In the Linux kernel, the following vulnerability has been resolved:
iomap: avoid avoid truncating 64-bit offset to 32 bits
on 32-bit kernels, iomap_write_delalloc_scan() was inadvertently using a
32-bit position due to folio_next_index() returning an unsigned long.
This could lead to an infinite loop when writing to an xfs filesystem.
In the Linux kernel, the following vulnerability has been resolved:
dm thin: make get_first_thin use rcu-safe list first function
The documentation in rculist.h explains the absence of list_empty_rcu()
and cautions programmers against relying on a list_empty() ->
list_first() sequence in RCU safe code. This is because each of these
functions performs its own READ_ONCE() of the list head. This can lead
to a situation where the list_empty() sees a valid list entry, but the
subsequent list_first() sees a different view of list head state after a
modification.
In the case of dm-thin, this author had a production box crash from a GP
fault in the process_deferred_bios path. This function saw a valid list
head in get_first_thin() but when it subsequently dereferenced that and
turned it into a thin_c, it got the inside of the struct pool, since the
list was now empty and referring to itself. The kernel on which this
occurred printed both a warning about a refcount_t being saturated, and
a UBSAN error for an out-of-bounds cpuid access in the queued spinlock,
prior to the fault itself. When the resulting kdump was examined, it
was possible to see another thread patiently waiting in thin_dtr's
synchronize_rcu.
The thin_dtr call managed to pull the thin_c out of the active thins
list (and have it be the last entry in the active_thins list) at just
the wrong moment which lead to this crash.
Fortunately, the fix here is straight forward. Switch get_first_thin()
function to use list_first_or_null_rcu() which performs just a single
READ_ONCE() and returns NULL if the list is already empty.
This was run against the devicemapper test suite's thin-provisioning
suites for delete and suspend and no regressions were observed.
In the Linux kernel, the following vulnerability has been resolved:
virtio-blk: don't keep queue frozen during system suspend
Commit 4ce6e2db00de ("virtio-blk: Ensure no requests in virtqueues before
deleting vqs.") replaces queue quiesce with queue freeze in virtio-blk's
PM callbacks. And the motivation is to drain inflight IOs before suspending.
block layer's queue freeze looks very handy, but it is also easy to cause
deadlock, such as, any attempt to call into bio_queue_enter() may run into
deadlock if the queue is frozen in current context. There are all kinds
of ->suspend() called in suspend context, so keeping queue frozen in the
whole suspend context isn't one good idea. And Marek reported lockdep
warning[1] caused by virtio-blk's freeze queue in virtblk_freeze().
[1] https://lore.kernel.org/linux-block/ca16370e-d646-4eee-b9cc-87277c89c43c@samsung.com/
Given the motivation is to drain in-flight IOs, it can be done by calling
freeze & unfreeze, meantime restore to previous behavior by keeping queue
quiesced during suspend.
In the Linux kernel, the following vulnerability has been resolved:
net/sctp: Prevent autoclose integer overflow in sctp_association_init()
While by default max_autoclose equals to INT_MAX / HZ, one may set
net.sctp.max_autoclose to UINT_MAX. There is code in
sctp_association_init() that can consequently trigger overflow.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Add check for granularity in dml ceil/floor helpers
[Why]
Wrapper functions for dcn_bw_ceil2() and dcn_bw_floor2()
should check for granularity is non zero to avoid assert and
divide-by-zero error in dcn_bw_ functions.
[How]
Add check for granularity 0.
(cherry picked from commit f6e09701c3eb2ccb8cb0518e0b67f1c69742a4ec)
In the Linux kernel, the following vulnerability has been resolved:
fs: relax assertions on failure to encode file handles
Encoding file handles is usually performed by a filesystem >encode_fh()
method that may fail for various reasons.
The legacy users of exportfs_encode_fh(), namely, nfsd and
name_to_handle_at(2) syscall are ready to cope with the possibility
of failure to encode a file handle.
There are a few other users of exportfs_encode_{fh,fid}() that
currently have a WARN_ON() assertion when ->encode_fh() fails.
Relax those assertions because they are wrong.
The second linked bug report states commit 16aac5ad1fa9 ("ovl: support
encoding non-decodable file handles") in v6.6 as the regressing commit,
but this is not accurate.
The aforementioned commit only increases the chances of the assertion
and allows triggering the assertion with the reproducer using overlayfs,
inotify and drop_caches.
Triggering this assertion was always possible with other filesystems and
other reasons of ->encode_fh() failures and more particularly, it was
also possible with the exact same reproducer using overlayfs that is
mounted with options index=on,nfs_export=on also on kernels < v6.6.
Therefore, I am not listing the aforementioned commit as a Fixes commit.
Backport hint: this patch will have a trivial conflict applying to
v6.6.y, and other trivial conflicts applying to stable kernels < v6.6.
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_fs: Remove WARN_ON in functionfs_bind
This commit addresses an issue related to below kernel panic where
panic_on_warn is enabled. It is caused by the unnecessary use of WARN_ON
in functionsfs_bind, which easily leads to the following scenarios.
1.adb_write in adbd 2. UDC write via configfs
================= =====================
->usb_ffs_open_thread() ->UDC write
->open_functionfs() ->configfs_write_iter()
->adb_open() ->gadget_dev_desc_UDC_store()
->adb_write() ->usb_gadget_register_driver_owner
->driver_register()
->StartMonitor() ->bus_add_driver()
->adb_read() ->gadget_bind_driver()
<times-out without BIND event> ->configfs_composite_bind()
->usb_add_function()
->open_functionfs() ->ffs_func_bind()
->adb_open() ->functionfs_bind()
<ffs->state !=FFS_ACTIVE>
The adb_open, adb_read, and adb_write operations are invoked from the
daemon, but trying to bind the function is a process that is invoked by
UDC write through configfs, which opens up the possibility of a race
condition between the two paths. In this race scenario, the kernel panic
occurs due to the WARN_ON from functionfs_bind when panic_on_warn is
enabled. This commit fixes the kernel panic by removing the unnecessary
WARN_ON.
Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 14.542395] Call trace:
[ 14.542464] ffs_func_bind+0x1c8/0x14a8
[ 14.542468] usb_add_function+0xcc/0x1f0
[ 14.542473] configfs_composite_bind+0x468/0x588
[ 14.542478] gadget_bind_driver+0x108/0x27c
[ 14.542483] really_probe+0x190/0x374
[ 14.542488] __driver_probe_device+0xa0/0x12c
[ 14.542492] driver_probe_device+0x3c/0x220
[ 14.542498] __driver_attach+0x11c/0x1fc
[ 14.542502] bus_for_each_dev+0x104/0x160
[ 14.542506] driver_attach+0x24/0x34
[ 14.542510] bus_add_driver+0x154/0x270
[ 14.542514] driver_register+0x68/0x104
[ 14.542518] usb_gadget_register_driver_owner+0x48/0xf4
[ 14.542523] gadget_dev_desc_UDC_store+0xf8/0x144
[ 14.542526] configfs_write_iter+0xf0/0x138
In the Linux kernel, the following vulnerability has been resolved:
iio: adc: at91: call input_free_device() on allocated iio_dev
Current implementation of at91_ts_register() calls input_free_deivce()
on st->ts_input, however, the err label can be reached before the
allocated iio_dev is stored to st->ts_input. Thus call
input_free_device() on input instead of st->ts_input.