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.
In the Linux kernel, the following vulnerability has been resolved:
USB: serial: kl5kusb105: fix bulk-out buffer overflow
klsi_105_prepare_write_buffer() is called by the generic write path
with the bulk-out buffer and its size (bulk_out_size, 64 bytes). It
stores a two-byte length header at the start of the buffer and copies
the payload from the write fifo starting at buf + KLSI_HDR_LEN, but
passes the full buffer size as the number of bytes to copy:
count = kfifo_out_locked(&port->write_fifo, buf + KLSI_HDR_LEN,
size, &port->lock);
When the fifo holds at least size bytes, size bytes are copied starting
two bytes into the size-byte buffer, writing KLSI_HDR_LEN bytes past its
end. Copy at most size - KLSI_HDR_LEN bytes instead, leaving room for
the header as safe_serial already does.
Writing bulk_out_size or more bytes to the tty triggers a slab
out-of-bounds write, observed with KASAN by emulating the device with
dummy_hcd and raw-gadget:
BUG: KASAN: slab-out-of-bounds in kfifo_copy_out+0x83/0xc0
Write of size 64 at addr ffff888112c62202 by task python3
kfifo_copy_out
klsi_105_prepare_write_buffer [kl5kusb105]
usb_serial_generic_write_start [usbserial]
Allocated by task 139:
usb_serial_probe [usbserial]
The buggy address is located 2 bytes inside of allocated 64-byte region
The out-of-bounds write no longer occurs with this change applied.
In the Linux kernel, the following vulnerability has been resolved:
USB: serial: io_ti: fix heap overflow in build_i2c_fw_hdr()
build_i2c_fw_hdr() allocates a fixed-size buffer of
(16*1024 - 512) + sizeof(struct ti_i2c_firmware_rec) bytes, then
copies le16_to_cpu(img_header->Length) bytes into it without
validating that Length fits within the available space after the
firmware record header.
img_header->Length is a __le16 from the firmware file and can be
up to 65535. check_fw_sanity() validates the total firmware size
but not img_header->Length specifically.
Fix by rejecting images where img_header->Length exceeds the
available destination space.
In the Linux kernel, the following vulnerability has been resolved:
bnxt_en: Fix NULL pointer dereference
PCIe errors detected by a Root Port or Downstream Port cause error
recovery services to run on all subordinate devices regardless of
administrative state.
The .error_detected() callback, bnxt_io_error_detected(), disables
and synchronizes IRQs via bnxt_disable_int_sync(), which calls
bnxt_cp_num_to_irq_num() to map completion rings to IRQs using
bp->bnapi.
Since bp->bnapi is allocated on NIC open and freed on NIC close, PCIe
error recovery on a closed NIC can dereference a NULL pointer.
Check if bp->bnapi is NULL before disabling and synchronizing IRQs.
In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: rtw_mlme: add bounds checks before ie_length subtraction
Add guards to ensure ie_length is large enough before subtracting
fixed IE offsets to prevent unsigned integer underflow.
In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: fix buffer over-read in rtw_update_protection
rtw_update_protection() is called with a pointer offset into the
ies buffer but the full ie_length is passed, causing a potential
buffer over-read.