linux-stable.git/net, branch v6.18.27

netfilter: reject zero shift in nft_bitwise

2026-05-07T04:12:03+00:00

commit fe11e5c40817b84abaa5d83bfb6586d8412bfd07 upstream.

Reject zero shift operands for nft_bitwise left and right shift
expressions during initialization.

The carry propagation logic computes the carry from the adjacent 32-bit
word using BITS_PER_TYPE(u32) - shift. A zero shift operand turns this
into a 32-bit shift, which is undefined behaviour.

Reject zero shift operands in the control plane, alongside the existing
check for values greater than or equal to 32, so malformed rules never
reach the packet path.

Fixes: 567d746b55bc ("netfilter: bitwise: add support for shifts.")
Cc: stable@kernel.org
Reported-by: Yuan Tan 
Reported-by: Yifan Wu 
Reported-by: Juefei Pu 
Reported-by: Xin Liu 
Signed-off-by: Kai Ma 
Signed-off-by: Ren Wei 
Reviewed-by: Fernando Fernandez Mancera 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels

2026-05-07T04:12:03+00:00

commit f9c52a6ba9780bd27e0bf4c044fd91c13c778b6e upstream.

seg6_input_core() and rpl_input() call ip6_route_input() which sets a
NOREF dst on the skb, then pass it to dst_cache_set_ip6() invoking
dst_hold() unconditionally.
On PREEMPT_RT, ksoftirqd is preemptible and a higher-priority task can
release the underlying pcpu_rt between the lookup and the caching
through a concurrent FIB lookup on a shared nexthop.
Simplified race sequence:

  ksoftirqd/X                       higher-prio task (same CPU X)
  -----------                       --------------------------------
  seg6_input_core(,skb)/rpl_input(skb)
    dst_cache_get()
      -> miss
    ip6_route_input(skb)
      -> ip6_pol_route(,skb,flags)
         [RT6_LOOKUP_F_DST_NOREF in flags]
        -> FIB lookup resolves fib6_nh
           [nhid=N route]
        -> rt6_make_pcpu_route()
           [creates pcpu_rt, refcount=1]
             pcpu_rt->sernum = fib6_sernum
             [fib6_sernum=W]
           -> cmpxchg(fib6_nh.rt6i_pcpu,
                      NULL, pcpu_rt)
              [slot was empty, store succeeds]
      -> skb_dst_set_noref(skb, dst)
         [dst is pcpu_rt, refcount still 1]

                                    rt_genid_bump_ipv6()
                                      -> bumps fib6_sernum
                                         [fib6_sernum from W to Z]
                                    ip6_route_output()
                                      -> ip6_pol_route()
                                        -> FIB lookup resolves fib6_nh
                                           [nhid=N]
                                        -> rt6_get_pcpu_route()
                                             pcpu_rt->sernum != fib6_sernum
                                             [W <> Z, stale]
                                          -> prev = xchg(rt6i_pcpu, NULL)
                                          -> dst_release(prev)
                                             [prev is pcpu_rt,
                                              refcount 1->0, dead]

    dst = skb_dst(skb)
    [dst is the dead pcpu_rt]
    dst_cache_set_ip6(dst)
      -> dst_hold() on dead dst
      -> WARN / use-after-free

For the race to occur, ksoftirqd must be preemptible (PREEMPT_RT without
PREEMPT_RT_NEEDS_BH_LOCK) and a concurrent task must be able to release
the pcpu_rt. Shared nexthop objects provide such a path, as two routes
pointing to the same nhid share the same fib6_nh and its rt6i_pcpu
entry.

Fix seg6_input_core() and rpl_input() by calling skb_dst_force() after
ip6_route_input() to force the NOREF dst into a refcounted one before
caching.
The output path is not affected as ip6_route_output() already returns a
refcounted dst.

