the smtp extension, rfc 4865.
also implement in the webmail.
the queueing/delivery part hardly required changes: we just set the first
delivery time in the future instead of immediately.
still have to find the first client that implements it.
to start composing a message.
the help popup now has a button to register the "mailto:" links with the mox
webmail (typically only works over https, not all browsers support it).
the mailto links are specified in 6068. we support the to/cc/bcc/subject/body
parameters. other parameters should be seen as custom headers, but we don't
support messages with custom headers at all at the moment, so we ignore them.
we now also turn text of the form "mailto:user@host" into a clickable link
(will not be too common). we could be recognizing any "x@x.x" as email address
and make them clickable in the future.
thanks to Hans-Jörg for explaining this functionality.
before, we showed the xn-- ascii names, along with the unicode name. but users
of internationalized email don't want to see any xn-- names. we now put those
in an html title attribute for some cases, so you can still see them if you
really want to, by hovering.
after talking to arnt at fosdem.
if a browser is ahead just a few seconds, we would show "-<1min", not great.
just show "<1min" in that case. we'll still show negative age if drift is more
than 1 minute, which seems like a good hint to get time fixed on either client
or server.
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
mox was already strict in its "\r\n.\r\n" handling for end-of-message in an
smtp transaction.
due to a mostly unrelated bug, sequences of "\nX\n", including "\n.\n" were
rejected with a "local processing error".
the sequence "\r\n.\n" dropped the dot, not necessarily a big problem, this is
unlikely to happen in a legimate transaction and the behaviour not
unreasonable.
we take this opportunity to reject all bare \r. we detect all slightly
incorrect combinations of "\r\n.\r\n" with an error mentioning smtp smuggling,
in part to appease the tools checking for it.
smtp errors are 500 "bad syntax", and mention smtp smuggling.
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.
- prometheus is now behind an interface, they aren't dependencies for the
reusable components anymore.
- some dependencies have been inverted: instead of packages importing a main
package to get configuration, the main package now sets configuration in
these packages. that means fewer internals are pulled in.
- some functions now have new parameters for values that were retrieved from
package "mox-".
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.
i'm not sure this is good enough.
this is based on field MsgFromValidation, but it doesn't hold the full DMARC information.
we also don't know mailing list-status for all historic messages.
so the red underline can occur too often.
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.
we were trying to offset the timezone, but that makes no sense: we already
created a date in the local timezone based on (milli)seconds passed. so we can
just use that date instead of calculating a wrong date.
in smtpserver, we store dmarc evaluations (under the right conditions).
in dmarcdb, we periodically (hourly) send dmarc reports if there are
evaluations. for failed deliveries, we deliver the dsn quietly to a submailbox
of the postmaster mailbox.
this is on by default, but can be disabled in mox.conf.
with requiretls, the tls verification mode/rules for email deliveries can be
changed by the sender/submitter. in two ways:
1. "requiretls" smtp extension to always enforce verified tls (with mta-sts or
dnssec+dane), along the entire delivery path until delivery into the final
destination mailbox (so entire transport is verified-tls-protected).
2. "tls-required: no" message header, to ignore any tls and tls verification
errors even if the recipient domain has a policy that requires tls verification
(mta-sts and/or dnssec+dane), allowing delivery of non-sensitive messages in
case of misconfiguration/interoperability issues (at least useful for sending
tls reports).
we enable requiretls by default (only when tls is active), for smtp and
submission. it can be disabled through the config.
for each delivery attempt, we now store (per recipient domain, in the account
of the sender) whether the smtp server supports starttls and requiretls. this
support is shown (after having sent a first message) in the webmail when
sending a message (the previous 3 bars under the address input field are now 5
bars, the first for starttls support, the last for requiretls support). when
all recipient domains for a message are known to implement requiretls,
requiretls is automatically selected for sending (instead of "default" tls
behaviour). users can also select the "fallback to insecure" to add the
"tls-required: no" header.
new metrics are added for insight into requiretls errors and (some, not yet
all) cases where tls-required-no ignored a tls/verification error.
the admin can change the requiretls status for messages in the queue. so with
default delivery attempts, when verified tls is required by failing, an admin
could potentially change the field to "tls-required: no"-behaviour.
messages received (over smtp) with the requiretls option, get a comment added
to their Received header line, just before "id", after "with".
the bar is currently showing 3 properties:
1. mta-sts enforced;
2. mx lookup returned dnssec-signed response;
3. first delivery destination host has dane records
the colors are: red for not-implemented, green for implemented, gray for error,
nothing for unknown/irrelevant.
the plan is to implement "requiretls" soon and start caching per domain whether
delivery can be done with starttls and whether the domain supports requiretls.
and show that in two new parts of the bar.
thanks to damian poddebniak for pointing out that security indicators should
always be visible, not only for positive/negative result. otherwise users won't
notice their absence.
so full name/email address is visible.
using a hidden grid element that gets the same content as the input element.
from https://css-tricks.com/auto-growing-inputs-textareas/
a recent commit probably also make the compose window full-screen-width on
chrome, this restores to the intended behaviour of a less wide default size.
if you add multiple address fields, the compose window will still grow. not
great, in the future, we should make the compose window resizable by dragging.
the textarea is resizable (though it's not convenient to do in firefox which
only shows a dragcorner in the bottomright, usually located in the bottom
corner of the screen, so there is little space left to drag the corner; the
workaround is to move the window temporarily).
by using a String object as the textarea child. instead of a regular js string
that would be unicode-block-switch-highlighted, which would cause it to be
split into parts, with odd or even parts added as span elements, which the
textarea would then ignore.
according to the rfc's (2231, and 2047), non-ascii filenames in content-type
and content-disposition headers should be encoded like this:
Content-Type: text/plain; name*=utf-8''hi%E2%98%BA.txt
Content-Disposition: attachment; filename*=utf-8''hi%E2%98%BA.txt
and that is what the Go standard library mime.ParseMediaType and
mime.FormatMediaType parse and generate.
this is what thunderbird sends:
Content-Type: text/plain; charset=UTF-8; name="=?UTF-8?B?aGnimLoudHh0?="
Content-Disposition: attachment; filename*=UTF-8''%68%69%E2%98%BA%2E%74%78%74
(thunderbird will also correctly split long filenames over multiple parameters,
named "filename*0*", "filename*1*", etc.)
this is what gmail sends:
Content-Type: text/plain; charset="US-ASCII"; name="=?UTF-8?B?aGnimLoudHh0?="
Content-Disposition: attachment; filename="=?UTF-8?B?aGnimLoudHh0?="
i cannot find where the q/b-word encoded values in "name" and "filename" are
allowed. until that time, we try parsing them unless in pedantic mode.
we didn't generate correctly encoded filenames yet, this commit also fixes that.
for issue #82 by mattfbacon, thanks for reporting!
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.
