| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
slip: fix use-after-free in sl_sync()
slip_devs[] stores bare net_device pointers and takes no reference on
them. sl_sync() and sl_alloc() walk that table from slip_open() under
rtnl_lock(), while an entry is dropped by sl_free_netdev(), which
sl_setup() installs as dev->priv_destructor.
priv_destructor is called from netdev_run_todo(), which deliberately
runs with the RTNL semaphore released so that it can sleep while waiting
for the device refcount to drop:
/* Snapshot list, allow later requests */
list_replace_init(&net_todo_list, &list);
__rtnl_unlock();
...
if (dev->priv_destructor)
dev->priv_destructor(dev); /* slip_devs[i] = NULL */
if (dev->needs_free_netdev)
free_netdev(dev);
...
/* Free network device */
kobject_put(&dev->dev.kobj);
So rtnl_lock() does not serialise slip_open() against the teardown at
all. sl_sync() can load slip_devs[i] while the entry is still published
and dereference it after netdev_run_todo() has run the destructor and
released the device:
CPU0 (slip_open) CPU1 (slip_close)
unregister_netdev()
rtnl_unlock()
netdev_run_todo()
__rtnl_unlock()
rtnl_lock()
sl_sync()
dev = slip_devs[i]
priv_destructor(dev)
slip_devs[i] = NULL
kobject_put(&dev->dev.kobj)
/* dev is freed */
sl = netdev_priv(dev)
if (sl->tty || sl->leased) /* use-after-free */
BUG: KASAN: use-after-free in sl_sync drivers/net/slip/slip.c:730 [inline]
BUG: KASAN: use-after-free in slip_open+0xef4/0x1210 drivers/net/slip/slip.c:806
Read of size 1 at addr ffff8880712dac71 by task syz-executor.2/6506
CPU: 2 PID: 6506 Comm: syz-executor.2 Not tainted 6.1.134-syzkaller-00260-g0c8fc3469765 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
sl_sync drivers/net/slip/slip.c:730 [inline]
slip_open+0xef4/0x1210 drivers/net/slip/slip.c:806
tty_ldisc_open+0xa2/0x120 drivers/tty/tty_ldisc.c:433
tty_set_ldisc+0x324/0x720 drivers/tty/tty_ldisc.c:564
tiocsetd drivers/tty/tty_io.c:2428 [inline]
tty_ioctl+0x5f0/0x1530 drivers/tty/tty_io.c:2712
Allocated by task 6502:
alloc_netdev_mqs+0x98/0xfe0 net/core/dev.c:10719
sl_alloc drivers/net/slip/slip.c:756 [inline]
slip_open+0x36d/0x1210 drivers/net/slip/slip.c:817
tty_ldisc_open+0xa2/0x120 drivers/tty/tty_ldisc.c:433
tty_set_ldisc+0x324/0x720 drivers/tty/tty_ldisc.c:564
Freed by task 6497:
device_release+0xa2/0x240 drivers/base/core.c:2507
kobject_put+0x179/0x280 lib/kobject.c:729
netdev_run_todo+0x6c8/0xef0 net/core/dev.c:10509
slip_close+0x166/0x1c0 drivers/net/slip/slip.c:906
tty_ldisc_close+0x113/0x1a0 drivers/tty/tty_ldisc.c:456
tty_ldisc_kill+0x94/0x160 drivers/tty/tty_ldisc.c:614
tty_ldisc_release+0xe3/0x2b0 drivers/tty/tty_ldisc.c:782
tty_release+0xbcc/0xe70 drivers/tty/tty_io.c:1860
Commit e58c19124189 ("slip: Fix use-after-free Read in slip_open") fixed
a different source of stale entries - a device left in slip_devs[] after
slip_open() freed it on the registration error path - and does not
address this race, which is why the report survives it.
