Linux: >> Linux Kernel >> 6.6.48 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
hwpoison, memory_hotplug: lock folio before unmap hwpoisoned folio
Commit b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to
be offlined) add page poison checks in do_migrate_range in order to make
offline hwpoisoned page possible by introducing isolate_lru_page and
try_to_unmap for hwpoisoned page. However folio lock must be held before
calling try_to_unmap. Add it to fix this problem.
Warning will be produced if folio is not locked during unmap:
------------[ cut here ]------------
kernel BUG at ./include/linux/swapops.h:400!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 4 UID: 0 PID: 411 Comm: bash Tainted: G W 6.13.0-rc1-00016-g3c434c7ee82a-dirty #41
Tainted: [W]=WARN
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : try_to_unmap_one+0xb08/0xd3c
lr : try_to_unmap_one+0x3dc/0xd3c
Call trace:
try_to_unmap_one+0xb08/0xd3c (P)
try_to_unmap_one+0x3dc/0xd3c (L)
rmap_walk_anon+0xdc/0x1f8
rmap_walk+0x3c/0x58
try_to_unmap+0x88/0x90
unmap_poisoned_folio+0x30/0xa8
do_migrate_range+0x4a0/0x568
offline_pages+0x5a4/0x670
memory_block_action+0x17c/0x374
memory_subsys_offline+0x3c/0x78
device_offline+0xa4/0xd0
state_store+0x8c/0xf0
dev_attr_store+0x18/0x2c
sysfs_kf_write+0x44/0x54
kernfs_fop_write_iter+0x118/0x1a8
vfs_write+0x3a8/0x4bc
ksys_write+0x6c/0xf8
__arm64_sys_write+0x1c/0x28
invoke_syscall+0x44/0x100
el0_svc_common.constprop.0+0x40/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x30/0xd0
el0t_64_sync_handler+0xc8/0xcc
el0t_64_sync+0x198/0x19c
Code: f9407be0 b5fff320 d4210000 17ffff97 (d4210000)
---[ end trace 0000000000000000 ]---
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
cdx: Fix possible UAF error in driver_override_show()
Fixed a possible UAF problem in driver_override_show() in drivers/cdx/cdx.c
This function driver_override_show() is part of DEVICE_ATTR_RW, which
includes both driver_override_show() and driver_override_store().
These functions can be executed concurrently in sysfs.
The driver_override_store() function uses driver_set_override() to
update the driver_override value, and driver_set_override() internally
locks the device (device_lock(dev)). If driver_override_show() reads
cdx_dev->driver_override without locking, it could potentially access
a freed pointer if driver_override_store() frees the string
concurrently. This could lead to printing a kernel address, which is a
security risk since DEVICE_ATTR can be read by all users.
Additionally, a similar pattern is used in drivers/amba/bus.c, as well
as many other bus drivers, where device_lock() is taken in the show
function, and it has been working without issues.
This potential bug was detected by our experimental static analysis
tool, which analyzes locking APIs and paired functions to identify
data races and atomicity violations.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
usb: atm: cxacru: fix a flaw in existing endpoint checks
Syzbot once again identified a flaw in usb endpoint checking, see [1].
This time the issue stems from a commit authored by me (2eabb655a968
("usb: atm: cxacru: fix endpoint checking in cxacru_bind()")).
While using usb_find_common_endpoints() may usually be enough to
discard devices with wrong endpoints, in this case one needs more
than just finding and identifying the sufficient number of endpoints
of correct types - one needs to check the endpoint's address as well.
Since cxacru_bind() fills URBs with CXACRU_EP_CMD address in mind,
switch the endpoint verification approach to usb_check_XXX_endpoints()
instead to fix incomplete ep testing.
[1] Syzbot report:
usb 5-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 1378 at drivers/usb/core/urb.c:504 usb_submit_urb+0xc4e/0x18c0 drivers/usb/core/urb.c:503
...
RIP: 0010:usb_submit_urb+0xc4e/0x18c0 drivers/usb/core/urb.c:503
...
Call Trace:
<TASK>
cxacru_cm+0x3c8/0xe50 drivers/usb/atm/cxacru.c:649
cxacru_card_status drivers/usb/atm/cxacru.c:760 [inline]
cxacru_bind+0xcf9/0x1150 drivers/usb/atm/cxacru.c:1223
usbatm_usb_probe+0x314/0x1d30 drivers/usb/atm/usbatm.c:1058
cxacru_usb_probe+0x184/0x220 drivers/usb/atm/cxacru.c:1377
usb_probe_interface+0x641/0xbb0 drivers/usb/core/driver.c:396
really_probe+0x2b9/0xad0 drivers/base/dd.c:658
__driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
driver_probe_device+0x50/0x430 drivers/base/dd.c:830
...
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
usb: renesas_usbhs: Flush the notify_hotplug_work
When performing continuous unbind/bind operations on the USB drivers
available on the Renesas RZ/G2L SoC, a kernel crash with the message
"Unable to handle kernel NULL pointer dereference at virtual address"
may occur. This issue points to the usbhsc_notify_hotplug() function.
Flush the delayed work to avoid its execution when driver resources are
unavailable.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
usb: typec: ucsi: Fix NULL pointer access
Resources should be released only after all threads that utilize them
have been destroyed.
This commit ensures that resources are not released prematurely by waiting
for the associated workqueue to complete before deallocating them.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
sched/fair: Fix potential memory corruption in child_cfs_rq_on_list
child_cfs_rq_on_list attempts to convert a 'prev' pointer to a cfs_rq.
This 'prev' pointer can originate from struct rq's leaf_cfs_rq_list,
making the conversion invalid and potentially leading to memory
corruption. Depending on the relative positions of leaf_cfs_rq_list and
the task group (tg) pointer within the struct, this can cause a memory
fault or access garbage data.
The issue arises in list_add_leaf_cfs_rq, where both
cfs_rq->leaf_cfs_rq_list and rq->leaf_cfs_rq_list are added to the same
leaf list. Also, rq->tmp_alone_branch can be set to rq->leaf_cfs_rq_list.
This adds a check `if (prev == &rq->leaf_cfs_rq_list)` after the main
conditional in child_cfs_rq_on_list. This ensures that the container_of
operation will convert a correct cfs_rq struct.
This check is sufficient because only cfs_rqs on the same CPU are added
to the list, so verifying the 'prev' pointer against the current rq's list
head is enough.
Fixes a potential memory corruption issue that due to current struct
layout might not be manifesting as a crash but could lead to unpredictable
behavior when the layout changes.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
vlan: enforce underlying device type
Currently, VLAN devices can be created on top of non-ethernet devices.
Besides the fact that it doesn't make much sense, this also causes a
bug which leaks the address of a kernel function to usermode.
When creating a VLAN device, we initialize GARP (garp_init_applicant)
and MRP (mrp_init_applicant) for the underlying device.
As part of the initialization process, we add the multicast address of
each applicant to the underlying device, by calling dev_mc_add.
__dev_mc_add uses dev->addr_len to determine the length of the new
multicast address.
This causes an out-of-bounds read if dev->addr_len is greater than 6,
since the multicast addresses provided by GARP and MRP are only 6
bytes long.
This behaviour can be reproduced using the following commands:
ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo
ip l set up dev gretest
ip link add link gretest name vlantest type vlan id 100
Then, the following command will display the address of garp_pdu_rcv:
ip maddr show | grep 01:80:c2:00:00:21
Fix the bug by enforcing the type of the underlying device during VLAN
device initialization.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
ppp: Fix KMSAN uninit-value warning with bpf
Syzbot caught an "KMSAN: uninit-value" warning [1], which is caused by the
ppp driver not initializing a 2-byte header when using socket filter.
The following code can generate a PPP filter BPF program:
'''
struct bpf_program fp;
pcap_t *handle;
handle = pcap_open_dead(DLT_PPP_PPPD, 65535);
pcap_compile(handle, &fp, "ip and outbound", 0, 0);
bpf_dump(&fp, 1);
'''
Its output is:
'''
(000) ldh [2]
(001) jeq #0x21 jt 2 jf 5
(002) ldb [0]
(003) jeq #0x1 jt 4 jf 5
(004) ret #65535
(005) ret #0
'''
Wen can find similar code at the following link:
https://github.com/ppp-project/ppp/blob/master/pppd/options.c#L1680
The maintainer of this code repository is also the original maintainer
of the ppp driver.
As you can see the BPF program skips 2 bytes of data and then reads the
'Protocol' field to determine if it's an IP packet. Then it read the first
byte of the first 2 bytes to determine the direction.
The issue is that only the first byte indicating direction is initialized
in current ppp driver code while the second byte is not initialized.
For normal BPF programs generated by libpcap, uninitialized data won't be
used, so it's not a problem. However, for carefully crafted BPF programs,
such as those generated by syzkaller [2], which start reading from offset
0, the uninitialized data will be used and caught by KMSAN.
[1] https://syzkaller.appspot.com/bug?extid=853242d9c9917165d791
[2] https://syzkaller.appspot.com/text?tag=ReproC&x=11994913980000
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
mm: memory-failure: update ttu flag inside unmap_poisoned_folio
Patch series "mm: memory_failure: unmap poisoned folio during migrate
properly", v3.
Fix two bugs during folio migration if the folio is poisoned.
This patch (of 3):
Commit 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to
TTU_HWPOISON") introduce TTU_HWPOISON to replace TTU_IGNORE_HWPOISON in
order to stop send SIGBUS signal when accessing an error page after a
memory error on a clean folio. However during page migration, anon folio
must be set with TTU_HWPOISON during unmap_*(). For pagecache we need
some policy just like the one in hwpoison_user_mappings to set this flag.
So move this policy from hwpoison_user_mappings to unmap_poisoned_folio to
handle this warning properly.
Warning will be produced during unamp poison folio with the following log:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 365 at mm/rmap.c:1847 try_to_unmap_one+0x8fc/0xd3c
Modules linked in:
CPU: 1 UID: 0 PID: 365 Comm: bash Tainted: G W 6.13.0-rc1-00018-gacdb4bbda7ab #42
Tainted: [W]=WARN
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : try_to_unmap_one+0x8fc/0xd3c
lr : try_to_unmap_one+0x3dc/0xd3c
Call trace:
try_to_unmap_one+0x8fc/0xd3c (P)
try_to_unmap_one+0x3dc/0xd3c (L)
rmap_walk_anon+0xdc/0x1f8
rmap_walk+0x3c/0x58
try_to_unmap+0x88/0x90
unmap_poisoned_folio+0x30/0xa8
do_migrate_range+0x4a0/0x568
offline_pages+0x5a4/0x670
memory_block_action+0x17c/0x374
memory_subsys_offline+0x3c/0x78
device_offline+0xa4/0xd0
state_store+0x8c/0xf0
dev_attr_store+0x18/0x2c
sysfs_kf_write+0x44/0x54
kernfs_fop_write_iter+0x118/0x1a8
vfs_write+0x3a8/0x4bc
ksys_write+0x6c/0xf8
__arm64_sys_write+0x1c/0x28
invoke_syscall+0x44/0x100
el0_svc_common.constprop.0+0x40/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x30/0xd0
el0t_64_sync_handler+0xc8/0xcc
el0t_64_sync+0x198/0x19c
---[ end trace 0000000000000000 ]---
[mawupeng1@huawei.com: unmap_poisoned_folio(): remove shadowed local `mapping', per Miaohe]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01
In the Linux kernel, the following vulnerability has been resolved:
NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback
Add PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so
nfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.
Otherwise NFS can deadlock waiting for kcompactd enduced writeback which
recurses back to NFS (which triggers writeback to NFSD via NFS loopback
mount on the same host, NFSD blocks waiting for XFS's call to
__filemap_get_folio):
6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.
{---
[58] "kcompactd0"
[<0>] folio_wait_bit+0xe8/0x200
[<0>] folio_wait_writeback+0x2b/0x80
[<0>] nfs_wb_folio+0x80/0x1b0 [nfs]
[<0>] nfs_release_folio+0x68/0x130 [nfs]
[<0>] split_huge_page_to_list_to_order+0x362/0x840
[<0>] migrate_pages_batch+0x43d/0xb90
[<0>] migrate_pages_sync+0x9a/0x240
[<0>] migrate_pages+0x93c/0x9f0
[<0>] compact_zone+0x8e2/0x1030
[<0>] compact_node+0xdb/0x120
[<0>] kcompactd+0x121/0x2e0
[<0>] kthread+0xcf/0x100
[<0>] ret_from_fork+0x31/0x40
[<0>] ret_from_fork_asm+0x1a/0x30
---}
[akpm@linux-foundation.org: fix build]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-01