Bug 1876 (agent-context)

Summary: Requests to use keys held by the ssh-agent have no way of indicating their context
Product: Portable OpenSSH Reporter: Daniel Kahn Gillmor <dkg>
Component: ssh-agentAssignee: Assigned to nobody <unassigned-bugs>
Status: NEW ---    
Severity: enhancement CC: djm, pub
Priority: P2    
Version: 5.8p1   
Hardware: All   
OS: All   

Description Daniel Kahn Gillmor 2011-03-08 05:32:28 AEDT 
When the ssh-agent receives a request to use one of the keys it holds, it gets no context information from the requesting system about what the key operation is to be used for.

My own typical workflow (as a user who actively monitors and confirms the use of my keys by the ssh-agent) is to just correlate things by time.  e.g. "i just did action X, so i expect key Y to be used right around now, so i'll say OK".

If there was a way to communicate the context of the use to the agent, so that the agent could relay that to the user in whatever notification or confirmation it provides, it would seem like a Good Thing.

If there was a way to do that with some measures of cryptographic reliability (e.g. so that a malicious client couldn't say "please make this signature for X" when it was actually intending to be used for Y), it would be even better.  I'm not sure i understand how that could happen, though i'd be happy to consider proposals/suggestions.

I suspect this would require at least an extension to the ssh-agent protocol, but i'm not sure where or how that would be done.