From 092c3def24bb68a00ff58c76ed67b9ff448387ce Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Sat, 26 Aug 2017 09:04:18 +0300
Subject: [PATCH] staging: lustre: obdclass: return -EFAULT if copy_from_user() fails
Git-commit: 092c3def24bb68a00ff58c76ed67b9ff448387ce
Patch-mainline: v4.14-rc1
References: bsc#1051510

The copy_from_user() function returns the number of bytes which we
weren't able to copy.  We don't want to return that to the user but
instead we want to return -EFAULT.

Fixes: d7e09d0397e8 ("staging: add Lustre file system client support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/lustre/lustre/obdclass/class_obd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/lustre/lustre/obdclass/class_obd.c b/drivers/staging/lustre/lustre/obdclass/class_obd.c
index 8ad3adb2ceb1..545358923271 100644
--- a/drivers/staging/lustre/lustre/obdclass/class_obd.c
+++ b/drivers/staging/lustre/lustre/obdclass/class_obd.c
@@ -180,7 +180,8 @@ int class_handle_ioctl(unsigned int cmd, unsigned long arg)
 			err = -ENOMEM;
 			goto out;
 		}
-		err = copy_from_user(lcfg, data->ioc_pbuf1, data->ioc_plen1);
+		if (copy_from_user(lcfg, data->ioc_pbuf1, data->ioc_plen1))
+			err = -EFAULT;
 		if (!err)
 			err = lustre_cfg_sanity_check(lcfg, data->ioc_plen1);
 		if (!err)
-- 
2.18.0