7246 Commits

Author SHA1 Message Date
Zhengchuan Liang
62443dc211 netfilter: require Ethernet MAC header before using eth_hdr()
`ip6t_eui64`, `xt_mac`, the `bitmap:ip,mac`, `hash:ip,mac`, and
`hash:mac` ipset types, and `nf_log_syslog` access `eth_hdr(skb)`
after either assuming that the skb is associated with an Ethernet
device or checking only that the `ETH_HLEN` bytes at
`skb_mac_header(skb)` lie between `skb->head` and `skb->data`.

Make these paths first verify that the skb is associated with an
Ethernet device, that the MAC header was set, and that it spans at
least a full Ethernet header before accessing `eth_hdr(skb)`.

Suggested-by: Florian Westphal <fw@strlen.de>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:27 +02:00
Florian Westphal
1dfd95bdf4 netfilter: nft_fwd_netdev: check ttl/hl before forwarding
Drop packets if their ttl/hl is too small for forwarding.

Fixes: d32de98ea7 ("netfilter: nft_fwd_netdev: allow to forward packets via neighbour layer")
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:27 +02:00
Gustavo A. R. Silva
f30e5a7291 netfilter: x_tables: Avoid a couple -Wflex-array-member-not-at-end warnings
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Use the TRAILING_OVERLAP() helper to fix the following warnings:

1 net/netfilter/x_tables.c:816:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
1 net/netfilter/x_tables.c:811:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

This helper creates a union between a flexible-array member (FAM)
and a set of members that would otherwise follow it. This overlays
the trailing members onto the FAM while preserving the original
memory layout.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:27 +02:00
Fernando Fernandez Mancera
84dee05d9d netfilter: conntrack: remove UDP-Lite conntrack support
UDP-Lite (RFC 3828) socket support was recently retired from the core
networking stack. As a follow-up of that, drop the connection tracker
and NAT support for UDP-Lite in Netfilter.

This patch removes CONFIG_NF_CT_PROTO_UDPLITE and scrubs UDP-Lite
awareness from the conntrack core, NAT core, nft_ct, and ctnetlink.
Please note that stateless packet inspection, matching, ipsets or
logging support for IPPROTO_UDPLITE is preserved.

As conntrack no longer extracts UDP-Lite ports or tracks its L4 state,
when performing NAT the UDP-Lite checksum cannot be updated anymore.
That is an expected and acceptable consequence of removing UDP-Lite
conntrack module.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:26 +02:00
Florian Westphal
542be3fa5a netfilter: xt_socket: enable defrag after all other checks
Originally this did not matter because defrag was enabled once per netns
and only disabled again on netns dismantle.  When this got changed I should
have adjusted checkentry to not leave defrag enabled on error.

Fixes: de8c12110a ("netfilter: disable defrag once its no longer needed")
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:26 +02:00
Marino Dzalto
24bd5c2679 netfilter: xt_HL: add pr_fmt and checkentry validation
Add pr_fmt to prefix log messages with the module name for
easier debugging in dmesg.

Add checkentry functions for IPv4 (ttl_mt_check) and IPv6
(hl_mt6_check) to validate the match mode at rule registration
time, rejecting invalid modes with -EINVAL.

The evaluation function returns false in case the mode is
unknown, so this is a cleanup, not a bug fix.

Signed-off-by: Marino Dzalto <marino.dzalto@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:26 +02:00
Florian Westphal
74feb7d373 netfilter: nfnetlink: prefer skb_mac_header helpers
This adds implicit DEBUG_WARN_ON_ONCE for debug configurations.
No other changes intended.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:26 +02:00
Florian Westphal
8df772afc9 netfilter: x_physdev: reject empty or not-nul terminated device names
Reject names that lack a \0 character and reject the empty string as
well. iptables allows this but it fails to re-parse iptables-save output
that contain such rules.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:26 +02:00
Julian Anastasov
8d7de5477e ipvs: add conn_lfactor and svc_lfactor sysctl vars
Allow the default load factor for the connection and service tables
to be configured.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:26 +02:00
Julian Anastasov
9a9ccef907 ipvs: add ip_vs_status info
Add /proc/net/ip_vs_status to show current state of IPVS.

The motivation for this new /proc interface is to provide the output
for the users to help them decide when to tune the load factor for
hash tables, which is possible with the new sysctl knobs coming in
followup patch.

The output also includes information for the kthreads used for stats.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:25 +02:00
Julian Anastasov
22e620fe84 ipvs: show the current conn_tab size to users
As conn_tab is per-net, better to show the current hash table size
to users instead of the ip_vs_conn_tab_size (max).

