[NETLINK]: cb_lock does not needs ref count on sk

Here is a little optimisation for the cb_lock used by netlink_dump.
While fixing that race earlier, I noticed that the reference count
held by cb_lock is completely useless.  The reason is that in order
to obtain the protection of the reference count, you have to take
the cb_lock.  But the only way to take the cb_lock is through
dereferencing the socket.

That is, you must already possess a reference count on the socket
before you can take advantage of the reference count held by cb_lock.
As a corollary, we can remve the reference count held by the cb_lock.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
[NETLINK]: Synchronous message processing.

Let's recap the problem.  The current asynchronous netlink kernel
message processing is vulnerable to these attacks:

1) Hit and run: Attacker sends one or more messages and then exits
before they're processed.  This may confuse/disable the next netlink
user that gets the netlink address of the attacker since it may
receive the responses to the attacker's messages.

Proposed solutions:

a) Synchronous processing.
b) Stream mode socket.
c) Restrict/prohibit binding.

2) Starvation: Because various netlink rcv functions were written
to not return until all messages have been processed on a socket,
it is possible for these functions to execute for an arbitrarily
long period of time.  If this is successfully exploited it could
also be used to hold rtnl forever.

Proposed solutions:

a) Synchronous processing.
b) Stream mode socket.

Firstly let's cross off solution c).  It only solves the first
problem and it has user-visible impacts.  In particular, it'll
break user space applications that expect to bind or communicate
with specific netlink addresses (pid's).

So we're left with a choice of synchronous processing versus
SOCK_STREAM for netlink.

For the moment I'm sticking with the synchronous approach as
suggested by Alexey since it's simpler and I'd rather spend
my time working on other things.

However, it does have a number of deficiencies compared to the
stream mode solution:

1) User-space to user-space netlink communication is still vulnerable.

2) Inefficient use of resources.  This is especially true for rtnetlink
since the lock is shared with other users such as networking drivers.
The latter could hold the rtnl while communicating with hardware which
causes the rtnetlink user to wait when it could be doing other things.

3) It is still possible to DoS all netlink users by flooding the kernel
netlink receive queue.  The attacker simply fills the receive socket
with a single netlink message that fills up the entire queue.  The
attacker then continues to call sendmsg with the same message in a loop.

Point 3) can be countered by retransmissions in user-space code, however
it is pretty messy.

In light of these problems (in particular, point 3), we should implement
stream mode netlink at some point.  In the mean time, here is a patch
that implements synchronous processing.  

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
[PATCH] ARM: 2661/1: imxfb include

Patch from Sascha Hauer

This patch adds the missing include files for the i.MX framebuffer
driver.

Signed-off-by: Sascha Hauer
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[PATCH] ARM: 2662/1: missing "default y" for CONFIG_HAS_TLS_REG

Patch from Nicolas Pitre

Signed-off-by: Nicolas Pitre
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Merge of master.kernel.org:/home/rmk/linux-2.6-rmk.git
[NETLINK]: Fix infinite loops in synchronous netlink changes.

The qlen should continue to decrement, even if we
pop partially processed SKBs back onto the receive queue.

Signed-off-by: David S. Miller <davem@davemloft.net>
[IA64] perfmon & PAL_HALT again

The pmu_active test is based on the values of PSR.up. THIS IS THE PROBLEM as
it does not take into account the lazy restore logic which is as follow (simplified):

context switch out:
	save PMDs
	clear psr.up
	release ownership

context switch in:
	if (ctx->last_cpu == smp_processor_id() && ctx->cpu_activation == cpu_activation) {
		set psr.up
		return
	}
	restore PMD
	restore PMC
	ctx->last_cpu   = smp_processor_id();
	ctx->activation = ++cpu_activation;
	set psr.up

The key here is that on context switch out, we clear psr.up and on context switch in
we check if nobody else used the PMU on that processor since last time we came. In
that case, we assume the PMD/PMC are ours and we simply reactivate.

