virtio: pci: Check virtio capability is in bounds

Ensure the virtio PCI capabilities are contained within the bounds of
the device's configuration space. The expected size of the capability is
passed when searching for the capability to enforce this check.

Signed-off-by: Andrew Scull <ascull@google.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Andrew Scull 2022-04-21 16:11:04 +00:00 committed by Tom Rini
parent f2c1ef1b6d
commit 6a8cb878a2

View file

@ -397,18 +397,27 @@ static int virtio_pci_notify(struct udevice *udev, struct virtqueue *vq)
*
* @udev: the transport device
* @cfg_type: the VIRTIO_PCI_CAP_* value we seek
* @cap_size: expected size of the capability
*
* Return: offset of the configuration structure
*/
static int virtio_pci_find_capability(struct udevice *udev, u8 cfg_type)
static int virtio_pci_find_capability(struct udevice *udev, u8 cfg_type,
size_t cap_size)
{
int pos;
int offset;
u8 type, bar;
assert(cap_size >= sizeof(struct virtio_pci_cap));
assert(cap_size <= PCI_CFG_SPACE_SIZE);
for (pos = dm_pci_find_capability(udev, PCI_CAP_ID_VNDR);
pos > 0;
pos = dm_pci_find_next_capability(udev, pos, PCI_CAP_ID_VNDR)) {
/* Ensure the capability is within bounds */
if (PCI_CFG_SPACE_SIZE - cap_size < pos)
return 0;
offset = pos + offsetof(struct virtio_pci_cap, cfg_type);
dm_pci_read_config8(udev, offset, &type);
offset = pos + offsetof(struct virtio_pci_cap, bar);
@ -496,7 +505,8 @@ static int virtio_pci_probe(struct udevice *udev)
uc_priv->vendor = subvendor;
/* Check for a common config: if not, use legacy mode (bar 0) */
common = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_COMMON_CFG);
common = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_COMMON_CFG,
sizeof(struct virtio_pci_cap));
if (!common) {
printf("(%s): leaving for legacy driver\n", udev->name);
return -ENODEV;
@ -510,7 +520,8 @@ static int virtio_pci_probe(struct udevice *udev)
}
/* If common is there, notify should be too */
notify = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_NOTIFY_CFG);
notify = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_NOTIFY_CFG,
sizeof(struct virtio_pci_notify_cap));
if (!notify) {
printf("(%s): missing capabilities %i/%i\n", udev->name,
common, notify);
@ -524,7 +535,8 @@ static int virtio_pci_probe(struct udevice *udev)
* Device capability is only mandatory for devices that have
* device-specific configuration.
*/
device = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_DEVICE_CFG);
device = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_DEVICE_CFG,
sizeof(struct virtio_pci_cap));
if (device) {
offset = device + offsetof(struct virtio_pci_cap, length);
dm_pci_read_config32(udev, offset, &priv->device_len);