linux-stable.git/net, branch v6.6.151

sctp: close UDP tunnel sockets during netns teardown

2026-08-09T18:22:04+00:00

[ Upstream commit ffb2bd7ade36ec4da32c46a6eddbf4515316d08c ]

proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when
net.sctp.udp_port is set, and stops/restarts them when the sysctl value
changes. The netns exit path does not stop these sockets, so a namespace
can be torn down while its SCTP UDP tunnel sockets are still installed.

Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering
the per-net sysctl table. This prevents new sysctl writes from racing in
while the sockets are being released, and closes the sockets before the
control socket is destroyed.

Fixes: 046c052b475e ("sctp: enable udp tunneling socks")
Cc: stable@vger.kernel.org
Reported-by: Sashiko 
Closes: https://sashiko.dev/#/patchset/b9f1f02b0780ad6a719e2413f5f0bb8eb7702d94.1782585631.git.roxy520tt%40gmail.com
Signed-off-by: Zhiling Zou 
Signed-off-by: Ren Wei 
Acked-by: Xin Long 
Link: https://patch.msgid.link/6dab75f22855cb219e2e30a5497cab03b970ab91.1784033357.git.roxy520tt@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: pm: userspace: fix use-after-free in get_local_id

2026-08-09T18:22:04+00:00

[ Upstream commit 9bc6d5e4ca9f3cbb41d43400b3a31cb0403796c9 ]

In mptcp_pm_userspace_get_local_id(), the address entry is looked up under
spinlock, but its id is read after dropping the lock. A concurrent deletion
can free the entry between the unlock and the read, leading to UAF.

The race window is narrow. It was reproduced only with a locally
constructed stress test that repeatedly overlaps an MP_JOIN SYN with a
MPTCP_PM_CMD_SUBFLOW_DESTROY request.

However, the KASAN report below confirms that the race is reachable:

  [  666.319376] BUG: KASAN: slab-use-after-free in mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
  [  666.319386] Read of size 1 at addr ffff888124845610 by task swapper/0/0
  ...
  [  666.319401] Call Trace:
  [  666.319405]  
  [  666.319408]  dump_stack_lvl+0x53/0x70
  [  666.319412]  print_address_description.constprop.0+0x2c/0x3b0
  [  666.319418]  print_report+0xbe/0x2b0
  [  666.319421]  ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
  [  666.319423]  kasan_report+0xce/0x100
  [  666.319426]  ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
  [  666.319429]  mptcp_userspace_pm_get_local_id+0x1dc/0x1f0
  [  666.319433]  mptcp_pm_get_local_id+0x371/0x440
  ...
  [  666.319821] Allocated by task 45539:
  [  666.319844]  kasan_save_stack+0x33/0x60
  [  666.319855]  kasan_save_track+0x14/0x30
  [  666.319858]  __kasan_kmalloc+0x8f/0xa0
  [  666.319863]  __kmalloc_noprof+0x1e7/0x520
  [  666.319867]  sock_kmalloc+0xdf/0x130
  [  666.319885]  sock_kmemdup+0x1b/0x40
  [  666.319888]  mptcp_userspace_pm_append_new_local_addr+0x261/0x500
  [  666.319910]  mptcp_pm_nl_announce_doit+0x16a/0x610
  ...
  [  666.319967] Freed by task 45560:
  [  666.319988]  kasan_save_stack+0x33/0x60
  [  666.319991]  kasan_save_track+0x14/0x30
  [  666.319994]  kasan_save_free_info+0x3b/0x60
  [  666.319998]  __kasan_slab_free+0x43/0x70
  [  666.320000]  kfree+0x166/0x440
  [  666.320003]  sock_kfree_s+0x1d/0x50
  [  666.320007]  mptcp_userspace_pm_delete_local_addr.isra.0+0x157/0x200
  [  666.320011]  mptcp_pm_nl_subflow_destroy_doit+0x51d/0xea0

Fix by copying the id into a local variable while still holding the lock,
and use -1 as a "not found" sentinel.

Fixes: f012d796a6de ("mptcp: check addrs list in userspace_pm_get_local_id")
Cc: stable@vger.kernel.org
Signed-off-by: Geliang Tang 
Tested-by: Xuanqiang Luo 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260722-net-mptcp-misc-fixes-7-2-rc5-v1-2-6fb595bc86ef@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: pm: use addr entry for get_local_id

2026-08-09T18:22:04+00:00

[ Upstream commit 7462fe22cc74321eb663768848976d42eba3ddbb ]

The following code in mptcp_userspace_pm_get_local_id() that assigns "skc"
to "new_entry" is not allowed in BPF if we use the same code to implement
the get_local_id() interface of a BFP path manager:

	memset(&new_entry, 0, sizeof(struct mptcp_pm_addr_entry));
	new_entry.addr = *skc;
	new_entry.addr.id = 0;
	new_entry.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;

To solve the issue, this patch moves this assignment to "new_entry" forward
to mptcp_pm_get_local_id(), and then passing "new_entry" as a parameter to
both mptcp_pm_nl_get_local_id() and mptcp_userspace_pm_get_local_id().

No behavioural changes intended.

Signed-off-by: Geliang Tang 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20250307-net-next-mptcp-pm-reorg-v1-1-abef20ada03b@kernel.org
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 9bc6d5e4ca9f ("mptcp: pm: userspace: fix use-after-free in get_local_id")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: add mptcp_userspace_pm_lookup_addr helper

2026-08-09T18:22:04+00:00

[ Upstream commit e7b4083b90b7213902124d13fd1ed808360e32b1 ]

Like __lookup_addr() helper in pm_netlink.c, a new helper
mptcp_userspace_pm_lookup_addr() is also defined in pm_userspace.c.
It looks up the corresponding mptcp_pm_addr_entry address in
userspace_pm_local_addr_list through the passed "addr" parameter
and returns the found address entry.

This helper can be used in mptcp_userspace_pm_delete_local_addr(),
mptcp_userspace_pm_set_flags(), mptcp_userspace_pm_get_local_id()
and mptcp_userspace_pm_is_backup() to simplify the code.

Please note that with this change now list_for_each_entry() is used in
mptcp_userspace_pm_append_new_local_addr(), not list_for_each_entry_safe(),
but that's OK to do so because mptcp_userspace_pm_lookup_addr() only
returns an entry from the list, the list hasn't been modified here.

Signed-off-by: Geliang Tang 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20241213-net-next-mptcp-pm-misc-cleanup-v1-1-ddb6d00109a8@kernel.org
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 9bc6d5e4ca9f ("mptcp: pm: userspace: fix use-after-free in get_local_id")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: pm: avoid code duplication to lookup endp

2026-08-09T18:22:04+00:00

[ Upstream commit 1d7fa6ceb91fddbe38cae3521d5d1075bce6a00e ]

The helper __lookup_addr() can be used in mptcp_pm_nl_get_local_id()
and mptcp_pm_nl_is_backup() to simplify the code, and avoid code
duplication.

Co-developed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Signed-off-by: Geliang Tang 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20241115-net-next-mptcp-pm-lockless-dump-v1-2-f4a1bcb4ca2c@kernel.org
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 9bc6d5e4ca9f ("mptcp: pm: userspace: fix use-after-free in get_local_id")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

can: isotp: fix timer drain order, wakeup handling and tx_gen ordering

2026-08-09T18:22:04+00:00

commit 050f010f920da17c1044a4f174766ad553e770b6 upstream.

This patch is a follow-up to commit cf070fe33bfb ("can: isotp: serialize
TX state transitions under so->rx_lock") which addresses following
sashiko-bot findings:

- isotp_sendmsg(): drain so->txfrtimer first so a stale callback can't
  re-arm echotimer after the claim

- isotp_release(): wake so->wait after forcing ISOTP_SHUTDOWN so a
  sleeping sendmsg() claim isn't stranded

- isotp_sendmsg(): have both wait_event_interruptible() calls in
  isotp_sendmsg() also wake on ISOTP_SHUTDOWN and do not return claim to
  IDLE to avoid corrupting a concurrent isotp_release() process.

- isotp_sendmsg(): handle potential claim of a new transfer when
  the wait_event_interruptible() call returns in CAN_ISOTP_WAIT_TX_DONE
  mode. Don't touch timers and states of the new transfer if a new thread
  incremented so->tx_gen before getting the lock at err_event_drop.

- isotp_sendmsg(): handle a stuck can_send() and omit timer and state
  changes if a new transfer was claimed. wait_tx_done() returns the error
  recorded in so->tx_result[], tagged with the caller's own generation.

- isotp_tx_timeout(): on a claimed timeout, record the ECOMM error for
  the timed-out transfer's own generation in so->tx_result[]; sk->sk_err
  is raised unconditionally, same as every other error path here.

- isotp_tx_gen_done()/isotp_tx_timeout(): always read tx.state (acquire)
  before tx_gen - the reverse order let a weakly ordered CPU pair a fresh
  tx.state with a stale tx_gen/tx_result slot.

- isotp_sendmsg(): wait_tx_done: drain sk_err via sock_error() once we
  have read the result from so->tx_result[], so an already-reported error
  doesn't stay latched for a later poll()/SO_ERROR.

Also align the remaining lock-free so->tx.state/rx.state/cfecho accesses
and use skb->hash as unique loopback echo frame indicator.

Fixes: cf070fe33bfb ("can: isotp: serialize TX state transitions under so->rx_lock")
Signed-off-by: Oliver Hartkopp 
Link: https://patch.msgid.link/20260724181525.43556-1-socketcan@hartkopp.net
Cc: stable@kernel.org
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Greg Kroah-Hartman

can: use skb hash instead of private variable in headroom

2026-08-09T18:22:03+00:00

commit d4fb6514ff8ed6912a71294e6b66a5d59ee88007 upstream.

The can_skb_priv::skbcnt variable is used to identify CAN skbs in the RX
path analogue to the skb->hash.

As the skb hash is not filled in CAN skbs move the private skbcnt value to
skb->hash and set skb->sw_hash accordingly. The skb->hash is a value used
for RPS to identify skbs. Use it as intended.

Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Oliver Hartkopp 
Link: https://patch.msgid.link/20260201-can_skb_ext-v8-1-3635d790fe8b@hartkopp.net
Signed-off-by: Paolo Abeni 
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Greg Kroah-Hartman

sctp: avoid auth_enable sysctl UAF during netns teardown

2026-08-09T18:22:03+00:00

[ Upstream commit f8d5e7846025f4ab15a461235f8ebae9094a361a ]

proc_sctp_do_auth() updates the SCTP control socket after changing
net.sctp.auth_enable. The handler gets the per-net SCTP state from
ctl->data, so an already opened sysctl file can still target a network
namespace while that namespace is being torn down.

SCTP previously registered its per-net sysctls from sctp_defaults_init(),
while the control socket is created later from sctp_ctrlsock_init(). This
exposed a window during initialization where auth_enable was writable
before net->sctp.ctl_sock existed, and a teardown window where auth_enable
stayed writable after inet_ctl_sock_destroy() had released the control
socket.

Move the per-net SCTP sysctl registration into sctp_ctrlsock_init() after
sctp_ctl_sock_init() succeeds, and unregister the sysctl table before
destroying the control socket in sctp_ctrlsock_exit(). If sysctl
registration fails after the control socket was created, destroy the
control socket in the same init path.

Make sctp_sysctl_net_unregister() tolerate a missing header and clear the
saved pointer so init-error and exit paths can safely share the unregister
helper.

