| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: Reject wrapped offset in kvm_reset_dirty_gfn()
kvm_reset_dirty_gfn() guards the gfn range with
if (!memslot || (offset + __fls(mask)) >= memslot->npages)
return;
but offset is u64 and the addition is unchecked. The check can be
silently bypassed by a u64 wrap.
The dirty ring backing those entries is MAP_SHARED at
KVM_DIRTY_LOG_PAGE_OFFSET of the vcpu fd, so the VMM can rewrite the
slot and offset fields of any entry between when the kernel pushes
them and when KVM_RESET_DIRTY_RINGS consumes them. On reset,
kvm_dirty_ring_reset() re-reads the values via READ_ONCE() and feeds
them straight back into this check; only the flags handshake is
treated as the handover, the slot/offset payload is taken on trust.
Crafting two entries
entry[i].offset = 0xffffffffffffffc1
entry[i+1].offset = 0
makes the coalescing loop in kvm_dirty_ring_reset() compute
delta = (s64)(0 - 0xffffffffffffffc1) = 63
which falls in [0, BITS_PER_LONG), so it folds entry[i+1] into the
existing mask by setting bit 63. The trailing kvm_reset_dirty_gfn()
call then sees offset = 0xffffffffffffffc1 and __fls(mask) = 63;
the sum is 0 in u64 and the bounds check passes.
That offset propagates into kvm_arch_mmu_enable_log_dirty_pt_masked()
unchanged. On the legacy MMU path -- kvm_memslots_have_rmaps() ==
true, i.e. shadow paging, any VM that has allocated shadow roots, or
a write-tracked slot -- it reaches gfn_to_rmap(), which indexes
slot->arch.rmap[0][] with a near-U64_MAX gfn. That is an
out-of-bounds load of a kvm_rmap_head, followed by a conditional
clear of PT_WRITABLE_MASK in whatever the loaded pointer points at.
The path is reachable from any process holding /dev/kvm.
Range-check offset on its own first, so the addition cannot wrap.
memslot->npages is bounded well below U64_MAX, so once offset <
npages holds, offset + __fls(mask) (with __fls(mask) < BITS_PER_LONG)
stays in range. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: Don't clobber irqfd routing type when deassigning irqfd
When deassigning a KVM_IRQFD, don't clobber the irqfd's copy of the IRQ's
routing entry as doing so breaks kvm_arch_irq_bypass_del_producer() on x86
and arm64, which explicitly look for KVM_IRQ_ROUTING_MSI. Instead, to
handle a concurrent routing update, verify that the irqfd is still active
before consuming the routing information. As evidenced by the x86 and
arm64 bugs, and another bug in kvm_arch_update_irqfd_routing() (see below),
clobbering the entry type without notifying arch code is surprising and
error prone.
As a bonus, checking that the irqfd is active provides a convenient
location for documenting _why_ KVM must not consume the routing entry for
an irqfd that is in the process of being deassigned: once the irqfd is
deleted from the list (which happens *before* the eventfd is detached), it
will no longer receive updates via kvm_irq_routing_update(), and so KVM
could deliver an event using stale routing information (relative to
KVM_SET_GSI_ROUTING returning to userspace).
As an even better bonus, explicitly checking for the irqfd being active
fixes a similar bug to the one the clobbering is trying to prevent: if an
irqfd is deactivated, and then its routing is changed,
kvm_irq_routing_update() won't invoke kvm_arch_update_irqfd_routing()
(because the irqfd isn't in the list). And so if the irqfd is in bypass
mode, IRQs will continue to be posted using the old routing information.
As for kvm_arch_irq_bypass_del_producer(), clobbering the routing type
results in KVM incorrectly keeping the IRQ in bypass mode, which is
especially problematic on AMD as KVM tracks IRQs that are being posted to
a vCPU in a list whose lifetime is tied to the irqfd.
Without the help of KASAN to detect use-after-free, the most common
sympton on AMD is a NULL pointer deref in amd_iommu_update_ga() due to
the memory for irqfd structure being re-allocated and zeroed, resulting
in irqfd->irq_bypass_data being NULL when read by
avic_update_iommu_vcpu_affinity():
BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 40cf2b9067 P4D 40cf2b9067 PUD 408362a067 PMD 0
Oops: Oops: 0000 [#1] SMP
CPU: 6 UID: 0 PID: 40383 Comm: vfio_irq_test
Tainted: G U W O 6.19.0-smp--5dddc257e6b2-irqfd #31 NONE
Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE
Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 34.78.2-0 09/05/2025
RIP: 0010:amd_iommu_update_ga+0x19/0xe0
Call Trace:
<TASK>
avic_update_iommu_vcpu_affinity+0x3d/0x90 [kvm_amd]
__avic_vcpu_load+0xf4/0x130 [kvm_amd]
kvm_arch_vcpu_load+0x89/0x210 [kvm]
vcpu_load+0x30/0x40 [kvm]
kvm_arch_vcpu_ioctl_run+0x45/0x620 [kvm]
kvm_vcpu_ioctl+0x571/0x6a0 [kvm]
__se_sys_ioctl+0x6d/0xb0
do_syscall_64+0x6f/0x9d0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x46893b
</TASK>
---[ end trace 0000000000000000 ]---
If AVIC is inhibited when the irfd is deassigned, the bug will manifest as
list corruption, e.g. on the next irqfd assignment.
list_add corruption. next->prev should be prev (ffff8d474d5cd588),
but was 0000000000000000. (next=ffff8d8658f86530).
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:31!
Oops: invalid opcode: 0000 [#1] SMP
CPU: 128 UID: 0 PID: 80818 Comm: vfio_irq_test
Tainted: G U W O 6.19.0-smp--f19dc4d680ba-irqfd #28 NONE
Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE
Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 34.78.2-0 09/05/2025
RIP: 0010:__list_add_valid_or_report+0x97/0xc0
Call Trace:
<TASK>
avic_pi_update_irte+0x28e/0x2b0 [kvm_amd]
kvm_pi_update_irte+0xbf/0x190 [kvm]
kvm_arch_irq_bypass_add_producer+0x72/0x90 [kvm]
irq_bypass_register_consumer+0xcd/0x170 [irqbypa
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
nfs4_setup_readdir(): insufficient locking for ->d_parent->d_inode dereferencing
Theoretically it's an oopsable race, but I don't believe one can manage
to hit it on real hardware; might become doable on a KVM, but it still
won't be easy to attack.
Anyway, it's easy to deal with - since xdr_encode_hyper() is just a call of
put_unaligned_be64(), we can put that under ->d_lock and be done with that. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Add missing save/restore handling of LBR MSRs
MSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by
KVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So
save/restore is completely broken.
Fix it by adding the MSRs to msrs_to_save_base, and allowing writes to
LBR MSRs from userspace only (as they are read-only MSRs) if LBR
virtualization is enabled. Additionally, to correctly restore L1's LBRs
while L2 is running, make sure the LBRs are copied from the captured
VMCB01 save area in svm_copy_vmrun_state().
Note, for VMX, this also fixes a flaw where MSR_IA32_DEBUGCTLMSR isn't
reported as an MSR to save/restore.
Note #2, over-reporting MSR_IA32_LASTxxx on Intel is ok, as KVM already
handles unsupported reads and writes thanks to commit b5e2fec0ebc3 ("KVM:
Ignore DEBUGCTL MSRs with no effect") (kvm_do_msr_access() will morph the
unsupported userspace write into a nop).
[sean: guard with lbrv checks, massage changelog] |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2
After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs
fields written by the CPU from vmcb02 to the cached vmcb12. This is
because the cached vmcb12 is used as the authoritative copy of some of
the controls, and is the payload when saving/restoring nested state.
int_state is also written by the CPU, specifically bit 0 (i.e.
SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to
cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE
preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow
would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites
what KVM_SET_NESTED_STATE restored in int_state).
However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an
interrupt shadow would be restored into vmcb01 instead of vmcb02. This
would mostly be benign for L1 (delays an interrupt), but not for L2. For
L2, the vCPU could hang (e.g. if a wakeup interrupt is delivered before
a HLT that should have been in an interrupt shadow).
Sync int_state to the cached vmcb12 in nested_sync_control_from_vmcb02()
to avoid this problem. With that, KVM_SET_NESTED_STATE restores the
correct interrupt shadow state, and if KVM_SET_VCPU_EVENTS follows it
would overwrite it with the same value. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Always use NextRIP as vmcb02's NextRIP after first L2 VMRUN
For guests with NRIPS disabled, L1 does not provide NextRIP when running
an L2 with an injected soft interrupt, instead it advances the current RIP
before running it. KVM uses the current RIP as the NextRIP in vmcb02 to
emulate a CPU without NRIPS.
However, after L2 runs the first time, NextRIP will be updated by the CPU
and/or KVM, and the current RIP is no longer the correct value to use in
vmcb02. Hence, after save/restore, use the current RIP if and only if a
nested run is pending, otherwise use NextRIP. Give soft_int_next_rip the
same treatment, as it's the same logic, just for a narrower use case.
[sean: give soft_int_next_rip the same treatment] |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Reassign nested_mmus array behind mmu_lock
kvm->arch.nested_mmus[] is walked under kvm->mmu_lock, including from the
MMU notifier path (kvm_unmap_gfn_range() -> kvm_nested_s2_unmap()), which
can run at any time. kvm_vcpu_init_nested() reallocates the array and frees
the old buffer while holding only kvm->arch.config_lock, so such a walker
can reference the freed array.
Allocate the new array outside of mmu_lock, as the allocation can sleep.
Under the lock, copy the existing entries, fix up the back pointers and
reassign the array. Free the old buffer after dropping the lock, as
kvfree() can sleep as well. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: vgic-its: Drop the translation cache reference only for the erased entry
vgic_its_invalidate_cache() walks the per-ITS translation cache with
xa_for_each() and drops the cache's reference on each entry with
vgic_put_irq(). It puts the iterated pointer, though, rather than the
value returned by xa_erase().
The function is called from contexts that do not exclude one another: the
ITS command handlers hold its_lock, the GITS_CTLR write path holds
cmd_lock, and the path that clears EnableLPIs in a redistributor's
GICR_CTLR holds neither. Two or more of them can drain the same cache
concurrently, and if each one observes the same entry, erases it and then
puts it, the single reference the cache holds on that entry is dropped
more than once. The entry can then be freed while an ITE still maps it.
xa_erase() is atomic and returns the previous entry, so put only the entry
that this context actually removed. The cache reference is then dropped
exactly once per entry even when the invalidations run concurrently, and
the behavior is unchanged when only one context runs. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Do not register unsupported perf events
Synthetic events currently do not have a function to register perf events.
This leads to calling the tracepoint register functions with a NULL
function pointer which triggers:
------------[ cut here ]------------
WARNING: kernel/tracepoint.c:175 at tracepoint_add_func+0x357/0x370, CPU#2: perf/2272
Modules linked in: kvm_intel kvm irqbypass
CPU: 2 UID: 0 PID: 2272 Comm: perf Not tainted 6.18.0-ftest-11964-ge022764176fc-dirty #323 PREEMPTLAZY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:tracepoint_add_func+0x357/0x370
Code: 28 9c e8 4c 0b f5 ff eb 0f 4c 89 f7 48 c7 c6 80 4d 28 9c e8 ab 89 f4 ff 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc <0f> 0b 49 c7 c6 ea ff ff ff e9 ee fe ff ff 0f 0b e9 f9 fe ff ff 0f
RSP: 0018:ffffabc0c44d3c40 EFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff9380aa9e4060 RCX: 0000000000000000
RDX: 000000000000000a RSI: ffffffff9e1d4a98 RDI: ffff937fcf5fd6c8
RBP: 0000000000000001 R08: 0000000000000007 R09: ffff937fcf5fc780
R10: 0000000000000003 R11: ffffffff9c193910 R12: 000000000000000a
R13: ffffffff9e1e5888 R14: 0000000000000000 R15: ffffabc0c44d3c78
FS: 00007f6202f5f340(0000) GS:ffff93819f00f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d3162281a8 CR3: 0000000106a56003 CR4: 0000000000172ef0
Call Trace:
<TASK>
tracepoint_probe_register+0x5d/0x90
synth_event_reg+0x3c/0x60
perf_trace_event_init+0x204/0x340
perf_trace_init+0x85/0xd0
perf_tp_event_init+0x2e/0x50
perf_try_init_event+0x6f/0x230
? perf_event_alloc+0x4bb/0xdc0
perf_event_alloc+0x65a/0xdc0
__se_sys_perf_event_open+0x290/0x9f0
do_syscall_64+0x93/0x7b0
? entry_SYSCALL_64_after_hwframe+0x76/0x7e
? trace_hardirqs_off+0x53/0xc0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Instead, have the code return -ENODEV, which doesn't warn and has perf
error out with:
# perf record -e synthetic:futex_wait
Error:
The sys_perf_event_open() syscall returned with 19 (No such device) for event (synthetic:futex_wait).
"dmesg | grep -i perf" may provide additional information.
Ideally perf should support synthetic events, but for now just fix the
warning. The support can come later. |
| In the Linux kernel, the following vulnerability has been resolved:
riscv: kvm: fix vector context allocation leak
When the second kzalloc (host_context.vector.datap) fails in
kvm_riscv_vcpu_alloc_vector_context, the first allocation
(guest_context.vector.datap) is leaked. Free it before returning. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Fix pin leak and publication ordering in __pkvm_init_vcpu()
Two bugs exist in the vCPU initialisation path:
1. If a check fails after hyp_pin_shared_mem() succeeds, the cleanup
path jumps to 'unlock' without calling unpin_host_vcpu() or
unpin_host_sve_state(), permanently leaking pin references on the
host vCPU and SVE state pages.
Extract a register_hyp_vcpu() helper that performs the checks and
the store. When register_hyp_vcpu() returns an error, call
unpin_host_vcpu() and unpin_host_sve_state() inline before falling
through to the existing 'unlock' label.
2. register_hyp_vcpu() publishes the new vCPU pointer into
'hyp_vm->vcpus[]' with a bare store, allowing a concurrent caller
of pkvm_load_hyp_vcpu() to observe a partially initialised vCPU
object.
Ensure the store uses smp_store_release() and the load uses
smp_load_acquire(). While 'vm_table_lock' currently serialises the
store and the load, these barriers ensure the reader sees the fully
initialised 'hyp_vcpu' object even if there were a lockless path or
if the lock's own ordering guarantees were insufficient for nested
object initialization. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/alloc_tag: clear codetag for pages allocated before page_ext initialization
Due to initialization ordering, page_ext is allocated and initialized
relatively late during boot. Some pages have already been allocated and
freed before page_ext becomes available, leaving their codetag
uninitialized.
A clear example is in init_section_page_ext(): alloc_page_ext() calls
kmemleak_alloc(). If the slab cache has no free objects, it falls back to
the buddy allocator to allocate memory. However, at this point page_ext
is not yet fully initialized, so these newly allocated pages have no
codetag set. These pages may later be reclaimed by KASAN, which causes
the warning to trigger when they are freed because their codetag ref is
still empty.
Use a global array to track pages allocated before page_ext is fully
initialized. The array size is fixed at 8192 entries, and will emit a
warning if this limit is exceeded. When page_ext initialization
completes, set their codetag to empty to avoid warnings when they are
freed later.
This warning is only observed with CONFIG_MEM_ALLOC_PROFILING_DEBUG=Y and
mem_profiling_compressed disabled:
[ 9.582133] ------------[ cut here ]------------
[ 9.582137] alloc_tag was not set
[ 9.582139] WARNING: ./include/linux/alloc_tag.h:164 at __pgalloc_tag_sub+0x40f/0x550, CPU#5: systemd/1
[ 9.582190] CPU: 5 UID: 0 PID: 1 Comm: systemd Not tainted 7.0.0-rc4 #1 PREEMPT(lazy)
[ 9.582192] Hardware name: Red Hat KVM, BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 9.582194] RIP: 0010:__pgalloc_tag_sub+0x40f/0x550
[ 9.582196] Code: 00 00 4c 29 e5 48 8b 05 1f 88 56 05 48 8d 4c ad 00 48 8d 2c c8 e9 87 fd ff ff 0f 0b 0f 0b e9 f3 fe ff ff 48 8d 3d 61 2f ed 03 <67> 48 0f b9 3a e9 b3 fd ff ff 0f 0b eb e4 e8 5e cd 14 02 4c 89 c7
[ 9.582197] RSP: 0018:ffffc9000001f940 EFLAGS: 00010246
[ 9.582200] RAX: dffffc0000000000 RBX: 1ffff92000003f2b RCX: 1ffff110200d806c
[ 9.582201] RDX: ffff8881006c0360 RSI: 0000000000000004 RDI: ffffffff9bc7b460
[ 9.582202] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff3a62324
[ 9.582203] R10: ffffffff9d311923 R11: 0000000000000000 R12: ffffea0004001b00
[ 9.582204] R13: 0000000000002000 R14: ffffea0000000000 R15: ffff8881006c0360
[ 9.582206] FS: 00007ffbbcf2d940(0000) GS:ffff888450479000(0000) knlGS:0000000000000000
[ 9.582208] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9.582210] CR2: 000055ee3aa260d0 CR3: 0000000148b67005 CR4: 0000000000770ef0
[ 9.582211] PKRU: 55555554
[ 9.582212] Call Trace:
[ 9.582213] <TASK>
[ 9.582214] ? __pfx___pgalloc_tag_sub+0x10/0x10
[ 9.582216] ? check_bytes_and_report+0x68/0x140
[ 9.582219] __free_frozen_pages+0x2e4/0x1150
[ 9.582221] ? __free_slab+0xc2/0x2b0
[ 9.582224] qlist_free_all+0x4c/0xf0
[ 9.582227] kasan_quarantine_reduce+0x15d/0x180
[ 9.582229] __kasan_slab_alloc+0x69/0x90
[ 9.582232] kmem_cache_alloc_noprof+0x14a/0x500
[ 9.582234] do_getname+0x96/0x310
[ 9.582237] do_readlinkat+0x91/0x2f0
[ 9.582239] ? __pfx_do_readlinkat+0x10/0x10
[ 9.582240] ? get_random_bytes_user+0x1df/0x2c0
[ 9.582244] __x64_sys_readlinkat+0x96/0x100
[ 9.582246] do_syscall_64+0xce/0x650
[ 9.582250] ? __x64_sys_getrandom+0x13a/0x1e0
[ 9.582252] ? __pfx___x64_sys_getrandom+0x10/0x10
[ 9.582254] ? do_syscall_64+0x114/0x650
[ 9.582255] ? ksys_read+0xfc/0x1d0
[ 9.582258] ? __pfx_ksys_read+0x10/0x10
[ 9.582260] ? do_syscall_64+0x114/0x650
[ 9.582262] ? do_syscall_64+0x114/0x650
[ 9.582264] ? __pfx_fput_close_sync+0x10/0x10
[ 9.582266] ? file_close_fd_locked+0x178/0x2a0
[ 9.582268] ? __x64_sys_faccessat2+0x96/0x100
[ 9.582269] ? __x64_sys_close+0x7d/0xd0
[ 9.582271] ? do_syscall_64+0x114/0x650
[ 9.582273] ? do_syscall_64+0x114/0x650
[ 9.582275] ? clear_bhb_loop+0x50/0xa0
[ 9.582277] ? clear_bhb_l
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: Do IRR scan in __kvm_apic_update_irr even if PIR is empty
Fall back to apic_find_highest_vector() when PID.ON is set but PIR
turns out to be empty, to correctly report the highest pending interrupt
from the existing IRR.
In a nested VM stress test, the following WARNING fires in
vmx_check_nested_events() when kvm_cpu_has_interrupt() reports a pending
interrupt but the subsequent kvm_apic_has_interrupt() (which invokes
vmx_sync_pir_to_irr() again) returns -1:
WARNING: CPU: 99 PID: 57767 at arch/x86/kvm/vmx/nested.c:4449 vmx_check_nested_events+0x6bf/0x6e0 [kvm_intel]
Call Trace:
kvm_check_and_inject_events
vcpu_enter_guest.constprop.0
vcpu_run
kvm_arch_vcpu_ioctl_run
kvm_vcpu_ioctl
__x64_sys_ioctl
do_syscall_64
entry_SYSCALL_64_after_hwframe
The root cause is a race between vmx_sync_pir_to_irr() on the target vCPU
and __vmx_deliver_posted_interrupt() on a sender vCPU. The sender
performs two individually-atomic operations that are not a single
transaction:
1. pi_test_and_set_pir(vector) -- sets the PIR bit
2. pi_test_and_set_on() -- sets PID.ON
The following interleaving triggers the bug:
Sender vCPU (IPI): Target vCPU (1st sync_pir_to_irr):
B1: set PIR[vector]
A1: pi_clear_on()
A2: pi_harvest_pir() -> sees B1 bit
A3: xchg() -> consumes bit, PIR=0
(1st sync returns correct max_irr)
B2: set PID.ON = 1
Target vCPU (2nd sync_pir_to_irr):
C1: pi_test_on() -> TRUE (from B2)
C2: pi_clear_on() -> ON=0
C3: pi_harvest_pir() -> PIR empty
C4: *max_irr = -1, early return
IRR NOT SCANNED
The interrupt is not lost (it resides in the IRR from the first sync and
is recovered on the next vcpu_enter_guest() iteration), but the incorrect
max_irr causes a spurious WARNING and a wasted L2 VM-Enter/VM-Exit cycle. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Inject #UD for INVLPGA if EFER.SVME=0
INVLPGA should cause a #UD when EFER.SVME is not set. Add a check to
properly inject #UD when EFER.SVME=0.
[sean: tag for stable@] |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION
Drop the WARN in sev_pin_memory() on npages overflowing an int, as the
WARN is comically trivially to trigger from userspace, e.g. by doing:
struct kvm_enc_region range = {
.addr = 0,
.size = -1ul,
};
__vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range);
Note, the checks in sev_mem_enc_register_region() that presumably exist to
verify the incoming address+size are completely worthless, as both "addr"
and "size" are u64s and SEV is 64-bit only, i.e. they _can't_ be greater
than ULONG_MAX. That wart will be cleaned up in the near future.
if (range->addr > ULONG_MAX || range->size > ULONG_MAX)
return -EINVAL;
Opportunistically add a comment to explain why the code calculates the
number of pages the "hard" way, e.g. instead of just shifting @ulen. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: check for nEPT/nNPT in slow flush hypercalls
Checking is_guest_mode(vcpu) is incorrect, because translate_nested_gpa()
is only valid if an L2 guest is running *with nested EPT/NPT enabled*.
Instead use the same condition as translate_nested_gpa() itself. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_cthelper: fix OOB read in nfnl_cthelper_dump_table()
nfnl_cthelper_dump_table() has a 'goto restart' that jumps to a label
inside the for loop body. When the "last" helper saved in cb->args[1]
is deleted between dump rounds, every entry fails the (cur != last)
check, so cb->args[1] is never cleared. The for loop finishes with
cb->args[0] == nf_ct_helper_hsize, and the 'goto restart' jumps back
into the loop body bypassing the bounds check, causing an 8-byte
out-of-bounds read on nf_ct_helper_hash[nf_ct_helper_hsize].
The 'goto restart' block was meant to re-traverse the current bucket
when "last" is no longer found, but it was placed after the for loop
instead of inside it. Move the block into the for loop body so that
the restart only occurs while cb->args[0] is still within bounds.
BUG: KASAN: slab-out-of-bounds in nfnl_cthelper_dump_table+0x9f/0x1b0
Read of size 8 at addr ffff888104ca3000 by task poc_cthelper/131
Call Trace:
nfnl_cthelper_dump_table+0x9f/0x1b0
netlink_dump+0x333/0x880
netlink_recvmsg+0x3e2/0x4b0
sock_recvmsg+0xde/0xf0
__sys_recvfrom+0x150/0x200
__x64_sys_recvfrom+0x76/0x90
do_syscall_64+0xc3/0x6e0
Allocated by task 1:
__kvmalloc_node_noprof+0x21b/0x700
nf_ct_alloc_hashtable+0x65/0xd0
nf_conntrack_helper_init+0x21/0x60
nf_conntrack_init_start+0x18d/0x300
nf_conntrack_standalone_init+0x12/0xc0 |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Eagerly init vgic dist/redist on vgic creation
If vgic_allocate_private_irqs_locked() fails for any odd reason,
we exit kvm_vgic_create() early, leaving dist->rd_regions uninitialised.
kvm_vgic_dist_destroy() then comes along and walks into the weeds
trying to free the RDs. Got to love this stuff.
Solve it by moving all the static initialisation early, and make
sure that if we fail halfway, we're in a reasonable shape to
perform the rest of the teardown. While at it, reset the vgic model
on failure, just in case... |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Remove a user-triggerable WARN on nested_svm_load_cr3() succeeding
Drop the WARN in svm_set_nested_state() on nested_svm_load_cr3() failing
as it is trivially easy to trigger from userspace by modifying CPUID after
loading CR3. E.g. modifying the state restoration selftest like so:
--- tools/testing/selftests/kvm/x86/state_test.c
+++ tools/testing/selftests/kvm/x86/state_test.c
@@ -280,7 +280,16 @@ int main(int argc, char *argv[])
/* Restore state in a new VM. */
vcpu = vm_recreate_with_one_vcpu(vm);
- vcpu_load_state(vcpu, state);
+
+ if (stage == 4) {
+ state->sregs.cr3 = BIT(44);
+ vcpu_load_state(vcpu, state);
+
+ vcpu_set_cpuid_property(vcpu, X86_PROPERTY_MAX_PHY_ADDR, 36);
+ __vcpu_nested_state_set(vcpu, &state->nested);
+ } else {
+ vcpu_load_state(vcpu, state);
+ }
/*
* Restore XSAVE state in a dummy vCPU, first without doing
generates:
WARNING: CPU: 30 PID: 938 at arch/x86/kvm/svm/nested.c:1877 svm_set_nested_state+0x34a/0x360 [kvm_amd]
Modules linked in: kvm_amd kvm irqbypass [last unloaded: kvm]
CPU: 30 UID: 1000 PID: 938 Comm: state_test Tainted: G W 6.18.0-rc7-58e10b63777d-next-vm
Tainted: [W]=WARN
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:svm_set_nested_state+0x34a/0x360 [kvm_amd]
Call Trace:
<TASK>
kvm_arch_vcpu_ioctl+0xf33/0x1700 [kvm]
kvm_vcpu_ioctl+0x4e6/0x8f0 [kvm]
__x64_sys_ioctl+0x8f/0xd0
do_syscall_64+0x61/0xad0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Simply delete the WARN instead of trying to prevent userspace from shoving
"illegal" state into CR3. For better or worse, KVM's ABI allows userspace
to set CPUID after SREGS, and vice versa, and KVM is very permissive when
it comes to guest CPUID. I.e. attempting to enforce the virtual CPU model
when setting CPUID could break userspace. Given that the WARN doesn't
provide any meaningful protection for KVM or benefit for userspace, simply
drop it even though the odds of breaking userspace are minuscule.
