
Mutt
====

Mutt is a fast, standards-compliant, efficient MUA (Mail User Agent). In some areas it works better than Thunderbird+Enigmail, and is certainly faster and more responsive.

Mutt lacks true MTA (Message Transfer Agent aka "SMTP client") and MRA (Mail
Retrieval Agent aka "IMAP/POP3 client"), thus there are some provisions
built-in. In principle it is only mail reader and composer. You may install
true MTA such as [Postfix](https://www.qubes-os.org/doc/postfix/) or Exim and MRA such as
[Fetchmail](https://www.qubes-os.org/doc/fetchmail/). Alternatively you can synchronize your mailbox
using [OfflineIMAP](https://github.com/OfflineIMAP/offlineimap) and just stick
to integrated SMTP support. You can even use integrated IMAP client, but it is
not very convenient.

Installation
------------

`dnf install mutt cyrus-sasl-plain`

`cyrus-sasl-plain` package is necessary for SMTP authentication to work.

Configuration
-------------

Mutt generally works out of the box. This configuration guide discusses only Qubes-specific setup. In this example we will have one TemplateVM and several AppVMs. It also takes advantage of [SplitGPG](https://www.qubes-os.org/doc/split-gpg/), which is assumed to be already working.

**NOTE:** this requires `qubes-gpg-split >= 2.0.9`. 2.0.8 and earlier contains bug which causes this setup to hang in specific situations and does not allow to list keys.

First, paste this to `/etc/Muttrc.local` in TemplateVM:

~~~
# specify your key or override in ~/.mutt/muttrc in AppVM
set pgp_sign_as="0xDEADBEEF"

set pgp_use_gpg_agent = no

# this needs qubes-gpg-split >= 2.0.8; 2.0.7 end earlier has had a deadlock on this
set pgp_decode_command="qubes-gpg-client-wrapper --status-fd=2 --batch %f"
#set pgp_decode_command="gpg --status-fd=2 %?p?--passphrase-fd=0? --no-verbose --quiet --batch --output - %f"

set pgp_decrypt_command="$pgp_decode_command"

set pgp_verify_command="qubes-gpg-client-wrapper --status-fd=2 --no-verbose --quiet --batch --output - --verify %s %f"

set pgp_sign_command="qubes-gpg-client-wrapper --batch --armor --detach-sign --textmode %?a?-u %a? %f"
set pgp_clearsign_command="qubes-gpg-client-wrapper --batch --armor --textmode --clearsign %?a?-u %a? %f"

# I found no option to add Charset armor header when it is UTF-8, since this is
# default (as specified in RFC4880). This is needed to workaround bug in
# Enigmail, which ignores RFC and without this header Thunderbird interprets
# plaintext as us-ascii. See https://sourceforge.net/p/enigmail/bugs/38/.

### also note you must specify absolute path of pgpewrap when using debian
### e.g. /usr/lib/mutt/pgpewrap

set pgp_encrypt_only_command="pgpewrap qubes-gpg-client-wrapper --batch --textmode --armor --always-trust %?a?--encrypt-to %a? --encrypt -- -r %r -- %f | sed -e '2iCharset: UTF-8'"
set pgp_encrypt_sign_command="pgpewrap qubes-gpg-client-wrapper --batch --textmode --armor --always-trust %?a?--encrypt-to %a? --encrypt --sign %?a?-u %a? -- -r %r -- %f | sed -e '2iCharset: UTF-8'"

# we need to import both into vault and locally wrt $pgp_verify_command
set pgp_import_command="qubes-gpg-import-key %f; gpg --no-verbose --import %f"

# those are unsupported by split-gpg
set pgp_export_command="gpg --no-verbose --export --armor %r"
set pgp_verify_key_command="gpg --no-verbose --batch --fingerprint --check-sigs %r"

# read in the public key ring
set pgp_list_pubring_command="qubes-gpg-client-wrapper --no-verbose --batch --quiet --with-colons --list-keys %r"

# read in the secret key ring
set pgp_list_secring_command="qubes-gpg-client-wrapper --no-verbose --batch --quiet --with-colons --list-secret-keys %r"

# this set the number of seconds to keep in memory the passpharse used to encrypt/sign
# the more the less secure it will be
set pgp_timeout=600

# it's a regexp used against the GPG output: if it matches some line of the output
# then mutt considers the message a good signed one (ignoring the GPG exit code)
#set pgp_good_sign="^gpg: Good signature from"
set pgp_good_sign="^\\[GNUPG:\\] GOODSIG"

# mutt uses by default PGP/GPG to sign/encrypt messages
# if you want to use S-mime instead set the smime_is_default variable to yes

# automatically sign all outcoming messages
set crypt_autosign=yes
# sign only replies to signed messages
#set crypt_replysign

# automatically encrypt outcoming messages
#set crypt_autoencrypt=yes
# encrypt only replies to signed messages
set crypt_replyencrypt=yes
# encrypt and sign replies to encrypted messages
set crypt_replysignencrypted=yes

# automatically verify the sign of a message when opened
set crypt_verify_sig=yes

# disable use of gpgme, which interferes with Split-GPG
# and defaults to 'yes' on Debian 9 and higher
set crypt_use_gpgme=no

send-hook "~A" set pgp_autoinline=no crypt_autoencrypt=no
send-hook "~t @invisiblethingslab\.com" set crypt_autoencrypt=yes

# vim:ft=muttrc
~~~

Then shutdown your TemplateVM. Next open your AppVM, create file `/home/user/.mutt/muttrc` and adjust for your needs:

~~~
#
# accounts
#
set from = "Wojciech Zygmunt Porczyk <woju@invisiblethingslab.com>"
alternates '^woju@invisiblethingslab\.com$'
alternates '^wojciech@porczyk\.eu$'

#
# crypto
#
set pgp_sign_as = "0xDEADBEEF"
send-hook "~t @my\.family\.com" set crypt_autoencrypt=no

#
# lists
#

# google groups
lists .*@googlegroups\.com

subscribe (qubes-(users|devel)|othergroup)@googlegroups\.com
fcc-save-hook qubes-users@googlegroups\.com =list/qubes-users/
fcc-save-hook qubes-devel@googlegroups\.com =list/qubes-devel/
fcc-save-hook othergroup@googlegroups\.com =list/othergroup/
~~~

You may also create `/home/user/.signature`:

~~~
regards,
Wojciech Porczyk
~~~

Some additional useful settings
-------------------------------

In `muttrc`:

    ###qubes integration stuff

    #open links in a dispvm using urlview
    #see below for sample .urlview
    macro pager \cb <pipe-entry>'urlview'<enter> 'Follow links with urlview'

    #override default mailcap MIME settings with qvm-open-in-dvm calls
    #see sample .mailcap below
    set mailcap_path=~/.mailcap

    bind attach <return>    view-mailcap

Debian-specific options:

    #use debian mutt-patched package for mailbox sidebar hack
    set sidebar_width = 30
    set sidebar_visible = no
    set sidebar_delim='|'

    #show/hide sidebar
    macro index S '<enter-command>toggle sidebar_visible<enter>'
    macro pager S '<enter-command>toggle sidebar_visible<enter>'

    #navigate the sidebar folders
    bind index CP sidebar-prev
    bind index CN sidebar-next
    bind index CO sidebar-open
    bind pager CP sidebar-prev
    bind pager CN sidebar-next


In `.urlview`:

    ### TODO: this doesn't work with encrypted emails --
    ### urlview can't find the links
    ###
    COMMAND qvm-open-in-dvm %s


In `.mailcap`:

    ### TODO: override most/all default mailcap settings to prevent
    ### opening in muttvm
    ### is there a way to do this polymorphically? i.e. not
    ### listing every damn mimetype by hand
    ###
    ### also would be convenient to use mailcap's TEST feature to
    ### show some html in mutt pager (e.g. with w3m, links or html2text),
    ### else open others in dispvm
    
    # MS Word documents
    application/msword; qvm-open-in-dvm %s
    application/vnd.oasis.opendocument.spreadsheet; qvm-open-in-dvm %s
    application/vnd.oasis.opendocument.text; qvm-open-in-dvm %s
    
    # Images
    image/jpg; qvm-open-in-dvm %s
    image/jpeg; qvm-open-in-dvm %s
    image/png; qvm-open-in-dvm %s
    image/gif; qvm-open-in-dvm %s
    
    # PDFs
    application/pdf; qvm-open-in-dvm %s
    
    # HTML
    text/html; w3m -T text/html '%s' | cat --squeeze-blank; nametemplate=%s.html; copiousoutput
    text/html; qvm-open-in-dvm %s
