Commit 3bb398d925 ("netfilter: nf_ct_helper: disable automatic helper
assignment") is causing behavior regressions in firewalls, as traffic
handled by conntrack helpers is now by default not passed through even
though it was before due to missing CT targets (which were not necessary
before this commit).
The default had to be switched off due to security reasons [1] [2] and
therefore should stay the way it is, but let's be friendly to firewall
admins and issue a warning the first time we're in situation where packet
would be likely passed through with the old default but we're likely going
to drop it on the floor now.
Rewrite the code a little bit as suggested by Linus, so that we avoid
spaghettiing the code even more -- namely the whole decision making
process regarding helper selection (either automatic or not) is being
separated, so that the whole logic can be simplified and code (condition)
duplication reduced.
[1] https://cansecwest.com/csw12/conntrack-attack.pdf
[2] https://home.regit.org/netfilter-en/secure-use-of-helpers/
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Thomas reports its not possible to attach the H.245 helper:
iptables -t raw -A PREROUTING -p udp -j CT --helper H.245
iptables: No chain/target/match by that name.
xt_CT: No such helper "H.245"
This is because H.245 registers as NFPROTO_UNSPEC, but the CT target
passes NFPROTO_IPV4/IPV6 to nf_conntrack_helper_try_module_get.
We should treat UNSPEC as wildcard and ignore the l3num instead.
Reported-by: Thomas Woerner <twoerner@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
All of the callers of nf_hook_slow already hold the rcu_read_lock, so this
cleanup removes the recursive call. This is just a cleanup, as the locking
code gracefully handles this situation.
Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add nf_ct_helper_init(), nf_conntrack_helpers_register() and
nf_conntrack_helpers_unregister() functions to avoid repetitive
opencoded initialization in helpers.
This patch keeps an id parameter for nf_ct_helper_init() not to break
helper matching by name that has been inconsistently exposed to
userspace through ports, eg. ftp-2121, and through an incremental id,
eg. tftp-1.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
From: Liping Zhang <liping.zhang@spreadtrum.com>
Similar to ctnl_untimeout, when hash resize happened, we should try
to do unhelp from the 0# bucket again.
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following patchset contains Netfilter updates for net-next,
they are:
1) Don't use userspace datatypes in bridge netfilter code, from
Tobin Harding.
2) Iterate only once over the expectation table when removing the
helper module, instead of once per-netns, from Florian Westphal.
3) Extra sanitization in xt_hook_ops_alloc() to return error in case
we ever pass zero hooks, xt_hook_ops_alloc():
4) Handle NFPROTO_INET from the logging core infrastructure, from
Liping Zhang.
5) Autoload loggers when TRACE target is used from rules, this doesn't
change the behaviour in case the user already selected nfnetlink_log
as preferred way to print tracing logs, also from Liping Zhang.
6) Conntrack slabs with SLAB_HWCACHE_ALIGN to allow rearranging fields
by cache lines, increases the size of entries in 11% per entry.
From Florian Westphal.
7) Skip zone comparison if CONFIG_NF_CONNTRACK_ZONES=n, from Florian.
8) Remove useless defensive check in nf_logger_find_get() from Shivani
Bhardwaj.
9) Remove zone extension as place it in the conntrack object, this is
always include in the hashing and we expect more intensive use of
zones since containers are in place. Also from Florian Westphal.
10) Owner match now works from any namespace, from Eric Bierdeman.
11) Make sure we only reply with TCP reset to TCP traffic from
nf_reject_ipv4, patch from Liping Zhang.
12) Introduce --nflog-size to indicate amount of network packet bytes
that are copied to userspace via log message, from Vishwanath Pai.
This obsoletes --nflog-range that has never worked, it was designed
to achieve this but it has never worked.
13) Introduce generic macros for nf_tables object generation masks.
14) Use generation mask in table, chain and set objects in nf_tables.
This allows fixes interferences with ongoing preparation phase of
the commit protocol and object listings going on at the same time.
This update is introduced in three patches, one per object.
15) Check if the object is active in the next generation for element
deactivation in the rbtree implementation, given that deactivation
happens from the commit phase path we have to observe the future
status of the object.
16) Support for deletion of just added elements in the hash set type.
17) Allow to resize hashtable from /proc entry, not only from the
obscure /sys entry that maps to the module parameter, from Florian
Westphal.
18) Get rid of NFT_BASECHAIN_DISABLED, this code is not exercised
anymore since we tear down the ruleset whenever the netdevice
goes away.
19) Support for matching inverted set lookups, from Arturo Borrero.
20) Simplify the iptables_mangle_hook() by removing a superfluous
extra branch.
21) Introduce ether_addr_equal_masked() and use it from the netfilter
codebase, from Joe Perches.
22) Remove references to "Use netfilter MARK value as routing key"
from the Netfilter Kconfig description given that this toggle
doesn't exists already for 10 years, from Moritz Sichert.
23) Introduce generic NF_INVF() and use it from the xtables codebase,
from Joe Perches.
24) Setting logger to NONE via /proc was not working unless explicit
nul-termination was included in the string. This fixes seems to
leave the former behaviour there, so we don't break backward.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The expectation table is not duplicated per net namespace anymore, so we can move
the expectation table and conntrack table iteration out of the per-net loop.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for your net tree,
they are:
1) Fix incorrect timestamp in nfnetlink_queue introduced when addressing
y2038 safe timestamp, from Florian Westphal.
2) Get rid of leftover conntrack definition from the previous merge
window, oneliner from Florian.
3) Make nf_queue handler pernet to resolve race on dereferencing the
hook state structure with netns removal, from Eric Biederman.
4) Ensure clean exit on unregistered helper ports, from Taehee Yoo.
5) Restore FLOWI_FLAG_KNOWN_NH in nf_dup_ipv6. This got lost while
generalizing xt_TEE to add packet duplication support in nf_tables,
from Paolo Abeni.
6) Insufficient netlink NFTA_SET_TABLE attribute check in
nf_tables_getset(), from Phil Turnbull.
7) Reject helper registration on duplicated ports via modparams.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't allow registration of helpers using the same tuple:
{ l3proto, l4proto, src-port }
We lookup for the helper from the packet path using this tuple through
__nf_ct_helper_find(). Therefore, we have to avoid having two helpers
with the same tuple to ensure predictible behaviour.
Don't compare the helper string names anymore since it is valid to
register two helpers with the same name, but using different tuples.
This is also implicitly fixing up duplicated helper registration via
ports= modparam since the name comparison was defeating the tuple
duplication validation.
Reported-by: Feng Gao <gfree.wind@gmail.com>
Reported-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We already include netns address in the hash and compare the netns pointers
during lookup, so even if namespaces have overlapping addresses entries
will be spread across the expectation table.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We already include netns address in the hash and compare the netns pointers
during lookup, so even if namespaces have overlapping addresses entries
will be spread across the table.
Assuming 64k bucket size, this change saves 0.5 mbyte per namespace on a
64bit system.
NAT bysrc and expectation hash is still per namespace, those will
changed too soon.
Future patch will also make conntrack object slab cache global again.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Four years ago we introduced a new sysctl knob to disable automatic
helper assignment in 72110dfaa907 ("netfilter: nf_ct_helper: disable
automatic helper assignment"). This knob kept this behaviour enabled by
default to remain conservative.
This measure was introduced to provide a secure way to configure
iptables and connection tracking helpers through explicit rules.
Give the time we have waited for this, let's turn off this by default
now, worse case users still have a chance to recover the former
behaviour by explicitly enabling this back through sysctl.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When we need to lock all buckets in the connection hashtable we'd attempt to
lock 1024 spinlocks, which is way more preemption levels than supported by
the kernel. Furthermore, this behavior was hidden by checking if lockdep is
enabled, and if it was - use only 8 buckets(!).
Fix this by using a global lock and synchronize all buckets on it when we
need to lock them all. This is pretty heavyweight, but is only done when we
need to resize the hashtable, and that doesn't happen often enough (or at all).
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
nf_conntrack_lock is a monolithic lock and suffers from huge contention
on current generation servers (8 or more core/threads).
Perf locking congestion is clear on base kernel:
- 72.56% ksoftirqd/6 [kernel.kallsyms] [k] _raw_spin_lock_bh
- _raw_spin_lock_bh
+ 25.33% init_conntrack
+ 24.86% nf_ct_delete_from_lists
+ 24.62% __nf_conntrack_confirm
+ 24.38% destroy_conntrack
+ 0.70% tcp_packet
+ 2.21% ksoftirqd/6 [kernel.kallsyms] [k] fib_table_lookup
+ 1.15% ksoftirqd/6 [kernel.kallsyms] [k] __slab_free
+ 0.77% ksoftirqd/6 [kernel.kallsyms] [k] inet_getpeer
+ 0.70% ksoftirqd/6 [nf_conntrack] [k] nf_ct_delete
+ 0.55% ksoftirqd/6 [ip_tables] [k] ipt_do_table
This patch change conntrack locking and provides a huge performance
improvement. SYN-flood attack tested on a 24-core E5-2695v2(ES) with
10Gbit/s ixgbe (with tool trafgen):
Base kernel: 810.405 new conntrack/sec
After patch: 2.233.876 new conntrack/sec
Notice other floods attack (SYN+ACK or ACK) can easily be deflected using:
# iptables -A INPUT -m state --state INVALID -j DROP
# sysctl -w net/netfilter/nf_conntrack_tcp_loose=0
Use an array of hashed spinlocks to protect insertions/deletions of
conntracks into the hash table. 1024 spinlocks seem to give good
results, at minimal cost (4KB memory). Due to lockdep max depth,
1024 becomes 8 if CONFIG_LOCKDEP=y
The hash resize is a bit tricky, because we need to take all locks in
the array. A seqcount_t is used to synchronize the hash table users
with the resizing process.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Netfilter expectations are protected with the same lock as conntrack
entries (nf_conntrack_lock). This patch split out expectations locking
to use it's own lock (nf_conntrack_expect_lock).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
One spinlock per cpu to protect dying/unconfirmed/template special lists.
(These lists are now per cpu, a bit like the untracked ct)
Add a @cpu field to nf_conn, to make sure we hold the appropriate
spinlock at removal time.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add copyright statements to all netfilter files which have had significant
changes done by myself in the past.
Some notes:
- nf_conntrack_ecache.c was incorrectly attributed to Rusty and Netfilter
Core Team when it got split out of nf_conntrack_core.c. The copyrights
even state a date which lies six years before it was written. It was
written in 2005 by Harald and myself.
- net/ipv{4,6}/netfilter.c, net/netfitler/nf_queue.c were missing copyright
statements. I've added the copyright statement from net/netfilter/core.c,
where this code originated
- for nf_conntrack_proto_tcp.c I've also added Jozsef, since I didn't want
it to give the wrong impression
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds netns support to nf_log and it prepares netns
support for existing loggers. It is composed of four major
changes.
1) nf_log_register has been split to two functions: nf_log_register
and nf_log_set. The new nf_log_register is used to globally
register the nf_logger and nf_log_set is used for enabling
pernet support from nf_loggers.
Per netns is not yet complete after this patch, it comes in
separate follow up patches.
2) Add net as a parameter of nf_log_bind_pf. Per netns is not
yet complete after this patch, it only allows to bind the
nf_logger to the protocol family from init_net and it skips
other cases.
3) Adapt all nf_log_packet callers to pass netns as parameter.
After this patch, this function only works for init_net.
4) Make the sysctl net/netfilter/nf_log pernet.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
The following patchset contains Netfilter fixes for your net tree,
they are:
* Don't generate audit log message if audit is not enabled, from Gao Feng.
* Fix logging formatting for packets dropped by helpers, by Joe Perches.
* Fix a compilation warning in nfnetlink if CONFIG_PROVE_RCU is not set,
from Paul Bolle.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Update nf_ct_helper_log to emit args along with the format.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pablo Neira Ayuso says:
====================
The following patchset contain updates for your net-next tree, they are:
* Fix (for just added) connlabel dependencies, from Florian Westphal.
* Add aliasing support for conntrack, thus users can either use -m state
or -m conntrack from iptables while using the same kernel module, from
Jozsef Kadlecsik.
* Some code refactoring for the CT target to merge common code in
revision 0 and 1, from myself.
* Add aliasing support for CT, based on patch from Jozsef Kadlecsik.
* Add one mutex per nfnetlink subsystem, from myself.
