linux-stable.git/net, branch v6.6.142

net: gro: don't merge zcopy skbs

2026-06-01T15:43:16+00:00

[ Upstream commit 4db79a322db8c97f7b73b8a347395ef4d685eb40 ]

skb_gro_receive() can currently copy frags between the source and GRO
skb, without checking the zerocopy status, and in particular the
SKBFL_MANAGED_FRAG_REFS flag.

When SKBFL_MANAGED_FRAG_REFS is set, the skb doesn't hold a reference
on the pages in shinfo->frags. Appending those frags to another skb's
frags without fixing up the page refcount can lead to UAF.

When either the last skb in the GRO chain (the one we would append
frags to) or the source skb is zerocopy, don't merge the skbs.

Fixes: 753f1ca4e1e5 ("net: introduce managed frags infrastructure")
Reported-by: Huzaifa Sidhpurwala 
Signed-off-by: Sabrina Dubroca 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/c3b7f906bbfcbdfd7b4fa9d6c18a438870df85be.1779307748.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

bpf, skmsg: fix verdict sk_data_ready racing with ktls rx

2026-06-01T15:43:15+00:00

[ Upstream commit ddf8029623a1af20e984c040e89ff918158397ab ]

sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and
defers to psock->saved_data_ready when a TLS RX context is present,
avoiding a conflict with the TLS strparser's ownership of the receive
queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types
with ktls").

sk_psock_verdict_data_ready() has no equivalent guard.  When a socket
is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is
configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready
as rx_ctx->saved_data_ready.  On data arrival:

  tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready
    -> saved_data_ready() = sk_psock_verdict_data_ready()
      -> tcp_read_skb() drains sk_receive_queue via __skb_unlink()
         without calling tcp_eat_skb(), so copied_seq is not advanced.

tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls
tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and
returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned
(potentially freed) skb.  tls_decrypt_sg() subsequently walks that
frag_list: use-after-free.

Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context
is present, call psock->saved_data_ready (sock_def_readable) to wake
recv() waiters and return immediately, leaving the receive queue
untouched.  TLS retains sole ownership of the queue and decrypts the
record normally through tls_sw_recvmsg().

Fixes: ef5659280eb1 ("bpf, sockmap: Allow skipping sk_skb parser program")
Signed-off-by: Xingwang Xiang 
Link: https://patch.msgid.link/20260517145630.20521-2-v3rdant.xiang@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

bridge: mcast: Fix a possible use-after-free when removing a bridge port

2026-06-01T15:43:14+00:00

[ Upstream commit 4df78ff02629c7729168f0696a7a2123c389818d ]

When per-VLAN multicast snooping is enabled, the bridge iterates over
all the bridge ports, disables the per-port multicast context on each
port and enables the per-{port, VLAN} multicast contexts instead. The
reverse happens when per-VLAN multicast snooping is disabled.

When global multicast snooping is enabled, the bridge iterates over all
the bridge ports and enables the per-port multicast context on each
port. The reverse happens when multicast snooping is disabled.

The above scheme can result in a situation where both types of contexts
(per-port and per-{port, VLAN}) are enabled on a single bridge port:

 # ip link add name br1 up type bridge mcast_snooping 1 mcast_querier 1 vlan_filtering 1
 # ip link add name dummy1 up master br1 type dummy
 # ip link set dev br1 type bridge mcast_vlan_snooping 1
 # ip link set dev br1 type bridge mcast_snooping 0
 # ip link set dev br1 type bridge mcast_snooping 1

This is not intended and it is a problem since the commit cited below.
Prior to this commit, when removing a bridge port,
br_multicast_disable_port() would disable the per-port multicast context
and the per-{port, VLAN} multicast contexts would get disabled when
flushing VLANs.

After this commit, br_multicast_disable_port() only disables the
per-port multicast context if per-VLAN multicast snooping is disabled.
If both types of contexts were enabled on the port when it was removed,
the per-port multicast context would remain enabled when freeing the
bridge port, leading to a use-after-free [1].

