This patch removes CONFIG_NETFILTER_DEBUG and _ASSERT() macros as they
are no longer required. Replace _ASSERT() macros with WARN_ON().
Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This also removes __nf_ct_unconfirmed_destroy() call from
nf_ct_iterate_cleanup_net, so that function can be used only
when missing conntracks from unconfirmed list isn't a problem.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
sledgehammer to be used on module unload (to remove affected conntracks
from all namespaces).
It will also flag all unconfirmed conntracks as dying, i.e. they will
not be committed to main table.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
There are several places where we needlesly call nf_ct_iterate_cleanup,
we should instead iterate the full table at module unload time.
This is a leftover from back when the conntrack table got duplicated
per net namespace.
So rename nf_ct_iterate_cleanup to nf_ct_iterate_cleanup_net.
A later patch will then add a non-net variant.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This function is now obsolete and always returns false.
This change has no effect on generated code.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
resurrect an old patch from Pablo Neira to remove the untracked objects.
Currently, there are four possible states of an skb wrt. conntrack.
1. No conntrack attached, ct is NULL.
2. Normal (kmem cache allocated) ct attached.
3. a template (kmalloc'd), not in any hash tables at any point in time
4. the 'untracked' conntrack, a percpu nf_conn object, tagged via
IPS_UNTRACKED_BIT in ct->status.
Untracked is supposed to be identical to case 1. It exists only
so users can check
-m conntrack --ctstate UNTRACKED vs.
-m conntrack --ctstate INVALID
e.g. attempts to set connmark on INVALID or UNTRACKED conntracks is
supposed to be a no-op.
Thus currently we need to check
ct == NULL || nf_ct_is_untracked(ct)
in a lot of places in order to avoid altering untracked objects.
The other consequence of the percpu untracked object is that all
-j NOTRACK (and, later, kfree_skb of such skbs) result in an atomic op
(inc/dec the untracked conntracks refcount).
This adds a new kernel-private ctinfo state, IP_CT_UNTRACKED, to
make the distinction instead.
The (few) places that care about packet invalid (ct is NULL) vs.
packet untracked now need to test ct == NULL vs. ctinfo == IP_CT_UNTRACKED,
but all other places can omit the nf_ct_is_untracked() check.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Since the nfct and nfctinfo have been combined, the nf_conn structure
must be at least 8 bytes aligned, as the 3 LSB bits are used for the
nfctinfo. But there's a fake nf_conn structure to denote untracked
connections, which is created by a PER_CPU construct. This does not
guarantee that it will be 8 bytes aligned and can break the logic in
determining the correct nfctinfo.
I triggered this on a 32bit machine with the following error:
BUG: unable to handle kernel NULL pointer dereference at 00000af4
IP: nf_ct_deliver_cached_events+0x1b/0xfb
*pdpt = 0000000031962001 *pde = 0000000000000000
Oops: 0000 [#1] SMP
[Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables ipv6 crc_ccitt ppdev r8169 parport_pc parport
OK ]
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-test+ #75
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
task: c126ec00 task.stack: c1258000
EIP: nf_ct_deliver_cached_events+0x1b/0xfb
EFLAGS: 00010202 CPU: 0
EAX: 0021cd01 EBX: 00000000 ECX: 27b0c767 EDX: 32bcb17a
ESI: f34135c0 EDI: f34135c0 EBP: f2debd60 ESP: f2debd3c
DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 80050033 CR2: 00000af4 CR3: 309a0440 CR4: 001406f0
Call Trace:
<SOFTIRQ>
? ipv6_skip_exthdr+0xac/0xcb
ipv6_confirm+0x10c/0x119 [nf_conntrack_ipv6]
nf_hook_slow+0x22/0xc7
nf_hook+0x9a/0xad [ipv6]
? ip6t_do_table+0x356/0x379 [ip6_tables]
? ip6_fragment+0x9e9/0x9e9 [ipv6]
ip6_output+0xee/0x107 [ipv6]
? ip6_fragment+0x9e9/0x9e9 [ipv6]
dst_output+0x36/0x4d [ipv6]
NF_HOOK.constprop.37+0xb2/0xba [ipv6]
? icmp6_dst_alloc+0x2c/0xfd [ipv6]
? local_bh_enable+0x14/0x14 [ipv6]
mld_sendpack+0x1c5/0x281 [ipv6]
? mark_held_locks+0x40/0x5c
mld_ifc_timer_expire+0x1f6/0x21e [ipv6]
call_timer_fn+0x135/0x283
? detach_if_pending+0x55/0x55
? mld_dad_timer_expire+0x3e/0x3e [ipv6]
__run_timers+0x111/0x14b
? mld_dad_timer_expire+0x3e/0x3e [ipv6]
run_timer_softirq+0x1c/0x36
__do_softirq+0x185/0x37c
? test_ti_thread_flag.constprop.19+0xd/0xd
do_softirq_own_stack+0x22/0x28
</SOFTIRQ>
irq_exit+0x5a/0xa4
smp_apic_timer_interrupt+0x2a/0x34
apic_timer_interrupt+0x37/0x3c
By using DEFINE/DECLARE_PER_CPU_ALIGNED we can enforce at least 8 byte
alignment as all cache line sizes are at least 8 bytes or more.