Drop the entry from ndo_uninit instead. unregister_netdevice() calls
ndo_uninit under RTNL, before the device is queued to netdev_run_todo(),
so an entry that sl_sync() can still see while holding RTNL belongs to a
device that cannot be freed until RTNL is dropped. sl_free_netdev()
stays only for the slip_open() error path, where register_netdevice()
may have failed before ndo_init and ndo_uninit is then not called
either. Both running for the same device is harmless: the
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix flow mask use-after-free on flow deletion
The commit in the Fixes tag below made so flow->mask free is scheduled
via RCU right after it is removed from the flow table. The pointer
stays in the flow structure and it can be accessible while in the same
RCU critical section. This is done to avoid requiring ovs_mutex for
the ovs_flow_free().
However, while removing the flow during processing of CMD_DEL, we do
not take RCU read lock before the removal, and ovs_flow_cmd_fill_info()
uses the flow->mask pointer afterwards. The RCU read lock is taken,
but it's already late at that point. The comment on that line
acknowledges that the lock is cosmetic and doesn't serve a real purpose.
This leads to use-after-free if the RCU grace period passes between
removal and the filling. It is a short race window, but it is there
and can lead to a real crash in case memory allocation for the info
takes a bit longer:
BUG: KASAN: slab-use-after-free in __ovs_nla_put_key
net/openvswitch/flow_netlink.c:1996
BUG: KASAN: slab-use-after-free in ovs_nla_put_key+0x2463/0x2e30
net/openvswitch/flow_netlink.c:2250
Read of size 4 at addr ffff88801ee89970 by task ovs_flow_del_ec/9487
Call Trace:
<TASK>
__ovs_nla_put_key net/openvswitch/flow_netlink.c:1996
ovs_nla_put_key+0x2463/0x2e30 net/openvswitch/flow_netlink.c:2250
ovs_flow_cmd_fill_info+0x420/0x9c0 net/openvswitch/datapath.c:930
ovs_flow_cmd_del+0x53a/0x970 net/openvswitch/datapath.c:1467
...
netlink_rcv_skb+0x156/0x420 net/netlink/af_netlink.c:2556
</TASK>
Allocated by task 9487:
mask_alloc net/openvswitch/flow_table.c:967
flow_mask_insert net/openvswitch/flow_table.c:1012
ovs_flow_tbl_insert+0xea2/0x1a90 net/openvswitch/flow_table.c:1084
ovs_flow_cmd_new+0x7e3/0xd90 net/openvswitch/datapath.c:1086
...
netlink_rcv_skb+0x156/0x420 net/netlink/af_netlink.c:2556
Freed by task 9485:
rcu_free_sheaf+0x1e/0x100 mm/slub.c:5978
rcu_do_batch kernel/rcu/tree.c:2645
rcu_core+0x59c/0x10c0 kernel/rcu/tree.c:2897
handle_softirqs+0x1e4/0x9a0 kernel/softirq.c:622
...
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062
ovs_flow_tbl_remove() must be called after the ovs_flow_cmd_fill_info()
to avoid this race. This also helps with cleaning up the forced cast
and the cosmetic RCU read lock. Before the commit in the Fixes tag the
order did not matter as long as the flow object itself was not freed.
A wider RCU critical section could be another option, but we have a
GFP_KERNEL allocation in the way.
Reported by Trend Micro's Zero Day Initiative as ZDI-CAN-32042. |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix use-after-free in smc_rx_pipe_buf_release()
smc_rx_splice() hands RMB pages to a pipe and takes a socket reference
per entry so the smc_sock stays alive until the reader finishes. The
connection does not: a concurrent close runs smc_conn_free(), which
releases the receive buffer back to the link group pool.
smc_rx_pipe_buf_release() tests sk_state before taking the socket lock.
The state can change between the test and the lock, and
smc_rx_update_cons() then dereferences conn->rmb_desc and walks
conn->lgr, which smc_conn_free() has already released. On the
is_reg_err path smcr_buf_unuse() frees the descriptor outright, so
this is a use-after-free.
