linux-stable.git/net/netfilter, branch v7.1.4

netfilter: flowtable: IPIP tunnel hardware offload is not yet support

2026-07-18T14:55:29+00:00

commit 6c5dcab95f4cd42a1648739ec9300fbb4b1a021f upstream.

No driver supports for IPIP tunnels yet, give up early on setting up the
hardware offload for this scenario.

This patch adds a stub that can be enhanced to add more configuration
that are currently not supported. As of now, the offload work is
enqueued to the worker, then ignored if the hardware offload
configuration is not supported.

Check the NF_FLOW_HW flag to know if this entry was already tried once
to be offloaded so this is not retried on refresh when unsupported. Move
NF_FLOW_HW flag check to nf_flow_offload_add(). If this NF_FLOW_HW flag
is unset the _del and _stats variants are never called.

This can be updated later on to skip hardware offload work to be queued
in case hardware offload does not support it.

Fixes: d98103575dcd ("netfilter: flowtable: Add IP6IP6 rx sw acceleration")
Fixes: ab427db17885 ("netfilter: flowtable: Add IPIP rx sw acceleration")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan 
Reported-by: Xin Liu 
Reported-by: Zhengyang Chen 
Signed-off-by: Pablo Neira Ayuso 
Acked-by: Lorenzo Bianconi 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: flowtable: fix offloaded ct timeout never being extended

2026-07-18T14:55:28+00:00

commit 53b3e60edb674b442b2b3bbdba484667b0f47a5d upstream.

OpenWrt has recently migrated many platforms to kernel 6.18. On the
MediaTek platform, which supports hardware network offloading, WiFi
connections accelerated via the WED path were observed to drop after
roughly 300 seconds.

After several debugging sessions, assisted by the Claude LLM, the
problem was narrowed down as follows:

nf_flow_table_extend_ct_timeout() extends ct->timeout for offloaded
flows using:

	cmpxchg(&ct->timeout, expires, new_timeout);

'expires' comes from nf_ct_expires(ct) and is a relative value, while
ct->timeout holds an absolute timestamp. The two are never equal, so
the cmpxchg always fails and the timeout is never extended.

This goes unnoticed for most flows, but a long-lived hardware (WED)
offloaded flow on MediaTek MT7986 eventually has ct->timeout decay to
zero, the conntrack entry is reaped and the connection breaks.

Open-code the relative value from a single READ_ONCE(ct->timeout)
snapshot and compare against that same absolute snapshot in the
cmpxchg, so the timeout extension actually takes effect while the
datapath remains authoritative if it updates ct->timeout concurrently.

Fixes: 03428ca5cee9 ("netfilter: conntrack: rework offload nf_conn timeout extension logic")
Cc: stable@vger.kernel.org
Suggested-by: Florian Westphal 
Signed-off-by: Adrian Bente 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: handle unreadable frags

2026-07-18T14:55:28+00:00

commit da5b58478a9c1b85608c9e40a3b8432d071b409e upstream.

sashiko reports:
 When an skb with unreadable fragments (such as from devmem TCP, where
 skb_frags_readable(skb) returns false) is processed by the u32 module,
 skb_copy_bits() will safely return a negative error code [..]

xt_u32: bail out with hotdrop in this case.
gather_frags: return -1, just as if we had no fragment header.
nfnetlink_queue: restrict to the linear part.
nfnetlink_log: restrict to the linear part.

v2:
 - skb_zerocopy helpers don't copy readable flag, i.e. nfnetlink_queue
 is broken too
 xt_u32 shouldn't return true if hotdrop was set.

Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags")
Cc: stable@vger.kernel.org
Acked-by: Mina Almasry 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: ctnetlink: use nf_ct_exp_net() in expectation dump

2026-07-18T14:55:28+00:00

commit a7f57320bbbc67e347bf5fff4b4a9bab980d5956 upstream.

Commit 02a3231b6d82 ("netfilter: nf_conntrack_expect: store netns and zone in expectation")
introduced exp->net so RCU-only expectation paths no longer need to
dereference exp->master for netns lookups.

Commit 3db5647984de ("netfilter: nf_conntrack_expect: skip expectations in other netns via proc")
updated the proc path accordingly, but ctnetlink_exp_dump_table() still
compares against nf_ct_net(exp->master).

Use nf_ct_exp_net(exp) here as well so the netlink dump path matches
the rest of the March 2026 expectation netns/RCU cleanup.

