linux-stable.git/net/core, branch v7.0.7

netpoll: pass buffer size to egress_dev() to avoid MAC truncation

2026-05-14T13:31:09+00:00

commit 76b93a8107574006b25495664304ea9237494d70 upstream.

egress_dev() formats np->dev_mac via snprintf() but receives buf as
a bare char *, so it cannot derive the buffer size from the pointer. The
size argument was hardcoded to MAC_ADDR_STR_LEN (3 * ETH_ALEN - 1 = 17),
which is silly wrong in two ways:

 1) misleading kernel log output on the MAC-selected target path
    (np->dev_name[0] == '\0'); for example "aa:bb:cc:dd:ee:ff doesn't
    exist, aborting" was logged as "aa:bb:cc:dd:ee:f doesn't exist,
    aborting".

 2) the second argument of snprintf is the size of the buffer, not the
    size of what you want to write.

Add a bufsz parameter to egress_dev() and pass sizeof(buf) from each
caller, matching the standard snprintf() idiom and removing the
hardcoded size from the helper.

Every caller already declares "char buf[MAC_ADDR_STR_LEN + 1]" so the
formatted MAC continues to fit.

Tested by booting with
  netconsole=6665@/aa:bb:cc:dd:ee:ff,6666@10.0.0.1/00:11:22:33:44:55
on a kernel without a matching device. Pre-fix dmesg shows
"aa:bb:cc:dd:ee:f doesn't exist, aborting"; post-fix shows the full
"aa:bb:cc:dd:ee:ff doesn't exist, aborting".

Fixes: f8a10bed32f5 ("netconsole: allow selection of egress interface via MAC address")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao 
Link: https://patch.msgid.link/20260501-netpoll_snprintf_fix-v1-1-84b0566e6597@debian.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo

2026-05-14T13:31:07+00:00

commit 4b9e327991815e128ad3af75c3a04630a63ce3e0 upstream.

rtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack
without initialisation:

	struct ifla_vf_broadcast vf_broadcast;

The struct contains a single fixed 32-byte field:

	/* include/uapi/linux/if_link.h */
	struct ifla_vf_broadcast {
		__u8 broadcast[32];
	};

The function then copies dev->broadcast into it using dev->addr_len
as the length:

	memcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len);

On Ethernet devices (the overwhelming majority of SR-IOV NICs)
dev->addr_len is 6, so only the first 6 bytes of broadcast[] are
written. The remaining 26 bytes retain whatever was previously on
the kernel stack. The full struct is then handed to userspace via:

	nla_put(skb, IFLA_VF_BROADCAST,
		sizeof(vf_broadcast), &vf_broadcast)

leaking up to 26 bytes of uninitialised kernel stack per VF per
RTM_GETLINK request, repeatable.

The other vf_* structs in the same function are explicitly zeroed
for exactly this reason - see the memset() calls for ivi,
vf_vlan_info, node_guid and port_guid a few lines above.
vf_broadcast was simply missed when it was added.

Reachability: any unprivileged local process can open AF_NETLINK /
NETLINK_ROUTE without capabilities and send RTM_GETLINK with an
IFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks
each VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per
VF per request. Stack residue at this call site can include return
addresses and transient sensitive data; KASAN with stack
instrumentation, or KMSAN, will flag the nla_put() when reproduced.

Zero the on-stack struct before the partial memcpy, matching the
existing pattern used for the other vf_* structs in the same
function.

Fixes: 75345f888f70 ("ipoib: show VF broadcast address")
Cc: stable@vger.kernel.org
Signed-off-by: Kai Zen 
Link: https://patch.msgid.link/3c506e8f936e52b57620269b55c348af05d413a2.1777557228.git.kai.aizen.dev@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

flow_dissector: do not dissect PPPoE PFC frames

2026-05-14T13:31:03+00:00

[ Upstream commit d6c19b31a3c1d519fabdcf0aa239e6b6109b9473 ]

RFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT
RECOMMENDED for PPPoE. In practice, pppd does not support negotiating
PFC for PPPoE sessions, and the flow dissector driver has assumed an
uncompressed frame until the blamed commit.

