In the Linux kernel, the following vulnerability has been resolved:
net: team: free skb when broadcast has no txable port
bc_transmit() sends the original skb through the last txable port.
When no port is txable, it returns false without consuming the skb, but
team_xmit() still returns NETDEV_TX_OK. AF_PACKET sends then retain the
skb and its socket write-memory charge.
A TX-enabled, link-down port keeps the broadcast transmit op installed.
Carrier can stay up through a second link-up, TX-disabled port or be
forced on by userspace. Free the original skb on the no-port path while
leaving the existing drop accounting intact.
Discovered by Sashiko during review of previous commit.
In the Linux kernel, the following vulnerability has been resolved:
net: bridge: avoid recursive multicast port cleanup
br_multicast_sg_del_exclude_ports() removes automatically added STAR_EXCL
port groups by calling br_multicast_del_pg(). For S,G entries, that
deletion calls back into br_multicast_sg_del_exclude_ports(), so a large
number of STAR_EXCL ports consumes one kernel stack frame per port and can
hit the stack guard page.
Keep the complete port-group deletion path for cleanup, but suppress the
S,G exclude-port cleanup while that helper is already walking the same
entry. Normal deletion callers retain the existing behavior.
In the Linux kernel, the following vulnerability has been resolved:
mmc: sdhci-sprd: disable runtime PM on remove
sdhci_sprd_probe() enables runtime PM, while sdhci_sprd_remove() does
not perform the corresponding runtime PM cleanup.
The probe failure path disables runtime PM before disabling the clocks,
but the normal remove path directly disables clocks that are also
managed by the runtime PM callbacks. If the device is runtime
suspended, those clocks may already be disabled.
Resume the device before removal, disable runtime PM and drop the
temporary runtime PM reference before disabling the clocks.
This issue was found by manual code inspection.
In the Linux kernel, the following vulnerability has been resolved:
net: team: stop reusing skb after queue override
A nonzero dev_queue_xmit() result does not return ownership of the skb.
When an override port's qdisc drops it, the queue override helper used to
try another port or the mode transmit op with the freed skb.
Return the handoff decision separately from transmit success. Select only
the first override port under RCU and stop after handing it the skb,
regardless of the lower transmit result. Keep the existing success and
drop accounting.
BUG: KASAN: slab-use-after-free in sk_skb_reason_drop
Write of size 4 by task poc/5040
sk_skb_reason_drop (net/core/skbuff.c:1240)
dev_kfree_skb_any_reason (net/core/dev.c:3470)
ab_transmit (drivers/net/team/team_mode_activebackup.c:49)
team_xmit (drivers/net/team/team_core.c:1849)
__dev_direct_xmit (net/core/dev.c:4934)
Freed by task 5040:
__tcf_kfree_skb_list (net/sched/sch_generic.c:43)
__dev_queue_xmit (net/core/dev.c:4831)
team_xmit (drivers/net/team/team_core.c:1846)
Kernel panic - not syncing: KASAN: panic_on_warn set ...
In the Linux kernel, the following vulnerability has been resolved:
regulator: of: fill in supply names in of_regulator_bulk_get_all()
of_regulator_bulk_get_all() returns an array it allocated itself, and
fills in only the consumer of each entry. Every other way of getting a
bulk array has the supply name set, because the caller provides it, and
the core expects it to be there: regulator_bulk_enable() prints it when
a supply fails to enable, so a caller that hands such an array to it
dereferences uninitialised memory on that path.
Copy each name into the array's own allocation, right behind the
entries, so that it shares the array's lifetime and callers still have
nothing extra to free. That also retires the fixed 64 byte stack buffer
the names were assembled in, which is_supply_name() never bounded the
copy against.
In the Linux kernel, the following vulnerability has been resolved:
optee: register TEE devices only once fully initialized
optee_probe() called tee_device_register() on both the client and the
supplicant device before the rest of struct optee had been initialized.
tee_device_register() calls cdev_device_add(), which does two things at
once: it creates /dev/tee0 and /dev/teepriv0, and it links the device
into the tee class so that class_find_device() can find it. From that
moment on the device is reachable both from user space via tee_open()
and from kernel space via tee_client_open_context(). The only gate in
teedev_open() is tee_device_get(), which merely checks that
teedev->desc is non-NULL, which was already set by tee_device_alloc().