Fixes: 15649fd5415e ("sctp: sysctl: auth_enable: avoid using current->nsproxy")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan 
Reported-by: Yifan Wu 
Reported-by: Juefei Pu 
Reported-by: Xin Liu 
Co-developed-by: Qi Tang 
Signed-off-by: Qi Tang 
Signed-off-by: Zhiling Zou 
Signed-off-by: Ren Wei 
Acked-by: Xin Long 
Link: https://patch.msgid.link/390cd5e91ed60eea27b0b64d0468301a9e73b808.1784033357.git.roxy520tt@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sysctl: treewide: constify ctl_table_header::ctl_table_arg

2026-08-09T18:22:03+00:00

[ Upstream commit bfa858f220ab8c950dd3e1310fee61950d0ecdae ]

To be able to constify instances of struct ctl_tables it is necessary to
remove ways through which non-const versions are exposed from the
sysctl core.
One of these is the ctl_table_arg member of struct ctl_table_header.

Constify this reference as a prerequisite for the full constification of
struct ctl_table instances.
No functional change.

Signed-off-by: Thomas Weißschuh 
Reviewed-by: Kees Cook 
Signed-off-by: David S. Miller 
Stable-dep-of: f8d5e7846025 ("sctp: avoid auth_enable sysctl UAF during netns teardown")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: clone set on flush only

2026-08-09T18:22:03+00:00

[ Upstream commit fb7fb4016300ac622c964069e286dc83166a5d52 ]

Syzbot with fault injection triggered a failing memory allocation with
GFP_KERNEL which results in a WARN splat:

iter.err
WARNING: net/netfilter/nf_tables_api.c:845 at nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845, CPU#0: syz.0.17/5992
Modules linked in:
CPU: 0 UID: 0 PID: 5992 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845
Code: 8b 05 86 5a 4e 09 48 3b 84 24 a0 00 00 00 75 62 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 63 6d fa f7 90 <0f> 0b 90 43
+80 7c 35 00 00 0f 85 23 fe ff ff e9 26 fe ff ff 89 d9
RSP: 0018:ffffc900045af780 EFLAGS: 00010293
RAX: ffffffff89ca45bd RBX: 00000000fffffff4 RCX: ffff888028111e40
RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000
RBP: ffffc900045af870 R08: 0000000000400dc0 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff1d141db R12: ffffc900045af7e0
R13: 1ffff920008b5f24 R14: dffffc0000000000 R15: ffffc900045af920
FS:  000055557a6a5500(0000) GS:ffff888125496000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb5ea271fc0 CR3: 000000003269e000 CR4: 00000000003526f0
Call Trace:
 
 __nft_release_table+0xceb/0x11f0 net/netfilter/nf_tables_api.c:12115
 nft_rcv_nl_event+0xc25/0xdb0 net/netfilter/nf_tables_api.c:12187
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
 netlink_release+0x123b/0x1ad0 net/netlink/af_netlink.c:761
 __sock_release net/socket.c:662 [inline]
 sock_close+0xc3/0x240 net/socket.c:1455

Restrict set clone to the flush set command in the preparation phase.
Add NFT_ITER_UPDATE_CLONE and use it for this purpose, update the rbtree
and pipapo backends to only clone the set when this iteration type is
used.

As for the existing NFT_ITER_UPDATE type, update the pipapo backend to
use the existing set clone if available, otherwise use the existing set
representation. After this update, there is no need to clone a set that
is being deleted, this includes bound anonymous set.

An alternative approach to NFT_ITER_UPDATE_CLONE is to add a .clone
interface and call it from the flush set path.

Reported-by: syzbot+4924a0edc148e8b4b342@syzkaller.appspotmail.com
Fixes: 3f1d886cc7c3 ("netfilter: nft_set_pipapo: move cloning of match info to insert/removal path")
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Florian Westphal 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman