drm/radeon/kms: add missing copy from user

This hasn't mattered up until the ioctl started using the value, and it fell
apart.

fixes fd.o 29340, Ubuntu LP 606081

[airlied: cleaned up whitespace and don't need an error before pushing]

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index ddcd3b13f151..948a2f454e42 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -112,7 +112,9 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 
         info = data;
         value_ptr = (uint32_t *)((unsigned long)info->value);
-        value = *value_ptr;
+        if (DRM_COPY_FROM_USER(&value, value_ptr, sizeof(value)))
+                return -EFAULT;
+
         switch (info->request) {
         case RADEON_INFO_DEVICE_ID:
                 value = dev->pci_device;