In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: nv: Fix handling of XN[0] when !FEAT_XNX
XN has already been extracted from its bitfield position so using
FIELD_PREP() on the mask that clears XN[0] is completely broken, having
the effect of unconditionally granting execute permissions...
Fix the obvious mistake by manipulating the right bit.
In the Linux kernel, the following vulnerability has been resolved:
Revert "drm/xe: Skip exec queue schedule toggle if queue is idle during suspend"
This reverts commit 8533051ce92015e9cc6f75e0d52119b9d91610b6.
The idle-skip optimization bypasses GuC suspend, so the GPU may not
perform the context switch that flushes TLB entries for invalidated
userptr VMAs. In LR/preempt-fence VM mode, this can lead to missed TLB
invalidation and page faults during userptr invalidation tests.
Restore unconditional schedule toggling on suspend so the context-switch
TLB flush is always performed.
This optimization will be reintroduced with a fix that does not skip
suspend in LR/preempt-fence VM mode.
(cherry picked from commit 6a1e7934d9a6cf46aecae00a99c2603d1295e170)
In the Linux kernel, the following vulnerability has been resolved:
RDMA/srp: bound SRP_RSP sense copy by the received length
srp_process_rsp() copies sense data from rsp->data + resp_data_len,
where resp_data_len is the full 32-bit value supplied by the SRP target
and is never checked against the number of bytes actually received
(wc->byte_len). The copy length is bounded to SCSI_SENSE_BUFFERSIZE, so
at most 96 bytes are copied, but the source offset is not bounded.
A malicious or compromised SRP target on the InfiniBand/RoCE fabric that
the initiator has logged into can return an SRP_RSP with
SRP_RSP_FLAG_SNSVALID set and a large resp_data_len. The receive buffer
is allocated at the target-chosen max_ti_iu_len, so the source of the
sense copy lands past the bytes actually received; with resp_data_len
near 0xFFFFFFFF it is gigabytes past the buffer and the read faults.
Copy the sense data only if it has not been truncated, that is, only if
the response header, the response data, and the sense region fit within
the bytes actually received; otherwise drop the sense and log. The
in-tree iSER and NVMe-RDMA receive paths already bound their parse by
wc->byte_len; this brings ib_srp into line with them.
In the Linux kernel, the following vulnerability has been resolved:
RDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc
The cpu_id attribute supplied by user space through
UVERBS_ATTR_ALLOC_DMAH_CPU_ID is passed directly to cpumask_test_cpu()
without first verifying that the value is within the valid CPU range.
Passing such untrusted data to cpumask_test_cpu() may lead to an
out-of-bounds read of the underlying cpumask bitmap: the helper expands
to a test_bit() that indexes the bitmap by cpu_id / BITS_PER_LONG with
no bound check.
In addition, on kernels built with CONFIG_DEBUG_PER_CPU_MAPS it trips
the WARN_ON_ONCE() in cpumask_check(); combined with panic_on_warn this
turns a bad user input into a machine reboot.
Reject any cpu_id that is not smaller than nr_cpu_ids with -EINVAL
before it is used.
Reported by Smatch.
In the Linux kernel, the following vulnerability has been resolved:
RDMA/core: Validate the passed in fops for ib_get_ucaps()
Sashiko pointed out it is not safe to rely only on the devt because
char/block alias so if the user finds a block device with the same dev_t
it can masquerade as a ucap cdev fd.
Test the f_ops to only accept authentic cdevs.
In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: update file PMD counter before folio_put()
__split_huge_pmd_locked() updates the file/shmem RSS counter after
dropping the PMD mapping's folio reference. If folio_put() drops the last
reference, mm_counter_file() can later read freed folio state via
folio_test_swapbacked().
Move the counter update before folio_put().
