[TLS] cert-staple.sh - refresh OCSP responses (#2469)

convenience script that can be run periodically from scheduled job
to refresh OCSP responses used for OCSP stapling

doc/scripts/Makefile.am

@@ -1,4 +1,5 @@
 EXTRA_DIST= \
+	cert-staple.sh \
 	create-mime.conf.pl \
 	rrdtool-graph.sh \
 	spawn-php.sh

doc/scripts/cert-staple.sh

@@ -0,0 +1,63 @@
+#!/bin/sh
+
+CERT_PEM="$1"   # input (cert.pem)
+CHAIN_PEM="$2"  # input (chain.pem)
+OCSP_DER="$3"   # output symlink (staple.der)
+
+OCSP_TMP=""     # temporary file
+
+if [[ -z "$CERT_PEM" ]] || [[ -z "$CHAIN_PEM" ]] || [[ -z "$OCSP_DER" ]] \
+   || [[ ! -f "$CERT_PEM" ]] || [[ ! -f "$CHAIN_PEM" ]]; then
+    echo 1>&2 "usage: cert-staple.sh cert.pem chain.pem staple.der"
+    exit 1
+fi
+
+function errexit {
+    [[ -n "$OCSP_TMP" ]] && rm -f "$OCSP_TMP"
+    exit 1
+}
+
+# get URI of OCSP responder from certificate
+OCSP_URI=$(openssl x509 -in "$CERT_PEM" -ocsp_uri -noout)
+[[ $? = 0 ]] && [[ -n "$OCSP_URI" ]] || exit 1
+
+# get OCSP response from OCSP responder
+OCSP_TMP="$OCSP_DER.$$"
+OCSP_RESP=$(openssl ocsp -issuer "$CHAIN_PEM" -cert "$CERT_PEM" -respout "$OCSP_TMP" -noverify -no_nonce -url "$OCSP_URI")
+[[ $? = 0 ]] || errexit
+
+# parse OCSP response from OCSP responder
+#
+#$CERT_PEM: good
+#        This Update: Jun  5 21:00:00 2020 GMT
+#        Next Update: Jun 12 21:00:00 2020 GMT
+
+ocsp_status="$(printf %s "$OCSP_RESP" | head -1)"
+[[ "$ocsp_status" = "$CERT_PEM: good" ]] || errexit
+
+next_update="$(printf %s "$OCSP_RESP" | grep 'Next Update:')"
+next_date="$(printf %s "$next_update" | sed 's/.*Next Update: //')"
+[[ -n "$next_date" ]] || errexit
+ocsp_expire=$(date -d "$next_date" +%s)
+
+# validate OCSP response
+ocsp_verify=$(openssl ocsp -issuer "$CHAIN_PEM" -cert "$CERT_PEM" -respin "$OCSP_TMP" -no_nonce -out /dev/null 2>&1)
+[[ "$ocsp_verify" = "Response verify OK" ]] || errexit
+
+# rename and update symlink to install OCSP response to be used in OCSP stapling
+OCSP_OUT="$OCSP_DER.$ocsp_expire"
+mv "$OCSP_TMP" "$OCSP_OUT" || errexit
+OCSP_TMP=""
+ln -sf "${OCSP_OUT##*/}" "$OCSP_DER" || errexit
+
+# debug: display text output of OCSP .der file
+#openssl ocsp -respin "$OCSP_DER" -resp_text -noverify
+
+# remove old OCSP responses which have expired
+now=$(date +%s)
+for i in "$OCSP_DER".*; do
+    ts="${i#${OCSP_DER}.}"
+    if [[ -n "$ts" ]] && [[ "$ts" -lt "$now" ]]; then
+        rm -f "$i"
+    fi
+done