The syzbot reported a kernel-usb-infoleak in usbtmc_write,
we need to clear the structure before filling fields.

Fixes: 4ddc645f40e9 ("usb: usbtmc: Add ioctl for vendor specific write")
Reported-and-tested-by: syzbot+9d34f80f841e948c3fdb@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9d34f80f841e948c3fdb
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
V1 -> V2: Only clear uninitialized bytes after header and data
V2 -> V3: Update condition and comments
V3 -> V4: Use kzalloc to clear up dmabuf

 drivers/usb/class/usbtmc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 619123e24c41..7866ea6dad37 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -754,7 +754,7 @@ static struct urb *usbtmc_create_urb(void)
 	if (!urb)
 		return NULL;
 
-	dmabuf = kmalloc(bufsize, GFP_KERNEL);
+	dmabuf = kzalloc(bufsize, GFP_KERNEL);
 	if (!dmabuf) {
 		usb_free_urb(urb);
 		return NULL;
-- 
2.43.0