Public Key Infrastructure - (step-certificate)

apt install wget

wget https://dl.smallstep.com/cli/docs-ca-install/latest/step-cli_amd64.deb

wget https://dl.smallstep.com/certificates/docs-ca-install/latest/step-ca_amd64.deb

sudo dpkg -i step-cli_amd64.deb

sudo dpkg -i step-ca_amd64.deb

CA init

step ca init

vi /root/.step/password.txt

ca-password

step ca provisioner add acme --type ACME

step-ca $(step path)/config/ca.json

Run as a service

useradd --user-group --system --home /etc/step-ca --shell /bin/false step

setcap CAP_NET_BIND_SERVICE=+eip $(which step-ca)

mkdir -p /etc/step-ca

mv $(step path)/* /etc/step-ca

chown -R step:step /etc/step-ca

apt install jq

cat <<< $(jq '.root = "/etc/step-ca/certs/root_ca.crt"' /etc/step-ca/config/ca.json) > /etc/step-ca/config/ca.json

cat <<< $(jq '.crt = "/etc/step-ca/certs/intermediate_ca.crt"' /etc/step-ca/config/ca.json) > /etc/step-ca/config/ca.json

cat <<< $(jq '.key = "/etc/step-ca/secrets/intermediate_ca_key"' /etc/step-ca/config/ca.json) > /etc/step-ca/config/ca.json

cat <<< $(jq '.db.dataSource = "/etc/step-ca/db"' /etc/step-ca/config/ca.json) > /etc/step-ca/config/ca.json

vi /etc/systemd/system/step-ca.service

[Unit]
Description=step-ca service
Documentation=https://smallstep.com/docs/step-ca
Documentation=https://smallstep.com/docs/step-ca/certificate-authority-server-production
After=network-online.target
Wants=network-online.target
StartLimitIntervalSec=30
StartLimitBurst=3
ConditionFileNotEmpty=/etc/step-ca/config/ca.json
ConditionFileNotEmpty=/etc/step-ca/password.txt

[Service]
Type=simple
User=step
Group=step
Environment=STEPPATH=/etc/step-ca
WorkingDirectory=/etc/step-ca
ExecStart=/usr/bin/step-ca config/ca.json --password-file password.txt
ExecReload=/bin/kill --signal HUP $MAINPID
Restart=on-failure
RestartSec=5
TimeoutStopSec=30
StartLimitInterval=30
StartLimitBurst=3

; Process capabilities & privileges
AmbientCapabilities=CAP_NET_BIND_SERVICE
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
SecureBits=keep-caps
NoNewPrivileges=yes

; Sandboxing
ProtectSystem=full
ProtectHome=true
RestrictNamespaces=true
RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
PrivateTmp=true
PrivateDevices=true
ProtectClock=true
ProtectControlGroups=true
ProtectKernelTunables=true
ProtectKernelLogs=true
ProtectKernelModules=true
LockPersonality=true
RestrictSUIDSGID=true
RemoveIPC=true
RestrictRealtime=true
SystemCallFilter=@system-service
SystemCallArchitectures=native
MemoryDenyWriteExecute=true
ReadWriteDirectories=/etc/step-ca/db

[Install]
WantedBy=multi-user.target

systemctl enable step-ca

systemctl start step-ca

On the client side

apt install wget

wget -O /usr/local/share/ca-certificates/domain.crt --no-check-certificate https://pki1.example.com/roots.pem

update-ca-certificates

apt install certbot

certbot certonly --standalone -d test1.example.com --server https://pki1.example.com/acme/acme/directory

Renew certificates

certbot renew

Certificate Duration

Change in the /etc/step-ca/config/ca.json file the maxTLSCertDuration and the defaultTLSCertDuration to increase the certificate duration.

...
  "db": {
    "type": "badgerv2",
    "dataSource": "/etc/step-ca/db",
    "badgerFileLoadingMode": ""
  },
  "authority": {
    "claims": {
      "minTLSCertDuration": "5m",
      "maxTLSCertDuration": "8640h",
      "defaultTLSCertDuration": "8640h",
      "disableRenewal": false,
      "allowRenewalAfterExpiry": false,
      "minHostSSHCertDuration": "5m",
      "maxHostSSHCertDuration": "1680h",
      "defaultHostSSHCertDuration": "720h",
      "minUserSSHCertDuration": "5m",
      "maxUserSSHCertDuration": "24h",
      "defaultUserSSHCertDuration": "16h"
    },
    "provisioners": [
...

systemctl restart step-ca