linux-stable.git/security/keys/keyctl.c, branch v3.5.2

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2012-06-01T01:47:30+00:00

Pull second pile of signal handling patches from Al Viro:
 "This one is just task_work_add() series + remaining prereqs for it.

  There probably will be another pull request from that tree this
  cycle - at least for helpers, to get them out of the way for per-arch
  fixes remaining in the tree."

Fix trivial conflict in kernel/irq/manage.c: the merge of Andrew's pile
had brought in commit 97fd75b7b8e0 ("kernel/irq/manage.c: use the
pr_foo() infrastructure to prefix printks") which changed one of the
pr_err() calls that this merge moves around.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  keys: kill task_struct->replacement_session_keyring
  keys: kill the dummy key_replace_session_keyring()
  keys: change keyctl_session_to_parent() to use task_work_add()
  genirq: reimplement exit_irq_thread() hook via task_work_add()
  task_work_add: generic process-context callbacks
  avr32: missed _TIF_NOTIFY_RESUME on one of do_notify_resume callers
  parisc: need to check NOTIFY_RESUME when exiting from syscall
  move key_repace_session_keyring() into tracehook_notify_resume()
  TIF_NOTIFY_RESUME is defined on all targets now

aio/vfs: cleanup of rw_copy_check_uvector() and compat_rw_copy_check_uvector()

2012-06-01T00:49:32+00:00

A cleanup of rw_copy_check_uvector and compat_rw_copy_check_uvector after
changes made to support CMA in an earlier patch.

Rather than having an additional check_access parameter to these
functions, the first paramater type is overloaded to allow the caller to
specify CHECK_IOVEC_ONLY which means check that the contents of the iovec
are valid, but do not check the memory that they point to.  This is used
by process_vm_readv/writev where we need to validate that a iovec passed
to the syscall is valid but do not want to check the memory that it points
to at this point because it refers to an address space in another process.

Signed-off-by: Chris Yeoh 
Reviewed-by: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

security/keys/keyctl.c: suppress memory allocation failure warning

2012-06-01T00:49:26+00:00

This allocation may be large.  The code is probing to see if it will
succeed and if not, it falls back to vmalloc().  We should suppress any
page-allocation failure messages when the fallback happens.

Reported-by: Dave Jones 
Acked-by: David Howells 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

keys: change keyctl_session_to_parent() to use task_work_add()

2012-05-24T02:11:23+00:00

Change keyctl_session_to_parent() to use task_work_add() and move
key_replace_session_keyring() logic into task_work->func().

Note that we do task_work_cancel() before task_work_add() to ensure that
only one work can be pending at any time.  This is important, we must not
allow user-space to abuse the parent's ->task_works list.

The callback, replace_session_keyring(), checks PF_EXITING.  I guess this
is not really needed but looks better.

As a side effect, this fixes the (unlikely) race.  The callers of
key_replace_session_keyring() and keyctl_session_to_parent() lack the
necessary barriers, the parent can miss the request.

Now we can remove task_struct->replacement_session_keyring and related
code.

Signed-off-by: Oleg Nesterov 
Acked-by: David Howells 
Cc: Thomas Gleixner 
Cc: Richard Kuo 
Cc: Linus Torvalds 
Cc: Alexander Gordeev 
Cc: Chris Zankel 
Cc: David Smith 
Cc: "Frank Ch. Eigler" 
Cc: Geert Uytterhoeven 
Cc: Larry Woodman 
Cc: Peter Zijlstra 
Cc: Tejun Heo 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

TIF_NOTIFY_RESUME is defined on all targets now

2012-05-24T02:09:19+00:00

Signed-off-by: Al Viro

KEYS: Add invalidation support

2012-05-11T09:56:56+00:00

Add support for invalidating a key - which renders it immediately invisible to
further searches and causes the garbage collector to immediately wake up,
remove it from keyrings and then destroy it when it's no longer referenced.

