Files
selfpost/build/logrotate-loop.sh
T
mixandClaude Opus 5.5 a39eda5a0b audit 5: findings of the two reviews
- The e2e's numeric-settings test ran a container that passed every gate
  and never ended: the good values are checked beside a bad one after
  them; each run is named, bounded to a minute and removed.
- The gates refuse a value under the parameter's minimum (a zero window
  kills anvil, a zero milter timeout smtpd) and one past an int, in
  seconds for a time value (src/global/conv_time.c, src/anvil/anvil.c).
- OpenDKIM waits, five seconds at most, for the relay's socket.
- The relay marks its lines `syslog: `, writes control characters out,
  reads into a queue at once and drops past 200 lines a second, saying
  how many (security F1, F2; a stuck relay would hold OpenDKIM in
  syslog(3)).
- smtp_tls_mandatory_protocols >=TLSv1.2 too.
- extract-cert.sh keeps the old files' group and sets its trap before
  mktemp.
- crashexit spares cert-reload; architecture.md "four times running" and
  what else exits the container; security.md the restart after five panel
  exits and the /dev/log socket.
- Measured against the technical review: smtpd has the selfpost group
  (Groups 104 998), so it did reach the supervisor socket before this
  stage.
Accepted, reasons in the plan: the logrotate state file in the postfix
user's directory, envdoc_test's reading of `${VAR:-}` only, crashexit's
window pruning untested.

Tested on the test server: go vet + go test of 27 packages, make e2e (all
pass, 592 s) on this tree.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-15 13:53:14 +03:00

88 lines
3.5 KiB
Bash

#!/bin/sh
# Periodic logrotate for /data/log/mail.log. Rotation renames the file,
# recreates it (`create 0640 postfix selfpost`, matching a cold container
# start), then runs `postfix reload` (the same mechanism `postfix logrotate`
# uses): postlogd keeps writing to the renamed inode until reload, and the
# panel's log-tailer holds its own descriptor on that inode, so nothing written
# before the reload is lost. `create` (rather than `nocreate`) matters here
# beyond timing: a postlogd-triggered recreate lands the file at 0600 owned by
# postfix, which the unprivileged panel process cannot read — confirmed on a
# live container (date not recorded), and so in the source: Postfix 3.7.11,
# src/util/logwriter.c, logwriter_open_or_die(), creates it 0644 under master's
# umask(077), src/master/master.c — so logrotate must be the one to create it.
# The reload: Postfix 3.7.11, conf/postfix-script, "logrotate" (mv, then kill
# -HUP master); master_conf.c, master_config() -> master_restart_service() ->
# master_status_cleanup(), on which postlogd exits (src/master/dgram_server.c,
# dgram_server_abort() on MASTER_STATUS_FD), and the next postlogd opens the
# path anew (src/postlogd/postlogd.c, logwriter_open_or_die()).
#
# logrotate itself only rotates once the configured "daily" period has elapsed
# (tracked in its state file), so it is safe to invoke this more often than
# daily — polling merely bounds how late a legitimate rotation runs. The state
# file is beside the log, under /data, not at the default
# /var/lib/logrotate/status (logrotate 3.21.0-1: debian/rules,
# --with-state-file-path) in the container's own filesystem: a recreated
# container started without it, logrotate.c, newState(), records a log it has
# no state for as rotated today, and so a host that recreates the container
# daily - an .env change, an image bump - never rotated mail.log at all (audit
# 2026-10-12, M19). (logrotate 3.21.0, logrotate.8.in: "-s, --state
# statefile".) The directory is postfix:selfpost 2750 and logrotate runs as
# root.
set -eu
CONFIG=/etc/logrotate.d/mail
STATE=/data/log/.logrotate.status
INTERVAL="${LOGROTATE_INTERVAL_SECONDS:-21600}"
# logrotate refuses configs writable by group or others and exits 0 while
# ignoring them — fail here so supervisord reports the fault. (logrotate
# 3.21.0, config.c, readConfigFile(): as root, mode & 0022 gives "Ignoring ...
# because it is writable by group or others." and returns 0, not an error; a
# config not owned by root is ignored the same way. "Potentially dangerous
# mode" is only a warning there, for any mode & 07533 other than 0400 - this
# loop chooses to treat it as fatal too.)
logrotate_config_ok() {
mode=$(stat -c '%a' "$CONFIG")
mode=${mode#0}
grp=$(( (mode / 10) % 10 ))
oth=$(( mode % 10 ))
case $grp in 2|3|6|7) return 1 ;; esac
case $oth in 2|3|6|7) return 1 ;; esac
return 0
}
logrotate_config_fatal() {
echo "logrotate-loop: refusing to run: $CONFIG mode $(stat -c '%a' "$CONFIG") is writable by group or others" >&2
exit 1
}
if ! logrotate_config_ok; then
logrotate_config_fatal
fi
run_logrotate() {
out=$(logrotate -s "$STATE" "$CONFIG" 2>&1) || {
echo "$out" >&2
return 1
}
case "$out" in
*Ignoring*|*Potentially\ dangerous\ mode*)
echo "$out" >&2
logrotate_config_fatal
;;
esac
return 0
}
while true; do
if ! logrotate_config_ok; then
logrotate_config_fatal
fi
if run_logrotate; then
:
else
echo "logrotate-loop: logrotate failed, will retry after ${INTERVAL}s" >&2
fi
sleep "${INTERVAL}"
done