In the Linux kernel, the following vulnerability has been resolved:
maple_tree: fix mas_empty_area_rev() null pointer dereference
Currently the code calls mas_start() followed by mas_data_end() if the
maple state is MA_START, but mas_start() may return with the maple state
node == NULL. This will lead to a null pointer dereference when checking
information in the NULL node, which is done in mas_data_end().
Avoid setting the offset if there is no node by waiting until after the
maple state is checked for an empty or single entry state.
A user could trigger the events to cause a kernel oops by unmapping all
vmas to produce an empty maple tree, then mapping a vma that would cause
the scenario described above.
In the Linux kernel, the following vulnerability has been resolved:
mm/userfaultfd: reset ptes when close() for wr-protected ones
Userfaultfd unregister includes a step to remove wr-protect bits from all
the relevant pgtable entries, but that only covered an explicit
UFFDIO_UNREGISTER ioctl, not a close() on the userfaultfd itself. Cover
that too. This fixes a WARN trace.
The only user visible side effect is the user can observe leftover
wr-protect bits even if the user close()ed on an userfaultfd when
releasing the last reference of it. However hopefully that should be
harmless, and nothing bad should happen even if so.
This change is now more important after the recent page-table-check
patch we merged in mm-unstable (446dd9ad37d0 ("mm/page_table_check:
support userfault wr-protect entries")), as we'll do sanity check on
uffd-wp bits without vma context. So it's better if we can 100%
guarantee no uffd-wp bit leftovers, to make sure each report will be
valid.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Disable idle reallow as part of command/gpint execution
[Why]
Workaroud for a race condition where DMCUB is in the process of
committing to IPS1 during the handshake causing us to miss the
transition into IPS2 and touch the INBOX1 RPTR causing a HW hang.
[How]
Disable the reallow to ensure that we have enough of a gap between entry
and exit and we're not seeing back-to-back wake_and_executes.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix slab-use-after-free in l2cap_connect()
Extend a critical section to prevent chan from early freeing.
Also make the l2cap_connect() return type void. Nothing is using the
returned value but it is ugly to return a potentially freed pointer.
Making it void will help with backports because earlier kernels did use
the return value. Now the compile will break for kernels where this
patch is not a complete fix.
Call stack summary:
[use]
l2cap_bredr_sig_cmd
l2cap_connect
┌ mutex_lock(&conn->chan_lock);
│ chan = pchan->ops->new_connection(pchan); <- alloc chan
│ __l2cap_chan_add(conn, chan);
│ l2cap_chan_hold(chan);
│ list_add(&chan->list, &conn->chan_l); ... (1)
└ mutex_unlock(&conn->chan_lock);
chan->conf_state ... (4) <- use after free
[free]
l2cap_conn_del
┌ mutex_lock(&conn->chan_lock);
│ foreach chan in conn->chan_l: ... (2)
│ l2cap_chan_put(chan);
│ l2cap_chan_destroy
│ kfree(chan) ... (3) <- chan freed
└ mutex_unlock(&conn->chan_lock);
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read
include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in _test_bit
include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: slab-use-after-free in l2cap_connect+0xa67/0x11a0
net/bluetooth/l2cap_core.c:4260
Read of size 8 at addr ffff88810bf040a0 by task kworker/u3:1/311
In the Linux kernel, the following vulnerability has been resolved:
drm/mediatek: Fix coverity issue with unintentional integer overflow
1. Instead of multiplying 2 variable of different types. Change to
assign a value of one variable and then multiply the other variable.
2. Add a int variable for multiplier calculation instead of calculating
different types multiplier with dma_addr_t variable directly.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix possible out-of-bound read in ath12k_htt_pull_ppdu_stats()
len is extracted from HTT message and could be an unexpected value in
case errors happen, so add validation before using to avoid possible
out-of-bound read in the following message iteration and parsing.
The same issue also applies to ppdu_info->ppdu_stats.common.num_users,
so validate it before using too.
These are found during code review.
Compile test only.
In the Linux kernel, the following vulnerability has been resolved:
cxl/port: Fix delete_endpoint() vs parent unregistration race
The CXL subsystem, at cxl_mem ->probe() time, establishes a lineage of
ports (struct cxl_port objects) between an endpoint and the root of a
CXL topology. Each port including the endpoint port is attached to the
cxl_port driver.
Given that setup, it follows that when either any port in that lineage
goes through a cxl_port ->remove() event, or the memdev goes through a
cxl_mem ->remove() event. The hierarchy below the removed port, or the
entire hierarchy if the memdev is removed needs to come down.
The delete_endpoint() callback is careful to check whether it is being
called to tear down the hierarchy, or if it is only being called to
teardown the memdev because an ancestor port is going through
->remove().
That care needs to take the device_lock() of the endpoint's parent.
Which requires 2 bugs to be fixed:
1/ A reference on the parent is needed to prevent use-after-free
scenarios like this signature:
BUG: spinlock bad magic on CPU#0, kworker/u56:0/11
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc38 05/24/2023
Workqueue: cxl_port detach_memdev [cxl_core]
RIP: 0010:spin_bug+0x65/0xa0
Call Trace:
do_raw_spin_lock+0x69/0xa0
__mutex_lock+0x695/0xb80
delete_endpoint+0xad/0x150 [cxl_core]
devres_release_all+0xb8/0x110
device_unbind_cleanup+0xe/0x70
device_release_driver_internal+0x1d2/0x210
detach_memdev+0x15/0x20 [cxl_core]
process_one_work+0x1e3/0x4c0
worker_thread+0x1dd/0x3d0
2/ In the case of RCH topologies, the parent device that needs to be
locked is not always @port->dev as returned by cxl_mem_find_port(), use
endpoint->dev.parent instead.
In the Linux kernel, the following vulnerability has been resolved:
riscv: VMAP_STACK overflow detection thread-safe
commit 31da94c25aea ("riscv: add VMAP_STACK overflow detection") added
support for CONFIG_VMAP_STACK. If overflow is detected, CPU switches to
`shadow_stack` temporarily before switching finally to per-cpu
`overflow_stack`.
If two CPUs/harts are racing and end up in over flowing kernel stack, one
or both will end up corrupting each other state because `shadow_stack` is
not per-cpu. This patch optimizes per-cpu overflow stack switch by
directly picking per-cpu `overflow_stack` and gets rid of `shadow_stack`.
Following are the changes in this patch
- Defines an asm macro to obtain per-cpu symbols in destination
register.
- In entry.S, when overflow is detected, per-cpu overflow stack is
located using per-cpu asm macro. Computing per-cpu symbol requires
a temporary register. x31 is saved away into CSR_SCRATCH
(CSR_SCRATCH is anyways zero since we're in kernel).
Please see Links for additional relevant disccussion and alternative
solution.
Tested by `echo EXHAUST_STACK > /sys/kernel/debug/provoke-crash/DIRECT`
Kernel crash log below
Insufficient stack space to handle exception!/debug/provoke-crash/DIRECT
Task stack: [0xff20000010a98000..0xff20000010a9c000]
Overflow stack: [0xff600001f7d98370..0xff600001f7d99370]
CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34
Hardware name: riscv-virtio,qemu (DT)
epc : __memset+0x60/0xfc
ra : recursive_loop+0x48/0xc6 [lkdtm]
epc : ffffffff808de0e4 ra : ffffffff0163a752 sp : ff20000010a97e80
gp : ffffffff815c0330 tp : ff600000820ea280 t0 : ff20000010a97e88
t1 : 000000000000002e t2 : 3233206874706564 s0 : ff20000010a982b0
s1 : 0000000000000012 a0 : ff20000010a97e88 a1 : 0000000000000000
a2 : 0000000000000400 a3 : ff20000010a98288 a4 : 0000000000000000
a5 : 0000000000000000 a6 : fffffffffffe43f0 a7 : 00007fffffffffff
s2 : ff20000010a97e88 s3 : ffffffff01644680 s4 : ff20000010a9be90
s5 : ff600000842ba6c0 s6 : 00aaaaaac29e42b0 s7 : 00fffffff0aa3684
s8 : 00aaaaaac2978040 s9 : 0000000000000065 s10: 00ffffff8a7cad10
s11: 00ffffff8a76a4e0 t3 : ffffffff815dbaf4 t4 : ffffffff815dbaf4
t5 : ffffffff815dbab8 t6 : ff20000010a9bb48
status: 0000000200000120 badaddr: ff20000010a97e88 cause: 000000000000000f
Kernel panic - not syncing: Kernel stack overflow
CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffff80006754>] dump_backtrace+0x30/0x38
[<ffffffff808de798>] show_stack+0x40/0x4c
[<ffffffff808ea2a8>] dump_stack_lvl+0x44/0x5c
[<ffffffff808ea2d8>] dump_stack+0x18/0x20
[<ffffffff808dec06>] panic+0x126/0x2fe
[<ffffffff800065ea>] walk_stackframe+0x0/0xf0
[<ffffffff0163a752>] recursive_loop+0x48/0xc6 [lkdtm]
SMP: stopping secondary CPUs
---[ end Kernel panic - not syncing: Kernel stack overflow ]---