microsandbox: Secret values exposed in world-readable process arguments
When the SDK spawns a sandbox, the msb sandbox child process receives the full network configuration as an inline –network-config <json> command-line argument, and any per-sandbox environment as repeated –env KEY=VALUE arguments. On Linux a process's arguments are world-readable via /proc/<pid>/cmdline, and on both Linux and macOS they are visible to other local processes via ps. Because the network configuration carries the real secret values used for host-side secret substitution, …