We currently use a percpu spinlock to 'protect' rule bytes/packets
counters, after various attempts to use RCU instead.

Lately we added a seqlock so that get_counters() can run without
blocking BH or 'writers'. But we really only need the seqcount in it.

Spinlock itself is only locked by the current/owner cpu, so we can
remove it completely.

This cleanups api, using correct 'writer' vs 'reader' semantic.

At replace time, the get_counters() call makes sure all cpus are done
using the old table.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

commit f3c5c1bf (make ip_tables reentrant) introduced a race in
handling the stackptr restore, at the end of ipt_do_table()

We should do it before the call to xt_info_rdunlock_bh(), or we allow
cpu preemption and another cpu overwrites stackptr of original one.

A second fix is to change the underflow test to check the origptr value
instead of 0 to detect underflow, or else we allow a jump from different
hooks.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Structures ipt_replace, compat_ipt_replace, and xt_get_revision are
copied from userspace.  Fields of these structs that are
zero-terminated strings are not checked.  When they are used as argument
to a format string containing "%s" in request_module(), some sensitive
information is leaked to userspace via argument of spawned modprobe
process.

The first and the third bugs were introduced before the git epoch; the
second was introduced in 2722971c (v2.6.17-rc1).  To trigger the bug
one should have CAP_NET_ADMIN.
Signed-off-by: NVasiliy Kulikov <segoon@openwall.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

One iptables invocation with 135000 rules takes 35 seconds of cpu time
on a recent server, using a 32bit distro and a 64bit kernel.

We eventually trigger NMI/RCU watchdog.

INFO: rcu_sched_state detected stall on CPU 3 (t=6000 jiffies)

COMPAT mode has quadratic behavior and consume 16 bytes of memory per
rule.

Switch the xt_compat algos to use an array instead of list, and use a
binary search to locate an offset in the sorted array.

This halves memory need (8 bytes per rule), and removes quadratic
behavior [ O(N*N) -> O(N*log2(N)) ]

Time of iptables goes from 35 s to 150 ms.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Using "iptables -L" with a lot of rules have a too big BH latency.
Jesper mentioned ~6 ms and worried of frame drops.

Switch to a per_cpu seqlock scheme, so that taking a snapshot of
counters doesnt need to block BH (for this cpu, but also other cpus).

This adds two increments on seqlock sequence per ipt_do_table() call,
its a reasonable cost for allowing "iptables -L" not block BH
processing.
Reported-by: NJesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Acked-by: NJesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Structure ipt_getinfo is copied to userland with the field "name"
that has the last elements unitialized.  It leads to leaking of
contents of kernel stack memory.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Many of the used macros are just there for userspace compatibility.
Substitute the in-kernel code to directly use the terminal macro
and stuff the defines into #ifndef __KERNEL__ sections.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

commit f3c5c1bf
(netfilter: xtables: make ip_tables reentrant) forgot to
also compute the jumpstack size in the compat handlers.

Result is that "iptables -I INPUT -j userchain" turns into -j DROP.

Reported by Sebastian Roesner on #netfilter, closes
http://bugzilla.netfilter.org/show_bug.cgi?id=669.

Note: arptables change is compile-tested only.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Tested-by: NMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit 24b36f01 (netfilter: {ip,ip6,arp}_tables: dont block
bottom half more than necessary), lockdep can raise a warning
because we attempt to lock a spinlock with BH enabled, while
the same lock is usually locked by another cpu in a softirq context.

Disable again BH to avoid these lockdep warnings.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Diagnosed-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently disable BH for the whole duration of get_counters()

On machines with a lot of cpus and large tables, this might be too long.

