The copy_to_user() function returns the number of bytes remaining to be copied. In this code, that positive return is checked at the end of the function and we return zero/success. What we should do instead is return -EFAULT. Fixes: a7b4f989a629 ("netfilter: ipset: IP set core support") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> --- net/netfilter/ipset/ip_set_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index e64d5f9a89dd..15b8d4318207 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -2129,7 +2129,8 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len) } /* end of switch(op) */ copy: - ret = copy_to_user(user, data, copylen); + if (copy_to_user(user, data, copylen)) + ret = -EFAULT; done: vfree(data); -- 2.20.1