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vfio/pci: Fix integer overflows, bitmask check

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The VFIO_DEVICE_SET_IRQS ioctl did not sufficiently sanitize
user-supplied integers, potentially allowing memory corruption. This
patch adds appropriate integer overflow checks, checks the range bounds
for VFIO_IRQ_SET_DATA_NONE, and also verifies that only single element
in the VFIO_IRQ_SET_DATA_TYPE_MASK bitmask is set.
VFIO_IRQ_SET_ACTION_TYPE_MASK is already correctly checked later in
vfio_pci_set_irqs_ioctl().

Furthermore, a kzalloc is changed to a kcalloc because the use of a
kzalloc with an integer multiplication allowed an integer overflow
condition to be reached without this patch. kcalloc checks for overflow
and should prevent a similar occurrence.

Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Vlad Tsyrklevich 2016-10-12 18:51:24 +02:00 committed by Alex Williamson
parent 07d9a38068
commit 05692d7005
2 changed files with 22 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/vfio/pci/vfio_pci.c
View File

@ -829,8 +829,9 @@ static long vfio_pci_ioctl(void *device_data,
} else if (cmd == VFIO_DEVICE_SET_IRQS) {
struct vfio_irq_set hdr;
size_t size;
u8 *data = NULL;
int ret = 0;
int max, ret = 0;
minsz = offsetofend(struct vfio_irq_set, count);
@ -838,23 +839,31 @@ static long vfio_pci_ioctl(void *device_data,
return -EFAULT;
if (hdr.argsz < minsz || hdr.index >= VFIO_PCI_NUM_IRQS ||
hdr.count >= (U32_MAX - hdr.start) ||
hdr.flags & ~(VFIO_IRQ_SET_DATA_TYPE_MASK |
VFIO_IRQ_SET_ACTION_TYPE_MASK))
return -EINVAL;
if (!(hdr.flags & VFIO_IRQ_SET_DATA_NONE)) {
size_t size;
int max = vfio_pci_get_irq_count(vdev, hdr.index);
max = vfio_pci_get_irq_count(vdev, hdr.index);
if (hdr.start >= max || hdr.start + hdr.count > max)
return -EINVAL;
if (hdr.flags & VFIO_IRQ_SET_DATA_BOOL)
size = sizeof(uint8_t);
else if (hdr.flags & VFIO_IRQ_SET_DATA_EVENTFD)
size = sizeof(int32_t);
else
return -EINVAL;
switch (hdr.flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
case VFIO_IRQ_SET_DATA_NONE:
size = 0;
break;
case VFIO_IRQ_SET_DATA_BOOL:
size = sizeof(uint8_t);
break;
case VFIO_IRQ_SET_DATA_EVENTFD:
size = sizeof(int32_t);
break;
default:
return -EINVAL;
}
if (hdr.argsz - minsz < hdr.count * size ||
hdr.start >= max || hdr.start + hdr.count > max)
if (size) {
if (hdr.argsz - minsz < hdr.count * size)
return -EINVAL;
data = memdup_user((void __user *)(arg + minsz),

2
drivers/vfio/pci/vfio_pci_intrs.c
View File

@ -256,7 +256,7 @@ static int vfio_msi_enable(struct vfio_pci_device *vdev, int nvec, bool msix)
if (!is_irq_none(vdev))
return -EINVAL;
vdev->ctx = kzalloc(nvec * sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
vdev->ctx = kcalloc(nvec, sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
if (!vdev->ctx)
return -ENOMEM;