Don't allow CDN's to send cached responses

A lot of CA's use a CDN service to protect and speed up their ACME service. These CDN services can sometimes miss-behave and send cached results. For example DigiCert's ACME service uses the Imperva CDN. It will send cached results on the DNS validation, challenge endpoint, resulting in it being stuck in the processing status, thus dehydrated is hung and never gets the certificate.

diff --git a/dehydrated b/dehydrated
index 6e4909cbf6e69912ff002cece1610f5d5f6c459e..4548afe863c401958df0d74110d68ad8d7d4a759 100755 (executable)
--- a/dehydrated
+++ b/dehydrated
@@ -935,14 +935,14 @@ http_request() {
   set +e
   # shellcheck disable=SC2086
   if [[ "${1}" = "head" ]]; then
-    statuscode="$(curl ${ip_version:-} ${CURL_OPTS} -A "dehydrated/${VERSION} curl/${CURL_VERSION}" -s -w "%{http_code}" -o "${tempcont}" "${2}" -I)"
+    statuscode="$(curl ${ip_version:-} ${CURL_OPTS} -A "dehydrated/${VERSION} curl/${CURL_VERSION}" -s -w "%{http_code}" -o "${tempcont}" -H 'Cache-Control: no-cache' "${2}" -I)"
     curlret="${?}"
     touch "${tempheaders}"
   elif [[ "${1}" = "get" ]]; then
-    statuscode="$(curl ${ip_version:-} ${CURL_OPTS} -A "dehydrated/${VERSION} curl/${CURL_VERSION}" -L -s -w "%{http_code}" -o "${tempcont}" -D "${tempheaders}" "${2}")"
+    statuscode="$(curl ${ip_version:-} ${CURL_OPTS} -A "dehydrated/${VERSION} curl/${CURL_VERSION}" -L -s -w "%{http_code}" -o "${tempcont}" -D "${tempheaders}" -H 'Cache-Control: no-cache' "${2}")"
     curlret="${?}"
   elif [[ "${1}" = "post" ]]; then
-    statuscode="$(curl ${ip_version:-} ${CURL_OPTS} -A "dehydrated/${VERSION} curl/${CURL_VERSION}" -s -w "%{http_code}" -o "${tempcont}" "${2}" -D "${tempheaders}" -H 'Content-Type: application/jose+json' -d "${3}")"
+    statuscode="$(curl ${ip_version:-} ${CURL_OPTS} -A "dehydrated/${VERSION} curl/${CURL_VERSION}" -s -w "%{http_code}" -o "${tempcont}" "${2}" -D "${tempheaders}" -H 'Cache-Control: no-cache' -H 'Content-Type: application/jose+json' -d "${3}")"
     curlret="${?}"
   else
     set -e