup is 
tricky.(Using same cert files across all nodes)

Shared secret approach it is difficult to test using curl or 
Postman(https://www.getpostman.com/)

>
> Since, I can't decide, I plan to write down workflows involved for
> both and try to compare them that way.
> It would probably help arrive at a decision. I'll try to share this
> ASAP (probably this weekend).
Thanks.
>
>> regards
>> Aravinda
>>
>>
>> On 03/03/2016 11:49 AM, Luis Pabon wrote:
>>> Hi Aravinda,
>>>     Very good summary.  I would like to rephrase a few parts.
>>>
>>> On the shared token approach, the disadvantage is that the server will be
>>> more complicated (not *really* complicated, just more than the shared
>>> token), because it would need a login mechanism.  Server would have to both
>>> authenticate and authorize the user.  Once this has occurred a token with an
>>> expiration date can be handed back to the caller.
>>>
>>> On the shared secret approach, I do not consider the client creating a JWT
>>> a disadvantage (unless you are doing it in C), it is pretty trivial for
>>> programs written in Python, Go, Javascript etc to create a JWT on each call.
>>>
>>> - Luis
>>>
>>> ----- Original Message -----
>>> From: "Aravinda" <avishwan at redhat.com>
>>> To: "Gluster Devel" <gluster-devel at gluster.org>
>>> Cc: "Kaushal Madappa" <kmadappa at redhat.com>, "Atin Mukherjee"
>>> <amukherj at redhat.com>, "Luis Pabon" <lpabon at redhat.com>,
>>> kmayilsa at redhat.com, "Prashanth Pai" <ppai at redhat.com>
>>> Sent: Wednesday, March 2, 2016 1:53:00 AM
>>> Subject: REST API authentication: JWT - Shared Token vs Shared Secret
>>>
>>> Hi,
>>>
>>> For Gluster REST project we are planning to use JSON Web Token for
>>> authentication. There are two approaches to use JWT, please help us to
>>> evaluate between these two options.
>>>
>>> http://jwt.io/
>>>
>>> For both approach, user/app will register with Username and Secret.
>>>
>>> Shared Token Approach:(Default as per JWT website
>>> http://jwt.io/introduction/)
>>>
>>> ------------------------------------------------------------------------------
>>> Server will generate JWT with pre-configured expiry once user login to
>>> server by providing Username and Secret. Secret is encrypted and
>>> stored in Server. Clients should include that JWT in all requests.
>>>
>>> Advantageous:
>>> 1. Clients need not worry anything about JWT signing.
>>> 2. Single secret at server side can be used for all token verification.
>>> 3. This is a stateless authentication mechanism as the user state is
>>>       never saved in the server memory(http://jwt.io/introduction/)
>>> 4. Secret is encrypted and stored in Server.
>>>
>>> Disadvantageous:
>>> 1. URL Tampering can be protected only by using HTTPS.
>>>
>>> Shared Secret Approach:
>>> -----------------------
>>> Secret will not be encrypted in Server side because secret is
>>> required for JWT signing and verification. Clients will sign every
>>> request using Secret and send that signature along with the
>>> request. Server will sign again using the same secret to check the
>>> signature match.
>>>
>>> Advantageous:
>>> 1. Protection against URL Tampering without HTTPS.
>>> 2. Different expiry time management based on issued time
>>>
>>> Disadvantageous:
>>> 1. Clients should be aware of JWT and Signing
>>> 2. Shared secrets will be stored as plain text format in server.
>>> 3. Every request should lookup for shared secret per user.
>>>
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