As far as I remember, L4 is such a minimal beast that you typically run something like a Linux-Kernel inside it, to do most of the boring stuff. And then use th

As far as I remember, L4 is such a minimal beast that you typically run something like a Linux-Kernel inside it, to do most of the boring stuff. And then use the guarantees on isolation provided by L4 to have timing or security critical functions into their own L4 tasks. Am I wrong there? But even if L4 would provide the minimal set of functions expected to pass packets on an embedded device like a router: Would you really gain security if you had to rewrite most of the libraries involved for, say, user-interface and configuration (where all of the exploits reside) from scratch? The whole wpa/wpa2-hostapd madness, or VPN setup with all the many dozens of possible protocol combinations? And even when one plans to rewrite hostapd, openvpn, dnsmasqd with all their dependencies from scratch, in a safer language than C, with reduced priviledges and isolated from the rest of the system: One still could run these replacements easily under a Linux kernel providing most of the necessary infrastructure and with hardly and bugs being discovered in the kernel core that would be relevant for such an embedded device.