During the review process of that commit [1], support for PFC is
suggested. However, having a compressed (1-byte) protocol field means
the subsequent PPP payload is shifted by one byte, causing 4-byte
misalignment for the network header and an unaligned access exception
on some architectures.

The exception can be reproduced by sending a PPPoE PFC frame to an
ethernet interface of a MIPS board, with RPS enabled, even if no PPPoE
session is active on that interface:

$ 0   : 00000000 80c40000 00000000 85144817
$ 4   : 00000008 00000100 80a75758 81dc9bb8
$ 8   : 00000010 8087ae2c 0000003d 00000000
$12   : 000000e0 00000039 00000000 00000000
$16   : 85043240 80a75758 81dc9bb8 00006488
$20   : 0000002f 00000007 85144810 80a70000
$24   : 81d1bda0 00000000
$28   : 81dc8000 81dc9aa8 00000000 805ead08
Hi    : 00009d51
Lo    : 2163358a
epc   : 805e91f0 __skb_flow_dissect+0x1b0/0x1b50
ra    : 805ead08 __skb_get_hash_net+0x74/0x12c
Status: 11000403        KERNEL EXL IE
Cause : 40800010 (ExcCode 04)
BadVA : 85144817
PrId  : 0001992f (MIPS 1004Kc)
Call Trace:
[<805e91f0>] __skb_flow_dissect+0x1b0/0x1b50
[<805ead08>] __skb_get_hash_net+0x74/0x12c
[<805ef330>] get_rps_cpu+0x1b8/0x3fc
[<805fca70>] netif_receive_skb_list_internal+0x324/0x364
[<805fd120>] napi_complete_done+0x68/0x2a4
[<8058de5c>] mtk_napi_rx+0x228/0xfec
[<805fd398>] __napi_poll+0x3c/0x1c4
[<805fd754>] napi_threaded_poll_loop+0x234/0x29c
[<805fd848>] napi_threaded_poll+0x8c/0xb0
[<80053544>] kthread+0x104/0x12c
[<80002bd8>] ret_from_kernel_thread+0x14/0x1c

Code: 02d51821  1060045b  00000000 <8c640000> 3084000f  2c820005  144001a2  00042080  8e220000

To reduce the attack surface and maintain performance, do not process
PPPoE PFC frames.

[1] https://lore.kernel.org/r/20220630231016.GA392@debian.home
Fixes: 46126db9c861 ("flow_dissector: Add PPPoE dissectors")
Signed-off-by: Qingfang Deng 
Link: https://patch.msgid.link/20260415022456.141758-1-qingfang.deng@linux.dev
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

Merge tag 'vfs-7.0-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-04-10T15:40:49+00:00

Pull vfs fixes from Christian Brauner:
 "The kernfs rbtree is keyed by (hash, ns, name) where the hash
  is seeded with the raw namespace pointer via init_name_hash(ns).

  The resulting hash values are exposed to userspace through
  readdir seek positions, and the pointer-based ordering in
  kernfs_name_compare() is observable through entry order.

  Switch from raw pointers to ns_common::ns_id for both hashing
  and comparison.

  A preparatory commit first replaces all const void * namespace
  parameters with const struct ns_common * throughout kernfs, sysfs,
  and kobject so the code can access ns->ns_id. Also compare the
  ns_id when hashes match in the rbtree to handle crafted collisions.

  Also fix eventpoll RCU grace period issue and a cachefiles refcount
  problem"

* tag 'vfs-7.0-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  kernfs: make directory seek namespace-aware
  kernfs: use namespace id instead of pointer for hashing and comparison
  kernfs: pass struct ns_common instead of const void * for namespace tags
  eventpoll: defer struct eventpoll free to RCU grace period
  cachefiles: fix incorrect dentry refcount in cachefiles_cull()

Merge tag 'net-7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-04-09T15:39:25+00:00

Pull networking fixes from Paolo Abeni:
 "Including fixes from netfilter, IPsec and wireless. This is again
  considerably bigger than the old average. No known outstanding
  regressions.

  Current release - regressions:

   - net: increase IP_TUNNEL_RECURSION_LIMIT to 5

   - eth: ice: fix PTP timestamping broken by SyncE code on E825C

  Current release - new code bugs:

   - eth: stmmac: dwmac-motorcomm: fix eFUSE MAC address read failure

  Previous releases - regressions:

   - core: fix cross-cache free of KFENCE-allocated skb head

   - sched: act_csum: validate nested VLAN headers

   - rxrpc: fix call removal to use RCU safe deletion

   - xfrm:
      - wait for RCU readers during policy netns exit
      - fix refcount leak in xfrm_migrate_policy_find

   - wifi: rt2x00usb: fix devres lifetime

   - mptcp: fix slab-use-after-free in __inet_lookup_established

   - ipvs: fix NULL deref in ip_vs_add_service error path

   - eth:
      - airoha: fix memory leak in airoha_qdma_rx_process()
      - lan966x: fix use-after-free and leak in lan966x_fdma_reload()

  Previous releases - always broken:

   - ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data()

   - ipv4: nexthop: avoid duplicate NHA_HW_STATS_ENABLE on nexthop group
     dump

   - bridge: guard local VLAN-0 FDB helpers against NULL vlan group

   - xsk: tailroom reservation and MTU validation

   - rxrpc:
      - fix to request an ack if window is limited
      - fix RESPONSE authenticator parser OOB read

   - netfilter: nft_ct: fix use-after-free in timeout object destroy

   - batman-adv: hold claim backbone gateways by reference

   - eth:
      - stmmac: fix PTP ref clock for Tegra234
      - idpf: fix PREEMPT_RT raw/bh spinlock nesting for async VC handling
      - ipa: fix GENERIC_CMD register field masks for IPA v5.0+"

* tag 'net-7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (104 commits)
  net: lan966x: fix use-after-free and leak in lan966x_fdma_reload()
  net: lan966x: fix page pool leak in error paths
  net: lan966x: fix page_pool error handling in lan966x_fdma_rx_alloc_page_pool()
  nfc: pn533: allocate rx skb before consuming bytes
  l2tp: Drop large packets with UDP encap
  net: ipa: fix event ring index not programmed for IPA v5.0+
  net: ipa: fix GENERIC_CMD register field masks for IPA v5.0+
  MAINTAINERS: Add Prashanth as additional maintainer for amd-xgbe driver
  devlink: Fix incorrect skb socket family dumping
  af_unix: read UNIX_DIAG_VFS data under unix_state_lock
  Revert "mptcp: add needs_id for netlink appending addr"
  mptcp: fix slab-use-after-free in __inet_lookup_established
  net: txgbe: leave space for null terminators on property_entry
  net: ioam6: fix OOB and missing lock
  rxrpc: proc: size address buffers for %pISpc output
  rxrpc: only handle RESPONSE during service challenge
  rxrpc: Fix buffer overread in rxgk_do_verify_authenticator()
  rxrpc: Fix leak of rxgk context in rxgk_verify_response()
  rxrpc: Fix integer overflow in rxgk_verify_response()
  rxrpc: Fix missing error checks for rxkad encryption/decryption failure
  ...

kernfs: pass struct ns_common instead of const void * for namespace tags

2026-04-09T12:36:52+00:00

kernfs has historically used const void * to pass around namespace tags
used for directory-level namespace filtering. The only current user of
this is sysfs network namespace tagging where struct net pointers are
cast to void *.

Replace all const void * namespace parameters with const struct
ns_common * throughout the kernfs, sysfs, and kobject namespace layers.
This includes the kobj_ns_type_operations callbacks, kobject_namespace(),
and all sysfs/kernfs APIs that accept or return namespace tags.

Passing struct ns_common is needed because various codepaths require
access to the underlying namespace. A struct ns_common can always be
converted back to the concrete namespace type (e.g., struct net) via
container_of() or to_ns_common() in the reverse direction.

This is a preparatory change for switching to ns_id-based directory
iteration to prevent a KASLR pointer leak through the current use of
raw namespace pointers as hash seeds and comparison keys.

Signed-off-by: Christian Brauner

net: avoid nul-deref trying to bind mp to incapable device

2026-04-08T01:57:56+00:00

Sashiko points out that we use qops in __net_mp_open_rxq()
but never validate they are null. This was introduced when
check was moved from netdev_rx_queue_restart().