Fixes: af4a2209b134 ("ipv6: sr: use dst_cache in seg6_input")
Fixes: a7a29f9c361f ("net: ipv6: add rpl sr tunnel")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Mayer 
Reviewed-by: Simon Horman 
Reviewed-by: Justin Iurman 
Link: https://patch.msgid.link/20260421094735.20997-1-andrea.mayer@uniroma2.it
Signed-off-by: Paolo Abeni 
Signed-off-by: Greg Kroah-Hartman

ipv6: rpl: reserve mac_len headroom when recompressed SRH grows

2026-05-07T04:12:02+00:00

commit 9e6bf146b55999a095bb14f73a843942456d1adc upstream.

ipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps
the next segment into ipv6_hdr->daddr, recompresses, then pulls the old
header and pushes the new one plus the IPv6 header back.  The
recompressed header can be larger than the received one when the swap
reduces the common-prefix length the segments share with daddr (CmprI=0,
CmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes).

pskb_expand_head() was gated on segments_left == 0, so on earlier
segments the push consumed unchecked headroom.  Once skb_push() leaves
fewer than skb->mac_len bytes in front of data,
skb_mac_header_rebuild()'s call to:

	skb_set_mac_header(skb, -skb->mac_len);

will store (data - head) - mac_len into the u16 mac_header field, which
wraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB
past skb->head.

A single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two
segment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one
pass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv.

Fix this by expanding the head whenever the remaining room is less than
the push size plus mac_len, and request that much extra so the rebuilt
MAC header fits afterwards.

Fixes: 8610c7c6e3bd ("net: ipv6: add support for rpl sr exthdr")
Cc: stable 
Reported-by: Anthropic
Signed-off-by: Greg Kroah-Hartman 
Link: https://patch.msgid.link/2026042133-gout-unvented-1bd9@gregkh
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: qrtr: ns: Limit the total number of nodes

2026-05-07T04:12:01+00:00

[ Upstream commit 27d5e84e810b0849d08b9aec68e48570461ce313 ]

Currently, the nameserver doesn't limit the number of nodes it handles.
This can be an attack vector if a malicious client starts registering
random nodes, leading to memory exhaustion.

Hence, limit the maximum number of nodes to 64. Note that, limit of 64 is
chosen based on the current platform requirements. If requirement changes
in the future, this limit can be increased.

Cc: stable@vger.kernel.org
Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Manivannan Sadhasivam 
Link: https://patch.msgid.link/20260409-qrtr-fix-v3-4-00a8a5ff2b51@oss.qualcomm.com
Signed-off-by: Jakub Kicinski 
[ dropped comment/define changes for missing QRTR_NS_MAX_SERVERS/LOOKUPS prereqs and kept plain kzalloc instead of kzalloc_obj ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

net: qrtr: ns: Limit the maximum number of lookups

2026-05-07T04:12:01+00:00

[ Upstream commit 5640227d9a21c6a8be249a10677b832e7f40dc55 ]

Current code does no bound checking on the number of lookups a client can
perform. Though the code restricts the lookups to local clients, there is
still a possibility of a malicious local client sending a flood of
NEW_LOOKUP messages over the same socket.

Fix this issue by limiting the maximum number of lookups to 64 globally.
Since the nameserver allows only atmost one local observer, this global
lookup count will ensure that the lookups stay within the limit.

Note that, limit of 64 is chosen based on the current platform
requirements. If requirement changes in the future, this limit can be
increased.

Cc: stable@vger.kernel.org
Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Manivannan Sadhasivam 
Link: https://patch.msgid.link/20260409-qrtr-fix-v3-2-00a8a5ff2b51@oss.qualcomm.com
Signed-off-by: Jakub Kicinski 
[ adapted comment block to only mention QRTR_NS_MAX_LOOKUPS and kept kzalloc() instead of kzalloc_obj() due to missing prerequisite commits ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

net: qrtr: ns: Limit the maximum server registration per node

2026-05-07T04:12:01+00:00

[ Upstream commit d5ee2ff98322337951c56398e79d51815acbf955 ]

Current code does no bound checking on the number of servers added per
node. A malicious client can flood NEW_SERVER messages and exhaust memory.

Fix this issue by limiting the maximum number of server registrations to
256 per node. If the NEW_SERVER message is received for an old port, then
don't restrict it as it will get replaced. While at it, also rate limit
the error messages in the failure path of qrtr_ns_worker().

Note that the limit of 256 is chosen based on the current platform
requirements. If requirement changes in the future, this limit can be
increased.

