ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the
quoted inner IPv6 packet, and then passes the clone to icmpv6_send().
The clone still carries the outer packet's inet6_skb_parm in skb->cb.
If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao
remains non-zero after skb_pull(). icmpv6_send() later calls
mip6_addr_swap(), which uses that stale dsthao offset against the quoted
inner packet. A malformed inner destination-options header can then make
the HAO lookup and address swap run past the end of the quoted packet
and corrupt skb_shared_info.
Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the
reply path does not reuse metadata left by the outer IPv6 stack.
Fixes: e490d1d85c ("[IPV6] IP6TUNNEL: Split out generic routine in ip6ip6_err().")
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/fe1a5e765fbca88d69391887f0ed26a19e3e4d39.1785736562.git.zhilinz@nebusec.ai
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rt6_route_rcv() validates the Route Information option (RFC 4191) length
against the prefix length, but both checks are off by one.
rinfo->length is the ND option length in units of 8 octets and it
*includes* the 8-byte option header, so an option carrying N bytes of
prefix has length == 1 + N/8. RFC 4191 section 2.3 requires length 3
when Prefix Length is greater than 64, and 2 or 3 when it is greater
than 0. The code accepts length >= 2 and length >= 1 respectively.
ipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix,
so a Router Advertisement with (prefix_len=128, length=2) or
(prefix_len=64, length=1) makes the kernel read up to 8 bytes past the
end of the option. Those bytes end up in the prefix of the route that
gets installed, so they are visible to userspace:
# RA with a Route Information option (prefix_len=128, length=2)
# followed by a source link-layer address option, 01 01 de ad be ef ca fe
$ ip -6 route show
2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra
^^^^^^^^^^^^^^^^^^ the next option, read out of bounds
When the Route Information option is the last one in the packet, those
eight bytes come from the skb tail room instead.
Reject the option lengths RFC 4191 does not allow.
Fixes: 70ceb4f539 ("[IPV6]: ROUTE: Add experimental support for Route Information Option in RA (RFC4191).")
Cc: stable@vger.kernel.org
Signed-off-by: Yuejie Shi <syjcnss@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260730035310.74584-1-syjcnss@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When adding a source-specific route creates a new subtree, fib6_add()
installs fib6_null_entry as the temporary leaf of the new subtree root
and takes a fib6_info reference for that holder.
If adding the first source leaf fails, the code frees the just allocated
subtree root but leaves that hold behind. fib6_null_entry is a per-netns
sentinel and is freed directly at netns teardown, so this does not keep
the object alive. However, it leaves its visible refcount permanently
elevated and can eventually saturate the refcount on repeated failures.
Drop the null-entry reference before freeing the unlinked subtree root.
Fixes: 5ea715289a ("ipv6: broadly use fib6_info_hold() helper")
Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Link: https://patch.msgid.link/20260727185339.1545169-1-shuangpeng.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
fib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),
but leaves res->rt6 pointing at the released rt6_info.
If no later rule supplies a replacement, fib6_rule_lookup() still sees
res.rt6 and returns that stale dst to its caller. A suppressing rule can
therefore leak a released route back to rt6_lookup(), and the next put
hits rcuref_put_slowpath() from dst_release().
Clear res->rt6 when suppressing the route so suppressed lookups fall
through to the null dst instead of reusing the released one.
Fixes: cdef485217 ("ipv6: fix memory leak in fib6_rule_suppress")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Signed-off-by: Ren Wei <enjou1224z@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/4b8acb7787d54e440155585dd32ebdf0bef7d122.1784710966.git.zhilinz@nebusec.ai
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When inet_getpeer_v4() or inet_getpeer_v6() fails to allocate a peer entry
under memory pressure or tree size caps, redirect handlers previously fell
back to sending un-rate-limited ICMP/NDISC Redirect messages.
In IPv4, ip_rt_send_redirect() called icmp_send() directly when peer == NULL.
In IPv6, ip6_forward() and ndisc_send_redirect() passed a NULL peer into
inet_peer_xrlim_allow(), which returned true when peer == NULL.
Because ICMP/NDISC Redirects are not part of the default global rate limit
mask (sysctl_icmp_ratemask), sending redirects when peer == NULL creates
an un-rate-limited ICMP packet storm.
Fix this by failing closed in ip_rt_send_redirect(), ip6_forward(), and
ndisc_send_redirect() when peer is NULL.
Fixes: 92d8682926 ("inetpeer: Move ICMP rate limiting state into inet_peer entries.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260724072901.1633601-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since the call to __ip6_del_rt_siblings has been converted under
rcu read lock and it only has one call point
we should no longer block or yield.
Our stack trace from the syzbot reproducer looks as follows:
__ip6_del_rt_siblings
rtnl_notify (Here we pass gfp_any() -> GFP_KERNEL)
nlmsg_notify
nlmsg_multicast
nlmsg_multicast_filtered
netlink_broadcast_filtered (GFP_KERNEL passed from earlier)
netlink_broadcast_filtered can yield if GFP_KERNEL
is passed, which we do not want to happen.
Fix this by changing the allocation flag of rtnl_notify.
Also change the flag passed to nlmsg_new. Even though it
is not related to the syzbot generated bug it still falls
under the same requirements.
Reported-by: syzbot+84d4a405ed798b40c96d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=84d4a405ed798b40c96d
Fixes: bd11ff421d ("ipv6: Get rid of RTNL for SIOCDELRT and RTM_DELROUTE.")
Signed-off-by: Nikola Z. Ivanov <zlatistiv@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260719105759.558050-1-zlatistiv@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In raw6_icmp_error(), raw_v6_match() is called with inet6_iif(skb) passed
to both the 'dif' and 'sdif' arguments. This is a copy-paste or typo error,
as the last argument should represent the secondary interface index (sdif).
This mismatch breaks ICMPv6 error handling for IPv6 raw sockets in VRF
(Virtual Routing and Forwarding) environments. When a raw socket is bound
to a VRF master device, raw_v6_match() fails to find a match because it is
not given the correct sdif value, causing the socket to miss relevant
ICMPv6 error notifications.
Fix this by properly passing inet6_sdif(skb) as the last argument to
raw_v6_match().
Fixes: 5108ab4bf4 ("net: ipv6: add second dif to raw socket lookups")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260717143230.1836-1-lirongqing@baidu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Before commit 00d066a4d4 ("netdev_features: convert NETIF_F_LLTX to
dev->lltx"), NETIF_F_LLTX was set unconditionally in both
__gre_tunnel_init() and ip6gre_tnl_init_features() alongside
GRE_FEATURES:
dev->features |= GRE_FEATURES | NETIF_F_LLTX;
When that commit converted NETIF_F_LLTX to the dev->lltx flag, it
placed 'dev->lltx = true' after the SEQ/CSUM early returns instead
of before them. This causes GRE/GRETAP/ip6gre tunnels with SEQ or
CSUM+encap to lose lockless TX, reintroducing _xmit_lock acquisition
around their ndo_start_xmit. Since GRE xmit re-enters the stack via
ip_tunnel_xmit(), holding _xmit_lock risks ABBA deadlock with the
underlay device.
CPU0 CPU1
---- ----
lock(&qdisc_xmit_lock_key#6);
lock(&qdisc_xmit_lock_key#3);
lock(&qdisc_xmit_lock_key#6);
lock(&qdisc_xmit_lock_key#3);
Fix by moving dev->lltx = true before the early returns in both
functions, restoring the original unconditional behavior.
Fixes: 00d066a4d4 ("netdev_features: convert NETIF_F_LLTX to dev->lltx")
Signed-off-by: Yun Zhou <yun.zhou@windriver.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260713150945.1779628-1-yun.zhou@windriver.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
ila_csum_adjust_transport() caches ip6h = ipv6_hdr(skb) before calling
pskb_may_pull(). On a non-linear skb whose transport header sits in a page
fragment, pskb_may_pull() can call __pskb_pull_tail() / pskb_expand_head()
and free the old skb head, leaving ip6h dangling; the following
get_csum_diff(ip6h, p) then reads freed memory. ila_update_ipv6_locator()
uses ip6h (and the iaddr derived from it) again after the csum-adjust
call and additionally writes the new locator through that pointer.
Impact: a remote IPv6 packet routed through a configured ILA
csum-adjust-transport route or receive-side mapping triggers a
slab-use-after-free in ila_update_ipv6_locator() (KASAN). The route or
mapping requires CAP_NET_ADMIN to configure, but trigger packets are
unauthenticated once it exists.
Reload ip6h after each pskb_may_pull() in ila_csum_adjust_transport()
before the csum-diff read. In ila_update_ipv6_locator() only the
ILA_CSUM_ADJUST_TRANSPORT case pulls the skb, so reload ip6h and iaddr in
that case alone before the destination-address write; the neutral-map
modes never pull and keep their cached pointers.
Fixes: 33f11d1614 ("ila: Create net/ipv6/ila directory")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Link: https://patch.msgid.link/20260714114903.3763420-1-michael.bommarito@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tcp_v4_send_ack() and tcp_v6_send_response() construct standalone TCP
responses with TCP-AO options. The option length carries the actual MAC
length, but the TCP header length includes the option rounded up to a
four-byte boundary.
tcp_ao_hash_hdr() writes the MAC only. Thus, when the MAC length is not
four-byte aligned, the one to three bytes after the MAC are left
uninitialized and may be transmitted. For the normal TCP-AO hashing
mode, those bytes also have to be initialized before computing the MAC.
Initialize only the alignment padding in the TCP-AO branches, before
hashing the header. Use TCPOPT_NOP, as in the normal TCP-AO output path.
This avoids adding work to non-AO TCP responses while preserving a valid
authenticated header.
Fixes: decde2586b ("net/tcp: Add TCP-AO sign to twsk")
Fixes: da7dfaa6d6 ("net/tcp: Consistently align TCP-AO option in the header")
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>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260713105631.8616-1-zhaoyz24@mails.tsinghua.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Florian Westphal says:
====================
netfilter: updates for net
The following patchset contains Netfilter fixes for *net*.
These are fixes for bugs except patches 6 and 9 which fix issues added in
last PR and 7.1-rc1.
1) Reject unsupported target families in xt_nat_checkentry().
From Wyatt Feng.
2) Fix inverted time_after() check in ecache_work_evict_list().
Causes pointless work rescheds and thus way longer time to
clear the pending event backlog. From Yizhou Zhao.
3) Fix a use-after-free in br_ip6_fragment() caused by a dangling prevhdr
pointer. From Xiang Mei.
4) Fix incorrect conntrack zone comparison in nf_conncount tuple
deduplication. Pass IP_CT_DIR_ORIGINAL, not zone direction.
From Yizhou Zhao.
5) Add bridge tunnel flowtable regression test for a bug that
got fixed in the previous PR. From Zhengyang Chen.
6) Use the correct direction when setting up tunnel routes in the flowtable
xmit path. From Pablo Neira Ayuso. This fixes a bug added in the
previous PR.
7) Reload IP header after potential skb head reallocation in IPVS.
8) Fix incorrect IPv6 transport offsets in TCP application code. Correct the
ICMPv6 header offset to ensure proper checksumming with extension headers,
from Julian Anastasov. this is a followup to the previous PR.
9) Remove null-termination requirement for xt_physdev masks, this broke
device names with 15 characters.
netfilter pull request nf-26-07-10
* tag 'nf-26-07-10' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: xt_physdev: masks are not c-strings
ipvs: fix more places with wrong ipv6 transport offsets
ipvs: reload ip header after head reallocation
netfilter: flowtable: use correct direction to set up tunnel route
selftests: netfilter: add bridge tunnel flowtable regression
netfilter: nf_conncount: fix zone comparison in tuple dedup
netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()
netfilter: ecache: fix inverted time_after() check
netfilter: xt_nat: reject unsupported target families
====================
Link: https://patch.msgid.link/20260710143733.29741-1-fw@strlen.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Steffen Klassert says:
====================
pull request (net): ipsec 2026-07-10
1) xfrm: propagate -EINPROGRESS from validate_xmit_xfrm()
Return -EINPROGRESS from xfrm_output_one when validate_xmit_xfrm
requeues the packet asynchronously, so the caller doesn't treat it
as a real error and free the skb.
2) xfrm: fix stale skb->prev after async crypto steals a GSO segment
Re-derive skb->prev from the fragment list after async crypto splits
a GSO skb, keeping the linked-list pointers validi.
3) xfrm: nat_keepalive: avoid double free on send error
Hold a state ref while the nat_keepalive timer is active and drop the
timer before freeing the state, preventing a re-entered free on send
error.
4) xfrm: fix sk_dst_cache double-free in xfrm_user_policy()
Null the skb dst cache before freeing the policy so a later skb
destructor doesn't double-free it.
5) xfrm: cache the offload ifindex for netlink dumps
Cache the device ifindex at state-add time and use it for netlink
dumps instead of dereferencing dst->dev, which may have changed by
the time the dump runs.
6) xfrm: reject optional IPTFS templates in outbound policies
Reject outbound policies with an optional IPTFS template,
IPTFS must always be used if configured.
7) xfrm: clear mode callbacks after failed mode setup
Clear the mode->init_flags and init_state callbacks on the error path
after xfrm_init_mode fails, so a partially-initialised mode isn't
reused in xfrm_state_construct.
8) xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()
Propagate SKBFL_SHARED_FRAG from the original skb to fragments
allocated by iptfs_skb_add_frags, keeping shared-fragment accounting
correct after IPTFS reassembly.
9) xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()
Clear dst->dev on the error path of xfrm6_fill_dst() so the caller
doesn't release the netdev reference twice via dst_release.
10) xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert
Preallocate all inexact hash bins before existing entries are
reinserted during xfrm_hash_rebuild, so reinsertion always hits an
existing bin.
Please pull or let me know if there are problems.
ipsec-2026-07-10
* tag 'ipsec-2026-07-10' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert
xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()
xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()
xfrm: clear mode callbacks after failed mode setup
xfrm: reject optional IPTFS templates in outbound policies
xfrm: cache the offload ifindex for netlink dumps
xfrm: fix sk_dst_cache double-free in xfrm_user_policy()
xfrm: nat_keepalive: avoid double free on send error
xfrm: fix stale skb->prev after async crypto steals a GSO segment
xfrm: propagate -EINPROGRESS from validate_xmit_xfrm()
====================
Link: https://patch.msgid.link/20260710090349.343389-1-steffen.klassert@secunet.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
br_ip6_fragment() gets prevhdr, a pointer into the skb head, from
ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb
skb_checksum_help() reallocates the head via pskb_expand_head(), leaving
prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a
use-after-free write.
Save prevhdr's offset before skb_checksum_help() and recompute it after,
like commit ef0efcd3bd ("ipv6: Fix dangling pointer when ipv6
fragment").
BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)
Write of size 1 at addr ffff888013ff5016 by task exploit/141
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip6_frag_next (net/ipv6/ip6_output.c:857)
br_ip6_fragment (net/ipv6/netfilter.c:212)
nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)
nf_hook_slow (net/netfilter/core.c:619)
br_forward_finish (net/bridge/br_forward.c:66)
__br_forward (net/bridge/br_forward.c:115)
maybe_deliver (net/bridge/br_forward.c:191)
br_flood (net/bridge/br_forward.c:245)
br_handle_frame_finish (net/bridge/br_input.c:229)
br_handle_frame (net/bridge/br_input.c:442)
...
packet_sendmsg (net/packet/af_packet.c:3114)
...
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Kernel panic - not syncing: Fatal exception in interrupt
Fixes: 764dd163ac ("netfilter: nf_conntrack_bridge: add support for IPv6")
Cc: stable@vger.kernel.org
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Signed-off-by: Florian Westphal <fw@strlen.de>
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>
nf_ct_frag6_reasm() slides the packet head forward to drop the IPv6
fragment header and then unconditionally advances skb->mac_header:
skb->mac_header += sizeof(struct frag_hdr);
On the NF_INET_LOCAL_OUT defrag path the skb has no link-layer header
yet, so skb->mac_header is still the "not set" sentinel (u16)~0U. Adding
sizeof(struct frag_hdr) wraps it to a small value (0xffff + 8 == 7),
after which skb_mac_header_was_set() wrongly reports a MAC header is
present and skb_mac_header() points into the headroom.
The reassembler has done this unconditional add since it was introduced;
it was harmless while mac_header was a bare pointer, but wrong once
mac_header became a u16 offset whose unset state is the ~0U sentinel
tested by skb_mac_header_was_set(). The sibling net/ipv6/reassembly.c
does the same relocation and does guard the adjustment; mirror the
guard here.
Fixes: 9fb9cbb108 ("[NETFILTER]: Add nf_conntrack subsystem.")
Cc: stable@vger.kernel.org
Reported-by: Weiming Shi <bestswngs@gmail.com>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Florian Westphal <fw@strlen.de>
A race condition exists between device teardown and incoming MLD query
processing, leading to a Use-After-Free in the MLD delayed work.
During device destruction, the primary reference to inet6_dev is dropped,
which can drop its refcount to 0. The actual freeing of inet6_dev memory
is deferred via RCU.
Concurrently, the packet receive path runs under RCU read lock and obtains
the inet6_dev pointer. Because the memory is RCU-protected, CPU-0 can
safely dereference inet6_dev even if its refcount has hit 0.
However, if CPU-0 calls igmp6_event_query() and schedules delayed work, it
attempts to acquire a reference using in6_dev_hold(). This increments the
refcount from 0 to 1, triggering a "refcount_t: addition on 0" warning.
Since the inet6_dev memory is still scheduled to be freed after the RCU
grace period, the device is freed while the work is still scheduled.
When the work runs, it accesses the freed memory, causing a kernel panic.
Fix this by using refcount_inc_not_zero() (via a new helper
in6_dev_hold_safe()) to prevent acquiring a reference if the device is
already being destroyed. If the refcount is 0, we do not schedule the work.
Fixes: 1da177e4c3 ("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/20260705181756.963063-3-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
On the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst()
releases the device reference with netdev_put() but leaves
xdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev)
again, so the same net_device reference is released twice, underflowing
its refcount (ref_tracker WARNING + "unregister_netdevice: waiting for
<dev> to become free").
Clear xdst->u.dst.dev after the netdev_put(), the same way the XFRM
device-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in
net/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error.
ref_tracker: reference already released.
ref_tracker: allocated in:
xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86)
...
udpv6_sendmsg (net/ipv6/udp.c:1696)
...
ref_tracker: freed in:
xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90)
...
WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780
dst_destroy (net/core/dst.c:115)
rcu_core
handle_softirqs
...
Fixes: 84c4a9dfbf ("xfrm6: release dev before returning error")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The ah, hbh and rt matches check that the fixed extension header is
present, then use the header length field to derive the advertised
extension header length for matching.
For the ah match, add the missing advertised-length check. For hbh
and rt, update the existing advertised-length checks. In all three
cases, set hotdrop to true before returning false when the advertised
extension header length exceeds the available skb data.
Returning false treats the packet as a rule mismatch. Set hotdrop to
true and drop malformed packets so they cannot bypass rules intended
to drop packets with these IPv6 extension headers.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Zhixing Chen <running910@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
inet6_dump_fib() saves its progress in cb->args[1] as a positional
index within the current hash chain. Between batches, a concurrent
fib6_new_table() can insert a new table at the chain head, shifting
all existing entries. The saved index then lands on a different
table, causing fib6_dump_table() to set w->root to the wrong table
while w->node still points into the previous one.
fib6_walk_continue() dereferences w->node->parent (NULL) and panics:
BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:fib6_walk_continue+0x6e/0x170
Call Trace:
<TASK>
fib6_dump_table.isra.0+0xc5/0x240
inet6_dump_fib+0xf6/0x420
rtnl_dumpit+0x30/0xa0
netlink_dump+0x15b/0x460
netlink_recvmsg+0x1d6/0x2a0
____sys_recvmsg+0x17a/0x190
Fix by storing tb->tb6_id in cb->args[1] instead of a positional
index. On resume, skip entries until the id matches; a concurrent
head-insert can never match the saved id, so the walker always
resumes on the correct table.
Fixes: 1b43af5480 ("[IPV6]: Increase number of possible routing tables to 2^32")
Signed-off-by: Pengfei Zhang <zhangfeionline@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260625070517.965597-1-zhangfeionline@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
seg6_validate_srh() reads fixed SRH fields such as srh->type and
srh->hdrlen before checking that the supplied length covers the fixed
struct ipv6_sr_hdr fields.
The BPF SEG6 encap path reaches this with a BPF program-supplied pointer
and length: bpf_lwt_push_encap() and the SEG6 local BPF END_B6 and
END_B6_ENCAP actions call bpf_push_seg6_encap(), which forwards the
length to seg6_validate_srh() with no minimum-size guard. A 2-byte SEG6
encap header can therefore make the validator read srh->type at offset 2
beyond the caller-supplied buffer.
Reject lengths shorter than the fixed SRH at the top of
seg6_validate_srh(), before any field is read. This fixes the BPF helper
path and keeps the common validator robust.
Fixes: fe94cc290f ("bpf: Add IPv6 Segment Routing helpers")
Signed-off-by: Nuoqi Gui <gnq25@mails.tsinghua.edu.cn>
Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Link: https://patch.msgid.link/20260623-f01-17-seg6-srh-len-v2-1-2edc40e9e3e1@mails.tsinghua.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When changing the ignore_routes_with_linkdown sysctl for a specific
interface, the RTM_NEWNETCONF netlink notification was not being emitted
to userspace. Fix this by emitting the notification when needed.
In addition, fix bogus return value for successful "all" and specific
interface write operation leading to a wrong reset of the position
pointer.
Fixes: 35103d1117 ("net: ipv6 sysctl option to ignore routes when nexthop link is down")
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260622130857.5115-7-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When handling proxy_ndp, if rtnl_net_trylock() fails, the operation is
retried but as the value was already modified by the initial
proc_dointvec() call, the restarted syscall will read the newly modified
value as the 'old' state.
Fix this by taking the RTNL lock before parsing the input value if the
operation is a write.
Fixes: c92d5491a6 ("netconf: add support for IPv6 proxy_ndp")
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260622130857.5115-6-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When writing to the disable_policy sysctl, if proc_dointvec() fails to
parse the input, it returns a negative error code. The current
implementation is resetting the position argument even if an error
occurred during proc_dointvec() and not only during sysctl restart.
Fix this by checking the return value of proc_dointvec() and returning
early on failure.
Fixes: df789fe752 ("ipv6: Provide ipv6 version of "disable_policy" sysctl")
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260622130857.5115-5-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When writing to the forwarding sysctl, if proc_dointvec() fails to parse
the input, it returns a negative error code. The current implementation
is overwriting that error for write operations.
This results in a silent failure, it returns a successful write although
the configuration was not modified at all. When modifying the "all"
variant it can also modify the configuration of existing interfaces to
the wrong value.
Fix this by checking the return value of proc_dointvec() and returning
early on failure. In addition, adjust return code of
addrconf_fixup_forwarding() for successful operation.
Fixes: b325fddb7f ("ipv6: Fix sysctl unregistration deadlock")
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260622130857.5115-4-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When writing to the ignore_routes_with_linkdown sysctl, if
proc_dointvec() fails to parse the input, it returns a negative error
code. The current implementation is overwriting that error for write
operations.
This results in a silent failure, it returns a successful write although
the configuration was not modified at all. When modifying the "all"
variant it can also modify the configuration of existing interfaces to
the wrong value.
Fix this by checking the return value of proc_dointvec() and returning
early on failure.
Fixes: 35103d1117 ("net: ipv6 sysctl option to ignore routes when nexthop link is down")
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260622130857.5115-3-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When writing to the disable_ipv6 sysctl, if proc_dointvec() fails to
parse the input, it returns a negative error code. The current
implementation is overwriting that error for write operations.
This results in a silent failure, it returns a successful write although
the configuration was not modified at all. When modifying the "all"
variant it can also modify the configuration of existing interfaces to
the wrong value.
Fix this by checking the return value of proc_dointvec() and returning
early on failure.
Fixes: 56d417b12e ("IPv6: Add 'autoconf' and 'disable_ipv6' module parameters")
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260622130857.5115-2-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Steffen Klassert says:
====================
pull request (net): ipsec 2026-06-22
1) xfrm: use compat translator only for u64 alignment mismatch
Gate the XFRM_USER_COMPAT translator on COMPAT_FOR_U64_ALIGNMENT
so 32-bit compat tasks on arches whose 32-bit ABI already matches
the native 64-bit layout are no longer rejected with -EOPNOTSUPP.
From Sanman Pradhan.
2) net: af_key: initialize alg_key_len for IPComp states
Initialize the alg_key_len to 0 in the IPComp branch of
pfkey_msg2xfrm_state() so an uninitialized value cannot drive
xfrm_alg_len() into a slab-out-of-bounds kmemdup during
XFRM_MSG_MIGRATE. From Zijing Yin.
3) xfrm: Fix dev use-after-free in xfrm async resumption
Stash the original skb->dev and extend the RCU critical section
across xfrm_rcv_cb() and transport_finish() to prevent a
tunnel-device UAF and original-device refcount leak when a
callback replaces skb->dev. From Dong Chenchen.
4) xfrm: Fix xfrm state cache insertion race
Move the state-validity check inside xfrm_state_lock in the
input state cache insertion path so a state cannot be killed
between the check and the insert. From Herbert Xu.
5) xfrm: annotate data-races around xfrm_policy_count[] and xfrm_policy_default[]
Add READ_ONCE()/WRITE_ONCE() annotations on xfrm_policy_count
and xfrm_policy_default to silence the KCSAN data race reported
on net->xfrm.policy_count. From Eric Dumazet.
6) espintcp: use sk_msg_free_partial to fix partial send
Replace the manual skmsg accounting in espintcp with
sk_msg_free_partial() so the skmsg stays consistent on every
iteration and the partial-send accounting bugs go away.
From Sabrina Dubroca.
7) xfrm: validate selector family and prefixlen during match
Reject mismatched address families in xfrm_selector_match() and
bound prefixlen in addr4_match()/addr_match() to prevent the
shift-out-of-bounds syzbot reported when an AF_UNSPEC selector
with a large prefixlen is matched against an IPv4 flow.
From Eric Dumazet.
* tag 'ipsec-2026-06-22' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: validate selector family and prefixlen during match
espintcp: use sk_msg_free_partial to fix partial send
xfrm: annotate data-races around xfrm_policy_count[] and xfrm_policy_default[]
xfrm: Fix xfrm state cache insertion race
xfrm: Fix dev use-after-free in xfrm async resumption
net: af_key: initialize alg_key_len for IPComp states
xfrm: use compat translator only for u64 alignment mismatch
====================
Link: https://patch.msgid.link/20260622075726.29685-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
fib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and
dereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown()
clears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has
released tb6_lock, so the RA-driven MTU walk can observe a NULL idev and
oops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(),
but this re-fetch is unguarded; nexthop-backed routes survive
addrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is
nulled.
Return 0 when idev is NULL, matching rt6_mtu_change_route() and the
fib6_mtu() fix in commit 5ad509c1fd ("ipv6: Fix null-ptr-deref in
fib6_mtu().").
Oops: general protection fault, ... KASAN: null-ptr-deref in range
[0x00000000000002a8-0x00000000000002af]
RIP: 0010:fib6_nh_mtu_change+0x203/0x990
rt6_mtu_change_route+0x141/0x1d0
__fib6_clean_all+0xd0/0x160
rt6_mtu_change+0xb4/0x100
ndisc_router_discovery+0x24b5/0x2cb0
icmpv6_rcv+0x12e9/0x1710
ipv6_rcv+0x39b/0x410
Fixes: c0b220cf7d ("ipv6: Refactor exception functions")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260619045334.2427073-1-xmei5@asu.edu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for net. This batches
fixes for real crashes with trivial/correctness fixes. There is too
a rework of the conntrack expectation timeout strategy to deal with
a possible race when removing an expectation.
1) Fix the incorrect flowtable timeout extension for entries in
hw offload, from Adrian Bente. This is correcting a defect in
the functionality, no crash.
2) Hold reference to device under the fake dst in br_netfilter,
from Haoze Xie. This is fixing a possible UaF if the device
is removed while packet is sitting in nfqueue.
3) Reject template conntrack in xt_cluster, otherwise access to
uninitialize conntrack fields are possible leading to WARN_ON
due to unset layer 3 protocol. From Wyatt Feng.
4) Make sure the IPv6 tunnel header is in the linear skb data
area before pulling. While at it remove incomplete NEXTHDR_DEST
support. From Lorenzo Bianconi. This possibly leading to crash
if IPv4 header is not in the linear area.
5) Use test_bit_acquire in ipset hash set to avoid reordering
of subsequent memory access. This is addressing a LLM related
report, no crash has been observed. From Jozsef Kadlecsik.
6) Use test_bit_acquire in ipset bitmap set too, for the same
reason as in the previous patch, from Jozsef Kadlecsik.
7) Call kfree_rcu() after rcu_assign_pointer() to address a
possible UaF if kfree_rcu() runs inmediately, which to my
understanding never happens. Never observed in practise,
reported by LLM. Also from Jozsef Kadlecsik.
8) Use disable_delayed_work_sync() instead cancel_delayed_work_sync()
to avoid that ipset GC handler re-queues work as reported by LLM.
From Jozsef Kadlecsik. This is for correctness.
9) Restore the check in nft_payload for exceeding payloda offset
over 2^16. From Florian Westphal. This fixes a silent truncation,
not a big deal, but better be assertive and reject it.
10) Validate NFT_META_BRI_IIFHWADDR can only run from bridge
prerouting. From Florian Westphal. Harmless but it could allow
to read bytes from skb->cb.
11) Zero out destination hardware address during the flowtable
path setup, also from Florian. This is a correctness fix, LLM
points that possible infoleak can happen but topology to achieve
it is not clear.
12) Skip IPv4 options if present when building the IPV4 reject reply.
Otherwise bytes in the IPv4 options header can be sent back to
origin where the ICMP header is being expected. Again from
Florian Westphal.
13) Replace timer API for expectation by GC worker approach. This
is implicitly fixing a race between nf_ct_remove_expectations()
which might fail to remove the expectation due to timer_del()
returning false because timer has expired and callback is
being run concurrently. This fix is addressing a crash that has
been already reported with a reproducer.
14) Check if br_vlan_get_pvid_rcu() fails, otherwise possible stack
infoleak of 4-bytes. From Florian Westphal.
* tag 'nf-26-06-21' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nft_meta_bridge: fix NFT_META_BRI_IIFPVID stack leak
netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
netfilter: nf_reject: skip iphdr options when looking for icmp header
netfilter: nft_flow_offload: zero device address for non-ether case
netfilter: nft_meta_bridge: add validate callback for get operations
netfilter: nft_payload: reject offsets exceeding 65535 bytes
netfilter: ipset: make sure gc is properly stopped
netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()
netfilter: ipset: Don't use test_bit() in lockless RCU readers in bitmap types
netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types
netfilter: flowtable: fix and simplify IP6IP6 tunnel handling
netfilter: xt_cluster: reject template conntracks in hash match
netfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst
netfilter: flowtable: fix offloaded ct timeout never being extended
====================
Link: https://patch.msgid.link/20260620222738.112506-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IOAM uses a dummy dst_entry(null_dst) to mark that the destination should
not be changed after the transformation. This dst is stored in the IOAM lwt
state and may be passed to dst_cache_set_ip6().
However, the IPv6 dst cache path eventually calls rt6_get_cookie(), which
treats the dst_entry as part of a struct rt6_info. Since the null_dst was
embedded directly as a struct dst_entry in struct ioam6_lwt, this resulted
in an invalid cast and rt6_get_cookie() reading fields from the wrong
object.
In practice, the wrong cookie is not used while dst->obsolete is zero, but
rt6_get_cookie() may also access per-cpu value when rt->sernum is
zero. In this case, rt->sernum aliases ioam6_lwt::cache::reset_ts, which
can become zero, making this a potential invalid pointer access.
Fix this by embedding a full struct rt6_info for the dummy IPv6 route and
passing its dst member to the dst APIs.
Fixes: 47ce7c8545 ("net: ipv6: ioam6: fix double reallocation")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Link: https://patch.msgid.link/20260618104336.48934-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In __ip6_append_data(), when the paged-allocation branch is taken
(MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are
computed as
alloclen = fragheaderlen + transhdrlen;
pagedlen = datalen - transhdrlen;
datalen already includes fraggap (datalen = length + fraggap). When
fraggap is non-zero, this is not the first skb and transhdrlen is zero.
The fraggap bytes carried over from the previous skb are copied just past
the fragment headers in the new skb's linear area. The linear area is
therefore undersized by fraggap bytes while pagedlen is overstated by the
same amount, and the copy writes past skb->end into the trailing
skb_shared_info.
An unprivileged user can trigger this via a UDPv6 socket using
MSG_MORE together with MSG_SPLICE_PAGES.
The bad accounting was introduced by commit 773ba4fe91 ("ipv6:
avoid partial copy for zc"). Before commit ce650a1663 ("udp6: Fix
__ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative
copy value caused -EINVAL to be returned. That later commit allowed
MSG_SPLICE_PAGES to proceed in this case, making the corruption
triggerable.
The non-paged branch sets alloclen to fraglen, which already accounts
for fraggap because datalen does. Bring the paged branch in line by
adding fraggap to alloclen and subtracting it from pagedlen.
After this adjustment, copy no longer collapses to -fraggap on the
paged path, so remove the stale comment describing that old arithmetic.
Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES
case, remove the MSG_SPLICE_PAGES exception from the negative copy check.
Fixes: 773ba4fe91 ("ipv6: avoid partial copy for zc")
Signed-off-by: Jungwoo Lee <jwlee2217@gmail.com>
Signed-off-by: Wongi Lee <qw3rtyp0@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/ajFTqRljatR17fFy@DESKTOP-19IMU7U.localdomain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
accept_untracked_na() re-fetches the inet6_dev with __in6_dev_get(dev)
and dereferences idev->cnf.accept_untracked_na without a NULL check,
even though its only caller ndisc_recv_na() already fetched and
NULL-checked idev for the same device.
Both reads of dev->ip6_ptr run in the same RCU read-side critical
section, but a concurrent addrconf_ifdown() can clear dev->ip6_ptr
between them: lowering the MTU below IPV6_MIN_MTU calls addrconf_ifdown()
without the synchronize_net() that orders the unregister path, so the
re-fetch returns NULL and oopses:
BUG: KASAN: null-ptr-deref in ndisc_recv_na (net/ipv6/ndisc.c:974)
Read of size 4 at addr 0000000000000364
Call Trace:
<IRQ>
ndisc_recv_na (net/ipv6/ndisc.c:974)
icmpv6_rcv (net/ipv6/icmp.c:1193)
ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479)
ip6_input_finish (net/ipv6/ip6_input.c:534)
ip6_input (net/ipv6/ip6_input.c:545)
ip6_mc_input (net/ipv6/ip6_input.c:635)
ipv6_rcv (net/ipv6/ip6_input.c:351)
</IRQ>
It is reachable by an unprivileged user via a network namespace.
Pass the caller's already validated idev instead of re-fetching it; the
idev stays alive for the whole RCU critical section, so it is safe even
after dev->ip6_ptr has been cleared.
Fixes: aaa5f515b1 ("net: ipv6: new accept_untracked_na option to accept na only if in-network")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://patch.msgid.link/20260617065512.2529757-2-bestswngs@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Fix nf_flow_ip6_tunnel_proto() to use pskb_may_pull() instead of
skb_header_pointer() to ensure the outer IPv6 header is in the skb
headroom, which is required for subsequent packet processing. Move
ctx->offset update inside the IPPROTO_IPV6 conditional block since it
should only be adjusted when an IP6IP6 tunnel is actually detected.
Simplify the rx path by removing ipv6_skip_exthdr() and checking
ip6h->nexthdr directly, as the flowtable fast path only handles simple
IP6IP6 encapsulation without extension headers.
Drop the tunnel encapsulation limit destination option support from the
tx path to match, since the rx path no longer handles extension headers.
Remove the encap_limit parameter from nf_flow_offload_ipv6_forward(),
nf_flow_tunnel_ip6ip6_push() and nf_flow_tunnel_v6_push(), along with
the ipv6_tel_txoption struct and related headroom/MTU adjustments.
Fixes: d98103575d ("netfilter: flowtable: Add IP6IP6 rx sw acceleration")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Merge in late fixes in preparation for the net-next PR.
Conflicts:
net/tls/tls_sw.c
406e8a651a ("net: skmsg: preserve sg.copy across SG transforms")
79511603a6 ("tls: remove dead sockmap (psock) handling from the SW path")
drivers/net/ethernet/microsoft/mana/mana_en.c
f8fd56977e ("net: mana: guard TX wq object destroy with INVALID_MANA_HANDLE check")
d07efe5a6e ("net: mana: Use per-queue allocation for tx_qp to reduce allocation size")
https://lore.kernel.org/ajAPXu-C_PuTgV-a@sirena.org.uk
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently sk_rethink_txhash() re-rolls the socket's txhash on RTO, PLB,
and spurious-retransmission events, but the cached route is reused and
the new hash is not propagated into the ECMP path selection logic. Two
changes are needed to make rehash select a different local ECMP path:
1. Add __sk_dst_reset() alongside sk_rethink_txhash() in
tcp_write_timeout(), tcp_rcv_spurious_retrans(), and
tcp_plb_check_rehash() so the cached dst is invalidated and the
next transmit triggers a fresh route lookup.
2. Set fl6->mp_hash from sk_txhash (or tcp_rsk(req)->txhash for
SYN/ACK retransmits and syncookies) in tcp_v6_connect(),
inet6_sk_rebuild_header(), inet6_csk_route_req(),
inet6_csk_route_socket(), tcp_v6_send_response(), and
cookie_v6_check() so fib6_select_path() picks a path based on the
new hash.
The mp_hash override only applies to fib_multipath_hash_policy 0 (the
default L3 policy). Its hash includes the flow label, but that is 0 by
default -- np->flow_label is unset, and auto_flowlabels only computes
the on-wire label later, per packet -- so flows to the same peer share
one local path. Keying the hash on sk_txhash makes the local path
per-connection and lets a rehash re-select it. Policies 1-3 are left
unchanged.
The mp_hash assignment is factored into a small helper,
ip6_ecmp_set_mp_hash(), shared by inet6_csk_route_req(),
inet6_csk_route_socket(), tcp_v6_connect(), inet6_sk_rebuild_header(),
tcp_v6_send_response(), and cookie_v6_check(). It applies
(txhash >> 1) ?: 1 for policy 0 (the >> 1 keeps mp_hash in the 31-bit
range; ?: 1 keeps it non-zero, since 0 would fall back to
rt6_multipath_hash()). inet6_csk_route_socket() calls it only for
sk_protocol == IPPROTO_TCP so that non-TCP callers (e.g., L2TP via
inet6_csk_xmit) fall through to rt6_multipath_hash() and retain their
existing flow-key-based ECMP behavior.
tcp_v6_send_response() also sets mp_hash from the response txhash so
that a control packet (a RST from the full socket, or an ACK from a
time-wait socket) selects the same local ECMP nexthop as the
connection's txhash rather than falling back to the flow hash. The
time-wait socket's tw_txhash is copied from sk_txhash when the
connection enters TIME_WAIT, so it reflects any rehash that occurred.
Setting mp_hash explicitly is necessary because the default ECMP hash
derives from fl6->flowlabel via np->flow_label, which is not updated
from sk_txhash (REPFLOW is off by default). ip6_make_flowlabel()
cannot help either, as it runs after the route lookup.
As a consequence, for policy 0 the local ECMP path of an IPv6 TCP
flow follows sk_txhash even when fl6->flowlabel is non-zero, e.g. a
reflected (REPFLOW) or explicitly set (IPV6_FLOWLABEL_MGR) flow
label. This is intentional: only local path selection changes, so
rehash can recover from a failed path; the on-wire flow label is
unchanged.
sk_set_txhash() is moved before ip6_dst_lookup_flow() in
tcp_v6_connect() so the initial ECMP path is selected by the same
txhash that subsequent route rebuilds will use. This avoids
unintended path changes when the cached dst is naturally invalidated
(e.g., by PMTU discovery or route changes).
The rehash sites (tcp_write_timeout(), tcp_plb_check_rehash(), and
tcp_rcv_spurious_retrans()) call __sk_rethink_txhash_reset_dst(),
which re-rolls the txhash and, when it changed, drops the cached dst
so the next transmit re-runs route selection. The dst reset is
guarded by sk->sk_family == AF_INET6 since IPv4 ECMP does not
currently use sk_txhash for path selection. For IPv4-mapped IPv6
sockets this produces a redundant dst reset on a cold path
(RTO/PLB); the subsequent IPv4 route lookup returns the same result.
The helper is deliberately separate from sk_rethink_txhash() itself:
dst_negative_advice() calls sk_rethink_txhash() before its own dst op,
so resetting the dst inside sk_rethink_txhash() would skip that op
(e.g. rt6_remove_exception_rt()).
For syncookies, cookie_init_sequence() computes the cookie value
before route_req() and sets txhash so the SYN-ACK selects the same
ECMP path that cookie_v6_check() will use when the full socket is
created. cookie_tcp_reqsk_init() derives txhash from the cookie so
the full socket's ECMP path matches the SYN-ACK. Both the SYN-ACK
assignment in tcp_conn_request() and the full-socket assignment in
cookie_tcp_reqsk_init() set txhash from the cookie for IPv4 and IPv6
alike. On IPv6 this drives ECMP path selection; on IPv4, which does
not use sk_txhash for ECMP, it only affects TX-queue selection. That
selection scales the hash by its high bits (reciprocal_scale()), which
are uniform in the keyed secure_tcp_syn_cookie() output -- the MSS index
only perturbs the low bits -- so the queue distribution matches
net_tx_rndhash().
cookie_init_sequence() is split from the former version that also
called tcp_synq_overflow() and incremented SYNCOOKIESSENT; those
side effects are now in cookie_record_sent(), called after
route_req() succeeds so they are not bumped when route_req() fails.
cookie_record_sent() is guarded by CONFIG_SYN_COOKIES to
match the guard on tcp_synq_overflow(). route_req() receives 0 as
tw_isn for the syncookie path so that tcp_v6_init_req() still saves
ireq->pktopts for REPFLOW flowlabel reflection and IPv6 cmsg
options. The ecn_ok clear for syncookies without timestamps stays
after tcp_ecn_create_request() so it takes precedence.
Signed-off-by: Neil Spring <ntspring@meta.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260615042158.1600746-2-ntspring@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535).
This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535.
However, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel.
If a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will
be mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer
dereference because local TCP packets do not use frag_list.
Fix this by returning min(IPV6_MAXPLEN, GSO_BY_FRAGS - 1) (65534) from
ip6_default_advmss() when MTU is large.
Also update the stale comment in ip6_default_advmss() which suggested
that IPV6_MAXPLEN is returned to mean "any MSS".
Fixes: 3953c46c3a ("sk_buff: allow segmenting based on frag sizes")
Reported-by: syzbot+ebdb22d461c904fc3cb2@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a2c3193.8812e0fc.3c3fa4.0001.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260612162517.83394-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Steffen Klassert says:
====================
pull request (net-next): ipsec-next 2026-06-12
1) Replace the open-coded manual cleanup in xfrm_add_policy() error
path with xfrm_policy_destroy() for consistency with
xfrm_policy_construct().
From Deepanshu Kartikey.
2) Limit XFRMA_TFCPAD to a sensible maximum (max IP length, 64k) since
u32 is excessive for traffic flow confidentiality padding.
From David Ahern.
3) Add a new netlink message XFRM_MSG_MIGRATE_STATE that
allows migrating individual IPsec SAs independently of
their policies. The existing XFRM_MSG_MIGRATE is tightly coupled
to policy+SA migration, lacks SPI for unique SA identification,
and cannot express reqid changes or migrate Transport mode
selectors. The new interface identifies the SA via SPI and mark,
supports reqid changes, address family changes, encap removal,
and uses an atomic create+install flow under x->lock to prevent
SN/IV reuse during AEAD SA migration.
From Antony Antony.
* tag 'ipsec-next-2026-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next:
xfrm: add documentation for XFRM_MSG_MIGRATE_STATE
xfrm: restrict netlink attributes for XFRM_MSG_MIGRATE_STATE
xfrm: add XFRM_MSG_MIGRATE_STATE for single SA migration
xfrm: make xfrm_dev_state_add xuo parameter const
xfrm: extract address family and selector validation helpers
xfrm: refactor XFRMA_MTIMER_THRESH validation into a helper
xfrm: move encap and xuo into struct xfrm_migrate
xfrm: add error messages to state migration
xfrm: add state synchronization after migration
xfrm: check family before comparing addresses in migrate
xfrm: split xfrm_state_migrate into create and install functions
xfrm: rename reqid in xfrm_migrate
xfrm: fix NAT-related field inheritance in SA migration
xfrm: allow migration from UDP encapsulated to non-encapsulated ESP
xfrm: add extack to xfrm_init_state
xfrm: remove redundant assignments
xfrm: Reject excessive values for XFRMA_TFCPAD
xfrm: cleanup error path in xfrm_add_policy()
====================
Link: https://patch.msgid.link/20260612074725.1760473-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 741a11d9e4 ("net: ipv6: Add RT6_LOOKUP_F_IFACE flag if oif is
set") made the kernel honor the oif parameter when specified as part of
output route lookup:
# ip route add 2001:db8:1::/64 dev dummy1
# ip route add ::/0 dev dummy2
# ip route get 2001:db8:1::1 oif dummy2 fibmatch
default dev dummy2 metric 1024 pref medium
Due to regression reports, the behavior was partially reverted in commit
d46a9d678e ("net: ipv6: Dont add RT6_LOOKUP_F_IFACE flag if saddr
set") to only honor the oif if source address is not specified:
# ip route get 2001:db8:1::1 from 2001:db8:2::1 oif dummy2 fibmatch
2001:db8:1::/64 dev dummy1 metric 1024 pref medium
That is, when source address is specified, the kernel will choose the
most specific route even if its nexthop device does not match the
specified oif.
This creates a problem for multipath routes. After looking up a route,
when source address is not specified, the kernel will choose a nexthop
whose nexthop device matches the specified oif:
# sysctl -wq net.ipv6.conf.all.forwarding=1
# ip route add 2001:db8:10::/64 nexthop via fe80::1 dev dummy1 nexthop via fe80::2 dev dummy2
# for i in {1..100}; do ip route get 2001:db8:10::${i} oif dummy2; done | grep -o dummy[0-9] | sort | uniq -c
100 dummy2
But will disregard the oif when source address is specified despite the
fact that a matching nexthop exists:
# for i in {1..100}; do ip route get 2001:db8:10::${i} from 2001:db8:2::1 oif dummy2; done | grep -o dummy[0-9] | sort | uniq -c
53 dummy1
47 dummy2
This behavior differs from IPv4:
# ip address add 192.0.2.1/32 dev lo
# ip route add 198.51.100.0/24 nexthop via inet6 fe80::1 dev dummy1 nexthop via inet6 fe80::2 dev dummy2
# for i in {1..100}; do ip route get 198.51.100.${i} from 192.0.2.1 oif dummy2; done | grep -o dummy[0-9] | sort | uniq -c
100 dummy2
What happens is that fib6_table_lookup() returns a route with a matching
nexthop device (assuming it exists):
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:10::${i} from 2001:db8:2::1 oif dummy2; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy2
But it is later overwritten during path selection in fib6_select_path()
which instead chooses a nexthop according to the calculated hash.
Solve this by telling fib6_select_path() to skip path selection if we
have an oif match during output route lookup (iif being
LOOPBACK_IFINDEX).
Behavior after the change:
# sysctl -wq net.ipv6.conf.all.forwarding=1
# ip route add 2001:db8:10::/64 nexthop via fe80::1 dev dummy1 nexthop via fe80::2 dev dummy2
# for i in {1..100}; do ip route get 2001:db8:10::${i} from 2001:db8:2::1 oif dummy2; done | grep -o dummy[0-9] | sort | uniq -c
100 dummy2
Note that enabling forwarding is only needed because we did not add
neighbor entries for the gateway addresses. When forwarding is disabled
and CONFIG_IPV6_ROUTER_PREF is not enabled in kernel config, the kernel
will treat non-existing neighbor entries as errors and perform
round-robin between the nexthops:
# sysctl -wq net.ipv6.conf.all.forwarding=0
# for i in {1..100}; do ip route get 2001:db8:10::${i} from 2001:db8:2::1 oif dummy2; done | grep -o dummy[0-9] | sort | uniq -c
50 dummy1
50 dummy2
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260611154605.992528-3-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently, when using multipath routes without nexthop objects,
fib6_table_lookup() selects the nexthop with the highest score. This
means that when both a source address and an oif are specified, the
nexthop that is chosen is the one that matches in terms of oif:
# sysctl -wq net.ipv6.conf.all.forwarding=1
# ip address add 2001:db8:2::1/64 dev lo
# ip route add 2001:db8:10::/64 nexthop via fe80::1 dev dummy1 nexthop via fe80::2 dev dummy2
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:10::${i} from 2001:db8:2::1 oif dummy1; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy1
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:10::${i} from 2001:db8:2::1 oif dummy2; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy2
When using nexthop objects, fib6_table_lookup() selects the first
matching nexthop and not necessarily the one with the highest score:
# ip nexthop add id 1 via fe80::1 dev dummy1
# ip nexthop add id 2 via fe80::2 dev dummy2
# ip nexthop add id 3 group 1/2
# ip route add 2001:db8:20::/64 nhid 3
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:20::${i} from 2001:db8:2::1 oif dummy1; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy1
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:20::${i} from 2001:db8:2::1 oif dummy2; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy1
This is not very significant right now because the nexthop is later
overwritten during path selection in fib6_select_path(). However, the
next patch is going to skip path selection when we have an oif match
during output route lookup.
As a preparation for this change, align the nexthop object behavior with
the legacy one and make sure that fib6_table_lookup() always selects the
best matching nexthop. Do that by always returning 0 from
rt6_nh_find_match() in order not to terminate the loop in
nexthop_for_each_fib6_nh() and storing in arg->nh the best matching
nexthop so far.
Behavior after the change:
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:20::${i} from 2001:db8:2::1 oif dummy1; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy1
# perf record -e fib6:fib6_table_lookup -- bash -c "for i in {1..100}; do ip route get 2001:db8:20::${i} from 2001:db8:2::1 oif dummy2; done > /dev/null"
# perf script | grep -o dummy[0-9] | sort | uniq -c
100 dummy2
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260611154605.992528-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
/proc/net/igmp6 walks IPv6 multicast memberships under RCU and
prints mca_flags without holding idev->mc_lock. The multicast paths
update the field while holding idev->mc_lock.
Annotate this intentional lockless snapshot with READ_ONCE() and the
matching writers with WRITE_ONCE().
Signed-off-by: Yuyang Huang <sigefriedhyy@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260609081113.7613-2-sigefriedhyy@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
xfrm async resumption hold skb->dev refcnt until after transport_finish.
However, xfrm_rcv_cb may modify skb->dev to tunnel dev without taking
device reference, such as vti_rcv_cb. The subsequent async resumption
will decrement the tunnel device's reference count, which lead to uaf
of tunnel dev and refcnt leak of orig dev as below:
unregister_netdevice: waiting for vti1 to become free. Usage count = -2
Stash the original skb->dev to fix refcnt imbalance. The new skb->dev set
by xfrm_rcv_cb can race with device teardown. Extend rcu protection over
xfrm_rcv_cb and transport_finish to prevent races.
Fixes: 1c428b0384 ("xfrm: hold dev ref until after transport_finish NF_HOOK")
Reported-by: Xu Chunxiao <xuchunxiao3@huawei.com>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Cross-merge networking fixes after downstream PR (net-7.1-rc8).
Conflicts:
drivers/net/ethernet/wangxun/txgbe/txgbe_aml.c
f67aead16e ("net: txgbe: rework service event handling")
57d39faed4 ("net: txgbe: improve functions of AML 40G devices")
net/rds/info.c
512db8267b ("rds: mark snapshot pages dirty in rds_info_getsockopt()")
6e94eeb2a2 ("rds: convert to getsockopt_iter")
Adjacent changes:
include/net/sock.h
1ee90b77b7 ("net: guard timestamp cmsgs to real error queue skbs")
f0de88303d ("net: make is_skb_wmem() available to modules")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
