Commit b95d9305 authored by Alex Williamson's avatar Alex Williamson
Browse files

vfio/pci: Fix unsigned comparison overflow 



Signed versus unsigned comparisons are implicitly cast to unsigned,
which result in a couple possible overflows.  For instance (start +
count) might overflow and wrap, getting through our validation test.
Also when unwinding setup, -1 being compared as unsigned doesn't
produce the intended stop condition.  Fix both of these and also fix
vfio_msi_set_vector_signal() to validate parameters before using the
vector index, though none of the callers should pass bad indexes
anymore.

Reported-by: default avatarEric Auger <eric.auger@linaro.org>
Reviewed-by: default avatarEric Auger <eric.auger@linaro.org>
Tested-by: default avatarEric Auger <eric.auger@linaro.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 81f70ba2

drivers/vfio/pci/vfio_pci_intrs.c

+9 −8
Original line number Original line Diff line number Diff line
@@ -309,14 +309,14 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, 
				      int vector, int fd, bool msix)

				      int vector, int fd, bool msix)

{

{

	struct pci_dev *pdev = vdev->pdev;

	struct pci_dev *pdev = vdev->pdev;

	int irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;

	char *name = msix ? "vfio-msix" : "vfio-msi";

	struct eventfd_ctx *trigger;

	struct eventfd_ctx *trigger;

	int ret;

	int irq, ret;





	if (vector >= vdev->num_ctx)

	if (vector < 0 || vector >= vdev->num_ctx)

		return -EINVAL;

		return -EINVAL;





	irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;



	if (vdev->ctx[vector].trigger) {

	if (vdev->ctx[vector].trigger) {

		free_irq(irq, vdev->ctx[vector].trigger);

		free_irq(irq, vdev->ctx[vector].trigger);

		irq_bypass_unregister_producer(&vdev->ctx[vector].producer);

		irq_bypass_unregister_producer(&vdev->ctx[vector].producer);
@@ -328,8 +328,9 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, 
	if (fd < 0)

	if (fd < 0)

		return 0;

		return 0;





	vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "%s[%d](%s)",

	vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "vfio-msi%s[%d](%s)",

					   name, vector, pci_name(pdev));

					   msix ? "x" : "", vector,

					   pci_name(pdev));

	if (!vdev->ctx[vector].name)

	if (!vdev->ctx[vector].name)

		return -ENOMEM;

		return -ENOMEM;
@@ -379,7 +380,7 @@ static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start, 
{

{

	int i, j, ret = 0;

	int i, j, ret = 0;





	if (start + count > vdev->num_ctx)

	if (start >= vdev->num_ctx || start + count > vdev->num_ctx)

		return -EINVAL;

		return -EINVAL;





	for (i = 0, j = start; i < count && !ret; i++, j++) {

	for (i = 0, j = start; i < count && !ret; i++, j++) {
@@ -388,7 +389,7 @@ static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start, 
	}

	}





	if (ret) {

	if (ret) {

		for (--j; j >= start; j--)

		for (--j; j >= (int)start; j--)

			vfio_msi_set_vector_signal(vdev, j, -1, msix);

			vfio_msi_set_vector_signal(vdev, j, -1, msix);

	}

	}