Linux: >> Linux Kernel >> 6.0.11 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
pnode: terminate at peers of source
The propagate_mnt() function handles mount propagation when creating
mounts and propagates the source mount tree @source_mnt to all
applicable nodes of the destination propagation mount tree headed by
@dest_mnt.
Unfortunately it contains a bug where it fails to terminate at peers of
@source_mnt when looking up copies of the source mount that become
masters for copies of the source mount tree mounted on top of slaves in
the destination propagation tree causing a NULL dereference.
Once the mechanics of the bug are understood it's easy to trigger.
Because of unprivileged user namespaces it is available to unprivileged
users.
While fixing this bug we've gotten confused multiple times due to
unclear terminology or missing concepts. So let's start this with some
clarifications:
* The terms "master" or "peer" denote a shared mount. A shared mount
belongs to a peer group.
* A peer group is a set of shared mounts that propagate to each other.
They are identified by a peer group id. The peer group id is available
in @shared_mnt->mnt_group_id.
Shared mounts within the same peer group have the same peer group id.
The peers in a peer group can be reached via @shared_mnt->mnt_share.
* The terms "slave mount" or "dependent mount" denote a mount that
receives propagation from a peer in a peer group. IOW, shared mounts
may have slave mounts and slave mounts have shared mounts as their
master. Slave mounts of a given peer in a peer group are listed on
that peers slave list available at @shared_mnt->mnt_slave_list.
* The term "master mount" denotes a mount in a peer group. IOW, it
denotes a shared mount or a peer mount in a peer group. The term
"master mount" - or "master" for short - is mostly used when talking
in the context of slave mounts that receive propagation from a master
mount. A master mount of a slave identifies the closest peer group a
slave mount receives propagation from. The master mount of a slave can
be identified via @slave_mount->mnt_master. Different slaves may point
to different masters in the same peer group.
* Multiple peers in a peer group can have non-empty ->mnt_slave_lists.
Non-empty ->mnt_slave_lists of peers don't intersect. Consequently, to
ensure all slave mounts of a peer group are visited the
->mnt_slave_lists of all peers in a peer group have to be walked.
* Slave mounts point to a peer in the closest peer group they receive
propagation from via @slave_mnt->mnt_master (see above). Together with
these peers they form a propagation group (see below). The closest
peer group can thus be identified through the peer group id
@slave_mnt->mnt_master->mnt_group_id of the peer/master that a slave
mount receives propagation from.
* A shared-slave mount is a slave mount to a peer group pg1 while also
a peer in another peer group pg2. IOW, a peer group may receive
propagation from another peer group.
If a peer group pg1 is a slave to another peer group pg2 then all
peers in peer group pg1 point to the same peer in peer group pg2 via
->mnt_master. IOW, all peers in peer group pg1 appear on the same
->mnt_slave_list. IOW, they cannot be slaves to different peer groups.
* A pure slave mount is a slave mount that is a slave to a peer group
but is not a peer in another peer group.
* A propagation group denotes the set of mounts consisting of a single
peer group pg1 and all slave mounts and shared-slave mounts that point
to a peer in that peer group via ->mnt_master. IOW, all slave mounts
such that @slave_mnt->mnt_master->mnt_group_id is equal to
@shared_mnt->mnt_group_id.
The concept of a propagation group makes it easier to talk about a
single propagation level in a propagation tree.
For example, in propagate_mnt() the immediate peers of @dest_mnt and
all slaves of @dest_mnt's peer group form a propagation group pr
---truncated---
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
chardev: fix error handling in cdev_device_add()
While doing fault injection test, I got the following report:
------------[ cut here ]------------
kobject: '(null)' (0000000039956980): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 3 PID: 6306 at kobject_put+0x23d/0x4e0
CPU: 3 PID: 6306 Comm: 283 Tainted: G W 6.1.0-rc2-00005-g307c1086d7c9 #1253
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:kobject_put+0x23d/0x4e0
Call Trace:
<TASK>
cdev_device_add+0x15e/0x1b0
__iio_device_register+0x13b4/0x1af0 [industrialio]
__devm_iio_device_register+0x22/0x90 [industrialio]
max517_probe+0x3d8/0x6b4 [max517]
i2c_device_probe+0xa81/0xc00
When device_add() is injected fault and returns error, if dev->devt is not set,
cdev_add() is not called, cdev_del() is not needed. Fix this by checking dev->devt
in error path.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
ipc: fix memory leak in init_mqueue_fs()
When setup_mq_sysctls() failed in init_mqueue_fs(), mqueue_inode_cachep is
not released. In order to fix this issue, the release path is reordered.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix delayed allocation bug in ext4_clu_mapped for bigalloc + inline
When converting files with inline data to extents, delayed allocations
made on a file system created with both the bigalloc and inline options
can result in invalid extent status cache content, incorrect reserved
cluster counts, kernel memory leaks, and potential kernel panics.