Fixes: a9e419dc7b ("netfilter: merge ctinfo into nfct pointer storage area")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After this change conntrack operations (lookup, creation, matching from
ruleset) only access one instead of two sk_buff cache lines.
This works for normal conntracks because those are allocated from a slab
that guarantees hw cacheline or 8byte alignment (whatever is larger)
so the 3 bits needed for ctinfo won't overlap with nf_conn addresses.
Template allocation now does manual address alignment (see previous change)
on arches that don't have sufficent kmalloc min alignment.
Some spots intentionally use skb->_nfct instead of skb_nfct() helpers,
this is to avoid undoing the skb_nfct() use when we remove untracked
conntrack object in the future.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The next change will merge skb->nfct pointer and skb->nfctinfo
status bits into single skb->_nfct (unsigned long) area.
For this to work nf_conn addresses must always be aligned at least on
an 8 byte boundary since we will need the lower 3bits to store nfctinfo.
Conntrack templates are allocated via kmalloc.
kbuild test robot reported
BUILD_BUG_ON failed: NFCT_INFOMASK >= ARCH_KMALLOC_MINALIGN
on v1 of this patchset, so not all platforms meet this requirement.
Do manual alignment if needed, the alignment offset is stored in the
nf_conn entry protocol area. This works because templates are not
handed off to L4 protocol trackers.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a helper to assign a nf_conn entry and the ctinfo bits to an sk_buff.
This avoids changing code in followup patch that merges skb->nfct and
skb->nfctinfo into skb->_nfct.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
currently aliased to try_module_get/_put.
Will be changed in next patch when we add functions to make use of ->net
argument to store usercount per l3proto tracker.
This is needed to avoid registering the conntrack hooks in all netns and
later only enable connection tracking in those that need conntrack.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stas Nichiporovich reports oops in nf_nat_bysource_cmp(), trying to
access nf_conn struct at address 0xffffffffffffff50.
This is the result of fetching a null rhash list (struct embedded at
offset 176; 0 - 176 gets us ...fff50).
The problem is that conntrack entries are allocated from a
SLAB_DESTROY_BY_RCU cache, i.e. entries can be free'd and reused
on another cpu while nf nat bysource hash access the same conntrack entry.
Freeing is fine (we hold rcu read lock); zeroing rhlist_head isn't.
-> Move the rhlist struct outside of the memset()-inited area.
Fixes: 7c96643519 ("netfilter: move nat hlist_head to nf_conn")
Reported-by: Stas Nichiporovich <stasn77@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
I got offlist bug report about failing connections and high cpu usage.
This happens because we hit 'elasticity' checks in rhashtable that
refuses bucket list exceeding 16 entries.
The nat bysrc hash unfortunately needs to insert distinct objects that
share same key and are identical (have same source tuple), this cannot
be avoided.
Switch to the rhlist interface which is designed for this.
The nulls_base is removed here, I don't think its needed:
A (unlikely) false positive results in unneeded port clash resolution,
a false negative results in packet drop during conntrack confirmation,
when we try to insert the duplicate into main conntrack hash table.
