Linux: >> Linux Kernel >> 6.1.9 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:
power: supply: bq25890: Fix external_power_changed race
bq25890_charger_external_power_changed() dereferences bq->charger,
which gets sets in bq25890_power_supply_init() like this:
bq->charger = devm_power_supply_register(bq->dev, &bq->desc, &psy_cfg);
As soon as devm_power_supply_register() has called device_add()
the external_power_changed callback can get called. So there is a window
where bq25890_charger_external_power_changed() may get called while
bq->charger has not been set yet leading to a NULL pointer dereference.
This race hits during boot sometimes on a Lenovo Yoga Book 1 yb1-x90f
when the cht_wcove_pwrsrc (extcon) power_supply is done with detecting
the connected charger-type which happens to exactly hit the small window:
BUG: kernel NULL pointer dereference, address: 0000000000000018
<snip>
RIP: 0010:__power_supply_is_supplied_by+0xb/0xb0
<snip>
Call Trace:
<TASK>
__power_supply_get_supplier_property+0x19/0x50
class_for_each_device+0xb1/0xe0
power_supply_get_property_from_supplier+0x2e/0x50
bq25890_charger_external_power_changed+0x38/0x1b0 [bq25890_charger]
__power_supply_changed_work+0x30/0x40
class_for_each_device+0xb1/0xe0
power_supply_changed_work+0x5f/0xe0
<snip>
Fixing this is easy. The external_power_changed callback gets passed
the power_supply which will eventually get stored in bq->charger,
so bq25890_charger_external_power_changed() can simply directly use
the passed in psy argument which is always valid.
CVSS Score
4.7
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:
usb: ucsi_acpi: Increase the command completion timeout
Commit 130a96d698d7 ("usb: typec: ucsi: acpi: Increase command
completion timeout value") increased the timeout from 5 seconds
to 60 seconds due to issues related to alternate mode discovery.
After the alternate mode discovery switch to polled mode
the timeout was reduced, but instead of being set back to
5 seconds it was reduced to 1 second.
This is causing problems when using a Lenovo ThinkPad X1 yoga gen7
connected over Type-C to a LG 27UL850-W (charging DP over Type-C).
When the monitor is already connected at boot the following error
is logged: "PPM init failed (-110)", /sys/class/typec is empty and
on unplugging the NULL pointer deref fixed earlier in this series
happens.
When the monitor is connected after boot the following error
is logged instead: "GET_CONNECTOR_STATUS failed (-110)".
Setting the timeout back to 5 seconds fixes both cases.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
x86/resctrl: Clear staged_config[] before and after it is used
As a temporary storage, staged_config[] in rdt_domain should be cleared
before and after it is used. The stale value in staged_config[] could
cause an MSR access error.
Here is a reproducer on a system with 16 usable CLOSIDs for a 15-way L3
Cache (MBA should be disabled if the number of CLOSIDs for MB is less than
16.) :
mount -t resctrl resctrl -o cdp /sys/fs/resctrl
mkdir /sys/fs/resctrl/p{1..7}
umount /sys/fs/resctrl/
mount -t resctrl resctrl /sys/fs/resctrl
mkdir /sys/fs/resctrl/p{1..8}
An error occurs when creating resource group named p8:
unchecked MSR access error: WRMSR to 0xca0 (tried to write 0x00000000000007ff) at rIP: 0xffffffff82249142 (cat_wrmsr+0x32/0x60)
Call Trace:
<IRQ>
__flush_smp_call_function_queue+0x11d/0x170
__sysvec_call_function+0x24/0xd0
sysvec_call_function+0x89/0xc0
</IRQ>
<TASK>
asm_sysvec_call_function+0x16/0x20
When creating a new resource control group, hardware will be configured
by the following process:
rdtgroup_mkdir()
rdtgroup_mkdir_ctrl_mon()
rdtgroup_init_alloc()
resctrl_arch_update_domains()
resctrl_arch_update_domains() iterates and updates all resctrl_conf_type
whose have_new_ctrl is true. Since staged_config[] holds the same values as
when CDP was enabled, it will continue to update the CDP_CODE and CDP_DATA
configurations. When group p8 is created, get_config_index() called in
resctrl_arch_update_domains() will return 16 and 17 as the CLOSIDs for
CDP_CODE and CDP_DATA, which will be translated to an invalid register -
0xca0 in this scenario.
Fix it by clearing staged_config[] before and after it is used.
[reinette: re-order commit tags]
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