From d3553a52490dcac54f45083f8fa018e26c22e947 Mon Sep 17 00:00:00 2001
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Date: Thu, 27 May 2010 19:01:58 +0900
Subject: [PATCH] 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>
---
drivers/vhost/net.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index aa88911c9504..0f41c9195e9b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -593,17 +593,17 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
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);
--
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