1 files changed, 349 insertions, 0 deletions
diff --git a/script/qmauth.py b/script/qmauth.py
new file mode 100755
index 0000000..7803483
--- /dev/null
+++ b/script/qmauth.py
@@ -0,0 +1,349 @@
+#!/usr/bin/env python3
+
+"""qmauth.py
+
+Extract delivers information about emails from a maildir.
+Runs with elevated privileges.
+
+This program is started by qmail-authuser with elevated privileges after
+a successful login.
+Input directives are provided as command line arguments.
+Output is delivered via STDOUT as json and log information via STDERR.
+
+Exit codes::
+
+      1  reserved
+      2  reserved
+      3  operational error       (error message in output)
+      4  user error              (no output)
+      5  issue switching to user (no output)
+    110  reserved
+    111  reserved
+"""
+
+import json
+import logging
+import re
+
+from argparse  import ArgumentParser
+from datetime  import datetime
+from email     import message_from_binary_file, policy
+from functools import cache
+from glob      import glob
+from mailbox   import Maildir, MaildirMessage
+from os        import environ, getpid, path, setuid, stat
+from pathlib   import Path
+from pwd       import getpwnam
+from sys       import exit as sysexit, stdout
+
+
+class MyMaildir(Maildir):
+
+    def __init__(self, dirname, *args, **kwargs):
+        self.__path = dirname
+        super().__init__(dirname, *args, **kwargs)
+
+    def get_filename(self, mid):
+        if mid not in self:
+            raise KeyError(mid)
+        p_cur = glob(path.join(self.__path, 'cur', mid + '*'))
+        p_new = glob(path.join(self.__path, 'new', mid + '*'))
+        res = p_cur + p_new
+        if len(res) != 1:
+            raise LookupError("could not uniquely identify file for mail-id")
+        return res[0]
+
+    def get_folder(self, folder):
+        # copy from internal implementation
+        return MyMaildir(
+            path.join(self._path, '.' + folder), factory=self._factory, create=False,
+        )
+
+
+@cache
+def _file_size(fname):
+    return stat(fname).st_size
+
+
+def _adr(addrs):
+    if addrs is None:
+        return None
+    return [
+        {'address': addr.addr_spec, 'display_name': addr.display_name}
+        for addr in addrs.addresses
+    ]
+
+
+def _get_rcv_time(mid):
+    idx = mid.find('.')
+    assert idx >= 0
+    return float(mid[:idx])
+
+
+def startup(maildir, su, user):
+
+    del environ['PATH']
+
+    netfehcom_uid = getpwnam(su).pw_uid
+    assert netfehcom_uid, "must be non root"
+    try:
+        setuid(netfehcom_uid)
+    except OSError:
+        logging.exception("error setting uid")
+        sysexit(5)
+
+    return MyMaildir(
+        maildir / user,
+        create=False,
+        factory=lambda x: MaildirMessage(
+            message_from_binary_file(x, policy=policy.default)
+        ),
+    )
+
+
+def _sort_by_sender(midmsg):
+    _, msg = midmsg
+
+    if len(addrs := msg['from'].addresses) == 1:
+        return addrs[0].addr_spec
+    else:
+        return msg['sender'].address.addr_spec
+
+
+def _sort_mails(f, sort):
+
+    reverse = False
+    if sort.startswith('!'):
+        reverse = True
+        sort = sort[1:]
+
+    by_rec_date = lambda midmsg: float(re.match(r"\d+\.\d+", midmsg[0], re.ASCII)[0])
+
+    if   sort == 'date':    keyfn = by_rec_date
+    elif sort == 'sender':  keyfn = _sort_by_sender
+    elif sort == 'subject': keyfn = lambda midmsg: midmsg[1]['subject']
+    elif sort == 'size':    keyfn = lambda midmsg: _file_size(f.get_filename(midmsg[0]))
+    elif sort == '':        keyfn = by_rec_date
+    else:
+        logging.warning("unknown sort-verb %r", sort)
+        reverse = False
+        keyfn = by_rec_date
+
+    return keyfn, reverse
+
+
+def _get_mime_head_info(msg):
+    return {
+        'content_maintype':    msg.get_content_maintype(),
+        'content_subtype':     msg.get_content_subtype(),
+        'content_disposition': msg.get_content_disposition(),
+        'filename':            msg.get_filename(),
+    }
+
+
+def _get_head_info(msg):
+    return {
+        'date': msg['date'].datetime.isoformat(),
+
+        'from':     _adr(msg['from']),
+        'sender':   _adr(msg['sender']),
+        'reply_to': _adr(msg['reply-to']),
+
+        'to':  _adr(msg['to']),
+        'cc':  _adr(msg['cc']),
+        'bcc': _adr(msg['bcc']),
+
+        'subject':  msg['subject'],
+        'comments': msg['comments'],
+        'keywords': msg['keywords'],
+
+        'mime': _get_mime_head_info(msg),
+    }
+
+
+def list_mails(f, start, end, sortby, folder):
+
+    assert 0 <= start <= end
+
+    if folder:
+        f = f.get_folder(folder)
+
+    if start == end:
+        return []
+
+    kfn, reverse = _sort_mails(f, sortby)
+    msgs = list(f.items())
+    msgs.sort(key=kfn, reverse=reverse)
