[PATCH 07/11] virtio: pci: Check virtio configs are mapped

Andrew Scull
2022-03-20T11:44:38Z

The calls to `virtio_pci_map_capability()` return NULL on error. If this
happens, later accesses to the pointers would be unsafe. Avoid this by
failing if the configs were not successfully mapped.

Signed-off-by: Andrew Scull <ascull@google.com>
---
drivers/virtio/virtio_pci_modern.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 38a0da0a84..2f1a1cedbc 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -534,7 +534,19 @@ static int virtio_pci_probe(struct udevice *udev)
return -EINVAL;
}

+ /* Map configuration structures */
+ priv->common = virtio_pci_map_capability(udev, &common_cap);
+ if (!priv->common) {
+ printf("(%s): could not map common config\n", udev->name);
+ return -EINVAL;
+ }
+
priv->notify_len = notify_cap.length;
+ priv->notify_base = virtio_pci_map_capability(udev, &notify_cap);
+ if (!priv->notify_base) {
+ printf("(%s): could not map notify config\n", udev->name);
+ return -EINVAL;
+ }

/*
* Device capability is only mandatory for devices that have
@@ -543,13 +555,16 @@ static int virtio_pci_probe(struct udevice *udev)
device = virtio_pci_find_capability(udev, VIRTIO_PCI_CAP_DEVICE_CFG,
sizeof(struct virtio_pci_cap),
&device_cap);
- if (device)
+ if (device) {
priv->device_len = device_cap.length;
+ priv->device = virtio_pci_map_capability(udev, &device_cap);
+ if (!priv->device) {
+ printf("(%s): could not map device config\n",
+ udev->name);
+ return -EINVAL;
+ }
+ }

- /* Map configuration structures */
- priv->common = virtio_pci_map_capability(udev, &common_cap);
- priv->notify_base = virtio_pci_map_capability(udev, &notify_cap);
- priv->device = virtio_pci_map_capability(udev, &device_cap);
debug("(%p): common @ %p, notify base @ %p, device @ %p\n",
udev, priv->common, priv->notify_base, priv->device);

--
2.35.1.894.gb6a874cedc-goog