the imap & smtp servers now allow logging in with tls client authentication and
the "external" sasl authentication mechanism. email clients like thunderbird,
fairemail, k9, macos mail implement it. this seems to be the most secure among
the authentication mechanism commonly implemented by clients. a useful property
is that an account can have a separate tls public key for each device/email
client. with tls client cert auth, authentication is also bound to the tls
connection. a mitm cannot pass the credentials on to another tls connection,
similar to scram-*-plus. though part of scram-*-plus is that clients verify
that the server knows the client credentials.
for tls client auth with imap, we send a "preauth" untagged message by default.
that puts the connection in authenticated state. given the imap connection
state machine, further authentication commands are not allowed. some clients
don't recognize the preauth message, and try to authenticate anyway, which
fails. a tls public key has a config option to disable preauth, keeping new
connections in unauthenticated state, to work with such email clients.
for smtp (submission), we don't require an explicit auth command.
both for imap and smtp, we allow a client to authenticate with another
mechanism than "external". in that case, credentials are verified, and have to
be for the same account as the tls client auth, but the adress can be another
one than the login address configured with the tls public key.
only the public key is used to identify the account that is authenticating. we
ignore the rest of the certificate. expiration dates, names, constraints, etc
are not verified. no certificate authorities are involved.
users can upload their own (minimal) certificate. the account web interface
shows openssl commands you can run to generate a private key, minimal cert, and
a p12 file (the format that email clients seem to like...) containing both
private key and certificate.
the imapclient & smtpclient packages can now also use tls client auth. and so
does "mox sendmail", either with a pem file with private key and certificate,
or with just an ed25519 private key.
there are new subcommands "mox config tlspubkey ..." for
adding/removing/listing tls public keys from the cli, by the admin.
needed for upcoming changes, where (now) package admin needs to import package
store. before, because package store imports mox- (for accessing the active
config), that would lead to a cyclic import. package mox- keeps its active
config, package admin has the higher-level config-changing functions.
if files {webmail,webaccount,webadmin}.{css,js} exist in the configdir (where
the mox.conf file lives), their contents are included in the web apps.
the webmail now uses css variables, mostly for colors. so you can write a
custom webmail.css that changes the variables, e.g.:
:root {
--color: blue
}
you can also look at css class names and override their styles.
in the future, we may want to make some css variables configurable in the
per-user settings in the webmail. should reduce the number of variables first.
any custom javascript is loaded first. if it defines a global function
"moxBeforeDisplay", that is called each time a page loads (after
authentication) with the DOM element of the page content as parameter. the
webmail is a single persistent page. this can be used to make some changes to
the DOM, e.g. inserting some elements. we'll have to see how well this works in
practice. perhaps some patterns emerge (e.g. adding a logo), and we can make
those use-cases easier to achieve.
helps partially with issue #114, and based on questions from laura-lilly on
matrix.
since ios18, downloaded files don't go immediately to the settings (which is
somewhat understandable given potential for abuse), but go to the Files app.
opening them in the Files app then adds them to the settings where they can be
installed.
this is a typical case if you made an alias to test how it works, with your
account. we may have to make this behaviour optional in the future.
for issue #220 by wneessen, thanks for reporting!
before, we would just say "session expired". now we say "session expired (after
12 hours inactivity)" (for admin) or "session expired (after 24 hours
inactivity)" for account/webmail. for unknown sessions in the admin interface,
we also explain that server restarts and 10 more new sessions can be the
reason.
for issue #202 by ally9335
for issue #186 by morki, thanks for reporting and providing sample favicons.
generated by the mentioned generator at favicon.io, with the ubuntu font and a
fuchsia-like color.
the favicon is served for listeners/domains that have the
admin/account/webmail/webapi endpoints enabled, i.e. user-facing. the mta-sts,
autoconfig, etc urls don't serve the favicon.
admins can create webhandler routes to serve another favicon. these webhandler
routes are evaluted before the favicon route (a "service handler").
per listener, you could enable the admin/account/webmail/webapi handlers. but
that would serve those services on their configured paths (/admin/, /,
/webmail/, /webapi/) on all domains mox would be webserving, including any
non-mail domains. so your www.example/admin/ would be serving the admin web
interface, with no way to disabled that.
with this change, the admin interface is only served on requests to (based on
Host header):
- ip addresses
- the listener host name (explicitly configured in the listener, with fallback
to global hostname)
- "localhost" (for ssh tunnel/forwarding scenario's)
the account/webmail/webapi interfaces are served on the same domains as the
admin interface, and additionally:
- the client settings domains, as optionally configured in each Domain in
domains.conf. typically "mail.<yourdomain>".
this means the internal services are no longer served on other domains
configured in the webserver, e.g. www.example.org/admin/ will not be handled
specially.
the order of evaluation of routes/services is also changed:
before this change, the internal handlers would always be evaluated first.
with this change, only the system handlers for
MTA-STS/autoconfig/ACME-validation will be evaluated first. then the webserver
handlers. and finally the internal services (admin/account/webmail/webapi).
this allows an admin to configure overrides for some of the domains (per
hostname-matching rules explained above) that would normally serve these
services.
webserver handlers can now be configured that pass the request to an internal
service: in addition to the existing static/redirect/forward config options,
there is now an "internal" config option, naming the service
(admin/account/webmail/webapi) for handling the request. this allows enabling
the internal services on custom domains.
for issue #160 by TragicLifeHu, thanks for reporting!
it's the responsibility of the sender to use unique fromid's.
we do check if that's the case, and return an error if not.
also make it more clear that "unique smtp mail from addresses" map to the
"FromIDLoginAddresses" account config field.
based on feedback from cuu508 for #31, thanks!
since email addresses can contain multiple consecutive spaces.
this is a valid address: " "@localhost
and this is a different valid address: " "@localhost
webmail still todo
the members must currently all be addresses of local accounts.
a message sent to an alias is accepted if at least one of the members accepts
it. if no members accepts it (e.g. due to bad reputation of sender), the
message is rejected.
if a message is submitted to both an alias addresses and to recipients that are
members of the alias in an smtp transaction, the message will be delivered to
such members only once. the same applies if the address in the message
from-header is the address of a member: that member won't receive the message
(they sent it). this prevents duplicate messages.
aliases have three configuration options:
- PostPublic: whether anyone can send through the alias, or only members.
members-only lists can be useful inside organizations for internal
communication. public lists can be useful for support addresses.
- ListMembers: whether members can see the addresses of other members. this can
be seen in the account web interface. in the future, we could export this in
other ways, so clients can expand the list.
- AllowMsgFrom: whether messages can be sent through the alias with the alias
address used in the message from-header. the webmail knows it can use that
address, and will use it as from-address when replying to a message sent to
that address.
ideas for the future:
- allow external addresses as members. still with some restrictions, such as
requiring a valid dkim-signature so delivery has a chance to succeed. will
also need configuration of an admin that can receive any bounces.
- allow specifying specific members who can sent through the list (instead of
all members).
for github issue #57 by hmfaysal.
also relevant for #99 by naturalethic.
thanks to damir & marin from sartura for discussing requirements/features.
per mailbox, or for all mailboxes, in maildir/mbox format, in tar/tgz/zip
archive or without archive format for single mbox, single or recursive. the
webaccount already had an option to export all mailboxes, it now looks similar
to the webmail version.
if the message has a list-id header, we assume this is a (mailing) list
message, and we require a dkim/spf-verified domain (we prefer the shortest that
is a suffix of the list-id value). the rule we would add will mark such
messages as from a mailing list, changing filtering rules on incoming messages
(not enforcing dmarc policies). messages will be matched on list-id header and
will only match if they have the same dkim/spf-verified domain.
if the message doesn't have a list-id header, we'll ask to match based on
"message from" address.
we don't ask the user in several cases:
- if the destination/source mailbox is a special-use mailbox (e.g.
trash,archive,sent,junk; inbox isn't included)
- if the rule already exist (no point in adding it again).
- if the user said "no, not for this list-id/from-address" in the past.
- if the user said "no, not for messages moved to this mailbox" in the past.
we'll add the rule if the message was moved out of the inbox.
if the message was moved to the inbox, we check if there is a matching rule
that we can remove.
we now remember the "no" answers (for list-id, msg-from-addr and mailbox) in
the account database.
to implement the msgfrom rules, this adds support to rulesets for matching on
message "from" address. before, we could match on smtp from address (and other
fields). rulesets now also have a field for comments. webmail adds a note that
it created the rule, with the date.
manual editing of the rulesets is still in the webaccount page. this webmail
functionality is just a convenient way to add/remove common rules.
for applications to compose/send messages, receive delivery feedback, and
maintain suppression lists.
this is an alternative to applications using a library to compose messages,
submitting those messages using smtp, and monitoring a mailbox with imap for
DSNs, which can be processed into the equivalent of suppression lists. but you
need to know about all these standards/protocols and find libraries. by using
the webapi & webhooks, you just need a http & json library.
unfortunately, there is no standard for these kinds of api, so mox has made up
yet another one...
matching incoming DSNs about deliveries to original outgoing messages requires
keeping history of "retired" messages (delivered from the queue, either
successfully or failed). this can be enabled per account. history is also
useful for debugging deliveries. we now also keep history of each delivery
attempt, accessible while still in the queue, and kept when a message is
retired. the queue webadmin pages now also have pagination, to show potentially
large history.
a queue of webhook calls is now managed too. failures are retried similar to
message deliveries. webhooks can also be saved to the retired list after
completing. also configurable per account.
messages can be sent with a "unique smtp mail from" address. this can only be
used if the domain is configured with a localpart catchall separator such as
"+". when enabled, a queued message gets assigned a random "fromid", which is
added after the separator when sending. when DSNs are returned, they can be
related to previously sent messages based on this fromid. in the future, we can
implement matching on the "envid" used in the smtp dsn extension, or on the
"message-id" of the message. using a fromid can be triggered by authenticating
with a login email address that is configured as enabling fromid.
suppression lists are automatically managed per account. if a delivery attempt
results in certain smtp errors, the destination address is added to the
suppression list. future messages queued for that recipient will immediately
fail without a delivery attempt. suppression lists protect your mail server
reputation.
submitted messages can carry "extra" data through the queue and webhooks for
outgoing deliveries. through webapi as a json object, through smtp submission
as message headers of the form "x-mox-extra-<key>: value".
to make it easy to test webapi/webhooks locally, the "localserve" mode actually
puts messages in the queue. when it's time to deliver, it still won't do a full
delivery attempt, but just delivers to the sender account. unless the recipient
address has a special form, simulating a failure to deliver.
admins now have more control over the queue. "hold rules" can be added to mark
newly queued messages as "on hold", pausing delivery. rules can be about
certain sender or recipient domains/addresses, or apply to all messages pausing
the entire queue. also useful for (local) testing.
new config options have been introduced. they are editable through the admin
and/or account web interfaces.
the webapi http endpoints are enabled for newly generated configs with the
quickstart, and in localserve. existing configurations must explicitly enable
the webapi in mox.conf.
gopherwatch.org was created to dogfood this code. it initially used just the
compose/smtpclient/imapclient mox packages to send messages and process
delivery feedback. it will get a config option to use the mox webapi/webhooks
instead. the gopherwatch code to use webapi/webhook is smaller and simpler, and
developing that shaped development of the mox webapi/webhooks.
for issue #31 by cuu508
typescript now knows the full types, not just "any" for account config.
inline structs previously in config.Account are given their own type definition
so sherpa can generate types.
also update to latest sherpa lib that knows about time.Duration, to be used soon.
we include the username in session cookie values. but cookie values must be ascii-only, go's net/http's drops bad values. the typical solution is to querystring-encode/decode the cookie values, which we'll now do.
problem found by arnt, thanks for reporting!
- add option to put messages in the queue "on hold", preventing delivery
attempts until taken off hold again.
- add "hold rules", to automatically mark some/all submitted messages as "on
hold", e.g. from a specific account or to a specific domain.
- add operation to "fail" a message, causing a DSN to be delivered to the
sender. previously we could only drop a message from the queue.
- update admin page & add new cli tools for these operations, with new
filtering rules for selecting the messages to operate on. in the admin
interface, add filtering and checkboxes to select a set of messages to operate
on.
we only have a "storage" limit. for total disk usage. we don't have a limit on
messages (count) or mailboxes (count). also not on total annotation size, but
we don't have support annotations at all at the moment.
we don't implement setquota. with rfc 9208 that's allowed. with the previous
quota rfc 2087 it wasn't.
the status command can now return "DELETED-STORAGE". which should be the disk
space that can be reclaimed by removing messages with the \Deleted flags.
however, it's not very likely clients set the \Deleted flag without expunging
the message immediately. we don't want to go through all messages to calculate
the sum of message sizes with the deleted flag. we also don't currently track
that in MailboxCount. so we just respond with "0". not compliant, but let's
wait until someone complains.
when returning quota information, it is not possible to give the current usage
when no limit is configured. clients implementing rfc 9208 should probably
conclude from the presence of QUOTA=RES-* capabilities (only in rfc 9208, not
in 2087) and the absence of those limits in quota responses (or the absence of
an untagged quota response at all) that a resource type doesn't have a limit.
thunderbird will claim there is no quota information when no limit was
configured, so we can probably conclude that it implements rfc 2087, but not
rfc 9208.
we now also show the usage & limit on the account page.
for issue #115 by pmarini
preventing writing out a domains.conf that is invalid and can't be parsed
again. this happens when the last address was removed from an account. just a
click in the admin web interface.
accounts without email address cannot log in.
for issue #133 by ally9335
by explaining (in the titles/hovers) what the concepts and requirements are, by
using selects/dropdowns or datalist suggestions where we have a known list, by
automatically suggesting a good account name, and putting the input fields in a
more sensible order.
based on issue #132 by ally9335
both when parsing our configs, and for incoming on smtp or in messages.
so we properly compare things like é and e+accent as equal, and accept the
different encodings of that same address.
most content is in markdown files in website/, some is taken out of the repo
README and rfc/index.txt. a Go file generates html. static files are kept in a
separate repo due to size.
the http basic auth we had was very simple to reason about, and to implement.
but it has a major downside:
there is no way to logout, browsers keep sending credentials. ideally, browsers
themselves would show a button to stop sending credentials.
a related downside: the http auth mechanism doesn't indicate for which server
paths the credentials are.
another downside: the original password is sent to the server with each
request. though sending original passwords to web servers seems to be
considered normal.
our new approach uses session cookies, along with csrf values when we can. the
sessions are server-side managed, automatically extended on each use. this
makes it easy to invalidate sessions and keeps the frontend simpler (than with
long- vs short-term sessions and refreshing). the cookies are httponly,
samesite=strict, scoped to the path of the web interface. cookies are set
"secure" when set over https. the cookie is set by a successful call to Login.
a call to Logout invalidates a session. changing a password invalidates all
sessions for a user, but keeps the session with which the password was changed
alive. the csrf value is also random, and associated with the session cookie.
the csrf must be sent as header for api calls, or as parameter for direct form
posts (where we cannot set a custom header). rest-like calls made directly by
the browser, e.g. for images, don't have a csrf protection. the csrf value is
returned by the Login api call and stored in localstorage.
api calls without credentials return code "user:noAuth", and with bad
credentials return "user:badAuth". the api client recognizes this and triggers
a login. after a login, all auth-failed api calls are automatically retried.
only for "user:badAuth" is an error message displayed in the login form (e.g.
session expired).
in an ideal world, browsers would take care of most session management. a
server would indicate authentication is needed (like http basic auth), and the
browsers uses trusted ui to request credentials for the server & path. the
browser could use safer mechanism than sending original passwords to the
server, such as scram, along with a standard way to create sessions. for now,
web developers have to do authentication themselves: from showing the login
prompt, ensuring the right session/csrf cookies/localstorage/headers/etc are
sent with each request.
webauthn is a newer way to do authentication, perhaps we'll implement it in the
future. though hardware tokens aren't an attractive option for many users, and
it may be overkill as long as we still do old-fashioned authentication in smtp
& imap where passwords can be sent to the server.
for issue #58
all ui frontend code is now in typescript. we no longer need jshint, and we
build the frontend code during "make build".
this also changes tlsrpt types for a Report, not encoding field names with
dashes, but to keep them valid identifiers in javascript. this makes it more
conveniently to work with in the frontend, and works around a sherpats
limitation.
so a single user cannot fill up the disk.
by default, there is (still) no limit. a default can be set in the config file
for all accounts, and a per-account max size can be set that would override any
global setting.
this does not take into account disk usage of the index database. and also not
of any file system overhead.
we don't want external software to include internal details like mlog.
slog.Logger is/will be the standard.
we still have mlog for its helper functions, and its handler that logs in
concise logfmt used by mox.
packages that are not meant for reuse still pass around mlog.Log for
convenience.
we use golang.org/x/exp/slog because we also support the previous Go toolchain
version. with the next Go release, we'll switch to the builtin slog.
we were already accepting, processing and displaying incoming tls reports. now
we start tracking TLS connection and security-policy-related errors for
outgoing message deliveries as well. we send reports once a day, to the
reporting addresses specified in TLSRPT records (rua) of a policy domain. these
reports are about MTA-STS policies and/or DANE policies, and about
STARTTLS-related failures.
sending reports is enabled by default, but can be disabled through setting
NoOutgoingTLSReports in mox.conf.
only at the end of the implementation process came the realization that the
TLSRPT policy domain for DANE (MX) hosts are separate from the TLSRPT policy
for the recipient domain, and that MTA-STS and DANE TLS/policy results are
typically delivered in separate reports. so MX hosts need their own TLSRPT
policies.
config for the per-host TLSRPT policy should be added to mox.conf for existing
installs, in field HostTLSRPT. it is automatically configured by quickstart for
new installs. with a HostTLSRPT config, the "dns records" and "dns check" admin
pages now suggest the per-host TLSRPT record. by creating that record, you're
requesting TLS reports about your MX host.
gathering all the TLS/policy results is somewhat tricky. the tentacles go
throughout the code. the positive result is that the TLS/policy-related code
had to be cleaned up a bit. for example, the smtpclient TLS modes now reflect
reality better, with independent settings about whether PKIX and/or DANE
verification has to be done, and/or whether verification errors have to be
ignored (e.g. for tls-required: no header). also, cached mtasts policies of
mode "none" are now cleaned up once the MTA-STS DNS record goes away.
getting mox to compile required changing code in only a few places where
package "syscall" was used: for accessing file access times and for umask
handling. an open problem is how to start a process as an unprivileged user on
windows. that's why "mox serve" isn't implemented yet. and just finding a way
to implement it now may not be good enough in the near future: we may want to
starting using a more complete privilege separation approach, with a process
handling sensitive tasks (handling private keys, authentication), where we may
want to pass file descriptors between processes. how would that work on
windows?
anyway, getting mox to compile for windows doesn't mean it works properly on
windows. the largest issue: mox would normally open a file, rename or remove
it, and finally close it. this happens during message delivery. that doesn't
work on windows, the rename/remove would fail because the file is still open.
so this commit swaps many "remove" and "close" calls. renames are a longer
story: message delivery had two ways to deliver: with "consuming" the
(temporary) message file (which would rename it to its final destination), and
without consuming (by hardlinking the file, falling back to copying). the last
delivery to a recipient of a message (and the only one in the common case of a
single recipient) would consume the message, and the earlier recipients would
not. during delivery, the already open message file was used, to parse the
message. we still want to use that open message file, and the caller now stays
responsible for closing it, but we no longer try to rename (consume) the file.
we always hardlink (or copy) during delivery (this works on windows), and the
caller is responsible for closing and removing (in that order) the original
temporary file. this does cost one syscall more. but it makes the delivery code
(responsibilities) a bit simpler.
there is one more obvious issue: the file system path separator. mox already
used the "filepath" package to join paths in many places, but not everywhere.
and it still used strings with slashes for local file access. with this commit,
the code now uses filepath.FromSlash for path strings with slashes, uses
"filepath" in a few more places where it previously didn't. also switches from
"filepath" to regular "path" package when handling mailbox names in a few
places, because those always use forward slashes, regardless of local file
system conventions. windows can handle forward slashes when opening files, so
test code that passes path strings with forward slashes straight to go stdlib
file i/o functions are left unchanged to reduce code churn. the regular
non-test code, or test code that uses path strings in places other than
standard i/o functions, does have the paths converted for consistent paths
(otherwise we would end up with paths with mixed forward/backward slashes in
log messages).
windows cannot dup a listening socket. for "mox localserve", it isn't
important, and we can work around the issue. the current approach for "mox
serve" (forking a process and passing file descriptors of listening sockets on
"privileged" ports) won't work on windows. perhaps it isn't needed on windows,
and any user can listen on "privileged" ports? that would be welcome.
on windows, os.Open cannot open a directory, so we cannot call Sync on it after
message delivery. a cursory internet search indicates that directories cannot
be synced on windows. the story is probably much more nuanced than that, with
long deep technical details/discussions/disagreement/confusion, like on unix.
for "mox localserve" we can get away with making syncdir a no-op.
