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Date: Thu, 25 Apr 2013 09:48:00 +0200 From: richard -rw- weinberger <richard.weinberger@...il.com> To: Michael Kerrisk-manpages <mtk.manpages@...il.com> Cc: "Eric W. Biederman" <ebiederm@...ssion.com>, Rob Landley <rob@...dley.net>, linux-man <linux-man@...r.kernel.org>, Linux Containers <containers@...ts.linux-foundation.org>, lkml <linux-kernel@...r.kernel.org>, Vasily Kulikov <segoon@...nwall.com>, Serge Hallyn <serge.hallyn@...ntu.com>, luto@...capital.net Subject: Re: For review (v2): user_namespaces(7) man page On Wed, Mar 27, 2013 at 10:26 PM, Michael Kerrisk (man-pages) <mtk.manpages@...il.com> wrote: > Inside the user namespace, the shell has user and group ID 0, > and a full set of permitted and effective capabilities: > > bash$ cat /proc/$$/status | egrep '^[UG]id' > Uid: 0 0 0 0 > Gid: 0 0 0 0 > bash$ cat /proc/$$/status | egrep '^Cap(Prm|Inh|Eff)' > CapInh: 0000000000000000 > CapPrm: 0000001fffffffff > CapEff: 0000001fffffffff I've tried your demo program, but inside the new ns I'm automatically nobody. As Eric said, setuid(0)/setgid(0) are missing. Eric, maybe you can help me. How can I drop capabilities within a user namespace? In childFunc() I did add prctl(PR_CAPBSET_DROP, CAP_NET_ADMIN) but it always returns ENOPERM. What that? I thought I get a completely fresh set of cap which I can modify. I don't want that uid 0 inside the container has all caps. And why does /proc/*/loginuid always contain 4294967295 in a new user namespace? Writing to it also fails. (Noticed that because pam_loginuid.so does not work). Final question, is it by design that uid 0 within a namespace in not allowed to write to /proc/*/oom_score_adj? Thanks, //richard P.s: I've used 3.9-rc8 for my tests... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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