Commit d1e388db authored by Oliver Upton's avatar Oliver Upton Committed by Jinjie Ruan
Browse files

KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache 

stable inclusion
from stable-v5.10.209
commit ba7be666740847d967822bed15500656b26bc703
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I93EEI
CVE: CVE-2024-26598

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ba7be666740847d967822bed15500656b26bc703



--------------------------------

There is a potential UAF scenario in the case of an LPI translation
cache hit racing with an operation that invalidates the cache, such
as a DISCARD ITS command. The root of the problem is that
vgic_its_check_cache() does not elevate the refcount on the vgic_irq
before dropping the lock that serializes refcount changes.

Have vgic_its_check_cache() raise the refcount on the returned vgic_irq
and add the corresponding decrement after queueing the interrupt.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240104183233.3560639-1-oliver.upton@linux.dev
parent a5194e63

arch/arm64/kvm/vgic/vgic-its.c

+5 −0
Original line number Diff line number Diff line
@@ -601,7 +601,11 @@ static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db, 
	cacheid = cpu % LPI_TRANS_CACHES_NUM;



	raw_spin_lock_irqsave(&dist->lpi_translation_cache[cacheid].lpi_cache_lock, flags);



	irq = __vgic_its_check_cache(dist, db, devid, eventid, cacheid);

	if (irq)

		vgic_get_irq_kref(irq);



	raw_spin_unlock_irqrestore(&dist->lpi_translation_cache[cacheid].lpi_cache_lock, flags);



	return irq;
@@ -778,6 +782,7 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, 
	raw_spin_lock_irqsave(&irq->irq_lock, flags);

	irq->pending_latch = true;

	vgic_queue_irq_unlock(kvm, irq, flags);

	vgic_put_irq(kvm, irq);



	return 0;

}