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https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
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https://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec.git
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syzbot reported a null-ptr-deref in __ip6_del_rt_siblings() [0].
The stack trace hinted towards a null dereference of rt->fib6_node when
fn->leaf is accessed in __ip6_del_rt_siblings(). With
RTNL_FLAG_DOIT_UNLOCKED set, inet6_rtm_delroute() operations run
concurrently without acquiring the RTNL lock. In ip6_route_del(), the
route lookup happens under rcu_read_lock() without acquiring
table->tb6_lock.
Between ip6_route_del() looking up the route and __ip6_del_rt_siblings()
acquiring table->tb6_lock, another thread can modify the routing table.
For example, when an ECMP route is replaced via RTM_NEWROUTE with
NLM_F_REPLACE, fib6_add_rt2node() unlinks all old siblings and sets
iter->fib6_node = NULL. A reproducer was found that triggers this [1].
Add a check to ensure rt->fib6_node is non-null before accessing it.
[0]
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
RIP: 0010:__ip6_del_rt_siblings+0x31e/0x7c0 net/ipv6/route.c:4056
Call Trace:
<TASK>
ip6_route_del+0x1054/0x1110 net/ipv6/route.c:4232
inet6_rtm_delroute+0x5d7/0x6d0 net/ipv6/route.c:5669
rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0x565/0x870 net/socket.c:2713
___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
__sys_sendmsg net/socket.c:2799 [inline]
__do_sys_sendmsg net/socket.c:2804 [inline]
__se_sys_sendmsg net/socket.c:2802 [inline]
__x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2802
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
[1] https://gist.github.com/NamanGulati/0766a1159b6ca61928faaf87425ff899
Fixes: bd11ff421d36 ("ipv6: Get rid of RTNL for SIOCDELRT and RTM_DELROUTE.")
Reported-by: syzbot+a73e5ee0fd534fed75bd@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a9b03f9.04649fcc.10325f.0003.GAE@google.com
Signed-off-by: Naman Gulati <namangulati@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260904180645.706425-1-namangulati@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf
Pablo Neira Ayuso says:
====================
Netfilter/IPVS fixes for net
The following patchset contains Netfilter/IPVS fixes for net:
1) Reject malformed messages in IPVS sync, from Kyle Zeng.
2) Fix possible stale infoleak in IPVS sync, also from Kyle Zeng.
3) Out-of-bound read in the SIP conntrack helper, from
Joas Antonio dos Santos.
4) UaF on cttimeout module removal, from Chengfeng Ye.
5) Unregister nf_loggers before netns teardown to fix UaF,
also from Chengfeng Ye.
6) Fix race in nfnetlink_log due to concurrent instance destruction,
from Florian Westphal.
7) Remove arp_table 32bit compat interface, this is already off in
many distributions, from Florian Westphal.
8) Set IP6T_F_PROTO flag is e->ipv6.proto is set on to deal with
insufficient validation of xtables extensions when used from
legacy ip6tables, from Florian.
9) Set on the NLM_F_DUMP_FILTERED flag when all is filtering out
in ctnetlink, from Ilya Maximets.
* tag 'nf-26-09-07' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: report NLM_F_DUMP_FILTERED when all is filtered out
netfilter: ip6_tables: set F_PROTO when proto value is nonzero
netfilter: arp_tables: remove the 32bit compat interface
netfilter: nfnetlink_log: cope with concurrent instance destruction
netfilter: nf_log: unregister loggers before per-net teardown
netfilter: cttimeout: prevent UAF during module unload
netfilter: nf_conntrack_sip: fix OOB read in sip_skip_whitespace()
ipvs: fix reversed sequence option serialization
ipvs: reject invalid states in connection template sync records
====================
Link: https://patch.msgid.link/20260907171732.1407739-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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After commit cd51b74bdd0b ("ipv6: Fix redirect exception creation for
UDP/RAW sockets") the two redirect calls are now equivalent and there is
no need to specifically call ip6_redirect() for tunnel sockets. Simplify
and call ip6_sk_redirect() for both tunnel sockets and regular sockets.
Note that for ICMPv6 Redirect Message packets the VRF driver does not
reset skb->dev to the VRF device, so skb->dev->ifindex is equivalent to
inet6_iif(skb), even when the packet was received from a VRF port.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260907101358.596953-1-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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ipv6_flowlabel_get() allocates an ipv6_fl_socklist entry for every
successful GET. The recheck path for a compatible existing flowlabel
links another lease without applying any lease admission check. Repeated
GET requests for one shareable label can therefore grow a socket's lease
list without bound.
Reject a new unprivileged lease once the socket already holds
FL_MAX_PER_SOCK leases. Check this on the shared recheck path so reuse
of a globally interned label, including the fl_intern() collision path,
is covered as well. New-label admission remains under the existing
mem_check() policy.
Use capable(CAP_NET_ADMIN) rather than ns_capable(), matching
mem_check(). An unprivileged user must not bypass the cap by creating a
user namespace and a netns where they have CAP_NET_ADMIN, which would
still consume host memory.
Check the capability only when the socket reaches the limit, so
successful unprivileged GET requests below the cap do not generate a
capability audit. Do the admission check before updating linger and
expires so a rejected GET does not refresh the shared label, matching
the existing socket-list allocation failure path.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/83f8535972ff6e3741548476a1d50dec24c758be.1788415194.git.zhilinz@nebusec.ai
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Fix typos in comments, reported by scripts/checkpatch.pl using the
misspelling list in scripts/spelling.txt. Only touches comments, no code
changes.
Signed-off-by: Hemanth Selam <hemanth.selam@gmail.com>
Link: https://patch.msgid.link/20260904122157.29281-1-hemanth.selam@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Recently, IPV6_ADDRFORM has received many AI-driven bug reports.
Fixing them properly would needlessly churn the fast paths in TCP
and UDP.
IPV6_ADDRFORM was initially introduced in RFC 2133 in 1997,
but only two years later, it was removed from RFC 2553 in 1999.
In 2026, modern applications natively support dual-stack sockets;
notably, systemd's socket activation does not use IPV6_ADDRFORM.
Also, getsockopt(IPV6_ADDRFORM) can be replaced with SO_DOMAIN.
Let's remove IPV6_ADDRFORM.
Later, we can remove sk->sk_prot_creator and revert commit
c26c192c3d48 ("udp: properly deal with xfrm encap and ADDRFORM").
Reported-by: Daehyeon Ko <4ncienth@gmail.com>
Closes: https://lore.kernel.org/netdev/20260902010408.1057857-1-4ncienth@gmail.com/
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Closes: https://lore.kernel.org/netdev/20260824033331.1084971-1-imv4bel@gmail.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260904033543.2635540-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This commit bounds cork->base.fragsize to IP6_MAX_MTU for UDP sockets to
avoid a possible overflow of UDP length that triggers a WARN in
udp_set_len_short when setsockopt IPV6_MTU_DISCOVER is set to
IPV6_PMTUDISC_DO or IPV6_PMTUDISC_PROBE, and a large packet is sent over
a netdev with an unusually large MTU.
Steps to reproduce (included in the new selftest):
1. Set device MTU bigger than IP6_MAX_MTU. cork->base.fragsize will be
set to that MTU in ip6_setup_cork.
2. Set IPV6_MTU_DISCOVER to IPV6_PMTUDISC_PROBE or IPV6_PMTUDISC_DO. It
lets maxnonfragsize be set to device MTU (cork->fragsize) in
__ip6_append_data, rather than to IP6_MAX_MTU.
3. Send 65528 bytes of payload (+8 bytes of UDP header, +40 bytes of
IPv6 header). Device MTU allows it (it's only one byte bigger than
IP6_MAX_MTU, and the device MTU is bigger than that).
4. The UDP length in the built packet is 65536, which overflows the
16-bit length field and triggers the WARN in udp_set_len_short.
To avoid breaking sending UDP jumbograms over raw IPv6 sockets, limit
the change to UDP sockets only.
The original overflow bug with IPv6 and IPV6_PMTUDISC_DO seems to
predate git history (verified reproduction on 2.6.21), was fixed later,
and then reappeared in commit 427faee167bc ("net: ipv6: introduce
ip6_dst_mtu_maybe_forward"), which is chosen as the Fixes tag here. The
overflow with IPV6_PMTUDISC_PROBE reproduces since its introduction in
commit 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE").
Fixes: 427faee167bc ("net: ipv6: introduce ip6_dst_mtu_maybe_forward")
Reported-by: syzbot+ce13c07d96d04716eaa2@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a6a966c.86abc875.e5c3d.0054.GAE@google.com/
Signed-off-by: Alice Mikityanska <alice@isovalent.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260901195714.673548-3-alice.kernel@fastmail.im
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The ip6tables traverser doesn't search the extension header chain unless
userspace did set the IP6T_F_PROTO flag.
This also means that userspace that sets the e->ipv6.proto flag can bypass
the protocol check for the rule by not setting this flag.
That in turn means that all ip6_tables modules and targets that want to
reject rules without '-p' flag MUST also check for that flag.
Not all do, likely because they got copied from iptables which lacks
this flag (no extension headers).
Instead of fixing up all the relevant targets, emulate ip6tables behaviour
in the kernel (like nft_compat.c) and set the flag if the protocol is set.
Reported-by: Zhiling Zou <zhilinz@nebusec.ai>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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neigh_table is now per-netns, so struct pneigh_entry does not need
to store a net pointer.
Let's remove it and net comparison for pneigh_entry.
We no longer need to pass net to pneigh_create(), pneigh_delete(),
and pneigh_lookup().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-14-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Now, neigh_table is ready to be namespacified.
Let's allocate per-netns neigh_table in neigh_table_register()
and call neigh_table_init() and neigh_sysctl_register() for it.
proc_create_seq_data() is changed to proc_create_net_data().
Since each netns has its own sysctl knobs, RTM_SETNEIGHTBL can
configure the default table param (ifindex==0) and GC parameters
per netns.
To avoid potential regression, all the default parameters under
/proc/sys/net/ipv{4,6}/neigh/default/, are inherited from init_net
by default.
This behaviour is controlled by a new sysctl knob,
net.core.neigh_inherit_init_net:
# sysctl net.core.neigh_inherit_init_net
net.core.neigh_inherit_init_net = 1
# sysctl net.ipv4.neigh.default.gc_thresh1
net.ipv4.neigh.default.gc_thresh1 = 128
# sysctl net.ipv4.neigh.default.gc_thresh1=129
net.ipv4.neigh.default.gc_thresh1 = 129
# unshare -n sysctl net.ipv4.neigh.default.gc_thresh1
net.ipv4.neigh.default.gc_thresh1 = 129
If it is turned off, all settings are reset in the new netns:
# sysctl net.core.neigh_inherit_init_net=0
net.core.neigh_inherit_init_net = 0
# unshare -n sysctl net.ipv4.neigh.default.gc_thresh1
net.ipv4.neigh.default.gc_thresh1 = 128
The next patch will remove other unnecessary net_eq().
Note that CONFIG_SYSCTL cannot be enabled without CONFIG_PROC_FS.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-13-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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We will allocate per-netns neigh_table in net->neigh_tables[].
Let's replace &nd_tbl with nd_table(net).
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-10-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Now, &arp_tbl and &nd_tbl are stored in net->neigh_tables[].
Let's use net->neigh_tables[] in neighbour.c and remove the
global neigh_tables[].
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-8-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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We will remove RTNL for neigh_add() and neigh_delete(), but they
are still serialised by per-protocol neigh_table.lock.
We can avoid contention by converting neigh_tables[] to per-netns,
but arp_tbl and nd_tbl are directly used in many places.
As a prep, let's store &arp_tbl and &nd_tbl in net->neigh_tables[].
We will replace such users with arp_table(net) and nd_table(net)
and then allocate per-netns neigh_table.
Note that nd_table() still returns &nd_tbl in case disable_ipv6_mod
is 1 because some buggy drivers use nd_tbl without checking it.
proc_create_net() is guarded with CONFIG_PROC_FS because it
returns NULL when =n and setup_net() fails and panic()s. Also
a later patch moves neigh_sysctl_register() under the guard.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-7-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Cross-merge networking fixes after downstream PR (net-7.3-rc2).
No conflicts, or adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Fraglist GRO and hardware GRO can create an fraglist of
HW-GRO packets. This cannot be segmented back into
the original form on TCP tethering scenario.
Avoid constructing such a GSO packet, by flushing an already
built fraglist GRO packet if a hardware GRO packet arrives.
Scenario (Tethering/Forwarding):
1.Driver submits a single TCP packet, P1. P1 is kept in the
gro_list as the first packet.
2. The driver submits a TCP GSO skb, P2. P2 has already aggregated
multiple TCP packets by HW_GRO, and its non-linear data is stored in
frags[].
3. P1 and P2 match the GRO rules, and since there is no local socket,
they are aggregated by skb_gro_receive_list(). The resulting skb,
P3, has a frag_list entry that still contains frags[]:
P3: [ Linear Data ] -> frag_list -> [ Linear Data ]
[ frag[1] ]
[ frag[2] ]
...
4. Later, tcp4_gso_segment() or tcp6_gso_segment() calls
skb_segment_list() to segment P3. However, skb_segment_list() only
segments the entries in frag_list. It does not segment the frags[]
inside P2, so P3 is not restored to the original packets, which leads
to IP fragmentation or packet drop in the following path.
Check skb_is_gso(skb) and current GRO method, make sure fraglist GRO
applies to consecutive non-GSO skb, others adopt regular GRO path.
Fixes: 8d95dc474f85 ("net: add code for TCP fraglist GRO")
Signed-off-by: Zhaoping Shu <zhaoping.shu@mediatek.com>
Signed-off-by: HW He <hw.he@mediatek.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260901082312.14596-1-zhaoping.shu@mediatek.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Commit 71338aa7d050c ("net: convert %p usage to %pK") which is from
2011 and changed the %p annotation for pointer to %pK. Back then the
default behaviour for %p was to print the pointer. The %pK modifier was
introduced to able to control the behaviour of specific pointer values
without changing the behaviour of %p for everyone. It was dedicated to
avoid leaking pointers via /proc.
There was also the idea to remove the check from formatting the string
and move to the open callback with some helpers but this did not happen.
Things changed over time. The default behaviour for %p is now to print a
hash pointer which does not leak the address but allows to correlate if
two pointers are equal.
The policy on %p is to not introduce new ones. This is somehow in
between since it already exists. The pointer are usually socket pointers
and I don't see any value in exposing them. Therefore I am following the
recommendation of removing them. Since their usage in /proc/ can be
considered ABI I replace the pointer with a 0.
Replace the %pK annotation with 0 value. Correct the spacing for the
cases where pointer is at the beginning.
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260901160345.eeknHmY2@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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ipv6_srh_rcv() runs with skb->data at the Segment Routing Header (SRH)
while skb_network_header() points at the IPv6 header.
When segments_left > 0, ipv6_srh_rcv() previously restored the skb->data
position by pushing sizeof(struct ipv6hdr), assuming the SRH immediately
followed the fixed IPv6 header. If another extension header (such as a
Hop-by-Hop options header) precedes the SRH, skb_network_offset()
remained negative.
This led to two problems:
1. During ip6_route_input(), fib6_rules_early_flow_dissect() invokes
__skb_flow_dissect() which passes the negative skb_network_offset()
to flow dissection, breaking BPF and C flow dissector logic.
2. If forwarded via ip6_forward() or redirected via act_mirred, downstream
handlers (like sch_fragment() or neighbour output) pass the negative
offset as an unsigned length, triggering OOB memcpy or buffer overflows.
Fix this by pushing -skb_network_offset(skb) before routing, ensuring
skb_network_offset(skb) is 0 for route lookup / flow dissection as well as
downstream forwarding. On the loopback path, pull skb_transport_offset(skb)
to restore skb->data to the SRH before looping back.
Fixes: 1ababeba4a21 ("ipv6: implement dataplane support for rthdr type 4 (Segment Routing Header)")
Reported-by: TencentOS Corvus AI <corvus@tencent.com>
Reported-by: Jun Yang <junvyyang@tencent.com>
Reported-by: Fourie Zhang <fouriezhang@tencent.com>
Closes: https://lore.kernel.org/netdev/20260817104128.22681-1-juny24602@gmail.com/
Closes: https://lore.kernel.org/netdev/20260827092345.2301937-1-fouriezhang@tencent.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828141727.2372570-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Currently, when ICMPv6 Packet Too Big and Redirect Message packets are
locally delivered and quote a UDP packet, an exception is only created
in the IPv6 exception cache if the kernel can match the UDP packet to an
existing socket.
This behavior allows off-path attackers to conduct a side-channel attack
on the exception cache in order to discover the ephemeral port used by a
connected UDP socket.
Commit 4785305c05b2 ("ipv6: use siphash in rt6_exception_hash()") and
commit a00df2caffed ("ipv6: make exception cache less predictible") tried
to mitigate such attacks by making it harder for attackers to discover
hash collisions in the exception cache and by randomizing the number of
exceptions a hash bucket can hold, respectively. Unfortunately, both of
the mitigations can be bypassed.
Instead, mitigate such attacks by always creating an exception, even
before trying to find a matching socket. Do that by calling
ip6_update_pmtu() and ip6_redirect(), the helpers used when the quoted
packet did not originate from a socket.
This means that guesses (right or wrong) from an off-path attacker will
always result in an exception being created or updated in the cache that
the attacker can observe.
Pass the ifindex of the ingress device and the default uid, in a similar
fashion to icmpv6_err(). Unlike IPv4, an oif of 0 would not match any
nexthop in ip6_redirect_nh_match() and no exception would be created in
response to a Redirect Message.
Note that this does not allow attackers to create exceptions that they
could not create before, as both helpers can already be reached with
little to no validation. For example, by sending an ICMPv6 error that
quotes an ICMPv6 Echo Reply or one that quotes a UDP source port that
matches a wildcard socket.
Also note that in the good case (matched socket) the above scheme comes
at the cost of an extra route lookup, as the no socket helpers perform
their own lookup before the one performed by ip6_sk_update_pmtu() /
ip6_sk_redirect(). When the two resolve to different nexthops, it also
results in two exceptions being created for the same destination IP. One
in the exception cache of the nexthop resolved by the no socket helpers
and another in the exception cache of the nexthop used by the socket.
Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache")
Cc: stable@vger.kernel.org
Reported-by: Amit Klein <aksecurity@gmail.com>
Reported-by: Noam Caspi <noam.caspi@mail.huji.ac.il>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260828192344.2596928-4-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When an ICMP Redirect Message is matched to a socket, both IPv4 and IPv6
verify that the source IP of the ICMP packet is the current gateway for
the quoted packet. Both also pass the socket's bound device as the
expected nexthop device.
The difference is that IPv4 treats "oif=0" as "any", whereas IPv6 always
requires an exact match (see ip6_redirect_nh_match()), since the gateway
address is usually a link-local address.
Therefore, when an IPv6 UDP/RAW socket is not bound to a device, the
above verification fails and an exception is not created. This also
happens when the socket is bound to a VRF, as l3mdev_update_flow()
resets the oif to 0.
Fix this by passing the ifindex of the ingress device as the expected
nexthop device. This is consistent with the existing callers of
ip6_redirect(). Note that for ICMPv6 Redirect Message packets the VRF
driver does not reset skb->dev to the VRF device, so skb->dev is
correct, even when it is a VRF port.
Fixes: b55b76b22144 ("ipv6:introduce function to find route for redirect")
Cc: stable@vger.kernel.org
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828192344.2596928-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Shuangpeng Bai reported a KASAN slab-use-after-free in
ip6gre_tunnel_xmit().
The precise KASAN bug was caused by ip6_tnl_xmit() consuming the
skb during headroom expansion and returning an error, while
ip6gre_tunnel_xmit() still held the stale pointer and called
skb_tunnel_info_txcheck(skb) at tx_err. That specific bug was fixed by
commit 87f21b59ddc6 ("ip6_tunnel: use skb_cow_head() in ip6_tnl_xmit()").
However, calling skb_tunnel_info_txcheck(skb) at the tx_err label
after the transmission attempt remains problematic:
Downstream helpers like ip6_tnl_xmit() call skb_scrub_packet(),
which drops the skb's metadata_dst before transmission. If an error
occurs later during transmit, inspecting skb at tx_err sees a scrubbed
dst and misclassifies tx_errors vs tx_dropped.
Commit e5f7e211b6aa ("ip6gre: avoid tx_error when sending MLD/DAD on
external tunnels") already handled this correctly in
ip6erspan_tunnel_xmit() by checking and caching tun_info before
transmit.
Align ip6gre_tunnel_xmit() with ip6erspan_tunnel_xmit() by caching
tun_info before xmit and checking it at tx_err.
Fixes: e5f7e211b6aa ("ip6gre: avoid tx_error when sending MLD/DAD on external tunnels")
Reported-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Closes: https://lore.kernel.org/netdev/20260819062224.3197349-1-shuangpeng.kernel@gmail.com/
Cc: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828103731.1951815-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
If a multicast group timer has expired but the delayed work has
not yet run to clear MAF_TIMER_RUNNING, expires - jiffies produces
a negative value.
Because unsigned arithmetic was used with jiffies_to_clock_t(),
expires - jiffies underflows to a huge value and reports invalid
timer durations in /proc/net/igmp6.
Use jiffies_delta_to_clock_t() with a signed long delta to properly
cap expired deltas to 0, matching IPv4 igmp_mc_seq_show() and commit
a399a8053164 ("time: jiffies_delta_to_clock_t() helper to the rescue").
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828084531.1826790-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Several places in net/ipv6/mcast.c update RCU-protected lists
(np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer
assignments instead of rcu_assign_pointer():
1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did:
*map = ma->next;
without rcu_assign_pointer() while concurrent readers traverse
idev->mc_list locklessly under rcu_read_lock().
2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group
from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and
np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing
with lockless readers in inet6_mc_check().
3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to
np->ipv6_mc_list via raw assignment before publishing mc_lst.
4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers
passed into rcu_assign_pointer() lacked explicit dereference helpers.
Fix these by consistently using rcu_assign_pointer() along with
mc_dereference() / sock_dereference().
Fixes: 456b61bca8ee ("ipv6: mcast: RCU conversion")
Fixes: 88e2ca308094 ("mld: convert ifmcaddr6 to RCU")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828084531.1826790-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When joining a multicast group, if a report work is already pending
(e.g. scheduled by a query or a previous join), igmp6_join_group()
cancels the delayed work and recalculates the delay:
if (cancel_delayed_work(&ma->mca_work)) {
refcount_dec(&ma->mca_refcnt);
delay = ma->mca_work.timer.expires - jiffies;
}
Unlike igmp6_group_queried(), igmp6_join_group() did not check
if delay >= interval. This leads to two issues:
1. If the timer has already expired (timer.expires <= jiffies), the
stale expiry is reused by mod_delayed_work(), causing the second
unsolicited report to fire on the very next tick without a
randomized delay.
2. If the timer was originally armed by a query with a large
maximum response delay, delay could exceed
unsolicited_report_interval(ma->idev).
Fix this by initializing delay to unsolicited_report_interval(ma->idev)
and re-randomizing it with get_random_u32_below(interval) when
delay >= interval, mirroring the logic in igmp6_group_queried().
Fixes: 2d9a93b4902b ("mld: convert from timer to delayed work")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://patch.msgid.link/20260828084531.1826790-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
pmc->sflist is read locklessly under rcu_read_lock() by
inet6_mc_check() during packet reception in the UDP and RAW
multicast receive paths.
ip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place
when adding or removing a source filter. Additionally, when expanding
the filter buffer, newpsl was published via rcu_assign_pointer()
before writing the new source into the array.
Because 16-byte struct in6_addr writes are not atomic and array
shifting is not synchronized with RCU readers, concurrent readers in
inet6_mc_check() could read torn IPv6 addresses or observe
duplicated/missed source entries.
Fix this by switching ip6_mc_source() to copy-on-write RCU updates:
allocate and fully populate newpsl before publishing it via
rcu_assign_pointer(), and reclaim the old filter via kfree_rcu(),
matching ip6_mc_msfilter().
Also remove the now unused IP6_SFBLOCK macro.
Fixes: 882ba1f73c06 ("mld: convert ipv6_mc_socklist->sflist to RCU")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828084531.1826790-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
When removing a source filter whose count reaches zero, ip6_mc_del1_src()
unlinks psf from pmc->mca_sources. If the filter was previously active,
the code moved psf directly into pmc->mca_tomb by updating psf->sf_next.
Because pmc->mca_sources is traversed locklessly under RCU (e.g. by
ipv6_chk_mcast_addr()), mutating psf->sf_next before a grace period
elapses diverts concurrent readers to the tombstone list. Consequently,
readers miss remaining active sources in pmc->mca_sources and improperly
examine deleted tombstone entries.
Fix this by allocating a new tombstone node for pmc->mca_tomb (as done
in sf_setstate()) and retiring the original psf via kfree_rcu().
Fixes: 4b200e398953 ("mld: convert ip6_sf_list to RCU")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260828084531.1826790-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for net:
1) Use DEBUG_NET_WARN_ON_ONCE() instead of WARN_ON() from the tproxy
datapath, a recent bug found a way to reach WARN_ON from datapath
due to insufficient validation of xt_TPROTO checkentry.
From Fernando F. Mancera.
2) Similar to previous patch to replace WARN_ON_ONCE by
DEBUG_NET_WARN_ON_ONCE() for connlimit. Not known issue, but
since this patch has been around for a while, let's merge it.
Also from Fernando.
3) Move nf_tables harware offload commit path after chain blob
and audit to reduce chances of leaving the hardware in
inconsistent state.
4) Add missing vzeroupper to nf_tables pipapo AVX2 to address
performace degradation to later user of SSE code,
from Eric Biggers.
5) Remove pr_debug() in x_tables extensions, a recent bogus found a
way to print a unsanitized string in xt_IDLETIMER, many of these
pr_debug() calls are there for historical reasons.
6) Use pr_info_ratelimited() in x_tables .checkentry.
7) Fix an imbalance in module refcount due to incorrect override
expression logic with sets. Remove unnecessary clone in control
plane, use the existing expressions provided by set or dynset
expression. Release override expressions only.
8) Tigthen nf_tables device name removal, it is possible to remove
prefix strings with exact device name. From Fernando F. Mancera.
9) Set on the set dead bit earlier, otherwise it is possible to
call .commit on deleted sets. This also addresses the
re-introduction of a bug.
* tag 'nf-26-08-27' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nf_tables: remove leftover set_update_list
netfilter: nf_tables: set on dead bit when performing early element removal
netfilter: nf_tables: skip double clone set expressions on element insert
netfilter: x_tables: replace pr_{info,err}() by pr_info_ratelimited()
netfilter: x_tables: remove pr_debug
netfilter: nft_set_pipapo_avx2: add missing vzeroupper
netfilter: nf_tables: move hardware offload step after building the chain blob
netfilter: conncount: use DEBUG_NET_WARN_ON_ONCE on reaching count limit
netfilter: tproxy: use DEBUG_NET_WARN_ON_ONCE for protocol fallbacks
====================
Link: https://patch.msgid.link/20260827141733.423453-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
Remove pr_debug() for these xtables extensions, these have no use
these days. Still, turn pr_debug() into pr_info_ratelimited() in the
.checkentry path since this helps provide a hint via dmesg in legacy
iptables.
Exception is xt_IDLETIMER in the module init path, where pr_err() is
used.
Add missing pr_fmt() definition in xt_REDIRECT, xt_NETMAP and
xt_MASQUERADE.
Add missing \n to several pr_debug() that were translated to use
pr_info_ratelimited().
Link: https://patch.msgid.link/cover.1786933680.git.rakukuip@gmail.com/
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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|
Replace WARN_ON calls with DEBUG_NET_WARN_ON_ONCE in the default switch
blocks of nf_tproxy_get_sock_v4 and v6. Unsupported transport protocols
are already safely handled by returning a NULL socket pointer. This
prevents unnecessary system panics when panic_on_warn=1 is enabled in
production systems.
Link: https://patch.msgid.link/cover.1786968834.git.zhilinz@nebusec.ai/
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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|
decap_and_validate() pulls the outer SRv6 headers and makes the inner
packet the skb network header. The IPv6 control block still contains
values collected while parsing the outer packet, including nhoff and
extension-header flags.
End.DX6 and End.DT6 route the inner IPv6 packet directly to the IPv6
input path. An unprivileged user can reach End.DT6 from a user and net
namespace by installing a local SID and injecting an outer packet with
Hop-by-Hop and Destination Options headers followed by an SRH and a
minimal inner IPv6 packet.
The outer extension headers leave a large nhoff in IP6CB. After
decapsulation, ip6_protocol_deliver_rcu() uses that stale offset on the
inner packet and reads beyond the skb head. KASAN reports:
BUG: KASAN: slab-out-of-bounds in ip6_protocol_deliver_rcu
ip6_protocol_deliver_rcu+0x1118/0x1450
ip6_input_finish+0x11b/0x240
seg6_local_input_core+0xed/0x2e0
lwtunnel_input+0x1e9/0x4e0
ipv6_rthdr_rcv+0x525f/0x6c50
ip6_protocol_deliver_rcu+0xcb7/0x1450
Before clearing IP6CB for an inner IPv6 packet, save its incoming
interface index and L3 slave state. Restore both after the clear and set
nhoff to the inner IPv6 base-header nexthdr field.
Use IP6CB(skb)->iif rather than skb->skb_iif because VRF processing can
replace skb_iif with the L3 master while IP6CB keeps the receiving
interface. Preserve IP6SKB_L3SLAVE for the same reason.
Fixes: d7a669dd2f8b ("ipv6: sr: add helper functions for seg6local")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
On the out-of-place output path (esp->inplace == false) ESP rewrites the
skb frag array: esp_output_head() appends a trailer frag and
esp_output_tail() replaces the frags with a destination page, both
referenced with get_page().
When the skb carries zerocopy managed frags (SKBFL_MANAGED_FRAG_REFS) the
payload frags are owned by the ubuf and must not be referenced or
unreferenced individually, but ESP mutates the frag array without ever
downgrading the skb. This breaks the managed-frag invariant two ways:
- esp_ssg_unref() walks the source scatterlist and drops a page
reference for every frag, including the ubuf-owned payload frags,
pushing their refcount below the GUP pin bias while the pages are
still pinned, i.e. a use-after-free of the zerocopy pages;
- esp_output_tail() installs its destination page as frag 0 with
get_page() but leaves SKBFL_MANAGED_FRAG_REFS set, so
skb_release_data() takes the skip_unref branch and never drops that
reference, leaking the x->xfrag page at packet rate.
Fix this the way every other frag-mutating site does (__ip_append_data(),
__ip6_append_data(), tcp_sendmsg_locked()) and call
skb_zcopy_downgrade_managed() before ESP touches the frag array: it takes
a real reference on each existing frag and clears SKBFL_MANAGED_FRAG_REFS,
so the per-frag unref in esp_ssg_unref() and the frag release in
skb_release_data() are both balanced and no mixed-ownership frag array is
left behind.
Fixes: 753f1ca4e1e5 ("net: introduce managed frags infrastructure")
Signed-off-by: Maher Azzouzi <maherazz04@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
|
|
tcp_select_initial_window() assumes that callers never pass an MSS
smaller than 1, but route-derived advmss values can violate that
assumption.
A too-small explicit RTAX_ADVMSS is one way to get there, but it is not
the only one. The same divide-by-zero can also be reached through the
"default advmss" path when RTAX_ADVMSS is left at 0 and the effective
advmss is later driven down by route MTU and min_adv_mss.
Introduce a tcp_dst_advmss() helper that clamps route advmss to
TCP_MIN_MSS before TCP consumes it, and use it in the TCP paths that
derive advmss from dst metrics. This keeps the effective MSS from
dropping to zero before tcp_select_initial_window() rounds the receive
window.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Yong Wang <edragain@163.com>
Signed-off-by: Ren Wei <weir@nebusec.ai>
Link: https://patch.msgid.link/251eaf8277fa7c66364c9815c5da01662d269181.1787074852.git.edragain@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
End.DX4 and End.DT4 decapsulate an IPv4 packet through
decap_and_validate() and send it directly to IPv4 routing. The inner
packet therefore bypasses ip_rcv_core(), which normally clears IPCB
before IPv4 interprets skb->cb.
The skb instead retains IP6CB data from the outer packet. IP6CB and
IPCB use the same skb->cb storage, so IP6CB(skb)->lastopt overlaps
IPCB(skb)->opt.optlen and srr, while IP6CB(skb)->nhoff overlaps rr and
ts.
The sender can make the stale optlen byte nonzero with a valid outer
extension-header chain. The reproducers put an eight-byte Destination
Options header immediately after the 40-byte IPv6 header and before the
Segment Routing Header. ipv6_destopt_rcv() records the sender-controlled
Destination Options offset in both lastopt and nhoff, setting them to
40. On the reproduced little-endian x86-64 kernel, IPv4 therefore sees
optlen = 40 and rr = 40.
Both tcp_v4_save_options() and __ip_options_echo() skip option copying
when optlen is zero. Here optlen is 40, so the TCP SYN path allocates
room for 40 bytes of option data and calls __ip_options_echo(). The
stale rr value makes that function read inner packet byte 41 as the
Record Route option length. The reproducers set that sender-controlled
byte to 255, so __ip_options_echo() copies 255 bytes into the 40-byte
option-data area.
Separate End.DX4 and End.DT4 reproducers on the unpatched v7.2-rc5
kernel both produced:
BUG: KASAN: slab-out-of-bounds in __ip_options_echo()
Write of size 255
The relevant End.DX4 call path is:
__ip_options_echo
tcp_v4_route_req
tcp_conn_request
tcp_v4_conn_request
tcp_rcv_state_process
tcp_v4_do_rcv
tcp_v4_rcv
ip_protocol_deliver_rcu
ip_local_deliver_finish
ip_local_deliver
input_action_end_dx4_finish
input_action_end_dx4
The relevant End.DT4 call path is:
__ip_options_echo
tcp_v4_route_req
tcp_conn_request
tcp_v4_conn_request
tcp_rcv_state_process
tcp_v4_do_rcv
tcp_v4_rcv
ip_protocol_deliver_rcu
ip_local_deliver_finish
ip_local_deliver
input_action_end_dt4
tcp_v4_save_options() is inlined into the tcp_v4_route_req() path, so
it does not appear as a separate frame.
When decap_and_validate() handles IPPROTO_IPIP, save the ingress
interface from IP6CB, clear IPCB, and restore the saved value. Doing
this in the common decapsulation path covers End.DX4, End.DT4, and
End.DT46's IPv4 arm.
Use IP6CB(skb)->iif rather than skb->skb_iif. These actions run after
l3mdev processing, which can replace skb_iif with the L3 master;
IP6CB iif still records the receiving interface set at IPv6 ingress.
Fixes: 891ef8dd2a8d ("ipv6: sr: implement additional seg6local actions")
Cc: stable@vger.kernel.org
Suggested-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Signed-off-by: Kyle Zeng <kylebot@openai.com>
Co-developed-by: David Lee <david.lee@trailofbits.com>
Signed-off-by: David Lee <david.lee@trailofbits.com>
Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Link: https://patch.msgid.link/20260817085839.946321-1-david.lee@trailofbits.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
IPv6 input attaches a non-refcounted (NOREF) dst to skbs under RCU.
When an ingress multicast packet misses MFC lookup,
ip6mr_cache_unresolved() places the skb onto the unresolved queue,
escaping the receive-side RCU grace period.
If the underlying route is deleted and freed, and the MFC queue is later
resolved with a wrong parent interface, ip6_mr_forward() invokes
ip6mr_cache_report(..., MRT6MSG_WRONGMIF), which executes
dst_clone(skb_dst(pkt)) on the freed dst entry, triggering a slab
use-after-free.
Report packets queued to mroute6_sk (a raw socket) and netlink
notifications do not require an attached dst entry.
Fix this by:
1. Removing dst_clone() in ip6mr_cache_report() and ensuring report skbs
do not hold a dst.
2. Dropping skb_dst before queuing unresolved skbs in
ip6mr_cache_unresolved(), matching the fact that multicast
forwarding resolves outgoing routes anew via ip6_route_output().
Fixes: 67f415dd2906 ("ipv6: convert rx data path to not take refcnt on dst")
Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Hangbin Liu <liuhangbin@kylinos.cn>
Link: https://patch.msgid.link/20260818172755.4083692-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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rt6_multipath_rebalance() calculates the total eligible nexthop weight
in one pass and programs upper bounds in a second pass. Since
RTM_NEWROUTE is RTNL-free, a concurrent
ignore_routes_with_linkdown update can make the first pass return zero
while the second sees an eligible nexthop, causing
rt6_upper_bound_set() to divide by zero.
UBSAN: division-overflow in net/ipv6/route.c:4845:17
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
rt6_upper_bound_set() net/ipv6/route.c:4845
rt6_multipath_rebalance()
fib6_add_rt2node()
ip6_route_multipath_add()
inet6_rtm_newroute()
Skip upper-bound calculation when the first pass reports a zero total.
This respects the lock-free performance considerations here and solves
insecure scenarios.
Fixes: bd11ff421d36 ("ipv6: Get rid of RTNL for SIOCDELRT and RTM_DELROUTE.")
Reported-by: AutonomousCodeSecurity@microsoft.com
Reported-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Reported-by: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Signed-off-by: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260817013237.2797-1-blbllhy@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
ipv6_rpl_srh_rcv() dereferences idev from __in6_dev_get() without a NULL
check when reading idev->cnf.rpl_seg_enabled.
When the device's MTU drops below IPV6_MIN_MTU, addrconf_ifdown() clears
dev->ip6_ptr through RCU_INIT_POINTER(). A packet that passed the idev
check in ip6_rcv_core() can then reach ipv6_rpl_srh_rcv() with
dev->ip6_ptr already NULL.
Reproduced by flooding the receiving interface with ping6 traffic while
flapping its MTU between 1500 and 1200:
BUG: KASAN: null-ptr-deref in ipv6_rpl_srh_rcv+0xb3/0x1070
Read of size 4 at addr 00000000000006b4 by task ping6/394
CPU: 2 UID: 0 PID: 394 Comm: ping6 Not tainted 7.2.0-rc7-micro-vm-dev-00095-g24ef02f934ee #240 PREEMPT(full)
Call Trace:
<IRQ>
kasan_report+0xc6/0x100
ipv6_rpl_srh_rcv+0xb3/0x1070
ip6_protocol_deliver_rcu+0x759/0x9a0
ip6_input_finish+0xa8/0x1b0
ip6_input+0xe1/0x490
ipv6_rcv+0x33d/0x460
__netif_receive_skb_one_core+0xd6/0x130
process_backlog+0x2cc/0xa00
__napi_poll.constprop.0+0x56/0x270
net_rx_action+0x327/0x730
handle_softirqs+0x11e/0x630
do_softirq+0xb3/0xf0
</IRQ>
Both ipv6_rpl_srh_rcv() and ipv6_srh_rcv() are called only from
ipv6_rthdr_rcv(), which already has an idev lookup.
Fix the NULL dereference on the RPL path by checking idev in
ipv6_rthdr_rcv(), before it calls either function. The callees take idev as
an argument and no longer call __in6_dev_get(), so the packet is now
dropped in one place, with SKB_DROP_REASON_IPV6DISABLED on both paths.
Fixes: 8610c7c6e3bd ("net: ipv6: add support for rpl sr exthdr")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Tested-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260817132644.2223-1-andrea.mayer@uniroma2.it
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The MSS a host puts in its SYN tells the peer how big a segment it may
send us. Right now we can shrink it with a PMTU we learned on our own
send path, which is the wrong direction entirely.
On asymmetric paths this bites - think DSR load balancers, where the
request side goes through a smaller-MTU overlay. We learn a small PMTU
going out, then advertise a small MSS, and the peer stays capped for the
whole connection even though its path back to us is wide. MSS only shows
up in the SYN and never grows back.
On symmetric paths we lose nothing by dropping it either: the peer runs
its own PMTU discovery and usually already knows the real path MTU.
So work out the advertised MSS from the configured route or device MTU
and ignore the learned PMTU. Our send side is unchanged, still clamped by
tcp_current_mss(). Add ip_dst_mtu_configured()/ip6_dst_mtu_configured()
and use them from the two default_advmss() paths.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 164a5e7ad531 ("ipv4: ipv4_default_advmss() should use route mtu")
Cc: stable@vger.kernel.org
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260815070413.294559-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
Steffen Klassert says:
====================
pull request (net): ipsec 2026-08-18
1) xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full
Tighten the secpath-depth check so a full chain can't write
past xvec[].
2) Add and revert "esp: do not unref managed frag pages in esp_ssg_unref()"
The patch does not fully fully resolve the issue, a corrected version
will follow.
3) xfrm: espintcp: fix UAF during close
Synchronize espintcp close with the xfrm_trans_reinject work
queue so the freed socket message isn't dereferenced again.
4) xfrm: drop ESP-in-TCP packets with no ingress device
Drop queued ESP-in-TCP records whose saved ingress device has
gone away, avoiding a NULL device deref in the XFRM input path.
5) xfrm: avoid lock inversion in nat keepalive work
Split the NAT keepalive walk into a reference-collection phase
and a per-state lock phase to break the AB-BA with state removal.
This patch has some issues that are fixed with a followup patch.
6) xfrm: Fix skb double-free in xfrm_dev_direct_output()
Stop freeing the skb unconditionally in xfrm_dev_direct_output(),
letting local_out()'s result indicate when ownership has moved on.
7) xfrm: ah6: validate routing header segments_left
Validate the segments_left/hdrlen invariant before rearranging
the routing-header addresses, avoiding an OOB memmove on
malformed HDRINCL packets.
8) xfrm: fix xfrm_state_construct() auth-trunc leak
Detect an already-attached auth-trunc allocation by the pointer
rather than inferring it from the algorithm id, so a prior
attach isn't overwritten and lost.
9) xfrm: bound nat keepalive state collection
Replace the per-state allocation in the NAT keepalive walk
with a fixed-size batch that drains under BH-disabled locking
and resumes from the cursor, bounding the worker's memory.
* tag 'ipsec-2026-08-18' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: bound nat keepalive state collection
Revert "esp: do not unref managed frag pages in esp_ssg_unref()"
xfrm: fix xfrm_state_construct() auth-trunc leak
xfrm: ah6: validate routing header segments_left
xfrm: Fix skb double-free in xfrm_dev_direct_output()
xfrm: avoid lock inversion in nat keepalive work
xfrm: drop ESP-in-TCP packets with no ingress device
xfrm: espintcp: fix UAF during close
esp: do not unref managed frag pages in esp_ssg_unref()
xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full
====================
Link: https://patch.msgid.link/20260818092920.653034-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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rt6_nh_dump_exceptions() uses hlist_for_each_entry() to iterate over
RCU-protected exception lists. The caller holds rcu_read_lock(), but does
not hold rt6_exception_lock, so rt6_insert_exception() can concurrently
add an entry with hlist_add_head_rcu().
KCSAN reports this race (irrelevant details omitted):
==================================================================
BUG: KCSAN: data-race in rt6_insert_exception / rt6_nh_dump_exceptions
write (marked) to 0xffff8a7c44c59620 of 8 bytes by interrupt on cpu 5:
rt6_insert_exception+0x3bb/0x760
__ip6_rt_update_pmtu+0x4fe/0x750
ip6_sk_update_pmtu+0x19a/0x3b0
udpv6_err+0x3ff/0x800
icmpv6_notify+0x1e1/0x440
icmpv6_rcv+0x8c0/0xab0
ip6_protocol_deliver_rcu+0x616/0x840
ip6_input_finish+0xb9/0x160
...
entry_SYSCALL_64_after_hwframe+0x77/0x7f
read to 0xffff8a7c44c59620 of 8 bytes by task 549 on cpu 14:
rt6_nh_dump_exceptions+0xb3/0x260
rt6_dump_route+0x53e/0x5f0
fib6_dump_node+0x6d/0xf0
fib6_walk_continue+0x290/0x2d0
fib6_dump_table+0x28d/0x360
inet6_dump_fib+0x37d/0x620
rtnl_dumpit+0x7b/0xd0
netlink_dump+0x3ae/0x7e0
...
entry_SYSCALL_64_after_hwframe+0x77/0x7f
4 locks held by dumper/549:
...
#1: (rcu_read_lock){....}-{1:3}, at: inet6_dump_fib+0x88/0x620
#2: (&tb->tb6_lock){+.-.}-{3:3}, at: fib6_dump_table+0x1e9/0x360
#3: (rcu_read_lock){....}-{1:3}, at: rt6_dump_route+0x483/0x5f0
value changed: 0xffff8a7c44e05700 -> 0xffff8a7c45d60100
Reported by Kernel Concurrency Sanitizer on:
CPU: 14 UID: 0 PID: 549 Comm: dumper Not tainted
7.2.0-rc7-virtme #38 PREEMPT(lazy)
...
Use hlist_for_each_entry_rcu() to safely iterate over the exception list.
Fixes: 1e47b4837f3b ("ipv6: Dump route exceptions if requested")
Cc: stable@vger.kernel.org
Signed-off-by: Yuyang Huang <sigefriedhyy@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260815084651.69477-1-sigefriedhyy@gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Merge in late fixes in preparation for the net-next PR.
Conflicts:
drivers/dpll/dpll_core.c
drivers/dpll/dpll_netlink.c
33f016b23a219 ("dpll: fix NULL deref in dpll_device_ops() during teardown race")
b1d0c412088e3 ("dpll: add STATE_CONNECTED_OVERRIDE pin capability")
https://lore.kernel.org/aoR9YYY2P5--3x0N@sirena.org.uk
https://lore.kernel.org/aoR9VmKllVGwmQn_@sirena.org.uk
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
IPv4 and IPv6 input preserve an skb->sk association installed by
bpf_sk_assign() so that local delivery can use the selected socket under
RCU. Both address families can also prefetch a socket in UDP early demux.
In both paths (BPF and UDP early demux) a reference is not guaranteed to
be held on the socket.
When a multicast packet is not locally deliverable, IPv6 hands the
original skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the
original skb when local delivery is not needed. Either path can put the
skb on an unresolved multicast route queue or forward it after the
receive-side RCU section ends.
After the prefetched socket is destroyed, a later skb free invokes
sock_pfree() and dereferences the stale skb->sk. Orphan the skb before
each non-local multicast forwarding path. Local delivery retains the
original skb; the existing skb_clone() calls provide multicast forwarding
with a socket-free clone.
Fixes: cf7fbe660f2d ("bpf: Add socket assign support")
Fixes: 08842c43d016 ("udp: no longer touch sk->sk_refcnt in early demux")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/0c52eb3d7532aaf8bccf37e0f7c922143c639735.1786552223.git.zhilinz@nebusec.ai
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
IP tunnel devices derive their advertised needed_headroom from lower
output devices. A stack of user-created devices can make the derived
value larger than the 16-bit skb header offsets can represent. Once IP
output reserves it, skb head expansion can wrap those offsets.
The runtime transmit path already caps a growing needed_headroom at 512.
Apply the same cap when tunnel configuration publishes needed_headroom
derived from a lower output device.
Capping the advertised value is safe: IP tunnel transmit still expands
the skb when a packet needs more headroom. A nonsensical stacked
configuration can therefore incur an extra reallocation, but it cannot
publish an unbounded reservation to upper layers.
Fixes: 1a37e412a022 ("net: Use 16bits for *_headers fields of struct skbuff")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/ba04a1fd6bfae2377607fad5d8f80f7eb80fd4c4.1786542637.git.zhilinz@nebusec.ai
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
ip6gre_tnl_link_config_route() accumulates the lower device's hardware
header length into dev->hard_header_len whenever header_ops is set. This
is incorrect for both users of header_ops.
ip6gretap and ip6erspan have a fixed Ethernet hardware header length.
For an NBMA ip6gre tunnel, ip6gre_header() creates only the GRE header,
the optional FOU or GUE header, and the outer IPv6 header. The lower
device header is headroom needed later, not part of the tunnel device's
hardware header.
Keep the lower device header in needed_headroom. Set hard_header_len to
the tunnel header length only for ARPHRD_IP6GRE devices with header_ops,
and leave the fixed Ethernet header length unchanged for tap and erspan
devices.
Fixes: 832ba596494b ("net: ip6_gre: set dev->hard_header_len when using header_ops")
Cc: stable@vger.kernel.org
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/64b46542bbe1701f07702aaa50273e2a87903db5.1786542637.git.zhilinz@nebusec.ai
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
xfrm6_local_rxpmtu() and xfrm6_local_error() dereference skb->sk as if it
always pointed at a full IPv6 socket.
That is not guaranteed. TCP SYN-ACK skbs can be owned by a
TCP_NEW_SYN_RECV request_sock while the output path itself is driven by the
full listener. If rerouting selects an IPv6 XFRM tunnel route with a lower
MTU, the local PMTU/error handling path can reach these callbacks with that
mini-socket still attached to the skb.
The callbacks then miscast the request socket as a full inet/IPv6 socket and
can read beyond the request_sock allocation when they access inet_sock or
ipv6_pinfo state.
Resolve the owner with skb_to_full_sk() in both callbacks and bail out when
no full socket is attached. This matches the surrounding XFRM IPv6 PMTU/error
logic, which already reasons about full sockets with skb_to_full_sk().
Fixes: dd767856a36e ("xfrm6: Don't call icmpv6_send on local error")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
|
|
ip6_tnl_xmit() may need to expand headroom before it can push the
outer IPv6 and optional encap headers. It currently does that with
skb_realloc_headroom(), copies skb->sk ownership, consumes the original
skb, and then continues processing with the replacement skb kept only in
its local variable.
That is safe only if the helper cannot fail afterwards. But this helper
still has post-reallocation error exits. collect_md tunnels reject
non-NONE encap after the replacement, and ip6_tnl_encap() can also fail
later. In those cases the helper returns an error to its callers while
the caller still only has the original skb pointer.
Both ip6_tnl_start_xmit() and the IPv6 GRE paths free the caller skb on
error, so they can end up freeing an skb that ip6_tnl_xmit() already
consumed.
Use skb_cow_head() instead. It provides the required headroom and
writability without privately replacing the caller-owned skb, so later
error returns cannot leave callers with a stale pointer.
The Ethernet users, ip6gretap and ip6erspan, clear IFF_TX_SKB_SHARING
and already call skb_cow_head() before entering ip6_tnl_xmit(). They do
not rely on the removed skb_shared() reallocation. This also makes the
IPv6 tunnel path consistent with ip_tunnel_xmit().
Fixes: 058214a4d1df ("ip6_tun: Add infrastructure for doing encapsulation")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Link: https://patch.msgid.link/30807a062ccc5c9c8a5ec2c5eb805ef279c50bdd.1786452593.git.zhilinz@nebusec.ai
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
ip6_finish_output2() caches a pointer to the IPv6 destination
address (daddr) before invoking lwtunnel_xmit(). The LWT-BPF
transmit path or other encapsulation operations within
lwtunnel_xmit() can reallocate the skb head, freeing the memory
that daddr points to. When lwtunnel_xmit() returns
LWTUNNEL_XMIT_CONTINUE, the function continues to use the stale
daddr pointer to compute the nexthop and to look up or create the
neighbour entry. This results in a use-after-free read, which can
leak sensitive kernel data, pollute the neighbour table with
arbitrary values, misdirect traffic, or crash the system.
Fix this by re-fetching the IPv6 header and the destination
address pointer after lwtunnel_xmit() returns
LWTUNNEL_XMIT_CONTINUE, ensuring that the subsequent nexthop
computation and neighbour lookup operate on valid memory.
Fixes: e415ed3a4b8b ("ipv6: use skb_expand_head in ip6_finish_output2")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Luxiao Xu <rakukuip@gmail.com>
Signed-off-by: Ren Wei <weir@nebusec.ai>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/4aa3f53bc44e79572c6dd2340ec7b68ef1a3d87d.1786516730.git.rakukuip@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
This reverts commit 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80.
The patch does not fix the issue completely, so revert for
now and wait for an updated version.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
|
|
For IPv4 ERSPAN:
In erspan_xmit(), the driver clears IP_TUNNEL_SEQ_BIT (for version 0)
and IP_TUNNEL_KEY_BIT directly in the shared tunnel->parms.o_flags
structure. Since transmit paths can run locklessly and concurrently,
this leads to a data race.
Furthermore, modifying tunnel->parms.o_flags permanently alters the
tunnel configuration. To work around this, erspan_fill_info() (which
reports config to userspace) was setting IP_TUNNEL_KEY_BIT back. If
erspan_fill_info (running under RTNL) and erspan_xmit (running locklessly)
race, erspan_xmit might see IP_TUNNEL_KEY_BIT set when it shouldn't,
leading to GRE header corruption (injecting a key field into the ERSPAN
GRE header).
Fix this by:
1) Passing flags as an argument to __gre_xmit().
2) Using local stack flags in ipgre_xmit(), gre_tap_xmit(), and erspan_xmit()
to prevent TOCTOU data races with concurrent configuration updates,
and passing them to __gre_xmit().
3) Removing the racy modification of t->parms.o_flags in erspan_fill_info().
4) Forcing IP_TUNNEL_KEY_BIT in the reported flags for ERSPAN locally
in ipgre_fill_info().
For IPv6 ERSPAN:
ip6erspan_tunnel_xmit() was locklessly clearing IP_TUNNEL_KEY_BIT in
t->parms.o_flags even though it does not use these flags for building
the GRE header (it uses local flags). This permanently corrupts the
configuration and races with ip6gre_fill_info() which reads it.
Remove the redundant and racy modification.
This should remove false sharing in a fast path.
Add const qualifiers in ipgre_fill_info(), erspan_fill_info()
and ip6gre_fill_info() to clarify that these methods are not
supposed to write any live parameters.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260812142257.21283-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next
Pablo Neira Ayuso says:
====================
Netfilter updates for net
This includes an enhancement to detect ct memleaks easier via
DEBUG_NET and flowtable preparation patches for IPv4 over IPV6
and vice-versa. This also includes a fix for the nft_ct custom
expectation support.
1) Add DEBUG_NET_WARN_ON_ONCE to nf_ct_set() to spot ct memleaks.
2) Pass struct net_device_path_ctx to dev_fill_forward_path() to
make it easier to pass more parameters to this function.
From Lorenzo Bianconi.
3) Add ether_type field to net_device_path context structucture.
4) Rename tun.l3_proto field to tun.inner_proto.
5) Rename ctx.tun.proto to ctx.tun.inner_proto.
6) Store ether_type in flowtable context.
7) Move IPv4 and IPv6 xmit path to a helper function.
8) Move encapsulation header parser out of the flowtable lookup
function.
9) Rework nft_ct custom expectation support to address a possible
reallocation of ct extension area while expectation list also
contains expectations. Move datapath to a ct helper to fix it.
10) Ensure timeout is always lowered for the non-closing RST case
in the TCP connection tracking.
11) Bail out when inserting already dead expectation, this should
not ever happen, hence report it via DEBUG_NET.
12) Comestic updates for improving the conntrack selftest dump and
flush userspace program, from Qingshuang Fu.
* tag 'nf-next-26-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
selftests: netfilter: conntrack_dump_flush: remove unused variables and fix typo
netfilter: nf_conntrack_expect: bail out on insert dead expectations
netfilter: conntrack: always lower timeout for non-closing RST packets
netfilter: nft_ct: move custom expectation support to helper
netfilter: flowtable: detach layer 2 encapsulation parser from lookup
netfilter: flowtable: move ipv4 and ipv6 xmit path to function
netfilter: flowtable: store ethertype in flowtable context
netfilter: flowtable: rename ctx.tun.proto to ctx.tun.inner_proto
netfilter: flowtable: rename tun.l3_proto to tun.inner_proto
net: netfilter: add ether_type to net_device_path_ctx and use it
net: pass net_device_path_ctx to dev_fill_forward_path()
netfilter: add DEBUG_NET_WARN_ON_ONCE to skb_set_nfct()
====================
Link: https://patch.msgid.link/20260810194015.932627-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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