When a slab cache uses SLAB_DESTROY_BY_RCU, we must be careful when allocating
objects, since slab allocator could give a freed object still used by lockless
readers.
In particular, nf_conntrack RCU lookups rely on ct->tuplehash[xxx].hnnode.next
being always valid (ie containing a valid 'nulls' value, or a valid pointer to next
object in hash chain.)
kmem_cache_zalloc() setups object with NULL values, but a NULL value is not valid
for ct->tuplehash[xxx].hnnode.next.
Fix is to call kmem_cache_alloc() and do the zeroing ourself.
As spotted by Patrick, we also need to make sure lookup keys are committed to
memory before setting refcount to 1, or a lockless reader could get a reference
on the old version of the object. Its key re-check could then pass the barrier.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
As reported by Philip, the UNTRACKED state bit does not fit within
the 8-bit state_mask member. Enlarge state_mask and give status_mask
a few more bits too.
Reported-by: Philip Craig <philipc@snapgear.com>
References: http://markmail.org/thread/b7eg6aovfh4agyz7
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
When NAT helpers change the TCP packet size, the highest seen sequence
number needs to be corrected. This is currently only done upwards, when
the packet size is reduced the sequence number is unchanged. This causes
TCP conntrack to falsely detect unacknowledged data and decrease the
timeout.
Fix by updating the highest seen sequence number in both directions after
packet mangling.
Tested-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
RCU barriers, rcu_barrier(), is inserted two places.
In nf_conntrack_expect.c nf_conntrack_expect_fini() before the
kmem_cache_destroy(). Firstly to make sure the callback to the
nf_ct_expect_free_rcu() code is still around. Secondly because I'm
unsure about the consequence of having in flight
nf_ct_expect_free_rcu/kmem_cache_free() calls while doing a
kmem_cache_destroy() slab destroy.
And in nf_conntrack_extend.c nf_ct_extend_unregister(), inorder to
wait for completion of callbacks to __nf_ct_ext_free_rcu(), which is
invoked by __nf_ct_ext_add(). It might be more efficient to call
rcu_barrier() in nf_conntrack_core.c nf_conntrack_cleanup_net(), but
thats make it more difficult to read the code (as the callback code
in located in nf_conntrack_extend.c).
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>
As noticed by Török Edwin <edwintorok@gmail.com>:
Compiling the kernel with clang has shown this warning:
net/netfilter/xt_rateest.c:69:16: warning: self-comparison always results in a
constant value
ret &= pps2 == pps2;
^
Looking at the code:
if (info->flags & XT_RATEEST_MATCH_BPS)
ret &= bps1 == bps2;
if (info->flags & XT_RATEEST_MATCH_PPS)
ret &= pps2 == pps2;
Judging from the MATCH_BPS case it seems to be a typo, with the intention of
comparing pps1 with pps2.