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-10 12:16:25 +02:00
Jakub Kicinski
b6e39e4846 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-7.0-rc8).

Conflicts:

net/ipv6/seg6_iptunnel.c
  c3812651b5 ("seg6: separate dst_cache for input and output paths in seg6 lwtunnel")
  78723a62b9 ("seg6: add per-route tunnel source address")
https://lore.kernel.org/adZhwtOYfo-0ImSa@sirena.org.uk

net/ipv4/icmp.c
  fde29fd934 ("ipv4: icmp: fix null-ptr-deref in icmp_build_probe()")
  d98adfbdd5 ("ipv4: drop ipv6_stub usage and use direct function calls")
https://lore.kernel.org/adO3dccqnr6j-BL9@sirena.org.uk

Adjacent changes:

drivers/net/ethernet/stmicro/stmmac/chain_mode.c
  51f4e090b9 ("net: stmmac: fix integer underflow in chain mode")
  6b4286e055 ("net: stmmac: rename STMMAC_GET_ENTRY() -> STMMAC_NEXT_ENTRY()")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-09 13:20:59 -07:00
Florian Westphal
936206e3f6 netfilter: nfnetlink_queue: make hash table per queue
Sharing a global hash table among all queues is tempting, but
it can cause crash:

BUG: KASAN: slab-use-after-free in nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue]
[..]
 nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue]
 nfnetlink_rcv_msg+0x46a/0x930
 kmem_cache_alloc_node_noprof+0x11e/0x450

struct nf_queue_entry is freed via kfree, but parallel cpu can still
encounter such an nf_queue_entry when walking the list.

Alternative fix is to free the nf_queue_entry via kfree_rcu() instead,
but as we have to alloc/free for each skb this will cause more mem
pressure.

Cc: Scott Mitchell <scott.k.mitch1@gmail.com>
Fixes: e19079adcd ("netfilter: nfnetlink_queue: optimize verdict lookup with hash table")
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 13:34:51 +02:00
Tuan Do
f8dca15a1b netfilter: nft_ct: fix use-after-free in timeout object destroy
nft_ct_timeout_obj_destroy() frees the timeout object with kfree()
immediately after nf_ct_untimeout(), without waiting for an RCU grace
period. Concurrent packet processing on other CPUs may still hold
RCU-protected references to the timeout object obtained via
rcu_dereference() in nf_ct_timeout_data().

Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer
freeing until after an RCU grace period, matching the approach already
used in nfnetlink_cttimeout.c.

KASAN report:
 BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0
 Read of size 4 at addr ffff8881035fe19c by task exploit/80

 Call Trace:
  nf_conntrack_tcp_packet+0x1381/0x29d0
  nf_conntrack_in+0x612/0x8b0
  nf_hook_slow+0x70/0x100
  __ip_local_out+0x1b2/0x210
  tcp_sendmsg_locked+0x722/0x1580
  __sys_sendto+0x2d8/0x320

 Allocated by task 75:
  nft_ct_timeout_obj_init+0xf6/0x290
  nft_obj_init+0x107/0x1b0
  nf_tables_newobj+0x680/0x9c0
  nfnetlink_rcv_batch+0xc29/0xe00

 Freed by task 26:
  nft_obj_destroy+0x3f/0xa0
  nf_tables_trans_destroy_work+0x51c/0x5c0
  process_one_work+0x2c4/0x5a0

Fixes: 7e0b2b57f0 ("netfilter: nft_ct: add ct timeout support")
Cc: stable@vger.kernel.org
Signed-off-by: Tuan Do <tuan@calif.io>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 13:34:16 +02:00
Ren Wei
ff64c5bfef netfilter: xt_multiport: validate range encoding in checkentry
ports_match_v1() treats any non-zero pflags entry as the start of a
port range and unconditionally consumes the next ports[] element as
the range end.

The checkentry path currently validates protocol, flags and count, but
it does not validate the range encoding itself. As a result, malformed
rules can mark the last slot as a range start or place two range starts
back to back, leaving ports_match_v1() to step past the last valid
ports[] element while interpreting the rule.

Reject malformed multiport v1 rules in checkentry by validating that
each range start has a following element and that the following element
is not itself marked as another range start.

Fixes: a89ecb6a2e ("[NETFILTER]: x_tables: unify IPv4/IPv6 multiport match")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Yuhang Zheng <z1652074432@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 13:33:38 +02:00
Xiang Mei
1f3083aec8 netfilter: nfnetlink_log: initialize nfgenmsg in NLMSG_DONE terminator
When batching multiple NFLOG messages (inst->qlen > 1), __nfulnl_send()
appends an NLMSG_DONE terminator with sizeof(struct nfgenmsg) payload via
nlmsg_put(), but never initializes the nfgenmsg bytes. The nlmsg_put()
helper only zeroes alignment padding after the payload, not the payload
itself, so four bytes of stale kernel heap data are leaked to userspace
in the NLMSG_DONE message body.

Use nfnl_msg_put() to build the NLMSG_DONE terminator, which initializes
the nfgenmsg payload via nfnl_fill_hdr(), consistent with how
__build_packet_message() already constructs NFULNL_MSG_PACKET headers.

Fixes: 29c5d4afba ("[NETFILTER]: nfnetlink_log: fix sending of multipart messages")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 13:33:36 +02:00
Weiming Shi
9a91797e61 ipvs: fix NULL deref in ip_vs_add_service error path
When ip_vs_bind_scheduler() succeeds in ip_vs_add_service(), the local
variable sched is set to NULL.  If ip_vs_start_estimator() subsequently
fails, the out_err cleanup calls ip_vs_unbind_scheduler(svc, sched)
with sched == NULL.  ip_vs_unbind_scheduler() passes the cur_sched NULL
check (because svc->scheduler was set by the successful bind) but then
dereferences the NULL sched parameter at sched->done_service, causing a
kernel panic at offset 0x30 from NULL.

 Oops: general protection fault, [..] [#1] PREEMPT SMP KASAN NOPTI
 KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
 RIP: 0010:ip_vs_unbind_scheduler (net/netfilter/ipvs/ip_vs_sched.c:69)
 Call Trace:
  <TASK>
  ip_vs_add_service.isra.0 (net/netfilter/ipvs/ip_vs_ctl.c:1500)
  do_ip_vs_set_ctl (net/netfilter/ipvs/ip_vs_ctl.c:2809)
  nf_setsockopt (net/netfilter/nf_sockopt.c:102)
  [..]

Fix by simply not clearing the local sched variable after a successful
bind.  ip_vs_unbind_scheduler() already detects whether a scheduler is
installed via svc->scheduler, and keeping sched non-NULL ensures the
error path passes the correct pointer to both ip_vs_unbind_scheduler()
and ip_vs_scheduler_put().

While the bug is older, the problem popups in more recent kernels (6.2),
when the new error path is taken after the ip_vs_start_estimator() call.

Fixes: 705dd34440 ("ipvs: use kthreads for stats estimation")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Acked-by: Simon Horman <horms@kernel.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 13:33:28 +02:00
Pablo Neira Ayuso
c6f8557758 netfilter: nf_tables_offload: add nft_flow_action_entry_next() and use it
Add a new helper function to retrieve the next action entry in flow
rule, check if the maximum number of actions is reached, bail out in
such case.

Replace existing opencoded iteration on the action array by this
helper function.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:31 +02:00
David Laight
f33fad8dbf netfilter: nf_conntrack_h323: Correct indentation when H323_TRACE defined
The trace lines are indented using PRINT("%*.s", xx, " ").
Userspace will treat this as "%*.0s" and will output no characters
when 'xx' is zero, the kernel treats it as "%*s" and will output
a single ' ' - which is probably what is intended.

Change all the formats to "%*s" removing the default precision.
This gives a single space indent when level is zero.

Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:31 +02:00
Pablo Neira Ayuso
3785091c6c netfilter: nft_meta: add double-tagged vlan and pppoe support
Currently:

  add rule netdev x y ip saddr 1.1.1.1

does not work with neither double-tagged vlan nor pppoe packets. This is
because the network and transport header offset are not pointing to the
IP and transport protocol headers in the stack.

This patch expands NFT_META_PROTOCOL and NFT_META_L4PROTO to parse
double-tagged vlan and pppoe packets so matching network and transport
header fields becomes possible with the existing userspace generated
bytecode. Note that this parser only supports double-tagged vlan which
is composed of vlan offload + vlan header in the skb payload area for
simplicity.

NFT_META_PROTOCOL is used by bridge and netdev family as an implicit
dependency in the bytecode to match on network header fields.
Similarly, there is also NFT_META_L4PROTO, which is also used as an
implicit dependency when matching on the transport protocol header
fields.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:31 +02:00
Florian Westphal
a3f1e6a19a netfilter: nft_set_pipapo_avx2: remove redundant loop in lookup_slow
nft_pipapo_avx2_lookup_slow will never be used in reality, because the
common sizes are handled by avx2 optimized versions.

However, nft_pipapo_avx2_lookup_slow loops over the data just like the
avx2 functions.  However, _slow doesn't need to do that.

As-is, first loop sets all the right result bits and the next iterations
boil down to 'x = x & x'.  Remove the loop.

Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:31 +02:00
Florian Westphal
04e1ca21a5 netfilter: nft_set_pipapo: increment data in one step
Since commit e807b13cb3 ("nft_set_pipapo: Generalise group size for buckets")
there is no longer a need to increment the data pointer in two steps.
Switch to a single invocation of NFT_PIPAPO_GROUPS_PADDED_SIZE() helper,
like the avx2 implementation.

[ Stefano: Improve commit message ]

Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:31 +02:00
Florian Westphal
8e57338c36 netfilter: nf_tables: add netlink policy based cap on registers
Should have no effect in practice; all of these use the
nft_parse_register_load/store apis which is mandatory anyway due
to the need to further validate the register load/store, e.g.
that the size argument doesn't result in out-of-bounds load/store.

OTOH this is a simple method to reject obviously wrong input
at earlier stage.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:31 +02:00
Florian Westphal
66b75e6bbe netfilter: add more netlink-based policy range checks
These spots either already check the attribute range manually
before use or the consuming functions tolerate unexpected values.

Nevertheless, add more range checks via netlink policy so we gain
more users and avoid possible re-use in other places that might
not have the required manual checks.  This also improves error
reporting: netlink core can generate extack errors.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:30 +02:00
Florian Westphal
390a57dd61 netfilter: nf_conntrack_h323: remove unreliable debug code in decode_octstr
The debug code (not enabled in any build) reads up to 6 octets of
the inpt buffer, but does so without bound checks.  Zap this.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:27 +02:00
Florian Westphal
606bd17ef0 netfilter: add deprecation warning for dccp support
Add a deprecation warning for the xt_dccp match and the
nft exthdr code.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:27 +02:00
Florian Westphal
7970d6aaf7 netfilter: nf_conntrack_sip: remove net variable shadowing
net is already set, derived from nf_conn.
I don't see how the device could be living in a different netns
than the conntrack entry.

Remove the extra variable and re-use existing one.

Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:27 +02:00
Sun Jian
6e6f2b9b33 netfilter: use function typedefs for __rcu NAT helper hook pointers
After commit 07919126ec ("netfilter: annotate NAT helper hook pointers
with __rcu"), sparse can warn about type/address-space mismatches when
RCU-dereferencing NAT helper hook function pointers.

The hooks are __rcu-annotated and accessed via rcu_dereference(), but the
combination of complex function pointer declarators and the WRITE_ONCE()
machinery used by RCU_INIT_POINTER()/rcu_assign_pointer() can confuse
sparse and trigger false positives.

Introduce typedefs for the NAT helper function types, so __rcu applies to
a simple "fn_t __rcu *" pointer form. Also replace local typeof(hook)
variables with "fn_t *" to avoid propagating __rcu address space into
temporaries.

No functional change intended.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603022359.3dGE9fwI-lkp@intel.com/
Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-04-08 07:51:26 +02:00
Jakub Kicinski
8ffb33d770 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-7.0-rc7).

Conflicts:

net/vmw_vsock/af_vsock.c
  b18c833888 ("vsock: initialize child_ns_mode_locked in vsock_net_init()")
  0de607dc4f ("vsock: add G2H fallback for CIDs not owned by H2G transport")

Adjacent changes:

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
  ceee35e567 ("bnxt_en: Refactor some basic ring setup and adjustment logic")
  57cdfe0dc7 ("bnxt_en: Resize RSS contexts on channel count change")

drivers/net/wireless/intel/iwlwifi/mld/mac80211.c
  4d56037a02 ("wifi: iwlwifi: mld: block EMLSR during TDLS connections")
  687a95d204 ("wifi: iwlwifi: mld: correctly set wifi generation data")

drivers/net/wireless/intel/iwlwifi/mld/scan.h
  b6045c899e ("wifi: iwlwifi: mld: Refactor scan command handling")
  ec66ec6a5a ("wifi: iwlwifi: mld: Fix MLO scan timing")

drivers/net/wireless/intel/iwlwifi/mvm/fw.c
  078df640ef ("wifi: iwlwifi: mld: add support for iwl_mcc_allowed_ap_type_cmd v
2")
  323156c354 ("wifi: iwlwifi: mvm: don't send a 6E related command when not supported")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-02 11:03:13 -07:00
Pablo Neira Ayuso
da107398cb netfilter: nf_tables: reject immediate NF_QUEUE verdict
nft_queue is always used from userspace nftables to deliver the NF_QUEUE
verdict. Immediately emitting an NF_QUEUE verdict is never used by the
userspace nft tools, so reject immediate NF_QUEUE verdicts.

The arp family does not provide queue support, but such an immediate
verdict is still reachable. Globally reject NF_QUEUE immediate verdicts
to address this issue.

Fixes: f342de4e2f ("netfilter: nf_tables: reject QUEUE/DROP verdict parameters")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:30 +02:00
Pablo Neira Ayuso
3d5d488f11 netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP
Weiming Shi says:

xt_match and xt_target structs registered with NFPROTO_UNSPEC can be
loaded by any protocol family through nft_compat. When such a
match/target sets .hooks to restrict which hooks it may run on, the
bitmask uses NF_INET_* constants. This is only correct for families
whose hook layout matches NF_INET_*: IPv4, IPv6, INET, and bridge
all share the same five hooks (PRE_ROUTING ... POST_ROUTING).

ARP only has three hooks (IN=0, OUT=1, FORWARD=2) with different
semantics. Because NF_ARP_OUT == 1 == NF_INET_LOCAL_IN, the .hooks
validation silently passes for the wrong reasons, allowing matches to
run on ARP chains where the hook assumptions (e.g. state->in being
set on input hooks) do not hold. This leads to NULL pointer
dereferences; xt_devgroup is one concrete example:

 Oops: general protection fault, probably for non-canonical address 0xdffffc0000000044: 0000 [#1] SMP KASAN NOPTI
 KASAN: null-ptr-deref in range [0x0000000000000220-0x0000000000000227]
 RIP: 0010:devgroup_mt+0xff/0x350
 Call Trace:
  <TASK>
  nft_match_eval (net/netfilter/nft_compat.c:407)
  nft_do_chain (net/netfilter/nf_tables_core.c:285)
  nft_do_chain_arp (net/netfilter/nft_chain_filter.c:61)
  nf_hook_slow (net/netfilter/core.c:623)
  arp_xmit (net/ipv4/arp.c:666)
  </TASK>
 Kernel panic - not syncing: Fatal exception in interrupt

Fix it by restricting arptables to NFPROTO_ARP extensions only.
Note that arptables-legacy only supports:

- arpt_CLASSIFY
- arpt_mangle
- arpt_MARK

that provide explicit NFPROTO_ARP match/target declarations.

Fixes: 9291747f11 ("netfilter: xtables: add device group match")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Yifan Wu
9862ef9ab0 netfilter: ipset: drop logically empty buckets in mtype_del
mtype_del() counts empty slots below n->pos in k, but it only drops the
bucket when both n->pos and k are zero. This misses buckets whose live
entries have all been removed while n->pos still points past deleted slots.

Treat a bucket as empty when all positions below n->pos are unused and
release it directly instead of shrinking it further.

Fixes: 8af1c6fbd9 ("netfilter: ipset: Fix forceadd evaluation path")
Cc: stable@vger.kernel.org
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <dstsmallbird@foxmail.com>
Signed-off-by: Yifan Wu <yifanwucs@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Reviewed-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Pablo Neira Ayuso
917b61fa20 netfilter: ctnetlink: ignore explicit helper on new expectations
Use the existing master conntrack helper, anything else is not really
supported and it just makes validation more complicated, so just ignore
what helper userspace suggests for this expectation.

This was uncovered when validating CTA_EXPECT_CLASS via different helper
provided by userspace than the existing master conntrack helper:

  BUG: KASAN: slab-out-of-bounds in nf_ct_expect_related_report+0x2479/0x27c0
  Read of size 4 at addr ffff8880043fe408 by task poc/102
  Call Trace:
   nf_ct_expect_related_report+0x2479/0x27c0
   ctnetlink_create_expect+0x22b/0x3b0
   ctnetlink_new_expect+0x4bd/0x5c0
   nfnetlink_rcv_msg+0x67a/0x950
   netlink_rcv_skb+0x120/0x350

Allowing to read kernel memory bytes off the expectation boundary.

CTA_EXPECT_HELP_NAME is still used to offer the helper name to userspace
via netlink dump.

Fixes: bd07793705 ("netfilter: nfnetlink_queue: allow to attach expectations to conntracks")
Reported-by: Qi Tang <tpluszz77@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Qi Tang
35177c6877 netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent
ctnetlink_alloc_expect() allocates expectations from a non-zeroing
slab cache via nf_ct_expect_alloc().  When CTA_EXPECT_NAT is not
present in the netlink message, saved_addr and saved_proto are
never initialized.  Stale data from a previous slab occupant can
then be dumped to userspace by ctnetlink_exp_dump_expect(), which
checks these fields to decide whether to emit CTA_EXPECT_NAT.

The safe sibling nf_ct_expect_init(), used by the packet path,
explicitly zeroes these fields.

Zero saved_addr, saved_proto and dir in the else branch, guarded
by IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when
NAT is enabled.

Confirmed by priming the expect slab with NAT-bearing expectations,
freeing them, creating a new expectation without CTA_EXPECT_NAT,
and observing that the ctnetlink dump emits a spurious
CTA_EXPECT_NAT containing stale data from the prior allocation.

Fixes: 076a0ca026 ("netfilter: ctnetlink: add NAT support for expectations")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Qi Tang <tpluszz77@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Qi Tang
a242a9ae58 netfilter: nf_conntrack_helper: pass helper to expect cleanup
nf_conntrack_helper_unregister() calls nf_ct_expect_iterate_destroy()
to remove expectations belonging to the helper being unregistered.
However, it passes NULL instead of the helper pointer as the data
argument, so expect_iter_me() never matches any expectation and all
of them survive the cleanup.

After unregister returns, nfnl_cthelper_del() frees the helper
object immediately.  Subsequent expectation dumps or packet-driven
init_conntrack() calls then dereference the freed exp->helper,
causing a use-after-free.

Pass the actual helper pointer so expectations referencing it are
properly destroyed before the helper object is freed.

  BUG: KASAN: slab-use-after-free in string+0x38f/0x430
  Read of size 1 at addr ffff888003b14d20 by task poc/103
  Call Trace:
   string+0x38f/0x430
   vsnprintf+0x3cc/0x1170
   seq_printf+0x17a/0x240
   exp_seq_show+0x2e5/0x560
   seq_read_iter+0x419/0x1280
   proc_reg_read+0x1ac/0x270
   vfs_read+0x179/0x930
   ksys_read+0xef/0x1c0
  Freed by task 103:
  The buggy address is located 32 bytes inside of
   freed 192-byte region [ffff888003b14d00, ffff888003b14dc0)

Fixes: ac7b848390 ("netfilter: expect: add and use nf_ct_expect_iterate helpers")
Signed-off-by: Qi Tang <tpluszz77@gmail.com>
Reviewed-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Florian Westphal
b7e8590987 netfilter: ipset: use nla_strcmp for IPSET_ATTR_NAME attr
IPSET_ATTR_NAME and IPSET_ATTR_NAMEREF are of NLA_STRING type, they
cannot be treated like a c-string.

They either have to be switched to NLA_NUL_STRING, or the compare
operations need to use the nla functions.

Fixes: f830837f0e ("netfilter: ipset: list:set set type support")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Florian Westphal
a958a4f90d netfilter: x_tables: ensure names are nul-terminated
Reject names that lack a \0 character before feeding them
to functions that expect c-strings.

Fixes tag is the most recent commit that needs this change.

Fixes: c38c4597e4 ("netfilter: implement xt_cgroup cgroup2 path match")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Florian Westphal
6d52a4a052 netfilter: nfnetlink_log: account for netlink header size
This is a followup to an old bug fix: NLMSG_DONE needs to account
for the netlink header size, not just the attribute size.

This can result in a WARN splat + drop of the netlink message,
but other than this there are no ill effects.

Fixes: 9dfa1dfe4d ("netfilter: nf_log: account for size of NLMSG_DONE attribute")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:55:29 +02:00
Pablo Neira Ayuso
76522fcdbc netfilter: flowtable: strictly check for maximum number of actions
The maximum number of flowtable hardware offload actions in IPv6 is:

* ethernet mangling (4 payload actions, 2 for each ethernet address)
* SNAT (4 payload actions)
* DNAT (4 payload actions)
* Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing)
  for QinQ.
* Redirect (1 action)

Which makes 17, while the maximum is 16. But act_ct supports for tunnels
actions too. Note that payload action operates at 32-bit word level, so
mangling an IPv6 address takes 4 payload actions.

Update flow_action_entry_next() calls to check for the maximum number of
supported actions.

While at it, rise the maximum number of actions per flow from 16 to 24
so this works fine with IPv6 setups.

Fixes: c29f74e0df ("netfilter: nf_flow_table: hardware offload support")
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-04-01 11:50:14 +02:00
Fernando Fernandez Mancera
b2c981e7c4 netfilter: remove nf_ipv6_ops and use direct function calls
As IPv6 is built-in only, nf_ipv6_ops can be removed completely as it is
not longer necessary.

Convert all nf_ipv6_ops usage to direct function calls instead. In
addition, remove the ipv6_netfilter_init/fini() functions as they are
not necessary any longer.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Tested-by: Ricardo B. Marlière <rbm@suse.com>
Link: https://patch.msgid.link/20260325120928.15848-12-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-29 11:21:24 -07:00
Fernando Fernandez Mancera
309b905dee ipv6: convert CONFIG_IPV6 to built-in only and clean up Kconfigs
Maintaining a modular IPv6 stack offers image size savings for specific
setups, this benefit is outweighed by the architectural burden it
imposes on the subsystems on implementation and maintenance. Therefore,
drop it.

Change CONFIG_IPV6 from tristate to bool. Remove all Kconfig
dependencies across the tree that explicitly checked for IPV6=m. In
addition, remove MODULE_DESCRIPTION(), MODULE_ALIAS(), MODULE_AUTHOR()
and MODULE_LICENSE().

This is also replacing module_init() by device_initcall(). It is not
possible to use fs_initcall() as IPv4 does because that creates a race
condition on IPv6 addrconf.

Finally, modify the default configs from CONFIG_IPV6=m to CONFIG_IPV6=y
except for m68k as according to the bloat-o-meter the image is
increasing by 330KB~ and that isn't acceptable. Instead, disable IPv6 on
this architecture by default. This is aligned with m68k RAM requirements
and recommendations [1].

[1] http://www.linux-m68k.org/faq/ram.html

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Tested-by: Ricardo B. Marlière <rbm@suse.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # arm64
Link: https://patch.msgid.link/20260325120928.15848-2-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-29 11:21:22 -07:00
Jakub Kicinski
9ebcf66cd6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-7.0-rc6).

No conflicts, or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-26 12:09:57 -07:00
David Carlier
8f15b5071b netfilter: ctnetlink: use netlink policy range checks
Replace manual range and mask validations with netlink policy
annotations in ctnetlink code paths, so that the netlink core rejects
invalid values early and can generate extack errors.

- CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at
  policy level, removing the manual >= TCP_CONNTRACK_MAX check.
- CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE
  (14). The normal TCP option parsing path already clamps to this value,
  but the ctnetlink path accepted 0-255, causing undefined behavior when
  used as a u32 shift count.
- CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with
  CTA_FILTER_F_ALL, removing the manual mask checks.
- CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding
  a new mask define grouping all valid expect flags.

Extracted from a broader nf-next patch by Florian Westphal, scoped to
ctnetlink for the fixes tree.

Fixes: c8e2078cfe ("[NETFILTER]: ctnetlink: add support for internal tcp connection tracking flags handling")
Signed-off-by: David Carlier <devnexen@gmail.com>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:28:17 +01:00
Weiming Shi
6a2b724460 netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp
process_sdp() declares union nf_inet_addr rtp_addr on the stack and
passes it to the nf_nat_sip sdp_session hook after walking the SDP
media descriptions. However rtp_addr is only initialized inside the
media loop when a recognized media type with a non-zero port is found.

If the SDP body contains no m= lines, only inactive media sections
(m=audio 0 ...) or only unrecognized media types, rtp_addr is never
assigned. Despite that, the function still calls hooks->sdp_session()
with &rtp_addr, causing nf_nat_sdp_session() to format the stale stack
value as an IP address and rewrite the SDP session owner and connection
lines with it.

With CONFIG_INIT_STACK_ALL_ZERO (default on most distributions) this
results in the session-level o= and c= addresses being rewritten to
0.0.0.0 for inactive SDP sessions. Without stack auto-init the
rewritten address is whatever happened to be on the stack.

Fix this by pre-initializing rtp_addr from the session-level connection
address (caddr) when available, and tracking via a have_rtp_addr flag
whether any valid address was established. Skip the sdp_session hook
entirely when no valid address exists.

Fixes: 4ab9e64e5e ("[NETFILTER]: nf_nat_sip: split up SDP mangling")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:28:17 +01:00
Pablo Neira Ayuso
3db5647984 netfilter: nf_conntrack_expect: skip expectations in other netns via proc
Skip expectations that do not reside in this netns.

Similar to e77e6ff502 ("netfilter: conntrack: do not dump other netns's
conntrack entries via proc").

Fixes: 9b03f38d04 ("netfilter: netns nf_conntrack: per-netns expectations")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:28:03 +01:00
Pablo Neira Ayuso
02a3231b6d netfilter: nf_conntrack_expect: store netns and zone in expectation
__nf_ct_expect_find() and nf_ct_expect_find_get() are called under
rcu_read_lock() but they dereference the master conntrack via
exp->master.

Since the expectation does not hold a reference on the master conntrack,
this could be dying conntrack or different recycled conntrack than the
real master due to SLAB_TYPESAFE_RCU.

Store the netns, the master_tuple and the zone in struct
nf_conntrack_expect as a safety measure.

This patch is required by the follow up fix not to dump expectations
that do not belong to this netns.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:24:40 +01:00
Pablo Neira Ayuso
bffcaad9af netfilter: ctnetlink: ensure safe access to master conntrack
Holding reference on the expectation is not sufficient, the master
conntrack object can just go away, making exp->master invalid.

To access exp->master safely:

- Grab the nf_conntrack_expect_lock, this gets serialized with
  clean_from_lists() which also holds this lock when the master
  conntrack goes away.

- Hold reference on master conntrack via nf_conntrack_find_get().
  Not so easy since the master tuple to look up for the master conntrack
  is not available in the existing problematic paths.

This patch goes for extending the nf_conntrack_expect_lock section
to address this issue for simplicity, in the cases that are described
below this is just slightly extending the lock section.

The add expectation command already holds a reference to the master
conntrack from ctnetlink_create_expect().

However, the delete expectation command needs to grab the spinlock
before looking up for the expectation. Expand the existing spinlock
section to address this to cover the expectation lookup. Note that,
the nf_ct_expect_iterate_net() calls already grabs the spinlock while
iterating over the expectation table, which is correct.

The get expectation command needs to grab the spinlock to ensure master
conntrack does not go away. This also expands the existing spinlock
section to cover the expectation lookup too. I needed to move the
netlink skb allocation out of the spinlock to keep it GFP_KERNEL.

For the expectation events, the IPEXP_DESTROY event is already delivered
under the spinlock, just move the delivery of IPEXP_NEW under the
spinlock too because the master conntrack event cache is reached through
exp->master.

While at it, add lockdep notations to help identify what codepaths need
to grab the spinlock.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:18:32 +01:00
Pablo Neira Ayuso
f017941060 netfilter: nf_conntrack_expect: use expect->helper
Use expect->helper in ctnetlink and /proc to dump the helper name.
Using nfct_help() without holding a reference to the master conntrack
is unsafe.

Use exp->master->helper in ctnetlink path if userspace does not provide
an explicit helper when creating an expectation to retain the existing
behaviour. The ctnetlink expectation path holds the reference on the
master conntrack and nf_conntrack_expect lock and the nfnetlink glue
path refers to the master ct that is attached to the skb.

Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:18:31 +01:00
Pablo Neira Ayuso
9c42bc9db9 netfilter: nf_conntrack_expect: honor expectation helper field
The expectation helper field is mostly unused. As a result, the
netfilter codebase relies on accessing the helper through exp->master.

Always set on the expectation helper field so it can be used to reach
the helper.

nf_ct_expect_init() is called from packet path where the skb owns
the ct object, therefore accessing exp->master for the newly created
expectation is safe. This saves a lot of updates in all callsites
to pass the ct object as parameter to nf_ct_expect_init().

This is a preparation patches for follow up fixes.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:18:31 +01:00
Pablo Neira Ayuso
fafdd92b9e netfilter: nft_set_rbtree: revisit array resize logic
Chris Arges reports high memory consumption with thousands of
containers, this patch revisits the array allocation logic.

For anonymous sets, start by 16 slots (which takes 256 bytes on x86_64).
Expand it by x2 until threshold of 512 slots is reached, over that
threshold, expand it by x1.5.

For non-anonymous set, start by 1024 slots in the array (which takes 16
Kbytes initially on x86_64). Expand it by x1.5.

Use set->ndeact to subtract deactivated elements when calculating the
number of the slots in the array, otherwise the array size array gets
increased artifically. Add special case shrink logic to deal with flush
set too.

The shrink logic is skipped by anonymous sets.

Use check_add_overflow() to calculate the new array size.

Add a WARN_ON_ONCE check to make sure elements fit into the new array
size.

Reported-by: Chris Arges <carges@cloudflare.com>
Fixes: 7e43e0a114 ("netfilter: nft_set_rbtree: translate rbtree to array for binary search")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-03-26 13:18:31 +01:00