We can disable preemption during the whole function, and disable BH only
while fetching counters for the current cpu.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Use skb->len for accounting as xt_quota does.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Using vmalloc_node(size, numa_node_id()) for temporary storage is not
needed. vmalloc(size) is more respectful of user NUMA policy.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

commit f3c5c1bf (netfilter: xtables: make ip_tables reentrant)
introduced a performance regression, because stackptr array is shared by
all cpus, adding cache line ping pongs. (16 cpus share a 64 bytes cache
line)

Fix this using alloc_percpu()
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-By: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Make sure all printk messages have a severity level.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Change netfilter asserts to standard WARN_ON. This has the
benefit of backtrace info and also causes netfilter errors
to show up on kerneloops.org.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Prepare the arrays for use with the multiregister function. The
future layer-3 xt matches can then be easily added to it without
needing more (un)register code.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Since xt_action_param is writable, let's use it. The pointer to
'bool hotdrop' always worried (8 bytes (64-bit) to write 1 byte!).
Surprisingly results in a reduction in size:

   text    data     bss filename
5457066  692730  357892 vmlinux.o-prev
5456554  692730  357892 vmlinux.o
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

In future, layer-3 matches will be an xt module of their own, and
need to set the fragoff and thoff fields. Adding more pointers would
needlessy increase memory requirements (esp. so for 64-bit, where
pointers are wider).
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

The structures carried - besides match/target - almost the same data.
It is possible to combine them, as extensions are evaluated serially,
and so, the callers end up a little smaller.

  text  data  bss  filename
-15318   740  104  net/ipv4/netfilter/ip_tables.o
+15286   740  104  net/ipv4/netfilter/ip_tables.o
-15333   540  152  net/ipv6/netfilter/ip6_tables.o
+15269   540  152  net/ipv6/netfilter/ip6_tables.o
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

We want to be able to use CONFIG_DYNAMIC_DEBUG in netfilter code, switch
the few existing pr_devel() calls to pr_debug().
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Currently, the table traverser stores return addresses in the ruleset
itself (struct ip6t_entry->comefrom). This has a well-known drawback:
the jumpstack is overwritten on reentry, making it necessary for
targets to return absolute verdicts. Also, the ruleset (which might
be heavy memory-wise) needs to be replicated for each CPU that can
possibly invoke ip6t_do_table.

This patch decouples the jumpstack from struct ip6t_entry and instead
puts it into xt_table_info. Not being restricted by 'comefrom'
anymore, we can set up a stack as needed. By default, there is room
allocated for two entries into the traverser.

arp_tables is not touched though, because there is just one/two
modules and further patches seek to collapse the table traverser
anyhow.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

The following semantic patch does part of the transformation:
// <smpl>
@ rule1 @
struct xt_match ops;
identifier check;
@@
 ops.checkentry = check;

@@
identifier rule1.check;
@@
 check(...) { <...
-return true;
+return 0;
 ...> }

@@
identifier rule1.check;
@@
 check(...) { <...
-return false;
+return -EINVAL;
 ...> }
// </smpl>
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Restore function signatures from bool to int so that we can report
memory allocation failures or similar using -ENOMEM rather than
always having to pass -EINVAL back.

This semantic patch may not be too precise (checking for functions
that use xt_mtchk_param rather than functions referenced by
xt_match.checkentry), but reviewed, it produced the intended result.

// <smpl>
@@
type bool;
identifier check, par;
@@
-bool check
+int check
 (struct xt_mtchk_param *par) { ... }
// </smpl>
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Supplement to 1159683e.

Downgrade the log level to INFO for most checkentry messages as they
are, IMO, just an extra information to the -EINVAL code that is
returned as part of a parameter "constraint violation". Leave errors
to real errors, such as being unable to create a LED trigger.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Just pass in the entire repl struct. In case of a new table (e.g.
ip6t_register_table), the repldata has been previously filled with
table->name and table->size already (in ip6t_alloc_initial_table).
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

The macro is replaced by a list.h-like foreach loop. This makes
the code more inspectable.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

The macro is replaced by a list.h-like foreach loop. This makes
the code much more inspectable.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

This should make it easier to remove redundant arguments later.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NJan Engelhardt <jengelh@medozas.de>