graphene-os-server-infrastr.../certbot-ocsp-fetcher
2023-07-09 18:16:59 -04:00

677 lines
20 KiB
Bash
Executable File

#!/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
} >&2
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 "${@}"
prepare_output_dir
start_in_correct_mode
}
main "${@}"