Take the socket lock first and test conn->freed instead.
smc_conn_free() sets that flag before releasing anything, and every
caller holds the socket lock. The two paths exclude each other: either
the pipe release runs first with everything valid, or it sees the flag
and skips the update. |
| In the Linux kernel, the following vulnerability has been resolved:
net: skbuff: don't touch shared zerocopy state in skb_tx_error()
skb_tx_error() completes the zerocopy uarg and clears
SKBFL_ALL_ZEROCOPY, and skb_zcopy_downgrade_managed() clears
SKBFL_MANAGED_FRAG_REFS. Both live in skb_shinfo(), which every clone
shares, while the caller only owns the reference it is about to drop.
Through a clone it tells the producer its pages are free and drops
SKBFL_SHARED_FRAG for an skb that is still in flight.
Open vSwitch reaches this with a non-last OVS_ACTION_ATTR_RECIRC:
clone_execute() sends a skb_clone() into ovs_dp_process_packet() while
do_execute_actions() keeps forwarding the original, and skb_clone()
does not privatise the frags here -- skb_orphan_frags() returns early
on SKBFL_DONT_ORPHAN. A flow miss on the clone then strips the marker
from the packet still being forwarded, and a later local ESP delivery
decrypts in place over frags it does not own privately.
Skip it for a cloned skb. Nothing is lost: skb_release_data() clears
the zerocopy state once the last reference to the shared data goes. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: bcd2000: clear the URB pointers on disconnect
bcd2000_free_usb_related_resources() frees both URBs and leaves the
pointers behind:
usb_kill_urb(bcd2k->midi_out_urb);
usb_kill_urb(bcd2k->midi_in_urb);
usb_free_urb(bcd2k->midi_out_urb);
usb_free_urb(bcd2k->midi_in_urb);
The rawmidi device outlives that call. A substream that is still open
when the device is unplugged reaches bcd2000_midi_send() from the
trigger path on close. That function writes to the freed URB and then
hands it to the USB core:
bcd2k->midi_out_urb->transfer_buffer_length = BUFSIZE;
...
ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC);
usb_kill_urb() does not stop a later submission either, so a submit that
races the disconnect can requeue the URB after it has been reaped.
midi_in_urb is exposed the same way: bcd2000_input_complete() resubmits
it from the completion handler.
KASAN on 7.2.0-rc5 (arm64):
BUG: KASAN: slab-use-after-free in bcd2000_midi_send [snd_bcd2000]
Write of size 4 at addr ffff00001827d388 by task bpoc/168
__asan_store4
bcd2000_midi_send [snd_bcd2000]
bcd2000_midi_output_trigger [snd_bcd2000]
snd_rawmidi_kernel_write1
close_substream.part.0
Freed by task 168:
usb_free_urb
bcd2000_disconnect [snd_bcd2000]
BUG: KASAN: slab-use-after-free in usb_submit_urb
Read of size 8 at addr ffff00001827d3b8 by task bpoc/168
Clear both pointers after freeing and test them on the paths that can
still run. Poison the URBs before freeing them: usb_poison_urb() waits
for a running completion handler and rejects any later submission, so
after it returns the input path is quiesced and only the rawmidi trigger
path can still reach bcd2000_midi_send(). No unpoison is needed; the
URBs are freed on the next line.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com> |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: wake linked drain waiters on unlink
snd_pcm_drain() on a linked stream parks an on-stack wait entry on the
drained peer's runtime->sleep, and after schedule_timeout() removes it
only if that peer is still found in the caller's group. If group
membership changes during the wait and the sleep ends by signal or
timeout (so autoremove_wake_function() does not run), finish_wait() is
skipped and snd_pcm_drain() returns with the entry still queued on that
stream's sleep list; a later wake_up() then walks a freed stack frame.
This is reachable by unlinking either the drained or the draining stream.
Unlike the close path (snd_pcm_drop() -> snd_pcm_post_stop()),
snd_pcm_unlink() never wakes the sleep queues. Wake every group member
under the group lock before the membership change, so a linked drainer is
released and drops its entry while the streams are still grouped.
The window was opened when snd_pcm_link_rwsem stopped being held across
the wait and the removal became conditional on group membership (see
Fixes). The later switch to finish_wait() kept that conditional removal,
so the signal/timeout case remained. |
| In the Linux kernel, the following vulnerability has been resolved:
ipvs: do not propagate one-packet flag to synced conns
Synced connections can be created before their destination exists. When
the destination is later added, ip_vs_bind_dest() copies connection flags
from the destination into cp->flags.
