mixandClaude Opus 5.5
599149bf83
Comments only, no behaviour changed. Each main.cf/master.cf parameter the
build sets, the wrapper's and the reload hook's reliance on Postfix 3.7.11
(postfix-script, master.5, postconf.5, cleanup_init.c, smtpd_peer.c,
README_FILES), supervisor 4.2.5 (process.py, options.py, events.rst),
logrotate 3.21.0, OpenDKIM's config, Cyrus SASL's sasldb, rspamd 3.11.1
(milter_headers.lua, multimap, the map watcher), Docker Compose, CoreDNS
and certbot now say where that is written. Measurements already there stay
measurements ("date not recorded" where none was); hand-composed fixtures
say so.
Contradictions left for their own commits: C-P31 cleanup's size limit,
C-P42 master outside supervisor's signal, C-V5/V6 startsecs, C-V10,
C-S3/Q3 sasldb written in place, C-Q4/A1 certbot's symlinks, C-R7 rspamd
skips local clients but the signature routine does not, C-P8, C-R4, C-R12,
C-M7, C-E2, C-K8/K9, C-D1.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
91 lines
3.5 KiB
Bash
91 lines
3.5 KiB
Bash
#!/bin/sh
|
|
# Picks up a renewed TLS certificate while the container runs (spec 5.2 p.4;
|
|
# audit 2026-10-12, H2).
|
|
#
|
|
# Postfix does not read the mounted files: postfix-config.sh copies them at
|
|
# start into /etc/postfix/tls-internal, because Postfix wants the key owned by
|
|
# root with mode 0600, which a read-only bind mount owned by the host's user
|
|
# cannot give. A renewal of the mounted files therefore reaches Postfix only
|
|
# through a new copy. Every interval this compares the mounted files with the
|
|
# copy; when they differ it copies both beside their targets, checks that the
|
|
# copies - not the mounted files, which a renewer may be rewriting - are a
|
|
# certificate and the key that belongs to it, renames both over the targets
|
|
# and reloads Postfix. When nothing changed it does nothing.
|
|
# (Postfix 3.7.11: smtpd loads the certificate in pre_jail_init(), once per
|
|
# process, src/smtpd/smtpd.c; "postfix reload" is SIGHUP to master,
|
|
# conf/postfix-script, after which the old smtpd processes exit on the closed
|
|
# status pipe, src/master/master_conf.c, master_config() ->
|
|
# master_restart_service(), and new ones load the files again.)
|
|
#
|
|
# Runs under supervisord as root. It sleeps first: at container start the
|
|
# wrapper is still bringing Postfix up. It never exits non-zero, so a failure
|
|
# does not trip the crashexit listener; it is logged and tried again.
|
|
set -u
|
|
umask 077 # the key's copy is never readable by others, not even for an instant
|
|
|
|
INTERVAL="${TLS_RELOAD_INTERVAL_SECONDS:-86400}"
|
|
SRC_CERT="${TLS_CERT_FILE:-/etc/postfix/tls/fullchain.pem}"
|
|
SRC_KEY="${TLS_KEY_FILE:-/etc/postfix/tls/privkey.pem}"
|
|
DIR=/etc/postfix/tls-internal
|
|
CERT="$DIR/fullchain.pem"
|
|
KEY="$DIR/privkey.pem"
|
|
PENDING=0 # a copy was renewed and Postfix has not been reloaded since
|
|
|
|
reload() {
|
|
if postfix reload; then
|
|
echo "cert-reload: postfix reloaded ($1)"
|
|
PENDING=0
|
|
else
|
|
echo "cert-reload: postfix reload failed, will try again after ${INTERVAL}s" >&2
|
|
fi
|
|
}
|
|
|
|
# same_pair says whether a certificate file and a private key file belong
|
|
# together.
|
|
same_pair() {
|
|
cert_pub=$(openssl x509 -noout -pubkey -in "$1" 2>/dev/null) || return 1
|
|
key_pub=$(openssl pkey -pubout -in "$2" 2>/dev/null) || return 1
|
|
[ -n "$cert_pub" ] && [ "$cert_pub" = "$key_pub" ]
|
|
}
|
|
|
|
refresh() {
|
|
if [ "$PENDING" = 1 ]; then
|
|
reload "renewed certificate, earlier reload had failed"
|
|
fi
|
|
if [ "$(postconf -h smtpd_tls_cert_file 2>/dev/null)" != "$CERT" ]; then
|
|
# Postfix reads the mounted files themselves (they were missing at
|
|
# start, so no copy was made): a reload is what picks up a change.
|
|
reload "periodic TLS refresh"
|
|
return
|
|
fi
|
|
if [ ! -r "$SRC_CERT" ] || [ ! -r "$SRC_KEY" ]; then
|
|
echo "cert-reload: cannot read ${SRC_CERT} or ${SRC_KEY}; Postfix keeps the certificate it has" >&2
|
|
return
|
|
fi
|
|
if cmp -s "$SRC_CERT" "$CERT" && cmp -s "$SRC_KEY" "$KEY"; then
|
|
return
|
|
fi
|
|
rm -f "$CERT.new" "$KEY.new"
|
|
if ! cp "$SRC_CERT" "$CERT.new" || ! cp "$SRC_KEY" "$KEY.new"; then
|
|
rm -f "$CERT.new" "$KEY.new"
|
|
echo "cert-reload: copying the renewed certificate failed, will try again after ${INTERVAL}s" >&2
|
|
return
|
|
fi
|
|
if ! same_pair "$CERT.new" "$KEY.new"; then
|
|
rm -f "$CERT.new" "$KEY.new"
|
|
echo "cert-reload: the mounted certificate and key differ from Postfix's copy but do not belong together; will look again after ${INTERVAL}s" >&2
|
|
return
|
|
fi
|
|
chown root:root "$CERT.new" "$KEY.new"
|
|
chmod 0644 "$CERT.new"
|
|
chmod 0600 "$KEY.new"
|
|
mv -f "$KEY.new" "$KEY" && mv -f "$CERT.new" "$CERT"
|
|
PENDING=1
|
|
reload "renewed certificate"
|
|
}
|
|
|
|
while true; do
|
|
sleep "${INTERVAL}"
|
|
refresh
|
|
done
|