http://bugzilla.kernel.org/show_bug.cgi?id=13535
Signed-off-by: Patrick McHardy <kaber@trash.net>
Commit v2.6.29-rc5-872-gacc738f ("xtables: avoid pointer to self")
forgot to copy the initial quota value supplied by iptables into the
private structure, thus counting from whatever was in the memory
kmalloc returned.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
net/netfilter/xt_NFQUEUE.c:46:9: warning: incorrect type in assignment (different base types)
net/netfilter/xt_NFQUEUE.c:46:9: expected unsigned int [unsigned] [usertype] ipaddr
net/netfilter/xt_NFQUEUE.c:46:9: got restricted unsigned int
net/netfilter/xt_NFQUEUE.c:68:10: warning: incorrect type in assignment (different base types)
net/netfilter/xt_NFQUEUE.c:68:10: expected unsigned int [unsigned] <noident>
net/netfilter/xt_NFQUEUE.c:68:10: got restricted unsigned int
net/netfilter/xt_NFQUEUE.c:69:10: warning: incorrect type in assignment (different base types)
net/netfilter/xt_NFQUEUE.c:69:10: expected unsigned int [unsigned] <noident>
net/netfilter/xt_NFQUEUE.c:69:10: got restricted unsigned int
net/netfilter/xt_NFQUEUE.c:70:10: warning: incorrect type in assignment (different base types)
net/netfilter/xt_NFQUEUE.c:70:10: expected unsigned int [unsigned] <noident>
net/netfilter/xt_NFQUEUE.c:70:10: got restricted unsigned int
net/netfilter/xt_NFQUEUE.c:71:10: warning: incorrect type in assignment (different base types)
net/netfilter/xt_NFQUEUE.c:71:10: expected unsigned int [unsigned] <noident>
net/netfilter/xt_NFQUEUE.c:71:10: got restricted unsigned int
net/netfilter/xt_cluster.c:20:55: warning: incorrect type in return expression (different base types)
net/netfilter/xt_cluster.c:20:55: expected unsigned int
net/netfilter/xt_cluster.c:20:55: got restricted unsigned int const [usertype] ip
net/netfilter/xt_cluster.c:20:55: warning: incorrect type in return expression (different base types)
net/netfilter/xt_cluster.c:20:55: expected unsigned int
net/netfilter/xt_cluster.c:20:55: got restricted unsigned int const [usertype] ip
Signed-off-by: Patrick McHardy <kaber@trash.net>
The RCU protected conntrack hash lookup only checks whether the entry
has a refcount of zero to decide whether it is stale. This is not
sufficient, entries are explicitly removed while there is at least
one reference left, possibly more. Explicitly check whether the entry
has been marked as dying to fix this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
New connection tracking entries are inserted into the hash before they
are fully set up, namely the CONFIRMED bit is not set and the timer not
started yet. This can theoretically lead to a race with timer, which
would set the timeout value to a relative value, most likely already in
the past.
Perform hash insertion as the final step to fix this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
death_by_timeout() might delete a conntrack from hash list
and insert it in dying list.
nf_ct_delete_from_lists(ct);
nf_ct_insert_dying_list(ct);
I believe a (lockless) reader could *catch* ct while doing a lookup
and miss the end of its chain.
(nulls lookup algo must check the null value at the end of lookup and
should restart if the null value is not the expected one.
cf Documentation/RCU/rculist_nulls.txt for details)
We need to change nf_conntrack_init_net() and use a different "null" value,
guaranteed not being used in regular lists. Choose very large values, since
hash table uses [0..size-1] null values.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch improves ctnetlink event reliability if one broadcast
listener has set the NETLINK_BROADCAST_ERROR socket option.
The logic is the following: if an event delivery fails, we keep
the undelivered events in the missed event cache. Once the next
packet arrives, we add the new events (if any) to the missed
events in the cache and we try a new delivery, and so on. Thus,
if ctnetlink fails to deliver an event, we try to deliver them
once we see a new packet. Therefore, we may lose state
transitions but the userspace process gets in sync at some point.
At worst case, if no events were delivered to userspace, we make
sure that destroy events are successfully delivered. Basically,
if ctnetlink fails to deliver the destroy event, we remove the
conntrack entry from the hashes and we insert them in the dying
list, which contains inactive entries. Then, the conntrack timer
is added with an extra grace timeout of random32() % 15 seconds
to trigger the event again (this grace timeout is tunable via
/proc). The use of a limited random timeout value allows
distributing the "destroy" resends, thus, avoiding accumulating
lots "destroy" events at the same time. Event delivery may
re-order but we can identify them by means of the tuple plus
the conntrack ID.
The maximum number of conntrack entries (active or inactive) is
still handled by nf_conntrack_max. Thus, we may start dropping
packets at some point if we accumulate a lot of inactive conntrack
entries that did not successfully report the destroy event to
userspace.
