Add syncthing certificate generator script

1 files changed, 70 insertions, 0 deletions

diff --git a/scripts/syncthing-cert.sh b/scripts/syncthing-cert.sh
new file mode 100644
index 0000000..0dd460b
--- /dev/null
+++ b/scripts/syncthing-cert.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+set -e
+days="3650"
+keyout="syncthing.key"
+reqout="$(mktemp)"
+certout="syncthing.crt"
+alg="ED25519"
+
+help() {
+cat <<EOF
+$0 [ -c <certificate_out> ] [ -k <key_out> ] [ -448 ]
+Defaults are:
+certificate_out: 'syncthing.crt'
+key_out: 'syncthing.key'
+
+Optionally, the -448 option will generate an ED448 key instead of ED25519.
+
+EOF
+exit 1
+}
+
+while [ $# -gt 0 ] ; do case $1 in
+	-c) certout="$2" ; shift ; shift ;;
+	-k) keyout="$2" ; shift ; shift ;;
+	-448) alg="ED448"; shift ;;
+	*) help ;;
+esac ; done
+
+v3Section="
+basicConstraints = CA:FALSE
+keyUsage = digitalSignature, keyEncipherment, dataEncipherment
+extendedKeyUsage = serverAuth, clientAuth
+subjectAltName = @alt_names
+[alt_names]
+DNS.1 = syncthing
+"
+
+openssl genpkey -algorithm $alg > "$keyout"
+
+cnf="$(mktemp)"
+cat > "$cnf" <<EOF
+[req]
+distinguished_name = req_distinguished_name
+prompt = no
+req_extensions = v3_req
+[req_distinguished_name]
+OU = Automatically Generated
+O = Syncthing
+CN = syncthing
+[v3_req]
+$v3Section
+EOF
+
+extfile="$(mktemp)"
+cat > "$extfile" <<EOF
+[v3_ca]
+$v3Section
+EOF
+
+openssl req -new -out "$reqout" -key "$keyout" -config "$cnf"
+
+rm "$cnf"
+
+openssl x509 -req -days "$days" -in "$reqout" -signkey "$keyout" \
+	-extensions v3_ca \
+	-extfile "$extfile" \
+	-out "$certout"
+
+rm "$extfile"
+rm "$reqout"