* Improved logging for packets that are dropped by helpers, from myself.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull in 'net' to take in the bug fixes that didn't make it into
3.8-final.
Also, deal with the semantic conflict of the change made to
net/ipv6/xfrm6_policy.c A missing rt6->n neighbour release
was added to 'net', but in 'net-next' we no longer cache the
neighbour entries in the ipv6 routes so that change is not
appropriate there.
Signed-off-by: David S. Miller <davem@davemloft.net>
Connection tracking helpers have to drop packets under exceptional
situations. Currently, the user gets the following logging message
in case that happens:
nf_ct_%s: dropping packet ...
However, depending on the helper, there are different reasons why a
packet can be dropped.
This patch modifies the existing code to provide more specific
error message in the scope of each helper to help users to debug
the reason why the packet has been dropped, ie:
nf_ct_%s: dropping packet: reason ...
Thanks to Joe Perches for many formatting suggestions.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
commit (32f5376 netfilter: nf_ct_helper: disable automatic helper
re-assignment of different type) broke transparent proxy scenarios.
For example, initial helper lookup might yield "ftp" (dport 21),
while re-lookup after REDIRECT yields "ftp-2121".
This causes the autoassign code to toss the ftp helper, even
though these are just different instances of the same helper.
Change the test to check for the helper function address instead
of the helper address, as suggested by Pablo.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
Move the global initial codes to the module_init/exit context.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
In preparation for supporting the creation of network namespaces
by unprivileged users, modify all of the per net sysctl exports
and refuse to allow them to unprivileged users.
This makes it safe for unprivileged users in general to access
per net sysctls, and allows sysctls to be exported to unprivileged
users on an individual basis as they are deemed safe.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch modifies __nf_ct_try_assign_helper in a way that invalidates support
for the following scenario:
1) attach the helper A for first time when the conntrack is created
2) attach new (different) helper B due to changes the reply tuple caused by NAT
eg. port redirection from TCP/21 to TCP/5060 with both FTP and SIP helpers
loaded, which seems to be a quite unorthodox scenario.
I can provide a more elaborated patch to support this scenario but explicit
helper attachment provides a better solution for this since now the use can
attach the helpers consistently, without relying on the automatic helper
lookup magic.
This patch fixes a possible out of bound zeroing of the conntrack helper
extension if the helper B uses more memory for its private data than
helper A.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
There are good reasons to supports helpers in user-space instead:
* Rapid connection tracking helper development, as developing code
in user-space is usually faster.
* Reliability: A buggy helper does not crash the kernel. Moreover,
we can monitor the helper process and restart it in case of problems.
* Security: Avoid complex string matching and mangling in kernel-space
running in privileged mode. Going further, we can even think about
running user-space helpers as a non-root process.
* Extensibility: It allows the development of very specific helpers (most
likely non-standard proprietary protocols) that are very likely not to be
accepted for mainline inclusion in the form of kernel-space connection
tracking helpers.
This patch adds the infrastructure to allow the implementation of
user-space conntrack helpers by means of the new nfnetlink subsystem
`nfnetlink_cthelper' and the existing queueing infrastructure
(nfnetlink_queue).
I had to add the new hook NF_IP6_PRI_CONNTRACK_HELPER to register
ipv[4|6]_helper which results from splitting ipv[4|6]_confirm into
two pieces. This change is required not to break NAT sequence
adjustment and conntrack confirmation for traffic that is enqueued
to our user-space conntrack helpers.
Basic operation, in a few steps:
1) Register user-space helper by means of `nfct':
nfct helper add ftp inet tcp
[ It must be a valid existing helper supported by conntrack-tools ]
2) Add rules to enable the FTP user-space helper which is
used to track traffic going to TCP port 21.
