Linux: >> Linux Kernel >> 6.1.137 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
f2fs: don't set RO when shutting down f2fs
Shutdown does not check the error of thaw_super due to readonly, which
causes a deadlock like below.
f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC) issue_discard_thread
- bdev_freeze
- freeze_super
- f2fs_stop_checkpoint()
- f2fs_handle_critical_error - sb_start_write
- set RO - waiting
- bdev_thaw
- thaw_super_locked
- return -EINVAL, if sb_rdonly()
- f2fs_stop_discard_thread
-> wait for kthread_stop(discard_thread);
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-12
In the Linux kernel, the following vulnerability has been resolved:
media: mtk-vcodec: potential null pointer deference in SCP
The return value of devm_kzalloc() needs to be checked to avoid
NULL pointer deference. This is similar to CVE-2022-3113.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-12
In the Linux kernel, the following vulnerability has been resolved:
iommu: Return right value in iommu_sva_bind_device()
iommu_sva_bind_device() should return either a sva bond handle or an
ERR_PTR value in error cases. Existing drivers (idxd and uacce) only
check the return value with IS_ERR(). This could potentially lead to
a kernel NULL pointer dereference issue if the function returns NULL
instead of an error pointer.
In reality, this doesn't cause any problems because iommu_sva_bind_device()
only returns NULL when the kernel is not configured with CONFIG_IOMMU_SVA.
In this case, iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) will
return an error, and the device drivers won't call iommu_sva_bind_device()
at all.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-12
In the Linux kernel, the following vulnerability has been resolved:
parisc: Try to fix random segmentation faults in package builds
PA-RISC systems with PA8800 and PA8900 processors have had problems
with random segmentation faults for many years. Systems with earlier
processors are much more stable.
Systems with PA8800 and PA8900 processors have a large L2 cache which
needs per page flushing for decent performance when a large range is
flushed. The combined cache in these systems is also more sensitive to
non-equivalent aliases than the caches in earlier systems.
The majority of random segmentation faults that I have looked at
appear to be memory corruption in memory allocated using mmap and
malloc.
My first attempt at fixing the random faults didn't work. On
reviewing the cache code, I realized that there were two issues
which the existing code didn't handle correctly. Both relate
to cache move-in. Another issue is that the present bit in PTEs
is racy.
1) PA-RISC caches have a mind of their own and they can speculatively
load data and instructions for a page as long as there is a entry in
the TLB for the page which allows move-in. TLBs are local to each
CPU. Thus, the TLB entry for a page must be purged before flushing
the page. This is particularly important on SMP systems.
In some of the flush routines, the flush routine would be called
and then the TLB entry would be purged. This was because the flush
routine needed the TLB entry to do the flush.
2) My initial approach to trying the fix the random faults was to
try and use flush_cache_page_if_present for all flush operations.
This actually made things worse and led to a couple of hardware
lockups. It finally dawned on me that some lines weren't being
flushed because the pte check code was racy. This resulted in
random inequivalent mappings to physical pages.
The __flush_cache_page tmpalias flush sets up its own TLB entry
and it doesn't need the existing TLB entry. As long as we can find
the pte pointer for the vm page, we can get the pfn and physical
address of the page. We can also purge the TLB entry for the page
before doing the flush. Further, __flush_cache_page uses a special
TLB entry that inhibits cache move-in.
When switching page mappings, we need to ensure that lines are
removed from the cache. It is not sufficient to just flush the
lines to memory as they may come back.
This made it clear that we needed to implement all the required
flush operations using tmpalias routines. This includes flushes
for user and kernel pages.
After modifying the code to use tmpalias flushes, it became clear
that the random segmentation faults were not fully resolved. The
frequency of faults was worse on systems with a 64 MB L2 (PA8900)
and systems with more CPUs (rp4440).
The warning that I added to flush_cache_page_if_present to detect
pages that couldn't be flushed triggered frequently on some systems.
Helge and I looked at the pages that couldn't be flushed and found
that the PTE was either cleared or for a swap page. Ignoring pages
that were swapped out seemed okay but pages with cleared PTEs seemed
problematic.
I looked at routines related to pte_clear and noticed ptep_clear_flush.
The default implementation just flushes the TLB entry. However, it was
obvious that on parisc we need to flush the cache page as well. If
we don't flush the cache page, stale lines will be left in the cache
and cause random corruption. Once a PTE is cleared, there is no way
to find the physical address associated with the PTE and flush the
associated page at a later time.
I implemented an updated change with a parisc specific version of
ptep_clear_flush. It fixed the random data corruption on Helge's rp4440
and rp3440, as well as on my c8000.
At this point, I realized that I could restore the code where we only
flush in flush_cache_page_if_present if the page has been accessed.
However, for this, we also need to flush the cache when the accessed
bit is cleared in
---truncated---
CVSS Score
6.3
EPSS Score
0.0
Published
2024-07-12
In the Linux kernel, the following vulnerability has been resolved:
io_uring/io-wq: Use set_bit() and test_bit() at worker->flags
Utilize set_bit() and test_bit() on worker->flags within io_uring/io-wq
to address potential data races.
