88 lines
2.9 KiB
Nix
88 lines
2.9 KiB
Nix
# security tweaks borrowed from @hlissner
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{
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boot.kernel.sysctl = {
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# The Magic SysRq key is a key combo that allows users connected to the
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# system console of a Linux kernel to perform some low-level commands.
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## TCP hardening
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# Prevent bogus ICMP errors from filling up logs.
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"net.ipv4.icmp_ignore_bogus_error_responses" = 1;
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# Reverse path filtering causes the kernel to do source validation of
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# packets received from all interfaces. This can mitigate IP spoofing.
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"net.ipv4.conf.default.rp_filter" = 1;
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"net.ipv4.conf.all.rp_filter" = 1;
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# Do not accept IP source route packets (we're not a router)
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"net.ipv4.conf.all.accept_source_route" = 0;
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"net.ipv6.conf.all.accept_source_route" = 0;
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# Don't send ICMP redirects (again, we're not a router)
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"net.ipv4.conf.all.send_redirects" = 0;
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"net.ipv4.conf.default.send_redirects" = 0;
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# Refuse ICMP redirects (MITM mitigations)
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"net.ipv4.conf.all.accept_redirects" = 0;
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"net.ipv4.conf.default.accept_redirects" = 0;
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"net.ipv4.conf.all.secure_redirects" = 0;
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"net.ipv4.conf.default.secure_redirects" = 0;
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"net.ipv6.conf.all.accept_redirects" = 0;
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"net.ipv6.conf.default.accept_redirects" = 0;
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# Protects against SYN flood attacks
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"net.ipv4.tcp_syncookies" = 1;
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# Incomplete protection again TIME-WAIT assassination
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"net.ipv4.tcp_rfc1337" = 1;
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## TCP optimization
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# TCP Fast Open is a TCP extension that reduces network latency by packing
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# data in the sender’s initial TCP SYN. Setting 3 = enable TCP Fast Open for
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# both incoming and outgoing connections:
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"net.ipv4.tcp_fastopen" = 3;
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# Enable IPv4 forwarding for VPN/container routing
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"net.ipv4.ip_forward" = 1;
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# Bufferbloat mitigations + slight improvement in throughput & latency
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"net.ipv4.tcp_congestion_control" = "bbr";
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"net.core.default_qdisc" = "cake";
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## Network performance optimizations
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# Increase network buffer sizes
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"net.core.rmem_default" = 262144;
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"net.core.rmem_max" = 134217728;
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"net.core.wmem_default" = 262144;
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"net.core.wmem_max" = 134217728;
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# TCP buffer sizes
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"net.ipv4.tcp_rmem" = "4096 131072 134217728";
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"net.ipv4.tcp_wmem" = "4096 65536 134217728";
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# TCP performance
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"net.ipv4.tcp_window_scaling" = 1;
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"net.ipv4.tcp_timestamps" = 1;
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"net.ipv4.tcp_sack" = 1;
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"net.ipv4.tcp_fack" = 1;
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"net.ipv4.tcp_low_latency" = 1;
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"net.ipv4.tcp_adv_win_scale" = 1;
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# Reduce TIME_WAIT sockets
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"net.ipv4.tcp_fin_timeout" = 15;
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"net.ipv4.tcp_tw_reuse" = 1;
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};
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boot.kernelModules = ["tcp_bbr"];
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security = {
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# allow wayland lockers to unlock the screen
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# userland niceness
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rtkit.enable = true;
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polkit.enable = true;
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sudo-rs = {
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enable = true;
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execWheelOnly = true;
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wheelNeedsPassword = false;
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};
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# don't ask for password for wheel group
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sudo = {
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wheelNeedsPassword = false;
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};
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};
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}
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