Commit Graph

7446 Commits

Author SHA1 Message Date
Linus Torvalds
a13307e97d Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Pull BPF fixes from Daniel Borkmann:

 - Fix BPF verifier to preserve full pointer state for commuted
   scalar += pointer arithmetic (Yiyang Chen, Eduard Zingerman)

 - Fix a use-after-free of request sockets in the BPF TCP iterator
   batching (Jose Fernandez)

 - Fix a use-after-free of sk_redir in the BPF sockmap send verdict
   path (Chengfeng Ye)

 - Fix a netns reference imbalance in the BPF conntrack kfuncs
   (Chengfeng Ye)

 - Fix bpf_get_fsverity_digest() dynptr assumptions and silent
   digest truncation (Eric Biggers)

 - Fix bpf_tcp_{gen,check}_syncookie to check sk_state before
   sk_protocol to make sure it is a full socket (Luxiao Xu)

 - Fix rqspinlock to reset the tail when preserving the queue
   on deadlock (Kumar Kartikeya Dwivedi)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  rqspinlock: Reset tail when preserving queue on deadlock
  bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie
  fsverity: Fix silent truncation in bpf_get_fsverity_digest()
  fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions
  bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()
  bpf: Fix netns reference imbalance in conntrack kfuncs
  bpf, sockmap: Fix sk_redir use-after-free in send verdict
  selftests/bpf: Cover commuted pointer state propagation
  bpf: Propagate untrusted pointer state in commuted arithmetic
  bpf: Preserve pointer state for commuted arithmetic
  bpf: Simplify sanitize_err() signature
2026-08-07 08:08:57 -07:00
Eric Dumazet
8aecf0bbcc netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()
Incoming skbs passing through netfilter flowtable offload hooks (or XFRM
offload path) might already carry a ref-counted dst_entry assigned during
earlier RX or routing steps.

Calling skb_dst_set_noref() when skb already holds a ref-counted dst
overwrites skb->_skb_refdst, leaking the previous dst_entry reference
count and triggering a DEBUG_NET_WARN_ON_ONCE assertion in
skb_dst_check_unset():

  WARNING: at skb_dst_check_unset include/linux/skbuff.h:1170
  WARNING: at skb_dst_set_noref include/linux/skbuff.h:1234
  WARNING: at nf_flow_offload_ip_hook+0xf6c/0x2b60 net/netfilter/nf_flow_table_ip.c:864

Drop any existing dst_entry reference with skb_dst_drop(skb) before
setting the non-referenced flowtable destination.

Fixes: 2a79fd3908 ("netfilter: nf_flow_table: attach dst to skbs")
Reported-by: syzbot+76d4e3a055aec3b007ec@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a71b141.9511d2ce.1fc5b9.033b.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>
Link: https://patch.msgid.link/20260804093328.1831847-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-08-05 17:11:18 -07:00
Chengfeng Ye
fdeba03fea bpf: Fix netns reference imbalance in conntrack kfuncs
The opts argument of the BPF conntrack kfuncs can point to a shared
map value.  __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read
opts->netns_id separately when acquiring and releasing the network
namespace reference.

The reference imbalance can occur as follows:

  CPU 0                                  CPU 1
  read opts->netns_id (-1)
  skip get_net_ns_by_id()
                                         write opts->netns_id (id)
  read opts->netns_id (id)
  put_net(net) /* no matching get */

The reverse transition leaks the reference.  Repeating the unmatched put
can destroy a live namespace and crash later users.

The kernel reported:

  Oops: general protection fault, probably for non-canonical address
  KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
  RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700
  Call Trace:
   __sys_bpf+0x1662/0x50c0
   __x64_sys_bpf+0x73/0xb0
   do_syscall_64+0xf9/0x540
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
  Kernel panic - not syncing: Fatal exception

Snapshot every input field of opts with READ_ONCE() before validating or
using it.  The netns_id snapshot keeps the namespace get/put pair
balanced, while the other snapshots keep the remaining options from
changing partway through an invocation.  The individual reads can still
observe an inconsistent combination during a concurrent update, but each
selected field value remains stable for that invocation.

Fixes: aed8ee7feb ("net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup")
Fixes: d7e79c97c0 ("net: netfilter: Add kfuncs to allocate and insert CT")
Signed-off-by: Chengfeng Ye <nicoyip.dev@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/bpf/20260731160921.3245840-1-nicoyip.dev@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-08-01 20:45:24 +02:00
Julian Anastasov
99609cb0aa ipvs: return the csum validation for forward hook
Sashiko notes that playing games with the skb dst and rt
flags instead of providing hooknum is not a good idea
when validating the checksums.

Also, skipping checksum validation for FORWARD packets
risk silent data corruption, even if the only user is
the FTP-CMD packets coming from the real server.

Sashiko also noticed that by using common checksum
helper in the previous commit we actually fixed old bug
where the TCP/UDP checksum for IPv6 on CHECKSUM_COMPLETE
was not validated correctly.

Fixes: e876b75b90 ("ipvs: fix the checksum validations")
Link: https://sashiko.dev/#/patchset/20260722211420.153933-1-pablo%40netfilter.org
Link: https://sashiko.dev/#/patchset/20260727185024.67534-1-ja%40ssi.bg
Link: https://sashiko.dev/#/patchset/20260728202520.59179-1-ja%40ssi.bg
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:58:30 +02:00
Julian Anastasov
646922a037 ipvs: avoid out-of-bounds write in ip_vs_nat_icmp
Sashiko warns that local attacker can modify the packet
while it is processed by IPVS. Some places read the
IP ihl field multiple times which can cause out-of-bounds
access. One such place is ip_vs_nat_icmp where we
can write after the validated area.

Fix it by providing ciph argument just like it is done for
IPv6 and use ciph->len as offset to the embedded transport
header.

Modify some IPv4 header checks by reading the ihl field
only once.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Link: https://sashiko.dev/#/patchset/20260722101517.36313-1-ja%40ssi.bg
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:58:16 +02:00
Florian Westphal
7defddefa9 netfilter: ipset: switch to rcu work
In the initial ipset rhashtable conversion RFC series syzbot reported
following splat:

BUG: sleeping function [..] at kernel/irq_work.c:289
in_atomic(): 1, [..]
 irq_work_sync.. kernel/irq_work.c:289
 rhashtable_free_and_destroy.. lib/rhashtable.c:1295
 hash_netport4_destroy.. net/netfilter/ipset/ip_set_hash_gen.h:420
 ip_set_destroy_set_rcu.. net/netfilter/ipset/ip_set_core.c:1169
 rcu_core.. kernel/rcu/tree.c:2897

This is because post-rhashtable-conversion hash implementation needs
to schedule in the destroy callback.  At this time this isn't allowed.

Replace existing call_rcu() based destruction with rcu_work api.

Also allows to undo split of set destruction and gc work cancelling in
a future patch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:58:08 +02:00
Florian Westphal
cdd97fae0e netfilter: ipset: add and use mtype_del_cidr_all helper
Reduces size of upcoming rhashtable conversion.

Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:58:03 +02:00
Florian Westphal
c266769e9e netfilter: ipset: add small wrappers for hash and bucket sizes
Preparation patch.  Once the ipset hash table is replaced with rhashtable
these functions are needed. Add them in extra commit to have reviewable
chunks.

Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:57:53 +02:00
Jozsef Kadlecsik
712a6f545c netfilter: ipset: switch ext_size to atomic64_t
The hash types do not acquire set->lock, they use 'region locking' where
only part of the hash table is locked. Parallel inserts and deletes are
possible and CPUs can race on ->ext_size update.  Switch to atomic64_t.

This leaves another bug unresolved: there still can be a race on
comment extension re-init.  This will be handled in a later commit
when converting to rhashtable backend.

Fixes: f66ee0410b ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports")
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:57:38 +02:00
Jozsef Kadlecsik
8e5fd2a55e netfilter: ipset: rework cidr bookkeeping
According to sashiko, the current bookkeeping of cidr values are unsafe
on weakly-ordered architectures. Replace the in-place updating with an
RCU based method: create the new bookeeping structure, update and replace
the old one with the new. Downside that we need to allocate memory when
deleting a cidr entry - in case of memory pressure fall back to leave holes
which possibility is taken into account at evaluation time.

Thanks to Pablo (Pablo Neira Ayuso <pablo@netfilter.org>) and Cyntia
(Cynthia <cynthia@kosmx.dev>) for helping me in debugging which resulted
the patch "netfilter: ipset: allocate the proper memory for the generic
hash structure" on which this very patch depends.

Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:56:50 +02:00
Zhiling Zou
558f67f134 ipvs: stop estimator after disabled calc phase
IPVS estimator kthread 0 starts with zeroed chain and tick limits until
its initial calculation phase completes. If network namespace teardown
clears ipvs->enable during that phase, ip_vs_est_calc_phase() can return
without installing positive limits.

The kthread can then continue into its main loop and drain
est_temp_list with zero chain_max, tick_max and est_max_count values.
Each enqueue consumes one available tick row, but est_count never
reaches the zero est_max_count value. After all rows are consumed, the
row lookup returns IPVS_EST_NTICKS and ip_vs_enqueue_estimator() writes
past the ticks and tick_len arrays.

Exit kthread 0 after the calculation phase if the kthread is stopping or
IPVS has been disabled. That keeps temporary estimators from being
drained after the limits failed to initialize.

Estimator kthreads can now self-exit before teardown or reload stops
kd->task. Keep an extra task reference after creation and release it
with kthread_stop_put(), so kd->task remains valid until the stop paths
consume that reference.

Fixes: 705dd34440 ("ipvs: use kthreads for stats estimation")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-31 15:56:23 +02:00
Xiang Mei (Microsoft)
39e88f28fb netfilter: nft_payload: fix mask build for partial field offload
nft_payload_offload_mask() builds the offload match mask for a payload
expression that covers only part of a header field.  For a partial IPv6
address match (field_len = 16, priv_len = 1) that shift is 1 << 120, which
is undefined on the 32-bit int operand.  It also trims only one word, so
the remaining words stay 0xffffffff (and when priv_len is a multiple of 4
the trim is skipped entirely), leaving the mask covering more bytes than
the rule matches.

  UBSAN: shift-out-of-bounds in net/netfilter/nft_payload.c:278:20
  shift exponent 120 is too large for 32-bit type 'int'
  ...

The match is byte-granular and struct nft_data is zero-initialised, so the
correct mask is simply the first priv_len bytes set to 0xff. Set those
bytes directly and drop the word/shift trimming; this removes the undefined
shift and no longer over-masks the trailing bytes.

Fixes: a5d45bc0dc ("netfilter: nftables_offload: build mask based from the matching bytes")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 18:17:55 +02:00
Julian Anastasov
da7d894c41 ipvs: clear the nfct flag under lock
Sashiko warns that cp->flags should be changed under cp->lock

Fixes: 35dfb01314 ("ipvs: queue delayed work to expire no destination connections if expire_nodest_conn=1")
Fixes: f0a5e4d7a5 ("ipvs: allow connection reuse for unconfirmed conntrack")
Link: https://sashiko.dev/#/patchset/CALMqdkR704S2BG_QD_bgHTFp2%2B1QCi7n0T4zoZyTo8mDZevYSA%40mail.gmail.com
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 18:17:19 +02:00
Julian Anastasov
342e24a339 ipvs: do not mangle ICMP replies for non-first fragments
Sashiko warns that ip_vs_nat_icmp() unconditionally mangles the
payload for embedded non-first IPv4 fragments. The problem is
in the very old inverted pp->dont_defrag check which should not
continue when embedded is a non-first TCP/UDP/SCTP fragment.

Check for embedded non-first fragment is also missing from
ip_vs_out_icmp_v6(), it is needed before any connection
lookups that expect ports after the network headers.

Drop the blocking code from ip_vs_in_icmp_v6() which prevents
ICMPv6 from local clients to use non-MASQ forwarding.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Link: https://sashiko.dev/#/patchset/20260720201122.79882-1-ja%40ssi.bg
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 18:08:22 +02:00
Julian Anastasov
15cab31a37 ipvs: fix places with wrong packet offsets
The offsets we use to packet headers and payloads should be
based on skb->data. We even already respect non-zero
network offset in ip_vs_fill_iph_skb() but some places
do it wrongly and support only zero offset which is expected
for the IP layer where IPVS has hooks.

Change all places that instead of skb->data use offsets based
on the network header (skb_network_header, ip_hdr, etc) because
this doubles the network offset as noted by Sashiko.

For ip_vs_nat_icmp_v6() we can even rely on the IPv6 header
parsing done by the caller.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Link: https://sashiko.dev/#/patchset/20260710143733.29741-2-fw%40strlen.de
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 18:05:08 +02:00
Julian Anastasov
e876b75b90 ipvs: fix the checksum validations
ip_vs_in_icmp_v6() is missing checksum validation for ICMPv6
packets from clients. In fact, as for TCP/UDP we should
validate the checksum for ICMP packets only when we
mangle the packets on MASQ or on reply for tunnel.

Also, Sashiko points out that handle_response_icmp() being
common for IPv4 and IPv6 is missing the pseudo-header
calculation while validating ICMPv6 messages from real
servers which is a problem if checksum is not validated
by the hardware.

Fix the problems by creating ip_vs_checksum_common_check()
helper and use it for TCP/UDP/ICMP both for IPv4 and IPv6.
Rely on the nf_checksum() for validating the ICMP messages
but use it also for TCP and UDP.

Use correct IP offset for IP_VS_DBG_RL_PKT for TCP/UDP/SCTP.

IPVS packets (TCP/UDP/SCTP/ICMP) do not need checksum
validation on LOCAL_OUT (local clients or local real
servers) and on FORWARD (traffic from servers on LAN).
Do it only on LOCAL_IN, in case nf_checksum() is not
called on PRE_ROUTING.

Also, ip_vs_checksum_complete() can be marked static.

Fixes: 2a3b791e6e ("IPVS: Add/adjust Netfilter hook functions and helpers for v6")
Link: https://sashiko.dev/#/patchset/20260708180315.77413-1-ja%40ssi.bg
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 18:04:40 +02:00
Pablo Neira Ayuso
305b63e140 netfilter: xt_hashlimit: validate hashtable supports XT_HASHLIMIT_RATE_MATCH
The XT_HASHLIMIT_RATE_MATCH flag mode changes the semantics of the
dsthash_ent structure which represents an entry in the hashtable.  There
is a union area which uses a different layout to express the rate match
mode.

Update .checkentry path to validate the XT_HASHLIMIT_RATE_MATCH mode
flag is requested by two or more different rules that refer to the same
hashtable. Otherwise, uninitialized access to the burst field in the
union is possible.

Reject the use of the XT_HASHLIMIT_RATE_MATCH mode flag if set on by
revision less than 3 too.

Fixes: bea74641e3 ("netfilter: xt_hashlimit: add rate match mode")
Reported-and-tested-by: Talha Berk Arslan <talha.anything.info@gmail.com>
Link: https://patch.msgid.link/20260721074629.668-1-talha.anything.info@gmail.com/
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 18:01:25 +02:00
Pablo Neira Ayuso
f4f6997905 netfilter: nf_tables: make nft_object rhltable per table
The nft_object rhltable is global, this allows for accessing objects
that are being dismangled from lookup path by other existing netns.
Given the nft_obj_destroy() releases the object inmediately, this might
lead to use-after-free of these objects that are being released.
Make the existing rhltable per table to address this issue to deal with
with the nft_rcv_nl_event() path too.

Update nft_obj_lookup() to take the table as non-const, otherwise,
compiler complains when passing the objname_ht to rhltable_lookup().

Fixes: 4d44175aa5 ("netfilter: nf_tables: handle nft_object lookups via rhltable")
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 17:59:30 +02:00
Julian Anastasov
712d2993be ipvs: adjust double hashing when fwd method changes
Synced conns can be created with one forwarding method
and later updated with different one after the dest
server is configured. This needs adjusting the hashing
for node hn1 because only MASQ supports double hashing.

Modify conn_tab_lock() to support seeking for hash node
hn0 together with adding for hn1. By this way we can
safely modify the forwarding method and hn1.hash_key
under bucket lock for the first node hn0. The forwarding
method is also protected by cp->lock as it is part of
cp->flags.

Fix the usage of stale idx/idx2 values in conn_tab_lock
after jumping to the retry label. Instead, use idx/idx2
values just to order the locking for the old/new tables.

Reported-by: Zhiling Zou <roxy520tt@gmail.com>
Link: https://patch.msgid.link/1b914f41d725bc064c9ba9830dc8169329737270.1782540466.git.roxy520tt@gmail.com/
Link: https://sashiko.dev/#/patchset/CALMqdkR704S2BG_QD_bgHTFp2%2B1QCi7n0T4zoZyTo8mDZevYSA%40mail.gmail.com
Fixes: f20c73b046 ("ipvs: use more keys for connection hashing")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 17:59:20 +02:00
Zhiling Zou
a63d2dbaeb ipvs: do not propagate one-packet flag to synced conns
Synced connections can be created before their destination exists. When
the destination is later added, ip_vs_bind_dest() copies connection flags
from the destination into cp->flags.

IP_VS_CONN_F_ONE_PACKET connections are not synced. If a synced
connection inherits IP_VS_CONN_F_ONE_PACKET while it is already hashed,
expiry can treat it as a one-packet connection and skip unlinking the
existing conn_tab node, leaving stale hash nodes pointing at a freed
struct ip_vs_conn.

Drop IP_VS_CONN_F_ONE_PACKET from destination flags when binding synced
connections.

Fixes: 26ec037f98 ("IPVS: one-packet scheduling")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Zhiling Zou <roxy520tt@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 17:59:02 +02:00
David Lee
f30415929b netfilter: ipset: do not update comments from kernel-side hash adds
mtype_resize() copies comment pointers with memcpy(), not the comment
objects themselves. During the window after an entry has been copied but
before the table swap and backlog replay, the old table is still
published for packet-side updates while the replacement-table entry
already holds the same ip_set_comment_rcu pointer.

If xt_SET --add-set ... --exist hits that old entry in this window,
mtype_add() calls ip_set_init_comment() even though packet-side adds
carry no comment payload. That call frees the shared comment through the
old entry, so the replacement-table entry now holds a stale pointer.
When the queued add is replayed on the new table, mtype_add() calls
ip_set_init_comment() again and strlen() dereferences the stale pointer.

Fix this in mtype_add() by skipping ip_set_init_comment() when
ext->target marks a packet-side add. Userspace adds still update
comments, while packet-side adds can no longer free comment storage
shared with a resize copy.

Fixes: f66ee0410b ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports")
Cc: stable@vger.kernel.org
Signed-off-by: David Lee <david.lee@trailofbits.com>
Assisted-by: Codex:gpt-5.5
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-23 17:58:46 +02:00
Pablo Neira Ayuso
4aa63842fc netfilter: nf_conntrack_expect: add and use nf_ct_expect_related_pair()
Add a new function to insert a pair of expectations, this is required by
the SIP and H323 NAT helpers. The spinlock is held to check if there is
a slot for both expectations, in such case, insert them.

This removes the need for nf_ct_unexpect_related() inside the loop to
find a pair of consecutive ports, otherwise inserting expectations whose
dead flag is already set on can happen.

Bump master_help->expecting for the expectation class after checking if
the expectation fits in the master expectation list, which is needed for
this new _pair() function variant to run the eviction routine including
the preallocated slot for the first expectation in the pair.

Fixes: b8b09dc2bf ("netfilter: nf_conntrack_expect: use conntrack GC to reap expectations")
Reported-by: Jaeyeong Lee <iostreampy@proton.me>
Link: https://patch.msgid.link/178377968720.33756.12204817361601593230@proton.me/
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-22 20:34:28 +02:00
Xiang Mei
db3d0e0e5d netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()
sip_help_tcp() stores the size change of each NAT-rewritten SIP message
in s16 diff and accumulates it in s16 tdiff, but a single message can
grow by more than S16_MAX while the packet stays under the 65535
enlarge_skb() limit: nf_nat_sip() rewrites every matching URI, and a long
Contact list expands the message by tens of kilobytes. diff then wraps,
and "datalen = datalen + diff - msglen" yields a huge unsigned datalen,
so the next iteration's ct_sip_get_header() reads past the linearized skb
tail.

Widen diff, tdiff and the seq_adjust hook to s32. Both are bounded by the
65535 byte packet limit, and the seqadj core is already s32
(nf_ct_seqadj_set() takes s32), so no previously accepted input is
rejected.

  BUG: KASAN: use-after-free in ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464)
  Read of size 1 at addr ffff888010800000 by task ksoftirqd/1/25
   ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464)
   sip_help_tcp (net/netfilter/nf_conntrack_sip.c:1694)
   nf_confirm (net/netfilter/nf_conntrack_proto.c:183)
   nf_hook_slow (net/netfilter/core.c:619)
   ip6_output (net/ipv6/ip6_output.c:246)
   ip6_forward (net/ipv6/ip6_output.c:690)
   ipv6_rcv (net/ipv6/ip6_input.c:351)
   __netif_receive_skb_one_core (net/core/dev.c:6212)
   process_backlog (net/core/dev.c:6676)
   __napi_poll (net/core/dev.c:7735)
   net_rx_action (net/core/dev.c:7955)
   handle_softirqs (kernel/softirq.c:622)
   run_ksoftirqd (kernel/softirq.c:1076)
   ...

Fixes: f5b321bd37 ("netfilter: nf_conntrack_sip: add TCP support")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Link: https://patch.msgid.link/netfilter-devel/20260712234201.3213635-1-xmei5@asu.edu
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2026-07-22 19:47:17 +02:00
Florian Westphal
f468c48d48 netfilter: xt_physdev: masks are not c-strings
... and must not be subjected to the 'nul terminated' constraint.
If the interface name is 15 characters long, the mask is 16-bytes
'0xff' (to cover for \0) and the valid device name is rejected.

Fixes: 8df772afc9 ("netfilter: x_physdev: reject empty or not-nul terminated device names")
Cc: stable@vger.kernel.org
Closes: https://bugs.launchpad.net/neutron/+bug/2159935
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Julian Anastasov
b3fe4cbd58 ipvs: fix more places with wrong ipv6 transport offsets
Sashiko reports for more incorrect IPv6 transport offsets.

The app code for TCP was assuming IPv4 network header
even after the ipvsh argument was provided. This can
cause problems with apps over IPv6. As for the only
official app in the kernel tree (FTP) this problem is
harmless because we use Netfilter to mangle the FTP
ports and we do not adjust the TCP seq numbers.

Also, provide correct offset of the ICMPV6 header in
ip_vs_out_icmp_v6() for correct checksum checks when
the IPv6 packet has extension headers.

Fixes: d12e12299a ("ipvs: add ipv6 support to ftp")
Fixes: 2a3b791e6e ("IPVS: Add/adjust Netfilter hook functions and helpers for v6")
Cc: stable@vger.kernel.org
Link: https://sashiko.dev/#/patchset/20260706101624.69471-1-zhaoyz24%40mails.tsinghua.edu.cn
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Florian Westphal
a2f57827bf ipvs: reload ip header after head reallocation
__ip_vs_get_out_rt() calls skb_ensure_writable() which may
reallocate skb->head.

Fixes: 8d8e20e2d7 ("ipvs: Decrement ttl")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-sonnet-4-6
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Pablo Neira Ayuso
90941d9c92 netfilter: flowtable: use correct direction to set up tunnel route
The layer 2 encapsulation and layer 3 tunnel information in the xmit
path is taken from the other tuple, because the tunnel information that
is included in the tuple for hashtable lookups is also used to perform
the egress encapsulation in the transmit path.

This patch uses the correct direction when setting up the tunnel, the
original proposed patch to address this fix uses the reversed direction.

While at it, remove the redundant check to call dst_release() to drop
the reference on the dst that was obtained from the forward path, which
is not useful in the direct xmit path unless tunneling is performed.

Fixes: fa7395c02d ("netfilter: flowtable: support IPIP tunnel with direct xmit")
Cc: stable@vger.kernel.org
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Yizhou Zhao
f62c41b491 netfilter: nf_conncount: fix zone comparison in tuple dedup
The "already exists" dedup logic in __nf_conncount_add() decides
whether a connection has already been counted and can be skipped instead
of incrementing the connlimit count.  It compares the conntrack zone of a
list entry with the zone of the connection being added using
nf_ct_zone_id() and nf_ct_zone_equal(), passing conn->zone.dir or
zone->dir as the direction argument.

Those helpers take enum ip_conntrack_dir values: IP_CT_DIR_ORIGINAL is 0
and IP_CT_DIR_REPLY is 1.  However, zone->dir is a u8 bitmask:
NF_CT_ZONE_DIR_ORIG is 1, NF_CT_ZONE_DIR_REPL is 2 and
NF_CT_DEFAULT_ZONE_DIR is 3.  Passing that bitmask as the enum direction
shifts the meaning of every non-zero value.  An ORIG-only zone passes 1
and is tested as REPLY, while REPL-only and default zones pass 2 or 3 and
test bits beyond the valid direction range.  In those cases
nf_ct_zone_id() can fall back to NF_CT_DEFAULT_ZONE_ID instead of using
the real zone id, so different zones can be treated as equal and dedup
collapses to tuple equality alone.

nf_conncount stores and compares the original-direction tuple for a
connection.  If an skb already has an attached conntrack entry,
get_ct_or_tuple_from_skb() explicitly copies
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, regardless of the packet's
ctinfo.  Therefore the zone comparison in the tuple dedup path must use
IP_CT_DIR_ORIGINAL as well; the zone direction bitmask describes where a
zone id applies, not which direction this conncount tuple represents.

Fix the two dedup comparisons by passing IP_CT_DIR_ORIGINAL directly.
Do not special-case NF_CT_DEFAULT_ZONE_DIR and do not compare raw zone
ids: using the existing helpers with IP_CT_DIR_ORIGINAL preserves the
direction-aware NF_CT_DEFAULT_ZONE_ID fallback.  A default bidirectional
zone contains the ORIG bit, so it naturally returns the real zone id;
reply-only zones continue to fall back for original-direction tuple
comparisons.

Fixes: 21ba8847f8 ("netfilter: nf_conncount: Fix garbage collection with zones")
Fixes: b36e4523d4 ("netfilter: nf_conncount: fix garbage collection confirm race")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Yizhou Zhao
b06163ce52 netfilter: ecache: fix inverted time_after() check
ecache_work_evict_list() redelivers DESTROY events for conntracks that
were moved to the per-netns dying_list after event delivery failed.  It
sets a 10ms deadline:

    stop = jiffies + ECACHE_MAX_JIFFIES

but then tests:

    time_after(stop, jiffies)

This condition is true while the deadline is still in the future, so the
worker returns STATE_RESTART after the first successful redelivery in the
usual case.  ecache_work() maps STATE_RESTART to delay 0, which turns the
redelivery path into one dying conntrack per workqueue dispatch and makes
the sent > 16 batching/cond_resched() path effectively unreachable.

A conntrack netlink listener whose receive queue is congested can make
DESTROY event delivery fail with -ENOBUFS.  With sustained conntrack
churn, entries then accumulate on the dying_list and are only drained at
the degraded one-entry-per-dispatch rate once delivery succeeds again,
wasting CPU on back-to-back workqueue reschedules and prolonging
conntrack memory/resource pressure.

In a KASAN QEMU test with CONFIG_NF_CONNTRACK_EVENTS=y and
nf_conntrack.enable_hooks=1, a congested DESTROY listener caused 8192
nf_ct_delete() calls to return false and move entries to the dying_list.
After closing the listener, the unfixed kernel needed 7670 ecache_work()
entries to destroy 7669 conntracks.  With this change, the same 8192
entries were destroyed by 2 ecache_work() entries.

Swap the comparison so the worker restarts only after the deadline has
expired.

Fixes: 2ed3bf188b ("netfilter: ecache: use dedicated list for event redelivery")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Wyatt Feng
5d1a224093 netfilter: xt_nat: reject unsupported target families
xt_nat SNAT and DNAT target handlers assume IP-family conntrack state
is present and can dereference a NULL pointer when instantiated from an
unsupported family through nft_compat. A bridge-family compat rule can
therefore trigger a NULL-dereference in nf_nat_setup_info().

Reject non-IP families in xt_nat_checkentry() so unsupported targets
cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT
compat users and leave the runtime fast path unchanged.

[ The crash was fixed via
  9dbba7e694 ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"),
  so this patch is no longer critical.
  Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra
  family check is a good idea in any case. ]

Fixes: c7232c9979 ("netfilter: add protocol independent NAT core")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-10 16:28:47 +02:00
Julian Anastasov
3f7a535ff0 ipvs: ensure inner headers in ICMP errors are in headroom
Sashiko points out that after stripping the outer headers
with pskb_pull() we should ensure the inner IP headers
in ICMP errors from tunnels are present in the skb headroom
for functions like ipv4_update_pmtu(), icmp_send() and
IP_VS_DBG().

Also, add more checks for the length of the inner headers.

Fixes: f2edb9f770 ("ipvs: implement passive PMTUD for IPIP packets")
Link: https://sashiko.dev/#/patchset/20260702073430.67680-1-zhaoyz24%40mails.tsinghua.edu.cn
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Yizhou Zhao
2f75c0faa3 ipvs: use parsed transport offset in SCTP state lookup
set_sctp_state() reads the SCTP chunk header again in order to drive the
IPVS SCTP state table. For IPv6 it computes the offset with
sizeof(struct ipv6hdr), while the surrounding IPVS code uses iph.len from
ip_vs_fill_iph_skb(), where ipv6_find_hdr() has already skipped
extension headers and found the real transport header.

This makes the state machine read from the wrong offset for IPv6 SCTP
packets that carry extension headers. For example, an INIT packet with an
8-byte destination options header can be scheduled correctly by
sctp_conn_schedule(), but set_sctp_state() reads the first byte of the
SCTP verification tag as a DATA chunk type. The connection then moves
from NONE to ESTABLISHED instead of INIT1, gets the longer established
timeout, and updates the active/inactive destination counters
incorrectly. This happens even though the SCTP handshake has not
completed.

Use the parsed transport offset passed down from ip_vs_set_state() for
the SCTP chunk-header lookup. For IPv4 and IPv6 packets without
extension headers this preserves the existing offset.

Fixes: 2906f66a56 ("ipvs: SCTP Trasport Loadbalancing Support")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/netdev/20260705123040.35755-1-zhaoyz24@mails.tsinghua.edu.cn/
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Yizhou Zhao
2500fa3958 ipvs: use parsed transport offset in TCP state lookup
TCP state handling reparses the skb to find the TCP header. For IPv6 it
uses sizeof(struct ipv6hdr), while the surrounding IPVS code already
parsed the packet with ip_vs_fill_iph_skb() and has the real
transport-header offset in iph.len.

This makes TCP state handling look at the wrong bytes when an IPv6
packet carries extension headers. Use the parsed transport offset passed
down from ip_vs_set_state() when reading the TCP header.

For IPv4 and for IPv6 packets without extension headers, the passed
offset matches the previous value.

Fixes: 0bbdd42b7e ("IPVS: Extend protocol DNAT/SNAT and state handlers")
Link: https://lore.kernel.org/netdev/20260705125659.37744-1-zhaoyz24@mails.tsinghua.edu.cn/
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Yizhou Zhao
bae7ce7baf ipvs: pass parsed transport offset to state handlers
IPVS callers already parse the packet into struct ip_vs_iphdr before
updating connection state. For IPv6 this records the real
transport-header offset after extension headers in iph.len.

Pass this parsed transport offset through ip_vs_set_state() and the
protocol state_transition() callback so protocol handlers can use the
same packet context as scheduling and NAT handling. This patch only
changes the common callback plumbing and adapts the protocol callback
signatures; TCP and SCTP start using the value in follow-up patches.

Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Florian Westphal
da5b58478a netfilter: handle unreadable frags
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: 65249feb6b ("net: add support for skbs with unreadable frags")
Cc: stable@vger.kernel.org
Acked-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Pablo Neira Ayuso
fa7395c02d netfilter: flowtable: support IPIP tunnel with direct xmit
The combination of IPIP tunnel with direct xmit, eg. bridge device,
breaks because no dst_entry is provided to check the skb headroom and to
set the iph->frag_off field. This leads to invalid dst usage and can
trigger a crash in the tunnel transmit path.

Fix this by moving dst_cache and dst_cookie out of the runtime union so
that they can be shared by neighbour, xfrm, and direct tunnel flows.
For FLOW_OFFLOAD_XMIT_DIRECT tuples carrying tunnel metadata, preserve
route state in these shared fields and release it through the common
dst release path.

Since dst_entry is now available to the three supported xmit modes and
dst_release() already deals with NULL dst, remove the xmit type check
in nft_flow_dst_release(). Moreover, skip the check if the dst entry
is NULL in nf_flow_dst_check() which is now the case for the direct
xmit case.

Based on patch from Rein Wei <n05ec@lzu.edu.cn>.

Fixes: d30301ba4b ("netfilter: flowtable: Add IPIP tx sw acceleration")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported-by: Zhengyang Chen <chzhengyang2023@lzu.edu.cn>
Reported-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Pablo Neira Ayuso
6c5dcab95f netfilter: flowtable: IPIP tunnel hardware offload is not yet support
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: d98103575d ("netfilter: flowtable: Add IP6IP6 rx sw acceleration")
Fixes: ab427db178 ("netfilter: flowtable: Add IPIP rx sw acceleration")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported-by: Zhengyang Chen <chzhengyang2023@lzu.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Pablo Neira Ayuso
c328b90c17 netfilter: flowtable: use dst in this direction when pushing IPIP header
When pushing the IPIP header, the route of the other direction is used
to calculate the headroom, use the route in this direction. Accessing
the other tuple to set the IP source and destination is fine because
this tuple does not provide such information to avoid storing redundant
information. However, this tuple already provides the dst for this
direction, this went unnoticed because this bug affects headroom and
iph->frag_off only at this stage.

Fixes: d30301ba4b ("netfilter: flowtable: Add IPIP tx sw acceleration")
Fixes: 93cf357fa7 ("netfilter: flowtable: Add IP6IP6 tx sw acceleration")
Cc: stable@vger.kernel.org
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Jozsef Kadlecsik
724f32699a netfilter: ipset: allocate the proper memory for the generic hash structure
Because a single create function is emitted for every hash type,
from the IPv4 and IPv6 generic hash structure definitions the last
one, i.e. the IPv6 was in effect for IPv4 too. Use the proper size
when allocating the structure. Comment properly that because create()
refers to elements of the generic hash structure, all referred ones
must come before the IPv4/IPv6 dependent 'next' member.

Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:44 +02:00
Jozsef Kadlecsik
672321302e netfilter: ipset: cleanup the add/del backlog when resize failed
Sashiko pointed out that the add/del backlog was not cleaned up
when resize failed. Fix it in the corresponding error path. Also,
make sure that the add/del backlog is htable-specific so when
resize creates a new htable, old/new backlog can't be mixed up.

Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:43 +02:00
Jozsef Kadlecsik
cffcf57bf0 netfilter: ipset: exclude gc when resize is in progress
Zhengchuan Liang and Eulgyu Kim reported that because resize
does not copy the comment extension into the resized set but
uses it's pointer, ongoing gc can free the extension in the
original set which then results stale pointer in the resized
one. The proposed patch was to recreate the extensions for
every element in the resized set. It is both expensive and
wastes memory, so better exclude gc when resizing in progress
detected: resizing will destroy the original set anyway,
so doing gc on it is unnecessary.

Introduce a new spinlock to exclude parallel gc and resize.
Because we just set and check a bool value, there's no need
for the parameter to be atomic_t and rename it for better
readability.

Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported by: Eulgyu Kim <eulgyukim@snu.ac.kr>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:43 +02:00
Jozsef Kadlecsik
5d0c22e736 netfilter: ipset: mark the rcu locked areas properly
When we bump the uref counter, there's no need to keep
the rcu lock because the referred hash table can't
disappear. Also, from the same reason in mtype_gc we
need the rcu lock and not a spinlock.

Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:43 +02:00
Tamaki Yanagawa
e6107a4c74 netfilter: nft_lookup: fix catchall element handling with inverted lookups
nft_lookup_eval() decides whether a lookup matched (`found`) from the
direct set lookup and priv->invert before falling back to the
catchall element used by interval sets (e.g. nft_set_rbtree) for the
open-ended default range. Since `found` is never recomputed after
`ext` is replaced by the catchall lookup, inverted lookups
(NFT_LOOKUP_F_INV, "!= @set") can wrongly match or wrongly skip the
catchall element, producing the wrong verdict. Fold the catchall
lookup into `ext` before computing `found`, matching the order
already used by nft_objref_map_eval().

Fixes: aaa31047a6 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Tamaki Yanagawa <ty@000ty.net>
Assisted-by: Claude:claude-sonnet-5
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-08 15:33:37 +02:00
Wyatt Feng
1b47026fb4 netfilter: xt_connmark: reject invalid shift parameters
Revision 2 of the CONNMARK target accepts user-controlled shift
parameters and applies them to 32-bit mark values in
connmark_tg_shift().

A shift_bits value of 32 or more triggers an undefined-shift bug when
the rule is evaluated. Invalid shift_dir values are also accepted and
silently fall back to the left-shift path.

Reject invalid revision-2 shift parameters in connmark_tg_check() so
malformed rules fail at installation time, before they can reach the
packet path.

Fixes: 472a73e007 ("netfilter: xt_conntrack: Support bit-shifting for CONNMARK & MARK targets.")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <dstsmallbird@foxmail.com>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Reviewed-by: Ren Wei <enjou1224z@gmail.com>
Reviewed-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00
Yizhou Zhao
2975324d16 ipvs: reset full ip_vs_seq structs in ip_vs_conn_new
Commit 9a05475ceb ("ipvs: avoid kmem_cache_zalloc in
ip_vs_conn_new") changed ip_vs_conn_new() to allocate an ip_vs_conn
object with kmem_cache_alloc().  The function then initializes many
fields explicitly, but only resets in_seq.delta and out_seq.delta in the
two struct ip_vs_seq members.

That leaves init_seq and previous_delta uninitialized.  This is normally
harmless while the corresponding IP_VS_CONN_F_IN_SEQ or
IP_VS_CONN_F_OUT_SEQ flag is clear.  For connections learned from a sync
message, however, ip_vs_proc_conn() preserves those flags from
IP_VS_CONN_F_BACKUP_MASK and passes opt=NULL when the message omits
IPVS_OPT_SEQ_DATA.  In that case the new connection can be hashed with
SEQ flags set but with the rest of in_seq/out_seq still containing stale
slab data.

When a packet for such a connection is later handled by an IPVS
application helper, vs_fix_seq() and vs_fix_ack_seq() use
previous_delta and init_seq to rewrite TCP sequence numbers.  A malformed
sync message can therefore make forwarded packets carry stale slab bytes
in their TCP seq/ack numbers, and can also corrupt the forwarded TCP
flow.

Reset both struct ip_vs_seq members completely before publishing the
connection.  This matches the existing "reset struct ip_vs_seq" comment
and keeps the sequence-adjustment gates inactive unless valid sequence
data is installed later.

Fixes: 9a05475ceb ("ipvs: avoid kmem_cache_zalloc in ip_vs_conn_new")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00
Yizhou Zhao
6b335af0d0 ipvs: fix PMTU for GUE/GRE tunnel ICMP errors
When an ICMP Fragmentation Needed error is received for a tunneled IPVS
connection, ip_vs_in_icmp() recomputes the MTU that the original packet
can use by subtracting the tunnel overhead from the reported next-hop
MTU.

The current code always subtracts sizeof(struct iphdr), which is only
the IPIP overhead. For GUE and GRE tunnels, ipvs_udp_decap() and
ipvs_gre_decap() already compute the additional tunnel header length,
but that value is scoped to the decapsulation block and is lost before
the ICMP_FRAG_NEEDED handling. As a result, the ICMP error sent back to
the client advertises an MTU that is too large, so PMTUD can fail to
converge for GUE/GRE-tunneled real servers.

With a reported next-hop MTU of 1400, a GUE tunnel currently returns
1380 to the client. The correct value is 1368:

  1400 - sizeof(struct iphdr) - sizeof(struct udphdr) -
  sizeof(struct guehdr)

Hoist the tunnel header length into the main ip_vs_in_icmp() scope and
subtract sizeof(struct iphdr) + ulen in the Fragmentation Needed path.
The IPIP path keeps ulen as 0, so its existing 1400 - 20 = 1380 result
is unchanged.

Fixes: 508f744c0d ("ipvs: strip udp tunnel headers from icmp errors")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00
Pablo Neira Ayuso
d63611cbe8 netfilter: nft_set_rbtree: get command skips end element with open interval
The get command on intervals provide partial matches such as subranges
for usability reasons. However, an open interval has no closing end
element. If the closing element matches within the range of the open
internal, ie. its closest match is the start element of the open range,
then, return 0 but offer no matching element to userspace through
netlink as a special case. Userspace provides at least a matching start
element in this case and the closing end element matching the open
interal is ignored.

Another possibility is to report the matching start element of the open
interval for this end interval. However, this results in duplicated
matching being listed in userspace because userspace does not expect a
start element as response to a end element.

Fixes: 2aa34191f0 ("netfilter: nft_set_rbtree: use binary search array in get command")
Reported-by: Melbin K Mathew <mlbnkm1@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00
Pablo Neira Ayuso
278296b69f netfilter: nfnetlink_cthelper: cap to maximum number of expectation per master on updates
Really cap it to NF_CT_EXPECT_MAX_CNT (255) on updates.

The commit ("netfilter: nfnetlink_cthelper: cap to maximum number of
expectation per master") only covers creation of helpers, not updates.

Fixes: 397c830097 ("netfilter: nf_conntrack_helper: cap maximum number of expectation at helper registration")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00
Feng Wu
444853cd43 netfilter: xt_rateest: fix u64 truncation in xt_rateest_mt()
On links faster than ~34 Gbps, where byte rate may exceed 2^32-1
(~ 4.3 GBps), the comparison result becomes incorrect because the
truncated value no longer reflects the actual estimator rate.

Fix by changing the local variables to u64.

Fixes: 1c0d32fde5 ("net_sched: gen_estimator: complete rewrite of rate estimators")
Signed-off-by: Feng Wu <wufengwufengwufeng@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00
Wyatt Feng
64cdf7d30a netfilter: xt_u32: reject invalid shift counts
u32_match_it() executes rule-supplied shift operands on a 32-bit
value. A malformed u32 rule can provide a shift count of 32 or more,
triggering an undefined shift out-of-bounds during packet evaluation.

Validate XT_U32_LEFTSH and XT_U32_RIGHTSH operands in
u32_mt_checkentry() and reject malformed rules before they reach the
packet path.

Fixes: 1b50b8a371 ("[NETFILTER]: Add u32 match")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
2026-07-03 14:45:21 +02:00