Linux: >> Linux Kernel >> 4.17.12 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
kernfs: fix use-after-free in __kernfs_remove
Syzkaller managed to trigger concurrent calls to
kernfs_remove_by_name_ns() for the same file resulting in
a KASAN detected use-after-free. The race occurs when the root
node is freed during kernfs_drain().
To prevent this acquire an additional reference for the root
of the tree that is removed before calling __kernfs_remove().
Found by syzkaller with the following reproducer (slab_nomerge is
required):
syz_mount_image$ext4(0x0, &(0x7f0000000100)='./file0\x00', 0x100000, 0x0, 0x0, 0x0, 0x0)
r0 = openat(0xffffffffffffff9c, &(0x7f0000000080)='/proc/self/exe\x00', 0x0, 0x0)
close(r0)
pipe2(&(0x7f0000000140)={0xffffffffffffffff, <r1=>0xffffffffffffffff}, 0x800)
mount$9p_fd(0x0, &(0x7f0000000040)='./file0\x00', &(0x7f00000000c0), 0x408, &(0x7f0000000280)={'trans=fd,', {'rfdno', 0x3d, r0}, 0x2c, {'wfdno', 0x3d, r1}, 0x2c, {[{@cache_loose}, {@mmap}, {@loose}, {@loose}, {@mmap}], [{@mask={'mask', 0x3d, '^MAY_EXEC'}}, {@fsmagic={'fsmagic', 0x3d, 0x10001}}, {@dont_hash}]}})
Sample report:
==================================================================
BUG: KASAN: use-after-free in kernfs_type include/linux/kernfs.h:335 [inline]
BUG: KASAN: use-after-free in kernfs_leftmost_descendant fs/kernfs/dir.c:1261 [inline]
BUG: KASAN: use-after-free in __kernfs_remove.part.0+0x843/0x960 fs/kernfs/dir.c:1369
Read of size 2 at addr ffff8880088807f0 by task syz-executor.2/857
CPU: 0 PID: 857 Comm: syz-executor.2 Not tainted 6.0.0-rc3-00363-g7726d4c3e60b #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x6e/0x91 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:317 [inline]
print_report.cold+0x5e/0x5e5 mm/kasan/report.c:433
kasan_report+0xa3/0x130 mm/kasan/report.c:495
kernfs_type include/linux/kernfs.h:335 [inline]
kernfs_leftmost_descendant fs/kernfs/dir.c:1261 [inline]
__kernfs_remove.part.0+0x843/0x960 fs/kernfs/dir.c:1369
__kernfs_remove fs/kernfs/dir.c:1356 [inline]
kernfs_remove_by_name_ns+0x108/0x190 fs/kernfs/dir.c:1589
sysfs_slab_add+0x133/0x1e0 mm/slub.c:5943
__kmem_cache_create+0x3e0/0x550 mm/slub.c:4899
create_cache mm/slab_common.c:229 [inline]
kmem_cache_create_usercopy+0x167/0x2a0 mm/slab_common.c:335
p9_client_create+0xd4d/0x1190 net/9p/client.c:993
v9fs_session_init+0x1e6/0x13c0 fs/9p/v9fs.c:408
v9fs_mount+0xb9/0xbd0 fs/9p/vfs_super.c:126
legacy_get_tree+0xf1/0x200 fs/fs_context.c:610
vfs_get_tree+0x85/0x2e0 fs/super.c:1530
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x675/0x1d00 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x282/0x300 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f725f983aed
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f725f0f7028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f725faa3f80 RCX: 00007f725f983aed
RDX: 00000000200000c0 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 00007f725f9f419c R08: 0000000020000280 R09: 0000000000000000
R10: 0000000000000408 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000006 R14: 00007f725faa3f80 R15: 00007f725f0d7000
</TASK>
Allocated by task 855:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:437 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:470
kasan_slab_alloc include/linux/kasan.h:224 [inline]
slab_post_alloc_hook mm/slab.h:7
---truncated---
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
scsi: libsas: Fix use-after-free bug in smp_execute_task_sg()
When executing SMP task failed, the smp_execute_task_sg() calls del_timer()
to delete "slow_task->timer". However, if the timer handler
sas_task_internal_timedout() is running, the del_timer() in
smp_execute_task_sg() will not stop it and a UAF will happen. The process
is shown below:
(thread 1) | (thread 2)
smp_execute_task_sg() | sas_task_internal_timedout()
... |
del_timer() |
... | ...
sas_free_task(task) |
kfree(task->slow_task) //FREE|
| task->slow_task->... //USE
Fix by calling del_timer_sync() in smp_execute_task_sg(), which makes sure
the timer handler have finished before the "task->slow_task" is
deallocated.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
ACPICA: Fix use-after-free in acpi_ut_copy_ipackage_to_ipackage()
There is an use-after-free reported by KASAN:
BUG: KASAN: use-after-free in acpi_ut_remove_reference+0x3b/0x82
Read of size 1 at addr ffff888112afc460 by task modprobe/2111
CPU: 0 PID: 2111 Comm: modprobe Not tainted 6.1.0-rc7-dirty
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
Call Trace:
<TASK>
kasan_report+0xae/0xe0
acpi_ut_remove_reference+0x3b/0x82
acpi_ut_copy_iobject_to_iobject+0x3be/0x3d5
acpi_ds_store_object_to_local+0x15d/0x3a0
acpi_ex_store+0x78d/0x7fd
acpi_ex_opcode_1A_1T_1R+0xbe4/0xf9b
acpi_ps_parse_aml+0x217/0x8d5
...
</TASK>
The root cause of the problem is that the acpi_operand_object
is freed when acpi_ut_walk_package_tree() fails in
acpi_ut_copy_ipackage_to_ipackage(), lead to repeated release in
acpi_ut_copy_iobject_to_iobject(). The problem was introduced
by "8aa5e56eeb61" commit, this commit is to fix memory leak in
acpi_ut_copy_iobject_to_iobject(), repeatedly adding remove
operation, lead to "acpi_operand_object" used after free.
Fix it by removing acpi_ut_remove_reference() in
acpi_ut_copy_ipackage_to_ipackage(). acpi_ut_copy_ipackage_to_ipackage()
is called to copy an internal package object into another internal
package object, when it fails, the memory of acpi_operand_object
should be freed by the caller.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix UBSAN shift-out-of-bounds warning
If get_num_sdma_queues or get_num_xgmi_sdma_queues is 0, we end up
doing a shift operation where the number of bits shifted equals
number of bits in the operand. This behaviour is undefined.
Set num_sdma_queues or num_xgmi_sdma_queues to ULLONG_MAX, if the
count is >= number of bits in the operand.
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1472
CVSS Score
7.1
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
ceph: fix race condition validating r_parent before applying state
Add validation to ensure the cached parent directory inode matches the
directory info in MDS replies. This prevents client-side race conditions
where concurrent operations (e.g. rename) cause r_parent to become stale
between request initiation and reply processing, which could lead to
applying state changes to incorrect directory inodes.
[ idryomov: folded a kerneldoc fixup and a follow-up fix from Alex to
move CEPH_CAP_PIN reference when r_parent is updated:
When the parent directory lock is not held, req->r_parent can become
stale and is updated to point to the correct inode. However, the
associated CEPH_CAP_PIN reference was not being adjusted. The
CEPH_CAP_PIN is a reference on an inode that is tracked for
accounting purposes. Moving this pin is important to keep the
accounting balanced. When the pin was not moved from the old parent
to the new one, it created two problems: The reference on the old,
stale parent was never released, causing a reference leak.
A reference for the new parent was never acquired, creating the risk
of a reference underflow later in ceph_mdsc_release_request(). This
patch corrects the logic by releasing the pin from the old parent and
acquiring it for the new parent when r_parent is switched. This
ensures reference accounting stays balanced. ]
CVSS Score
4.7
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
pcmcia: Add error handling for add_interval() in do_validate_mem()
In the do_validate_mem(), the call to add_interval() does not
handle errors. If kmalloc() fails in add_interval(), it could
result in a null pointer being inserted into the linked list,
leading to illegal memory access when sub_interval() is called
next.
This patch adds an error handling for the add_interval(). If
add_interval() returns an error, the function will return early
with the error code.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees
When we don't have a clock specified in the device tree, we have no way to
ensure the BAM is on. This is often the case for remotely-controlled or
remotely-powered BAM instances. In this case, we need to read num-channels
from the DT to have all the necessary information to complete probing.
However, at the moment invalid device trees without clock and without
num-channels still continue probing, because the error handling is missing
return statements. The driver will then later try to read the number of
channels from the registers. This is unsafe, because it relies on boot
firmware and lucky timing to succeed. Unfortunately, the lack of proper
error handling here has been abused for several Qualcomm SoCs upstream,
causing early boot crashes in several situations [1, 2].
Avoid these early crashes by erroring out when any of the required DT
properties are missing. Note that this will break some of the existing DTs
upstream (mainly BAM instances related to the crypto engine). However,
clearly these DTs have never been tested properly, since the error in the
kernel log was just ignored. It's safer to disable the crypto engine for
these broken DTBs.
[1]: https://lore.kernel.org/r/CY01EKQVWE36.B9X5TDXAREPF@fairphone.com/
[2]: https://lore.kernel.org/r/20230626145959.646747-1-krzysztof.kozlowski@linaro.org/
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
i40e: fix IRQ freeing in i40e_vsi_request_irq_msix error path
If request_irq() in i40e_vsi_request_irq_msix() fails in an iteration
later than the first, the error path wants to free the IRQs requested
so far. However, it uses the wrong dev_id argument for free_irq(), so
it does not free the IRQs correctly and instead triggers the warning:
Trying to free already-free IRQ 173
WARNING: CPU: 25 PID: 1091 at kernel/irq/manage.c:1829 __free_irq+0x192/0x2c0
Modules linked in: i40e(+) [...]
CPU: 25 UID: 0 PID: 1091 Comm: NetworkManager Not tainted 6.17.0-rc1+ #1 PREEMPT(lazy)
Hardware name: [...]
RIP: 0010:__free_irq+0x192/0x2c0
[...]
Call Trace:
<TASK>
free_irq+0x32/0x70
i40e_vsi_request_irq_msix.cold+0x63/0x8b [i40e]
i40e_vsi_request_irq+0x79/0x80 [i40e]
i40e_vsi_open+0x21f/0x2f0 [i40e]
i40e_open+0x63/0x130 [i40e]
__dev_open+0xfc/0x210
__dev_change_flags+0x1fc/0x240
netif_change_flags+0x27/0x70
do_setlink.isra.0+0x341/0xc70
rtnl_newlink+0x468/0x860
rtnetlink_rcv_msg+0x375/0x450
netlink_rcv_skb+0x5c/0x110
netlink_unicast+0x288/0x3c0
netlink_sendmsg+0x20d/0x430
____sys_sendmsg+0x3a2/0x3d0
___sys_sendmsg+0x99/0xe0
__sys_sendmsg+0x8a/0xf0
do_syscall_64+0x82/0x2c0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
[...]
</TASK>
---[ end trace 0000000000000000 ]---
Use the same dev_id for free_irq() as for request_irq().
I tested this with inserting code to fail intentionally.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.
syzbot reported the splat below. [0]
The repro does the following:
1. Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes)
2. Attach the prog to a SOCKMAP
3. Add a socket to the SOCKMAP
4. Activate fault injection
5. Send data less than cork_bytes
At 5., the data is carried over to the next sendmsg() as it is
smaller than the cork_bytes specified by bpf_msg_cork_bytes().
Then, tcp_bpf_send_verdict() tries to allocate psock->cork to hold
the data, but this fails silently due to fault injection + __GFP_NOWARN.
If the allocation fails, we need to revert the sk->sk_forward_alloc
change done by sk_msg_alloc().
Let's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate
psock->cork.
The "*copied" also needs to be updated such that a proper error can
be returned to the caller, sendmsg. It fails to allocate psock->cork.
Nothing has been corked so far, so this patch simply sets "*copied"
to 0.
[0]:
WARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983
Modules linked in:
CPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156
Code: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 <0f> 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc
RSP: 0018:ffffc90000a08b48 EFLAGS: 00010246
RAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80
RDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000
RBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4
R10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380
R13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872
FS: 00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0
Call Trace:
<IRQ>
__sk_destruct+0x86/0x660 net/core/sock.c:2339
rcu_do_batch kernel/rcu/tree.c:2605 [inline]
rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
</IRQ>
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
net: phylink: add lock for serializing concurrent pl->phydev writes with resolver
Currently phylink_resolve() protects itself against concurrent
phylink_bringup_phy() or phylink_disconnect_phy() calls which modify
pl->phydev by relying on pl->state_mutex.
The problem is that in phylink_resolve(), pl->state_mutex is in a lock
inversion state with pl->phydev->lock. So pl->phydev->lock needs to be
acquired prior to pl->state_mutex. But that requires dereferencing
pl->phydev in the first place, and without pl->state_mutex, that is
racy.
Hence the reason for the extra lock. Currently it is redundant, but it
will serve a functional purpose once mutex_lock(&phy->lock) will be
moved outside of the mutex_lock(&pl->state_mutex) section.
Another alternative considered would have been to let phylink_resolve()
acquire the rtnl_mutex, which is also held when phylink_bringup_phy()
and phylink_disconnect_phy() are called. But since phylink_disconnect_phy()
runs under rtnl_lock(), it would deadlock with phylink_resolve() when
calling flush_work(&pl->resolve). Additionally, it would have been
undesirable because it would have unnecessarily blocked many other call
paths as well in the entire kernel, so the smaller-scoped lock was
preferred.
CVSS Score
7.0
EPSS Score
0.0
Published
2025-10-01