On Thu, Jul 21, 2016, at 12:39 PM, Eric W. Biederman wrote: > > This patchset addresses two use cases: > - Implement a sane upper bound on the number of namespaces. > - Provide a way for sandboxes to limit the attack surface from > namespaces. Perhaps this is obvious, but since you didn't quite explicitly state it; do you see this as obsoleting the existing downstream patches mentioned in: https://lwn.net/Articles/673597/ It seems conceptually similar to Kees' original approach, right? The high level makes sense to me...most interesting is per-userns sysctls. I'll note most current container managers mount /proc/sys read-only, and Docker specifically drops CAP_SYS_RESOURCE by default, so they'd likely need to learn how to undo that if one wanted to support recursive container usage. We'd probably need to evaluate the safety of having /proc/sys writable generally. (Also it's rather common to filter out CLONE_NEWUSER via seccomp, but that's easy to undo) But that's the flip side - if we're aiming primarily for an upstreamable way to *limit* namespace usage, it seems sane to me. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html