On 04/02/2014 10:32 AM, Serge E. Hallyn wrote: > (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.hal...@ubuntu.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?
Do you have a summary of the issue? I'm a little lost here. I suspect that what we really need is to revoke a bunch of proc files every time a task does anything involving setuid (or, more generally, any of the LSM_UNSAFE_PTRACE things). --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/