[PATCH 3.16 055/133] staging: lustre: obdclass: return -EFAULT if copy_from_user() fails

[Ben Hutchings]

3.16.51-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit 092c3def24bb68a00ff58c76ed67b9ff448387ce upstream.

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@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/staging/lustre/lustre/obdclass/class_obd.c
+++ b/drivers/staging/lustre/lustre/obdclass/class_obd.c
@@ -232,8 +232,8 @@ int class_handle_ioctl(unsigned int cmd,
 		OBD_ALLOC(lcfg, data->ioc_plen1);
 		if (lcfg == NULL)
 			GOTO(out, err = -ENOMEM);
-		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)