memcpy() from userland pointer is a Bad Thing(tm)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix imbalanced calls for mutex lock/unlock on ecryptfs_daemon_hash_mux
Revealed by Ingo Molnar: http://lkml.org/lkml/2008/5/7/260Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus 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: NMichael Halcrow <mhalcrow@us.ibm.com>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus 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: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus 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: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>