scsi: qedf: Ensure the copied buf is NUL terminated

Currently, we allocate a count-sized kernel buffer and copy count from
userspace to that buffer. Later, we use kstrtouint on this buffer but we
don't ensure that the string is terminated inside the buffer, this can
lead to OOB read when using kstrtouint. Fix this issue by using
memdup_user_nul instead of memdup_user.

Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
Signed-off-by: Bui Quang Minh <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/qedf/qedf_debugfs.c

···
 	if (!count || *ppos)
 		return 0;
 
-	kern_buf = memdup_user(buffer, count);
+	kern_buf = memdup_user_nul(buffer, count);
 	if (IS_ERR(kern_buf))
 		return PTR_ERR(kern_buf);