linux-stable.git/include, branch v3.16.72

netfilter: ctnetlink: don't use conntrack/expect object addresses as id

2019-08-13T11:39:32+00:00

commit 3c79107631db1f7fd32cf3f7368e4672004a3010 upstream.

else, we leak the addresses to userspace via ctnetlink events
and dumps.

Compute an ID on demand based on the immutable parts of nf_conn struct.

Another advantage compared to using an address is that there is no
immediate re-use of the same ID in case the conntrack entry is freed and
reallocated again immediately.

Fixes: 3583240249ef ("[NETFILTER]: nf_conntrack_expect: kill unique ID")
Fixes: 7f85f914721f ("[NETFILTER]: nf_conntrack: kill unique ID")
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
[bwh: Backported to 3.16:
 - Include  in nf_conntrack_core.c
 - Adjust context]
Signed-off-by: Ben Hutchings

inet: switch IP ID generator to siphash

2019-08-13T11:39:32+00:00

commit df453700e8d81b1bdafdf684365ee2b9431fb702 upstream.

According to Amit Klein and Benny Pinkas, IP ID generation is too weak
and might be used by attackers.

Even with recent net_hash_mix() fix (netns: provide pure entropy for net_hash_mix())
having 64bit key and Jenkins hash is risky.

It is time to switch to siphash and its 128bit keys.

Signed-off-by: Eric Dumazet 
Reported-by: Amit Klein 
Reported-by: Benny Pinkas 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

siphash: add cryptographically secure PRF

2019-08-13T11:39:32+00:00

commit 2c956a60778cbb6a27e0c7a8a52a91378c90e1d1 upstream.

SipHash is a 64-bit keyed hash function that is actually a
cryptographically secure PRF, like HMAC. Except SipHash is super fast,
and is meant to be used as a hashtable keyed lookup function, or as a
general PRF for short input use cases, such as sequence numbers or RNG
chaining.

For the first usage:

There are a variety of attacks known as "hashtable poisoning" in which an
attacker forms some data such that the hash of that data will be the
same, and then preceeds to fill up all entries of a hashbucket. This is
a realistic and well-known denial-of-service vector. Currently
hashtables use jhash, which is fast but not secure, and some kind of
rotating key scheme (or none at all, which isn't good). SipHash is meant
as a replacement for jhash in these cases.

There are a modicum of places in the kernel that are vulnerable to
hashtable poisoning attacks, either via userspace vectors or network
vectors, and there's not a reliable mechanism inside the kernel at the
moment to fix it. The first step toward fixing these issues is actually
getting a secure primitive into the kernel for developers to use. Then
we can, bit by bit, port things over to it as deemed appropriate.

While SipHash is extremely fast for a cryptographically secure function,
it is likely a bit slower than the insecure jhash, and so replacements
will be evaluated on a case-by-case basis based on whether or not the
difference in speed is negligible and whether or not the current jhash usage
poses a real security risk.

For the second usage:

A few places in the kernel are using MD5 or SHA1 for creating secure
sequence numbers, syn cookies, port numbers, or fast random numbers.
SipHash is a faster and more fitting, and more secure replacement for MD5
in those situations. Replacing MD5 and SHA1 with SipHash for these uses is
obvious and straight-forward, and so is submitted along with this patch
series. There shouldn't be much of a debate over its efficacy.

Dozens of languages are already using this internally for their hash
tables and PRFs. Some of the BSDs already use this in their kernels.
SipHash is a widely known high-speed solution to a widely known set of
problems, and it's time we catch-up.

Signed-off-by: Jason A. Donenfeld 
Reviewed-by: Jean-Philippe Aumasson 
Cc: Linus Torvalds 
Cc: Eric Biggers 
Cc: David Laight 
Cc: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: hash net ptr into fragmentation bucket selection

2019-08-13T11:39:31+00:00

commit 5a352dd0a3aac03b443c94828dfd7144261c8636 upstream.

As namespaces are sometimes used with overlapping ip address ranges,
we should also use the namespace as input to the hash to select the ip
fragmentation counter bucket.

Cc: Eric Dumazet 
Cc: Flavio Leitner 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv4: hash net ptr into fragmentation bucket selection

2019-08-13T11:39:30+00:00

commit b6a7719aedd7e5c0f2df7641aa47386111682df4 upstream.

As namespaces are sometimes used with overlapping ip address ranges,
we should also use the namespace as input to the hash to select the ip
fragmentation counter bucket.

Cc: Eric Dumazet 
Cc: Flavio Leitner 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

ipv6: Make __ipv6_select_ident static

2019-08-13T11:39:30+00:00

commit 8381eacf5c3b35cf7755f4bc521c4d56d24c1cd9 upstream.

Make __ipv6_select_ident() static as it isn't used outside
the file.

Fixes: 0508c07f5e0c9 (ipv6: Select fragment id during UFO segmentation if not set.)
Signed-off-by: Vladislav Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: Select fragment id during UFO segmentation if not set.

2019-08-13T11:39:29+00:00

commit 0508c07f5e0c94f38afd5434e8b2a55b84553077 upstream.

