The user_ns is moved from nsproxy to user_struct, so that a struct
cred by itself is sufficient to determine access (which it otherwise
would not be). Corresponding ecryptfs fixes (by David Howells) are
here as well.
Fix refcounting. The following rules now apply:
1. The task pins the user struct.
2. The user struct pins its user namespace.
3. The user namespace pins the struct user which created it.
User namespaces are cloned during copy_creds(). Unsharing a new user_ns
is no longer possible. (We could re-add that, but it'll cause code
duplication and doesn't seem useful if PAM doesn't need to clone user
namespaces).
When a user namespace is created, its first user (uid 0) gets empty
keyrings and a clean group_info.
This incorporates a previous patch by David Howells. Here
is his original patch description:
>I suggest adding the attached incremental patch. It makes the following
>changes:
>
> (1) Provides a current_user_ns() macro to wrap accesses to current's user
> namespace.
>
> (2) Fixes eCryptFS.
>
> (3) Renames create_new_userns() to create_user_ns() to be more consistent
> with the other associated functions and because the 'new' in the name is
> superfluous.
>
> (4) Moves the argument and permission checks made for CLONE_NEWUSER to the
> beginning of do_fork() so that they're done prior to making any attempts
> at allocation.
>
> (5) Calls create_user_ns() after prepare_creds(), and gives it the new creds
> to fill in rather than have it return the new root user. I don't imagine
> the new root user being used for anything other than filling in a cred
> struct.
>
> This also permits me to get rid of a get_uid() and a free_uid(), as the
> reference the creds were holding on the old user_struct can just be
> transferred to the new namespace's creator pointer.
>
> (6) Makes create_user_ns() reset the UIDs and GIDs of the creds under
> preparation rather than doing it in copy_creds().
>
>David
>Signed-off-by: David Howells <dhowells@redhat.com>
Changelog:
Oct 20: integrate dhowells comments
1. leave thread_keyring alone
2. use current_user_ns() in set_user()
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.
Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Mike Halcrow <mhalcrow@us.ibm.com>
Cc: Phillip Hellewell <phillip@hellewell.homeip.net>
Cc: ecryptfs-devel@lists.sourceforge.net
Signed-off-by: James Morris <jmorris@namei.org>
The userspace eCryptfs daemon sends HELO and QUIT messages to the kernel
for per-user daemon (un)registration. These messages are required when
netlink is used as the transport, but (un)registration is handled by
opening and closing the device file when miscdev is the transport. These
messages should be discarded in the miscdev transport so that a daemon
isn't registered twice.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The misc_mtx should provide all the protection required to keep the daemon
hash table sane during miscdev registration. Since this mutex is causing
gratuitous lockdep warnings, this patch removes it.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Reported-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memcpy() from userland pointer is a Bad Thing(tm)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make eCryptfs key module subsystem respect namespaces.
Since I will be removing the netlink interface in a future patch, I just made
changes to the netlink.c code so that it will not break the build. With my
recent patches, the kernel module currently defaults to the device handle
interface rather than the netlink interface.
[akpm@linux-foundation.org: export free_user_ns()]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Update the versioning information. Make the message types generic. Add an
outgoing message queue to the daemon struct. Make the functions to parse
and write the packet lengths available to the rest of the module. Add
functions to create and destroy the daemon structs. Clean up some of the
comments and make the code a little more consistent with itself.
[akpm@linux-foundation.org: printk fixes]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A regular device file was my real preference from the get-go, but I went with
netlink at the time because I thought it would be less complex for managing
send queues (i.e., just do a unicast and move on). It turns out that we do
not really get that much complexity reduction with netlink, and netlink is
more heavyweight than a device handle.
In addition, the netlink interface to eCryptfs has been broken since 2.6.24.
I am assuming this is a bug in how eCryptfs uses netlink, since the other
in-kernel users of netlink do not seem to be having any problems. I have had
one report of a user successfully using eCryptfs with netlink on 2.6.24, but
for my own systems, when starting the userspace daemon, the initial helo
message sent to the eCryptfs kernel module results in an oops right off the
bat. I spent some time looking at it, but I have not yet found the cause.
The netlink interface breaking gave me the motivation to just finish my patch
to migrate to a regular device handle. If I cannot find out soon why the
netlink interface in eCryptfs broke, I am likely to just send a patch to
disable it in 2.6.24 and 2.6.25. I would like the device handle to be the
preferred means of communicating with the userspace daemon from 2.6.26 on
forward.
This patch:
Functions to facilitate reading and writing to the eCryptfs miscellaneous
device handle. This will replace the netlink interface as the preferred
mechanism for communicating with the userspace eCryptfs daemon.
Each user has his own daemon, which registers itself by opening the eCryptfs
device handle. Only one daemon per euid may be registered at any given time.
The eCryptfs module sends a message to a daemon by adding its message to the
daemon's outgoing message queue. The daemon reads the device handle to get
the oldest message off the queue.
Incoming messages from the userspace daemon are immediately handled. If the
message is a response, then the corresponding process that is blocked waiting
for the response is awakened.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Serge Hallyn