Therefore, there is effectively no gate at all.
A context opened in that window can run against a struct optee where
- optee->call_queue.mutex is not initialized by optee_cq_init()
- optee->supp mutex and completions is not initialized by
optee_supp_init()
- optee->rpmb_dev_mutex is not initialized yet,
- the message argument cache is not initialized by
optee_shm_arg_cache_init()
- optee->ctx is still NULL
Any open session or invoke during this window takes uninitialized
mutexes and dereferences a NULL pointer.
Fix it by moving both tee_device_register() calls down to the point
where all of struct optee is set up.
[JW: adding fixes and cc]
In the Linux kernel, the following vulnerability has been resolved:
net: sparx5: free the matchall entry on destroy
sparx5_tc_matchall_replace() allocates a struct sparx5_mall_entry for
every offloaded matchall filter and adds it to sparx5->mall_entries.
sparx5_tc_matchall_destroy() removes the entry from the list, but never
frees it, so the entry of every deleted mirror and goto matchall filter
is leaked.
Free the entry after unlinking it.
The leak was discovered by an AI code review agent, and reproduced with
kmemleak on a lan969x EV board (EV23X71A) by repeatedly adding and
deleting matchall mirror and goto filters. With the fix, kmemleak no
longer reports the leak.
A memory leak vulnerability in the Linux kernel's power sequencing component for pcie-m2 was fixed. The function of_regulator_bulk_get_all() allocates an array that the caller must free, but pwrseq-pcie-m2.c did not free this array, causing a memory leak. The fix adds an explicit kfree() call to release the allocated memory.
In the Linux kernel, the following vulnerability has been resolved:
dm: fix reading free memory in do_resume
When do_resume calls dm_table_get_mode(new_map), the call is done without
holding any locks (it only holds a reference to the md). It may be
possible that another concurrent ioctl on the same device will swap table
after dm_swap_table and before dm_table_get_mode. In this case,
dm_table_get_mode(new_map) reads freed memory.
This race condition was triggered by syzbot.
This commit fixes the race by reading mode of the new table before
dm_swap_table. Note that new_map is also passed to dm_ima_need_measure,
but this function doesn't attempt to dereference it, so this call should
be safe.
Note that this is not a security bug because only root can trigger it and
the commonly used tools such as lvm or cryptsetup do not call the ioctls
concurrently, so that they can't trigger it acceidentally.
In the Linux kernel, the following vulnerability has been resolved:
memstick: rtsx_usb_ms: complete requests after eject instead of dropping them
memstick_check() can pass its host->removing check just before
rtsx_usb_ms_drv_remove() sets eject/removing. Its next request is then
silently dropped: rtsx_usb_ms_request() skips schedule_work() once eject
is set, and drv_remove's cancel_work_sync() can also cancel a queued
handle_req before it picks the request up. Nobody completes
card->mrq_complete.
Once memstick core waits for requests without a timeout ("memstick: core:
wait for request completion before freeing card"), this hangs removal:
memstick_check() never returns and memstick_remove_host() blocks in
flush_workqueue():
INFO: task kworker/u10:3:65 blocked for more than 20 seconds.
Workqueue: kmemstick memstick_check
__wait_for_common
memstick_check
INFO: task kworker/1:1:33 blocked for more than 20 seconds.
Workqueue: usb_hub_wq hub_event
__flush_workqueue
memstick_remove_host
rtsx_usb_ms_drv_remove
Never drop a request. rtsx_usb_ms_request() always schedules handle_req,
and handle_req fails requests with -ENOMEDIUM once eject is set, without
touching the device. drv_remove flushes handle_req instead of cancelling
it, and cancels it only after memstick_remove_host(), when no new
request can arrive, so it cannot run on a freed host.
The host_mutex drain in drv_remove is removed: handle_req always leaves
host->req NULL when it finishes, so the drain never had anything to do,
and it would now race with handle_req.
In the Linux kernel, the following vulnerability has been resolved:
dm-crypt: reject the lmk IV mode with AEAD ciphers
A "capi:" table line that pairs an AEAD cipher with the lmk IV mode,
for example "capi:gcm(aes)-lmk" with the integrity:28:aead option,
causes an oops when it is loaded. lmk sets tfms_count to 64, but
crypt_alloc_tfms_aead only allocates one transform, so crypt_setkey
reads past the end of the tfms_aead array and calls crypto_aead_setkey
on the values it finds there.
lmk exists for compatibility with Loop-AES, which uses CBC, so refuse
it with an AEAD cipher rather than allocate 64 AEAD transforms. The
check cannot go in crypt_iv_lmk_ctr with the other lmk checks, because
the IV constructor runs after crypt_set_key.
Note that this is not a security bug because the memory corruption can
only be triggered by root.
A vulnerability in the Linux kernel's io_uring/net subsystem was resolved that involved incorrect handling of IPv6 sockaddr length in connection filtering. The issue caused connect filters to see zeroed port and address fields when the sockaddr_in6 length was 24 bytes (SIN6_LEN_RFC2133), allowing filters that deny connections based on port or address to be bypassed. The fix aligns the length threshold to SIN6_LEN_RFC2133, ensuring filters correctly see the real destination address and port.
In the Linux kernel, the following vulnerability has been resolved:
mmc: mtk-sd: Cancel request timeout work on remove
The driver queues req_timeout while a request is active.
msdc_request_done() uses cancel_delayed_work(), which does not wait for
a timeout callback that has already started.
The timeout callback calls mmc_request_done(), which wakes the request
waiter, and then continues to use host->dev_comp and check the SDIO IRQ.
During unbind, msdc_drv_remove() can return and the managed mmc_host can
be freed before the callback finishes.
KASAN reported use-after-free accesses in msdc_request_done() and
msdc_recheck_sdio_irq() in each of three unbind tests. The same tests
completed without a kernel diagnostic after this change.
Call cancel_delayed_work_sync() after mmc_remove_host() has stopped new
requests and before the driver releases the host resources.
In the Linux kernel, the following vulnerability has been resolved:
KEYS: Fix add_key() race with keyring restriction
__key_create_or_update() snapshots keyring->restrict_link before taking
the destination keyring's semaphore. keyring_restrict() installs a
restriction while holding that semaphore.
This allows a writer to observe no restriction, wait for the keyring
owner to install a reject-all restriction and return successfully, and
then link a key using the stale NULL snapshot. The writer only needs
write permission on the destination keyring.
Move the restrict_link read after __key_link_lock() and
__key_link_begin(). The read and the subsequent restriction check are
then serialized with restriction installation by keyring->sem.
The race was reproduced on v7.2.8 in 19 executions where restriction
installation returned before the link completed. All 19 linked the key
despite the reject-all restriction. With this change, 312 executions
reached the same ordering and every add_key() call failed with -EPERM.
The issue was found by manual concurrency analysis assisted by AI-based
analysis and independently verified with a QEMU reproducer and kernel
instrumentation.
A vulnerability in the Linux kernel's statmount functionality allowed reading the parent of an unmounted mount under mount_lock, potentially leading to dereferencing a mount that has already been freed. This issue arises because statmount_mnt_basic() reads the parent mount's IDs without proper synchronization when the mount has been unmounted but kept alive by a file descriptor. The flaw has been resolved in the Linux kernel.
A vulnerability in the Linux kernel's mount notification system allows a mount to be queued multiple times for notifications, leading to use-after-free memory access. This occurs because mnt_notify_add() does not check if a mount is already on the notification list, causing corrupted list state and potential kernel memory errors. The issue affects mounts with the MNT_SHRINKABLE flag, such as submounts of NFS, AFS, CIFS, and tracefs. The flaw has been resolved by initializing the notification list properly and preventing duplicate queueing of mounts.