It's better not to do this with keyctl_revoke() as that marks the key to start
returning -EKEYREVOKED to searches when what is actually desired is to have the
key refetched.

To invalidate a key the caller must be granted SEARCH permission by the key.
This may be too strict.  It may be better to also permit invalidation if the
caller has any of READ, WRITE or SETATTR permission.

The primary use for this is to evict keys that are cached in special keyrings,
such as the DNS resolver or an ID mapper.

Signed-off-by: David Howells

Merge tag 'nfs-for-3.4-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2012-03-23T15:53:47+00:00

Pull NFS client updates for Linux 3.4 from Trond Myklebust:
 "New features include:
   - Add NFS client support for containers.

     This should enable most of the necessary functionality, including
     lockd support, and support for rpc.statd, NFSv4 idmapper and
     RPCSEC_GSS upcalls into the correct network namespace from which
     the mount system call was issued.

   - NFSv4 idmapper scalability improvements

     Base the idmapper cache on the keyring interface to allow
     concurrent access to idmapper entries.  Start the process of
     migrating users from the single-threaded daemon-based approach to
     the multi-threaded request-key based approach.

   - NFSv4.1 implementation id.

     Allows the NFSv4.1 client and server to mutually identify each
     other for logging and debugging purposes.

   - Support the 'vers=4.1' mount option for mounting NFSv4.1 instead of
     having to use the more counterintuitive 'vers=4,minorversion=1'.

   - SUNRPC tracepoints.

     Start the process of adding tracepoints in order to improve
     debugging of the RPC layer.

   - pNFS object layout support for autologin.

  Important bugfixes include:

   - Fix a bug in rpc_wake_up/rpc_wake_up_status that caused them to
     fail to wake up all tasks when applied to priority waitqueues.

   - Ensure that we handle read delegations correctly, when we try to
     truncate a file.

   - A number of fixes for NFSv4 state manager loops (mostly to do with
     delegation recovery)."

* tag 'nfs-for-3.4-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (224 commits)
  NFS: fix sb->s_id in nfs debug prints
  xprtrdma: Remove assumption that each segment is <= PAGE_SIZE
  xprtrdma: The transport should not bug-check when a dup reply is received
  pnfs-obj: autologin: Add support for protocol autologin
  NFS: Remove nfs4_setup_sequence from generic rename code
  NFS: Remove nfs4_setup_sequence from generic unlink code
  NFS: Remove nfs4_setup_sequence from generic read code
  NFS: Remove nfs4_setup_sequence from generic write code
  NFS: Fix more NFS debug related build warnings
  SUNRPC/LOCKD: Fix build warnings when CONFIG_SUNRPC_DEBUG is undefined
  nfs: non void functions must return a value
  SUNRPC: Kill compiler warning when RPC_DEBUG is unset
  SUNRPC/NFS: Add Kbuild dependencies for NFS_DEBUG/RPC_DEBUG
  NFS: Use cond_resched_lock() to reduce latencies in the commit scans
  NFSv4: It is not safe to dereference lsp->ls_state in release_lockowner
  NFS: ncommit count is being double decremented
  SUNRPC: We must not use list_for_each_entry_safe() in rpc_wake_up()
  Try using machine credentials for RENEW calls
  NFSv4.1: Fix a few issues in filelayout_commit_pagelist
  NFSv4.1: Clean ups and bugfixes for the pNFS read/writeback/commit code
  ...

Created a function for setting timeouts on keys

2012-03-01T21:50:31+00:00

The keyctl_set_timeout function isn't exported to other parts of the
kernel, but I want to use it for the NFS idmapper.  I already have the
key, but I wanted a generic way to set the timeout.

Signed-off-by: Bryan Schumaker 
Acked-by: David Howells 
Signed-off-by: Trond Myklebust

KEYS: Allow special keyrings to be cleared

2012-01-19T03:38:51+00:00

The kernel contains some special internal keyrings, for instance the DNS
resolver keyring :

2a93faf1 I-----     1 perm 1f030000     0     0 keyring   .dns_resolver: empty

It would occasionally be useful to allow the contents of such keyrings to be
flushed by root (cache invalidation).

Allow a flag to be set on a keyring to mark that someone possessing the
sysadmin capability can clear the keyring, even without normal write access to
the keyring.

Set this flag on the special keyrings created by the DNS resolver, the NFS
identity mapper and the CIFS identity mapper.

Signed-off-by: David Howells 
Acked-by: Jeff Layton 
Acked-by: Steve Dickson 
Signed-off-by: James Morris

Cross Memory Attach

2011-11-01T00:30:44+00:00

The basic idea behind cross memory attach is to allow MPI programs doing
intra-node communication to do a single copy of the message rather than a
double copy of the message via shared memory.

The following patch attempts to achieve this by allowing a destination
process, given an address and size from a source process, to copy memory
directly from the source process into its own address space via a system
call.  There is also a symmetrical ability to copy from the current
process's address space into a destination process's address space.

- Use of /proc/pid/mem has been considered, but there are issues with
  using it:
  - Does not allow for specifying iovecs for both src and dest, assuming
    preadv or pwritev was implemented either the area read from or
  written to would need to be contiguous.
  - Currently mem_read allows only processes who are currently
  ptrace'ing the target and are still able to ptrace the target to read
  from the target. This check could possibly be moved to the open call,
  but its not clear exactly what race this restriction is stopping
  (reason  appears to have been lost)
  - Having to send the fd of /proc/self/mem via SCM_RIGHTS on unix
  domain socket is a bit ugly from a userspace point of view,
  especially when you may have hundreds if not (eventually) thousands
  of processes  that all need to do this with each other
  - Doesn't allow for some future use of the interface we would like to
  consider adding in the future (see below)
  - Interestingly reading from /proc/pid/mem currently actually
  involves two copies! (But this could be fixed pretty easily)

As mentioned previously use of vmsplice instead was considered, but has
problems.  Since you need the reader and writer working co-operatively if
the pipe is not drained then you block.  Which requires some wrapping to
do non blocking on the send side or polling on the receive.  In all to all
communication it requires ordering otherwise you can deadlock.  And in the
example of many MPI tasks writing to one MPI task vmsplice serialises the
copying.

There are some cases of MPI collectives where even a single copy interface
does not get us the performance gain we could.  For example in an
MPI_Reduce rather than copy the data from the source we would like to
instead use it directly in a mathops (say the reduce is doing a sum) as
this would save us doing a copy.  We don't need to keep a copy of the data
from the source.  I haven't implemented this, but I think this interface
could in the future do all this through the use of the flags - eg could
specify the math operation and type and the kernel rather than just
copying the data would apply the specified operation between the source
and destination and store it in the destination.

Although we don't have a "second user" of the interface (though I've had
some nibbles from people who may be interested in using it for intra
process messaging which is not MPI).  This interface is something which
hardware vendors are already doing for their custom drivers to implement
fast local communication.  And so in addition to this being useful for
OpenMPI it would mean the driver maintainers don't have to fix things up
when the mm changes.

There was some discussion about how much faster a true zero copy would
go. Here's a link back to the email with some testing I did on that:

http://marc.info/?l=linux-mm&m=130105930902915&w=2

There is a basic man page for the proposed interface here:

http://ozlabs.org/~cyeoh/cma/process_vm_readv.txt

This has been implemented for x86 and powerpc, other architecture should
mainly (I think) just need to add syscall numbers for the process_vm_readv
and process_vm_writev. There are 32 bit compatibility versions for
64-bit kernels.

For arch maintainers there are some simple tests to be able to quickly
verify that the syscalls are working correctly here:

http://ozlabs.org/~cyeoh/cma/cma-test-20110718.tgz

Signed-off-by: Chris Yeoh 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: David Howells 
Cc: James Morris 
Cc: 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds