| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: hyper-v: Clamp stimer deadline to avoid livelock
Fix an issue where userspace or the guest can program an Hyper-V
synthetic timer to have a deadline in the past via integer overflow,
preventing the CPU from making progress and triggering an RCU stall.
Hyper-V's SynIC exposes 4 per-vCPU synthetic timers to the
guest, which are emulated by KVM. Each is programmed through the
HV_X64_MSR_STIMERi_CONFIG and HV_X64_MSR_STIMERi_COUNT MSRs. Depending
on CONFIG, COUNT represents either the absolute expiration time or the
period of a periodic timer, both expressed in 100ns ticks. These timers
may be set both by the guest (WRMSR) and the host (KVM_SET_MSRS).
When the timer is enabled, stimer_start() translates COUNT to an
absolute monotonic deadline and arms an hrtimer. If COUNT is set to a
value close to U64_MAX, the deadline calculation can overflow.
ktime_add_ns(ktime_now, 100 * (stimer->exp_time - time_now))
This can result in a CPU livelock. stimer_start() arms the timer
via hrtimer_start() with a deadline in the past, which causes it to
immediately fire. The stimer callback then raises KVM_RQ_HV_STIMER, with
the intention of causing KVM to deliver a synthetic interrupt on the
next vCPU guest enter.
Then, once userspace issues KVM_RUN, vcpu_enter_guest() consumes the
request, calling kvm_hv_process_stimers(). This would normally disable
the timer via stimer_expiration() once the deadline is in the past.
However, the deadline comparison is done between the KVM reference
counter and stime->exp_time, which is a big value close to U64_MAX, so
this never happens for a few thousand years.
kvm_hv_process_timers() then re-arms the timer via stimer_start(), since
it was not disabled, which again fires immediately. Before entering
the guest, kvm_vcpu_exit_request() checks kvm_request_pending(),
which returns true due to the newly raised KVM_REQ_HV_STIMER. Then
vcpu_enter_guest() aborts the guest entry, returning early into
vcpu_run(), which loops back again into vcpu_enter_guest(), restarting
the cycle.
Since there are no manual yields in this loop, a task with SCHED_FIFO
may starve RCU grace-period kthreads, which exposes the stalls found
by syzcaller:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: (detected by 1, t=10502 jiffies, g=14269, q=1142 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10500 (4294965239-4294954739), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10500 jiffies! g14269 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
( ... )
Call Trace:
<IRQ>
__run_hrtimer kernel/time/hrtimer.c:1773 [inline]
__hrtimer_run_queues+0x408/0xc30 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 0b f4 5f f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 23 6b 27 f6 65 8b 05 7c 60 5a 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc900040a7320 EFLAGS: 00000206
RAX: 5de15cb931505900 RBX: 0000000000000a06 RCX: 5de15cb931505900
RDX: 0000000000000007 RSI: ffffffff8daa9dc3 RDI: 0000000000000001
RBP: ffffc900040a73b0 R08: ffffffff8fc3d0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Take srcu when importing watchpoint data
__import_wp_info() backs up the original guest memory contents of a
watchpoint with read_guest_abs(), which is kvm_read_guest() and therefore
resolves the memslot via __kvm_memslots(). That requires kvm->srcu (or
kvm->slots_lock) to be held, otherwise a concurrent memslot update can
free the memslots array under us once its SRCU grace period has elapsed.
As this is not fast path, following lock ordering (mutex first, then
srcu) take the big hammer and hold the srcu for the full import. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Fix memory corruption by not reinjecting CK machine checks
Channel-subsystem damage machine checks are for the host channel
subsystem. The guest channel subsystem is emulated in the userspace VMM.
There is no point in forwarding such machine checks into the guest.