IP_VS_CONN_F_ONE_PACKET connections are not synced. If a synced
connection inherits IP_VS_CONN_F_ONE_PACKET while it is already hashed,
expiry can treat it as a one-packet connection and skip unlinking the
existing conn_tab node, leaving stale hash nodes pointing at a freed
struct ip_vs_conn.
Drop IP_VS_CONN_F_ONE_PACKET from destination flags when binding synced
connections. |
| In the Linux kernel, the following vulnerability has been resolved:
can: j1939: transport: j1939_session_fresh_new(): initialize receive buffer
Zero the allocated buffer in j1939_session_fresh_new() to ensure it
contains no residual data.
While there is a potential performance impact if users allocate maximum
sized ETP buffers, most real-world use cases are not noticeably affected
since the maximum known buffer size is typically around 65K.
[mkl: add Message-ID] |
| In the Linux kernel, the following vulnerability has been resolved:
vxlan: re-fetch eth header after route_shortcircuit()
Before route_shortcircuit(), the eth header pointer is cached from eth_hdr(skb).
Inside route_shortcircuit(), pskb_may_pull() can be called, which may
reallocate skb->head.
In this case, returning to vxlan_xmit() leaves the cached eth pointer pointing to
freed memory, leading to a use-after-free when dereferencing eth->h_dest.
Fix this by updating eth = eth_hdr(skb) after calling route_shortcircuit(). |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
This patch replaces the timer API by GC worker approach for
expectations, as it already happened in many other subsystems.
Use the existing conntrack GC worker to iterate over the local list of
expectations in the master conntrack to reap expired expectations.
Check IPS_HELPER_BIT to run GC for expectations, set it on for nft_ct
expectation which nevers sets it. Hold the expectation spinlock while
iterating over the master conntrack expectation list to synchronize with
nf_ct_remove_expectations(). This also performs runtime packet path
garbage collection through the expectation insertion and lookup
functions while walking over one of the chains of the global expectation
hashtables. Unconfirmed conntrack entries are skipped since ct->ext can
be reallocated and dying are skipped since those will be gone soon.
Set on IPS_HELPER_BIT if the helper ct extension is added, then the new
GC worker does not need to bump the ct refcount to check if the ct->ext
helper is available.
This removes the extra bump on the refcount for expectation timers, this
allows to remove several nf_ct_expect_put() calls after the unlink,
after this update only refcount remains at 1 while on the expectation
hashes.
This patch implicitly addresses a race with the existing timer API
allowing an expectation to access a stale exp->master pointer which has
been already released when expectation removal loses races with an
expiring timer, ie. timer_del() reporting false.
Add a new NF_CT_EXPECT_DEAD flag to reap this expectation via GC. This
is needed by nf_conntrack_unexpect_related() which is called in error
paths to invalidate newly created expectations that has been added into
the hashes. These expectactions cannot be inmediately released as GC or
nf_ct_remove_expectations() could race to make it. On expectation
insert, the runtime GC reaps stale expectations before checking the
expectation limit set by policy.
Set current timestamp in nf_ct_expect_alloc(), then add the expectation
policy timeout (or custom timeout specified added on top of this) to
specify the expectation lifetime. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: oss: Serialize readq reset state with q->lock
snd_seq_oss_readq_clear() resets qlen, head, and tail without
q->lock even though the normal reader and producer paths serialize the
same ring state under that spinlock. A reset can therefore race
snd_seq_oss_readq_free() or snd_seq_oss_readq_put_event() and leave
stale records in the queue, drop freshly queued ones, or report the
wrong readiness after wakeup. KCSAN reports a data race between
snd_seq_oss_readq_clear() and snd_seq_oss_readq_free().
Take q->lock while clearing the ring and resetting input_time. Factor
the enqueue logic into a caller-locked helper so
snd_seq_oss_readq_put_timestamp() updates its suppression state under
the same lock instead of racing the reset path.
