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KVM: s390: pci: fix GAIT table indexing due to double-scaling pointer arithmetic

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kvm_s390_pci_aif_enable(), kvm_s390_pci_aif_disable(), and
aen_host_forward() index the GAIT by manually multiplying the index
with sizeof(struct zpci_gaite).

Since aift->gait is already a struct zpci_gaite pointer, this
double-scales the offset, accessing element aisb*16 instead of aisb.

This causes out-of-bounds accesses when aisb >= 32 (with
ZPCI_NR_DEVICES=512)

Fix by removing the erroneous sizeof multiplication.

Fixes: 3c5a1b6f0a ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding")
Fixes: 73f91b0043 ("KVM: s390: pci: enable host forwarding of Adapter Event Notifications")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
This commit is contained in:
Junrui Luo
2026-04-15 17:26:55 +08:00
committed by Christian Borntraeger
parent 028ef9c96e
commit 16d990a154
2 changed files with 3 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
arch/s390/kvm/interrupt.c
View File

@@ -3307,8 +3307,7 @@ static void aen_host_forward(unsigned long si)
struct zpci_gaite *gaite;
struct kvm *kvm;
gaite = (struct zpci_gaite *)aift->gait +
(si * sizeof(struct zpci_gaite));
gaite = aift->gait + si;
if (gaite->count == 0)
return;
if (gaite->aisb != 0)

6
arch/s390/kvm/pci.c
View File

@@ -290,8 +290,7 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
phys_to_virt(fib->fmt0.aibv));
spin_lock_irq(&aift->gait_lock);
gaite = (struct zpci_gaite *)aift->gait + (zdev->aisb *
sizeof(struct zpci_gaite));
gaite = aift->gait + zdev->aisb;
/* If assist not requested, host will get all alerts */
if (assist)
@@ -357,8 +356,7 @@ static int kvm_s390_pci_aif_disable(struct zpci_dev *zdev, bool force)
if (zdev->kzdev->fib.fmt0.aibv == 0)
goto out;
spin_lock_irq(&aift->gait_lock);
gaite = (struct zpci_gaite *)aift->gait + (zdev->aisb *
sizeof(struct zpci_gaite));
gaite = aift->gait + zdev->aisb;
isc = gaite->gisc;
gaite->count--;
if (gaite->count == 0) {