linux-kernel - [PATCH 1/2] vfio/fsl-mc: return -EFAULT if copy_to

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Date:   Fri, 23 Oct 2020 14:34:50 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Diana Craciun <diana.craciun@....nxp.com>
Cc:     Alex Williamson <alex.williamson@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Bharat Bhushan <Bharat.Bhushan@....com>,
        Eric Auger <eric.auger@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH 1/2] vfio/fsl-mc: return -EFAULT if copy_to_user() fails

The copy_to_user() function returns the number of bytes remaining to be
copied, but this code should return -EFAULT.

Fixes: df747bcd5b21 ("vfio/fsl-mc: Implement VFIO_DEVICE_GET_REGION_INFO ioctl call")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 drivers/vfio/fsl-mc/vfio_fsl_mc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
index 0113a980f974..21f22e3da11f 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
@@ -248,7 +248,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 		info.size = vdev->regions[info.index].size;
 		info.flags = vdev->regions[info.index].flags;
 
-		return copy_to_user((void __user *)arg, &info, minsz);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
+		return 0;
 	}
 	case VFIO_DEVICE_GET_IRQ_INFO:
 	{
@@ -267,7 +269,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 		info.flags = VFIO_IRQ_INFO_EVENTFD;
 		info.count = 1;
 
-		return copy_to_user((void __user *)arg, &info, minsz);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
+		return 0;
 	}
 	case VFIO_DEVICE_SET_IRQS:
 	{
-- 
2.28.0