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:
af_unix: Reject SIOCATMARK on non-stream sockets
SIOCATMARK reports whether the receive queue is at the urgent mark for
MSG_OOB.
In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets.
SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(),
so they should not support SIOCATMARK either.
Return -EOPNOTSUPP for non-stream sockets before checking the receive
queue.
In the Linux kernel, the following vulnerability has been resolved:
ip6_vti: set netns_immutable on the fallback device.
john1988 and Noam Rathaus reported that vti6_init_net() does not set the
netns_immutable flag on the per-netns fallback tunnel device (ip6_vti0).
Other similar tunnel drivers (like ip6_tunnel, sit, ip6_gre, and ip_tunnel)
correctly set this flag during their fallback device initialization to
prevent them from being moved to another network namespace.
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/mlx4: Fix mis-use of RCU in mlx4_srq_event()
Sashiko points out the radix_tree itself is RCU safe, but nothing ever
frees the mlx4_srq struct with RCU, and it isn't even accessed within the
RCU critical section. It also will crash if an event is delivered before
the srq object is finished initializing.
Use the spinlock since it isn't easy to make RCU work, use
refcount_inc_not_zero() to protect against partially initialized objects,
and order the refcount_set() to be after the srq is fully initialized.