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

[Andrew Scull]

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 at 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