| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: isci: Fix use-after-free in device removal path
The ISCI completion tasklet is initialized in isci_host_alloc()
(drivers/scsi/isci/init.c:496) and scheduled from both MSI-X and legacy
interrupt handlers (drivers/scsi/isci/host.c:223,613).
isci_host_deinit() stops the controller and waits for stop completion,
but it never kills completion_tasklet before teardown continues. A
top-of-function tasklet_kill() is not sufficient here: interrupts are
only disabled when isci_host_stop_complete() runs, so until
wait_for_stop() returns the IRQ handlers can still requeue the
tasklet. The tasklet callback also re-enables interrupts after draining
completions, so killing the tasklet before the source is quiesced leaves
the same race open.
Once wait_for_stop() returns, no further IRQ-driven scheduling can
occur. Kill completion_tasklet there so teardown cannot race a queued
tasklet running on a dead ihost. On remove or unload, the stale callback
can otherwise dereference ihost and touch ihost->smu_registers after the
host lifetime ends.
A UML + KASAN analogue reproduced the failure class both with no
tasklet_kill() and with tasklet_kill() placed before source quiesce, and
stayed clean once the kill happened after quiescing the scheduling
source.
This mirrors commit f6ab594672d4 ("scsi: aic94xx: fix use-after-free in
device removal path"), but ISCI needs the kill after wait_for_stop(). |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: fix use-after-free in store_modes()
store_modes() replaces a framebuffer's modelist with modes from userspace.
On success it frees the old modelist with fb_destroy_modelist(). Two
fields still point into that freed list.
One pointer is fb_display[i].mode, the mode a console is using.
fbcon_new_modelist() moves these pointers to the new list. It only does so
for consoles still mapped to the framebuffer. An unmapped console is
skipped and keeps its stale pointer. Unbinding fbcon, for example, sets
con2fb_map[i] to -1 but leaves fb_display[i].mode set. An
FBIOPUT_VSCREENINFO ioctl with FB_ACTIVATE_INV_MODE later reaches
fbcon_mode_deleted(). That function reads the stale fb_display[i].mode
through fb_mode_is_equal(). The read is a use-after-free.
The other pointer is fb_info->mode, the current mode. It is set through
the mode sysfs attribute. store_modes() does not update fb_info->mode, so
it is left pointing into the freed list. show_mode(), the attribute's read
handler, dereferences the stale fb_info->mode through mode_string(). The
read is a use-after-free.
Clear both pointers before freeing the list. Commit a1f305893074 ("fbcon:
Set fb_display[i]->mode to NULL when the mode is released") added the
helper fbcon_delete_modelist(). It clears every fb_display[i].mode that
points into a given list. So far it is called only from the unregister
path. Call it from store_modes() too, and set fb_info->mode to NULL. |
| In the Linux kernel, the following vulnerability has been resolved:
gfs2: fix use-after-free in gfs2_qd_dealloc
gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),
accesses the superblock object sdp through qd->qd_sbd after freeing qd.
It does so to decrement sd_quota_count and wake up sd_kill_wait.
However, by the time the RCU callback runs, gfs2_put_super() may have
already freed sdp via free_sbd(). This can happen when
gfs2_quota_cleanup() is called during unmount: it disposes of quota
objects via call_rcu() and then waits on sd_kill_wait with a 60-second
timeout. If the timeout expires, or if gfs2_gl_hash_clear() triggers
additional qd_put() calls that schedule more RCU callbacks after the
wait completes, gfs2_put_super() will proceed to free the superblock
while RCU callbacks referencing it are still pending.
Add an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure
all pending RCU callbacks (including gfs2_qd_dealloc) have completed
before the superblock is freed. |
| In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Block PASID attachment to nested domain with dirty tracking
Kernel lacks dirty tracking support on nested domain attached to PASID,
fails the attachment early if nesting parent domain is dirty tracking
configured, otherwise dirty pages would be lost. |
| In the Linux kernel, the following vulnerability has been resolved:
hsr: Remove WARN_ONCE() in hsr_addr_is_self().
syzbot reported the warning [0] in hsr_addr_is_self(),
whose assumption is simply wrong.
hsr->self_node is cleared in hsr_del_self_node(), which
is called from hsr_dellink().