The structure io_worker->flags may be accessed through various data
paths, leading to concurrency issues. When KCSAN is enabled, it reveals
data races occurring in io_worker_handle_work and
io_wq_activate_free_worker functions.
BUG: KCSAN: data-race in io_worker_handle_work / io_wq_activate_free_worker
write to 0xffff8885c4246404 of 4 bytes by task 49071 on cpu 28:
io_worker_handle_work (io_uring/io-wq.c:434 io_uring/io-wq.c:569)
io_wq_worker (io_uring/io-wq.c:?)
<snip>
read to 0xffff8885c4246404 of 4 bytes by task 49024 on cpu 5:
io_wq_activate_free_worker (io_uring/io-wq.c:? io_uring/io-wq.c:285)
io_wq_enqueue (io_uring/io-wq.c:947)
io_queue_iowq (io_uring/io_uring.c:524)
io_req_task_submit (io_uring/io_uring.c:1511)
io_handle_tw_list (io_uring/io_uring.c:1198)
<snip>
Line numbers against commit 18daea77cca6 ("Merge tag 'for-linus' of
git://git.kernel.org/pub/scm/virt/kvm/kvm").
These races involve writes and reads to the same memory location by
different tasks running on different CPUs. To mitigate this, refactor
the code to use atomic operations such as set_bit(), test_bit(), and
clear_bit() instead of basic "and" and "or" operations. This ensures
thread-safe manipulation of worker flags.
Also, move `create_index` to avoid holes in the structure.
CVSS Score
4.7
EPSS Score
0.0
Published
2024-07-12
In the Linux kernel, the following vulnerability has been resolved:
xfs: fix log recovery buffer allocation for the legacy h_size fixup
Commit a70f9fe52daa ("xfs: detect and handle invalid iclog size set by
mkfs") added a fixup for incorrect h_size values used for the initial
umount record in old xfsprogs versions. Later commit 0c771b99d6c9
("xfs: clean up calculation of LR header blocks") cleaned up the log
reover buffer calculation, but stoped using the fixed up h_size value
to size the log recovery buffer, which can lead to an out of bounds
access when the incorrect h_size does not come from the old mkfs
tool, but a fuzzer.
Fix this by open coding xlog_logrec_hblks and taking the fixed h_size
into account for this calculation.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-05
In the Linux kernel, the following vulnerability has been resolved:
ASoC: SOF: ipc4-topology: Fix input format query of process modules without base extension
If a process module does not have base config extension then the same
format applies to all of it's inputs and the process->base_config_ext is
NULL, causing NULL dereference when specifically crafted topology and
sequences used.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-05
In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: WARN on vNMI + NMI window iff NMIs are outright masked
When requesting an NMI window, WARN on vNMI support being enabled if and
only if NMIs are actually masked, i.e. if the vCPU is already handling an
NMI. KVM's ABI for NMIs that arrive simultanesouly (from KVM's point of
view) is to inject one NMI and pend the other. When using vNMI, KVM pends
the second NMI simply by setting V_NMI_PENDING, and lets the CPU do the
rest (hardware automatically sets V_NMI_BLOCKING when an NMI is injected).
However, if KVM can't immediately inject an NMI, e.g. because the vCPU is
in an STI shadow or is running with GIF=0, then KVM will request an NMI
window and trigger the WARN (but still function correctly).
Whether or not the GIF=0 case makes sense is debatable, as the intent of
KVM's behavior is to provide functionality that is as close to real
hardware as possible. E.g. if two NMIs are sent in quick succession, the
probability of both NMIs arriving in an STI shadow is infinitesimally low
on real hardware, but significantly larger in a virtual environment, e.g.
if the vCPU is preempted in the STI shadow. For GIF=0, the argument isn't
as clear cut, because the window where two NMIs can collide is much larger
in bare metal (though still small).
That said, KVM should not have divergent behavior for the GIF=0 case based
on whether or not vNMI support is enabled. And KVM has allowed
simultaneous NMIs with GIF=0 for over a decade, since commit 7460fb4a3400
("KVM: Fix simultaneous NMIs"). I.e. KVM's GIF=0 handling shouldn't be
modified without a *really* good reason to do so, and if KVM's behavior
were to be modified, it should be done irrespective of vNMI support.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-05
In the Linux kernel, the following vulnerability has been resolved:
media: v4l: async: Properly re-initialise notifier entry in unregister
The notifier_entry of a notifier is not re-initialised after unregistering
the notifier. This leads to dangling pointers being left there so use
list_del_init() to return the notifier_entry an empty list.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-05
The IPv6 implementation in the Linux kernel before 6.3 has a net/ipv6/route.c max_size threshold that can be consumed easily, e.g., leading to a denial of service (network is unreachable errors) when IPv6 packets are sent in a loop via a raw socket.
CVSS Score
7.5
EPSS Score
0.001
Published
2024-07-05