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| author | Prasanna Kumar T S M <ptsm@linux.microsoft.com> | 2026-04-17 23:27:56 +0300 |
|---|---|---|
| committer | Alex Williamson <alex@shazbot.org> | 2026-04-21 21:01:22 +0300 |
| commit | 5ea5880764cbb164afb17a62e76ca75dc371409d (patch) | |
| tree | 155d52925dd56b19ca69b15bae3c46c2dedcc52b | |
| parent | 64965b8a4274b82330433fe8888d999506a81a94 (diff) | |
| download | linux-5ea5880764cbb164afb17a62e76ca75dc371409d.tar.xz | |
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 <ptsm@linux.microsoft.com>
Acked-by: Nipun Gupta <nipun.gupta@amd.com>
Signed-off-by: Alex Williamson <alex.williamson@nvidia.com>
Acked-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Link: https://lore.kernel.org/r/20260417202800.88287-2-alex.williamson@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
| -rw-r--r-- | drivers/vfio/cdx/intr.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/vfio/cdx/intr.c b/drivers/vfio/cdx/intr.c index 8f4402cec9c5..c0eed065e8ef 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; |