Since dev->rtnl_link_ops->dellink() is called before
unregister_netdevice_many(), there is a window when
user can find the device but without hsr->self_node.
Let's remove WARN_ONCE() in hsr_addr_is_self().
[0]:
HSR: No self node
WARNING: net/hsr/hsr_framereg.c:39 at hsr_addr_is_self+0x211/0x3f0 net/hsr/hsr_framereg.c:39, CPU#0: syz.4.16848/17220
Modules linked in:
CPU: 0 UID: 0 PID: 17220 Comm: syz.4.16848 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:hsr_addr_is_self+0x211/0x3f0 net/hsr/hsr_framereg.c:39
Code: 33 2f 41 0f b7 dd 89 ee 09 de 31 ff e8 c8 b4 c6 f6 09 dd 74 54 e8 0f b0 c6 f6 31 ed eb 53 e8 06 b0 c6 f6 48 8d 3d 2f 50 9c 04 <67> 48 0f b9 3a 31 ed eb 42 e8 c1 13 1f 00 89 c5 31 ff 89 c6 e8 96
RSP: 0018:ffffc900041c70e0 EFLAGS: 00010283
RAX: ffffffff8afdc6ca RBX: ffffffff8afdc4e6 RCX: 0000000000080000
RDX: ffffc90010493000 RSI: 0000000000000948 RDI: ffffffff8f9a1700
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900041c71e8 R11: fffff52000838e3f R12: dffffc0000000000
R13: ffff888041f9e3c0 R14: ffff888086ee3802 R15: 0000000000000000
FS: 00007f6fe985d6c0(0000) GS:ffff888126176000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f80bd437dac CR3: 0000000025096000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
check_local_dest net/hsr/hsr_forward.c:592 [inline]
fill_frame_info net/hsr/hsr_forward.c:728 [inline]
hsr_forward_skb+0xa11/0x2a80 net/hsr/hsr_forward.c:739
hsr_dev_xmit+0x253/0x370 net/hsr/hsr_device.c:236
__netdev_start_xmit include/linux/netdevice.h:5368 [inline]
netdev_start_xmit include/linux/netdevice.h:5377 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2df/0x860 net/core/dev.c:3904
__dev_queue_xmit+0x1428/0x3900 net/core/dev.c:4870
neigh_output include/net/neighbour.h:556 [inline]
ip_finish_output2+0xcec/0x10b0 net/ipv4/ip_output.c:237
ip_send_skb net/ipv4/ip_output.c:1510 [inline]
ip_push_pending_frames+0x8b/0x110 net/ipv4/ip_output.c:1530
raw_sendmsg+0x1547/0x1a50 net/ipv4/raw.c:659
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x7da/0x9c0 net/socket.c:2698
___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
__sys_sendmsg net/socket.c:2784 [inline]
__do_sys_sendmsg net/socket.c:2789 [inline]
__se_sys_sendmsg net/socket.c:2787 [inline]
__x64_sys_sendmsg+0x1c3/0x2a0 net/socket.c:2787
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6feb62ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6fe985d028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6feb8a6090 RCX: 00007f6feb62ce59
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f6feb6c2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6feb8a6128 R14: 00007f6feb8a6090 R15: 00007ffcf01cc488
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack: destroy stale expectfn expectations on unregister
NAT helpers such as nf_nat_h323 store a raw pointer to module text in
exp->expectfn (e.g. ip_nat_q931_expect). nf_ct_helper_expectfn_unregister()
only unlinks the callback descriptor and never walks the expectation table,
so an expectation pending at module removal survives with a dangling
exp->expectfn into freed module text.
When the expected connection arrives, init_conntrack() invokes
exp->expectfn(), now a stale pointer into the unloaded module. Reproduced
on a KASAN build by loading the H.323 helpers, creating a Q.931
expectation, unloading nf_nat_h323, then connecting to the expected port:
Oops: int3: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:0xffffffffa06102d1
init_conntrack.isra.0 (net/netfilter/nf_conntrack_core.c:1862)
nf_conntrack_in (net/netfilter/nf_conntrack_core.c:2049)
ipv4_conntrack_local (net/netfilter/nf_conntrack_proto.c:223)
nf_hook_slow (net/netfilter/core.c:619)
__ip_local_out (net/ipv4/ip_output.c:120)
__tcp_transmit_skb (net/ipv4/tcp_output.c:1715)
tcp_connect (net/ipv4/tcp_output.c:4374)
tcp_v4_connect (net/ipv4/tcp_ipv4.c:345)
__sys_connect (net/socket.c:2167)
Modules linked in: nf_conntrack_h323 [last unloaded: nf_nat_h323]
Reaching the dangling state requires CAP_SYS_MODULE in the initial user
namespace to remove a NAT helper that still has live expectations, so this
is a robustness fix; leaving an expectation pointing at freed text is wrong
regardless.
Add nf_ct_helper_expectfn_destroy(), which walks the expectation table and
drops every expectation whose ->expectfn matches the descriptor being torn
down. Call it from each NAT helper's exit path after the existing RCU grace
period, so no expectation outlives the code it points at and no extra
synchronize_rcu() is introduced. With the fix, the same reproducer runs to
completion without the Oops. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/virtio: Fix driver removal with disabled KMS
DRM atomic and modesetting aren't initialized if virtio-gpu driver built
with disabled KMS, leading to access of uninitialized data on driver
removal/unbinding and crashing kernel. Fix it by skipping shutting down
atomic core with unavailable KMS. |
| In the Linux kernel, the following vulnerability has been resolved:
mailbox: mailbox-test: free channels on probe error
On probe error, free the previously obtained channels. This not only
prevents a leak, but also UAF scenarios because the client structure
will be removed nonetheless because it was allocated with devm. |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS
A logic flaw in __smc_setsockopt() allows a local unprivileged user to
cause a Denial of Service (DoS) by holding the socket lock indefinitely.
The function __smc_setsockopt() calls copy_from_sockptr() while holding
lock_sock(sk). By passing a userfaultfd-monitored memory page (or
FUSE-backed memory on systems where unprivileged userfaultfd is disabled)
as the optval, an attacker can halt execution during the copy operation,
keeping the lock held.
Combined with asynchronous tear-down operations like shutdown(), this
exhausts the kernel wq (kworkers) and triggers the hung task watchdog.
[ 240.123456] INFO: task kworker/u8:2 blocked for more than 120 seconds.
[ 240.123489] Call Trace:
[ 240.123501] smc_shutdown+...
[ 240.123512] lock_sock_nested+...
This patch moves the user-space copy outside the lock_sock() critical
section to prevent the issue. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: synproxy: add mutex to guard hook reference counting
As the synproxy infrastructure register netfilter hooks on-demand when a
user adds the first iptables target or nftables expression, if done
concurrently they can race each other.
Introduce a mutex to serialize the refcount control blocks access from
both frontends. While a per namespace mutex might be more efficient, it
is not needed for target/expression like SYNPROXY. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_exthdr: fix register tracking for F_PRESENT flag
nft_exthdr_init() passes user-controlled priv->len to
nft_parse_register_store(), which marks that many bytes in the
register bitmap as initialized. However, when NFT_EXTHDR_F_PRESENT
is set, the eval paths write only 1 byte (nft_reg_store8) or
4 bytes (*dest = 0 on TCP/DCCP error path). When len > 4,
registers beyond the first are never written, retaining
uninitialized stack data from nft_regs.
Bail out if userspace requests too much data when F_PRESENT is set. |
| In the Linux kernel, the following vulnerability has been resolved:
nvmem: core: fix use-after-free bugs in error paths
Fix several instances of error paths in which we call
__nvmem_device_put() - which may end up freeing the underlying memory
and other resources - and then keep on using the nvmem structure. Always
put the reference to the nvmem device as the last step before returning
the error code. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/xe/display: fix oops in suspend/shutdown without display
The xe driver keeps track of whether to probe display, and whether
display hardware is there, using xe->info.probe_display. It gets set to
false if there's no display after intel_display_device_probe(). However,
the display may also be disabled via fuses, detected at a later time in
intel_display_device_info_runtime_init().
In this case, the xe driver does for_each_intel_crtc() on uninitialized
mode config in xe_display_flush_cleanup_work(), leading to a NULL
pointer dereference, and generally calls display code with display info
cleared.
Check for intel_display_device_present() after
intel_display_device_info_runtime_init(), and reset
xe->info.probe_display as necessary. Also do unset_display_features()
for completeness, although display runtime init has already done
that. This will need to be unified across all cases later.