In the Linux kernel, the following vulnerability has been resolved:
namespace: don't inherit MNT_UMOUNT in clone_mnt()
MNT_UMOUNT gets raised on a mount that umount_tree() or umount_one() has
taken out of its namespace. It's never cleared. __detach_mounts()
unhooks a mount that carries it instead of unmounting it.
disconnect_mount() lets an unmounted child stay attached only if its
parent carries it. propagate_umount() takes it as the sign that a mount
is going to be unmounted when it decides what else can be unmounted,
where a chain of locked mounts ends and where a for reparenting an
overmount.
clone_mnt() copies the flags of the source and only masks
MNT_INTERNAL_FLAGS which doesn't include MNT_UMOUNT. A mount that was
lazily unmounted but is kept alive by a file descriptor can still be
copied when its root is an nsfs or pidfs file because may_copy_tree()
accepts those before checking whether the source is mounted at all:
mount --bind /proc/self/ns/net /tmp/x
exec 3< /tmp/x
umount -l /tmp/x
mount --bind /proc/self/fd/3 /tmp/y
The mount on /tmp/y is attached to the caller's namespace with
MNT_UMOUNT already set and every copy of it inherits the flag again.
That causes a number of bugs:
- Unlink its mountpoint from a mount namespace where it isn't one.
__detach_mounts() takes it for a mount that was unmounted earlier,
unhooks it from its parent and drops the reference the namespace
holds on it. It stays in the namespace with one reference too few
and as its own parent, so it can't be unmounted through the file
descriptor anymore and the namespace never finds it again. When the
namespace goes away it's leaked and points to a freed struct
mnt_namespace that may_change_propagation() and anon_ns_root() read
on the next propagation change or mount_setattr() through the file
descriptor.
- Make it shared and unmount a peer. trace_transfers() follows the
flag from the peer into it and strips it from its peer group.
- Let a propagated umount reach it. gather_candidates() marks it with
T_UMOUNT_CANDIDATE but never puts it on the candidate list, so the
mark is never cleared and every later propagated umount skips it. If
it's the parent of a locked mount handle_locked() takes it as the
cutoff and commits the locked child that should have stayed and
disconnect_mount() leaves that child attached to it, unmounted under
a mounted parent, which is what disconnect_mount() exists to
prevent. When the namespace goes away umount_tree() visits the child
a second time. And once __detach_mounts() has made it its own parent
reparent() never finds the end of the chain of unmounted parents.
A clone is a new mount that has never been unmounted. Add MNT_UMOUNT
to MNT_INTERNAL_FLAGS so clone_mnt() never copies it. And warn when
umount_tree() reaches a mount that already has it set.
In the Linux kernel, the following vulnerability has been resolved:
fs: don't silently unmount busy mounts
The propagate_mount_busy() helper exists to decide whether a synchronous
can suceed. It does that by looking at the copies of the victims in the
mounts its parent propagates to. One of those functions from propagation
hell.
It skips a copy that has child mounts except for the case of a single
child mount covering the copy's root. That algorithm used to be exact.
It isn't anymore.
Originally only childless copies were unmounted during propagation.
And 1064f874abc0 ("mnt: Tuck mounts under others instead of creating
shadow/side mounts.") ended up adding covered mounts to both sides in
one go.
Along came 99b19d16471e ("mnt: In propgate_umount handle visiting mounts
in any order") and that started to unmount more than before:
[1]: A copy of a mount is unmounted when each of its children is either
its overmount or a copy of the victim itself. In the former case
the overmount gets reparented. In the latter case the copy of the
victim will end up being unmounted.
So propagate_umount() ended up being rewritten without adjusting
propagate_mount_busy(). And currently propagate_mount_busy() doesn't
look at copies of the victim that have two or more children nor a single
child that is not the overmount.
So any such copy in [1] is not checked for
references. The result is that a synchronous unmount succeeds, pulling
out a mount that is still in use.
