lkml.org 
[lkml]   [2011]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH 02/14] allow root in container to copy namespaces
    Serge Hallyn <serge@hallyn.com> writes:

    > From: Serge E. Hallyn <serge.hallyn@canonical.com>
    >
    > Othewise nested containers with user namespaces won't be possible.
    >
    > It's true that user namespaces are not yet fully isolated, but for
    > that same reason there are far worse things that root in a child
    > user ns can do. Spawning a child user ns is not in itself bad.
    >
    > This patch also allows setns for root in a container:
    > @Eric Biederman: are there gotchas in allowing setns from child
    > userns?

    Yes. We need to ensure that the target namespaces are namespaces
    that have been created in from user_namespace or from a child of this
    user_namespace.

    Aka we need to ensure that we have CAP_SYS_ADMIN for the new namespace.

    Eric

    > Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
    > Cc: Eric W. Biederman <ebiederm@xmission.com>
    > ---
    > kernel/fork.c | 4 ++--
    > kernel/nsproxy.c | 6 +++---
    > 2 files changed, 5 insertions(+), 5 deletions(-)
    >
    > diff --git a/kernel/fork.c b/kernel/fork.c
    > index 17bf7c8..22d0cf0 100644
    > --- a/kernel/fork.c
    > +++ b/kernel/fork.c
    > @@ -1473,8 +1473,8 @@ long do_fork(unsigned long clone_flags,
    > /* hopefully this check will go away when userns support is
    > * complete
    > */
    > - if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) ||
    > - !capable(CAP_SETGID))
    > + if (!nsown_capable(CAP_SYS_ADMIN) || !nsown_capable(CAP_SETUID) ||
    > + !nsown_capable(CAP_SETGID))
    > return -EPERM;
    > }
    >
    > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
    > index 9aeab4b..f50542d 100644
    > --- a/kernel/nsproxy.c
    > +++ b/kernel/nsproxy.c
    > @@ -134,7 +134,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
    > CLONE_NEWPID | CLONE_NEWNET)))
    > return 0;
    >
    > - if (!capable(CAP_SYS_ADMIN)) {
    > + if (!nsown_capable(CAP_SYS_ADMIN)) {
    > err = -EPERM;
    > goto out;
    > }
    > @@ -191,7 +191,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
    > CLONE_NEWNET)))
    > return 0;
    >
    > - if (!capable(CAP_SYS_ADMIN))
    > + if (!nsown_capable(CAP_SYS_ADMIN))
    > return -EPERM;
    >
    > *new_nsp = create_new_namespaces(unshare_flags, current,
    > @@ -241,7 +241,7 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype)
    > struct file *file;
    > int err;
    >
    > - if (!capable(CAP_SYS_ADMIN))
    > + if (!nsown_capable(CAP_SYS_ADMIN))
    > return -EPERM;
    >
    > file = proc_ns_fget(fd);


    \
     
     \ /
      Last update: 2011-07-28 01:17    [W:0.032 / U:1.512 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site