linux-stable.git/net, branch linux-6.1.y

ipv6: account for fraggap on the paged allocation path

2026-07-04T11:41:33+00:00

[ Upstream commit 736b380e28d0480c7bc3e022f1950f31fe53a7c5 ]

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 773ba4fe9104 ("ipv6:
avoid partial copy for zc"). Before commit ce650a166335 ("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: 773ba4fe9104 ("ipv6: avoid partial copy for zc")
Signed-off-by: Jungwoo Lee 
Signed-off-by: Wongi Lee 
Reviewed-by: Ido Schimmel 
Link: https://patch.msgid.link/ajFTqRljatR17fFy@DESKTOP-19IMU7U.localdomain
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

net: phonet: free phonet_device after RCU grace period

2026-07-04T11:41:33+00:00

[ Upstream commit 71de0177b28da751f407581a4515cf4d762f6296 ]

phonet_device_destroy() removes a phonet_device from the per-net device
list with list_del_rcu(), but frees it immediately. RCU readers walking
the same list can still hold a pointer to the object after it has been
removed, leading to a slab-use-after-free.

Use kfree_rcu(), matching the lifetime rule already used by
phonet_address_del() for the same object type.

Fixes: eeb74a9d45f7 ("Phonet: convert devices list to RCU")
Cc: stable@vger.kernel.org
Signed-off-by: Santosh Kalluri 
Acked-by: Rémi Denis-Courmont 
Reviewed-by: Simon Horman 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

phonet: Pass net and ifindex to phonet_address_notify().

2026-07-04T11:41:33+00:00

[ Upstream commit 68ed5c38b512b734caf3da1f87db4a99fcfe3002 ]

Currently, phonet_address_notify() fetches netns and ifindex from dev.

Once addr_doit() is converted to RCU, phonet_address_notify() will be
called outside of RCU due to GFP_KERNEL, and dev will be unavailable
there.

Let's pass net and ifindex to phonet_address_notify().

Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Signed-off-by: Paolo Abeni 
Stable-dep-of: 71de0177b28d ("net: phonet: free phonet_device after RCU grace period")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

phonet: Pass ifindex to fill_addr().

2026-07-04T11:41:33+00:00

[ Upstream commit 08a9572be36819b5d9011604edfa5db6c5062a7a ]

We will convert addr_doit() and getaddr_dumpit() to RCU, both
of which call fill_addr().

The former will call phonet_address_notify() outside of RCU
due to GFP_KERNEL, so dev will not be available in fill_addr().

Let's pass ifindex directly to fill_addr().

Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Signed-off-by: Paolo Abeni 
Stable-dep-of: 71de0177b28d ("net: phonet: free phonet_device after RCU grace period")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: fix missing wakeups in edge scenarios

2026-07-04T11:41:32+00:00

[ Upstream commit 9d8d28738f24b75616d6ca7a27cb4aed88520343 ]

The mptcp_recvmsg() can fill MPTCP socket receive queue via
mptcp_move_skbs(), but currently does not try to wakeup any listener,
because the same process is going to check the receive queue soon.

When multiple threads are reading from the same fd, the above can
cause stall. Add the missing wakeup.

Fixes: 6771bfd9ee24 ("mptcp: update mptcp ack sequence from work queue")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-1-856831229976@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: pm: fix extra_subflows underflow on userspace PM subflow creation

2026-07-04T11:41:32+00:00

[ Upstream commit 14e9fea30b68fc75b2b3d97396a7e6adb544bd2a ]

The userspace PM increments extra_subflows after __mptcp_subflow_connect()
succeeds, but __mptcp_subflow_connect() calls mptcp_pm_close_subflow()
on failure to roll back the pre-increment done by the kernel PM's fill_*()
helpers. Because the userspace PM hasn't incremented yet at that point,
this decrement is spurious and causes extra_subflows to underflow.

Fix it by aligning the userspace PM with the kernel PM: increment
extra_subflows before calling __mptcp_subflow_connect(), so the existing
error path in subflow.c correctly rolls it back on failure. Also simplify
the error handling by taking pm.lock only when needed for cleanup.

Fixes: 77e4b94a3de6 ("mptcp: update userspace pm infos")
Cc: stable@vger.kernel.org
Signed-off-by: Tao Cui 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-5-856831229976@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

9p: avoid putting oldfid in p9_client_walk() error path

2026-07-04T11:41:32+00:00

commit 1a3860d46e3eb47dbd60339783cdad7904486b9f upstream.

When p9_client_walk() is called with clone set to false, fid aliases
oldfid. If the walk subsequently fails after the request has been sent,
the error path jumps to clunk_fid, which currently calls p9_fid_put(fid)
unconditionally.

This drops a reference to oldfid even though ownership of oldfid remains
with the caller. If this is the last reference, oldfid can be clunked and
destroyed while the caller still expects it to be valid. A later use or
put of oldfid can then trigger a use-after-free or refcount underflow.

Fix this by only putting fid in the clunk_fid error path when it does not
alias oldfid, matching the existing guard in the error path below.

This can be triggered when a multi-component walk is split into multiple
p9_client_walk() calls and a later non-cloning walk fails. A reproducer
and refcount warning logs are available on request.

Fixes: b48dbb998d70 ("9p fid refcount: add p9_fid_get/put wrappers")
Cc: stable@vger.kernel.org
Reported-by: Yuxiang Yang 
Reported-by: Ao Wang 
Reported-by: Xuewei Feng 
Reported-by: Qi Li 
Reported-by: Ke Xu 
Assisted-by: GLM 5.1
Signed-off-by: Yizhou Zhao 
Message-ID: <20260528053918.53550-1-zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Dominique Martinet 
Signed-off-by: Greg Kroah-Hartman

tipc: fix slab-use-after-free Read in tipc_aead_decrypt_done

2026-07-04T11:41:32+00:00

commit bda3348872a2ef0d19f2df6aa8cb5025adce2f20 upstream.

tipc_aead_decrypt() goes straight from tipc_bearer_hold(b) to
crypto_aead_decrypt(req) without taking a reference on the netns, unlike
the encrypt path. When crypto_aead_decrypt() is offloaded asynchronously
(e.g. the SIMD aead wrapper queuing to cryptd), the cryptd worker runs
tipc_aead_decrypt_done() later. If the bearer's netns is torn down in the
meantime, cleanup_net() -> tipc_exit_net() -> tipc_crypto_stop() frees the
per-netns tipc_crypto, and the completion then reads it:
tipc_aead_decrypt_done() dereferences aead->crypto->stats and
aead->crypto->net, and tipc_crypto_rcv_complete() dereferences
aead->crypto->aead[] and the node table -- reading freed memory.

Decoded KASAN splat (v7.1-rc7, CONFIG_KASAN_INLINE + TIPC + TIPC_CRYPTO):

  BUG: KASAN: slab-use-after-free in tipc_aead_decrypt_done (net/tipc/crypto.c:999)
  Read of size 8 at addr ffff8881056258a8 by task kworker/u16:2/51
  Workqueue: events_unbound
  Call Trace:
   tipc_aead_decrypt_done (net/tipc/crypto.c:999)
   process_one_work (kernel/workqueue.c:3314)
   worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
   kthread (kernel/kthread.c:436)
   ret_from_fork (arch/x86/kernel/process.c:158)
   ret_from_fork_asm (arch/x86/entry/entry_64.S:245)

  Allocated by task 169:
   __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)
   tipc_crypto_start (net/tipc/crypto.c:1502)
   tipc_init_net (net/tipc/core.c:72)
   ops_init (net/core/net_namespace.c:137)
   setup_net (net/core/net_namespace.c:446)
   copy_net_ns (net/core/net_namespace.c:579)
   create_new_namespaces (kernel/nsproxy.c:132)
   __x64_sys_unshare (kernel/fork.c:3316)
   do_syscall_64 (arch/x86/entry/syscall_64.c:63)
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)

  Freed by task 8:
   kfree (mm/slub.c:6566)
   tipc_exit_net (net/tipc/core.c:119)
   cleanup_net (net/core/net_namespace.c:704)
   process_one_work (kernel/workqueue.c:3314)
   kthread (kernel/kthread.c:436)

This is the same class of bug that commit e279024617134 ("net/tipc: fix
slab-use-after-free Read in tipc_aead_encrypt_done") fixed for the encrypt
side. The encrypt path takes maybe_get_net(aead->crypto->net) before
crypto_aead_encrypt() and drops it with put_net() on the synchronous
return paths and in tipc_aead_encrypt_done(); the -EINPROGRESS/-EBUSY
return keeps the reference for the async callback to release. The decrypt
path was left without the equivalent guard.

Mirror the encrypt-side fix on the decrypt path: take a net reference
before crypto_aead_decrypt() (failing with -ENODEV and the matching
bearer put if it cannot be acquired), keep it across the
-EINPROGRESS/-EBUSY async return, and drop it with put_net() on the
synchronous success/error return and at the end of
tipc_aead_decrypt_done().