Fixes: 02a3231b6d82 ("netfilter: nf_conntrack_expect: store netns and zone in expectation")
Cc: stable@vger.kernel.org
Signed-off-by: Pratham Gupta 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: ipset: fix race between dump and ip_set_list resize

2026-07-18T14:55:24+00:00

commit 7cd9103283b26b917360ec99d7d2f2d761bcf1ab upstream.

The release path of ip_set_dump_do() and ip_set_dump_done() read
inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw()
of the array pointer. These run from netlink_recvmsg() without the nfnl
mutex and without an RCU read-side critical section.

A concurrent ip_set_create() can grow the array: it publishes the new
array, calls synchronize_net() and then kvfree()s the old one. Since the
dump paths read the array outside any RCU reader, synchronize_net() does
not wait for them and the old array can be freed while they still index
into it, causing a use-after-free.

The dumped set itself stays pinned via set->ref_netlink, so only the
array load needs protecting. Take rcu_read_lock() around it, matching
ip_set_get_byname() and __ip_set_put_byindex().

  BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
  Read of size 8 at addr ffff88800b5c4018 by task exploit/150
  Call Trace:
   ...
   kasan_report (mm/kasan/report.c:595)
   ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
   netlink_dump (net/netlink/af_netlink.c:2325)
   netlink_recvmsg (net/netlink/af_netlink.c:1976)
   sock_recvmsg (net/socket.c:1159)
   __sys_recvfrom (net/socket.c:2315)
   ...
  Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI
  KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7]
  RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698)
  Kernel panic - not syncing: Fatal exception

Fixes: 8a02bdd50b2e ("netfilter: ipset: Fix calling ip_set() macro at dumping")
Cc: stable@vger.kernel.org
Reported-by: Weiming Shi 
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei 
Acked-by: Jozsef Kadlecsik 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: nft_fib: fix stale stack leak via the OIFNAME register

2026-06-10T16:00:19+00:00

For NFT_FIB_RESULT_OIFNAME the destination register is declared with
len = IFNAMSIZ (four 32-bit registers), but on the lookup-fail,
RTN_LOCAL and oif-mismatch paths nft_fib{4,6}_eval() only writes one
register via "*dest = 0". The remaining three registers are left as
whatever was on the stack in nft_do_chain()'s struct nft_regs, and a
downstream expression that loads the register span can leak that
uninitialised kernel stack to userspace.

The NFTA_FIB_F_PRESENT existence check has the same shape: it is only
meaningful for NFT_FIB_RESULT_OIF, yet it was accepted for any result type
while the eval stores a single byte via nft_reg_store8(), leaving the rest
of the declared span stale.

Fix both:

 - replace the bare "*dest = 0" in the eval with nft_fib_store_result(),
   which strscpy_pad()s the whole IFNAMSIZ for OIFNAME (and is already
   used on the other early-return path), and

 - restrict NFTA_FIB_F_PRESENT to NFT_FIB_RESULT_OIF and declare its
   destination as a single u8, so the marked span matches the one byte
   the eval writes.

Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression")
Suggested-by: Florian Westphal 
Cc: stable@vger.kernel.org
Signed-off-by: Davide Ornaghi 
Signed-off-by: Pablo Neira Ayuso

netfilter: nft_exthdr: fix register tracking for F_PRESENT flag

2026-06-10T16:00:12+00:00

nft_exthdr_init() passes user-controlled priv->len to
nft_parse_register_store(), which marks that many bytes in the
register bitmap as initialized.  However, when NFT_EXTHDR_F_PRESENT
is set, the eval paths write only 1 byte (nft_reg_store8) or
4 bytes (*dest = 0 on TCP/DCCP error path).  When len > 4,
registers beyond the first are never written, retaining
uninitialized stack data from nft_regs.

Bail out if userspace requests too much data when F_PRESENT is set.

Reported-by: Ji'an Zhou 
Fixes: c078ca3b0c5b ("netfilter: nft_exthdr: Add support for existence check")
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_log: validate MAC header was set before dumping it

2026-06-10T16:00:01+00:00

The fallback path of dump_mac_header() guards the MAC header access
only with "skb->mac_header != skb->network_header", without checking
skb_mac_header_was_set(). When the MAC header is unset, mac_header is
0xffff, so the test passes and skb_mac_header(skb) returns
skb->head + 0xffff, ~64 KiB past the buffer; the loop then reads
dev->hard_header_len bytes out of bounds into the kernel log.

This is reachable via the netdev logger: nf_log_unknown_packet() calls
dump_mac_header() unconditionally, and an skb sent through AF_PACKET
with PACKET_QDISC_BYPASS reaches the egress hook with mac_header still
unset (__dev_queue_xmit(), which would reset it, is bypassed).

Add the skb_mac_header_was_set() check the ARPHRD_ETHER path already
uses, and replace the open-coded MAC header length test with
skb_mac_header_len(). Only skbs with an unset MAC header are affected;
valid ones are dumped as before.

 BUG: KASAN: slab-out-of-bounds in dump_mac_header (net/netfilter/nf_log_syslog.c:831)
 Read of size 1 at addr ffff88800ea49d3f by task exploit/148
 Call Trace:
  kasan_report (mm/kasan/report.c:595)
  dump_mac_header (net/netfilter/nf_log_syslog.c:831)
  nf_log_netdev_packet (net/netfilter/nf_log_syslog.c:938 net/netfilter/nf_log_syslog.c:963)
  nf_log_packet (net/netfilter/nf_log.c:260)
  nft_log_eval (net/netfilter/nft_log.c:60)
  nft_do_chain (net/netfilter/nf_tables_core.c:285)
  nft_do_chain_netdev (net/netfilter/nft_chain_filter.c:307)
  nf_hook_slow (net/netfilter/core.c:619)
  nf_hook_direct_egress (net/packet/af_packet.c:257)
  packet_xmit (net/packet/af_packet.c:280)
  packet_sendmsg (net/packet/af_packet.c:3114)
  __sys_sendto (net/socket.c:2265)

Fixes: 7eb9282cd0ef ("netfilter: ipt_LOG/ip6t_LOG: add option to print decoded MAC header")
Reported-by: Weiming Shi 
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_conntrack: destroy stale expectfn expectations on unregister

2026-06-10T15:58:39+00:00

NAT helpers such as nf_nat_h323 store a raw pointer to module text in
exp->expectfn (e.g. ip_nat_q931_expect). nf_ct_helper_expectfn_unregister()
only unlinks the callback descriptor and never walks the expectation table,
so an expectation pending at module removal survives with a dangling
exp->expectfn into freed module text.

When the expected connection arrives, init_conntrack() invokes
exp->expectfn(), now a stale pointer into the unloaded module. Reproduced
on a KASAN build by loading the H.323 helpers, creating a Q.931
expectation, unloading nf_nat_h323, then connecting to the expected port:

 Oops: int3: 0000 [#1] SMP KASAN NOPTI
 RIP: 0010:0xffffffffa06102d1
  init_conntrack.isra.0 (net/netfilter/nf_conntrack_core.c:1862)
  nf_conntrack_in (net/netfilter/nf_conntrack_core.c:2049)
  ipv4_conntrack_local (net/netfilter/nf_conntrack_proto.c:223)
  nf_hook_slow (net/netfilter/core.c:619)
  __ip_local_out (net/ipv4/ip_output.c:120)
  __tcp_transmit_skb (net/ipv4/tcp_output.c:1715)
  tcp_connect (net/ipv4/tcp_output.c:4374)
  tcp_v4_connect (net/ipv4/tcp_ipv4.c:345)
  __sys_connect (net/socket.c:2167)
 Modules linked in: nf_conntrack_h323 [last unloaded: nf_nat_h323]

Reaching the dangling state requires CAP_SYS_MODULE in the initial user
namespace to remove a NAT helper that still has live expectations, so this
is a robustness fix; leaving an expectation pointing at freed text is wrong
regardless.

Add nf_ct_helper_expectfn_destroy(), which walks the expectation table and
drops every expectation whose ->expectfn matches the descriptor being torn
down. Call it from each NAT helper's exit path after the existing RCU grace
period, so no expectation outlives the code it points at and no extra
synchronize_rcu() is introduced. With the fix, the same reproducer runs to
completion without the Oops.

Fixes: f587de0e2feb ("[NETFILTER]: nf_conntrack/nf_nat: add H.323 helper port")
Reported-by: Xiang Mei 
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_tables_offload: drop device refcount on error

2026-06-10T15:58:29+00:00

Reported by sashiko:
If nft_flow_action_entry_next() returns NULL, dev reference leaks.

Fixes: c6f85577584b ("netfilter: nf_tables_offload: add nft_flow_action_entry_next() and use it")
Reported-by: Juri Lelli 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso