772 lines
30 KiB
Python
772 lines
30 KiB
Python
#!/usr/bin/env python3
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"""
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IMAP server (port 143).
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Full IMAP4rev1 state machine with bait mailbox.
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States: NOT_AUTHENTICATED → AUTHENTICATED → SELECTED
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Credentials via IMAP_USERS env var ("user:pass,user2:pass2").
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10 bait emails in INBOX containing AWS keys, DB passwords, tokens etc.
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Banner advertises Dovecot so nmap fingerprints correctly.
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"""
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import asyncio
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import email
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import email.policy
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import json
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import os
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import sys
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import time
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from email.utils import getaddresses
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from pathlib import Path
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from typing import cast
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from syslog_bridge import (
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SEVERITY_WARNING,
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encode_secret,
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forward_syslog,
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syslog_line,
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write_syslog_file,
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)
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NODE_NAME = os.environ.get("NODE_NAME", "mailserver")
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SERVICE_NAME = "imap"
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LOG_TARGET = os.environ.get("LOG_TARGET", "")
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PORT = int(os.environ.get("PORT", "143"))
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IMAP_BANNER = os.environ.get("IMAP_BANNER", "* OK Dovecot ready.\r\n")
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_RAW_USERS = os.environ.get("IMAP_USERS", "admin:admin123,root:toor,mail:mail,user:user")
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VALID_USERS: dict[str, str] = {
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u: p for part in _RAW_USERS.split(",") if ":" in part for u, p in [part.split(":", 1)]
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}
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# Operator/realism-engine email seed source. Two shapes accepted:
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# 1. Directory: walked recursively for ``*.eml`` (RFC 822 on disk —
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# what the realism-engine emailgen worker drops in) and ``*.json``
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# (operator-curated lists of dicts, see _load_seed_json).
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# 2. Single ``*.json`` file: a list of dicts with the same shape.
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# Loaded entries are CONCATENATED with ``_BAIT_EMAILS`` — never replace.
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# The hardcoded list keeps a fresh deployment non-silent and serves as
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# the deterministic baseline the persona output stacks on top of.
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_EMAIL_SEED_PATH = os.environ.get("IMAP_EMAIL_SEED", "")
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# Re-scan the seed directory at most this often. Cheap: walking a few
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# dozen .eml files is sub-millisecond, but caching keeps an attacker's
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# rapid LIST/FETCH burst from re-parsing the same files on every
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# command. Mtime check still triggers a re-load on real changes.
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_SEED_RESCAN_INTERVAL = float(os.environ.get("IMAP_EMAIL_SEED_RESCAN", "5"))
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# ── Bait emails ───────────────────────────────────────────────────────────────
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# All 10 live in INBOX. UID == sequence number.
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_BAIT_EMAILS: list[dict] = [
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{
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"uid": 1, "flags": [r"\Seen"],
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"from_name": "DevOps Team", "from_addr": "devops@company.internal",
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"to_addr": "admin@company.internal",
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"subject": "AWS credentials rotation",
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"date": "Mon, 06 Nov 2023 09:12:33 +0000",
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"body": (
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"Date: Mon, 06 Nov 2023 09:12:33 +0000\r\n"
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"From: DevOps Team <devops@company.internal>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: AWS credentials rotation\r\n"
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"Message-ID: <1@company.internal>\r\n"
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"\r\n"
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"Team,\r\n\r\n"
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"New AWS credentials have been issued. Old keys deactivated.\r\n\r\n"
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"Access Key ID: AKIAIOSFODNN7EXAMPLE\r\n"
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"Secret Access Key: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY\r\n\r\n"
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"Update ~/.aws/credentials immediately.\r\n\r\n-- DevOps\r\n"
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),
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},
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{
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"uid": 2, "flags": [r"\Seen"],
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"from_name": "Monitoring", "from_addr": "monitoring@company.internal",
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"to_addr": "admin@company.internal",
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"subject": "DB password changed",
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"date": "Tue, 07 Nov 2023 14:05:11 +0000",
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"body": (
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"Date: Tue, 07 Nov 2023 14:05:11 +0000\r\n"
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"From: Monitoring <monitoring@company.internal>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: DB password changed\r\n"
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"Message-ID: <2@company.internal>\r\n"
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"\r\n"
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"Production database password was rotated.\r\n\r\n"
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"Connection string: mysql://admin:Sup3rS3cr3t!@10.0.1.5:3306/production\r\n\r\n"
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"Update all app configs.\r\n"
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),
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},
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{
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"uid": 3, "flags": [],
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"from_name": "GitHub", "from_addr": "noreply@github.com",
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"to_addr": "admin@company.internal",
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"subject": "Your personal access token",
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"date": "Wed, 08 Nov 2023 08:30:00 +0000",
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"body": (
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"Date: Wed, 08 Nov 2023 08:30:00 +0000\r\n"
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"From: GitHub <noreply@github.com>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: Your personal access token\r\n"
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"Message-ID: <3@company.internal>\r\n"
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"\r\n"
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"Hi admin,\r\n\r\n"
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"A new personal access token was created for your account.\r\n\r\n"
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"Token: ghp_16C7e42F292c6912E7710c838347Ae178B4a\r\n\r\n"
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"If this wasn't you, revoke it immediately at github.com/settings/tokens.\r\n"
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),
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},
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{
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"uid": 4, "flags": [r"\Seen"],
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"from_name": "IT Admin", "from_addr": "admin@company.internal",
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"to_addr": "team@company.internal",
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"subject": "VPN config attached",
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"date": "Thu, 09 Nov 2023 11:22:47 +0000",
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"body": (
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"Date: Thu, 09 Nov 2023 11:22:47 +0000\r\n"
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"From: IT Admin <admin@company.internal>\r\n"
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"To: team@company.internal\r\n"
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"Subject: VPN config attached\r\n"
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"Message-ID: <4@company.internal>\r\n"
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"\r\n"
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"VPN access details for new starters:\r\n\r\n"
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" Host: vpn.company.internal:1194\r\n"
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" Protocol: UDP\r\n"
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" Username: vpnadmin\r\n"
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" Password: VpnP@ss2024\r\n\r\n"
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"Config file sent separately via secure channel.\r\n"
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),
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},
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{
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"uid": 5, "flags": [],
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"from_name": "SysAdmin", "from_addr": "sysadmin@company.internal",
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"to_addr": "admin@company.internal",
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"subject": "Root password",
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"date": "Fri, 10 Nov 2023 16:45:00 +0000",
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"body": (
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"Date: Fri, 10 Nov 2023 16:45:00 +0000\r\n"
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"From: SysAdmin <sysadmin@company.internal>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: Root password\r\n"
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"Message-ID: <5@company.internal>\r\n"
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"\r\n"
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"New root password for prod servers:\r\n\r\n"
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" r00tM3T00!\r\n\r\n"
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"Change after first login. Do NOT forward this email.\r\n"
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),
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},
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{
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"uid": 6, "flags": [r"\Seen"],
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"from_name": "Backup System", "from_addr": "backup@company.internal",
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"to_addr": "admin@company.internal",
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"subject": "Backup job failed",
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"date": "Sat, 11 Nov 2023 03:12:04 +0000",
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"body": (
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"Date: Sat, 11 Nov 2023 03:12:04 +0000\r\n"
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"From: Backup System <backup@company.internal>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: Backup job failed\r\n"
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"Message-ID: <6@company.internal>\r\n"
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"\r\n"
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"Nightly backup to 192.168.1.50:/mnt/nas FAILED at 03:11 UTC.\r\n\r\n"
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"Error: Authentication failed. Credentials in /etc/backup.conf may be stale.\r\n\r\n"
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"Last successful backup: 2023-11-10 03:11 UTC\r\n"
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),
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},
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{
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"uid": 7, "flags": [r"\Seen"],
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"from_name": "Security Alerts", "from_addr": "alerts@company.internal",
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"to_addr": "admin@company.internal",
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"subject": "SSH brute-force alert",
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"date": "Sun, 12 Nov 2023 07:04:31 +0000",
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"body": (
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"Date: Sun, 12 Nov 2023 07:04:31 +0000\r\n"
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"From: Security Alerts <alerts@company.internal>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: SSH brute-force alert\r\n"
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"Message-ID: <7@company.internal>\r\n"
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"\r\n"
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"47 failed SSH login attempts detected against prod-web-01.\r\n\r\n"
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"Source IPs: 185.220.101.34, 185.220.101.47, 185.220.101.52\r\n"
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"Target user: root\r\n"
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"Period: 2023-11-12 06:58 – 07:04 UTC\r\n\r\n"
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"All attempts blocked by fail2ban. No successful logins.\r\n"
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),
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},
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{
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"uid": 8, "flags": [r"\Seen"],
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"from_name": "External Vendor", "from_addr": "vendor@external.com",
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"to_addr": "admin@company.internal",
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"subject": "RE: API integration",
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"date": "Mon, 13 Nov 2023 10:11:55 +0000",
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"body": (
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"Date: Mon, 13 Nov 2023 10:11:55 +0000\r\n"
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"From: External Vendor <vendor@external.com>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: RE: API integration\r\n"
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"Message-ID: <8@company.internal>\r\n"
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"\r\n"
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"Hi,\r\n\r\n"
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"Here is the live API key for the integration:\r\n\r\n"
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" sk_live_9mK3xF2aP7qR1bN8cT4dW6vE0yU5hJ\r\n\r\n"
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"Keep this confidential. Let me know if you need the webhook secret.\r\n\r\n"
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"Best regards,\r\nVendor Support\r\n"
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),
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},
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{
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"uid": 9, "flags": [],
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"from_name": "Help Desk", "from_addr": "helpdesk@company.internal",
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"to_addr": "admin@company.internal",
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"subject": "Password reset request",
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"date": "Tue, 14 Nov 2023 13:48:22 +0000",
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"body": (
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"Date: Tue, 14 Nov 2023 13:48:22 +0000\r\n"
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"From: Help Desk <helpdesk@company.internal>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: Password reset request\r\n"
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"Message-ID: <9@company.internal>\r\n"
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"\r\n"
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"Hi,\r\n\r\n"
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"Could you reset my MFA? Current password is Winter2024! so you can verify it's me.\r\n\r\n"
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"Thanks\r\n"
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),
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},
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{
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"uid": 10, "flags": [r"\Seen"],
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"from_name": "AWS Billing", "from_addr": "noreply@aws.amazon.com",
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"to_addr": "admin@company.internal",
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"subject": "Your AWS bill is ready",
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"date": "Wed, 15 Nov 2023 00:01:00 +0000",
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"body": (
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"Date: Wed, 15 Nov 2023 00:01:00 +0000\r\n"
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"From: AWS Billing <noreply@aws.amazon.com>\r\n"
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"To: admin@company.internal\r\n"
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"Subject: Your AWS bill is ready\r\n"
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"Message-ID: <10@company.internal>\r\n"
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"\r\n"
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"Your AWS bill for October 2023 is $847.23.\r\n\r\n"
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"Top services:\r\n"
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" EC2 (us-east-1): $412.10\r\n"
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" RDS (us-east-1): $198.50\r\n"
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" S3: $87.43\r\n"
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" EC2 (eu-west-2): $149.20\r\n\r\n"
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"Account ID: 123456789012\r\n"
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),
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},
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]
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_MAILBOXES = ["INBOX", "Sent", "Drafts", "Archive"]
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# ── Spool-backed email loader ─────────────────────────────────────────────────
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# When IMAP_EMAIL_SEED points at a directory (or a single .json file) the
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# realism-engine emailgen worker / operator has populated, parse it on
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# demand and CONCATENATE the result with the hardcoded ``_BAIT_EMAILS``.
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# Cached with a short TTL + mtime check so a hot mailbox doesn't pay the
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# parse cost on every IMAP command.
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_seed_cache: list[dict] | None = None
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_seed_cache_path_mtime: float = 0.0
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_seed_cache_loaded_at: float = 0.0
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_SEED_JSON_REQUIRED = ("from_addr", "to_addr", "subject", "body")
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def _split_addr(value: str) -> tuple[str, str]:
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"""Return (display_name, email) from a header value, falling back to
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the raw string when the parse fails. Worker side; we don't need
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real RFC 5322 — just enough to populate the IMAP envelope tuple."""
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if not value:
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return "", ""
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pairs = getaddresses([value])
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if not pairs:
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return "", value
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name, addr = pairs[0]
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return (name or "").strip(), (addr or value).strip()
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def _eml_to_dict(path: Path) -> dict | None:
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"""Parse one .eml into the dict shape the rest of this server uses.
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Returns None when the file isn't parseable; callers skip + continue
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so one corrupt EML does not kill the whole INBOX listing. ``uid``
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is assigned by the caller after concatenation.
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"""
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try:
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raw = path.read_bytes()
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msg = email.message_from_bytes(raw, policy=email.policy.compat32)
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except Exception: # noqa: BLE001
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return None
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from_name, from_addr = _split_addr(msg.get("From", ""))
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_to_name, to_addr = _split_addr(msg.get("To", ""))
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subject = (msg.get("Subject") or "").strip()
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date = msg.get("Date") or ""
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return {
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"uid": 0,
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"flags": [], # never \Seen for spool emails — fresh delivery
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"from_name": from_name or (from_addr.split("@", 1)[0] if from_addr else "Unknown"),
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"from_addr": from_addr or "unknown@localhost",
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"to_addr": to_addr or "unknown@localhost",
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"subject": subject or "(no subject)",
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"date": date,
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"body": raw.decode("utf-8", errors="replace"),
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}
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def _seed_dict_to_entry(entry: dict) -> dict | None:
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"""Validate and normalize a JSON-supplied dict into the bait shape.
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Required keys: from_addr, to_addr, subject, body. Optional: date,
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from_name, flags. Bad rows return None (caller skips + logs).
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"""
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if not isinstance(entry, dict):
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return None
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for key in _SEED_JSON_REQUIRED:
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if not isinstance(entry.get(key), str) or not entry[key]:
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return None
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from_addr = entry["from_addr"]
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from_name = str(entry.get("from_name") or from_addr.split("@", 1)[0])
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date = str(entry.get("date") or "")
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flags = entry.get("flags") or []
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if not isinstance(flags, list):
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flags = []
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body = entry["body"]
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# If body is a bare string (no headers), wrap it into RFC 822 so
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# IMAP BODY[]/RFC822 fetches return a complete message — matches
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# the hardcoded _BAIT_EMAILS shape.
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if "\r\n\r\n" not in body and "\n\n" not in body:
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headers = (
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f"Date: {date}\r\n"
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f"From: {from_name} <{from_addr}>\r\n"
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f"To: {entry['to_addr']}\r\n"
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f"Subject: {entry['subject']}\r\n"
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"\r\n"
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)
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body = headers + body
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return {
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"uid": 0,
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"flags": list(flags),
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"from_name": from_name,
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"from_addr": from_addr,
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"to_addr": entry["to_addr"],
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"subject": entry["subject"],
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"date": date,
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"body": body,
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}
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def _load_seed_json(path: Path) -> list[dict]:
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"""Load a JSON list of dicts into entries. Bad rows logged + skipped."""
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try:
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raw = path.read_text(encoding="utf-8")
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data = json.loads(raw)
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except (OSError, ValueError) as exc:
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print(f"imap: seed json {path} unreadable: {exc}", file=sys.stderr)
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return []
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if not isinstance(data, list):
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print(f"imap: seed json {path} must be a list", file=sys.stderr)
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return []
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out: list[dict] = []
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for i, entry in enumerate(data):
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normalized = _seed_dict_to_entry(entry)
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if normalized is None:
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print(f"imap: seed json {path}[{i}] missing required keys", file=sys.stderr)
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continue
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out.append(normalized)
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return out
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def _scan_seed(path: Path) -> list[dict]:
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"""Resolve *path* into seed entries.
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- Directory: rglob ``*.eml`` (mtime-sorted) + every ``*.json`` (each
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a list of dicts).
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- File ending in ``.json``: that JSON list.
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- File ending in ``.eml``: that single EML.
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"""
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out: list[dict] = []
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try:
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if path.is_dir():
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eml_paths = sorted(
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(p for p in path.rglob("*.eml") if p.is_file()),
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key=lambda p: p.stat().st_mtime,
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)
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for p in eml_paths:
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d = _eml_to_dict(p)
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if d is not None:
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out.append(d)
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for jp in sorted(p for p in path.rglob("*.json") if p.is_file()):
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out.extend(_load_seed_json(jp))
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elif path.suffix.lower() == ".json" and path.is_file():
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out.extend(_load_seed_json(path))
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elif path.suffix.lower() == ".eml" and path.is_file():
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d = _eml_to_dict(path)
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if d is not None:
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out.append(d)
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except OSError:
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return []
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return out
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def _get_emails() -> list[dict]:
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"""Return the active mailbox list: ``_BAIT_EMAILS`` concatenated
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with seed entries (directory of .eml/.json or a single .json/.eml).
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UIDs are renumbered sequentially across the combined list so the
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hardcoded baits keep their original UIDs (1..10) and seeded entries
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pick up from len(_BAIT_EMAILS)+1.
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"""
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global _seed_cache, _seed_cache_path_mtime, _seed_cache_loaded_at
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if not _EMAIL_SEED_PATH:
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return _BAIT_EMAILS
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||
seed_path = Path(_EMAIL_SEED_PATH)
|
||
try:
|
||
path_stat = seed_path.stat()
|
||
except OSError:
|
||
return _BAIT_EMAILS
|
||
|
||
now = time.monotonic()
|
||
fresh_enough = (
|
||
_seed_cache is not None
|
||
and (now - _seed_cache_loaded_at) < _SEED_RESCAN_INTERVAL
|
||
and path_stat.st_mtime == _seed_cache_path_mtime
|
||
)
|
||
if fresh_enough:
|
||
seed = _seed_cache or []
|
||
else:
|
||
seed = _scan_seed(seed_path)
|
||
_seed_cache = seed
|
||
_seed_cache_path_mtime = path_stat.st_mtime
|
||
_seed_cache_loaded_at = now
|
||
|
||
if not seed:
|
||
return _BAIT_EMAILS
|
||
|
||
combined: list[dict] = list(_BAIT_EMAILS)
|
||
base_uid = len(_BAIT_EMAILS)
|
||
for i, entry in enumerate(seed, start=1):
|
||
renumbered = dict(entry)
|
||
renumbered["uid"] = base_uid + i
|
||
combined.append(renumbered)
|
||
return combined
|
||
|
||
|
||
# ── Logging ───────────────────────────────────────────────────────────────────
|
||
|
||
def _log(event_type: str, severity: int = 6, **kwargs) -> None:
|
||
line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
|
||
write_syslog_file(line)
|
||
forward_syslog(line, LOG_TARGET)
|
||
|
||
# ── FETCH helpers ─────────────────────────────────────────────────────────────
|
||
|
||
def _parse_seq_range(range_str: str, total: int) -> list[int]:
|
||
"""Parse IMAP sequence set ('1', '1:3', '1:*', '*') → list of 1-based indices."""
|
||
result: list[int] = []
|
||
for part in range_str.split(","):
|
||
part = part.strip()
|
||
if ":" in part:
|
||
lo_s, hi_s = part.split(":", 1)
|
||
lo = total if lo_s == "*" else int(lo_s)
|
||
hi = total if hi_s == "*" else int(hi_s)
|
||
result.extend(range(min(lo, hi), max(lo, hi) + 1))
|
||
elif part == "*":
|
||
result.append(total)
|
||
else:
|
||
result.append(int(part))
|
||
return [n for n in result if 1 <= n <= total]
|
||
|
||
|
||
def _parse_fetch_items(items_str: str) -> list[str]:
|
||
"""Parse '(FLAGS ENVELOPE)' or 'BODY[]' → list of item name strings."""
|
||
s = items_str.strip()
|
||
if s.startswith("(") and s.endswith(")"):
|
||
s = s[1:-1]
|
||
tokens, i = [], 0
|
||
while i < len(s):
|
||
if s[i] == " ":
|
||
i += 1
|
||
continue
|
||
j, depth = i, 0
|
||
while j < len(s):
|
||
if s[j] == "[":
|
||
depth += 1
|
||
elif s[j] == "]":
|
||
depth -= 1
|
||
elif s[j] == " " and depth == 0:
|
||
break
|
||
j += 1
|
||
tokens.append(s[i:j].upper())
|
||
i = j
|
||
return tokens
|
||
|
||
|
||
def _envelope(msg: dict) -> str:
|
||
"""Build minimal RFC 3501 ENVELOPE tuple string."""
|
||
def addr(name: str, email: str) -> str:
|
||
parts = email.split("@", 1)
|
||
user = parts[0]
|
||
host = parts[1] if len(parts) > 1 else ""
|
||
safe_name = name.replace('"', '\\"')
|
||
return f'("{safe_name}" NIL "{user}" "{host}")'
|
||
|
||
from_addr = addr(msg["from_name"], msg["from_addr"])
|
||
to_addr = addr("", msg["to_addr"])
|
||
subject = msg["subject"].replace('"', '\\"')
|
||
return (
|
||
f'("{msg["date"]}" "{subject}" '
|
||
f'({from_addr}) ({from_addr}) ({from_addr}) '
|
||
f'({to_addr}) NIL NIL NIL "<{msg["uid"]}@{NODE_NAME}>")'
|
||
)
|
||
|
||
|
||
def _build_fetch_response(seq: int, msg: dict, items: list[str]) -> bytes:
|
||
"""Build the bytes for a single '* N FETCH (...)' response."""
|
||
non_literal: list[str] = []
|
||
literal_name: str | None = None
|
||
literal_raw: bytes | None = None
|
||
|
||
for item in items:
|
||
norm = item.upper()
|
||
if norm == "FLAGS":
|
||
flags = " ".join(msg["flags"]) if msg["flags"] else ""
|
||
non_literal.append(f"FLAGS ({flags})")
|
||
elif norm == "ENVELOPE":
|
||
non_literal.append(f"ENVELOPE {_envelope(msg)}")
|
||
elif norm == "RFC822.SIZE":
|
||
non_literal.append(f"RFC822.SIZE {len(msg['body'].encode())}")
|
||
elif norm in ("UID",):
|
||
non_literal.append(f"UID {msg['uid']}")
|
||
elif norm in ("BODY[]", "RFC822", "BODY[TEXT]", "BODY.PEEK[]"):
|
||
literal_name = "BODY[]"
|
||
literal_raw = msg["body"].encode()
|
||
elif norm in ("BODY[HEADER]", "BODY.PEEK[HEADER]"):
|
||
header_part = msg["body"].split("\r\n\r\n", 1)[0] + "\r\n\r\n"
|
||
literal_name = "BODY[HEADER]"
|
||
literal_raw = header_part.encode()
|
||
# unknown items silently ignored
|
||
|
||
if literal_raw is not None:
|
||
prefix_str = (" ".join(non_literal) + " ") if non_literal else ""
|
||
header = f"* {seq} FETCH ({prefix_str}{literal_name} {{{len(literal_raw)}}}\r\n".encode()
|
||
return header + literal_raw + b")\r\n"
|
||
else:
|
||
return f"* {seq} FETCH ({' '.join(non_literal)})\r\n".encode()
|
||
|
||
|
||
# ── Protocol ──────────────────────────────────────────────────────────────────
|
||
|
||
class IMAPProtocol(asyncio.Protocol):
|
||
_transport: asyncio.Transport | None = None
|
||
_peer: tuple[str, int]
|
||
|
||
def __init__(self):
|
||
self._transport = None
|
||
self._peer = ("?", 0)
|
||
self._buf = b""
|
||
self._state = "NOT_AUTHENTICATED"
|
||
self._selected = None # mailbox name currently selected
|
||
|
||
def connection_made(self, transport: asyncio.BaseTransport) -> None:
|
||
self._transport = cast(asyncio.Transport, transport)
|
||
self._peer = self._transport.get_extra_info("peername", ("?", 0))
|
||
_log("connect", src=self._peer[0], src_port=self._peer[1])
|
||
banner = IMAP_BANNER if IMAP_BANNER.endswith("\r\n") else IMAP_BANNER + "\r\n"
|
||
self._transport.write(banner.encode())
|
||
|
||
def data_received(self, data):
|
||
self._buf += data
|
||
while b"\n" in self._buf:
|
||
line, self._buf = self._buf.split(b"\n", 1)
|
||
self._handle_line(line.decode(errors="replace").strip())
|
||
|
||
def connection_lost(self, exc):
|
||
_log("disconnect", src=self._peer[0] if self._peer else "?")
|
||
|
||
# ── Command dispatch ──────────────────────────────────────────────────────
|
||
|
||
def _handle_line(self, line: str) -> None:
|
||
parts = line.split(None, 2)
|
||
if not parts:
|
||
return
|
||
tag = parts[0]
|
||
cmd = parts[1].upper() if len(parts) > 1 else ""
|
||
args = parts[2] if len(parts) > 2 else ""
|
||
|
||
_log("command", src=self._peer[0], cmd=cmd, state=self._state)
|
||
|
||
# Commands valid in any state
|
||
if cmd == "CAPABILITY":
|
||
self._w(b"* CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS"
|
||
b" ID ENABLE IDLE AUTH=PLAIN AUTH=LOGIN\r\n")
|
||
self._w(f"{tag} OK CAPABILITY completed\r\n")
|
||
|
||
elif cmd == "NOOP":
|
||
self._w(f"{tag} OK\r\n")
|
||
|
||
elif cmd == "LOGOUT":
|
||
self._w(b"* BYE Logging out\r\n")
|
||
self._w(f"{tag} OK LOGOUT completed\r\n")
|
||
assert self._transport is not None
|
||
self._transport.close()
|
||
|
||
# NOT_AUTHENTICATED only
|
||
elif cmd == "LOGIN":
|
||
self._cmd_login(tag, args)
|
||
|
||
# AUTHENTICATED or SELECTED
|
||
elif cmd in ("LIST", "LSUB"):
|
||
self._cmd_list(tag, cmd)
|
||
elif cmd == "STATUS":
|
||
self._cmd_status(tag, args)
|
||
elif cmd in ("SELECT", "EXAMINE"):
|
||
self._cmd_select(tag, cmd, args)
|
||
|
||
# SELECTED only
|
||
elif cmd == "FETCH":
|
||
self._cmd_fetch(tag, args, use_uid=False)
|
||
elif cmd == "SEARCH":
|
||
self._cmd_search(tag)
|
||
elif cmd == "CLOSE":
|
||
self._cmd_close(tag)
|
||
|
||
# UID prefix — dispatch sub-command
|
||
elif cmd == "UID":
|
||
sub_parts = args.split(None, 1)
|
||
sub_cmd = sub_parts[0].upper() if sub_parts else ""
|
||
sub_args = sub_parts[1] if len(sub_parts) > 1 else ""
|
||
if sub_cmd == "FETCH":
|
||
self._cmd_fetch(tag, sub_args, use_uid=True)
|
||
elif sub_cmd == "SEARCH":
|
||
self._cmd_search(tag, _uid_mode=True)
|
||
else:
|
||
self._w(f"{tag} BAD Unknown UID sub-command\r\n")
|
||
|
||
else:
|
||
self._w(f"{tag} BAD Command not recognized or not supported\r\n")
|
||
|
||
# ── Command implementations ───────────────────────────────────────────────
|
||
|
||
def _cmd_login(self, tag: str, args: str) -> None:
|
||
if self._state != "NOT_AUTHENTICATED":
|
||
self._w(f"{tag} BAD Already authenticated\r\n")
|
||
return
|
||
parts = args.split(None, 1)
|
||
username = parts[0].strip('"') if parts else ""
|
||
password = parts[1].strip('"') if len(parts) > 1 else ""
|
||
_enc = encode_secret(password)
|
||
if VALID_USERS.get(username) == password:
|
||
self._state = "AUTHENTICATED"
|
||
_log("auth", src=self._peer[0], username=username, principal=username,
|
||
outcome="success", **_enc)
|
||
self._w(f"{tag} OK [CAPABILITY IMAP4rev1] Logged in\r\n")
|
||
else:
|
||
_log("auth", src=self._peer[0], username=username, principal=username,
|
||
outcome="failure", severity=SEVERITY_WARNING, **_enc)
|
||
self._w(f"{tag} NO [AUTHENTICATIONFAILED] Authentication failed.\r\n")
|
||
|
||
def _cmd_list(self, tag: str, cmd: str) -> None:
|
||
if self._state == "NOT_AUTHENTICATED":
|
||
self._w(f"{tag} BAD Not authenticated\r\n")
|
||
return
|
||
for box in _MAILBOXES:
|
||
self._w(f'* {cmd} (\\HasNoChildren) "/" "{box}"\r\n')
|
||
self._w(f"{tag} OK {cmd} completed\r\n")
|
||
|
||
def _cmd_status(self, tag: str, args: str) -> None:
|
||
if self._state == "NOT_AUTHENTICATED":
|
||
self._w(f"{tag} BAD Not authenticated\r\n")
|
||
return
|
||
parts = args.split(None, 1)
|
||
mailbox = parts[0].strip('"') if parts else "INBOX"
|
||
attr_str = parts[1].strip("()").upper() if len(parts) > 1 else "MESSAGES"
|
||
|
||
n = len(_get_emails()) if mailbox == "INBOX" else 0
|
||
counts = {"MESSAGES": n, "RECENT": 0, "UNSEEN": n} if mailbox == "INBOX" \
|
||
else {"MESSAGES": 0, "RECENT": 0, "UNSEEN": 0}
|
||
|
||
result_parts = []
|
||
for attr in attr_str.split():
|
||
if attr in counts:
|
||
result_parts.append(f"{attr} {counts[attr]}")
|
||
self._w(f"* STATUS {mailbox} ({' '.join(result_parts)})\r\n")
|
||
self._w(f"{tag} OK STATUS completed\r\n")
|
||
|
||
def _cmd_select(self, tag: str, cmd: str, args: str) -> None:
|
||
if self._state == "NOT_AUTHENTICATED":
|
||
self._w(f"{tag} BAD Not authenticated\r\n")
|
||
return
|
||
mailbox = args.strip('"')
|
||
emails = _get_emails()
|
||
total = len(emails) if mailbox == "INBOX" else 0
|
||
self._selected = mailbox
|
||
self._state = "SELECTED"
|
||
self._w(f"* {total} EXISTS\r\n")
|
||
self._w(b"* 0 RECENT\r\n")
|
||
self._w(b"* OK [UNSEEN 1] Message 1 is first unseen\r\n")
|
||
self._w(b"* OK [UIDVALIDITY 1712345678] UIDs valid\r\n")
|
||
self._w(f"* OK [UIDNEXT {total + 1}] Predicted next UID\r\n")
|
||
self._w(b"* FLAGS (\\Answered \\Flagged \\Deleted \\Seen \\Draft)\r\n")
|
||
self._w(b"* OK [PERMANENTFLAGS (\\Deleted \\Seen \\*)] Limited\r\n")
|
||
mode = "READ-ONLY" if cmd == "EXAMINE" else "READ-WRITE"
|
||
self._w(f"{tag} OK [{mode}] {cmd} completed\r\n")
|
||
|
||
def _cmd_fetch(self, tag: str, args: str, use_uid: bool) -> None:
|
||
if self._state != "SELECTED":
|
||
self._w(f"{tag} BAD Not in selected state\r\n")
|
||
return
|
||
parts = args.split(None, 1)
|
||
range_str = parts[0] if parts else "1:*"
|
||
items_str = parts[1] if len(parts) > 1 else "FLAGS"
|
||
|
||
emails = _get_emails()
|
||
total = len(emails)
|
||
indices = _parse_seq_range(range_str, total)
|
||
items = _parse_fetch_items(items_str)
|
||
# Ensure UID is included when using UID FETCH
|
||
if use_uid and "UID" not in items:
|
||
items = ["UID"] + items
|
||
|
||
assert self._transport is not None
|
||
for seq in indices:
|
||
if 1 <= seq <= total:
|
||
self._transport.write(_build_fetch_response(seq, emails[seq - 1], items))
|
||
self._w(f"{tag} OK FETCH completed\r\n")
|
||
|
||
def _cmd_search(self, tag: str, _uid_mode: bool = False) -> None:
|
||
if self._state != "SELECTED":
|
||
self._w(f"{tag} BAD Not in selected state\r\n")
|
||
return
|
||
nums = " ".join(str(i) for i in range(1, len(_get_emails()) + 1))
|
||
self._w(f"* SEARCH {nums}\r\n")
|
||
self._w(f"{tag} OK SEARCH completed\r\n")
|
||
|
||
def _cmd_close(self, tag: str) -> None:
|
||
if self._state != "SELECTED":
|
||
self._w(f"{tag} BAD Not in selected state\r\n")
|
||
return
|
||
self._state = "AUTHENTICATED"
|
||
self._selected = None
|
||
self._w(f"{tag} OK CLOSE completed\r\n")
|
||
|
||
# ── Helpers ───────────────────────────────────────────────────────────────
|
||
|
||
def _w(self, data: str | bytes) -> None:
|
||
assert self._transport is not None
|
||
if isinstance(data, str):
|
||
data = data.encode()
|
||
self._transport.write(data)
|
||
|
||
|
||
async def main():
|
||
_log("startup", msg=f"IMAP server starting as {NODE_NAME}")
|
||
loop = asyncio.get_running_loop()
|
||
server = await loop.create_server(IMAPProtocol, "0.0.0.0", PORT) # nosec B104
|
||
async with server:
|
||
await server.serve_forever()
|
||
|
||
|
||
if __name__ == "__main__":
|
||
asyncio.run(main())
|