In the Linux kernel, the following vulnerability has been resolved:
gpio: shared: fix deadlock on shared proxy's parent removal
Commit 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set")
used the mutex embedded in struct gpio_shared_entry to protect the
offset field which now can be modified after assignment. The critical
section however is too wide and introduced a potential deadlock on the
removal of the shared GPIO proxy's parent.
Make the critical section shorter - only protect the offset when it's
being read.
While at it: mention the fact that the entry lock is now also used to
protect against concurrent access to the offset field in the structure's
documentation.
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()
DAMON sysfs maintains the DAMOS tried region directory objects via a
linked list. When the user requests refresh of the directories, DAMON
sysfs removes all the region directories first, and then generate updated
regions directory on the empty space. The removal function
(damon_sysfs_scheme_regions_rm_dirs()) only puts the kobj objects.
Deletion of the container region object from the linked list is done
inside the kobj release callback function.
If somehow the callback invocation is delayed, the list will contain
regions list that gonna be freed. If the updated region directories
creation is started in this situation, the list can be corrupted and
use-after-free can happen.
Because the kobj objects are managed by only DAMON sysfs, the issue cannot
happen in normal situation. But, such delays can be made on kernels that
built with CONFIG_DEBUG_KOBJECT_RELEASE. On the kernel, the issue can
indeed be reproduced like below.
# damo start --damos_action stat
# cd /sys/kernel/mm/damon/admin/kdamonds/0/
# for i in {1..10}; do echo update_schemes_tried_regions > state; done
# dmesg | grep underflow
[ 89.296152] refcount_t: underflow; use-after-free.
Fix the issue by removing the region object from the list when
decrementing the reference count.
Also update damos_sysfs_populate_region_dir() to add the region object to
the list only after the kobject_init_and_add() is success, so that fail of
kobject_init_and_add() is not leaving the deallocated object on the list.
The issue was discovered [1] by Sashiko.
In the Linux kernel, the following vulnerability has been resolved:
media: rc: igorplugusb: fix control request setup packet
Commit eac69475b01f ("media: rc: igorplugusb: heed coherency
rules") changed the control request storage from an embedded struct to
an allocated pointer so it can obey DMA coherency rules.
However, the driver still passes &ir->request to usb_fill_control_urb().
That points the URB setup packet at the pointer field itself rather than
at the allocated struct usb_ctrlrequest.
USB core then interprets pointer bytes as the setup packet. This can
produce an invalid bRequestType and trigger the control direction warning
reported by syzbot:
usb 2-1: BOGUS control dir, pipe 80003580 doesn't match bRequestType 0
Pass ir->request itself as the setup packet.
In the Linux kernel, the following vulnerability has been resolved:
gpio: rockchip: teardown bugs and resource leaks
Address several teardown issues and resource leaks in the driver's remove
path and error handling:
1. Debounce clock reference leak: The debounce clock (bank->db_clk) is
obtained using of_clk_get() which increments the clock's reference
count, but clk_put() is never called. Register a devm action to
cleanly release it on unbind. Note that of_clk_get(..., 1) remains
necessary over devm_clk_get() because the DT binding does not define
clock-names, precluding name-based lookup.
2. Unregistered chained IRQ handler: The chained IRQ handler is not
disconnected in remove(). If a stray interrupt fires after the driver
is removed, the kernel attempts to execute a stale handler, leading
to a panic. Fix this by clearing the handler in remove().
3. IRQ domain leak: The linear IRQ domain and its generic chips are
allocated manually during probe but never removed. Remove the IRQ
domain during driver teardown to free the associated generic chips
and mappings.
[Bartosz: don't emit an error message on devres allocation failure]
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: net2280: Fix double free in probe error path
usb_initialize_gadget() installs gadget_release() as the release
callback for the embedded gadget device. The struct net2280 instance is
therefore released through gadget_release() when the gadget device's last
reference is dropped.
The probe error path calls net2280_remove(), which tears down the
partially initialized device and drops the gadget reference with
usb_put_gadget(). Calling kfree(dev) afterwards can free the same object
again.
Drop the explicit kfree() and let the gadget device release callback
handle the final free. This issue was found by a static analysis tool
I am developing.
In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Disable broadcast TLB flush when PCID is disabled
Booting with "nopcid" clears X86_FEATURE_PCID and keeps CR4.PCIDE from being
set to one. On AMD CPUs that support INVLPGB, broadcast TLB flushing remains
enabled.
There are two checks that decide whether the global ASID code runs,
mm_global_asid() and consider_global_asid(), that key off of the
X86_FEATURE_INVLPGB feature. Once an mm becomes active on more than three
CPUs, consider_global_asid() assigns it a global ASID, after which
flush_tlb_mm_range() takes the broadcast_tlb_flush() path using a non-zero
PCID. Issuing an INVLPGB with a non-zero PCID while CR4.PCIDE is not set
results in a #GP:
Oops: general protection fault, kernel NULL pointer dereference 0x1: 0000 [#1] SMP NOPTI
CPU: 158 UID: 0 PID: 3119 Comm: snap Not tainted 7.1.0-rc3 #1 PREEMPT(full)
Hardware name: ...
RIP: 0010:broadcast_tlb_flush
Code: ... 89 da 48 83 c8 07 <0f> 01 fe eb 08 cc cc cc ...
Call Trace:
<TASK>
flush_tlb_mm_range
ptep_clear_flush
wp_page_copy
? _raw_spin_unlock
__handle_mm_fault
handle_mm_fault
do_user_addr_fault
exc_page_fault
asm_exc_page_fault
All processors that support broadcast TLB invalidation also have PCID support,
so it is only the "nopcid" scenario that is of concern. In this situation just
disable the broadcast TLB support using the CPUID dependency support by making
X86_FEATURE_INVLPGB dependent on X86_FEATURE_PCID.
[ bp: Massage commit message. ]
In the Linux kernel, the following vulnerability has been resolved:
regulator: tps65219: fix irq_data.rdev not being assigned
Commit 64a6b577490c ("regulator: tps65219: Remove debugging helper
function") removed the tps65219_get_rdev_by_name() helper along with
the irq_data.rdev assignment that depended on it. This left
irq_data.rdev uninitialized for all IRQs, causing undefined behavior
when regulator_notifier_call_chain() is called from the IRQ handler:
Internal error: Oops: 0000000096000004
pc : regulator_notifier_call_chain
lr : tps65219_regulator_irq_handler
Call trace:
regulator_notifier_call_chain
tps65219_regulator_irq_handler
handle_nested_irq
regmap_irq_thread
irq_thread_fn
irq_thread
kthread
ret_from_fork
Instead of restoring a dedicated lookup array, restructure the probe
function to combine regulator registration with IRQ registration in
the same loop. This way the rdev returned by devm_regulator_register()
is naturally available for assigning to irq_data.rdev without any
auxiliary data structure.
Non-regulator IRQs (SENSOR, TIMEOUT) that don't correspond to any
registered regulator are registered with rdev=NULL, and the IRQ handler
is protected with a NULL check to avoid crashing.
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/dsi: don't dump registers past the mapped region
On DSI 6G platforms the IO address space is internally adjusted by
io_offset. Later this adjusted address might be used for memory dumping.
However the size that is used for memory dumping isn't adjusted to
account for the io_offset, leading to the potential access to the
unmapped region. Lower ctrl_size by the io_offset value to prevent
access past the mapped area.
msm_disp_snapshot_add_block+0x1d4/0x3c8 [msm] (P)
msm_dsi_host_snapshot+0x4c/0x78 [msm]
msm_dsi_snapshot+0x28/0x50 [msm]
msm_disp_snapshot_capture_state+0x74/0x140 [msm]
msm_disp_snapshot_state_sync+0x60/0x90 [msm]
_msm_disp_snapshot_work+0x30/0x90 [msm]
kthread_worker_fn+0xdc/0x460
kthread+0x120/0x140
Patchwork: https://patchwork.freedesktop.org/patch/721747/
In the Linux kernel, the following vulnerability has been resolved:
block: recompute nr_integrity_segments in blk_insert_cloned_request
blk_insert_cloned_request() already recomputes nr_phys_segments
against the bottom queue, because "the queue settings related to
segment counting may differ from the original queue." The exact same
reasoning applies to integrity segments: a stacked driver's underlying
queue can have tighter virt_boundary_mask, seg_boundary_mask, or
max_segment_size than the top queue, in which case
blk_rq_count_integrity_sg() against the bottom queue produces a
different count than the cached rq->nr_integrity_segments inherited
from the source request by blk_rq_prep_clone().
When the cached count is lower than the bottom queue's actual count,
blk_rq_map_integrity_sg() trips
BUG_ON(segments > rq->nr_integrity_segments);
on dispatch. The same families of stacked setups that motivated the
existing nr_phys_segments recompute -- dm-multipath fanning out to
nvme-rdma in particular -- can produce this.
Mirror the nr_phys_segments handling: when the request carries
integrity, recompute nr_integrity_segments against the bottom queue
and reject the request if it exceeds the bottom queue's
max_integrity_segments. blk_rq_count_integrity_sg() and
queue_max_integrity_segments() are both already available via
<linux/blk-integrity.h>, which blk-mq.c includes.
This closes a latent gap in the stacking contract and brings the
integrity-segment accounting in line with the existing
phys-segment accounting.
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind
uvc_function_bind() walks &opts->extension_units twice without holding
opts->lock:
- directly, for the iExtension string-descriptor fixup loop;
- indirectly, four times via uvc_copy_descriptors() (once per speed),
where the helper iterates uvc->desc.extension_units (which aliases
&opts->extension_units) to size and emit XU descriptors.
The configfs side (uvcg_extension_make / uvcg_extension_drop, in
drivers/usb/gadget/function/uvc_configfs.c) takes opts->lock around its
list_add_tail / list_del operations. A privileged userspace process
that holds the configfs subtree open and writes the gadget UDC name
to bind the function while concurrently rmdir()'ing an extensions
subdir can race uvcg_extension_drop() against the bind-time list walks
and dereference a freed struct uvcg_extension.
Hold opts->lock from the start of the XU string-descriptor fixup
through the last uvc_copy_descriptors() call, releasing on the
descriptor-error path via a new error_unlock label that drops the
lock before falling through to the existing error label. This
matches the locking discipline of the configfs callbacks and removes
the only remaining unsynchronised reader of the XU list during bind.
Reachability: only privileged processes that can mount configfs and
write to gadget UDC files can trigger the race, so this is a
correctness fix rather than a security boundary.