Fix by preventing the bridge from enabling / disabling the per-port
multicast contexts when toggling global multicast snooping if per-VLAN
multicast snooping is enabled.

[1]
ODEBUG: free active (active state 0) object: ffff88810f8bda78 object type: timer_list hint: br_ip6_multicast_port_query_expired (net/bridge/br_multicast.c:1927)
WARNING: lib/debugobjects.c:629 at debug_print_object+0x1b1/0x3e0, CPU#5: swapper/5/0
[...]
Call Trace:

__debug_check_no_obj_freed (lib/debugobjects.c:1116)
kfree (mm/slub.c:2620 mm/slub.c:6250 mm/slub.c:6565)
kobject_cleanup (lib/kobject.c:689)
rcu_do_batch (kernel/rcu/tree.c:2617)
rcu_core (kernel/rcu/tree.c:2869)
handle_softirqs (kernel/softirq.c:622)
__irq_exit_rcu (kernel/softirq.c:656 kernel/softirq.c:496 kernel/softirq.c:735)
irq_exit_rcu (kernel/softirq.c:752)
sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1061 (discriminator 47) arch/x86/kernel/apic/apic.c:1061 (discriminator 47))


Fixes: 4b30ae9adb04 ("net: bridge: mcast: re-implement br_multicast_{enable, disable}_port functions")
Reported-by: syzbot+ae231e0552fa77b26ea1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/87qznowlfs.ffs@tglx/
Reported-by: Thomas Gleixner 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: Ido Schimmel 
Link: https://patch.msgid.link/20260517121122.188333-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: bridge: Flush multicast groups when snooping is disabled

2026-06-01T15:43:14+00:00

[ Upstream commit 68800bbf583f26f71491141e4b3c8582f9cfcbde ]

When forwarding multicast packets, the bridge takes MDB into account when
IGMP / MLD snooping is enabled. Currently, when snooping is disabled, the
MDB is retained, even though it is not used anymore.

At the same time, during the time that snooping is disabled, the IGMP / MLD
control packets are obviously ignored, and after the snooping is reenabled,
the administrator has to assume it is out of sync. In particular, missed
join and leave messages would lead to traffic being forwarded to wrong
interfaces.

Keeping the MDB entries around thus serves no purpose, and just takes
memory. Note also that disabling per-VLAN snooping does actually flush the
relevant MDB entries.

This patch flushes non-permanent MDB entries as global snooping is
disabled.

Signed-off-by: Petr Machata 
Reviewed-by: Ido Schimmel 
Acked-by: Nikolay Aleksandrov 
Link: https://patch.msgid.link/5e992df1bb93b88e19c0ea5819e23b669e3dde5d.1761228273.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 4df78ff02629 ("bridge: mcast: Fix a possible use-after-free when removing a bridge port")
Signed-off-by: Sasha Levin

tls: Preserve sk_err across recvmsg() when data has been copied

2026-06-01T15:43:13+00:00

[ Upstream commit f508262ae9f21fe0e6c0749948b9dc7dd5a62a70 ]

The sk_err check in tls_rx_rec_wait() consumes the error via
sock_error(), which clears sk_err atomically. When the caller
(tls_sw_recvmsg, tls_sw_splice_read, or tls_sw_read_sock) already
has bytes copied to userspace, it returns those bytes and discards
the error from this call. sk_err is now zero on the socket, so the
next read syscall observes only RCV_SHUTDOWN and reports a clean
EOF instead of the actual error (typically -ECONNRESET).

The race is reachable when tls_read_flush_backlog()'s periodic
sk_flush_backlog() triggers tcp_reset() in the middle of a
multi-record read.

Pass a has_copied flag to tls_rx_rec_wait(). When has_copied is
false, consume sk_err via sock_error() as before. When has_copied
is true, report the error from READ_ONCE() but leave sk_err set:
the caller returns the byte count and discards the err from this
call, and the next read syscall surfaces the preserved sk_err. This
mirrors the tcp_recvmsg() preserve-and-surface pattern.