Tested by adding multiple ip addresses to host, then adding
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
... and then creating multiple connections, from same source port but
different addresses:
for i in $(seq 2000 2032);do nc -p 1234 192.168.7.1 $i > /dev/null & done
(all of these then get hashed to same bysource slot)
Then, to test that nat conflict resultion is working:
nc -s 10.0.0.1 -p 1234 192.168.7.1 2000
nc -s 10.0.0.2 -p 1234 192.168.7.1 2000
tcp .. src=10.0.0.1 dst=192.168.7.1 sport=1234 dport=2000 src=192.168.7.1 dst=192.168.7.10 sport=2000 dport=1024 [ASSURED]
tcp .. src=10.0.0.2 dst=192.168.7.1 sport=1234 dport=2000 src=192.168.7.1 dst=192.168.7.10 sport=2000 dport=1025 [ASSURED]
tcp .. src=192.168.7.10 dst=192.168.7.1 sport=1234 dport=2000 src=192.168.7.1 dst=192.168.7.10 sport=2000 dport=1234 [ASSURED]
tcp .. src=192.168.7.10 dst=192.168.7.1 sport=1234 dport=2001 src=192.168.7.1 dst=192.168.7.10 sport=2001 dport=1234 [ASSURED]
[..]
-> nat altered source ports to 1024 and 1025, respectively.
This can also be confirmed on destination host which shows
ESTAB 0 0 192.168.7.1:2000 192.168.7.10:1024
ESTAB 0 0 192.168.7.1:2000 192.168.7.10:1025
ESTAB 0 0 192.168.7.1:2000 192.168.7.10:1234
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Fixes: 870190a9ec ("netfilter: nat: convert nat bysrc hash to rhashtable")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After timer removal this just calls nf_ct_delete so remove the __ prefix
version and make nf_ct_kill a shorthand for nf_ct_delete.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
With stats enabled this eats 80 bytes on x86_64 per nf_conn entry, as
Eric Dumazet pointed out during netfilter workshop 2016.
Eric also says: "Another reason was the fact that Thomas was about to
change max timer range [..]" (500462a9de, 'timers: Switch to
a non-cascading wheel').
Remove the timer and use a 32bit jiffies value containing timestamp until
entry is valid.
During conntrack lookup, even before doing tuple comparision, check
the timeout value and evict the entry in case it is too old.
The dying bit is used as a synchronization point to avoid races where
multiple cpus try to evict the same entry.
Because lookup is always lockless, we need to bump the refcnt once
when we evict, else we could try to evict already-dead entry that
is being recycled.
This is the standard/expected way when conntrack entries are destroyed.
Followup patches will introduce garbage colliction via work queue
and further places where we can reap obsoleted entries (e.g. during
netlink dumps), this is needed to avoid expired conntracks from hanging
around for too long when lookup rate is low after a busy period.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Since commit 64b87639c9 ("netfilter: conntrack: fix race between
nf_conntrack proc read and hash resize") introduce the
nf_conntrack_get_ht, so there's no need to check nf_conntrack_generation
again and again to get the hash table and hash size. And convert
nf_conntrack_get_ht to inline function here.
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter/IPVS updates for net-next
The following patchset contains Netfilter/IPVS updates for net-next,
they are:
1) Count pre-established connections as active in "least connection"
schedulers such that pre-established connections to avoid overloading
backend servers on peak demands, from Michal Kubecek via Simon Horman.
2) Address a race condition when resizing the conntrack table by caching
the bucket size when fulling iterating over the hashtable in these
three possible scenarios: 1) dump via /proc/net/nf_conntrack,
2) unlinking userspace helper and 3) unlinking custom conntrack timeout.
From Liping Zhang.
3) Revisit early_drop() path to perform lockless traversal on conntrack
eviction under stress, use del_timer() as synchronization point to
avoid two CPUs evicting the same entry, from Florian Westphal.
4) Move NAT hlist_head to nf_conn object, this simplifies the existing
NAT extension and it doesn't increase size since recent patches to
align nf_conn, from Florian.
5) Use rhashtable for the by-source NAT hashtable, also from Florian.
6) Don't allow --physdev-is-out from OUTPUT chain, just like
--physdev-out is not either, from Hangbin Liu.
7) Automagically set on nf_conntrack counters if the user tries to
match ct bytes/packets from nftables, from Liping Zhang.
8) Remove possible_net_t fields in nf_tables set objects since we just
simply pass the net pointer to the backend set type implementations.
9) Fix possible off-by-one in h323, from Toby DiPasquale.
10) early_drop() may be called from ctnetlink patch, so we must hold
rcu read size lock from them too, this amends Florian's patch #3
coming in this batch, from Liping Zhang.
