Linux: >> Linux Kernel >> 2.6.35.7 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm: avoid overflows in dirty throttling logic
The dirty throttling logic is interspersed with assumptions that dirty
limits in PAGE_SIZE units fit into 32-bit (so that various multiplications
fit into 64-bits). If limits end up being larger, we will hit overflows,
possible divisions by 0 etc. Fix these problems by never allowing so
large dirty limits as they have dubious practical value anyway. For
dirty_bytes / dirty_background_bytes interfaces we can just refuse to set
so large limits. For dirty_ratio / dirty_background_ratio it isn't so
simple as the dirty limit is computed from the amount of available memory
which can change due to memory hotplug etc. So when converting dirty
limits from ratios to numbers of pages, we just don't allow the result to
exceed UINT_MAX.
This is root-only triggerable problem which occurs when the operator
sets dirty limits to >16 TB.
CVSS Score
4.4
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
virtio-pci: Check if is_avq is NULL
[bug]
In the virtio_pci_common.c function vp_del_vqs, vp_dev->is_avq is involved
to determine whether it is admin virtqueue, but this function vp_dev->is_avq
may be empty. For installations, virtio_pci_legacy does not assign a value
to vp_dev->is_avq.
[fix]
Check whether it is vp_dev->is_avq before use.
[test]
Test with virsh Attach device
Before this patch, the following command would crash the guest system
After applying the patch, everything seems to be working fine.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
vhost_task: Handle SIGKILL by flushing work and exiting
Instead of lingering until the device is closed, this has us handle
SIGKILL by:
1. marking the worker as killed so we no longer try to use it with
new virtqueues and new flush operations.
2. setting the virtqueue to worker mapping so no new works are queued.
3. running all the exiting works.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
cdrom: rearrange last_media_change check to avoid unintentional overflow
When running syzkaller with the newly reintroduced signed integer wrap
sanitizer we encounter this splat:
[ 366.015950] UBSAN: signed-integer-overflow in ../drivers/cdrom/cdrom.c:2361:33
[ 366.021089] -9223372036854775808 - 346321 cannot be represented in type '__s64' (aka 'long long')
[ 366.025894] program syz-executor.4 is using a deprecated SCSI ioctl, please convert it to SG_IO
[ 366.027502] CPU: 5 PID: 28472 Comm: syz-executor.7 Not tainted 6.8.0-rc2-00035-gb3ef86b5a957 #1
[ 366.027512] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 366.027518] Call Trace:
[ 366.027523] <TASK>
[ 366.027533] dump_stack_lvl+0x93/0xd0
[ 366.027899] handle_overflow+0x171/0x1b0
[ 366.038787] ata1.00: invalid multi_count 32 ignored
[ 366.043924] cdrom_ioctl+0x2c3f/0x2d10
[ 366.063932] ? __pm_runtime_resume+0xe6/0x130
[ 366.071923] sr_block_ioctl+0x15d/0x1d0
[ 366.074624] ? __pfx_sr_block_ioctl+0x10/0x10
[ 366.077642] blkdev_ioctl+0x419/0x500
[ 366.080231] ? __pfx_blkdev_ioctl+0x10/0x10
...
Historically, the signed integer overflow sanitizer did not work in the
kernel due to its interaction with `-fwrapv` but this has since been
changed [1] in the newest version of Clang. It was re-enabled in the
kernel with Commit 557f8c582a9ba8ab ("ubsan: Reintroduce signed overflow
sanitizer").
Let's rearrange the check to not perform any arithmetic, thus not
tripping the sanitizer.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Add NULL pointer check for kzalloc
[Why & How]
Check return pointer of kzalloc before using it.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix double free err_addr pointer warnings
In amdgpu_umc_bad_page_polling_timeout, the amdgpu_umc_handle_bad_pages
will be run many times so that double free err_addr in some special case.
So set the err_addr to NULL to avoid the warnings.
CVSS Score
4.4
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: fix null pointer dereference in nouveau_connector_get_modes
In nouveau_connector_get_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a possible NULL pointer
dereference on failure of drm_mode_duplicate(). Add a check to avoid npd.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: add missing check for inode numbers on directory entries
Syzbot reported that mounting and unmounting a specific pattern of
corrupted nilfs2 filesystem images causes a use-after-free of metadata
file inodes, which triggers a kernel bug in lru_add_fn().
As Jan Kara pointed out, this is because the link count of a metadata file
gets corrupted to 0, and nilfs_evict_inode(), which is called from iput(),
tries to delete that inode (ifile inode in this case).
The inconsistency occurs because directories containing the inode numbers
of these metadata files that should not be visible in the namespace are
read without checking.
Fix this issue by treating the inode numbers of these internal files as
errors in the sanity check helper when reading directory folios/pages.
Also thanks to Hillf Danton and Matthew Wilcox for their initial mm-layer
analysis.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-07-30
In the Linux kernel, the following vulnerability has been resolved:
x86: stop playing stack games in profile_pc()
The 'profile_pc()' function is used for timer-based profiling, which
isn't really all that relevant any more to begin with, but it also ends
up making assumptions based on the stack layout that aren't necessarily
valid.
Basically, the code tries to account the time spent in spinlocks to the
caller rather than the spinlock, and while I support that as a concept,
it's not worth the code complexity or the KASAN warnings when no serious
profiling is done using timers anyway these days.
And the code really does depend on stack layout that is only true in the
simplest of cases. We've lost the comment at some point (I think when
the 32-bit and 64-bit code was unified), but it used to say:
Assume the lock function has either no stack frame or a copy
of eflags from PUSHF.
which explains why it just blindly loads a word or two straight off the
stack pointer and then takes a minimal look at the values to just check
if they might be eflags or the return pc:
Eflags always has bits 22 and up cleared unlike kernel addresses
but that basic stack layout assumption assumes that there isn't any lock
debugging etc going on that would complicate the code and cause a stack
frame.
It causes KASAN unhappiness reported for years by syzkaller [1] and
others [2].
With no real practical reason for this any more, just remove the code.
Just for historical interest, here's some background commits relating to
this code from 2006:
0cb91a229364 ("i386: Account spinlocks to the caller during profiling for !FP kernels")
31679f38d886 ("Simplify profile_pc on x86-64")
and a code unification from 2009:
ef4512882dbe ("x86: time_32/64.c unify profile_pc")
but the basics of this thing actually goes back to before the git tree.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
net/dpaa2: Avoid explicit cpumask var allocation on stack
For CONFIG_CPUMASK_OFFSTACK=y kernel, explicit allocation of cpumask
variable on stack is not recommended since it can cause potential stack
overflow.
Instead, kernel code should always use *cpumask_var API(s) to allocate
cpumask var in config-neutral way, leaving allocation strategy to
CONFIG_CPUMASK_OFFSTACK.
Use *cpumask_var API(s) to address it.
CVSS Score
7.3
EPSS Score
0.0
Published
2024-07-29