With bigalloc, the code that determines whether a block must be
delayed allocated searches the extent tree to see if that block maps
to a previously allocated cluster. If not, the block is delayed
allocated, and otherwise, it isn't. However, if the inline option is
also used, and if the file containing the block is marked as able to
store data inline, there isn't a valid extent tree associated with
the file. The current code in ext4_clu_mapped() calls
ext4_find_extent() to search the non-existent tree for a previously
allocated cluster anyway, which typically finds nothing, as desired.
However, a side effect of the search can be to cache invalid content
from the non-existent tree (garbage) in the extent status tree,
including bogus entries in the pending reservation tree.
To fix this, avoid searching the extent tree when allocating blocks
for bigalloc + inline files that are being converted from inline to
extent mapped.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/bios: fix a memory leak in generate_lfp_data_ptrs
When (size != 0 || ptrs->lvds_ entries != 3), the program tries to
free() the ptrs. However, the ptrs is not created by calling kzmalloc(),
but is obtained by pointer offset operation.
This may lead to memory leaks or undefined behavior.
Fix this by replacing the arguments of kfree() with ptrs_block.
(cherry picked from commit 7674cd0b7d28b952151c3df26bbfa7e07eb2b4ec)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()
Wei Chen reports a kernel bug as blew:
general protection fault, probably for non-canonical address
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
...
Call Trace:
<TASK>
__i2c_transfer+0x77e/0x1930 drivers/i2c/i2c-core-base.c:2109
i2c_transfer+0x1d5/0x3d0 drivers/i2c/i2c-core-base.c:2170
i2cdev_ioctl_rdwr+0x393/0x660 drivers/i2c/i2c-dev.c:297
i2cdev_ioctl+0x75d/0x9f0 drivers/i2c/i2c-dev.c:458
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd834a8bded
In az6027_i2c_xfer(), if msg[i].addr is 0x99,
a null-ptr-deref will caused when accessing msg[i].buf.
For msg[i].len is 0 and msg[i].buf is null.
Fix this by checking msg[i].len in az6027_i2c_xfer().
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
media: dvbdev: adopts refcnt to avoid UAF
dvb_unregister_device() is known that prone to use-after-free.
That is, the cleanup from dvb_unregister_device() releases the dvb_device
even if there are pointers stored in file->private_data still refer to it.
This patch adds a reference counter into struct dvb_device and delays its
deallocation until no pointer refers to the object.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
drm/radeon: Add the missed acpi_put_table() to fix memory leak
When the radeon driver reads the bios information from ACPI
table in radeon_acpi_vfct_bios(), it misses to call acpi_put_table()
to release the ACPI memory after the init, so add acpi_put_table()
properly to fix the memory leak.
v2: fix text formatting (Alex)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
power: supply: fix null pointer dereferencing in power_supply_get_battery_info
when kmalloc() fail to allocate memory in kasprintf(), propname
will be NULL, strcmp() called by of_get_property() will cause
null pointer dereference.
So return ENOMEM if kasprintf() return NULL pointer.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
ext4: don't allow journal inode to have encrypt flag
Mounting a filesystem whose journal inode has the encrypt flag causes a
NULL dereference in fscrypt_limit_io_blocks() when the 'inlinecrypt'
mount option is used.
The problem is that when jbd2_journal_init_inode() calls bmap(), it
eventually finds its way into ext4_iomap_begin(), which calls
fscrypt_limit_io_blocks(). fscrypt_limit_io_blocks() requires that if
the inode is encrypted, then its encryption key must already be set up.
That's not the case here, since the journal inode is never "opened" like
a normal file would be. Hence the crash.
A reproducer is:
mkfs.ext4 -F /dev/vdb
debugfs -w /dev/vdb -R "set_inode_field <8> flags 0x80808"
mount /dev/vdb /mnt -o inlinecrypt
To fix this, make ext4 consider journal inodes with the encrypt flag to
be invalid. (Note, maybe other flags should be rejected on the journal
inode too. For now, this is just the minimal fix for the above issue.)
I've marked this as fixing the commit that introduced the call to
fscrypt_limit_io_blocks(), since that's what made an actual crash start
being possible. But this fix could be applied to any version of ext4
that supports the encrypt feature.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15