The buggy scenario involves two paths, with each column showing the
order within that path:
reset path: locked readq updater:
1. snd_seq_oss_reset() or 1. A reader or callback producer
release reaches takes q->lock on the same queue.
snd_seq_oss_readq_clear().
2. snd_seq_oss_readq_clear() 2. The updater tests or modifies
resets qlen, head, tail, qlen, head, and tail.
and input_time.
3. snd_seq_oss_readq_clear() 3. The updater completes its
wakes sleepers on read-modify-write sequence.
q->midi_sleep.
4. Without q->lock, the reset 4. The resulting ring state drives
can overlap the locked later reads and readiness.
update.
KCSAN reports:
BUG: KCSAN: data-race in snd_seq_oss_readq_clear /
snd_seq_oss_readq_free
write to 0xffff8881069fe608 of 4 bytes by task 120516 on cpu 0:
snd_seq_oss_readq_free+0x6c/0x80
snd_seq_oss_read+0xcb/0x250
odev_read+0x38/0x60
vfs_read+0xff/0x600
ksys_read+0xb4/0x140
__x64_sys_read+0x46/0x60
do_syscall_64+0xbb/0x2f0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
read to 0xffff8881069fe608 of 4 bytes by task 120517 on cpu 1:
snd_seq_oss_readq_clear+0x1f/0x90
snd_seq_oss_reset+0xa7/0xf0
snd_seq_oss_ioctl+0x6f6/0x7e0
odev_ioctl+0x56/0xc0
__x64_sys_ioctl+0xd1/0x120
do_syscall_64+0xbb/0x2f0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
value changed: 0x00000001 -> 0x00000000 |
| In the Linux kernel, the following vulnerability has been resolved:
veth: fix NAPI leak in XDP enable error path
During XDP enablement in veth, if xdp_rxq_info_reg() or
xdp_rxq_info_reg_mem_model() fails, the driver rolls back the changes.
However, the rollback loop:
for (i--; i >= start; i--) {
decrements the loop index 'i' before the first iteration. This
correctly skips unregistering the rxq for the failed index 'i' (as
registration failed or was already cleaned up), but it also
erroneously skips calling netif_napi_deli() for rq[i].xdp_napi.
Since netif_napi_add() was already called for index 'i', this leaves
a dangling napi_struct in the device's napi_list. When the veth
device is later destroyed, the freed queue memory (which contains the
leaked NAPI structure) can be reused.
The subsequent device teardown iterates the NAPI list and
corrupts the reallocated memory, leading to UAF.
Fix this by explicitly deleting the NAPI association for the failed
index 'i' before rolling back the successfully configured queues. |
| In the Linux kernel, the following vulnerability has been resolved:
batman-adv: gw: acquire ethernet header only after skb realloc
The pskb_may_pull() called by batadv_get_vid() could reallocate the buffer
behind the skb. Variables which were pointing to the old buffer need to be
reassigned to avoid an use-after-free. |
| In the Linux kernel, the following vulnerability has been resolved:
block: stop the timeout timer when releasing a never added disk
disk_release() undoes blk_mq_init_allocated_queue() for a disk whose
probe failed before add_disk(), but it only calls blk_mq_exit_queue().
Nothing there stops q->timeout, and that timer rolls forward: it stays
pending until it next expires, not until the last request completes.
So if the driver issued any I/O before adding the disk, the
request_queue is freed while still linked into a timer wheel bucket.
Commit 6f8191fdf41d ("block: simplify disk shutdown") dropped the
blk_cleanup_queue() call that used to stop it. __del_gendisk() and
blk_mq_destroy_queue() still do; only the probe failure path lost it.