Move intel_display_device_info_runtime_init() call slightly earlier,
similar to i915, to avoid a bunch of unnecessary setup for no display
cases.
Note #1: The xe driver has no business doing low level display plumbing
like for_each_intel_crtc() to begin with. It all needs to happen in
display code.
Note #2: The actual bug is present already in commit 44e694958b95
("drm/xe/display: Implement display support"), but the oops was likely
introduced later at commit ddf6492e0e50 ("drm/xe/display: Make display
suspend/resume work on discrete").
(cherry picked from commit 7c3eb9f47533220888a67266448185fd0775d4da) |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_fib: fix stale stack leak via the OIFNAME register
For NFT_FIB_RESULT_OIFNAME the destination register is declared with
len = IFNAMSIZ (four 32-bit registers), but on the lookup-fail,
RTN_LOCAL and oif-mismatch paths nft_fib{4,6}_eval() only writes one
register via "*dest = 0". The remaining three registers are left as
whatever was on the stack in nft_do_chain()'s struct nft_regs, and a
downstream expression that loads the register span can leak that
uninitialised kernel stack to userspace.
The NFTA_FIB_F_PRESENT existence check has the same shape: it is only
meaningful for NFT_FIB_RESULT_OIF, yet it was accepted for any result type
while the eval stores a single byte via nft_reg_store8(), leaving the rest
of the declared span stale.
Fix both:
- replace the bare "*dest = 0" in the eval with nft_fib_store_result(),
which strscpy_pad()s the whole IFNAMSIZ for OIFNAME (and is already
used on the other early-return path), and
- restrict NFTA_FIB_F_PRESENT to NFT_FIB_RESULT_OIF and declare its
destination as a single u8, so the marked span matches the one byte
the eval writes. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap
The bpf_lwt_xmit_push_encap helper needs to access skb_dst(skb)->dev to
calculate the needed headroom:
err = skb_cow_head(skb,
len + LL_RESERVED_SPACE(skb_dst(skb)->dev));
But skb->_skb_refdst may not be initialized when the skb is set up by
bpf_prog_test_run_skb function. Executing bpf_lwt_push_ip_encap function
in this scenario will trigger null pointer dereference, causing a kernel
crash as Yinhao reported:
[ 105.186365] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 105.186382] #PF: supervisor read access in kernel mode
[ 105.186388] #PF: error_code(0x0000) - not-present page
[ 105.186393] PGD 121d3d067 P4D 121d3d067 PUD 106c83067 PMD 0
[ 105.186404] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 105.186412] CPU: 3 PID: 3250 Comm: poc Kdump: loaded Not tainted 6.19.0-rc5 #1
[ 105.186423] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 105.186427] RIP: 0010:bpf_lwt_push_ip_encap+0x1eb/0x520
[ 105.186443] Code: 0f 84 de 01 00 00 0f b7 4a 04 66 85 c9 0f 85 47 01 00 00 31 c0 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 48 8b 73 58 48 83 e6 fe <48> 8b 36 0f b7 be ec 00 00 00 0f b7 b6 e6 00 00 00 01 fe 83 e6 f0
[ 105.186449] RSP: 0018:ffffbb0e0387bc50 EFLAGS: 00010246
[ 105.186455] RAX: 000000000000004e RBX: ffff94c74e036500 RCX: ffff94c74874da00
[ 105.186460] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff94c74e036500
[ 105.186463] RBP: 0000000000000001 R08: 0000000000000002 R09: 0000000000000000
[ 105.186467] R10: ffffbb0e0387bd50 R11: 0000000000000000 R12: ffffbb0e0387bc98
[ 105.186471] R13: 0000000000000014 R14: 0000000000000000 R15: 0000000000000002
[ 105.186484] FS: 00007f166aa4d680(0000) GS:ffff94c8b7780000(0000) knlGS:0000000000000000
[ 105.186490] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 105.186494] CR2: 0000000000000000 CR3: 000000015eade001 CR4: 0000000000770ee0
[ 105.186499] PKRU: 55555554
[ 105.186502] Call Trace:
[ 105.186507] <TASK>
[ 105.186513] bpf_lwt_xmit_push_encap+0x2b/0x40
[ 105.186522] bpf_prog_a75eaad51e517912+0x41/0x49
[ 105.186536] ? kvm_clock_get_cycles+0x18/0x30
[ 105.186547] ? ktime_get+0x3c/0xa0
[ 105.186554] bpf_test_run+0x195/0x320
[ 105.186563] ? bpf_test_run+0x10f/0x320
[ 105.186579] bpf_prog_test_run_skb+0x2f5/0x4f0
[ 105.186590] __sys_bpf+0x69c/0xa40
[ 105.186603] __x64_sys_bpf+0x1e/0x30
[ 105.186611] do_syscall_64+0x59/0x110
[ 105.186620] entry_SYSCALL_64_after_hwframe+0x76/0xe0
[ 105.186649] RIP: 0033:0x7f166a97455d
Temporarily add the setting of skb->_skb_refdst before bpf_test_run to resolve the issue. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix RCU stall in bpf_fd_array_map_clear()
Add a missing cond_resched() in bpf_fd_array_map_clear() loop.
For PROG_ARRAY maps with many entries this loop calls
prog_array_map_poke_run() per entry which can be expensive, and
without yielding this can cause RCU stalls under load:
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 30932 Comm: kworker/0:2 Not tainted 6.14.0-13195-g967e8def1100 #2 PREEMPT(undef)
Workqueue: events prog_array_map_clear_deferred
RIP: 0010:write_comp_data+0x38/0x90 kernel/kcov.c:246
Call Trace:
<TASK>
prog_array_map_poke_run+0x77/0x380 kernel/bpf/arraymap.c:1096
__fd_array_map_delete_elem+0x197/0x310 kernel/bpf/arraymap.c:925
bpf_fd_array_map_clear kernel/bpf/arraymap.c:1000 [inline]
prog_array_map_clear_deferred+0x119/0x1b0 kernel/bpf/arraymap.c:1141
process_one_work+0x898/0x19d0 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x770/0x10b0 kernel/workqueue.c:3400
kthread+0x465/0x880 kernel/kthread.c:464
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x19/0x30 arch/x86/entry/entry_64.S:245
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_ldisc: Clear HCI_UART_PROTO_INIT on error
When hci_register_dev() fails in hci_uart_register_dev()
HCI_UART_PROTO_INIT is not cleared before calling hu->proto->close(hu)
and setting hu->hdev to NULL. This means incoming UART data will reach
the protocol-specific recv handler in hci_uart_tty_receive() after
resources are freed.
Clear HCI_UART_PROTO_INIT with a write lock before calling
hu->proto->close() and setting hu->hdev to NULL. The write lock ensures
all active readers have completed and no new reader can enter the
protocol recv path before resources are freed.
This allows the protocol-specific recv functions to remove the
"HCI_UART_REGISTERED" guard without risking a null pointer dereference
if hci_register_dev() fails. |
| In the Linux kernel, the following vulnerability has been resolved:
dm cache: fix write hang in passthrough mode
The invalidate_remove() function has incomplete logic for handling write
hit bios after cache invalidation. It sets up the remapping for the
overwrite_bio but then drops it immediately without submission, causing
write operations to hang.
Fix by adding a new invalidate_committed() continuation that submits
the remapped writes to the cache origin after metadata commit completes,
while using the overwrite_endio hook to ensure proper completion
sequencing. This maintains existing coherency. Also improve error
handling in invalidate_complete() to preserve the original error status
instead of using bio_io_error() unconditionally. |
| In the Linux kernel, the following vulnerability has been resolved:
gfs2: prevent NULL pointer dereference during unmount
When flushing out outstanding glock work during an unmount, gfs2_log_flush()
can be called when sdp->sd_jdesc has already been deallocated and sdp->sd_jdesc
is NULL. Commit 35264909e9d1 ("gfs2: Fix NULL pointer dereference in
gfs2_log_flush") added a check for that to gfs2_log_flush() itself, but it
missed the sdp->sd_jdesc dereference in gfs2_log_release(). Fix that. |
| In the Linux kernel, the following vulnerability has been resolved:
netdevsim: zero initialize struct iphdr in dummy sk_buff
Syzbot reports a KMSAN uninit-value originating from
nsim_dev_trap_skb_build, with the allocation also
being performed in the same function.
Fix this by calling skb_put_zero instead of skb_put to
guarantee zero initialization of the whole IP header. |