Reproduced under KASAN on v7.1-rc7: a UDP bearer with a cluster key is
flooded with crafted encrypted frames from an unknown peer (driving the
cluster-key decrypt path) while the bearer's netns is repeatedly torn
down. The completion must run asynchronously to outlive
tipc_crypto_stop(); on x86 the stock aesni gcm(aes) now decrypts
synchronously, so the async path was exercised via cryptd offload. The
unguarded aead->crypto dereference in tipc_aead_decrypt_done() is the
unpatched upstream path; tipc_aead_decrypt() still lacks
maybe_get_net(aead->crypto->net), so the completion can outlive the free
on any config where crypto_aead_decrypt() goes async.

Found by 0sec automated security-research tooling (https://0sec.ai).

Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication")
Cc: stable@vger.kernel.org
Signed-off-by: Doruk Tan Ozturk 
Reviewed-by: Alexander Lobakin 
Reviewed-by: Tung Nguyen 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20260617075818.37431-1-doruk@0sec.ai
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: skmsg: preserve sg.copy across SG transforms

2026-07-04T11:41:31+00:00

commit 406e8a651a7b854c41fecd5117bb282b3a6c2c6b upstream.

The sk_msg sg.copy bitmap is part of the scatterlist entry ownership
state. A set bit tells sk_msg_compute_data_pointers() not to expose the
entry through writable BPF ctx->data. This protects entries backed by
pages that are not private to the sk_msg, such as splice-backed file
page-cache pages.

Several sk_msg transform paths move, copy, split, or compact
msg->sg.data[] entries without moving the matching sg.copy bit. This can
make an externally backed entry arrive at a new slot with a clear copy
bit. A later SK_MSG verdict can then expose sg_virt(sge) as writable
ctx->data and BPF stores can modify the original page cache.

Keep sg.copy synchronized with sg.data[] whenever entries are
transferred, shifted, split, or copied into a new sk_msg. Clear the bit
when an entry is replaced by a newly allocated private page or freed.
This covers the BPF pull/push/pop helpers, sk_msg_shift_left/right(),
sk_msg_xfer(), and tls_split_open_record(), including the partial tail
entry created during TLS open-record splitting.

Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling")
Cc: stable@vger.kernel.org
Reported-by: Yiming Qian 
Reported-by: Keenan Dong 
Signed-off-by: Yiming Qian 
Link: https://patch.msgid.link/20260610062137.49075-1-yimingqian591@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

mac802154: llsec: add skb_cow_data() before in-place crypto

2026-07-04T11:41:31+00:00

commit 84a04eb5b210643bd67aab81ff805d32f62aa865 upstream.

llsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),
llsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform
in-place cryptographic transformations on skb data.  They build a
scatterlist with sg_init_one() pointing into the skb's linear data area
and then pass the same scatterlist as both src and dst to the crypto API
(e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt).

On the RX path, __ieee802154_rx_handle_packet() clones the received skb
before handing it to each subscriber via ieee802154_subif_frame().  The
cloned skb shares the same underlying data buffer via reference
counting.  When llsec_do_decrypt() subsequently modifies this shared
buffer in place, it corrupts data that other clones -- potentially
belonging to other sockets or subsystems -- still reference.

On the TX path, similar data sharing can occur when an skb's head has
been cloned (skb_cloned() returns true).

The fix is to call skb_cow_data() before performing any in-place crypto
operation.  skb_cow_data() ensures that the skb's data area is not
shared: if the skb head is cloned or the data spans multiple fragments,
it copies the data into a private buffer that can be safely modified in
place.  This is the same pattern used by:

  - ESP (net/ipv4/esp4.c, net/ipv6/esp6.c)
  - MACsec (drivers/net/macsec.c)
  - WireGuard (drivers/net/wireguard/receive.c)
  - TIPC (net/tipc/crypto.c)

Without this guard, in-place crypto on shared skb data leads to:
  - Silent data corruption of other skb clones
  - Use-after-free when the crypto API scatterwalk writes through a
    page that has already been freed by another clone's kfree_skb()
  - Kernel crashes under concurrent 802.15.4 traffic with security
    enabled (KASAN/KMSAN reports slab-use-after-free)

Found by 0sec (https://0sec.ai) using automated source analysis.

Fixes: 4c14a2fb5d14 ("mac802154: add llsec decryption method")
Fixes: 03556e4d0dbb ("mac802154: add llsec encryption method")
Cc: stable@vger.kernel.org
Reported-by: Doruk Tan Ozturk 
Closes: https://lore.kernel.org/linux-wpan/20260525161806.96158-1-doruk@0sec.ai/
Reviewed-by: Alexander Lobakin 
Signed-off-by: Doruk Tan Ozturk 
Closes: 
Link: https://lore.kernel.org/20260526183726.56100-1-doruk@0sec.ai
Signed-off-by: Stefan Schmidt 
Signed-off-by: Greg Kroah-Hartman