In the Linux kernel, the following vulnerability has been resolved:
drm/virtio: fix dma_fence refcount leak on error in virtio_gpu_dma_fence_wait()
dma_fence_unwrap_for_each() internally calls dma_fence_unwrap_first()
which does cursor->chain = dma_fence_get(head), taking an extra
reference. On normal loop completion, dma_fence_unwrap_next()
releases this via dma_fence_chain_walk() -> dma_fence_put().
When virtio_gpu_do_fence_wait() fails and the function returns early
from inside the loop, the cursor->chain reference is never released.
This is the only caller in the entire kernel that does an early return
inside dma_fence_unwrap_for_each.
Add dma_fence_put(itr.chain) before the early return.
In the Linux kernel, the following vulnerability has been resolved:
io_uring/net: inherit IORING_CQE_F_BUF_MORE across bundle recv retries
When a bundle recv retries inside io_recv_finish(), the merge logic OR
the saved cflags from the previous iteration with the cflags returned by
the new iteration:
cflags = req->cqe.flags | (cflags & CQE_F_MASK);
Bits listed in CQE_F_MASK are inherited from the new iteration, and all
other bits (notably IORING_CQE_F_BUFFER and the buffer ID) come from the
saved cflags. Before this change CQE_F_MASK covered only
IORING_CQE_F_SOCK_NONEMPTY and IORING_CQE_F_MORE.
When using provided buffer rings (IOU_PBUF_RING_INC) with incremental
mode, and bundle recv, io_kbuf_inc_commit() can leave the head ring
entry partially consumed, __io_put_kbufs() then sets
IORING_CQE_F_BUF_MORE on the returned cflags so userspace knows the
buffer ID will be reused for subsequent completions.
Because IORING_CQE_F_BUF_MORE was not in CQE_F_MASK, the merge above
silently dropped it whenever the final retry iteration partially
consumed the buffer, and the subsequent req->cqe.flags = cflags &
~CQE_F_MASK save would have left a stale IORING_CQE_F_BUF_MORE in the
carried-over cflags had one been present. Userspace would then
wrongfully advance it ring head past an entry the kernel still uses.
Add IORING_CQE_F_BUF_MORE to CQE_F_MASK so it is both inherited from the
new iteration into the user-visible CQE and stripped from the saved
cflags between iterations.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Fix UAF at snd_timer_user_params()
At releasing a timer object, e.g. when a userspace timer
(CONFIG_SND_UTIMER) gets closed and snd_timer_free() is called, it
tries to detach the timer instances and release the resources.
However, it's still possible that other in-flight tasks are holding
the timer instance where the to-be-deleted timer object is associated,
and this may lead to racy accesses.
Fortunately, most of ioctls dealing with the timer instance list
already have the protection with register_mutex, and this also avoids
such races. But, SNDRV_TIMER_IOCTL_PARAMS isn't protected, hence the
concurrent ioctl may lead to use-after-free.
This patch just adds the guard with register_mutex to protect
snd_timer_user_params() for covering the code path as a quick
workaround. It's no hot-path but rather a rarely issued ioctl, so the
performance penalty doesn't matter.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Forcibly close timer instances at closing
When snd_timer object is freed via snd_timer_free() and still pending
snd_timer_instance objects are assigned to the timer object, it tries
to unlink all instances and just set NULL to each ti->timer, then
releases the resources immediately. The problem is, however, when
there are slave timer instances that are associated with a master
instance linked to this timer: namely, those slave instances still
point to the freed timer object although the master instance is
unlinked, which may lead to user-after-free. The bug can be easily
triggered particularly when a new userspace-driven timers
(CONFIG_SND_UTIMER) is involved, since it can create and delete the
timer object via a simple file open/close, while the other
applications may keep accessing to that timer.
This patch is an attempt to paper over the problem above: now instead
of just unlinking, call snd_timer_close[_locked]() forcibly for each
pending timer instance, so that all assigned slave timer instances are
properly detached, too. Since snd_timer_close() might be called later
by the driver that created that instance, the check of
SNDRV_TIMER_IFLG_DEAD is added at the beginning, too.