Opportunistically delete a spurious newline. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: Skip vcn poison irq release on VF
VF doesn't enable VCN poison irq in VCNv2.5. Skip releasing it and avoid
call trace during deinitialization.
[ 71.913601] [drm] clean up the vf2pf work item
[ 71.915088] ------------[ cut here ]------------
[ 71.915092] WARNING: CPU: 3 PID: 1079 at /tmp/amd.aFkFvSQl/amd/amdgpu/amdgpu_irq.c:641 amdgpu_irq_put+0xc6/0xe0 [amdgpu]
[ 71.915355] Modules linked in: amdgpu(OE-) amddrm_ttm_helper(OE) amdttm(OE) amddrm_buddy(OE) amdxcp(OE) amddrm_exec(OE) amd_sched(OE) amdkcl(OE) drm_suballoc_helper drm_display_helper cec rc_core i2c_algo_bit video wmi binfmt_misc nls_iso8859_1 intel_rapl_msr intel_rapl_common input_leds joydev serio_raw mac_hid qemu_fw_cfg sch_fq_codel dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua efi_pstore ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 hid_generic crct10dif_pclmul crc32_pclmul polyval_clmulni polyval_generic ghash_clmulni_intel usbhid 8139too sha256_ssse3 sha1_ssse3 hid psmouse bochs i2c_i801 ahci drm_vram_helper libahci i2c_smbus lpc_ich drm_ttm_helper 8139cp mii ttm aesni_intel crypto_simd cryptd
[ 71.915484] CPU: 3 PID: 1079 Comm: rmmod Tainted: G OE 6.8.0-87-generic #88~22.04.1-Ubuntu
[ 71.915489] Hardware name: Red Hat KVM/RHEL, BIOS 1.16.3-2.el9_5.1 04/01/2014
[ 71.915492] RIP: 0010:amdgpu_irq_put+0xc6/0xe0 [amdgpu]
[ 71.915768] Code: 75 84 b8 ea ff ff ff eb d4 44 89 ea 48 89 de 4c 89 e7 e8 fd fc ff ff 5b 41 5c 41 5d 41 5e 5d 31 d2 31 f6 31 ff e9 55 30 3b c7 <0f> 0b eb d4 b8 fe ff ff ff eb a8 e9 b7 3b 8a 00 66 2e 0f 1f 84 00
[ 71.915771] RSP: 0018:ffffcf0800eafa30 EFLAGS: 00010246
[ 71.915775] RAX: 0000000000000000 RBX: ffff891bda4b0668 RCX: 0000000000000000
[ 71.915777] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 71.915779] RBP: ffffcf0800eafa50 R08: 0000000000000000 R09: 0000000000000000
[ 71.915781] R10: 0000000000000000 R11: 0000000000000000 R12: ffff891bda480000
[ 71.915782] R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
[ 71.915792] FS: 000070cff87c4c40(0000) GS:ffff893abfb80000(0000) knlGS:0000000000000000
[ 71.915795] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 71.915797] CR2: 00005fa13073e478 CR3: 000000010d634006 CR4: 0000000000770ef0
[ 71.915800] PKRU: 55555554
[ 71.915802] Call Trace:
[ 71.915805] <TASK>
[ 71.915809] vcn_v2_5_hw_fini+0x19e/0x1e0 [amdgpu] |
