vhost-net: fix to check the return value of copy_to/from_user() correctly
copy_to/from_user() returns the number of bytes that could not be copied.
So we need to check if it is not zero, and in that case, we should return
the error number -EFAULT rather than directly return the return value from
copy_to/from_user().
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index aa88911c..0f41c91 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -593,17 +593,17 @@
int r;
switch (ioctl) {
case VHOST_NET_SET_BACKEND:
- r = copy_from_user(&backend, argp, sizeof backend);
- if (r < 0)
- return r;
+ if (copy_from_user(&backend, argp, sizeof backend))
+ return -EFAULT;
return vhost_net_set_backend(n, backend.index, backend.fd);
case VHOST_GET_FEATURES:
features = VHOST_FEATURES;
- return copy_to_user(featurep, &features, sizeof features);
+ if (copy_to_user(featurep, &features, sizeof features))
+ return -EFAULT;
+ return 0;
case VHOST_SET_FEATURES:
- r = copy_from_user(&features, featurep, sizeof features);
- if (r < 0)
- return r;
+ if (copy_from_user(&features, featurep, sizeof features))
+ return -EFAULT;
if (features & ~VHOST_FEATURES)
return -EOPNOTSUPP;
return vhost_net_set_features(n, features);
