A crop of new capabilities

Posted Jun 9, 2020 0:15 UTC (Tue) by nickodell (subscriber, #125165)
Parent article: A crop of new capabilities

>Setting the ID of a new process is possible with clone3(), but this feature is not available to unprivileged processes. The ability to create processes with a chosen ID would make a number of attacks easier, so ID setting is restricted to processes with, of course, CAP_SYS_ADMIN. Administrators tend to balk at handing out that capability, so CRIU users have been resorting to a number of workarounds; Reber listed a few that vary from the reasonable to the appalling:
So what are you supposed to do if some other process starts using that PID?

I don't get what the issue is with using a PID namespace. It seems like it fixes both the permissions issue and the collision issue.

A crop of new capabilities

Posted Jun 9, 2020 0:24 UTC (Tue) by Cyberax (✭ supporter ✭, #52523) [Link]

Each PID namespace starts PIDs from 1. So this shouldn't be an issue.

A crop of new capabilities

Posted Jun 10, 2020 4:05 UTC (Wed) by NYKevin (subscriber, #129325) [Link]

Obviously, you're supposed to send them a SIGSEGV with kill(2), and hope whoever's responsible for that binary never figures out their impossible-to-reproduce segfault bug.

I mean, that's almost as sensible as some of the other suggestions in the article, right?