#!/usr/bin/env bash # Unofficial Bash strict mode set \ -o errexit \ -o errtrace \ -o noglob \ -o nounset \ -o pipefail IFS=$'\n\t' shopt -s inherit_errexit determine_colored_output() { declare -gl COLORED_STDOUT COLORED_STDERR readonly GREEN='\033[0;32m' readonly RED='\033[0;31m' readonly COLOR_DEFAULT='\033[0m' if [[ -v NO_COLOR || ${TERM-} == dumb ]]; then COLORED_STDOUT=false COLORED_STDERR=false else [[ -t 1 ]] || COLORED_STDOUT=false [[ -t 2 ]] || COLORED_STDERR=false fi } exit_with_error() { local error_prefix=error:$'\t\t' [[ ${COLORED_STDERR-} != false ]] && local -r COLORED_ERROR_MSG=${RED}${error_prefix}${*}${COLOR_DEFAULT} # We will have closed file descriptor 2 unless verbosity was requested, so we # will try to use FD5 (the FD that stderr was likely redirected to), and # fallback to FD2 if FD5 wasn't opened yet. if [[ -f /dev/fd/5 ]]; then exec >&5 else exec >&2 fi printf '%b\n' "${COLORED_ERROR_MSG:-${error_prefix}${@}}" exit 1 } check_for_dependencies() { if ((BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] < 3 || BASH_VERSINFO[0] < 4)); then exit_with_error "${0##*/} requires Bash 4.3+." fi if ! { command -v openssl >&- && [[ $(openssl version || true) =~ ^OpenSSL\ ([[:digit:]]+)\.([[:digit:]]+) ]] && ((BASH_REMATCH[1] == 1 && BASH_REMATCH[2] >= 1 || BASH_REMATCH[1] > 1)); }; then # shellcheck disable=2016 exit_with_error \ "${0##*/} requires OpenSSL 1.1.0+," \ 'but it is not available on $PATH.' fi } parse_cli_options() { local -r cli_options=" Usage: ${0} [-c/--certbot-dir DIRECTORY] [-f/--force-update] \\ [-h/--help] [-l/--no-color] [-n/--cert-name NAME[,NAME...] \\ [-u/--ocsp-responder URL]] [-o/--output-dir DIRECTORY] \\ [-q/--quiet|-v/--verbose] [-w/--no-reload-webserver] " print_option_error() { local reason=${1} option=${2} shift 2 local option_error="${option}: " case ${reason} in --conflict) local second_option=${1} shift option_error+="This option cannot be combined with the option ${second_option}." ;; --duplicate) option_error+="This option cannot be specified multiple times." ;; --unknown) option_error+="Invalid option." ;; --value) option_error+="This option requires a value." ;; *) exit 1 ;; esac exit_with_error "${option_error}" "${cli_options}" } declare -gl ERROR_ENCOUNTERED declare -gi VERBOSITY=${VERBOSITY:-1} while ((${#} > 0)); do local parameter=${1} case ${parameter} in -[^-]?*) set -- "-${parameter:1:1}" "-${parameter:2}" "${@:2}" ;; -c | --certbot-dir | --certbot-dir=?*) if [[ -v CERTBOT_DIR ]]; then print_option_error --duplicate "${parameter}" fi if [[ ${parameter} =~ --certbot-dir=(.+) ]]; then CERTBOT_DIR=${BASH_REMATCH[1]} else if [[ -n ${2-} ]]; then CERTBOT_DIR=${2} shift else print_option_error --value "${parameter}" fi fi CERTBOT_DIR=$( realpath \ --canonicalize-missing \ --relative-base . \ -- "${CERTBOT_DIR}" echo x ) CERTBOT_DIR=${CERTBOT_DIR%??} shift ;; -f | --force-update) if [[ ! -v FORCE_UPDATE ]]; then declare -glr FORCE_UPDATE=true fi shift ;; -h | --help) { printf '%s\n' certbot-ocsp-fetcher printf '%s\n' "${cli_options}" local absolute_tool_path absolute_tool_path=$(realpath --no-symlinks -- "${0}") readonly absolute_tool_path cat <<EOSTRING certbot-ocsp-fetcher helps you setup OCSP stapling in nginx. The tool primes nginx's OCSP cache to work around nginx's flawed OCSP stapling implementation. The tool does this by fetching and saving OCSP responses for TLS certificates issued with Certbot. --- Example: 1. Fetch OCSP responses for all certificates managed by Certbot, and save them in the current working directory. This should usually be run on a schedule, e.g. as a cronjob or systemd timer. $ ${0} 2. Add the path(s) to the resulting OCSP response(s) as the value of the ssl_stapling_file directive in the corresponding vhosts in Nginx. Don't forget to reload Nginx afterwards. 3. Re-issue all certificates managed by Certbot, to add the OCSP Must-Staple flag to the certs and automatically run certbot-ocsp-fetcher during renewals: $ certbot renew --deploy-hook ${absolute_tool_path} --force-renewal --must-staple --- See the online README for an explanation of all the CLI options: https://github.com/tomwassenberg/certbot-ocsp-fetcher/blob/main/README.md EOSTRING } exit ;; -l | --no-color) readonly COLORED_STDOUT=false COLORED_STDERR=false ;; -n | --cert-name | --cert-name=?*) if [[ ${parameter} =~ --cert-name=(.+) ]]; then local cert_lineages_value=${BASH_REMATCH[1]} shift else if [[ -n ${2-} ]]; then local cert_lineages_value=${2} shift 2 else print_option_error --value "${parameter}" fi fi # Loop over any lineages passed in the same value of --cert-name. OLDIFS=${IFS} IFS=, declare -Ag CERT_LINEAGES # Check if a hardcoded OCSP responder was specified for this set of # lineages. case ${1-} in -u | --ocsp-responder) if [[ -n ${2-} ]]; then for lineage_name in ${cert_lineages_value}; do CERT_LINEAGES["${lineage_name}"]=${2} done shift else print_option_error --value "${parameter}" fi shift ;; --ocsp-responder=?*) [[ ${1} =~ --ocsp-responder=(.+) ]] for lineage_name in ${cert_lineages_value}; do CERT_LINEAGES["${lineage_name}"]=${BASH_REMATCH[1]} done shift ;; *) # If no OCSP responder was specified, just save the lineage # name as the key, with an empty value. for lineage_name in ${cert_lineages_value}; do CERT_LINEAGES["${lineage_name}"]= done ;; esac unset lineage_name cert_lineages_value IFS=${OLDIFS} ;; -o | --output-dir | --output-dir=?*) if [[ -v OUTPUT_DIR ]]; then print_option_error --duplicate "${parameter}" fi if [[ ${parameter} =~ --output-dir=(.+) ]]; then OUTPUT_DIR=${BASH_REMATCH[1]} else if [[ -n ${2-} ]]; then OUTPUT_DIR=${2} shift else print_option_error --value "${parameter}" fi fi OUTPUT_DIR=$( realpath \ --canonicalize-missing \ --relative-base . \ -- "${OUTPUT_DIR}" echo x ) OUTPUT_DIR=${OUTPUT_DIR%??} shift ;; -q | --quiet) if ((VERBOSITY != 1)); then print_option_error --conflict "${parameter}" -v/--verbose else readonly VERBOSITY=0 shift fi ;; -v | --verbose) if ((VERBOSITY == 0)); then print_option_error --conflict "${parameter}" -q/--quiet else VERBOSITY+=1 shift fi ;; -w | --no-reload-webserver) if [[ ! -v RELOAD_WEBSERVER ]]; then declare -glr RELOAD_WEBSERVER=false fi shift ;; *) print_option_error --unknown "${parameter}" ;; esac done # Respect the common "DEBUG" environment variable if set, unless the --quiet # or --verbose flag has been passed as well. if ((${DEBUG:-0} >= 1)) && ((VERBOSITY == 1)); then # We set VERBOSITY to 0 in case of --quiet, so use the value of $DEBUG # incremented with 1 to match it with $VERBOSITY. VERBOSITY=$((DEBUG + 1)) fi # When not parsed, the stdout and/or stderr output of all external commands # we call in the script is redirected to file descriptor 3. Depending on the # desired verbosity, we redirect this file descriptor to either stderr or to # /dev/null. if ((VERBOSITY >= 2)); then exec 3>&2 else exec 3>/dev/null fi # First copy file descriptor 2 to a new FD, so stderr can still be used # (unconditionally) in the exit_with_error function. exec 5>&2 if ((VERBOSITY < 1)); then exec 2>/dev/null fi } # Set output directory if necessary and check if it's writeable prepare_output_dir() { if [[ -v OUTPUT_DIR ]]; then if [[ ! -e ${OUTPUT_DIR} ]]; then # Don't yet fail if it's not possible to create the directory, so we can # exit with a custom error down below mkdir \ --parents \ -- "${OUTPUT_DIR}" || true fi else # Use $CACHE_DIRECTORY if set (e.g. when run as a systemd service), # otherwise the working directory readonly OUTPUT_DIR=${CACHE_DIRECTORY:-.} fi if [[ ! -w ${OUTPUT_DIR} ]]; then exit_with_error "no write access to output directory (\"${OUTPUT_DIR}\")" fi } start_in_correct_mode() { # Create temporary directory to store OCSP staple file, # before having checked the certificate status in the response local temp_output_dir temp_output_dir=$(mktemp --directory) readonly temp_output_dir trap "rm -r -- ""${temp_output_dir}" EXIT declare -A lineages_processed # These two environment variables are set if this script is invoked by Certbot if [[ ! -v RENEWED_DOMAINS || ! -v RENEWED_LINEAGE ]]; then run_standalone else run_as_deploy_hook fi print_and_handle_result } # Run in "check one or all certificate lineage(s) managed by Certbot" mode # $1 - Path to temporary output directory run_standalone() { printf >&2 '%s\n\n' "Running in stand-alone mode..." readonly CERTBOT_DIR=${CERTBOT_DIR:-/etc/letsencrypt} if [[ ! -r ${CERTBOT_DIR} || (-d ${CERTBOT_DIR}/live && ! -r ${CERTBOT_DIR}/live) ]]; then exit_with_error "can't access ${CERTBOT_DIR}/live" fi # Check specific lineage if passed on CLI, # or otherwise all lineages in Certbot's dir if [[ -n ${!CERT_LINEAGES[*]} ]]; then for lineage_name in "${!CERT_LINEAGES[@]}"; do if [[ -r ${CERTBOT_DIR}/live/${lineage_name} ]]; then fetch_ocsp_response \ --standalone \ "${temp_output_dir}" \ "${lineage_name}" \ "${CERT_LINEAGES["${lineage_name}"]}" else exit_with_error "can't access ${CERTBOT_DIR}/live/${lineage_name}" fi done else set +f shopt -s nullglob for lineage_dir in "${CERTBOT_DIR}"/live/*; do set -f # Skip non-directories, like Certbot's README file [[ -d ${lineage_dir} ]] || continue fetch_ocsp_response \ --standalone "${temp_output_dir}" "${lineage_dir##*/}" done unset lineage_dir fi } # Run in deploy-hook mode, only processing the passed lineage # $1 - Path to temporary output directory run_as_deploy_hook() { printf >&2 '%s\n\n' "Running as a deploy hook of Certbot..." if [[ -v CERTBOT_DIR ]]; then # The directory is already inferred from the environment variable that # Certbot passes exit_with_error \ "-c/--certbot-dir cannot be passed" \ "when run as Certbot hook" fi if [[ -v FORCE_UPDATE ]]; then # When run as deploy hook the behavior of this flag is used by default. # Therefore passing this flag would not have any effect. exit_with_error \ "-f/--force-update cannot be passed" \ "when run as Certbot hook" fi if [[ -n ${!CERT_LINEAGES[*]} ]]; then # The certificate lineage is already inferred from the environment # variable that Certbot passes exit_with_error "-n/--cert-name cannot be passed when run as Certbot hook" fi fetch_ocsp_response \ --deploy_hook "${temp_output_dir}" "${RENEWED_LINEAGE##*/}" } # Check if it's necessary to fetch a new OCSP response check_for_existing_ocsp_staple_file() { [[ -f ${OUTPUT_DIR}/${lineage_name}.der ]] || return 1 # Validate and verify the existing local OCSP staple file local existing_ocsp_response set +e existing_ocsp_response=$(openssl ocsp \ -no_nonce \ -issuer "${lineage_dir}/chain.pem" \ -cert "${lineage_dir}/cert.pem" \ -verify_other "${lineage_dir}/chain.pem" \ -respin "${OUTPUT_DIR}/${lineage_name}.der" 2>&3) local -ir existing_ocsp_response_rc=${?} set -e readonly existing_ocsp_response ((existing_ocsp_response_rc == 0)) || return 1 for existing_ocsp_response_line in ${existing_ocsp_response}; do if [[ ${existing_ocsp_response_line} =~ ^[[:blank:]]*"This Update: "(.+)$ ]]; then local -r this_update=${BASH_REMATCH[1]} elif [[ ${existing_ocsp_response_line} =~ ^[[:blank:]]*"Next Update: "(.+)$ ]]; then local -r next_update=${BASH_REMATCH[1]} fi done [[ -n ${this_update-} && -n ${next_update-} ]] || return 1 # Only continue fetching OCSP response if existing response expires within # half of its lifetime. { # The command substitutions here don't respect `set -o errexit`, but in # case any of them fail, the total command still fails unless both # substitutions print an integer. This seems very unlikely to occur, so # let's ignore this. # shellcheck disable=2312 local -ri response_lifetime_in_seconds=$(($(date +%s --date "${next_update}") - $(date +%s --date "${this_update}"))) # `set -o errexit` isn't respected here either, but we default to renewing # the OCSP response, so this is fine. # shellcheck disable=2312 (($(date +%s) < $(date +%s --date "${this_update}") + response_lifetime_in_seconds / 2)) || return 1 } } # Generate file used by ssl_stapling_file in nginx config of websites # $1 - Whether to run as a deploy hook for Certbot, or standalone # $2 - Path to temporary output directory # $3 - Name of certificate lineage # $4 - OCSP endpoint (if specified on command line) fetch_ocsp_response() { local -r temp_output_dir=${2} local -r lineage_name=${3} # This validation should be revisited once # https://github.com/certbot/certbot/issues/6127 is fixed. if [[ ${lineage_name} =~ ($'\n')|($'\t') ]]; then ERROR_ENCOUNTERED=true exit_with_error \ "Unsupported characters encountered in the following" \ "lineage name: ${lineage_name}$'\n\n'" \ "Lineage names with embedded tabs or newlines are not supported," \ "because Certbot (as of version 1.18.0) does not have well-defined" \ 'behavior on handling any "unconventional" lineage names.' fi case ${1} in --standalone) local -r lineage_dir=${CERTBOT_DIR}/live/${lineage_name} # `set -o errexit` is not respected here, but in case of failure we still # err on the safe side by renewing the OCSP staple file. # shellcheck disable=2310 if [[ ${FORCE_UPDATE-} != true ]] && check_for_existing_ocsp_staple_file; then lineages_processed["${lineage_name}"]="not updated"$'\t'"valid staple file on disk" return fi ;; --deploy_hook) local -r lineage_dir=${RENEWED_LINEAGE} ;; *) return 1 ;; esac shift 3 # Verify that the leaf certificate is still valid. If the certificate is # expired, we don't have to request a (new) OCSP response. local cert_expiry_output set +e cert_expiry_output=$(openssl x509 \ -in "${lineage_dir}/cert.pem" \ -checkend 0 \ -noout 2>&3) local -ri cert_expiry_rc=${?} set -e if ((cert_expiry_rc != 0)); then ERROR_ENCOUNTERED=true lineages_processed["${lineage_name}"]="failed to update" if [[ ${cert_expiry_output} == "Certificate will expire" ]]; then lineages_processed["${lineage_name}"]+=$'\t'"leaf certificate expired" fi return fi local ocsp_endpoint if [[ -n ${1-} ]]; then ocsp_endpoint=${1} else ocsp_endpoint=$(openssl x509 \ -noout \ -ocsp_uri \ -in "${lineage_dir}/cert.pem" \ 2>&3) fi # Request, verify and temporarily save the actual OCSP response, # and check whether the certificate status is "good" local ocsp_call_output set +e ocsp_call_output=$(openssl ocsp \ -no_nonce \ -url "${ocsp_endpoint}" \ -issuer "${lineage_dir}/chain.pem" \ -cert "${lineage_dir}/cert.pem" \ -verify_other "${lineage_dir}/chain.pem" \ -respout "${temp_output_dir}/${lineage_name}.der" 2>&3) local -ir ocsp_call_rc=${?} set -e readonly ocsp_call_output=${ocsp_call_output#"${lineage_dir}"/cert.pem: } local -r cert_status=${ocsp_call_output%%$'\n'*} if [[ ${ocsp_call_rc} != 0 || ${cert_status} != good ]]; then ERROR_ENCOUNTERED=true lineages_processed["${lineage_name}"]="failed to update" if ((VERBOSITY >= 2)); then lineages_processed["${lineage_name}"]+=$'\t'"${ocsp_call_output//[[:space:]]/ }" else lineages_processed["${lineage_name}"]+=$'\t'"${cert_status}" fi return fi # If arrived here status was good, so move OCSP staple file to definitive # folder mv "${temp_output_dir}/${lineage_name}.der" "${OUTPUT_DIR}/" lineages_processed["${lineage_name}"]=updated } print_and_handle_result() { local -r header=LINEAGE$'\t'RESULT$'\t'REASON local lineages_processed_marked_up for lineage_name in "${!lineages_processed[@]}"; do lineages_processed_marked_up+=$'\n'"${lineage_name}"$'\t' if [[ ${COLORED_STDOUT-} != false ]]; then if [[ ${lineages_processed["${lineage_name}"]} =~ ^updated ]]; then lineages_processed_marked_up+=${GREEN} elif [[ ${lineages_processed["${lineage_name}"]} =~ ^"failed to update" ]]; then lineages_processed_marked_up+=${RED} fi lineages_processed_marked_up+=${lineages_processed["${lineage_name}"]}${COLOR_DEFAULT} else lineages_processed_marked_up+=${lineages_processed["${lineage_name}"]} fi done unset lineage_name lineages_processed_marked_up=$(sort <<<"${lineages_processed_marked_up-}") readonly lineages_processed_marked_up if [[ ${RELOAD_WEBSERVER-} != false ]]; then reload_webserver fi local output=${header}${lineages_processed_marked_up-}${nginx_status-} if ((VERBOSITY >= 1)); then local output_table # shellcheck disable=2016 output_table=$(column \ --output-separator $'\t' \ --separator $'\t' \ --table \ <<<"${output}" \ 2>/dev/null) || output_table=$(column -s$'\t' -t <<<"${output}" 2>/dev/null) || local -r column_error=($'\n' 'Install the BSD utility `column` for properly formatted output.' 'If the version of `column` supports the `--output-separator` flag,' 'the output will be formatted as TSV.' $'\n' ) readonly output=${output_table:-${output}} unset output_table # Extract header to direct it to stderr printf '%s\n' "${output%%$'\n'*}" >&2 # Remove header before printing everything else to stdout [[ -n ${!lineages_processed[*]} ]] && printf '%b\n' "${output#*$'\n'}" if [[ ${COLORED_STDERR-} != false ]]; then printf %b "${RED}${column_error[*]-}${COLOR_DEFAULT}" >&2 else printf %b "${column_error[*]-}" >&2 fi fi [[ ${ERROR_ENCOUNTERED-} != true ]] } reload_webserver() { for lineage_name in "${!lineages_processed[@]}"; do if [[ ${lineages_processed["${lineage_name}"]} == updated ]]; then local nginx_status if nginx -s reload >&3 2>&1; then [[ ${COLORED_STDERR-} != false ]] && nginx_status=${GREEN} # The last line includes a leading space, to workaround the lack of the # `-n` flag in later versions of `column`. nginx_status+=$'\n\n \t'"nginx reloaded" else ERROR_ENCOUNTERED=true [[ ${COLORED_STDERR-} != false ]] && nginx_status=${RED} nginx_status=$'\n\n \t'"nginx not reloaded"$'\t'"unable to reload nginx service, try manually" fi [[ ${COLORED_STDERR-} != false ]] && readonly nginx_status+=${COLOR_DEFAULT} break fi done unset lineage_name } main() { check_for_dependencies determine_colored_output parse_cli_options "${@}" prepare_output_dir start_in_correct_mode } main "${@}"