nfsd: properly handle embedded newlines in fault_injection input

Currently rpc_pton() fails to handle the case where you echo an address
into the file, as it barfs on the newline. Ensure that we NULL out the
first occurrence of any newline.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/fault_inject.c

@@ -115,11 +115,19 @@ static ssize_t fault_inject_write(struct file *file, const char __user *buf,
 	struct net *net = current->nsproxy->net_ns;
 	struct sockaddr_storage sa;
 	u64 val;
+	char *nl;
 
 	if (copy_from_user(write_buf, buf, size))
 		return -EFAULT;
 	write_buf[size] = '\0';
 
+	/* Deal with any embedded newlines in the string */
+	nl = strchr(write_buf, '\n');
+	if (nl) {
+		size = nl - write_buf;
+		*nl = '\0';
+	}
+
 	size = rpc_pton(net, write_buf, size, (struct sockaddr *)&sa, sizeof(sa));
 	if (size > 0)
 		nfsd_inject_set_client(file_inode(file)->i_private, &sa, size);