linux-stable.git/net/core, branch v7.1.6

net: gro: fix double aggregation of flush-marked skbs

2026-08-03T09:25:58+00:00

commit e751256486d0ded20f5a9f9863467f1dce65142f upstream.

Commit 0ab03f353d36 ("net-gro: Fix GRO flush when receiving a GSO
packet.") added a flush check to skb_gro_receive(), but
skb_gro_receive_list() lacks the same validation.

As a result, packets marked with NAPI_GRO_CB(skb)->flush may still be
re-aggregated.

This allows already-GRO'd packets with existing frag_list to be
re-aggregated into a new GRO session, corrupting the frag_list chain
structure. When skb_segment() attempts to unpack these malformed packets,
it encounters invalid state and triggers a kernel panic.

Scenario (Tethering/Device forwarding):
  1. Driver: Generated aggregated packet P1 via LRO with frag_list
  2. Dev A: Receives aggregated fraglist packet and flush flag set
  3. Dev A: Re-enters GRO, skb_gro_receive_list() is called
  4. Missing flush check allows re-aggregation despite flush flag
  5. Frag_list chain becomes corrupted (loops or dangling refs)
  6. Dev B: TX path calls skb_segment(), crashes on corrupted frag_list

Root cause in skb_segment():
  The check at line ~4891:
    if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) &&
        (skb_headlen(list_skb) == len || sg)) {

  When frag_list is corrupted by double aggregation, when list_skb is
  a NULL pointer from skb->next, skb_headlen(list_skb) dereference
  NULL/corrupted pointers occurs.

Call Trace:
 skb_headlen(NULL skb)
 skb_segment
 tcp_gso_segment
 tcp4_gso_segment
 inet_gso_segment
 skb_mac_gso_segment
 __skb_gso_segment
 skb_gso_segment
 validate_xmit_skb
 validate_xmit_skb_list
 sch_direct_xmit
 qdisc_restart
 __qdisc_run
 qdisc_run
 net_tx_action

Fix: Add NAPI_GRO_CB(skb)->flush validation to the early-return check in
skb_gro_receive_list(), matching the defensive programming pattern of
skb_gro_receive().

Fixes: 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
Cc: stable@vger.kernel.org
Signed-off-by: Shiming Cheng 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20260709014704.3625-1-shiming.cheng@mediatek.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

drop_monitor: perform u64_stats updates under IRQ-disabled section

2026-08-03T09:25:38+00:00

[ Upstream commit fd098a23bf8fda7eae48db9b06e7c34fc4d228fa ]

In net_dm_packet_trace_kfree_skb_hit() and net_dm_hw_trap_packet_probe(),
u64_stats_update_begin() / u64_stats_inc() / u64_stats_update_end() were
called after spin_unlock_irqrestore(&...drop_queue.lock, flags), when local
IRQs had already been re-enabled.

Tracepoint probes can execute in IRQ or softirq context. On 32-bit
architectures, u64_stats_update_begin() disables preemption but not interrupts,
relying on seqcount writes. If a nested interrupt occurs on the same CPU during
the 64-bit stats update, the reentrant seqcount update can corrupt the
seqcount state or stats value.

Fix this by performing the 64-bit per-CPU stats update before releasing
drop_queue.lock via spin_unlock_irqrestore(), ensuring local interrupts remain
disabled during the u64_stats update.

Fixes: e9feb58020f9 ("drop_monitor: Expose tail drop counter")
Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for hardware drops")
Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20260722141743.3266924-3-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

drop_monitor: fix size calculations for 64-bit attributes

2026-08-03T09:25:38+00:00

[ Upstream commit 7089f7ab99c89f443c92d8fcc585e63f2727f0b3 ]

net_dm_packet_report_fill() and net_dm_hw_packet_report_fill() use
nla_put_u64_64bit() to append 64-bit attributes (NET_DM_ATTR_PC and
NET_DM_ATTR_TIMESTAMP).

On 32-bit architectures without CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
nla_put_u64_64bit() may append a 4-byte NET_DM_ATTR_PAD attribute for
64-bit alignment.

However, net_dm_packet_report_size() and net_dm_hw_packet_report_size()
used nla_total_size(sizeof(u64)) instead of nla_total_size_64bit(sizeof(u64)),
budgeting 12 bytes instead of up to 16 bytes.

This under-estimation of SKB size can lead to an skb_over_panic() when
__nla_reserve() or skb_put() is subsequently called.

Fix this by using nla_total_size_64bit(sizeof(u64)) in both size calculations.

