Linux: >> Linux Kernel >> 5.8.13 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm: fix zswap writeback race condition
The zswap writeback mechanism can cause a race condition resulting in
memory corruption, where a swapped out page gets swapped in with data that
was written to a different page.
The race unfolds like this:
1. a page with data A and swap offset X is stored in zswap
2. page A is removed off the LRU by zpool driver for writeback in
zswap-shrink work, data for A is mapped by zpool driver
3. user space program faults and invalidates page entry A, offset X is
considered free
4. kswapd stores page B at offset X in zswap (zswap could also be
full, if so, page B would then be IOed to X, then skip step 5.)
5. entry A is replaced by B in tree->rbroot, this doesn't affect the
local reference held by zswap-shrink work
6. zswap-shrink work writes back A at X, and frees zswap entry A
7. swapin of slot X brings A in memory instead of B
The fix:
Once the swap page cache has been allocated (case ZSWAP_SWAPCACHE_NEW),
zswap-shrink work just checks that the local zswap_entry reference is
still the same as the one in the tree. If it's not the same it means that
it's either been invalidated or replaced, in both cases the writeback is
aborted because the local entry contains stale data.
Reproducer:
I originally found this by running `stress` overnight to validate my work
on the zswap writeback mechanism, it manifested after hours on my test
machine. The key to make it happen is having zswap writebacks, so
whatever setup pumps /sys/kernel/debug/zswap/written_back_pages should do
the trick.
In order to reproduce this faster on a vm, I setup a system with ~100M of
available memory and a 500M swap file, then running `stress --vm 1
--vm-bytes 300000000 --vm-stride 4000` makes it happen in matter of tens
of minutes. One can speed things up even more by swinging
/sys/module/zswap/parameters/max_pool_percent up and down between, say, 20
and 1; this makes it reproduce in tens of seconds. It's crucial to set
`--vm-stride` to something other than 4096 otherwise `stress` won't
realize that memory has been corrupted because all pages would have the
same data.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c
The missing IP_SET_HASH_WITH_NET0 macro in ip_set_hash_netportnet can
lead to the use of wrong `CIDR_POS(c)` for calculating array offsets,
which can lead to integer underflow. As a result, it leads to slab
out-of-bound access.
This patch adds back the IP_SET_HASH_WITH_NET0 macro to
ip_set_hash_netportnet to address the issue.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
irqchip/ti-sci: Fix refcount leak in ti_sci_intr_irq_domain_probe
of_irq_find_parent() returns a node pointer with refcount incremented,
We should use of_node_put() on it when not needed anymore.
Add missing of_node_put() to avoid refcount leak.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
udf: Fix uninitialized array access for some pathnames
For filenames that begin with . and are between 2 and 5 characters long,
UDF charset conversion code would read uninitialized memory in the
output buffer. The only practical impact is that the name may be prepended a
"unification hash" when it is not actually needed but still it is good
to fix this.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix null pointer dereference in tracing_err_log_open()
Fix an issue in function 'tracing_err_log_open'.
The function doesn't call 'seq_open' if the file is opened only with
write permissions, which results in 'file->private_data' being left as null.
If we then use 'lseek' on that opened file, 'seq_lseek' dereferences
'file->private_data' in 'mutex_lock(&m->lock)', resulting in a kernel panic.
Writing to this node requires root privileges, therefore this bug
has very little security impact.
Tracefs node: /sys/kernel/tracing/error_log
Example Kernel panic:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038
Call trace:
mutex_lock+0x30/0x110
seq_lseek+0x34/0xb8
__arm64_sys_lseek+0x6c/0xb8
invoke_syscall+0x58/0x13c
el0_svc_common+0xc4/0x10c
do_el0_svc+0x24/0x98
el0_svc+0x24/0x88
el0t_64_sync_handler+0x84/0xe4
el0t_64_sync+0x1b4/0x1b8
Code: d503201f aa0803e0 aa1f03e1 aa0103e9 (c8e97d02)
---[ end trace 561d1b49c12cf8a5 ]---
Kernel panic - not syncing: Oops: Fatal exception
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
vfio/type1: prevent underflow of locked_vm via exec()
When a vfio container is preserved across exec, the task does not change,
but it gets a new mm with locked_vm=0, and loses the count from existing
dma mappings. If the user later unmaps a dma mapping, locked_vm underflows
to a large unsigned value, and a subsequent dma map request fails with
ENOMEM in __account_locked_vm.
To avoid underflow, grab and save the mm at the time a dma is mapped.
Use that mm when adjusting locked_vm, rather than re-acquiring the saved
task's mm, which may have changed. If the saved mm is dead, do nothing.
locked_vm is incremented for existing mappings in a subsequent patch.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
xfrm: add NULL check in xfrm_update_ae_params
Normally, x->replay_esn and x->preplay_esn should be allocated at
xfrm_alloc_replay_state_esn(...) in xfrm_state_construct(...), hence the
xfrm_update_ae_params(...) is okay to update them. However, the current
implementation of xfrm_new_ae(...) allows a malicious user to directly
dereference a NULL pointer and crash the kernel like below.
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 8253067 P4D 8253067 PUD 8e0e067 PMD 0
Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 PID: 98 Comm: poc.npd Not tainted 6.4.0-rc7-00072-gdad9774deaf1 #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.o4
RIP: 0010:memcpy_orig+0xad/0x140
Code: e8 4c 89 5f e0 48 8d 7f e0 73 d2 83 c2 20 48 29 d6 48 29 d7 83 fa 10 72 34 4c 8b 06 4c 8b 4e 08 c
RSP: 0018:ffff888008f57658 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff888008bd0000 RCX: ffffffff8238e571
RDX: 0000000000000018 RSI: ffff888007f64844 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888008f57818
R13: ffff888007f64aa4 R14: 0000000000000000 R15: 0000000000000000
FS: 00000000014013c0(0000) GS:ffff88806d600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000054d8000 CR4: 00000000000006f0
Call Trace:
<TASK>
? __die+0x1f/0x70
? page_fault_oops+0x1e8/0x500
? __pfx_is_prefetch.constprop.0+0x10/0x10
? __pfx_page_fault_oops+0x10/0x10
? _raw_spin_unlock_irqrestore+0x11/0x40
? fixup_exception+0x36/0x460
? _raw_spin_unlock_irqrestore+0x11/0x40
? exc_page_fault+0x5e/0xc0
? asm_exc_page_fault+0x26/0x30
? xfrm_update_ae_params+0xd1/0x260
? memcpy_orig+0xad/0x140
? __pfx__raw_spin_lock_bh+0x10/0x10
xfrm_update_ae_params+0xe7/0x260
xfrm_new_ae+0x298/0x4e0
? __pfx_xfrm_new_ae+0x10/0x10
? __pfx_xfrm_new_ae+0x10/0x10
xfrm_user_rcv_msg+0x25a/0x410
? __pfx_xfrm_user_rcv_msg+0x10/0x10
? __alloc_skb+0xcf/0x210
? stack_trace_save+0x90/0xd0
? filter_irq_stacks+0x1c/0x70
? __stack_depot_save+0x39/0x4e0
? __kasan_slab_free+0x10a/0x190
? kmem_cache_free+0x9c/0x340
? netlink_recvmsg+0x23c/0x660
? sock_recvmsg+0xeb/0xf0
? __sys_recvfrom+0x13c/0x1f0
? __x64_sys_recvfrom+0x71/0x90
? do_syscall_64+0x3f/0x90
? entry_SYSCALL_64_after_hwframe+0x72/0xdc
? copyout+0x3e/0x50
netlink_rcv_skb+0xd6/0x210
? __pfx_xfrm_user_rcv_msg+0x10/0x10
? __pfx_netlink_rcv_skb+0x10/0x10
? __pfx_sock_has_perm+0x10/0x10
? mutex_lock+0x8d/0xe0
? __pfx_mutex_lock+0x10/0x10
xfrm_netlink_rcv+0x44/0x50
netlink_unicast+0x36f/0x4c0
? __pfx_netlink_unicast+0x10/0x10
? netlink_recvmsg+0x500/0x660
netlink_sendmsg+0x3b7/0x700
This Null-ptr-deref bug is assigned CVE-2023-3772. And this commit
adds additional NULL check in xfrm_update_ae_params to fix the NPD.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
igb: Fix igb_down hung on surprise removal
In a setup where a Thunderbolt hub connects to Ethernet and a display
through USB Type-C, users may experience a hung task timeout when they
remove the cable between the PC and the Thunderbolt hub.
This is because the igb_down function is called multiple times when
the Thunderbolt hub is unplugged. For example, the igb_io_error_detected
triggers the first call, and the igb_remove triggers the second call.
The second call to igb_down will block at napi_synchronize.
Here's the call trace:
__schedule+0x3b0/0xddb
? __mod_timer+0x164/0x5d3
schedule+0x44/0xa8
schedule_timeout+0xb2/0x2a4
? run_local_timers+0x4e/0x4e
msleep+0x31/0x38
igb_down+0x12c/0x22a [igb 6615058754948bfde0bf01429257eb59f13030d4]
__igb_close+0x6f/0x9c [igb 6615058754948bfde0bf01429257eb59f13030d4]
igb_close+0x23/0x2b [igb 6615058754948bfde0bf01429257eb59f13030d4]
__dev_close_many+0x95/0xec
dev_close_many+0x6e/0x103
unregister_netdevice_many+0x105/0x5b1
unregister_netdevice_queue+0xc2/0x10d
unregister_netdev+0x1c/0x23
igb_remove+0xa7/0x11c [igb 6615058754948bfde0bf01429257eb59f13030d4]
pci_device_remove+0x3f/0x9c
device_release_driver_internal+0xfe/0x1b4
pci_stop_bus_device+0x5b/0x7f
pci_stop_bus_device+0x30/0x7f
pci_stop_bus_device+0x30/0x7f
pci_stop_and_remove_bus_device+0x12/0x19
pciehp_unconfigure_device+0x76/0xe9
pciehp_disable_slot+0x6e/0x131
pciehp_handle_presence_or_link_change+0x7a/0x3f7
pciehp_ist+0xbe/0x194
irq_thread_fn+0x22/0x4d
? irq_thread+0x1fd/0x1fd
irq_thread+0x17b/0x1fd
? irq_forced_thread_fn+0x5f/0x5f
kthread+0x142/0x153
? __irq_get_irqchip_state+0x46/0x46
? kthread_associate_blkcg+0x71/0x71
ret_from_fork+0x1f/0x30
In this case, igb_io_error_detected detaches the network interface
and requests a PCIE slot reset, however, the PCIE reset callback is
not being invoked and thus the Ethernet connection breaks down.
As the PCIE error in this case is a non-fatal one, requesting a
slot reset can be avoided.
This patch fixes the task hung issue and preserves Ethernet
connection by ignoring non-fatal PCIE errors.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid deadlock in fs reclaim with page writeback
Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:
CPU0 CPU1
ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever
Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Pointer may be dereferenced
Klocwork tool reported pointer 'rport' returned from call to function
fc_bsg_to_rport() may be NULL and will be dereferenced.
Add a fix to validate rport before dereferencing.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15