linux-toradex.git/include/linux/utsname.h, branch v4.11-rc3

utsns: Add a limit on the number of uts namespaces

2016-08-08T19:42:02+00:00

Acked-by: Kees Cook 
Signed-off-by: "Eric W. Biederman"

common object embedded into various struct ....ns

2014-12-04T19:31:00+00:00

for now - just move corresponding ->proc_inum instances over there

Acked-by: "Eric W. Biederman" 
Signed-off-by: Al Viro

proc: Usable inode numbers for the namespace file descriptors.

2012-11-20T12:19:49+00:00

Assign a unique proc inode to each namespace, and use that
inode number to ensure we only allocate at most one proc
inode for every namespace in proc.

A single proc inode per namespace allows userspace to test
to see if two processes are in the same namespace.

This has been a long requested feature and only blocked because
a naive implementation would put the id in a global space and
would ultimately require having a namespace for the names of
namespaces, making migration and certain virtualization tricks
impossible.

We still don't have per superblock inode numbers for proc, which
appears necessary for application unaware checkpoint/restart and
migrations (if the application is using namespace file descriptors)
but that is now allowd by the design if it becomes important.

I have preallocated the ipc and uts initial proc inode numbers so
their structures can be statically initialized.

Signed-off-by: Eric W. Biederman

userns: Make create_new_namespaces take a user_ns parameter

2012-11-20T12:17:43+00:00

Modify create_new_namespaces to explicitly take a user namespace
parameter, instead of implicitly through the task_struct.

This allows an implementation of unshare(CLONE_NEWUSER) where
the new user namespace is not stored onto the current task_struct
until after all of the namespaces are created.

Acked-by: Serge Hallyn 
Signed-off-by: "Eric W. Biederman"

UAPI: (Scripted) Disintegrate include/linux

2012-10-13T09:46:48+00:00

Signed-off-by: David Howells 
Acked-by: Arnd Bergmann 
Acked-by: Thomas Gleixner 
Acked-by: Michael Kerrisk 
Acked-by: Paul E. McKenney 
Acked-by: Dave Jones

sysctl: add support for poll()

2011-11-02T23:07:02+00:00

Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries.  This adds a infrastructure to
allow files in sysctl fs to be pollable and implements it for hostname and
domainname.

[akpm@linux-foundation.org: s/declare/define/ for definitions]
Signed-off-by: Lucas De Marchi 
Cc: Greg KH 
Cc: Kay Sievers 
Cc: Al Viro 
Cc: "Eric W. Biederman" 
Cc: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

userns: allow sethostname in a container

2011-03-24T02:47:03+00:00

Changelog:
	Feb 23: let clone_uts_ns() handle setting uts->user_ns
		To do so we need to pass in the task_struct who'll
		get the utsname, so we can get its user_ns.
	Feb 23: As per Oleg's coment, just pass in tsk, instead of two
		of its members.

Signed-off-by: Serge E. Hallyn 
Acked-by: "Eric W. Biederman" 
Acked-by: Daniel Lezcano 
Acked-by: David Howells 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

userns: add a user_namespace as creator/owner of uts_namespace

2011-03-24T02:46:59+00:00

The expected course of development for user namespaces targeted
capabilities is laid out at https://wiki.ubuntu.com/UserNamespace.

Goals:

- Make it safe for an unprivileged user to unshare namespaces.  They
  will be privileged with respect to the new namespace, but this should
  only include resources which the unprivileged user already owns.

- Provide separate limits and accounting for userids in different
  namespaces.

Status:

  Currently (as of 2.6.38) you can clone with the CLONE_NEWUSER flag to
  get a new user namespace if you have the CAP_SYS_ADMIN, CAP_SETUID, and
  CAP_SETGID capabilities.  What this gets you is a whole new set of
  userids, meaning that user 500 will have a different 'struct user' in
  your namespace than in other namespaces.  So any accounting information
  stored in struct user will be unique to your namespace.

  However, throughout the kernel there are checks which

  - simply check for a capability.  Since root in a child namespace
    has all capabilities, this means that a child namespace is not
    constrained.

  - simply compare uid1 == uid2.  Since these are the integer uids,
    uid 500 in namespace 1 will be said to be equal to uid 500 in
    namespace 2.

  As a result, the lxc implementation at lxc.sf.net does not use user
  namespaces.  This is actually helpful because it leaves us free to
  develop user namespaces in such a way that, for some time, user
  namespaces may be unuseful.

Bugs aside, this patchset is supposed to not at all affect systems which
are not actively using user namespaces, and only restrict what tasks in
child user namespace can do.  They begin to limit privilege to a user
namespace, so that root in a container cannot kill or ptrace tasks in the
parent user namespace, and can only get world access rights to files.
Since all files currently belong to the initila user namespace, that means
that child user namespaces can only get world access rights to *all*
files.  While this temporarily makes user namespaces bad for system
containers, it starts to get useful for some sandboxing.

I've run the 'runltplite.sh' with and without this patchset and found no
difference.

This patch:

copy_process() handles CLONE_NEWUSER before the rest of the namespaces.
So in the case of clone(CLONE_NEWUSER|CLONE_NEWUTS) the new uts namespace
will have the new user namespace as its owner.  That is what we want,
since we want root in that new userns to be able to have privilege over
it.

Changelog:
	Feb 15: don't set uts_ns->user_ns if we didn't create
		a new uts_ns.
	Feb 23: Move extern init_user_ns declaration from
		init/version.c to utsname.h.

Signed-off-by: Serge E. Hallyn 
Acked-by: "Eric W. Biederman" 
Acked-by: Daniel Lezcano 
Acked-by: David Howells 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

headers: utsname.h redux

2009-09-24T01:13:10+00:00

* remove asm/atomic.h inclusion from linux/utsname.h --
   not needed after kref conversion
 * remove linux/utsname.h inclusion from files which do not need it

NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however
due to some personality stuff it _is_ needed -- cowardly leave ELF-related
headers and files alone.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Linus Torvalds

utsname.h: make new_utsname fields use the proper length constant

2009-06-17T02:47:47+00:00

The members of the new_utsname structure are defined with magic numbers
that *should* correspond to the constant __NEW_UTS_LEN+1.  Everywhere
else, code assumes this and uses the constant, so this patch makes the
structure match.

Originally suggested by Serge here:

https://lists.linux-foundation.org/pipermail/containers/2009-March/016258.html

Signed-off-by: Dan Smith 
Acked-by: Serge Hallyn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds