[UNIKRAFT PATCH 2/2] plat/virtio: Add error check for tag name

[Sharan Santhanam <sharan.santhanam@xxxxxxxxx>]

During virtio-9p configuration get we check for error while getting
the tag length but not the tag. The patch adds this check

Signed-off-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
---
 plat/drivers/virtio/virtio_9p.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/plat/drivers/virtio/virtio_9p.c b/plat/drivers/virtio/virtio_9p.c
index 7bd99b8d..a783eba2 100644
--- a/plat/drivers/virtio/virtio_9p.c
+++ b/plat/drivers/virtio/virtio_9p.c
@@ -359,14 +359,23 @@ static int virtio_9p_feature_negotiate(struct 
virtio_9p_device *d)
                goto out;
        }
 
-       virtio_config_get(d->vdev,
+
+       if (virtio_config_get(d->vdev,
                          __offsetof(struct virtio_9p_config, tag),
-                         d->tag, tag_len, 1);
+                         d->tag, tag_len, 1) < 0) {
+               uk_pr_err(DRIVER_NAME": Failed to read the tag on the device 
%p\n",
+                         d);
+               rc = -EAGAIN;
+               goto free_mem;
+       }
        d->tag[tag_len] = '\0';
 
        d->vdev->features &= host_features;
        virtio_feature_set(d->vdev, d->vdev->features);
+       return 0;
 
+free_mem:
+       uk_free(a, d->tag);
 out:
        return rc;
 }
-- 
2.20.1