+    msgs = msgs[start : min(len(msgs), end)]
+
+    return [
+        {
+            'message_handle': mid,
+            'byte_size':      _file_size(f.get_filename(mid)),
+            'unread':         'S' in msg.get_flags(),
+            'date_received':  datetime.fromtimestamp(_get_rcv_time(mid)).isoformat(),
+            'head':           _get_head_info(msg),
+        }
+        for mid, msg in msgs
+    ]
+
+
+def count_mails(f, subfolder):
+    if subfolder:
+        f = f.get_folder(subfolder)
+
+    return {
+        'total_mails':  len(f),
+        'byte_size':    sum(_file_size(f.get_filename(mid)) for mid in f.keys()),
+        'unread_mails': len([1 for m in f if 'S' in m.get_flags()]),
+    }
+
+
+def _get_body(mail):
+    if not mail.is_multipart():
+        if mail.get_content_maintype() == 'text':
+            return mail.get_payload(decode=True).decode()
+        else:
+            return mail.get_payload()
+
+    if (mctype := mail.get_content_maintype()) == 'message':
+        mm = mail.get_payload()
+        assert len(mm) == 1
+        msg = mm[0]
+        return {
+            'head': _get_head_info(msg),
+            'body': msg.get_content(),
+        }
+    elif mctype == 'multipart':
+        return {
+            'preamble': mail.preamble,
+            'parts': [
+                {
+                    'head': _get_mime_head_info(part),
+                    'body': _get_body(part),
+                }
+                for part in mail.get_payload()
+            ],
+            'epilogue': mail.epilogue,
+        }
+    else:
+        raise ValueError(f"unknown major content-type {mctype!r}")
+
+
+def read_mail(f, subfolder, mid):
+    if subfolder:
+        f = f.get_folder(subfolder)
+
+    msg = f[mid]
+    if not msg:
+        return {'error': "no such message", 'mid': mid}
+
+    return {
+        'head': _get_head_info(msg),
+        'body': _get_body(msg),
+    }
+
+
+def _matches(m, pattern):
+    if m.is_multipart():
+        return any(
+            1
+            for part in m.body.parts
+            if re.search(pattern, part.decoded()) or re.search(pattern, part.subject)
+        )
+    return re.search(pattern, m.body.decoded()) or re.search(pattern, m.subject)
+
+
+def search_mails(f, pattern: str, subfolder: str):
+    if subfolder:
+        f = f.get_folder(subfolder)
+
+    return [
+        {
+            'head': _get_head_info(msg),
+            'body': _get_body(msg),
+        }
+        for msg in f.values()
+        if _matches(msg, pattern)
+    ]
+
+
+def folders(f):
+    return f.list_folders()
+
+
+def move_mail(f, mid, from_, to):
+    if from_:
+        f = f.get_folder(from_)
+
+    fname = Path(f.get_filename(mid))
+
+    assert to in f.list_folders()
+
+    sep = -2 if not from_ else -3
+
+    if to:
+        res = fname.parts[:sep] + ('.' + to,) + fname.parts[-2:]
+    else:
+        res = fname.parts[:sep] + fname.parts[-2:]
+
+    fname.rename(Path(*res))
+
+    return 1
+
+
+ap = ArgumentParser(allow_abbrev=False)
+ap.add_argument('maildir_path', type=Path)
+ap.add_argument('os_user')
+ap.add_argument('mail_user')
+sp = ap.add_subparsers(title='methods', required=True)
+
+sp_list = sp.add_parser('list')
+sp_list.add_argument('folder', metavar='subfolder')
+sp_list.add_argument('start', type=int)
+sp_list.add_argument('end', type=int)
+sp_list.add_argument('sortby', metavar='sort_by')
+sp_list.set_defaults(run=list_mails)
+
+sp_count = sp.add_parser('count')
+sp_count.add_argument('subfolder')
+sp_count.set_defaults(run=count_mails)
+
+sp_read = sp.add_parser('read')
+sp_read.add_argument('subfolder')
+sp_read.add_argument('mid', metavar='message')
+sp_read.set_defaults(run=read_mail)
+
+sp_folders = sp.add_parser('folders')
+sp_folders.set_defaults(run=folders)
+
+sp_move = sp.add_parser('move')
+sp_move.add_argument('mid', metavar='message')
+sp_move.add_argument('from_', metavar='from')
+sp_move.add_argument('to')
+sp_move.set_defaults(run=move_mail)
+
+sp_search = sp.add_parser('search')
+sp_search.add_argument('pattern')
+sp_search.add_argument('subfolder')
+sp_search.set_defaults(run=search_mails)
+
+
+if __name__ == '__main__':
+    try:
+        logging.basicConfig(
+            level='INFO',
+            format="%(levelname)s:"+str(getpid())+":%(message)s",
+        )
+        args = vars(ap.parse_args())
+        logging.debug("started with %s", args)
+        s = startup(args.pop('maildir_path'), args.pop('os_user'), args.pop('mail_user'))
+        logging.debug("setuid successful")
+        run = args.pop('run')
+        reply = run(s, **args)
+        json.dump(reply, stdout)
+        if isinstance(reply, dict) and 'error' in reply:
+            sysexit(3)
+    except Exception:
+        logging.exception("qmauth.py error")
+        sysexit(4)