Add a safety check to ensure that the length of data written by the
device is at least as large as the status length. If this condition is
not met, it indicates a potential error in the device's response.
This change aligns with the virtio specification, which states:
"The driver MUST NOT make assumptions about data in device-writable
buffers beyond the first len bytes, and SHOULD ignore this data."
By failing the admin command when len is insufficient, we ensure
that the driver does not process potentially invalid or incomplete
status from the device.
Signed-off-by: Israel Rukshin <isra...@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurto...@nvidia.com>
---
drivers/virtio/virtio_pci_modern.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
index 7209390a5cbf..0374e86aece3 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -48,6 +48,7 @@ void vp_modern_avq_done(struct virtqueue *vq)
{
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
struct virtio_pci_admin_vq *admin_vq = &vp_dev->admin_vq;
+ unsigned int status_size = sizeof(struct virtio_admin_cmd_status);
struct virtio_admin_cmd *cmd;
unsigned long flags;
unsigned int len;
@@ -56,8 +57,10 @@ void vp_modern_avq_done(struct virtqueue *vq)
do {
virtqueue_disable_cb(vq);
while ((cmd = virtqueue_get_buf(vq, &len))) {
- cmd->result_sg_size =
- len - sizeof(struct virtio_admin_cmd_status);
+ if (len < status_size)
+ cmd->ret = -EIO;
+ else
+ cmd->result_sg_size = len - status_size;
complete(&cmd->completion);
}
} while (!virtqueue_enable_cb(vq));
--
2.34.1
