Высокий · CVSS 8.8EPSS 0,17%Нет опубликованного исправления
KVM: nVMX: Always flush vpid02 on first use
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Always flush vpid02 on first use
Make sure vpid02 is always flushed on first use by setting last_vpid=0
when allocating vpid02. nested_vmx_transition_tlb_flush() will always
detect a VPID change on first VM-Enter after VMXON, because VPID=0 in
vmcs12 is not allowed if L1 enables VPID.
This avoids using stale TLB entries from a previous lifetime of the
VPID, that might have been associated with a different vCPU (or a
completely different VM).
Note that last_vpid is already being initialized as 0 when the vCPU is
created, but it is not reset when vpid02 is freed
Без оценкиEPSS 0,21%Нет опубликованного исправления
KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
Always check and clear KVM_REQ_GET_NESTED_STATE_PAGES when emulating a
nested VM-Exit to ensure the request is cleared, even when KVM was built
with CONFIG_KVM_HYPERV=n, as KVM subtly relies on the "check" to clear
the flag and thus avoid double-mapping the vmcs12 pages, e.g. if KVM
manages to bail from VM-Enter without processing the request, and then
emulates VMLAUNCH or VMRESUME.
KVM: nVMX: Service local TLB flushes on failed nested VM-Enter
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Service local TLB flushes on failed nested VM-Enter
KVM services local TLB flushes on "full" nested VM-Exits (through
__nested_vmx_vmexit()), but not if a nested VM-Enter fails (e.g. due to
failed VMCS checks in nested_vmx_enter_non_root_mode()).
However, it is possible that KVM had queued TLB flushes that need to be
performed, even if the nested VM-Enter was not successful. For example,
if VPID is disabled for L2 (via nested_vmx_transition_tlb_flush(), or if
via the MSR load lists, as the SDM says:
If any MSR is being loaded in such a way that would architec
Высокий · CVSS 8.8EPSS 0,17%Нет опубликованного исправления
KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU
When emulating INVVPID, KVM executes INVVPID on the physical CPU using
vpid02 (instead of the L1 assigned VPID), after doing some validations
on the operands. However, it is possible that the physical CPU KVM
executes INVVPID on is different from the CPU L2 is running on.
For example, in the following scenario:
- L2 runs on CPU #1 and exits to L1 (vmx->nested.vmcs02.cpu=1)
- L1 migrates to CPU #2 and executes INVVPID
- KVM executes INVVPID on CPU #2
- L1 migrates back to CPU #1 and runs L2 (vmx->nested.vmcs02
Высокий · CVSS 8.8EPSS 0,17%Нет опубликованного исправления
KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk
__kvm_rmap_lock() deliberately elides the rmap lock when it observes an
empty rmap. In that case kvm_rmap_lock_readonly() also re-enables
preemption and returns zero, so the caller holds neither the rmap lock
nor a preemption reference. The elision documents the invariant it
relies on:
* Elide the lock if the rmap is empty, as lockless walkers (read-only
* mode) don't need to (and can't) walk an empty rmap, nor can they add
* entries to the rmap. I.e. the only paths that process empty rmaps
*
Высокий · CVSS 7.1EPSS 0,18%Нет опубликованного исправления
KVM: x86: hyper-v: Clamp stimer deadline to avoid livelock
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
Без оценкиEPSS 0,21%Нет опубликованного исправления
KVM: s390: Fix length check __import_wp_info()
In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Fix length check __import_wp_info()
struct kvm_hw_breakpoint::len is a __u64 that is fully controlled by user
space. This is then assigned to wp_info->len, which is an int. The bounds
check is done on the truncated value while the allocation uses the
untruncated one:
wp_info->len = bp_data->len;
[...]
if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE)
return -EINVAL;
wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL_ACCOUNT);
Use the validated value for the allocation as intended. Without this
fix userspace can trigger >4GB allocations which will fai
Без оценкиEPSS 0,21%Нет опубликованного исправления
KVM: s390: Fix memory leak in guest debug handling
In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Fix memory leak in guest debug handling
bp_data is freed only for the error case by kfree(bp_data).
Every successful KVM_SET_GUEST_DEBUG will leak bp_data.
Без оценкиEPSS 0,22%Нет опубликованного исправления
KVM: s390: Fix old_data leak in guest debug error path
In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Fix old_data leak in guest debug error path
__import_wp_info() allocates a per-watchpoint old_data buffer to back up
the original guest memory contents. If a later watchpoint of the same
KVM_SET_GUEST_DEBUG request fails to import, kvm_s390_import_bp_data()
jumps to the error label, which frees the wp_info array but not the
old_data buffers of the entries that were imported successfully. Up to
MAX_BP_COUNT - 1 buffers of up to MAX_WP_SIZE bytes are leaked per failed
request, and the request can be repeated.
Create error handling for cleaning up all created old_d
Без оценкиEPSS 0,21%Нет опубликованного исправления
KVM: s390: Free guest debug data on vcpu destroy
In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Free guest debug data on vcpu destroy
kvm_s390_clear_bp_data() is only called from
kvm_arch_vcpu_ioctl_set_guest_debug(), i.e. when user space changes or
disables debugging. A vCPU that is destroyed while hardware breakpoints
are still armed - the normal case when the VMM just exits or crashes -
leaks hw_bp_info, hw_wp_info and all old_data buffers, since generic KVM
frees the vCPU right after kvm_arch_vcpu_destroy().
That is bounded by MAX_BP_COUNT entries, so roughly 8 KiB per vCPU, but
it is unbounded over VM lifetimes. The allocations are
GFP_KERNEL_ACCOUNT,
Высокий · CVSS 7.8EPSS 0,16%Нет опубликованного исправления
KVM: s390: Take srcu when importing watchpoint data
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.
KVM: s390: Zero initialize data structures for inject_pfault_token
In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Zero initialize data structures for inject_pfault_token
__kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of
the on-stack struct kvm_s390_irq but the full ext substructure is copied
into the cpu local variable on inject. ext_params and pad contain stale
stack values.
Interrupt delivery only uses ext_params2, so nothing leaks to the guest,
but a host user can use the migration ioctls to get to the data.
Fix by zero-initializing the irq struct.
Do the same for the inti data structure.
Высокий · CVSS 7.8EPSS 0,18%Нет опубликованного исправления
KVM: s390: Fix memory corruption by not reinjecting CK machine checks
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.
KVM: arm64: Correctly handle end of VA space TLBI invalidation
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
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Handle VNCR TLB invalidation race with vcpu_put() VNCR unmapping
While VNCR TLB invalidation always occurs under the MMU lock,
vcpu_put() doesn't, while it unmaps the VNCR page.
The problem is that the invalidation evaluates vncr_tlb::cpu to
decide whether an unmapping needs to take place (cpu != -1) before
performing it. On the other hand, this_cpu_reset_vncr_fixmap()
unconditionally unmaps if L1_VNCR_MAPPED is set.
These two obviously can race, with a TOCTOU pattern on the TLBI
path, and a BUG_ON() on the vcpu_put() path. And the two can end-up
calling vncr_
KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry
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
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 invalid
KVM: arm64: Sign-extend VA for range-based TLBI invalidation
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.
Высокий · CVSS 8.8EPSS 0,18%Нет опубликованного исправления
KVM: arm64: vgic-v3: take an LPI reference in vgic_v3_save_pending_tables
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_inj
Высокий · CVSS 7.1EPSS 0,18%Нет опубликованного исправления
KVM: arm64: vgic-its: Don't dereference a NULL collection on ITT save
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 in