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In case the conntrack is clashing, insertion can free skb->_nfct and
set skb->_nfct to the already-confirmed entry.
This wasn't found before because the conntrack entry and the extension
space used to free'd after an rcu grace period, plus the race needs
events enabled to trigger.
Reported-by: <syzbot+793a590957d9c1b96620@syzkaller.appspotmail.com>
Fixes: 71d8c47fc653 ("netfilter: conntrack: introduce clash resolution on insertion race")
Fixes: 2ad9d7747c10 ("netfilter: conntrack: free extension area immediately")
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>
The checksum is optional for UDP packets. However nf_reject would
previously require a valid checksum to elicit a response such as
ICMP_DEST_UNREACH.
Add some logic to nf_reject_verify_csum to determine if a UDP packet has
a zero checksum and should therefore not be verified.
Signed-off-by: Kevin Mitchell <kevmitch@arista.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The pointer check usually results in a 'false positive': its likely
that the ctnetlink module is loaded but no event monitoring is enabled.
After recent change to autodetect ctnetlink usage and only allocate
the ecache extension if a listener is active, check if the extension
is present on a given conntrack.
If its not there, there is nothing to report and calls to the
notification framework can be elided.
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>
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>
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>
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>
This makes it easier for a followup patch to only expose ecache
related parts of nf_conntrack_net structure.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The fib expression stores to a register, so we can't add empty stub.
Check that the register that is being written is in fact redundant.
In most cases, this is expected to cancel tracking as re-use is
unlikely.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
its enough to export the meta get reduce helper and then call it
from nft_meta_bridge too.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Output of expressions might be larger than one single register, this might
clobber existing data. Reset tracking for all destination registers that
required to store the expression output.
This patch adds three new helper functions:
- nft_reg_track_update: cancel previous register tracking and update it.
- nft_reg_track_cancel: cancel any previous register tracking info.
- __nft_reg_track_cancel: cancel only one single register tracking info.
Partial register clobbering detection is also supported by checking the
.num_reg field which describes the number of register that are used.
This patch updates the following expressions:
- meta_bridge
- bitwise
- byteorder
- meta
- payload
to use these helper functions.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Skip register tracking for expressions that perform read-only operations
on the registers. Define and use a cookie pointer NFT_REDUCE_READONLY to
avoid defining stubs for these expressions.
This patch re-enables register tracking which was disabled in ed5f85d42290
("netfilter: nf_tables: disable register tracking"). Follow up patches
add remaining register tracking for existing expressions.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The function sets the pernet boolean to avoid the spurious warning from
nf_ct_lookup_helper() when assigning conntrack helpers via nftables.
Fixes: 1a64edf54f55 ("netfilter: nft_ct: add helper set support")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
nf_flow_offload_inet_hook() does not check for 802.1q and PPPoE.
Fetch inner ethertype from these encapsulation protocols.
Fixes: 72efd585f714 ("netfilter: flowtable: add pppoe support")
Fixes: 4cd91f7c290f ("netfilter: flowtable: add vlan support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This was a prerequisite for the ill-fated
"netfilter: nat: force port remap to prevent shadowing well-known ports".
As this has been reverted, this change can be backed out too.
Signed-off-by: Florian Westphal <fw@strlen.de>
After cited commit optimizted hw insertion, flow table entries are
populated with ifindex information which was intended to only be used
for HW offload. This tuple ifindex is hashed in the flow table key, so
it must be filled for lookup to be successful. But tuple ifindex is only
relevant for the netfilter flowtables (nft), so it's not filled in
act_ct flow table lookup, resulting in lookup failure, and no SW
offload and no offload teardown for TCP connection FIN/RST packets.
To fix this, add new tc ifindex field to tuple, which will
only be used for offloading, not for lookup, as it will not be
part of the tuple hash.
Fixes: 9795ded7f924 ("net/sched: act_ct: Fill offloading tuple iifidx")
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Eric Dumazet says:
The sock_hold() side seems suspect, because there is no guarantee
that sk_refcnt is not already 0.
On failure, we cannot queue the packet and need to indicate an
error. The packet will be dropped by the caller.
v2: split skb prefetch hunk into separate change
Fixes: 271b72c7fa82c ("udp: RCU handling for Unicast packets.")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
immediate verdict expression needs to allocate one slot in the flow offload
action array, however, immediate data expression does not need to do so.
fwd and dup expression need to allocate one slot, this is missing.
Add a new offload_action interface to report if this expression needs to
allocate one slot in the flow offload action array.
Fixes: be2861dc36d7 ("netfilter: nft_{fwd,dup}_netdev: add offload support")
Reported-and-tested-by: Nick Gregory <Nick.Gregory@Sophos.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Allow up to 16-byte comparisons with a new cmp fast version. Use two
64-bit words and calculate the mask representing the bits to be
compared. Make sure the comparison is 64-bit aligned and avoid
out-of-bound memory access on registers.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Instead of two exported functions, export a single option structure.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For updating eache missed value we can use cmpxchg.
This also avoids need to disable BH.
kernel robot reported build failure on v1 because not all arches support
cmpxchg for u16, so extend this to u32.
This doesn't increase struct size, existing padding is used.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
These no longer register/unregister a meaningful structure so remove it.
Cc: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The nat module already exposes a few functions to the conntrack core.
Move the nat extension destroy hook to it.
After this, no conntrack extension needs a destroy hook.
'struct nf_ct_ext_type' and the register/unregister api can be removed
in a followup patch.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
No need to specify this in the registration modules, we already
collect all sizes for build-time checks on the maximum combined size.
After this change, all extensions except nat have no meaningful content
in their nf_ct_ext_type struct definition.
Next patch handles nat, this will then allow to remove the dynamic
register api completely.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
All extensions except one need 8 byte alignment, so just make that the
default.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This change adds conntrack lookup helpers using the unstable kfunc call
interface for the XDP and TC-BPF hooks. The primary usecase is
implementing a synproxy in XDP, see Maxim's patchset [0].
Export get_net_ns_by_id as nf_conntrack_bpf.c needs to call it.
This object is only built when CONFIG_DEBUG_INFO_BTF_MODULES is enabled.
[0]: https://lore.kernel.org/bpf/20211019144655.3483197-1-maximmi@nvidia.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220114163953.1455836-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following patchset contains Netfilter updates for net-next. This
includes one patch to update ovs and act_ct to use nf_ct_put() instead
of nf_conntrack_put().
1) Add netns_tracker to nfnetlink_log and masquerade, from Eric Dumazet.
2) Remove redundant rcu read-size lock in nf_tables packet path.
3) Replace BUG() by WARN_ON_ONCE() in nft_payload.
4) Consolidate rule verdict tracing.
5) Replace WARN_ON() by WARN_ON_ONCE() in nf_tables core.
6) Make counter support built-in in nf_tables.
7) Add new field to conntrack object to identify locally generated
traffic, from Florian Westphal.
8) Prevent NAT from shadowing well-known ports, from Florian Westphal.
9) Merge nf_flow_table_{ipv4,ipv6} into nf_flow_table_inet, also from
Florian.
10) Remove redundant pointer in nft_pipapo AVX2 support, from Colin Ian King.
11) Replace opencoded max() in conntrack, from Jiapeng Chong.
12) Update conntrack to use refcount_t API, from Florian Westphal.
13) Move ip_ct_attach indirection into the nf_ct_hook structure.
14) Constify several pointer object in the netfilter codebase,
from Florian Westphal.
15) Tree-wide replacement of nf_conntrack_put() by nf_ct_put(), also
from Florian.
16) Fix egress splat due to incorrect rcu notation, from Florian.
17) Move stateful fields of connlimit, last, quota, numgen and limit
out of the expression data area.
18) Build a blob to represent the ruleset in nf_tables, this is a
requirement of the new register tracking infrastructure.
19) Add NFT_REG32_NUM to define the maximum number of 32-bit registers.
20) Add register tracking infrastructure to skip redundant
store-to-register operations, this includes support for payload,
meta and bitwise expresssions.
* git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next: (32 commits)
netfilter: nft_meta: cancel register tracking after meta update
netfilter: nft_payload: cancel register tracking after payload update
netfilter: nft_bitwise: track register operations
netfilter: nft_meta: track register operations
netfilter: nft_payload: track register operations
netfilter: nf_tables: add register tracking infrastructure
netfilter: nf_tables: add NFT_REG32_NUM
netfilter: nf_tables: add rule blob layout
netfilter: nft_limit: move stateful fields out of expression data
netfilter: nft_limit: rename stateful structure
netfilter: nft_numgen: move stateful fields out of expression data
netfilter: nft_quota: move stateful fields out of expression data
netfilter: nft_last: move stateful fields out of expression data
netfilter: nft_connlimit: move stateful fields out of expression data
netfilter: egress: avoid a lockdep splat
net: prefer nf_ct_put instead of nf_conntrack_put
netfilter: conntrack: avoid useless indirection during conntrack destruction
netfilter: make function op structures const
netfilter: core: move ip_ct_attach indirection to struct nf_ct_hook
netfilter: conntrack: convert to refcount_t api
...
====================
Link: https://lore.kernel.org/r/20220109231640.104123-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Check if the destination register already contains the data that this
bitwise expression performs. This allows to skip this redundant
operation.
If the destination contains a different bitwise operation, cancel the
register tracking information. If the destination contains no bitwise
operation, update the register tracking information.
Update the payload and meta expression to check if this bitwise
operation has been already performed on the register. Hence, both the
payload/meta and the bitwise expressions are reduced.
There is also a special case: If source register != destination register
and source register is not updated by a previous bitwise operation, then
transfer selector from the source register to the destination register.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds new infrastructure to skip redundant selector store
operations on the same register to achieve a performance boost from
the packet path.
This is particularly noticeable in pure linear rulesets but it also
helps in rulesets which are already heaving relying in maps to avoid
ruleset linear inspection.
The idea is to keep data of the most recurrent store operations on
register to reuse them with cmp and lookup expressions.
This infrastructure allows for dynamic ruleset updates since the ruleset
blob reduction happens from the kernel.
Userspace still needs to be updated to maximize register utilization to
cooperate to improve register data reuse / reduce number of store on
register operations.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a definition including the maximum number of 32-bits registers that
are used a scratchpad memory area to store data.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds a blob layout per chain to represent the ruleset in the
packet datapath.
size (unsigned long)
struct nft_rule_dp
struct nft_expr
...
struct nft_rule_dp
struct nft_expr
...
struct nft_rule_dp (is_last=1)
The new structure nft_rule_dp represents the rule in a more compact way
(smaller memory footprint) compared to the control-plane nft_rule
structure.
The ruleset blob is a read-only data structure. The first field contains
the blob size, then the rules containing expressions. There is a trailing
rule which is used by the tracing infrastructure which is equivalent to
the NULL rule marker in the previous representation. The blob size field
does not include the size of this trailing rule marker.
The ruleset blob is generated from the commit path.
This patch reuses the infrastructure available since 0cbc06b3faba
("netfilter: nf_tables: remove synchronize_rcu in commit phase") to
build the array of rules per chain.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
nf_ct_put() results in a usesless indirection:
nf_ct_put -> nf_conntrack_put -> nf_conntrack_destroy -> rcu readlock +
indirect call of ct_hooks->destroy().
There are two _put helpers:
nf_ct_put and nf_conntrack_put. The latter is what should be used in
code that MUST NOT cause a linker dependency on the conntrack module
(e.g. calls from core network stack).
Everyone else should call nf_ct_put() instead.
A followup patch will convert a few nf_conntrack_put() calls to
nf_ct_put(), in particular from modules that already have a conntrack
dependency such as act_ct or even nf_conntrack itself.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Driver offloading ct tuples can use the information of which devices
received the packets that created the offloaded connections, to
more efficiently offload them only to the relevant device.
Add new act_ct nf conntrack extension, which is used to store the skb
devices before offloading the connection, and then fill in the tuple
iifindex so drivers can get the device via metadata dissector match.
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows to identify flows that originate from local machine
in a followup patch.
It would be possible to make this a ->status bit instead.
For now I did not do that yet because I don't have a use-case for
exposing this info to userspace.
If one comes up the toggle can be replaced with a status bit.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Allow to match and mangle on inner headers / payload data after the
transport header. There is a new field in the pktinfo structure that
stores the inner header offset which is calculated only when requested.
Only TCP and UDP supported at this stage.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The only factor differentiating per-CPU bstats data type (struct
gnet_stats_basic_cpu) from the packed non-per-CPU one (struct
gnet_stats_basic_packed) was a u64_stats sync point inside the former.
The two data types are now equivalent: earlier commits added a u64_stats
sync point to the latter.
Combine both data types into "struct gnet_stats_basic_sync". This
eliminates redundancy and simplifies the bstats read/write APIs.
Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit
architectures, u64_stats sync points do not use sequence counter
protection.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Include the NLM_F_CREATE and NLM_F_EXCL flags in netlink event
notifications, otherwise userspace cannot distiguish between create and
add commands.
Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
