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From:   Wang Qing <wangqing@vivo.com>
To:     Cornelia Huck <cohuck@redhat.com>,
        Eric Farman <farman@linux.ibm.com>,
        Halil Pasic <pasic@linux.ibm.com>,
        Vineeth Vijayan <vneethv@linux.ibm.com>,
        Peter Oberparleiter <oberpar@linux.ibm.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        linux-s390@vger.kernel.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Wang Qing <wangqing@vivo.com>
Subject: [PATCH] s390: cio: Return -EFAULT if copy_to_user() fails
Date:   Mon,  1 Mar 2021 20:01:33 +0800
Message-Id: <1614600093-13992-1-git-send-email-wangqing@vivo.com>
Precedence: bulk

The copy_to_user() function returns the number of bytes remaining to be
copied, but we want to return -EFAULT if the copy doesn't complete.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 drivers/s390/cio/vfio_ccw_ops.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 68106be..557d0b8
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -543,7 +543,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 		if (ret)
 			return ret;
 
-		return copy_to_user((void __user *)arg, &info, minsz);
+		return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
 	}
 	case VFIO_DEVICE_GET_REGION_INFO:
 	{
@@ -561,7 +561,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 		if (ret)
 			return ret;
 
-		return copy_to_user((void __user *)arg, &info, minsz);
+		return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
 	}
 	case VFIO_DEVICE_GET_IRQ_INFO:
 	{
-- 
2.7.4