The decrypt-abort path is unaffected: tls_err_abort() raises
sk_err to EBADMSG after tls_rx_rec_wait() returns, and nothing
on the caller's return path consumes it, so the EBADMSG surfaces
on the next read.

tls_sw_splice_read() passes has_copied=false: it processes
one record per call, so no bytes have been copied within the
function when tls_rx_rec_wait() runs. A reset that arrives
between iterations of splice_direct_to_actor() (the sendfile()
path) is still consumed by sock_error() in the later call, and the
outer loop returns the prior iterations' byte count and drops the
error. tcp_splice_read() exhibits the same pattern at the iteration
boundary; addressing it belongs at the splice_direct_to_actor()
layer and is out of scope here.

Fixes: c46b01839f7a ("tls: rx: periodically flush socket backlog")
Suggested-by: Jakub Kicinski 
Signed-off-by: Chuck Lever 
Link: https://patch.msgid.link/20260513125825.205189-1-cel@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: tls: prevent chain-after-chain in plain text SG

2026-06-01T15:43:13+00:00

[ Upstream commit ff26a0e8377dec07e4a7230db7675bed1b9a6d03 ]

Sashiko points out that if end = 0 (start != 0) the current
code will create a chain link to content type right after
the wrap link:

  This would create a chain where the wrap link points directly
  to another chain link. The scatterlist API sg_next iterator
  does not recursively resolve consecutive chain links.

meaning this is illegal input to crypto.

The wrapping link is unnecessary if end = 0. end is the entry after
the last one used so end = 0 means there's nothing pushed after
the wrap:

   end         start            i
    v            v              v
  [   ]...[   ][ d ][ d ][ d ][ d ][rsv for wrap]

Skip the wrapping in this case.

TLS 1.3 can use the "wrapping slot" for it's chaining if end = 0.
This avoids the chain-after-chain.

Move the wrap chaining before marking END and chaining off content
type, that feels like more logical ordering to me, but should not
matter from functional perspective.

Reported-by: Sashiko 
Fixes: 9aaaa56845a0 ("bpf: Sockmap/tls, skmsg can have wrapped skmsg that needs extra chaining")
Signed-off-by: Jakub Kicinski 
Link: https://patch.msgid.link/20260511174920.433155-3-kuba@kernel.org
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring

2026-06-01T15:43:13+00:00

[ Upstream commit 285943c6e7ca309bbea84b253745154241d9788a ]

When an sk_msg scatterlist ring wraps (sg.end < sg.start),
tls_push_record() chains the tail portion of the ring to the head
using sg_chain(). An extra entry in the sg array is reserved for
this:

  struct sk_msg_sg {
        [...]
        /* The extra two elements:
         * 1) used for chaining the front and sections when the list becomes
         *    partitioned (e.g. end < start). The crypto APIs require the
         *    chaining;
         * 2) to chain tailer SG entries after the message.
         */
        struct scatterlist              data[MAX_MSG_FRAGS + 2];

The current code uses MAX_SKB_FRAGS + 1 as the ring size:

    sg_chain(&msg_pl->sg.data[msg_pl->sg.start],
             MAX_SKB_FRAGS - msg_pl->sg.start + 1,
             msg_pl->sg.data);

This places the chain pointer at

  sg_chain(data[start], (MAX_SKB_FRAGS - msg_start + 1) .. =
  &data[start] + (MAX_SKB_FRAGS - msg_start + 1) - 1 =
  data[start + (MAX_SKB_FRAGS - start + 1) - 1] =
  data[MAX_SKB_FRAGS]

instead of the true last entry. This is likely due to a "race" of
the commit under Fixes landing close to
commit 031097d9e079 ("bpf: sk_msg, zap ingress queue on psock down")

Convert to ARRAY_SIZE and drop the data[start] / - start (as suggested
by Sabrina).