This also simplifies the machine check reinjection and avoids kfree of a
stack variable as reported by sashiko. There might be still machine
checks that have the ck bit set with another bit (like instruction
damage), mask out the CK bit in s390_backup_mcck_info(), like the CP and
ED bits already are. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: keyop: use mmu_lock to read gmap->asce
Every other dat_* consumer in this file (kvm_s390_get_skeys,
set_skeys, get_cmma_bits, set_cmma_bits, MEM_CLR_CMMA,
kvm_s390_fixup_prefix, kvm_test_age_gfn, kvm_age_gfn) reads
kvm->arch.gmap->asce *inside* the mmu_lock read-side. keyop is the only
outlier.
gmap->asce is mutated under write_lock(mmu_lock) by gmap_set_limit()
and keyop might use a stale asce value for walking as KVM_S390_KEYOP
and KVM_S390_VM_MEM_LIMIT_SIZE can run concurrently. This can result
in memory corruption. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Correctly handle end of VA space TLBI invalidation
Our TLB invalidation by VA code is based on comparing two ranges,
one defined by the TLB, and one defined by the TLBI instruction.
Each range is defined by a start and a size. However, the way the
comparison is done doesn't account for address rollover, as it
compares an address with (base + size). This works nicely until
this expression represent the last page/block in the TTBR1 VA space,
as the result is a big fat 0. And a failed TLB invalidation.
Rewrite the comparison in a way that is immune to the address
rollover (making the end address inclusive instead of exclusive),
and move this into a common helper that is used by both VA and IPA
invalidations, as suggested by Hyunwoo Kim (although the IPA version
didn't suffer from this particular problem, obviously). |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry
A VNCR TLB invalidation can occur on one vcpu while another vcpu is
faulting in this same page. Without correctly handling this, we can
end up with the following scenario:
- vcpu A walks the PTs to translate VNCR
- before vcpu A is able to grab the MMU lock to insert the TLB,
vcpu B updates the S1 PTs with an invalid entry, and issues
a TLBI S1E2 for this VA
- vcpu A inserts the TLB for something that is now invalid
This isn't a new problem, and we manage S2 by having the MMU notifier
to bump up mmu_invalidate_seq on invalidation so that the fault can be
replayed.
We can perform something similar here, and extend invalidate_vncr_va() to
update the same counter, clearly indicating that the context has
changed under our feet. This is safe as the invalidation always happen
while holding the MMU lock for write, and that we sample the sequence
number before walking S1. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Remove VM-wide VNCR mapping counter
The global VNCR mapping counter is used to decide whether an L1
provided VNCR page is mapped in L0 on any CPU at the point of
dealing with a TLB invalidation. It is incremented when a mapping
is made in the fixmap, and decremented when unmapped.
As it turns out, this tracking has several flaws:
- we are trying to invalidate TLBs, and the mapping is only an
opportunistic consequence of the TLB. Checking this counter to
decide whether a TLB needs to be invalidated may result in missed
invalidations.
- an L1 vcpu invalidating its own TLB (a very likely case) will not
succeed in invalidating the VNCR pseudo TLB because that page is
not mapped in L0 at this stage.
Given that this tracking fails at delivering the minimum guarantees
that are required and is only a performance optimisation, remove it
completely. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Sign-extend VA for range-based TLBI invalidation
When the decode_range_tlbi() helper was moved to be used for S1 TLBIs,
the required sign extension was omitted. Add it.
As a result, special care must be taken to not overflow PA bits when
this is used for S2 invalidation. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: vgic-v3: take an LPI reference in vgic_v3_save_pending_tables
vgic_v3_save_pending_tables() iterates dist->lpi_xa using xa_for_each()
and dereferences the returned struct vgic_irq in the loop body without
holding a reference on the LPI.
The xarray iterator only provides temporary RCU coverage while looking up
the current entry. That is not sufficient for this loop body, which reads
fields from struct vgic_irq and performs guest memory accesses before the
iteration completes.
A concurrent path can trigger this race: the irqfd cached injection path
(vgic_its_inject_cached_translation) obtains a transient LPI reference
via vgic_its_check_cache() without holding kvm->lock, vcpu->mutex,
config_lock, or its_lock. If guest ITS DISCARD then drops the cache and
ITE references under its_lock, the transient inject reference may become
the final one. When vgic_put_irq() drops it, the LPI is erased from
lpi_xa and freed via kfree_rcu(). Meanwhile, vgic_v3_save_pending_tables()
may still hold a stale pointer obtained from the xarray iterator and
dereference it after the RCU grace period completes.
Fix this by re-fetching each iterated LPI via vgic_get_irq(), which takes
a stable reference, and dropping it with vgic_put_irq() on all paths.