During my stress tests consisting of setting a very small buffer
of 2048 bytes for conntrackd and the NETLINK_BROADCAST_ERROR socket
flag, and generating lots of very small connections, I noticed
very few destroy entries on the fly waiting to be resend.
A simple way to test this patch consist of creating a lot of
entries, set a very small Netlink buffer in conntrackd (+ a patch
which is not in the git tree to set the BROADCAST_ERROR flag)
and invoke `conntrack -F'.
For expectations, no changes are introduced in this patch.
Currently, event delivery is only done for new expectations (no
events from expectation expiration, removal and confirmation).
In that case, they need a per-expectation event cache to implement
the same idea that is exposed in this patch.
This patch can be useful to provide reliable flow-accouting. We
still have to add a new conntrack extension to store the creation
and destroy time.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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>
This patch reworks the per-cpu event caching to use the conntrack
extension infrastructure.
The main drawback is that we consume more memory per conntrack
if event delivery is enabled. This patch is required by the
reliable event delivery that follows to this patch.
BTW, this patch allows you to enable/disable event delivery via
/proc/sys/net/netfilter/nf_conntrack_events in runtime, although
you can still disable event caching as compilation option.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Use mod_timer_pending() instead of atomic sequence of del_timer()/
add_timer(). mod_timer_pending() does not rearm an inactive timer,
so we don't need the conntrack lock anymore to make sure we don't
accidentally rearm a timer of a conntrack which is in the process
of being destroyed.
With this change, we don't need to take the global lock anymore at all,
counter updates can be performed under the per-conntrack lock.
Signed-off-by: Patrick McHardy <kaber@trash.net>
.ko is normally not included in Kconfig help, make it consistent.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Introduce per-conntrack locks and use them instead of the global protocol
locks to avoid contention. Especially tcp_lock shows up very high in
profiles on larger machines.
This will also allow to simplify the upcoming reliable event delivery patches.
Signed-off-by: Patrick McHardy <kaber@trash.net>
This module uses rcu_call() thus it should use rcu_barrier() on module unload.
Also fixed a trivial typo 'nfetlink' -> 'nfnetlink' in comment.
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the XT_SOCKET_TRANSPARENT flag is set, enabled 'transparent'
socket option is required for the socket to be matched.
Signed-off-by: Laszlo Attila Toth <panther@balabit.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Passive OS fingerprinting netfilter module allows to passively detect
remote OS and perform various netfilter actions based on that knowledge.
This module compares some data (WS, MSS, options and it's order, ttl, df
and others) from packets with SYN bit set with dynamically loaded OS
fingerprints.
Fingerprint matching rules can be downloaded from OpenBSD source tree
or found in archive and loaded via netfilter netlink subsystem into
the kernel via special util found in archive.
Archive contains library file (also attached), which was shipped
with iptables extensions some time ago (at least when ipt_osf existed
in patch-o-matic).
Following changes were made in this release:
* added NLM_F_CREATE/NLM_F_EXCL checks
* dropped _rcu list traversing helpers in the protected add/remove calls
* dropped unneded structures, debug prints, obscure comment and check
Fingerprints can be downloaded from
http://www.openbsd.org/cgi-bin/cvsweb/src/etc/pf.os
or can be found in archive
Example usage:
-d switch removes fingerprints
Please consider for inclusion.
Thank you.
Passive OS fingerprint homepage (archives, examples):
http://www.ioremap.net/projects/osf
Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Adds support for specifying a range of queues instead of a single queue
id. Flows will be distributed across the given range.
This is useful for multicore systems: Instead of having a single
application read packets from a queue, start multiple
instances on queues x, x+1, .. x+n. Each instance can process
flows independently.
Packets for the same connection are put into the same queue.
Signed-off-by: Holger Eitzenberger <heitzenberger@astaro.com>
Signed-off-by: Florian Westphal <fwestphal@astaro.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
We can use wildcard matching here, just like
ab4f21e6fb ("xtables: use NFPROTO_UNSPEC
in more extensions").