Fixes: ca30707dee2b ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for hardware drops")
Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20260722141743.3266924-2-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD

2026-08-03T09:25:38+00:00

[ Upstream commit 5e9c8baee0329fbefe7c67aea945e2a07f15e98b ]

net_dm_packet_report_fill() and net_dm_hw_packet_report_fill() open code
the NET_DM_ATTR_PAYLOAD attribute to avoid zeroing the packet payload
before overwriting it with skb_copy_bits().

skb_put() reserves nla_total_size(payload_len), i.e. the header plus the
NLA_ALIGN() padding, but only payload_len bytes are copied in. When
payload_len is not a multiple of 4 the 1-3 padding bytes are never
initialized and are leaked to user space inside the netlink message.

KMSAN confirms the leak for the software path when the packet payload
length is not 4-byte aligned:

  BUG: KMSAN: kernel-infoleak in _copy_to_iter
   _copy_to_iter
   __skb_datagram_iter
   skb_copy_datagram_iter
   netlink_recvmsg
   sock_recvmsg
   __sys_recvfrom
  Uninit was created at:
   kmem_cache_alloc_node_noprof
   __alloc_skb
   net_dm_packet_work
  Bytes 173-175 of 176 are uninitialized

Use __nla_reserve(), which sets up the attribute header and zeroes the
padding, instead of open coding the attribute construction.

Fixes: ca30707dee2b ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for hardware drops")
Suggested-by: Eric Dumazet 
Signed-off-by: Yehyeong Lee 
Link: https://patch.msgid.link/20260722122817.5548-1-yhlee@isslab.korea.ac.kr
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: Call net_enable_timestamp() before failure in sk_clone().

2026-08-03T09:25:32+00:00

[ Upstream commit d50557779257a00162411e3048d82971ff1f644c ]

When sk_clone() fails, sk_destruct() is called for the new socket.

If the parent socket has SK_FLAGS_TIMESTAMP in sk->sk_flags,
net_disable_timestamp() is called for the child socket even though
net_enable_timestamp() is not called for it.

Let's call net_enable_timestamp() before any failure path in
sk_clone().

Fixes: 704da560c0a0 ("tcp: update the netstamp_needed counter when cloning sockets")
Reported-by: Sashiko 
Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Jason Xing 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20260709183315.965751-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

soreuseport: Clear sk_reuseport_cb before failure in sk_clone().

2026-08-03T09:25:32+00:00

[ Upstream commit 98da8ce87dd561f08fbe44f75865edc5d9b2ba5f ]

When sk_clone() fails, sk_destruct() is called for the new socket.

If the parent socket has sk->sk_reuseport_cb, the child will call
reuseport_detach_sock() for the reuseport group.

Let's clear sk->sk_reuseport_cb before any failure path in sk_clone().

Note that this was not a problem before the cited commit because
reuseport_detach_sock() did nothing if the socket was not found in
the reuseport array.

Fixes: 5dc4c4b7d4e8 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY")
Reported-by: Sashiko 
Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Jason Xing 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20260709183315.965751-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

bpf: Reject redirect helpers without a bpf_net_context

2026-08-03T09:25:30+00:00

[ Upstream commit 3f4920d165b29052255527d8ae7619e7ec132ece ]

The bpf_redirect*() helpers and skb_do_redirect() obtain the per-task
bpf_redirect_info via bpf_net_ctx_get_ri(), which dereferences the
current->bpf_net_context unconditionally. That context is established
on the paths that run tc BPF such as sch_handle_{ingress,egress}(),
*except* for the case where {cls,act}_bpf was attached to a proper
qdisc. A program running from there reaches the NULL deref in two ways:

* It calls bpf_redirect() directly, which dereferences the context at
  the top of the helper:

     tc qdisc add dev eth0 root handle 1: red limit 1MB min 10KB max 20KB \
        avpkt 1000 burst 100 qevent early_drop block 10
     tc filter add block 10 pref 1 bpf obj redirect.o

* It simply returns TC_ACT_REDIRECT without helper call: tcf_qevent_handle()
  then dispatches to skb_do_redirect(), which dereferences the context

Rather than extending bpf_net_context management into the qdisc path,
make the redirect helpers refuse to operate when no context exists, and
have tcf_qevent_handle() drop a TC_ACT_REDIRECT verdict instead of
calling skb_do_redirect(). Previous behaviour was a crash, so nothing
regresses by not supporting it.

Fixes: 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.")
Fixes: 3625750f05ec ("net: sched: Introduce helpers for qevent blocks")
Signed-off-by: Daniel Borkmann 
Reviewed-by: Sebastian Andrzej Siewior 
Link: https://patch.msgid.link/20260706185609.330006-2-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

bpf, sockmap: Reject unhashed UDP sockets on sockmap update

2026-08-03T09:25:22+00:00

[ Upstream commit 66efd3368ae10d05e08fbe6425b50fdec7186ac7 ]

UDP sockets get SOCK_RCU_FREE set when (auto-)bound. This means
sk_is_refcounted(unbound) = true, while sk_is_refcounted(bound) = false.