A container can run into this with its own mounts. The host shares a
tree with the container and the host has a mount in that tree:
mount -t tmpfs none /mnt
mount --make-shared /mnt
mount -t tmpfs none /mnt/a
The container's /mnt is a slave copy of the host mount. The container
now takes a detached copy of the tree and mounts that copy beneath its
propagated copy of /mnt/a and keeps the file descriptor to the tree
open:
unshare -m --propagation unchanged
mount --make-rslave /
fd = open_tree(AT_FDCWD, "/mnt", OPEN_TREE_CLONE | AT_RECURSIVE)
move_mount(fd, "", AT_FDCWD, "/mnt/a", MOVE_MOUNT_BENEATH)
grep /mnt /proc/self/mountinfo
775 355 ... /mnt ... master:646
777 775 ... /mnt/a ... master:646
776 777 ... /mnt/a ... master:647
778 777 ... /mnt/a/a ... master:647
The now attached tree (777) is now mounted beneath the container's copy
of /mnt/a. That's also where the host mount sits (as seen from the host
mount namespace). So the propagated copy (776) of the host's mount is on
top of its root and the copy of that (778) is inside it. Now the host
runs:
umount /mnt/a
and it succeeds. The moved tree tree and the copy inside of it are gone
from the container. Now only the propagated copy is left and it got
reparented to where it was before:
grep /mnt /proc/self/mountinfo
775 355 ... /mnt ... master:646
776 775 ... /mnt/a ...
But the file descriptor still refers to the moved tree. So a synchronous
umount detached a mount that is still in use.
Teach propagate_mount_busy() the same checks that propagate_umount()
does. It now checks for a single victim mount without children
for which it can assume that MNT_LOCKED is cleared on every copy like
propagate_umount() does. The copies form chains. IOW, when a copy itself
receives propagation from the victim's parent then the mount at the same
mountpoint inside that copy is a copy as well. Whether a mount receives
propagation from the victim's can simply be checked by walking its
masters. Walk each chain once from its top so we are sure that nested
copies stay linear. Check every reference once of every copy that gets
unmounted.
In the Linux kernel, the following vulnerability has been resolved:
riscv: futex: untag the user pointer before the atomic access
access_ok() checks untagged_addr(uaddr), but arch_futex_atomic_op_inuser()
and futex_atomic_cmpxchg_inatomic() hand the raw uaddr to the inline asm
amoswap/amoadd/.../lr.w+sc.w through the "+m" (*uaddr) operand. When the
tagged address ABI is enabled (CONFIG_RISCV_ISA_SUPM, prctl
PR_SET_TAGGED_ADDR_CTRL with PMLEN != 0), those two addresses differ: a
user pointer whose top PMLEN bits hold a tag passes access_ok() after
untagging, but the atomic is then performed on the still-tagged raw
address.
Supervisor-mode data accesses are not subject to the U-mode pointer
masking (that is governed by menvcfg.PMM, which the kernel does not set),
so hardware does not strip the tag for the kernel's own access. With
Sv57 and PMLEN=16 the tag bits overlap the canonical-address bits, so a
tagged pointer can name a canonical kernel virtual address (e.g. in the
linear map) whose untagged form is a valid user address. An unprivileged
process can thus make FUTEX_WAKE_OP perform an atomic read-modify-write on
an arbitrary kernel address, with the matching FUTEX_OP_CMP_* result
serving as a read oracle.
get_user()/put_user()/raw_copy_{to,from}_user() already untag the pointer
after the access_ok() check; do the same in the futex helpers so the
atomic operates on the address that was actually validated.
In the Linux kernel, the following vulnerability has been resolved:
namespace: check a submount for references right before unmounting it
shrink_submounts() and mark_mounts_for_expiry() first collect all the
mounts they are allowed to unmount and then unmount them.
Whether a mount is busy is decided by propagate_mount_busy() on the
tree. But unmounting the first mount changes the tree that the second
one propagates into. propagate_umount()
moves a surviving overmount off a copy it unmounts and mounts it where
the copy was mounted. If that's where the propagated copy of the second
victim is looked up the overmount becomes a candidate of the second
umount_tree(). It's childless and so trim_one() commits it without
looking at its reference count.
So a synchronous umount pulls out a busy mount that is in use somewhere
else and marks it MNT_SYNC_UMOUNT while it has users:
umount2(/tmp/plshrink/p1, 0) = 0 errno 0
cwd is (unreachable)
The same two umounts requested one after the other fail with EBUSY.
This needs a mount with MNT_SHRINKABLE, i.e., automounted submounts of
NFS, AFS and CIFS or the tracefs mount below debugfs. Bind mounts
inherit the flag.
Check each mount right before it is unmounted under the same hold of
namespace_sem and mount_lock as the umount itself. Make sure that the
algorithm stays linear.