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Date: Wed, 2 Apr 2014 19:32:49 +0200 From: "Serge E. Hallyn" <serge@...lyn.com> To: Serge Hallyn <serge.hallyn@...ntu.com> Cc: "Eric W. Biederman" <ebiederm@...ssion.com>, Sean Pajot <sean.pajot@...culink.com>, lxc-devel@...ts.linuxcontainers.org, linux-kernel@...r.kernel.org Subject: Re: [lxc-devel] Kernel bug? Setuid apps and user namespaces (Sorry - the lxc-devel list has moved, so replying to all with the correct list address; please reply to this rather than my previous email) Quoting Serge Hallyn (serge.hallyn@...ntu.com): > Hi Eric, > > (sorry, I don't seem to have the email I actually wanted to reply > to in my mbox, but it is > https://lists.linuxcontainers.org/pipermail/lxc-devel/2013-October/005857.html) > > You'd said, > > Someone needs to read and think through all of the corner cases and see > > if we can ever have a time when task_dumpable is false but root in the > > container would not or should not be able to see everything. > > > > In particular I am worried about the case of a setuid app calling setns, > > and entering a lesser privileged user namespace. In my foggy mind that > > might be a security problem. And there might be other similar crazy > > cases. > > Can we make use of current->mm->exe_file->f_cred->user_ns? > > So either always use > make_kgid(current->mm->exe_file->f_cred->user_ns, 0) > instead of make_kuid(cred->user_ns, 0), or check that > (current->mm->exe_file->f_cred->user_ns == cred->user_ns) > and, if not, assume that the caller has done a setns? > > -serge > -- > 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/ -- 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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