Now that the egress function can be called from egress hook, we need
to avoid recursive calls into the nf_tables traverser, else crash.
Fixes: f87b9464d1 ("netfilter: nft_fwd_netdev: Support egress hook")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Eric reports skb_under_panic when using dup/fwd via bond+egress hook.
Before pushing mac header, we should make sure that we're called from
ingress to put back what was pulled earlier.
In egress case, the MAC header is already there; we should leave skb
alone.
While at it be more careful here: skb might have been altered and
headroom reduced, so add a skb_cow() before so that headroom is
increased if necessary.
nf_do_netdev_egress() assumes skb ownership (it normally ends with
a call to dev_queue_xmit), so we must free the packet on error.
Fixes: f87b9464d1 ("netfilter: nft_fwd_netdev: Support egress hook")
Reported-by: Eric Garver <eric@garver.life>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
syzbot reports:
BUG: KASAN: slab-out-of-bounds in __list_del_entry_valid+0xcc/0xf0 lib/list_debug.c:42
[..]
list_del include/linux/list.h:148 [inline]
cttimeout_net_exit+0x211/0x540 net/netfilter/nfnetlink_cttimeout.c:617
Problem is the wrong name of the list member, so container_of() result is wrong.
Reported-by: <syzbot+92968395eedbdbd3617d@syzkaller.appspotmail.com>
Fixes: 78222bacfc ("netfilter: cttimeout: decouple unlink and free on netns destruction")
Signed-off-by: Florian Westphal <fw@strlen.de>
bh might occur while updating per-cpu rnd_state from user context,
ie. local_out path.
BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725
caller is nft_ng_random_eval+0x24/0x54 [nft_numgen]
Call Trace:
check_preemption_disabled+0xde/0xe0
nft_ng_random_eval+0x24/0x54 [nft_numgen]
Use the random driver instead, this also avoids need for local prandom
state. Moreover, prandom now uses the random driver since d4150779e6
("random32: use real rng for non-deterministic randomness").
Based on earlier patch from Pablo Neira.
Fixes: 6b2faee0ca ("netfilter: nft_meta: place prandom handling in a helper")
Fixes: 978d8f9055 ("netfilter: nft_numgen: add map lookups for numgen random operations")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If user requests for NFT_CHAIN_HW_OFFLOAD, then check if either device
provides the .ndo_setup_tc interface or there is an indirect flow block
that has been registered. Otherwise, bail out early from the preparation
phase. Moreover, validate that family == NFPROTO_NETDEV and hook is
NF_NETDEV_INGRESS.
Fixes: c9626a2cbd ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Abort path release flow rule object, however, commit path does not.
Update code to destroy these objects before releasing the transaction.
Fixes: c9626a2cbd ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Release the list of new hooks that are pending to be registered in case
that unsupported flowtable flags are provided.
Fixes: 78d9f48f7f ("netfilter: nf_tables: add devices to existing flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The hook list is used if nft_trans_flowtable_update(trans) == true. However,
initialize this list for other cases for safety reasons.
Fixes: 78d9f48f7f ("netfilter: nf_tables: add devices to existing flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Remove inactive bool field in nft_hook object that was introduced in
abadb2f865 ("netfilter: nf_tables: delete devices from flowtable").
Move stale flowtable hooks to transaction list instead.
Deleting twice the same device does not result in ENOENT.
Fixes: abadb2f865 ("netfilter: nf_tables: delete devices from flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use kfree_rcu(ptr, rcu) variant instead as described by ae089831ff
("netfilter: nf_tables: prefer kfree_rcu(ptr, rcu) variant").
Fixes: f9a43007d3 ("netfilter: nf_tables: double hook unregistration in netns path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When no l3 address is given, priv->family is set to NFPROTO_INET and
the evaluation function isn't called.
Call it too so l4-only rewrite can work.
Also add a test case for this.
Fixes: a33f387ecd ("netfilter: nft_nat: allow to specify layer 4 protocol NAT only")
Reported-by: Yi Chen <yiche@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For snat and dnat cases, the saddr should be taken from reverse tuple.
Fixes: 3412e16418 (netfilter: flowtable: nft_flow_route use more data for reverse route)
Signed-off-by: wenxu <wenxu@chinatelecom.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The nf_flow_table gets route through ip_route_output_key. If the saddr
is not local one, then FLOWI_FLAG_ANYSRC flag should be set. Without
this flag, the route lookup for other_dst will fail.
Fixes: 3412e16418 (netfilter: flowtable: nft_flow_route use more data for reverse route)
Signed-off-by: wenxu <wenxu@chinatelecom.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
__nft_release_hooks() is called from pre_netns exit path which
unregisters the hooks, then the NETDEV_UNREGISTER event is triggered
which unregisters the hooks again.
[ 565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270
[...]
[ 565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G E 5.18.0-rc7+ #27
[ 565.253682] Workqueue: netns cleanup_net
[ 565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270
[...]
[ 565.297120] Call Trace:
[ 565.300900] <TASK>
[ 565.304683] nf_tables_flowtable_event+0x16a/0x220 [nf_tables]
[ 565.308518] raw_notifier_call_chain+0x63/0x80
[ 565.312386] unregister_netdevice_many+0x54f/0xb50
Unregister and destroy netdev hook from netns pre_exit via kfree_rcu
so the NETDEV_UNREGISTER path see unregistered hooks.
Fixes: 767d1216bf ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
clean_net() runs in workqueue while walking over the lists, grab mutex.
Fixes: 767d1216bf ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add several sanity checks for nft_set_desc_concat_parse():
- validate desc->field_count not larger than desc->field_len array.
- field length cannot be larger than desc->field_len (ie. U8_MAX)
- total length of the concatenation cannot be larger than register array.
Joint work with Florian Westphal.
Fixes: f3a2181e16 ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reported-by: <zhangziming.zzm@antgroup.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
syzbot reports:
BUG: KASAN: slab-out-of-bounds in __list_del_entry_valid+0xcc/0xf0 lib/list_debug.c:42
[..]
list_del include/linux/list.h:148 [inline]
cttimeout_net_exit+0x211/0x540 net/netfilter/nfnetlink_cttimeout.c:617
No reproducer so far. Looking at recent changes in this area
its clear that the free_head must not be at the end of the
structure because nf_ct_timeout structure has variable size.
Reported-by: <syzbot+92968395eedbdbd3617d@syzkaller.appspotmail.com>
Fixes: 78222bacfc ("netfilter: cttimeout: decouple unlink and free on netns destruction")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
syzbot reports following warn:
WARNING: CPU: 0 PID: 3600 at net/netfilter/nfnetlink.c:703 nfnetlink_unbind+0x357/0x3b0 net/netfilter/nfnetlink.c:694
The syzbot generated program does this:
socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER) = 3
setsockopt(3, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, [1], 4) = 0
... which triggers 'WARN_ON_ONCE(nfnlnet->ctnetlink_listeners == 0)' check.
Instead of counting, just enable reporting for every bind request
and check if we still have listeners on unbind.
While at it, also add the needed bounds check on nfnl_group2type[]
access.
Reported-by: <syzbot+4903218f7fba0a2d6226@syzkaller.appspotmail.com>
Reported-by: <syzbot+afd2d80e495f96049571@syzkaller.appspotmail.com>
Fixes: 2794cdb0b9 ("netfilter: nfnetlink: allow to detect if ctnetlink listeners exist")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When cloning a packet-based limit expression, copy the cost value as
well. Otherwise the new limit is not functional anymore.
Fixes: 3b9e2ea6c1 ("netfilter: nft_limit: move stateful fields out of expression data")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Since 3e135cd499 ("netfilter: nft_dynset: dynamic stateful expression
instantiation"), it is possible to attach stateful expressions to set
elements.
cd5125d8f5 ("netfilter: nf_tables: split set destruction in deactivate
and destroy phase") introduces conditional destruction on the object to
accomodate transaction semantics.
nft_expr_init() calls expr->ops->init() first, then check for
NFT_STATEFUL_EXPR, this stills allows to initialize a non-stateful
lookup expressions which points to a set, which might lead to UAF since
the set is not properly detached from the set->binding for this case.
Anyway, this combination is non-sense from nf_tables perspective.
This patch fixes this problem by checking for NFT_STATEFUL_EXPR before
expr->ops->init() is called.
The reporter provides a KASAN splat and a poc reproducer (similar to
those autogenerated by syzbot to report use-after-free errors). It is
unknown to me if they are using syzbot or if they use similar automated
tool to locate the bug that they are reporting.
For the record, this is the KASAN splat.
[ 85.431824] ==================================================================
[ 85.432901] BUG: KASAN: use-after-free in nf_tables_bind_set+0x81b/0xa20
[ 85.433825] Write of size 8 at addr ffff8880286f0e98 by task poc/776
[ 85.434756]
[ 85.434999] CPU: 1 PID: 776 Comm: poc Tainted: G W 5.18.0+ #2
[ 85.436023] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
Fixes: 0b2d8a7b63 ("netfilter: nf_tables: add helper functions for expression handling")
Reported-and-tested-by: Aaron Adams <edg-e@nccgroup.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, misc
updates and fallout fixes from recent Florian's code rewritting (from
last pull request):
1) Use new flowi4_l3mdev field in ip_route_me_harder(), from Martin Willi.
2) Avoid unnecessary GC with a timestamp in conncount, from William Tu
and Yifeng Sun.
3) Remove TCP conntrack debugging, from Florian Westphal.
4) Fix compilation warning in ctnetlink, from Florian.
* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
netfilter: ctnetlink: fix up for "netfilter: conntrack: remove unconfirmed list"
netfilter: conntrack: remove pr_debug callsites from tcp tracker
netfilter: nf_conncount: reduce unnecessary GC
netfilter: Use l3mdev flow key when re-routing mangled packets
====================
Link: https://lore.kernel.org/r/20220519220206.722153-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Either userspace or kernelspace need to pre-fetch keys inconditionally
before comparisons for this to work. Otherwise, register tracking data
is misleading and it might result in reducing expressions which are not
yet registers.
First expression is also guaranteed to be evaluated always, however,
certain expressions break before writing data to registers, before
comparing the data, leaving the register in undetermined state.
This patch disables this infrastructure by now.
Fixes: b2d306542f ("netfilter: nf_tables: do not reduce read-only expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Fixes sporadic IPv6 packet loss when flow offloading is enabled.
IPv6 route GC and flowtable GC are not synchronized.
When dst_cache becomes stale and a packet passes through the flow before
the flowtable GC teardowns it, the packet can be dropped.
So, it is necessary to check dst every time in packet path.
Fixes: 227e1e4d0d ("netfilter: nf_flowtable: skip device lookup from interface index")
Signed-off-by: Ritaro Takenaka <ritarot634@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch addresses three possible problems:
1. ct gc may race to undo the timeout adjustment of the packet path, leaving
the conntrack entry in place with the internal offload timeout (one day).
2. ct gc removes the ct because the IPS_OFFLOAD_BIT is not set and the CLOSE
timeout is reached before the flow offload del.
3. tcp ct is always set to ESTABLISHED with a very long timeout
in flow offload teardown/delete even though the state might be already
CLOSED. Also as a remark we cannot assume that the FIN or RST packet
is hitting flow table teardown as the packet might get bumped to the
slow path in nftables.
This patch resets IPS_OFFLOAD_BIT from flow_offload_teardown(), so
conntrack handles the tcp rst/fin packet which triggers the CLOSE/FIN
state transition.
Moreover, teturn the connection's ownership to conntrack upon teardown
by clearing the offload flag and fixing the established timeout value.
The flow table GC thread will asynchonrnously free the flow table and
hardware offload entries.
Before this patch, the IPS_OFFLOAD_BIT remained set for expired flows on
which is also misleading since the flow is back to classic conntrack
path.
If nf_ct_delete() removes the entry from the conntrack table, then it
calls nf_ct_put() which decrements the refcnt. This is not a problem
because the flowtable holds a reference to the conntrack object from
flow_offload_alloc() path which is released via flow_offload_free().
This patch also updates nft_flow_offload to skip packets in SYN_RECV
state. Since we might miss or bump packets to slow path, we do not know
what will happen there while we are still in SYN_RECV, this patch
postpones offload up to the next packet which also aligns to the
existing behaviour in tc-ct.
flow_offload_teardown() does not reset the existing tcp state from
flow_offload_fixup_tcp() to ESTABLISHED anymore, packets bump to slow
path might have already update the state to CLOSE/FIN.
Joint work with Oz and Sven.
Fixes: 1e5b2471bc ("netfilter: nf_flow_table: teardown flow timeout race")
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After merging the net-next tree, today's linux-next build (powerpc
ppc64_defconfig) produced this warning:
nf_conntrack_netlink.c:1717 warning: 'ctnetlink_dump_one_entry' defined but not used
Fixes: 8a75a2c174 ("netfilter: conntrack: remove unconfirmed list")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Florian Westphal <fw@strlen.de>
They are either obsolete or useless.
Those in the normal processing path cannot be enabled on a production
system; they generate too much noise.
One pr_debug call resides in an error path and does provide useful info,
merge it with the existing nf_log_invalid().
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently nf_conncount can trigger garbage collection (GC)
at multiple places. Each GC process takes a spin_lock_bh
to traverse the nf_conncount_list. We found that when testing
port scanning use two parallel nmap, because the number of
connection increase fast, the nf_conncount_count and its
subsequent call to __nf_conncount_add take too much time,
causing several CPU lockup. This happens when user set the
conntrack limit to +20,000, because the larger the limit,
the longer the list that GC has to traverse.
The patch mitigate the performance issue by avoiding unnecessary
GC with a timestamp. Whenever nf_conncount has done a GC,
a timestamp is updated, and beforce the next time GC is
triggered, we make sure it's more than a jiffies.
By doin this we can greatly reduce the CPU cycles and
avoid the softirq lockup.
To reproduce it in OVS,
$ ovs-appctl dpctl/ct-set-limits zone=1,limit=20000
$ ovs-appctl dpctl/ct-get-limits
At another machine, runs two nmap
$ nmap -p1- <IP>
$ nmap -p1- <IP>
Signed-off-by: William Tu <u9012063@gmail.com>
Co-authored-by: Yifeng Sun <pkusunyifeng@gmail.com>
Reported-by: Greg Rose <gvrose8192@gmail.com>
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When running a combination of PPPoE on top of a VLAN, we need to set
info->outdev to the PPPoE device, otherwise PPPoE encap is skipped
during software offload.
Fixes: 72efd585f7 ("netfilter: flowtable: add pppoe support")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The dst entry does not contain a valid hardware address, so skip the lookup
in order to avoid running into errors here.
The proper hardware address is filled in from nft_dev_path_info
Fixes: 72efd585f7 ("netfilter: flowtable: add pppoe support")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If a flow cannot be offloaded, the code currently repeatedly tries again as
quickly as possible, which can significantly increase system load.
Fix this by limiting flow timeout update and hardware offload retry to once
per second.
Fixes: c07531c01d ("netfilter: flowtable: Remove redundant hw refresh bit")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
This is v2 including deadlock fix in conntrack ecache rework
reported by Jakub Kicinski.
The following patchset contains Netfilter updates for net-next,
mostly updates to conntrack from Florian Westphal.
1) Add a dedicated list for conntrack event redelivery.
2) Include event redelivery list in conntrack dumps of dying type.
3) Remove per-cpu dying list for event redelivery, not used anymore.
4) Add netns .pre_exit to cttimeout to zap timeout objects before
synchronize_rcu() call.
5) Remove nf_ct_unconfirmed_destroy.
6) Add generation id for conntrack extensions for conntrack
timeout and helpers.
7) Detach timeout policy from conntrack on cttimeout module removal.
8) Remove __nf_ct_unconfirmed_destroy.
9) Remove unconfirmed list.
10) Remove unconditional local_bh_disable in init_conntrack().
11) Consolidate conntrack iterator nf_ct_iterate_cleanup().
12) Detect if ctnetlink listeners exist to short-circuit event
path early.
13) Un-inline nf_ct_ecache_ext_add().
14) Add nf_conntrack_events autodetect ctnetlink listener mode
and make it default.
15) Add nf_ct_ecache_exist() to check for event cache extension.
16) Extend flowtable reverse route lookup to include source, iif,
tos and mark, from Sven Auhagen.
17) Do not verify zero checksum UDP packets in nf_reject,
from Kevin Mitchell.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
When creating a flow table entry, the reverse route is looked
up based on the current packet.
There can be scenarios where the user creates a custom ip rule
to route the traffic differently.
In order to support those scenarios, the lookup needs to add
more information based on the current packet.
The patch adds multiple new information to the route lookup.
Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This adds the new nf_conntrack_events=2 mode and makes it the
default.
This leverages the earlier flag in struct net to allow to avoid
the event extension as long as no event listener is active in
the namespace.
This avoids, for most cases, allocation of ct->ext area.
A followup patch will take further advantage of this by avoiding
calls down into the event framework if the extension isn't present.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Only called when new ct is allocated or the extension isn't present.
This function will be extended, place this in the conntrack module
instead of inlining.
The callers already depend on nf_conntrack module.
Return value is changed to bool, noone used the returned pointer.
Make sure that the core drops the newly allocated conntrack
if the extension is requested but can't be added.
This makes it necessary to ifdef the section, as the stub
always returns false we'd drop every new conntrack if the
the ecache extension is disabled in kconfig.
Add from data path (xt_CT, nft_ct) is unchanged.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
At this time, every new conntrack gets the 'event cache extension'
enabled for it.
This is because the 'net.netfilter.nf_conntrack_events' sysctl defaults
to 1.
Changing the default to 0 means that commands that rely on the event
notification extension, e.g. 'conntrack -E' or conntrackd, stop working.
We COULD detect if there is a listener by means of
'nfnetlink_has_listeners()' and only add the extension if this is true.
The downside is a dependency from conntrack module to nfnetlink module.
This adds a different way: inc/dec a counter whenever a ctnetlink group
is being (un)subscribed and toggle a flag in struct net.
Next patches will take advantage of this and will only add the event
extension if the flag is set.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds a structure to collect all the context data that is
passed to the cleanup iterator.
struct nf_ct_iter_data {
struct net *net;
void *data;
u32 portid;
int report;
};
There is a netns field that allows to clean up conntrack entries
specifically owned by the specified netns.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Now that the conntrack entry isn't placed on the pcpu list anymore the
bh only needs to be disabled in the 'expectation present' case.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Its not needed anymore:
A. If entry is totally new, then the rcu-protected resource
must already have been removed from global visibility before call
to nf_ct_iterate_destroy.
B. If entry was allocated before, but is not yet in the hash table
(uncofirmed case), genid gets incremented and synchronize_rcu() call
makes sure access has completed.
C. Next attempt to peek at extension area will fail for unconfirmed
conntracks, because ext->genid != genid.
D. Conntracks in the hash are iterated as before.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Increment the extid on module removal; this makes sure that even
in extreme cases any old uncofirmed entry that happened to be kept
e.g. on nfnetlink_queue list will not trip over a stale timeout
reference.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Multiple netfilter extensions store pointers to external data
in their extension area struct.
Examples:
1. Timeout policies
2. Connection tracking helpers.
No references are taken for these.
When a helper or timeout policy is removed, the conntrack table gets
traversed and affected extensions are cleared.
Conntrack entries not yet in the hashtable are referenced via a special
list, the unconfirmed list.
On removal of a policy or connection tracking helper, the unconfirmed
list gets traversed an all entries are marked as dying, this prevents
them from getting committed to the table at insertion time: core checks
for dying bit, if set, the conntrack entry gets destroyed at confirm
time.
The disadvantage is that each new conntrack has to be added to the percpu
unconfirmed list, and each insertion needs to remove it from this list.
The list is only ever needed when a policy or helper is removed -- a rare
occurrence.
Add a generation ID count: Instead of adding to the list and then
traversing that list on policy/helper removal, increment a counter
that is stored in the extension area.
For unconfirmed conntracks, the extension has the genid valid at ct
allocation time.
Removal of a helper/policy etc. increments the counter.
At confirmation time, validate that ext->genid == global_id.
If the stored number is not the same, do not allow the conntrack
insertion, just like as if a confirmed-list traversal would have flagged
the entry as dying.
After insertion, the genid is no longer relevant (conntrack entries
are now reachable via the conntrack table iterators and is set to 0.
This allows removal of the percpu unconfirmed list.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This helper tags connections not yet in the conntrack table as
dying. These nf_conn entries will be dropped instead when the
core attempts to insert them from the input or postrouting
'confirm' hook.
After the previous change, the entries get unlinked from the
list earlier, so that by the time the actual exit hook runs,
new connections no longer have a timeout policy assigned.
Its enough to walk the hashtable instead.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Make it so netns pre_exit unlinks the objects from the pernet list, so
they cannot be found anymore.
netns core issues a synchronize_rcu() before calling the exit hooks so
any the time the exit hooks run unconfirmed nf_conn entries have been
free'd or they have been committed to the hashtable.
The exit hook still tags unconfirmed entries as dying, this can
now be removed in a followup change.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Its no longer needed. Entries that need event redelivery are placed
on the new pernet dying list.
The advantage is that there is no need to take additional spinlock on
conntrack removal unless event redelivery failed or the conntrack entry
was never added to the table in the first place (confirmed bit not set).
The IPS_CONFIRMED bit now needs to be set as soon as the entry has been
unlinked from the unconfirmed list, else the destroy function may
attempt to unlink it a second time.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The new pernet dying list includes conntrack entries that await
delivery of the 'destroy' event via ctnetlink.
The old percpu dying list will be removed soon.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This disentangles event redelivery and the percpu dying list.
Because entries are now stored on a dedicated list, all
entries are in NFCT_ECACHE_DESTROY_FAIL state and all entries
still have confirmed bit set -- the reference count is at least 1.
The 'struct net' back-pointer can be removed as well.
The pcpu dying list will be removed eventually, it has no functionality.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Florian Westphal