netfilter: xt_qtaguid: add uid permission checks during ctrl/stats access

* uid handling
 - Limit UID impersonation to processes with a gid in AID_NET_BW_ACCT.
   This affects socket tagging, and data removal.
 - Limit stats lookup to own uid or the process gid is in AID_NET_BW_STATS.
   This affects stats lookup.

* allow pacifying the module
  Setting passive to Y/y will make the module return immediately on
  external stimulus.
  No more stats and silent success on ctrl writes.
  Mainly used when one suspects this module of misbehaving.

Change-Id: I83990862d52a9b0922aca103a0f61375cddeb7c4
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: qtaguid: disable #define DEBUG

This would cause log spam to the point of slowing down the system.

Change-Id: I5655f0207935004b0198f43ad0d3c9ea25466e4e
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: add counter sets and matching control

* Added support for sets of counters.
By default set 0 is active.
Userspace can control which set is active for a given UID by
writing to .../ctrl
   s <set_num> <uid>
Changing the active set is only permitted for processes in the
 AID_NET_BW_ACCT group.

The active set tracking is reset when the uid tag is deleted with
the .../ctrl command
  d 0 <uid>

* New output format for the proc .../stats
 - Now has cnt_set in the list.
  """
  idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packets rx_tcp_packets rx_tcp_bytes rx_udp_packets rx_udp_bytes rx_other_packets rx_other_bytes tx_tcp_packets tx_tcp_bytes tx_udp_packets tx_udp_bytes tx_other_packets tx_other_bytes
  ...
  2 rmnet0 0x0 1000 0 27729 29 1477 27 27501 26 228 3 0 0 1249 24 228 3 0 0
  2 rmnet0 0x0 1000 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
  3 rmnet0 0x0 10005 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
  3 rmnet0 0x0 10005 1 46407 57 8008 64 46407 57 0 0 0 0 8008 64 0 0 0 0
  ...
  6 rmnet0 0x7fff000100000000 10005 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
  6 rmnet0 0x7fff000100000000 10005 1 27493 24 1564 22 27493 24 0 0 0 0 1564 22 0 0 0 0
  """

* Refactored for proc stats output code.
* Silenced some of the per packet debug output.
* Reworded some of the debug messages.
* Replaced all the spin_lock_irqsave/irqrestore with *_bh():
   netfilter handling is done in softirq.

Change-Id: Ibe89f9d754579fd97335617186c614b43333cfd3
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: recognize IPV6 interfaces. root is procfs privileged.

* Allow tracking interfaces that only have an ipv6 address.
  Deal with ipv6 notifier chains that do NETDEV_UP without the rtnl_lock()
* Allow root all access to procfs ctrl/stats.
  To disable all checks:
    echo 0 > /sys/module/xt_qtaguid/parameters/ctrl_write_gid
    echo 0 > /sys/module/xt_qtaguid/parameters/stats_readall_gid
* Add CDEBUG define to enable pr_debug output specific to
    procfs ctrl/stats access.

Change-Id: I9a469511d92fe42734daff6ea2326701312a161b
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: Fix socket refcounts when tagging

* Don't hold the sockets after tagging.
  sockfd_lookup() does a get() on the associated file.
  There was no matching put() so a closed socket could never be
  freed.
* Don't rely on struct member order for tag_node
  The structs that had a struct tag_node member would work with
  the *_tree_* routines only because tag_node was 1st.
* Improve debug messages
  Provide info on who the caller is. Use unsigned int for uid.
* Only process NETDEV_UP events.
* Pacifier: disable netfilter matching. Leave .../stats header.

Change-Id: Iccb8ae3cca9608210c417597287a2391010dff2c
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: Fix sockfd_put() call within spinlock

sockfd_put() risks sleeping.
So when doing a delete ctrl command, defer the sockfd_put() and
kfree() to outside of the spinlock.

Change-Id: I5f8ab51d05888d885b2fbb035f61efa5b7abb88a
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: add some tagging/matching stats

/proc/net/xt_qtaguid/ctrl will now show:
  active tagged sockets: lines of "sock=%p tag=0x%llx (uid=%u)"
  sockets_tagged, : the number of sockets successfully tagged.
  sockets_untagged: the number of sockets successfully untagged.
  counter_set_changes: ctrl counter set change requests.
  delete_cmds: ctrl delete commands completed.
  iface_events: number of NETDEV_* events handled.
  match_found_sk: sk found in skbuff without ct assist.
  match_found_sk_in_ct: the number of times the connection tracker found
    a socket for us. This happens when the skbuff didn't have info.
  match_found_sk_none: the number of times no sk could be determined
    successfully looked up. This indicates we don't know who the
    data actually belongs to. This could be unsolicited traffic.

Change-Id: I3a65613bb24852e1eea768ab0320a6a7073ab9be
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: fix dev_stats for missing NETDEV_UNREGISTER

Turns out that some devices don't call the notifier chains
with NETDEV_UNREGISTER.
So now we only track up/down as the points for tracking
active/inactive transitions and saving the get_dev_stats().

Change-Id: I948755962b4c64150b4d04f294fb4889f151e42b
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: qtaguid: fix proc/.../stats uid filtered output

"cat /proc/net/xt_qtaguid/stats"
for a non-priviledged UID would output multiple twice its own stats.
The fix tweaks the way lines are counted.

Non-root:
  idx iface acct_tag_hex uid_tag_int cnt_set ...
  2 wlan0 0x0 10022 0 ...
  3 wlan0 0x0 10022 1 ...
  4 wlan0 0x3010000000000000 10022 0 ...
  5 wlan0 0x3010000000000000 10022 1 ...

Root:
  idx iface acct_tag_hex uid_tag_int cnt_set
  2 wlan0 0x0 0 0 ...
  3 wlan0 0x0 0 1 ...
  4 wlan0 0x0 1000 0 ...
  ...
  12 wlan0 0x0 10022 0 ...
  13 wlan0 0x0 10022 1 ...
  ...
  18 wlan0 0x3010000000000000 10022 0 ...
  19 wlan0 0x3010000000000000 10022 1 ...

Change-Id: I3cae1f4fee616bc897831350374656b0c718c45b
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: 1st pass at tracking tag based data resources

* Added global resource tracking based on tags.
 - Can be put into passive mode via
    /sys/modules/xt_qtaguid/params/tag_tracking_passive
 - The number of socket tags per UID is now limited
 - Adding /dev/xt_qtaguid that each process should open before starting
to tag sockets. A later change will make it a "must".
 - A process should not create new tags unless it has the dev open.
  A later change will make it a must.
 - On qtaguid_resources release, the process' matching socket tag info
  is deleted.
* Support run-time debug mask via /sys/modules parameter "debug_mask".
* split module into prettyprinting code, includes, main.
* Removed ptrdiff_t usage which didn't work in all cases.

Change-Id: I4a21d3bea55d23c1c3747253904e2a79f7d555d9
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: warn only once for missing proc qtaguid data

When a process doesn't have /dev/xt_qtaguid open, only warn once
instead of for every ctrl access.

Change-Id: I98a462a8731254ddc3bf6d2fefeef9823659b1f0
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: work around devices that reset their stats

Most net devs will not reset their stats when just going down/up,
unless a NETDEV_UNREGISTER was notified.
But some devs will not send out a NETDEV_UNREGISTER but still
reset their stats just before a NETDEV_UP.
Now we just track the dev stats during NETDEV_DOWN... just in case.
Then on NETDEV_UP we check the stats: if the device didn't do a
NETDEV_UNREGISTER and a prior NETDEV_DOWN captured stats, then we treat
it as an UNREGISTER and save the totals from the stashed values.

Added extra netdev event debugging.

Change-Id: Iec79e74bfd40269aa3e5892f161be71e09de6946
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: provide an iface_stat_all proc entry

There is a
  /proc/net/xt_qtaguid/iface/<iface>/{rx_bytes,rx_packets,tx_bytes,...}
but for better convenience and to avoid getting overly stale net/dev stats
we now have
  /proc/net/xt_qtaguid/iface_stat_all
which outputs lines of:
  iface_name active rx_bytes rx_packets tx_bytes tx_packets
    net_dev_rx_bytes net_dev_rx_packets net_dev_tx_bytes net_dev_tx_packets

Change-Id: I12cc10d2d123b86b56d4eb489b1d77b2ce72ebcf
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: change WARN_ONCE into pr_warn_once

Make the warning less scary.

Change-Id: I0276c5413e37ec991f24db57aeb90333fb1b5a65
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: fix crash after using delete ctrl command

* Crash fix
The delete command would delete a socket tag entry without removing it
from the proc_qtu_data { ..., sock_tag_list, }.
This in turn would cause an exiting process to crash while cleaning up
its matching proc_qtu_data.

* Added more aggressive tracking/cleanup of proc_qtu_data
This should allow one process to cleanup qtu_tag_data{} left around from
processes that didn't use resource tracking via /dev/xt_qtaguid.

* Debug printing tweaks
Better code inclusion/exclusion handling,
and extra debug out of full state.

Change-Id: I735965af2962ffcd7f3021cdc0068b3ab21245c2
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: add missing tracking for no filp case

In cases where the skb would have an sk_socket but no file, that skb
would not be counted at all. Assigning to uid 0 now.

Adding extra counters to track skb counts.

Change-Id: If049b4b525e1fbd5afc9c72b4a174c0a435f2ca7
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: Fix the stats info display order

Change-Id: I3bf165c31f35a6c7dc212f23df5eefaeb8129d0d
Signed-off-by: Ashish Sharma <ashishsharma@google.com>
netfilter: xt_qtaguid: fix crash on ctrl delete command

Because for now the xt_qtaguid module allows procs to use tags without
having /dev/xt_qtaguid open, there was a case where it would try
to delete a resources from a list that was proc specific.
But that resource was never added to that list which is only
used when /dev/xt_qtaguid has been opened by the proc.

Once our userspace is fully updated, we won't need those exceptions.

Change-Id: Idd4bfea926627190c74645142916e10832eb2504
Signed-off-by: JP Abgrall <jpa@google.com>
net: percpu net_device refcount

We tried very hard to remove all possible dev_hold()/dev_put() pairs in
network stack, using RCU conversions.

There is still an unavoidable device refcount change for every dst we
create/destroy, and this can slow down some workloads (routers or some
app servers, mmap af_packet)

We can switch to a percpu refcount implementation, now dynamic per_cpu
infrastructure is mature. On a 64 cpus machine, this consumes 256 bytes
per device.

On x86, dev_hold(dev) code :

before
        lock    incl 0x280(%ebx)
after:
        movl    0x260(%ebx),%eax
        incl    fs:(%eax)

Stress bench :

(Sending 160.000.000 UDP frames,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_TRIE)

Before:

real    1m1.662s
user    0m14.373s
sys     12m55.960s

After:

real    0m51.179s
user    0m15.329s
sys     10m15.942s

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netfilter: use NFPROTO_IPV4 instead of AF_INET

The field family of xt_target should be NFPROTO_IPV4, though
NFPROTO_IPV4 and AF_INET are the same.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>