In the Linux kernel, the following vulnerability has been resolved:
crypto: jitterentropy - replace long-held spinlock with mutex
jent_kcapi_random() serializes the shared jitterentropy state, but it
currently holds a spinlock across the jent_read_entropy() call. That
path performs expensive jitter collection and SHA3 conditioning, so
parallel readers can trigger stalls as contending waiters spin for
the same lock.
To prevent non-preemptible lock hold, replace rng->jent_lock with a
mutex so contended readers sleep instead of spinning on a shared lock
held across expensive entropy generation.
In the Linux kernel, the following vulnerability has been resolved:
tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR
In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an
uninitialised on-stack struct sockaddr_storage to userspace via
ifr_hwaddr, but netif_get_mac_address() only writes sa_family and
dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised.
Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a
macvtap chardev returns kernel .text and direct-map pointers, defeating
KASLR.
Initialise ss at declaration.
In the Linux kernel, the following vulnerability has been resolved:
net/sched: fix pedit partial COW leading to page cache corruption
tcf_pedit_act() computes the COW range for skb_ensure_writable()
once before the key loop using tcfp_off_max_hint, but the hint does
not account for the runtime header offset added by typed keys. This
can leave part of the write region un-COW'd.
Fix by moving skb_ensure_writable() inside the per-key loop where
the actual write offset is known, and add overflow checking on the
offset arithmetic. For negative offsets (e.g. Ethernet header edits
at ingress), use skb_cow() to COW the headroom instead. Guard
offset_valid() against INT_MIN, where negation is undefined.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: use list_del_rcu for netlink hooks
nft_netdev_unregister_hooks and __nft_unregister_flowtable_net_hooks need
to use list_del_rcu(), this list can be walked by concurrent dumpers.
Add a new helper and use it consistently.
In the Linux kernel, the following vulnerability has been resolved:
selinux: allow multiple opens of /sys/fs/selinux/policy
Currently there can only be a single open of /sys/fs/selinux/policy at
any time. This allows any process to block any other process from
reading the kernel policy. The original motivation seems to have been
a mix of preventing an inconsistent view of the policy size and
preventing userspace from allocating kernel memory without bound, but
this is arguably equally bad. Eliminate the policy_opened flag and
shrink the critical section that the policy mutex is held. While we
are making changes here, drop a couple of extraneous BUG_ONs.
In the Linux kernel, the following vulnerability has been resolved:
lib: test_hmm: evict device pages on file close to avoid use-after-free
Patch series "Minor hmm_test fixes and cleanups".
Two bugfixes a cleanup for the HMM kernel selftests. These were mostly
reported by Zenghui Yu with special thanks to Lorenzo for analysing and
pointing out the problems.
This patch (of 3):
When dmirror_fops_release() is called it frees the dmirror struct but
doesn't migrate device private pages back to system memory first. This
leaves those pages with a dangling zone_device_data pointer to the freed
dmirror.
If a subsequent fault occurs on those pages (eg. during coredump) the
dmirror_devmem_fault() callback dereferences the stale pointer causing a
kernel panic. This was reported [1] when running mm/ksft_hmm.sh on arm64,
where a test failure triggered SIGABRT and the resulting coredump walked
the VMAs faulting in the stale device private pages.
Fix this by calling dmirror_device_evict_chunk() for each devmem chunk in
dmirror_fops_release() to migrate all device private pages back to system
memory before freeing the dmirror struct. The function is moved earlier
in the file to avoid a forward declaration.
In the Linux kernel, the following vulnerability has been resolved:
io-wq: check that the predecessor is hashed in io_wq_remove_pending()
io_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled
work was the tail of its hash bucket. When doing this, it checks whether
the preceding entry in acct->work_list has the same hash value, but
never checks that the predecessor is hashed at all. io_get_work_hash()
is simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash
bits are never set for non-hashed work, so it returns 0. Thus, when a
hashed bucket-0 work is cancelled while a non-hashed work is its list
predecessor, the check spuriously passes and a pointer to the non-hashed
io_kiocb is stored in wq->hash_tail[0].
Because non-hashed work is dequeued via the fast path in
io_get_next_work(), which never touches hash_tail[], the stale pointer
is never cleared. Therefore, after the non-hashed io_kiocb completes and
is freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The
io_wq is per-task (tctx->io_wq) and survives ring open/close, so the
dangling pointer persists for the lifetime of the task; the next hashed
bucket-0 enqueue dereferences it in io_wq_insert_work() and
wq_list_add_after() writes through freed memory.
Add the missing io_wq_is_hashed() check so a non-hashed predecessor
never inherits a hash_tail[] slot.
In the Linux kernel, the following vulnerability has been resolved:
drm/vkms: Convert to DRM's vblank timer
Replace vkms' vblank timer with the DRM implementation. The DRM
code is identical in concept, but differs in implementation.
Vblank timers are covered in vblank helpers and initializer macros,
so remove the corresponding hrtimer in struct vkms_output. The
vblank timer calls vkms' custom timeout code via handle_vblank_timeout
in struct drm_crtc_helper_funcs.
In the Linux kernel, the following vulnerability has been resolved:
RDMA/hns: Fix WQ_MEM_RECLAIM warning
When sunrpc is used, if a reset triggered, our wq may lead the
following trace:
workqueue: WQ_MEM_RECLAIM xprtiod:xprt_rdma_connect_worker [rpcrdma]
is flushing !WQ_MEM_RECLAIM hns_roce_irq_workq:flush_work_handle
[hns_roce_hw_v2]
WARNING: CPU: 0 PID: 8250 at kernel/workqueue.c:2644 check_flush_dependency+0xe0/0x144
Call trace:
check_flush_dependency+0xe0/0x144
start_flush_work.constprop.0+0x1d0/0x2f0
__flush_work.isra.0+0x40/0xb0
flush_work+0x14/0x30
hns_roce_v2_destroy_qp+0xac/0x1e0 [hns_roce_hw_v2]
ib_destroy_qp_user+0x9c/0x2b4
rdma_destroy_qp+0x34/0xb0
rpcrdma_ep_destroy+0x28/0xcc [rpcrdma]
rpcrdma_ep_put+0x74/0xb4 [rpcrdma]
rpcrdma_xprt_disconnect+0x1d8/0x260 [rpcrdma]
xprt_rdma_connect_worker+0xc0/0x120 [rpcrdma]
process_one_work+0x1cc/0x4d0
worker_thread+0x154/0x414
kthread+0x104/0x144
ret_from_fork+0x10/0x18
Since QP destruction frees memory, this wq should have the WQ_MEM_RECLAIM.