For locally generated packets:
iptables -I OUTPUT -t raw -p tcp --dport 21 -j CT --helper ftp
For non-locally generated packets:
iptables -I PREROUTING -t raw -p tcp --dport 21 -j CT --helper ftp
3) Run the test conntrackd in helper mode (see example files under
doc/helper/conntrackd.conf
conntrackd
4) Generate FTP traffic going, if everything is OK, then conntrackd
should create expectations (you can check that with `conntrack':
conntrack -E expect
[NEW] 301 proto=6 src=192.168.1.136 dst=130.89.148.12 sport=0 dport=54037 mask-src=255.255.255.255 mask-dst=255.255.255.255 sport=0 dport=65535 master-src=192.168.1.136 master-dst=130.89.148.12 sport=57127 dport=21 class=0 helper=ftp
[DESTROY] 301 proto=6 src=192.168.1.136 dst=130.89.148.12 sport=0 dport=54037 mask-src=255.255.255.255 mask-dst=255.255.255.255 sport=0 dport=65535 master-src=192.168.1.136 master-dst=130.89.148.12 sport=57127 dport=21 class=0 helper=ftp
This confirms that our test helper is receiving packets including the
conntrack information, and adding expectations in kernel-space.
The user-space helper can also store its private tracking information
in the conntrack structure in the kernel via the CTA_HELP_INFO. The
kernel will consider this a binary blob whose layout is unknown. This
information will be included in the information that is transfered
to user-space via glue code that integrates nfnetlink_queue and
ctnetlink.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch uses the new variable length conntrack extensions.
Instead of using union nf_conntrack_help that contain all the
helper private data information, we allocate variable length
area to store the private helper data.
This patch includes the modification of all existing helpers.
It also includes a couple of include header to avoid compilation
warnings.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Explicit helper attachment via the CT target is broken with NAT
if non-standard ports are used. This problem was hidden behind
the automatic helper assignment routine. Thus, it becomes more
noticeable now that we can disable the automatic helper assignment
with Eric Leblond's:
9e8ac5a netfilter: nf_ct_helper: allow to disable automatic helper assignment
Basically, nf_conntrack_alter_reply asks for looking up the helper
up if NAT is enabled. Unfortunately, we don't have the conntrack
template at that point anymore.
Since we don't want to rely on the automatic helper assignment,
we can skip the second look-up and stick to the helper that was
attached by iptables. With the CT target, the user is in full
control of helper attachment, thus, the policy is to trust what
the user explicitly configures via iptables (no automatic magic
anymore).
Interestingly, this bug was hidden by the automatic helper look-up
code. But it can be easily trigger if you attach the helper in
a non-standard port, eg.
iptables -I PREROUTING -t raw -p tcp --dport 8888 \
-j CT --helper ftp
And you disabled the automatic helper assignment.
I added the IPS_HELPER_BIT that allows us to differenciate between
a helper that has been explicitly attached and those that have been
automatically assigned. I didn't come up with a better solution
(having backward compatibility in mind).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch allows you to disable automatic conntrack helper
lookup based on TCP/UDP ports, eg.
echo 0 > /proc/sys/net/netfilter/nf_conntrack_helper
[ Note: flows that already got a helper will keep using it even
if automatic helper assignment has been disabled ]
Once this behaviour has been disabled, you have to explicitly
use the iptables CT target to attach helper to flows.
There are good reasons to stop supporting automatic helper
assignment, for further information, please read:
http://www.netfilter.org/news.html#2012-04-03
This patch also adds one message to inform that automatic helper
assignment is deprecated and it will be removed soon (this is
spotted only once, with the first flow that gets a helper attached
to make it as less annoying as possible).
Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch allows you to set expectfn which is specifically used
by the NAT side of most of the existing conntrack helpers.
I have added a symbol map that uses a string as key to look up for
the function that is attached to the expectation object. This is
the best solution I came out with to solve this issue.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch partially reverts:
3d058d7 netfilter: rework user-space expectation helper support
that was applied during the 3.2 development cycle.
After this patch, the tree remains just like before patch bc01bef,
that initially added the preliminary infrastructure.
I decided to partially revert this patch because the approach
that I proposed to resolve this problem is broken in NAT setups.
Moreover, a new infrastructure will be submitted for the 3.3.x
development cycle that resolve the existing issues while
providing a neat solution.
Since nobody has been seriously using this infrastructure in
user-space, the removal of this feature should affect any know
FOSS project (to my knowledge).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).
We miss needed barriers, even on x86, when y is not NULL.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This partially reworks bc01befdcf
which added userspace expectation support.
This patch removes the nf_ct_userspace_expect_list since now we
force to use the new iptables CT target feature to add the helper
extension for conntracks that have attached expectations from
userspace.
A new version of the proof-of-concept code to implement userspace
helpers from userspace is available at:
http://people.netfilter.org/pablo/userspace-conntrack-helpers/nf-ftp-helper-POC.tar.bz2
This patch also modifies the CT target to allow to set the
conntrack's userspace helper status flags. This flag is used
to tell the conntrack system to explicitly allocate the helper
extension.
This helper extension is useful to link the userspace expectations
with the master conntrack that is being tracked from one userspace
helper.
This feature fixes a problem in the current approach of the
userspace helper support. Basically, if the master conntrack that
has got a userspace expectation vanishes, the expectations point to
one invalid memory address. Thus, triggering an oops in the
expectation deletion event path.
I decided not to add a new revision of the CT target because
I only needed to add a new flag for it. I'll document in this
issue in the iptables manpage. I have also changed the return
value from EINVAL to EOPNOTSUPP if one flag not supported is
specified. Thus, in the future adding new features that only
require a new flag can be added without a new revision.
There is no official code using this in userspace (apart from
the proof-of-concept) that uses this infrastructure but there
will be some by beginning 2012.
Reported-by: Sam Roberts <vieuxtech@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.
Convert all rcu_assign_pointer of NULL value.
//smpl
@@ expression P; @@
- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)
// </smpl>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use is_vmalloc_addr() in nf_ct_free_hashtable() and get rid of
the vmalloc flags to indicate that a hash table has been allocated
using vmalloc().
Signed-off-by: Patrick McHardy <kaber@trash.net>
Use RCU helpers to reduce number of sparse warnings
(CONFIG_SPARSE_RCU_POINTER=y), and adds lockdep checks.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
As noticed by Jon Masters <jonathan@jonmasters.org>, the conntrack hash
size is global and not per namespace, but modifiable at runtime through
/sys/module/nf_conntrack/hashsize. Changing the hash size will only
resize the hash in the current namespace however, so other namespaces
will use an invalid hash size. This can cause crashes when enlarging
the hashsize, or false negative lookups when shrinking it.
Move the hash size into the per-namespace data and only use the global
hash size to initialize the per-namespace value when instanciating a
new namespace. Additionally restrict hash resizing to init_net for
now as other namespaces are not handled currently.
Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new target for the raw table, which can be used to specify conntrack
parameters for specific connections, f.i. the conntrack helper.
The target attaches a "template" connection tracking entry to the skb, which
is used by the conntrack core when initializing a new conntrack.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Support initializing selected parameters of new conntrack entries from a
"conntrack template", which is a specially marked conntrack entry attached
to the skb.
Currently the helper and the event delivery masks can be initialized this
way.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Make sure not to assign a helper for a different network or transport
layer protocol to a connection.
Additionally change expectation deletion by helper to compare the name
directly - there might be multiple helper registrations using the same
name, currently one of them is chosen in an unpredictable manner and
only those expectations are removed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch moves the helper destruction to a function that lives
in nf_conntrack_helper.c. This new function is used in the patch
to add ctnetlink reliable event delivery.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Commit ea781f197d (netfilter: nf_conntrack: use SLAB_DESTROY_BY_RCU and)
get rid of call_rcu() was missing one conversion to the hlist_nulls
functions, causing a crash when unloading conntrack helper modules.
Reported-and-tested-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Use "hlist_nulls" infrastructure we added in 2.6.29 for RCUification of UDP & TCP.
This permits an easy conversion from call_rcu() based hash lists to a
SLAB_DESTROY_BY_RCU one.
Avoiding call_rcu() delay at nf_conn freeing time has numerous gains.
First, it doesnt fill RCU queues (up to 10000 elements per cpu).
This reduces OOM possibility, if queued elements are not taken into account
This reduces latency problems when RCU queue size hits hilimit and triggers
emergency mode.
- It allows fast reuse of just freed elements, permitting better use of
CPU cache.
- We delete rcu_head from "struct nf_conn", shrinking size of this structure
by 8 or 16 bytes.
This patch only takes care of "struct nf_conn".
call_rcu() is still used for less critical conntrack parts, that may
be converted later if necessary.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Jiri Kosina