nvme gets there because nvme_update_ns_info() submits Report Zones or
FDP io-mgmt-recv on ns->queue before the disk is added, so a later
failure - a concurrent reset setting NVME_CTRL_FROZEN, or
device_add_disk() failing - lands in put_disk() with the timer armed:
BUG: KASAN: slab-use-after-free in detach_if_pending+0x30c/0x340
Write of size 8 at addr ffff888004d71310 by task kworker/u8:2/37
__timer_delete_sync+0x156/0x240 kernel/time/timer.c:1621
blk_sync_queue+0x22/0x40 block/blk-core.c:222
nvme_sync_queues+0x100/0x150 drivers/nvme/host/core.c:5362
nvme_reset_work+0x138/0x930 drivers/nvme/host/pci.c:3264
Allocated by task 34:
__blk_mq_alloc_disk+0x33/0x100 block/blk-mq.c:4462
nvme_alloc_ns+0x290/0x3870 drivers/nvme/host/core.c:4146
Freed by task 0:
blk_free_queue_rcu+0x3a/0x50 block/blk-core.c:254
rcu_core+0xc10/0x1730 kernel/rcu/tree.c:2857
The queue being synced there is ctrl->admin_q, only a victim sharing a
timer wheel bucket with the freed queue's dangling entry; other runs
tripped in enqueue_timer(), __run_timers() or blk_mq_timeout_work().
Failing nvme_alloc_ns() with a debug patch makes it deterministic: one
leaked timer trips KASAN within seconds, while 1987 patched releases
produced no splat.
Stop the timer and the queue work items before blk_mq_exit_queue(), like
blk_mq_destroy_queue() does.
Found by FuzzNvme. |
| In the Linux kernel, the following vulnerability has been resolved:
mptcp: options: reset DSS fields in case of unexpected size
A remote peer could send a malformed DSS with a wrong size, followed by
another DSS or MPC + Data. In this case, the first suboption will be
ignored, but leaving some fields written, which could lead to
inconsistency or access uninitialized data.
Explicitly reset the fields that could have been modified in case of
unexpected size. |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: clear fb_info->mode before deleting a videomode
fb_set_var() can delete a mode from info->modelist when userspace
passes FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. The code
checks that the mode being deleted is not the current info->var and
that fbcon is not using it, but it does not check fb_info->mode.
fb_info->mode may still point into the modelist entry being deleted.
If the entry is freed, later mode sysfs reads through show_mode() can
dereference a stale pointer.
Clear fb_info->mode before calling fb_delete_videomode() when it
matches the mode being removed. |
| In the Linux kernel, the following vulnerability has been resolved:
perf: Reject exited events as group leaders
perf_event_remove_on_exec() sets remove-on-exec events to the EXIT state
and detaches their group relationships. The event's file descriptor can
remain open, however, and perf_event_open() currently accepts that event
as a group leader because its early validation rejects only REVOKED and
DEAD events.
A new sibling can consequently be linked to the detached leader. When
the leader is closed, perf_group_detach() observes that its
PERF_ATTACH_GROUP bit is already clear and skips the new sibling. The
sibling then retains a group_leader pointer to the freed event.
Reject group leaders in the EXIT state. Perform the check while holding
the shared context mutex so that an exec in the target task cannot detach
the leader between validation and group attachment.
[peterz: make the earlier test fully consistent] |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: flowtable: publish GC-visible tuple last
nf_flow_table_iterate() only treats original-direction tuple nodes as
owning entries. Publishing the original node first lets GC observe and
free a flow while flow_offload_add() is still inserting the reply node.
Publish the reply node first and the original node last so GC never
sees a partially installed flow.
KASAN can trigger slab-use-after-free read and write reports in the
flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,
flow_offload_lookup, etc.). |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Preserve pointer state for commuted arithmetic
When scalar += pointer is handled in adjust_ptr_min_max_vals(), the
destination register inherits the pointer state from the source pointer.
Copying only selected fields is fragile because pointer provenance is
tracked by several bpf_reg_state fields.
Use the caller's temporary offset register to preserve the scalar operand
while replacing the destination with the full pointer state. This preserves
the frame number for PTR_TO_STACK registers and keeps parent identity
fields consistent. |
| In the Linux kernel, the following vulnerability has been resolved:
udp: fix potential use-after-free in tunnel segmentation
__skb_udp_tunnel_segment() gets the UDP header before ensuring the
tunnel header is in the skb head. If the pull reallocates skb->head,
the saved UDP header pointer is no longer valid.
Get the UDP header after the pull to avoid a potential use-after-free. |
