This is a note to let you know that I've just added the patch titled
KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-arm64-vgic-its-avoid-potential-uaf-in-lpi-translation-cache.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ad362fe07fecf0aba839ff2cc59a3617bd42c33f Mon Sep 17 00:00:00 2001
From: Oliver Upton <oliver.upton@xxxxxxxxx>
Date: Thu, 4 Jan 2024 18:32:32 +0000
Subject: KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
From: Oliver Upton <oliver.upton@xxxxxxxxx>
commit ad362fe07fecf0aba839ff2cc59a3617bd42c33f upstream.
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@xxxxxxxxxxxxxxx
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240104183233.3560639-1-oliver.upton@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/vgic/vgic-its.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -584,7 +584,11 @@ static struct vgic_irq *vgic_its_check_c
unsigned long flags;
raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
+
irq = __vgic_its_check_cache(dist, db, devid, eventid);
+ if (irq)
+ vgic_get_irq_kref(irq);
+
raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
return irq;
@@ -763,6 +767,7 @@ int vgic_its_inject_cached_translation(s
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;
}
Patches currently in stable-queue which might be from oliver.upton@xxxxxxxxx are
queue-6.6/kvm-arm64-vgic-its-avoid-potential-uaf-in-lpi-translation-cache.patch