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Define three accessors to get/set dst attached to a skb
struct dst_entry *skb_dst(const struct sk_buff *skb)
void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;
Delete skb->dst field
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define skb_rtable(const struct sk_buff *skb) accessor to get rtable from skb
Delete skb->rtable field
Setting rtable is not allowed, just set dst instead as rtable is an alias.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes the notify chain infrastructure and replace it
by a simple function pointer. This issue has been mentioned in the
mailing list several times: the use of the notify chain adds
too much overhead for something that is only used by ctnetlink.
This patch also changes nfnetlink_send(). It seems that gfp_any()
returns GFP_KERNEL for user-context request, like those via
ctnetlink, inside the RCU read-side section which is not valid.
Using GFP_KERNEL is also evil since netlink may schedule(),
this leads to "scheduling while atomic" bug reports.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch simplifies the conntrack event caching system by removing
several events:
* IPCT_[*]_VOLATILE, IPCT_HELPINFO and IPCT_NATINFO has been deleted
since the have no clients.
* IPCT_COUNTER_FILLING which is a leftover of the 32-bits counter
days.
* IPCT_REFRESH which is not of any use since we always include the
timeout in the messages.
After this patch, the existing events are:
* IPCT_NEW, IPCT_RELATED and IPCT_DESTROY, that are used to identify
addition and deletion of entries.
* IPCT_STATUS, that notes that the status bits have changes,
eg. IPS_SEEN_REPLY and IPS_ASSURED.
* IPCT_PROTOINFO, that reports that internal protocol information has
changed, eg. the TCP, DCCP and SCTP protocol state.
* IPCT_HELPER, that a helper has been assigned or unassigned to this
entry.
* IPCT_MARK and IPCT_SECMARK, that reports that the mark has changed, this
covers the case when a mark is set to zero.
* IPCT_NATSEQADJ, to report that there's updates in the NAT sequence
adjustment.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
During the module removal there are no possible event listeners
since ctnetlink must be removed before to allow removing
nf_conntrack. This patch removes the event reporting for the
module removal case which is not of any use in the existing code.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch cleans up the message calculation to make it similar
to rtnetlink, moreover, it removes unneeded verbose information.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch is a cleanup, it removes the `nowait' parameter
from all *fill_info() function since it is always set to one.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch cleans up the message handling path in two aspects:
* it uses NLMSG_LENGTH() instead of NLMSG_SPACE() like rtnetlink
does in this case to check if there is enough room for the
Netlink/nfnetlink headers. No need to check for the padding room.
* it removes a redundant header size checking that has been
already do at the beginning of the function.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The patch below adds supporting TCP simultaneous open to conntrack. The
unused LISTEN state is replaced by a new state (SYN_SENT2) denoting the
second SYN sent from the reply direction in the new case. The state table
is updated and the function tcp_in_window is modified to handle
simultaneous open.
The functionality can fairly easily be tested by socat. A sample tcpdump
recording
23:21:34.244733 IP (tos 0x0, ttl 64, id 49224, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.254.2020 > 192.168.0.1.2020: S, cksum 0xe75f (correct), 3383710133:3383710133(0) win 5840 <mss 1460,sackOK,timestamp 173445629 0,nop,wscale 7>
23:21:34.244783 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.0.1.2020 > 192.168.0.254.2020: R, cksum 0x0253 (correct), 0:0(0) ack 3383710134 win 0
23:21:36.038680 IP (tos 0x0, ttl 64, id 28092, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.1.2020 > 192.168.0.254.2020: S, cksum 0x704b (correct), 2634546729:2634546729(0) win 5840 <mss 1460,sackOK,timestamp 824213 0,nop,wscale 1>
23:21:36.038777 IP (tos 0x0, ttl 64, id 49225, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.254.2020 > 192.168.0.1.2020: S, cksum 0xb179 (correct), 3383710133:3383710133(0) ack 2634546730 win 5840 <mss 1460,sackOK,timestamp 173447423 824213,nop,wscale 7>
23:21:36.038847 IP (tos 0x0, ttl 64, id 28093, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.1.2020 > 192.168.0.254.2020: ., cksum 0xebad (correct), ack 3383710134 win 2920 <nop,nop,timestamp 824213 173447423>
and the corresponding netlink events:
[NEW] tcp 6 120 SYN_SENT src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 [UNREPLIED] src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020
[UPDATE] tcp 6 120 LISTEN src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020
[UPDATE] tcp 6 60 SYN_RECV src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020
[UPDATE] tcp 6 432000 ESTABLISHED src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020 [ASSURED]
The RST packet was dropped in the raw table, thus it did not reach
conntrack. nfnetlink_conntrack is unpatched so it shows the new SYN_SENT2
state as the old unused LISTEN.
With TCP simultaneous open support we satisfy REQ-2 in RFC 5382 ;-) .
Additional minor correction in this patch is that in order to catch
uninitialized reply directions, "td_maxwin == 0" is used instead of
"td_end == 0" because the former can't be true except in uninitialized
state while td_end may accidentally be equal to zero in the mid of a
connection.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch adds CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ that exposes
the u64 handshake sequence number to user-space.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This problem was introduced in 72961ecf84
since no space was reserved for the new attributes NFULA_HWTYPE,
NFULA_HWLEN and NFULA_HWHEADER.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
The function dl_seq_show() returns 1 (equal to SEQ_SKIP) in case
a seq_printf() call return -1. It should return -1.
This SEQ_SKIP behavior brakes processing the proc file e.g. via a
pipe or just through less.
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Robert L Mathews discovered that some clients send evil TCP RST segments,
which are accepted by netfilter conntrack but discarded by the
destination. Thus the conntrack entry is destroyed but the destination
retransmits data until timeout.
The same technique, i.e. sending properly crafted RST segments, can easily
be used to bypass connlimit/connbytes based restrictions (the sample
script written by Robert can be found in the netfilter mailing list
archives).
The patch below adds a new flag and new field to struct ip_ct_tcp_state so
that checking RST segments can be made more strict and thus TCP conntrack
can catch the invalid ones: the RST segment is accepted only if its
sequence number higher than or equal to the highest ack we seen from the
other direction. (The last_ack field cannot be reused because it is used
to catch resent packets.)
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Use genl_register_family_with_ops() instead of a copy.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes the use of fwmarks to denote IPv4 virtual services
which was unfortunately broken as a result of the integration
of IPv6 support into IPVS, which was included in 2.6.28.
The problem arises because fwmarks are stored in the 4th octet
of a union nf_inet_addr .all, however in the case of IPv4 only
the first octet, corresponding to .ip, is assigned and compared.
In other words, using .all = { 0, 0, 0, htonl(svc->fwmark) always
results in a value of 0 (32bits) being stored for IPv4. This means
that one fwmark can be used, as it ends up being mapped to 0, but things
break down when multiple fwmarks are used, as they all end up being mapped
to 0.
As fwmarks are 32bits a reasonable fix seems to be to just store the fwmark
in .ip, and comparing and storing .ip when fwmarks are used.
This patch makes the assumption that in calls to ip_vs_ct_in_get()
and ip_vs_sched_persist() if the proto parameter is IPPROTO_IP then
we are dealing with an fwmark. I believe this is valid as ip_vs_in()
does fairly strict filtering on the protocol and IPPROTO_IP should
not be used in these calls unless explicitly passed when making
these calls for fwmarks in ip_vs_sched_persist().
Tested-by: Fabien Duchêne <fabien.duchene@student.uclouvain.be>
Cc: Joseph Mack NA3T <jmack@wm7d.net>
Cc: Julius Volz <julius.volz@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