Look at ops directly instead of the locking config.
qops imply netdev_need_ops_lock(). We used netdev_need_ops_lock()
initially to signify that the real_num_rx_queues check below
is safe without rtnl_lock, but I'm not sure if this is actually
clear to most people, anyway.

Fixes: da7772a2b4ad ("net: move mp->rx_page_size validation to __net_mp_open_rxq()")
Acked-by: Daniel Borkmann 
Reviewed-by: Mina Almasry 
Link: https://patch.msgid.link/20260404001938.2425670-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: skb: fix cross-cache free of KFENCE-allocated skb head

2026-04-07T01:46:53+00:00

SKB_SMALL_HEAD_CACHE_SIZE is intentionally set to a non-power-of-2
value (e.g. 704 on x86_64) to avoid collisions with generic kmalloc
bucket sizes. This ensures that skb_kfree_head() can reliably use
skb_end_offset to distinguish skb heads allocated from
skb_small_head_cache vs. generic kmalloc caches.

However, when KFENCE is enabled, kfence_ksize() returns the exact
requested allocation size instead of the slab bucket size. If a caller
(e.g. bpf_test_init) allocates skb head data via kzalloc() and the
requested size happens to equal SKB_SMALL_HEAD_CACHE_SIZE, then
slab_build_skb() -> ksize() returns that exact value. After subtracting
skb_shared_info overhead, skb_end_offset ends up matching
SKB_SMALL_HEAD_HEADROOM, causing skb_kfree_head() to incorrectly free
the object to skb_small_head_cache instead of back to the original
kmalloc cache, resulting in a slab cross-cache free:

  kmem_cache_free(skbuff_small_head): Wrong slab cache. Expected
  skbuff_small_head but got kmalloc-1k

Fix this by always calling kfree(head) in skb_kfree_head(). This keeps
the free path generic and avoids allocator-specific misclassification
for KFENCE objects.

Fixes: bf9f1baa279f ("net: add dedicated kmem_cache for typical/small skb->head")
Reported-by: Antonius 
Closes: https://lore.kernel.org/netdev/CAK8a0jxC5L5N7hq-DT2_NhUyjBxrPocoiDazzsBk4TGgT1r4-A@mail.gmail.com/
Signed-off-by: Jiayuan Chen 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20260403014517.142550-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski

rtnetlink: add missing netlink_ns_capable() check for peer netns

2026-04-03T22:07:18+00:00

rtnl_newlink() lacks a CAP_NET_ADMIN capability check on the peer
network namespace when creating paired devices (veth, vxcan,
netkit). This allows an unprivileged user with a user namespace
to create interfaces in arbitrary network namespaces, including
init_net.

Add a netlink_ns_capable() check for CAP_NET_ADMIN in the peer
namespace before allowing device creation to proceed.

Fixes: 81adee47dfb6 ("net: Support specifying the network namespace upon device creation.")
Signed-off-by: Nikolaos Gkarlis 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20260402181432.4126920-1-nickgarlis@gmail.com
Signed-off-by: Jakub Kicinski

Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2026-04-03T01:59:56+00:00

Pull bpf fixes from Alexei Starovoitov:

 - Fix register equivalence for pointers to packet (Alexei Starovoitov)

 - Fix incorrect pruning due to atomic fetch precision tracking (Daniel
   Borkmann)

 - Fix grace period wait for bpf_link-ed tracepoints (Kumar Kartikeya
   Dwivedi)

 - Fix use-after-free of sockmap's sk->sk_socket (Kuniyuki Iwashima)

 - Reject direct access to nullable PTR_TO_BUF pointers (Qi Tang)

 - Reject sleepable kprobe_multi programs at attach time (Varun R
   Mallya)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Add more precision tracking tests for atomics
  bpf: Fix incorrect pruning due to atomic fetch precision tracking
  bpf: Reject sleepable kprobe_multi programs at attach time
  bpf: reject direct access to nullable PTR_TO_BUF pointers
  bpf: sockmap: Fix use-after-free of sk->sk_socket in sk_psock_verdict_data_ready().
  bpf: Fix grace period wait for tracepoint bpf_link
  bpf: Fix regsafe() for pointers to packet