[PATCH v3 03/18] virtio: pci: Bounds check device config access

[Andrew Scull]

The device config is optional, so check it was present and mapped before
trying to use the pointer. Bounds violations are an error, not just a
warning, so bail if the checks fail.

Signed-off-by: Andrew Scull <ascull at google.com>
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
---
 drivers/virtio/virtio_pci_modern.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 55d25cb81b..bcf9f18997 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -114,7 +114,11 @@ static int virtio_pci_get_config(struct udevice *udev, unsigned int offset,
 	__le16 w;
 	__le32 l;
 
-	WARN_ON(offset + len > priv->device_len);
+	if (!priv->device)
+		return -ENOSYS;
+
+	if (offset + len > priv->device_len)
+		return -EINVAL;
 
 	switch (len) {
 	case 1:
@@ -136,7 +140,7 @@ static int virtio_pci_get_config(struct udevice *udev, unsigned int offset,
 		memcpy(buf + sizeof(l), &l, sizeof(l));
 		break;
 	default:
-		WARN_ON(true);
+		return -EINVAL;
 	}
 
 	return 0;
@@ -150,7 +154,11 @@ static int virtio_pci_set_config(struct udevice *udev, unsigned int offset,
 	__le16 w;
 	__le32 l;
 
-	WARN_ON(offset + len > priv->device_len);
+	if (!priv->device)
+		return -ENOSYS;
+
+	if (offset + len > priv->device_len)
+		return -EINVAL;
 
 	switch (len) {
 	case 1:
@@ -172,7 +180,7 @@ static int virtio_pci_set_config(struct udevice *udev, unsigned int offset,
 		iowrite32(le32_to_cpu(l), priv->device + offset + sizeof(l));
 		break;
 	default:
-		WARN_ON(true);
+		return -EINVAL;
 	}
 
 	return 0;
-- 
2.36.0.rc2.479.g8af0fa9b8e-goog