Reported-by: 钱一铭 
Fixes: 9aaaa56845a0 ("bpf: Sockmap/tls, skmsg can have wrapped skmsg that needs extra chaining")
Signed-off-by: Jakub Kicinski 
Reviewed-by: Sabrina Dubroca 
Link: https://patch.msgid.link/20260511174920.433155-2-kuba@kernel.org
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot

2026-06-01T15:43:13+00:00

[ Upstream commit 277740023def559a4a2ddc3e8e784ee37a0f16a9 ]

On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is
reserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt()
populates V2 entries starting at index 1, so when no V1 device is
selected slot 0 is left in its kzalloc()'ed state with ism_dev[0] ==
NULL and ism_chid[0] == 0.

smc_v2_determine_accepted_chid() then matches the peer's CHID against
the array starting from index 0 using the CHID alone. A malicious
peer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches
the empty slot, ini->ism_selected becomes 0, and the subsequent
ism_dev[0]->lgr_lock dereference in smc_conn_create() faults at
offsetof(struct smcd_dev, lgr_lock) == 0x68:

  BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0
  Write of size 4 at addr 0000000000000068 by task exploit/144
  Call Trace:
   _raw_spin_lock_bh
   smc_conn_create (net/smc/smc_core.c:1997)
   __smc_connect (net/smc/af_smc.c:1447)
   smc_connect (net/smc/af_smc.c:1720)
   __sys_connect
   __x64_sys_connect
   do_syscall_64

Require ism_dev[i] to be non-NULL before accepting a CHID match.

Fixes: a7c9c5f4af7f ("net/smc: CLC accept / confirm V2")
Reported-by: Weiming Shi 
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Xiang Mei 
Link: https://patch.msgid.link/20260511062138.2839584-1-xmei5@asu.edu
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

ethtool: fix ethnl_bitmap32_not_zero() bit interval semantics

2026-06-01T15:43:13+00:00

[ Upstream commit 3d042592ebd4c7e44974d556de0b727cb7db4dab ]

ethnl_bitmap32_not_zero() should return true if some bit in [start, end)
is set:

- Fix inverted memchr_inv() sense: return true when the scan finds a
  non-zero byte, not when the middle words are all zero.
- Return false for an empty interval (end <= start).
- When end is 32-bit aligned, indices in [start, end) do not include any
  bits from map[end_word]; return false after earlier checks found no
  non-zero data.

Fixes: 10b518d4e6dd ("ethtool: netlink bitset handling")
Signed-off-by: Chenguang Zhao 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint

2026-06-01T15:43:13+00:00

[ Upstream commit 7bf563badd37cb796df5477d2b78bb64148a1268 ]

The smc_msg_event tracepoint class, shared by smc_tx_sendmsg and
smc_rx_recvmsg, unconditionally dereferences smc->conn.lnk:

	__string(name, smc->conn.lnk->ibname)

conn->lnk is only set for SMC-R; for SMC-D it is NULL. Other code on
these paths already handles this (e.g. !conn->lnk in
SMC_STAT_RMB_TX_SIZE_SMALL()). With the tracepoint enabled, the first
sendmsg()/recvmsg() on an SMC-D socket crashes:

  Oops: general protection fault, probably for non-canonical address
  KASAN: null-ptr-deref in range [...]
  RIP: 0010:strlen+0x1e/0xa0
  Call Trace:
   trace_event_raw_event_smc_msg_event (net/smc/smc_tracepoint.h:44)
   smc_rx_recvmsg (net/smc/smc_rx.c:515)
   smc_recvmsg (net/smc/af_smc.c:2859)
   __sys_recvfrom (net/socket.c:2315)
   __x64_sys_recvfrom (net/socket.c:2326)
   do_syscall_64

The faulting address 0x3e0 is offsetof(struct smc_link, ibname),
confirming the NULL ->lnk deref. Enabling the tracepoint requires
root, but the trigger itself is unprivileged: socket(AF_SMC, ...) has
no capability check, and SMC-D negotiation needs no admin step on
s390 or on x86 with the loopback ISM device loaded.

Log an empty device name for SMC-D instead of dereferencing NULL.

Fixes: aff3083f10bf ("net/smc: Introduce tracepoints for tx and rx msg")
Reported-by: Weiming Shi 
Signed-off-by: Xiang Mei 
Reviewed-by: Dust Li 
Reviewed-by: Sidraya Jayagond 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin