[PATCH 186/190] Revert "virt: vbox: Only copy_from_user the request-header once"

[Greg Kroah-Hartman]

This reverts commit bd23a7269834dc7c1f93e83535d16ebc44b75eba.

Commits from @umn.edu addresses have been found to be submitted in "bad
faith" to try to test the kernel community's ability to review "known
malicious" changes.  The result of these submissions can be found in a
paper published at the 42nd IEEE Symposium on Security and Privacy
entitled, "Open Source Insecurity: Stealthily Introducing
Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
of Minnesota) and Kangjie Lu (University of Minnesota).

Because of this, all submissions from this group must be reverted from
the kernel tree and will need to be re-reviewed again to determine if
they actually are a valid fix.  Until that work is complete, remove this
change to ensure that no problems are being introduced into the
codebase.

Cc: Wenwen Wang <wang6495@xxxxxxx>
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/virt/vboxguest/vboxguest_linux.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/virt/vboxguest/vboxguest_linux.c b/drivers/virt/vboxguest/vboxguest_linux.c
index 73eb34849eab..f5cd9cfa1ef6 100644
--- a/drivers/virt/vboxguest/vboxguest_linux.c
+++ b/drivers/virt/vboxguest/vboxguest_linux.c
@@ -142,9 +142,7 @@ static long vbg_misc_device_ioctl(struct file *filp, unsigned int req,
 	if (!buf)
 		return -ENOMEM;
 
-	*((struct vbg_ioctl_hdr *)buf) = hdr;
-	if (copy_from_user(buf + sizeof(hdr), (void *)arg + sizeof(hdr),
-			   hdr.size_in - sizeof(hdr))) {
+	if (copy_from_user(buf, (void *)arg, hdr.size_in)) {
 		ret = -EFAULT;
 		goto out;
 	}
-- 
2.31.1