The Caliper problem is that between the moment we context switch out and the moment we
come back, nobody effectively used the PMU BUT the processor went idle. Normally this
would have no incidence but PAL_HALT does alter the PMU registers.  In default_idle(),
the test on psr.up is not strong enough to cover this case and we go into PAL which
trashed the PMU resgisters. When we come back we falsely assume that this is our state
yet it is corrupted. Very nasty indeed.

To avoid the problem it is necessary to forbid going to PAL_HALT as soon as perfmon
installs some valid state in the PMU registers. This happens with an application
attaches a context to a thread or CPU. It is not enough to check the psr/dcr bits.
Hence I propose the attached patch. It adds a callback in process.c to modify the
condition to enter PAL on idle. Basically, now it is conditional to pal_halt=1 AND
perfmon saying it is okay.

Signed-off-by: Tony Luck <tony.luck@intel.com>
[IA64] another perfmon fix (take2)

- pfm_context_load(): change return value from EINVAL to EBUSY
  when context is already loaded.

- pfm_check_task_state(): pass test if context state is MASKED.
  It is safe to give access on PFM_CTX_MASKED because the PMU
  state (PMD) is stable and saved in software state.
  This helps multiplexing programs such as the example given
  in libpfm-3.1.

Signed-off-by: stephane eranian <eranian@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[XFRM/RTNETLINK]: Decrement qlen properly in {xfrm_,rt}netlink_rcv().

If we free up a partially processed packet because it's
skb->len dropped to zero, we need to decrement qlen because
we are dropping out of the top-level loop so it will do
the decrement for us.

Spotted by Herbert Xu.

Signed-off-by: David S. Miller <davem@davemloft.net>
[NET]: Disable queueing when carrier is lost.

Some network drivers call netif_stop_queue() when detecting loss of
carrier. This leads to packets being queued up at the qdisc level for
an unbound period of time. In order to prevent this effect, the core
networking stack will now cease to queue packets for any device, that
is operationally down (i.e. the queue is flushed and disabled).

Signed-off-by: Tommy S. Christensen <tommy.christensen@tpack.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
[NETFILTER]: Fix nf_debug_ip_local_deliver()

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
[NETFILTER]: Drop conntrack reference in ip_dev_loopback_xmit()

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
[IA64] Fix two warnings introduced by perfmon patches.

Signed-off-by: Tony Luck <tony.luck@intel.com>
[PKT_SCHED]: netetm: trap infinite loop hange on qlen underflow

Due to bugs in netem (fixed by later patches), it is possible to get qdisc
qlen to go negative. If this happens the CPU ends up spinning forever
in qdisc_run(). So add a BUG_ON() to trap it.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[PKT_SCHED]: netetm: make qdisc friendly to outer disciplines

Netem currently dumps packets into the queue when timer expires. This
patch makes work by self-clocking (more like TBF).  It fixes a bug
when 0 delay is requested (only doing loss or duplication).

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[PKT_SCHED]: netetm: adjust parent qlen when duplicating

Fix qlen underrun when doing duplication with netem. If netem is used
as leaf discipline, then the parent needs to be tweaked when packets
are duplicated.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[IPSEC]: Store idev entries

I found a bug that stopped IPsec/IPv6 from working.  About
a month ago IPv6 started using rt6i_idev->dev on the cached socket dst
entries.  If the cached socket dst entry is IPsec, then rt6i_idev will
be NULL.

Since we want to look at the rt6i_idev of the original route in this
case, the easiest fix is to store rt6i_idev in the IPsec dst entry just
as we do for a number of other IPv6 route attributes.  Unfortunately
this means that we need some new code to handle the references to
rt6i_idev.  That's why this patch is bigger than it would otherwise be.

I've also done the same thing for IPv4 since it is conceivable that
once these idev attributes start getting used for accounting, we
probably need to dereference them for IPv4 IPsec entries too.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
[IA64] Update arch/ia64/configs/tiger_defconfig

Kristen did most of the checking, bring this up to -rc2.

Signed-off-by: Tony Luck <tony.luck@intel.com>
[PKT_SCHED]: Action repeat

Long standing bug.
Policy to repeat an action never worked.

Signed-off-by: J Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge of rsync://rsync.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6.git/