Cc: stable@vger.kernel.org
Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Reported-by: Yiming Qian 
Reviewed-by: Simon Horman 
Signed-off-by: Manivannan Sadhasivam 
Link: https://patch.msgid.link/20260409-qrtr-fix-v3-1-00a8a5ff2b51@oss.qualcomm.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

seg6: fix seg6 lwtunnel output redirect for L2 reduced encap mode

2026-05-07T04:11:59+00:00

commit ade67d5f588832c7ba131aadd4215a94ce0a15c8 upstream.

When SEG6_IPTUN_MODE_L2ENCAP_RED (L2ENCAP_RED) was introduced, the
condition in seg6_build_state() that excludes L2 encap modes from
setting LWTUNNEL_STATE_OUTPUT_REDIRECT was not updated to account for
the new mode.
As a consequence, L2ENCAP_RED routes incorrectly trigger seg6_output()
on the output path, where the packet is silently dropped because
skb_mac_header_was_set() fails on L3 packets.

Extend the check to also exclude L2ENCAP_RED, consistent with L2ENCAP.

Fixes: 13f0296be8ec ("seg6: add support for SRv6 H.L2Encaps.Red behavior")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Mayer 
Reviewed-by: Justin Iurman 
Link: https://patch.msgid.link/20260418162838.31979-1-andrea.mayer@uniroma2.it
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

rxgk: Fix potential integer overflow in length check

2026-05-07T04:11:59+00:00

commit 6929350080f4da292d111a3b33e53138fee51cec upstream.

Fix potential integer overflow in rxgk_extract_token() when checking the
length of the ticket.  Rather than rounding up the value to be tested
(which might overflow), round down the size of the available data.

Fixes: 2429a1976481 ("rxrpc: Fix untrusted unsigned subtract")
Closes: https://sashiko.dev/#/patchset/20260408121252.2249051-1-dhowells%40redhat.com
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: Jeffrey Altman 
cc: Simon Horman 
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/20260422161438.2593376-6-dhowells@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: hci_event: fix potential UAF in SSP passkey handlers

2026-05-07T04:11:56+00:00

commit 85fa3512048793076eef658f66489112dcc91993 upstream.

hci_conn lookup and field access must be covered by hdev lock in
hci_user_passkey_notify_evt() and hci_keypress_notify_evt(), otherwise
the connection can be freed concurrently.

Extend the hci_dev_lock critical section to cover all conn usage in both
handlers.

Keep the existing keypress notification behavior unchanged by routing
the early exits through a common unlock path.

Fixes: 92a25256f142 ("Bluetooth: mgmt: Implement support for passkey notification")
Cc: stable@vger.kernel.org
Signed-off-by: Shuvam Pandey 
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Greg Kroah-Hartman

tcp: call sk_data_ready() after listener migration

2026-05-07T04:11:55+00:00

commit 3864c6ba1e041bc75342353a70fa2a2c6f909923 upstream.

When inet_csk_listen_stop() migrates an established child socket from
a closing listener to another socket in the same SO_REUSEPORT group,
the target listener gets a new accept-queue entry via
inet_csk_reqsk_queue_add(), but that path never notifies the target
listener's waiters. A nonblocking accept() still works because it
checks the queue directly, but poll()/epoll_wait() waiters and
blocking accept() callers can also remain asleep indefinitely.

Call READ_ONCE(nsk->sk_data_ready)(nsk) after a successful migration
in inet_csk_listen_stop().

However, after inet_csk_reqsk_queue_add() succeeds, the ref acquired
in reuseport_migrate_sock() is effectively transferred to
nreq->rsk_listener. Another CPU can then dequeue nreq via accept()
or listener shutdown, hit reqsk_put(), and drop that listener ref.
Since listeners are SOCK_RCU_FREE, wrap the post-queue_add()
dereferences of nsk in rcu_read_lock()/rcu_read_unlock(), which also
covers the existing sock_net(nsk) access in that path.

The reqsk_timer_handler() path does not need the same changes for two
reasons: half-open requests become readable only after the final ACK,
where tcp_child_process() already wakes the listener; and once nreq is
visible via inet_ehash_insert(), the success path no longer touches
nsk directly.

Fixes: 54b92e841937 ("tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues.")
Cc: stable@vger.kernel.org
Suggested-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Signed-off-by: Zhenzhong Wu 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20260422024554.130346-2-jt26wzz@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman