From: Prasanna Kumar T S M Date: Fri, 17 Apr 2026 20:27:56 +0000 (-0600) Subject: vfio/cdx: Fix NULL pointer dereference in interrupt trigger path X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5ea5880764cbb164afb17a62e76ca75dc371409d;p=thirdparty%2Fkernel%2Fstable.git vfio/cdx: Fix NULL pointer dereference in interrupt trigger path Add validation to ensure MSI is configured before accessing cdx_irqs array in vfio_cdx_set_msi_trigger(). Without this check, userspace can trigger a NULL pointer dereference by calling VFIO_DEVICE_SET_IRQS with VFIO_IRQ_SET_DATA_BOOL or VFIO_IRQ_SET_DATA_NONE flags before ever setting up interrupts via VFIO_IRQ_SET_DATA_EVENTFD. The vfio_cdx_msi_enable() function allocates the cdx_irqs array and sets config_msi to 1 only when called through the EVENTFD path. The trigger loop (for DATA_BOOL/DATA_NONE) assumed this had already been done, but there was no enforcement of this call ordering. This matches the protection used in the PCI VFIO driver where vfio_pci_set_msi_trigger() checks irq_is() before the trigger loop. Fixes: 848e447e000c ("vfio/cdx: add interrupt support") Cc: stable@vger.kernel.org Signed-off-by: Prasanna Kumar T S M Acked-by: Nipun Gupta Signed-off-by: Alex Williamson Acked-by: Nikhil Agarwal Link: https://lore.kernel.org/r/20260417202800.88287-2-alex.williamson@nvidia.com Signed-off-by: Alex Williamson --- diff --git a/drivers/vfio/cdx/intr.c b/drivers/vfio/cdx/intr.c index 8f4402cec9c50..c0eed065e8ef7 100644 --- a/drivers/vfio/cdx/intr.c +++ b/drivers/vfio/cdx/intr.c @@ -175,6 +175,10 @@ static int vfio_cdx_set_msi_trigger(struct vfio_cdx_device *vdev, return ret; } + /* Ensure MSI is configured before accessing cdx_irqs */ + if (!vdev->config_msi) + return -EINVAL; + for (i = start; i < start + count; i++) { if (!vdev->cdx_irqs[i].trigger) continue;