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: Eric Auger <[email protected]> Signed-off-by: Alex Williamson <[email protected]> --- drivers/vfio/pci/vfio_pci_intrs.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 3b3ba15..e9ea3fe 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -309,14 +309,14 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, int vector, int fd, bool msix) { 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; - int ret; + int irq, ret; - if (vector >= vdev->num_ctx) + if (vector < 0 || vector >= vdev->num_ctx) return -EINVAL; + irq = msix ? vdev->msix[vector].vector : pdev->irq + vector; + if (vdev->ctx[vector].trigger) { free_irq(irq, vdev->ctx[vector].trigger); 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) return 0; - vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "%s[%d](%s)", - name, vector, pci_name(pdev)); + vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "vfio-msi%s[%d](%s)", + msix ? "x" : "", vector, + pci_name(pdev)); if (!vdev->ctx[vector].name) return -ENOMEM; @@ -379,7 +380,7 @@ static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start, { int i, j, ret = 0; - if (start + count > vdev->num_ctx) + if (start >= vdev->num_ctx || start + count > vdev->num_ctx) return -EINVAL; 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) { - for (--j; j >= start; j--) + for (--j; j >= (int)start; j--) vfio_msi_set_vector_signal(vdev, j, -1, msix); }