11) Use binary search to validate jump offset in x_tables, this
addresses the O(n!) validation that was introduced recently
resolve security issues with unpriviledge namespaces, from Florian.
12) Fix reference leak to connlabel in error path of nft_ct, from Zhang.
13) Three updates for nft_log: Fix log prefix leak in error path. Bail
out on loglevel larger than debug in nft_log and set on the new
NF_LOG_F_COPY_LEN flag when snaplen is specified. Again from Zhang.
14) Allow to filter rule dumps in nf_tables based on table and chain
names.
15) Simplify connlabel to always use 128 bits to store labels and
get rid of unused function in xt_connlabel, from Florian.
16) Replace set_expect_timeout() by mod_timer() from the h323 conntrack
helper, by Gao Feng.
17) Put back x_tables module reference in nft_compat on error, from
Liping Zhang.
18) Add a reference count to the x_tables extensions cache in
nft_compat, so we can remove them when unused and avoid a crash
if the extensions are rmmod, again from Zhang.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
It did use a fixed-size bucket list plus single lock to protect add/del.
Unlike the main conntrack table we only need to add and remove keys.
Convert it to rhashtable to get table autosizing and per-bucket locking.
The maximum number of entries is -- as before -- tied to the number of
conntracks so we do not need another upperlimit.
The change does not handle rhashtable_remove_fast error, only possible
"error" is -ENOENT, and that is something that can happen legitimetely,
e.g. because nat module was inserted at a later time and no src manip
took place yet.
Tested with http-client-benchmark + httpterm with DNAT and SNAT rules
in place.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The nat extension structure is 32bytes in size on x86_64:
struct nf_conn_nat {
struct hlist_node bysource; /* 0 16 */
struct nf_conn * ct; /* 16 8 */
union nf_conntrack_nat_help help; /* 24 4 */
int masq_index; /* 28 4 */
/* size: 32, cachelines: 1, members: 4 */
/* last cacheline: 32 bytes */
};
The hlist is needed to quickly check for possible tuple collisions
when installing a new nat binding. Storing this in the extension
area has two drawbacks:
1. We need ct backpointer to get the conntrack struct from the extension.
2. When reallocation of extension area occurs we need to fixup the bysource
hash head via hlist_replace_rcu.
We can avoid both by placing the hlist_head in nf_conn and place nf_conn in
the bysource hash rather than the extenstion.
We can also remove the ->move support; no other extension needs it.
Moving the entire nat extension into nf_conn would be possible as well but
then we have to add yet another callback for deletion from the bysource
hash table rather than just using nat extension ->destroy hook for this.
nf_conn size doesn't increase due to aligment, followup patch replaces
hlist_node with single pointer.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We don't need to acquire the bucket lock during early drop, we can
use lockless traveral just like ____nf_conntrack_find.
The timer deletion serves as synchronization point, if another cpu
attempts to evict same entry, only one will succeed with timer deletion.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We need to compute timeout.expires - jiffies, not the other way around.
Add a helper, another patch can then later change more places in
conntrack code where we currently open-code this.
Will allow us to only change one place later when we remove per-ct timer.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
No need to restrict this to module parameter.
We export a copy of the real hash size -- when user alters the value we
allocate the new table, copy entries etc before we update the real size
to the requested one.
This is also needed because the real size is used by concurrent readers
and cannot be changed without synchronizing the conntrack generation
seqcnt.
We only allow changing this value from the initial net namespace.
Tested using http-client-benchmark vs. httpterm with concurrent
while true;do
echo $RANDOM > /proc/sys/net/netfilter/nf_conntrack_buckets
done
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Curently we store zone information as a conntrack extension.
This has one drawback: for every lookup we need to fetch the zone data
from the extension area.
This change place the zone data directly into the main conntrack object
structure and then removes the zone conntrack extension.
The zone data is just 4 bytes, it fits into a padding hole before
the tuplehash info, so we do not even increase the nf_conn structure size.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
As earlier commit removed accessed to the hash from other files we can
also make it static.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
As gre does not have the srckey in the packet gre_pkt_to_tuple
needs to perform a lookup in it's per network namespace tables.
Pass in the proper network namespace to all pkt_to_tuple
implementations to ensure gre (and any similar protocols) can get this
right.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
include/net/netfilter/nf_conntrack.h
The conflict was an overlap between changing the type of the zone
argument to nf_ct_tmpl_alloc() whilst exporting nf_ct_tmpl_free.
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for net, they are:
1) Oneliner to restore maps in nf_tables since we support addressing registers
at 32 bits level.
2) Restore previous default behaviour in bridge netfilter when CONFIG_IPV6=n,
oneliner from Bernhard Thaler.
3) Out of bound access in ipset hash:net* set types, reported by Dave Jones'
KASan utility, patch from Jozsef Kadlecsik.
4) Fix ipset compilation with gcc 4.4.7 related to C99 initialization of
unnamed unions, patch from Elad Raz.
5) Add a workaround to address inconsistent endianess in the res_id field of
nfnetlink batch messages, reported by Florian Westphal.
6) Fix error paths of CT/synproxy since the conntrack template was moved to use
kmalloc, patch from Daniel Borkmann.
All of them look good to me to reach 4.2, I can route this to -stable myself
too, just let me know what you prefer.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 0838aa7fcf ("netfilter: fix netns dependencies with conntrack
templates") migrated templates to the new allocator api, but forgot to
update error paths for them in CT and synproxy to use nf_ct_tmpl_free()
instead of nf_conntrack_free().
Due to that, memory is being freed into the wrong kmemcache, but also
we drop the per net reference count of ct objects causing an imbalance.
In Brad's case, this leads to a wrap-around of net->ct.count and thus
lets __nf_conntrack_alloc() refuse to create a new ct object:
[ 10.340913] xt_addrtype: ipv6 does not support BROADCAST matching
[ 10.810168] nf_conntrack: table full, dropping packet
[ 11.917416] r8169 0000:07:00.0 eth0: link up
[ 11.917438] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 12.815902] nf_conntrack: table full, dropping packet
[ 15.688561] nf_conntrack: table full, dropping packet
[ 15.689365] nf_conntrack: table full, dropping packet
[ 15.690169] nf_conntrack: table full, dropping packet
[ 15.690967] nf_conntrack: table full, dropping packet
[...]
With slab debugging, it also reports the wrong kmemcache (kmalloc-512 vs.
nf_conntrack_ffffffff81ce75c0) and reports poison overwrites, etc. Thus,
to fix the problem, export and use nf_ct_tmpl_free() instead.
Fixes: 0838aa7fcf ("netfilter: fix netns dependencies with conntrack templates")
Reported-by: Brad Jackson <bjackson0971@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch replaces the zone id which is pushed down into functions
with the actual zone object. It's a bigger one-time change, but
needed for later on extending zones with a direction parameter, and
thus decoupling this additional information from all call-sites.
No functional changes in this patch.
The default zone becomes a global const object, namely nf_ct_zone_dflt
and will be returned directly in various cases, one being, when there's
f.e. no zoning support.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Quoting Daniel Borkmann:
"When adding connection tracking template rules to a netns, f.e. to
configure netfilter zones, the kernel will endlessly busy-loop as soon
as we try to delete the given netns in case there's at least one
template present, which is problematic i.e. if there is such bravery that
the priviledged user inside the netns is assumed untrusted.
Minimal example:
ip netns add foo
ip netns exec foo iptables -t raw -A PREROUTING -d 1.2.3.4 -j CT --zone 1
ip netns del foo
What happens is that when nf_ct_iterate_cleanup() is being called from
nf_conntrack_cleanup_net_list() for a provided netns, we always end up
with a net->ct.count > 0 and thus jump back to i_see_dead_people. We
don't get a soft-lockup as we still have a schedule() point, but the
serving CPU spins on 100% from that point onwards.
Since templates are normally allocated with nf_conntrack_alloc(), we
also bump net->ct.count. The issue why they are not yet nf_ct_put() is
because the per netns .exit() handler from x_tables (which would eventually
invoke xt_CT's xt_ct_tg_destroy() that drops reference on info->ct) is
called in the dependency chain at a *later* point in time than the per
netns .exit() handler for the connection tracker.
This is clearly a chicken'n'egg problem: after the connection tracker
.exit() handler, we've teared down all the connection tracking
infrastructure already, so rightfully, xt_ct_tg_destroy() cannot be
invoked at a later point in time during the netns cleanup, as that would
lead to a use-after-free. At the same time, we cannot make x_tables depend
on the connection tracker module, so that the xt_ct_tg_destroy() would
be invoked earlier in the cleanup chain."
Daniel confirms this has to do with the order in which modules are loaded or
having compiled nf_conntrack as modules while x_tables built-in. So we have no
guarantees regarding the order in which netns callbacks are executed.
Fix this by allocating the templates through kmalloc() from the respective
SYNPROXY and CT targets, so they don't depend on the conntrack kmem cache.
Then, release then via nf_ct_tmpl_free() from destroy_conntrack(). This branch
is marked as unlikely since conntrack templates are rarely allocated and only
from the configuration plane path.
Note that templates are not kept in any list to avoid further dependencies with
nf_conntrack anymore, thus, the tmpl larval list is removed.
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Tested-by: Daniel Borkmann <daniel@iogearbox.net>
Having to say
> #ifdef CONFIG_NET_NS
> struct net *net;
> #endif
in structures is a little bit wordy and a little bit error prone.
Instead it is possible to say:
> typedef struct {
> #ifdef CONFIG_NET_NS
> struct net *net;
> #endif
> } possible_net_t;
And then in a header say:
> possible_net_t net;
Which is cleaner and easier to use and easier to test, as the
possible_net_t is always there no matter what the compile options.
Further this allows read_pnet and write_pnet to be functions in all
cases which is better at catching typos.
This change adds possible_net_t, updates the definitions of read_pnet
and write_pnet, updates optional struct net * variables that
write_pnet uses on to have the type possible_net_t, and finally fixes
up the b0rked users of read_pnet and write_pnet.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The only user of nf_ct_conntrack_flush_report() was ctnetlink_del_conntrack().
After adding support for flushing connections with a given mark, this function
is no longer called.
Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
add a __nfct_init_offset annotation member to struct nf_conn to make
it clear which members are covered by the memset when the conntrack
is allocated.
This avoids zeroing timer_list and ct_net; both are already inited
explicitly.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Replace uses of get_cpu_var for address calculation through this_cpu_ptr.
Cc: netdev@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.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>
Changes while reading through the netfilter code.
Added hint about how conntrack nf_conn refcnt is accessed.
And renamed repl_hash to reply_hash for readability
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>
With this patch, the conntrack refcount is initially set to zero and
it is bumped once it is added to any of the list, so we fulfill
Eric's golden rule which is that all released objects always have a
refcount that equals zero.
Andrey Vagin reports that nf_conntrack_free can't be called for a
conntrack with non-zero ref-counter, because it can race with
nf_conntrack_find_get().
A conntrack slab is created with SLAB_DESTROY_BY_RCU. Non-zero
ref-counter says that this conntrack is used. So when we release
a conntrack with non-zero counter, we break this assumption.
CPU1 CPU2
____nf_conntrack_find()
nf_ct_put()
destroy_conntrack()
...
init_conntrack
__nf_conntrack_alloc (set use = 1)
atomic_inc_not_zero(&ct->use) (use = 2)
if (!l4proto->new(ct, skb, dataoff, timeouts))
nf_conntrack_free(ct); (use = 2 !!!)
...
__nf_conntrack_alloc (set use = 1)
if (!nf_ct_key_equal(h, tuple, zone))
nf_ct_put(ct); (use = 0)
destroy_conntrack()
/* continue to work with CT */
After applying the path "[PATCH] netfilter: nf_conntrack: fix RCU
race in nf_conntrack_find_get" another bug was triggered in
destroy_conntrack():
<4>[67096.759334] ------------[ cut here ]------------
<2>[67096.759353] kernel BUG at net/netfilter/nf_conntrack_core.c:211!
...
<4>[67096.759837] Pid: 498649, comm: atdd veid: 666 Tainted: G C --------------- 2.6.32-042stab084.18 #1 042stab084_18 /DQ45CB
<4>[67096.759932] RIP: 0010:[<ffffffffa03d99ac>] [<ffffffffa03d99ac>] destroy_conntrack+0x15c/0x190 [nf_conntrack]
<4>[67096.760255] Call Trace:
<4>[67096.760255] [<ffffffff814844a7>] nf_conntrack_destroy+0x17/0x30
<4>[67096.760255] [<ffffffffa03d9bb5>] nf_conntrack_find_get+0x85/0x130 [nf_conntrack]
<4>[67096.760255] [<ffffffffa03d9fb2>] nf_conntrack_in+0x352/0xb60 [nf_conntrack]
<4>[67096.760255] [<ffffffffa048c771>] ipv4_conntrack_local+0x51/0x60 [nf_conntrack_ipv4]
<4>[67096.760255] [<ffffffff81484419>] nf_iterate+0x69/0xb0
<4>[67096.760255] [<ffffffff814b5b00>] ? dst_output+0x0/0x20
<4>[67096.760255] [<ffffffff814845d4>] nf_hook_slow+0x74/0x110
<4>[67096.760255] [<ffffffff814b5b00>] ? dst_output+0x0/0x20
<4>[67096.760255] [<ffffffff814b66d5>] raw_sendmsg+0x775/0x910
<4>[67096.760255] [<ffffffff8104c5a8>] ? flush_tlb_others_ipi+0x128/0x130
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff814c136a>] inet_sendmsg+0x4a/0xb0
<4>[67096.760255] [<ffffffff81444e93>] ? sock_sendmsg+0x13/0x140
<4>[67096.760255] [<ffffffff81444f97>] sock_sendmsg+0x117/0x140
<4>[67096.760255] [<ffffffff8102e299>] ? native_smp_send_reschedule+0x49/0x60
<4>[67096.760255] [<ffffffff81519beb>] ? _spin_unlock_bh+0x1b/0x20
<4>[67096.760255] [<ffffffff8109d930>] ? autoremove_wake_function+0x0/0x40
<4>[67096.760255] [<ffffffff814960f0>] ? do_ip_setsockopt+0x90/0xd80
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff814457c9>] sys_sendto+0x139/0x190
<4>[67096.760255] [<ffffffff810efa77>] ? audit_syscall_entry+0x1d7/0x200
<4>[67096.760255] [<ffffffff810ef7c5>] ? __audit_syscall_exit+0x265/0x290
<4>[67096.760255] [<ffffffff81474daf>] compat_sys_socketcall+0x13f/0x210
<4>[67096.760255] [<ffffffff8104dea3>] ia32_sysret+0x0/0x5
I have reused the original title for the RFC patch that Andrey posted and
most of the original patch description.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Andrew Vagin <avagin@parallels.com>
Cc: Florian Westphal <fw@strlen.de>
Reported-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Andrew Vagin <avagin@parallels.com>
There are a mix of function prototypes with and without extern
in the kernel sources. Standardize on not using extern for
function prototypes.
Function prototypes don't need to be written with extern.
extern is assumed by the compiler. Its use is as unnecessary as
using auto to declare automatic/local variables in a block.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Let nf_ct_delete handle delivery of the DESTROY event.
Based on earlier patch from Pablo Neira.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Using 16 bits is too small, when many adjustments happen the offsets might
overflow and break the connection.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
ctnetlink contains copy-paste code from death_by_timeout. In order to
avoid changing both places in upcoming event delivery patch,
export death_by_timeout functionality and use it in the ctnetlink code.
Based on earlier patch from Pablo Neira.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Get rid of the confusing mix of pid and portid and use portid consistently
for all netlink related socket identities.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch modifies the conntrack subsystem so that all existing
allocated conntrack objects can be found in any of the following
places:
* the hash table, this is the typical place for alive conntrack objects.
* the unconfirmed list, this is the place for newly created conntrack objects
that are still traversing the stack.
* the dying list, this is where you can find conntrack objects that are dying
or that should die anytime soon (eg. once the destroy event is delivered to
the conntrackd daemon).
Thus, we make sure that we follow the track for all existing conntrack
objects. This patch, together with some extension of the ctnetlink interface
to dump the content of the dying and unconfirmed lists, will help in case
to debug suspected nf_conn object leaks.
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>
this_cpu_inc() is IRQ safe and faster than
local_bh_disable()/__this_cpu_inc()/local_bh_enable(), at least on x86.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Marcell Zambo and Janos Farago noticed and reported that when
new conntrack entries are added via netlink and the conntrack table
gets full, soft lockup happens. This is because the nf_conntrack_lock
is held while nf_conntrack_alloc is called, which is in turn wants
to lock nf_conntrack_lock while evicting entries from the full table.
The patch fixes the soft lockup with limiting the holding of the
nf_conntrack_lock to the minimum, where it's absolutely required.
It required to extend (and thus change) nf_conntrack_hash_insert
so that it makes sure conntrack and ctnetlink do not add the same entry
twice to the conntrack table.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Varsha Rao