[CRIU] Hardening the criu service daemon

[Pavel Emelyanov]

On 09/11/2015 04:20 PM, Florian Weimer wrote:
> On 09/01/2015 01:23 PM, Pavel Emelyanov wrote:
> 
>>> You'd still need something stronger than a PID to attach to the process
>>> (the requester process).
>>
>> A /proc/pid/something file can be such. Once open()-ed it will pin the struct pid,
>> so openat(that_fd, "path") will be able to access the original process safely.
> 
> It's still not clear to me how you can go from the incoming socket
> connection to the correct process in a race-free manner.

Smth like this from my perspective should work:

1. task connects to criu using unix socket
2. criu gets the peer's pid using SO_PEERCRED sockopt
3. criu freezes the task
4. criu checks task's fdtable to contain the connection socket

The latter check is still not there though :( but everything
is prepared for it.

-- Pavel