[PATCH] USB: usbtmc: prevent kernel-infoleak

[Edward Adam Davis]

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=9d34f80f841e948c3fdb
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 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 6bd9fe565385..e9ddaa9b580d 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -759,6 +759,7 @@ static struct urb *usbtmc_create_urb(void)
 		usb_free_urb(urb);
 		return NULL;
 	}
+	memset(dmabuf, 0, bufsize);
 
 	urb->transfer_buffer = dmabuf;
 	urb->transfer_buffer_length = bufsize;
-- 
2.43.0