This matches the pattern already used by other lpi_xa iterators in the
vgic ITS code. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: vgic-its: Don't dereference a NULL collection on ITT save
MAPC with V=0 drops ite->collection but leaves the ITE on the device's
ITT list, and vgic_its_save_ite() dereferences it unconditionally. A
guest that issues MAPD, MAPTI and then MAPC(V=0) therefore oopses the
host when the VMM issues KVM_DEV_ARM_ITS_SAVE_TABLES to migrate it.
That sequence is UNPREDICTABLE per the architecture, but KVM already
handles the resulting state in the translate, MOVI and DISCARD paths.
Save a zeroed entry, which vgic_its_restore_ite() reads back as
invalid. Skipping the ITE instead would leave the ITT slot holding
whatever is in guest memory, and restore rejects an entry naming a
collection the restored collection table does not have. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Correctly cap TLBI Range to the architural limit
TLB Invalidation by Range has a fairly powerful way of encoding pretty
large ranges in a small number of bits. This range can be based on an
arbitrary VA, which means it is pretty easy for a guest to generate an
overflow should the hypervisor be naive enough to add the range to the
base...
Make sure the range is capped to the limit dictated by the address bit
that determines the VA range. For an IPA invalidation, this is further
corrected down the line to ignore the upper range. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: KVM: Fix uninitialized stack variable issue with dmsintc
Variable vector[] is declared on stack in function dmsintc_inject_irq()
and sometimes it is used without initialized. Here fix this issue. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: KVM: Preserve memslot arch flags on KVM_MR_FLAGS_ONLY
kvm_arch_prepare_memory_region() computes new->arch.flags, i.e. whether
a memslot is KVM_MEM_HUGEPAGE_CAPABLE or KVM_MEM_HUGEPAGE_INCAPABLE,
only for KVM_MR_CREATE and KVM_MR_MOVE, and returns early for every
other change. But the generic code allocates a zeroed memslot for every
change and never copies old->arch, so after a KVM_MR_FLAGS_ONLY update,
e.g. toggling KVM_MEM_LOG_DIRTY_PAGES for live migration, the active
memslot has arch.flags == 0.
With both flags clear, fault_supports_huge_mapping() falls through to
the alignment check on the HVA range alone, which no longer verifies
that the GPA and HVA have the same offset within a PMD. A memslot that
was marked KVM_MEM_HUGEPAGE_INCAPABLE because of a GPA/HVA offset
mismatch can then be mapped with PMD entries on read faults, and since
kvm_map_page() aligns the gfn and the pfn independently, the guest ends
up accessing the wrong host pages, exactly the "d -> f, e -> g" case
described in the comment above the check.
Carry the arch flags over from the old memslot for KVM_MR_FLAGS_ONLY,
as the GPA, HVA and size are guaranteed to be unchanged for that case. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: KVM: Validate MSI data before routing it to EIOINTC
pch_msi_set_irq() passes e->msi.data straight into eiointc_set_irq() as
the irq number. The MSI data comes from userspace, that either via a
KVM_IRQ_ROUTING_MSI entry set with KVM_SET_GSI_ROUTING (used by irqfd
and KVM_IRQ_LINE) or directly via KVM_SIGNAL_MSI, and is never checked
against EIOINTC_IRQS.
eiointc_set_irq() uses the value with __set_bit()/__clear_bit() on the
256-bit isr bitmap, eiointc_update_irq() then indexes sw_coremap[] and
the per-cpu coreisr/sw_coreisr bitmaps with it. Therefore a data value
>= 256 reads and writes memory past the end of those arrays, i.e. any
process holding a VM fd can corrupt kernel memory beyond the allocation
of loongarch_eiointc.
Reject MSI data that doesn't fit in the EIOINTC irq space. The DMSINTC
path is unaffected as it decodes the vector from the address and masks
it. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: BPF: Refactor jump offset calculation in tail call
The old macro-based jmp_offset calculation derives the jump distance
from a stale prior-pass code stride, which can lead to wrong branch
offsets and soft lockups under extra JIT passes.
Fix this by calculating the offset directly on the absolute target:
"ctx->offset[insn + 1] - ctx->idx".
To avoid a false 16-bit range check abort during size estimation, add
a "ctx->image == NULL" guard to inject a safe dummy offset. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Fix acpi_package_ids[] array overflow
With LoongArch virt machine, a typical setting is one core per socket,
there will max 256 sockets (packages) on one VM. With PPTT acpi table,
array acpi_package_ids[] will be overflowed.
Here change the array size of acpi_package_ids[] with the max value of
MAX_PACKAGES and KVM_MAX_VCPUS. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Do not save/restore percpu base register in rethook trampoline
The rethook trampoline saves $r21 ($u0), the percpu base, into its frame
at entry and restores it at exit. Inbetween rethook_trampoline_handler()
may schedule via preempt_enable_notrace().
If the task migrates to another CPU, the frame's $r21 holds the old
CPU's percpu base, and restoring it poisons $r21 on the new CPU. Until
the next user->kernel transition heals $r21, all this_cpu_*() accesses
(runqueues, RCU per-CPU data, timer tick programming, FPU ownership)
hit the wrong CPU's percpu area.
Under kretprobe-heavy preemptible load this can corrupt scheduler and
timer state: scheduling-while-atomic splats, wrong-CPU RCU warnings,
WARN_ON_ONCE(rq != this_rq()) in nohz_balance_exit_idle(), and CPUs
parking in the idle loop with the constant timer never re-armed (hard
lockup). Reproduces on a Loongson-3A6000 with kretprobes on VFS paths
plus heavy file churn (OS install / unsquashfs).
By convention $r21 always holds the current CPU's percpu base in kernel
mode: SAVE_SOME() at exception entry reloads it only when coming from
user mode, and RESTORE_SOME() restores it only when returning to user
mode; the context-switch path never writes it. Therefore the live $r21
at trampoline exit is already correct, and nothing inbetween can change
it legitimately (kernel C code cannot write a global register variable).
The same flaw existed even in the pre-rethook kretprobe trampoline since
v6.3; it was carried over when rethook replaced it. Drop both the save
and the restore here. Drop the restore is enough to solve the issue, and
drop the save is to keep the code tidy and no need to clear it. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Avoid preempt count underflow without probe
LoongArch uses break 11 for the breakpoint placed after an instruction
that Kprobes executes out of line. Since userspace can issue the same
break instruction, do_bp() can reach kprobe_singlestep_handler() when
there is no current probe.
The handler actually returns false in this case, but it first calls
preempt_enable_no_resched(). The corresponding preempt_disable() is done
by kprobe_breakpoint_handler() on a real Kprobe hit, so it has not run
here. As a result, an ordinary userspace breakpoint (code 11) underflows
the current task's preempt count.
This also makes in_interrupt() return true until the task schedules. One
visible consequence is the socket cgroup attribution: cgroup_sk_alloc()
treats the allocation as interrupt context and assigns the socket to the
root cgroup. A socket opened from the SIGTRAP handler can then avoid a
BPF_CGROUP_INET_SOCK_CREATE policy attached to the task's own cgroup.
Return as soon as kprobe_running() reports no active probe.
The same check has appeared in [PATCH v10 2/4] of the original LoongArch
Kprobes series, but was dropped before the feature reached mainline. |
| In the Linux kernel, the following vulnerability has been resolved:
media: cec: disable delayed work before freeing an interrupted transmit
cec_transmit_msg_fh() drops adap->lock to wait for a blocking transmit in
wait_for_completion_killable(). If that wait is interrupted by a signal,
cancel_delayed_work_sync() can run before the CEC kthread arms the reply
timeout via schedule_delayed_work(&data->work) in cec_transmit_done_ts().
The work is then armed after the cancel, and the data is freed with its
delayed_work still pending:
ODEBUG: free active (active state 0) object: ... hint: cec_wait_timeout
Use disable_delayed_work_sync(): it cancels the work and disables it, so
the later schedule_delayed_work() becomes a no-op and the work cannot be
re-armed. The data is freed right after, so it need not be re-enabled. |
| In the Linux kernel, the following vulnerability has been resolved:
media: cec: extron-da-hd-4k-plus: add sanity check
Add check to prevent overflowing msg.msg[] in case the incoming data
is malformed. |