If the IPv6 fragment id has not been set and we perform
fragmentation due to UFO, select a new fragment id.
We now consider a fragment id of 0 as unset and if id selection
process returns 0 (after all the pertrubations), we set it to
0x80000000, thus giving us ample space not to create collisions
with the next packet we may have to fragment.

When doing UFO integrity checking, we also select the
fragment id if it has not be set yet.   This is stored into
the skb_shinfo() thus allowing UFO to function correclty.

This patch also removes duplicate fragment id generation code
and moves ipv6_select_ident() into the header as it may be
used during GSO.

Signed-off-by: Vladislav Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

mm/page_alloc.c: calculate 'available' memory in a separate function

2019-08-13T11:39:28+00:00

commit d02bd27bd33dd7e8d22594cd568b81be0cb584cd upstream.

Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory
statistics protocol, corresponding to 'Available' in /proc/meminfo.

It indicates to the hypervisor how big the balloon can be inflated
without pushing the guest system to swap.  This metric would be very
useful in VM orchestration software to improve memory management of
different VMs under overcommit.

This patch (of 2):

Factor out calculation of the available memory counter into a separate
exportable function, in order to be able to use it in other parts of the
kernel.

In particular, it appears a relevant metric to report to the hypervisor
via virtio-balloon statistics interface (in a followup patch).

Signed-off-by: Igor Redko 
Signed-off-by: Denis V. Lunev 
Reviewed-by: Roman Kagan 
Cc: Michael S. Tsirkin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16 as dependency of commit a1078e821b60
 "xen: let alloc_xenballooned_pages() fail if not enough memory free"]
Signed-off-by: Ben Hutchings

USB: core: Fix bug caused by duplicate interface PM usage counter

2019-08-13T11:39:12+00:00

commit c2b71462d294cf517a0bc6e4fd6424d7cee5596f upstream.

The syzkaller fuzzer reported a bug in the USB hub driver which turned
out to be caused by a negative runtime-PM usage counter.  This allowed
a hub to be runtime suspended at a time when the driver did not expect
it.  The symptom is a WARNING issued because the hub's status URB is
submitted while it is already active:

	URB 0000000031fb463e submitted while active
	WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363

The negative runtime-PM usage count was caused by an unfortunate
design decision made when runtime PM was first implemented for USB.
At that time, USB class drivers were allowed to unbind from their
interfaces without balancing the usage counter (i.e., leaving it with
a positive count).  The core code would take care of setting the
counter back to 0 before allowing another driver to bind to the
interface.

Later on when runtime PM was implemented for the entire kernel, the
opposite decision was made: Drivers were required to balance their
runtime-PM get and put calls.  In order to maintain backward
compatibility, however, the USB subsystem adapted to the new
implementation by keeping an independent usage counter for each
interface and using it to automatically adjust the normal usage
counter back to 0 whenever a driver was unbound.

This approach involves duplicating information, but what is worse, it
doesn't work properly in cases where a USB class driver delays
decrementing the usage counter until after the driver's disconnect()
routine has returned and the counter has been adjusted back to 0.
Doing so would cause the usage counter to become negative.  There's
even a warning about this in the USB power management documentation!

As it happens, this is exactly what the hub driver does.  The
kick_hub_wq() routine increments the runtime-PM usage counter, and the
corresponding decrement is carried out by hub_event() in the context
of the hub_wq work-queue thread.  This work routine may sometimes run
after the driver has been unbound from its interface, and when it does
it causes the usage counter to go negative.

It is not possible for hub_disconnect() to wait for a pending
hub_event() call to finish, because hub_disconnect() is called with
the device lock held and hub_event() acquires that lock.  The only
feasible fix is to reverse the original design decision: remove the
duplicate interface-specific usage counter and require USB drivers to
balance their runtime PM gets and puts.  As far as I know, all
existing drivers currently do this.

Signed-off-by: Alan Stern 
Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com
Signed-off-by: Greg Kroah-Hartman 
[bwh: Backported to 3.16:
 - Adjust documentation filename
 - Don't add ReST markup in documentation
 - Update use of pm_usage_cnt in poseidon driver, which has been
   removed upstream]
Signed-off-by: Ben Hutchings

x86/kprobes: Verify stack frame on kretprobe

2019-08-13T11:39:11+00:00

commit 3ff9c075cc767b3060bdac12da72fc94dd7da1b8 upstream.

Verify the stack frame pointer on kretprobe trampoline handler,
If the stack frame pointer does not match, it skips the wrong
entry and tries to find correct one.

This can happen if user puts the kretprobe on the function
which can be used in the path of ftrace user-function call.
Such functions should not be probed, so this adds a warning
message that reports which function should be blacklisted.

Tested-by: Andrea Righi 
Signed-off-by: Masami Hiramatsu 
Acked-by: Steven Rostedt 
Cc: Linus Torvalds 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/155094059185.6137.15527904013362842072.stgit@devbox
Signed-off-by: Ingo Molnar 
Signed-off-by: Ben Hutchings