From: Oliver Upton oliver.upton@linux.dev

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=...

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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: Oliver Upton oliver.upton@linux.dev Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20240104183233.3560639-1-oliver.upton@linux.dev --- arch/arm64/kvm/vgic/vgic-its.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index ee3b9df60a59..9c7bd5a8aa35 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -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; }