Because sockmap accepts unbound UDP sockets, a BPF program can increment a
socket's refcount via lookup. If the socket is subsequently bound, the
transition from unbound to bound causes bpf_sk_release() to skip the
decrement of the refcount, causing a memory leak.

unreferenced object 0xffff88810bc2eb40 (size 1984):
  comm "test_progs", pid 2451, jiffies 4295320596
  hex dump (first 32 bytes):
    7f 00 00 01 7f 00 00 01 d2 04 1b b7 04 d2 00 00  ................
    02 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............
  backtrace (crc bdee079d):
    kmem_cache_alloc_noprof+0x557/0x660
    sk_prot_alloc+0x69/0x240
    sk_alloc+0x30/0x460
    inet_create+0x2ce/0xf80
    __sock_create+0x25b/0x5c0
    __sys_socket+0x119/0x1d0
    __x64_sys_socket+0x72/0xd0
    do_syscall_64+0xa1/0x5f0
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

Instead of special-casing for refcounted sockets, reject unhashed UDP
sockets during sockmap updates, as there is no benefit to supporting those.
This effectively reverts the commit under Fixes, with two exceptions:

1. sock_map_sk_state_allowed() maintains a fall-through `return true`.
2. In the spirit of commit b8b8315e39ff ("bpf, sockmap: Remove unhash
   handler for BPF sockmap usage"), the proto::unhash BPF handler is not
   reintroduced.

Historical note: this issue is related to commit 67312adc96b5 ("bpf: reject
unhashed sockets in bpf_sk_assign").

Fixes: 0c48eefae712 ("sock_map: Lift socket state restriction for datagram sockets")
Suggested-by: Kuniyuki Iwashima 
Signed-off-by: Michal Luczaj 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: Jakub Sitnicki 
Reviewed-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20260707-sockmap-lookup-udp-leak-v4-2-f878346f27ab@rbox.co
Signed-off-by: Kumar Kartikeya Dwivedi 
Signed-off-by: Sasha Levin

bpf: Fix UAF in sock clone early bailouts

2026-08-03T09:25:20+00:00

[ Upstream commit 7cbd0c4cebe4c9f678d15e6b9ba975e1155a107f ]

Similar to recent commit 9b51a6155d14 ("bpf,fork: wipe ->bpf_storage
before bailouts that access it"), sk_clone() performs an initial
shallow copy of the socket field ->sk_bpf_storage via sock_copy()
for the cloned socket newsk.

If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior
to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points
to the parent socket's BPF local storage. When newsk is subsequently
freed via sk_free(), the deallocation path (__sk_destruct() ->
bpf_sk_storage_free()) destroys the parent socket's BPF local storage,
leading to a use-after-free (UAF) on the parent socket.

Fix this by resetting newsk->sk_bpf_storage to NULL immediately after
sock_copy() in sk_clone(), and remove the now redundant initialization
from bpf_sk_storage_clone().

Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage")
Fixes: f12dd75959b0 ("bpf: net: Set sk_bpf_storage back to NULL for cloned sk")
Signed-off-by: Matt Bobrowski 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Kuniyuki Iwashima 
Acked-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20260709025316.999913-1-mattbobrowski@google.com
Signed-off-by: Sasha Levin

xfrm: propagate -EINPROGRESS from validate_xmit_xfrm()

2026-08-03T09:25:16+00:00

[ Upstream commit 6860b467f569f732b11cbc588ae7e195e90e7e23 ]

validate_xmit_xfrm() returns NULL both when a packet is dropped and
when it is stolen by async crypto (-EINPROGRESS from ->xmit()).
Callers cannot distinguish the two cases.

f53c723902d1 ("net: Add asynchronous callbacks for xfrm on layer 2.")
changed the semantics of a NULL return from "dropped" to "stolen or
dropped", but __dev_queue_xmit() was not updated.  On virtual/bridge
interfaces (noqueue qdisc) __dev_queue_xmit() initialises rc=-ENOMEM
and jumps to out: when skb is NULL, returning -ENOMEM to the caller
even though the packet will be delivered correctly via xfrm_dev_resume().

Return ERR_PTR(-EINPROGRESS) from validate_xmit_xfrm() for the async
case so callers can tell it apart from a real drop.  Update
__dev_queue_xmit() to handle ERR_PTR(-EINPROGRESS) from
validate_xmit_skb() correctly.  Update validate_xmit_skb_list() to
use IS_ERR_OR_NULL() so that ERR_PTR(-EINPROGRESS) is not mistakenly
added to the transmitted list.

Fixes: f53c723902d1 ("net: Add asynchronous callbacks for xfrm on layer 2.")
Suggested-by: Sabrina Dubroca 
Signed-off-by: Petr Wozniak 
Signed-off-by: Steffen Klassert 
Signed-off-by: Sasha Levin