notmuch/test/T357-index-decryption.sh
Daniel Kahn Gillmor 29648a137c crypto: actually stash session keys when decrypt=true
If you're going to store the cleartext index of an encrypted message,
in most situations you might just as well store the session key.
Doing this storage has efficiency and recoverability advantages.

Combined with a schedule of regular OpenPGP subkey rotation and
destruction, this can also offer security benefits, like "deletable
e-mail", which is the store-and-forward analog to "forward secrecy".

But wait, i hear you saying, i have a special need to store cleartext
indexes but it's really bad for me to store session keys!  Maybe
(let's imagine) i get lots of e-mails with incriminating photos
attached, and i want to be able to search for them by the text in the
e-mail, but i don't want someone with access to the index to be
actually able to see the photos themselves.

Fret not, the next patch in this series will support your wacky
uncommon use case.
2017-12-08 08:08:47 -04:00

280 lines
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#!/usr/bin/env bash
# TODO: test index.decryption=failed
test_description='indexing decrypted mail'
. $(dirname "$0")/test-lib.sh || exit 1
##################################################
add_gnupg_home
# get key fingerprint
FINGERPRINT=$(gpg --no-tty --list-secret-keys --with-colons --fingerprint | grep '^fpr:' | cut -d: -f10)
# create a test encrypted message
test_begin_subtest 'emacs delivery of encrypted message'
test_expect_success \
'emacs_fcc_message \
"test encrypted message for cleartext index 001" \
"This is a test encrypted message with a wumpus.\n" \
"(mml-secure-message-encrypt)"'
test_begin_subtest "search for unindexed cleartext"
output=$(notmuch search wumpus)
expected=''
test_expect_equal \
"$output" \
"$expected"
# create a test encrypted message that is indexed in the clear
test_begin_subtest 'emacs delivery of encrypted message'
test_expect_success \
'emacs_fcc_message --decrypt=true \
"test encrypted message for cleartext index 002" \
"This is a test encrypted message with a wumpus.\n" \
"(mml-secure-message-encrypt)"'
test_begin_subtest "emacs delivery of encrypted message, indexed cleartext"
output=$(notmuch search wumpus)
expected='thread:0000000000000002 2000-01-01 [1/1] Notmuch Test Suite; test encrypted message for cleartext index 002 (encrypted inbox)'
test_expect_equal \
"$output" \
"$expected"
# and the same search, but by property ($expected is untouched):
test_begin_subtest "emacs search by property for one message"
output=$(notmuch search property:index.decryption=success)
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "show the message body of the encrypted message"
notmuch dump wumpus
output=$(notmuch show wumpus | awk '/^\014part}/{ f=0 }; { if (f) { print $0 } } /^\014part{ ID: 3/{ f=1 }')
expected='This is a test encrypted message with a wumpus.'
if [ $NOTMUCH_HAVE_GMIME_SESSION_KEYS -eq 0 ]; then
test_subtest_known_broken
fi
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "message should go away after deletion"
# cache the message in an env var and remove it:
fname=$(notmuch search --output=files wumpus)
contents="$(notmuch show --format=raw wumpus)"
rm -f "$fname"
notmuch new
output=$(notmuch search wumpus)
expected=''
test_expect_equal \
"$output" \
"$expected"
# try reinserting it without decryption, should stay the same:
test_begin_subtest "message cleartext not present after insert"
notmuch insert --folder=sent <<<"$contents"
output=$(notmuch search wumpus)
test_expect_equal \
"$output" \
"$expected"
# try reinserting it with decryption, should appear again, but now we
# have two copies of the message:
test_begin_subtest "message cleartext is present after reinserting with --decrypt=true"
notmuch insert --folder=sent --decrypt=true <<<"$contents"
output=$(notmuch search wumpus)
expected='thread:0000000000000003 2000-01-01 [1/1(2)] Notmuch Test Suite; test encrypted message for cleartext index 002 (encrypted inbox unread)'
test_expect_equal \
"$output" \
"$expected"
# remove all copies
test_begin_subtest "delete all copies of the message"
mid="$(notmuch search --output=messages wumpus)"
rm -f $(notmuch search --output=files wumpus)
notmuch new
output=$(notmuch search "id:$mid")
expected=''
test_expect_equal \
"$output" \
"$expected"
# try inserting it with decryption, should appear as a single copy
# (note: i think thread id skips 4 because of duplicate message-id
# insertion, above)
test_begin_subtest "message cleartext is present with insert --decrypt=true"
notmuch insert --folder=sent --decrypt=true <<<"$contents"
output=$(notmuch search wumpus)
expected='thread:0000000000000005 2000-01-01 [1/1] Notmuch Test Suite; test encrypted message for cleartext index 002 (encrypted inbox unread)'
test_expect_equal \
"$output" \
"$expected"
# add a tag to all messages to ensure that it stays after reindexing
test_begin_subtest 'tagging all messages'
test_expect_success 'notmuch tag +blarney "encrypted message"'
test_begin_subtest "verify that tags have not changed"
output=$(notmuch search tag:blarney)
expected='thread:0000000000000001 2000-01-01 [1/1] Notmuch Test Suite; test encrypted message for cleartext index 001 (blarney encrypted inbox)
thread:0000000000000005 2000-01-01 [1/1] Notmuch Test Suite; test encrypted message for cleartext index 002 (blarney encrypted inbox unread)'
test_expect_equal \
"$output" \
"$expected"
# see if first message shows up after reindexing with --decrypt=true (same $expected, untouched):
test_begin_subtest 'reindex old messages'
test_expect_success 'notmuch reindex --decrypt=true tag:encrypted and not property:index.decryption=success'
test_begin_subtest "reindexed encrypted message, including cleartext"
output=$(notmuch search wumpus)
test_expect_equal \
"$output" \
"$expected"
# and the same search, but by property ($expected is untouched):
test_begin_subtest "emacs search by property for both messages"
output=$(notmuch search property:index.decryption=success)
test_expect_equal \
"$output" \
"$expected"
# try a simple reindex
test_begin_subtest 'reindex in auto mode'
test_expect_success 'notmuch reindex tag:encrypted and property:index.decryption=success'
test_begin_subtest "reindexed encrypted messages, should not have changed"
output=$(notmuch search wumpus)
if [ $NOTMUCH_HAVE_GMIME_SESSION_KEYS -eq 0 ]; then
test_subtest_known_broken
fi
test_expect_equal \
"$output" \
"$expected"
# try to remove cleartext indexing
test_begin_subtest 'reindex without cleartext'
test_expect_success 'notmuch reindex --decrypt=false tag:encrypted and property:index.decryption=success'
test_begin_subtest "reindexed encrypted messages, without cleartext"
output=$(notmuch search wumpus)
expected=''
test_expect_equal \
"$output" \
"$expected"
# ensure no session keys are present:
test_begin_subtest 'reindex using only session keys'
test_expect_success 'notmuch reindex tag:encrypted and property:index.decryption=success'
test_begin_subtest "reindexed encrypted messages, decrypting only with session keys"
output=$(notmuch search wumpus)
expected=''
test_expect_equal \
"$output" \
"$expected"
# and the same search, but by property ($expected is untouched):
test_begin_subtest "emacs search by property with both messages unindexed"
output=$(notmuch search property:index.decryption=success)
test_expect_equal \
"$output" \
"$expected"
# ensure that the tags remain even when we are dropping the cleartext.
test_begin_subtest "verify that tags remain without cleartext"
output=$(notmuch search tag:blarney)
expected='thread:0000000000000001 2000-01-01 [1/1] Notmuch Test Suite; test encrypted message for cleartext index 001 (blarney encrypted inbox)
thread:0000000000000005 2000-01-01 [1/1] Notmuch Test Suite; test encrypted message for cleartext index 002 (blarney encrypted inbox unread)'
test_expect_equal \
"$output" \
"$expected"
add_email_corpus crypto
test_begin_subtest "indexing message fails when secret key not available"
notmuch reindex --decrypt=true id:simple-encrypted@crypto.notmuchmail.org
output=$(notmuch dump )
expected='#notmuch-dump batch-tag:3 config,properties,tags
+encrypted +inbox +unread -- id:simple-encrypted@crypto.notmuchmail.org
#= simple-encrypted@crypto.notmuchmail.org index.decryption=failure'
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "cannot find cleartext index"
output=$(notmuch search sekrit)
expected=''
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "cleartext index recovery on reindexing with stashed session keys"
notmuch restore <<EOF
#notmuch-dump batch-tag:3 config,properties,tags
#= simple-encrypted@crypto.notmuchmail.org session-key=9%3AFC09987F5F927CC0CC0EE80A96E4C5BBF4A499818FB591207705DFDDD6112CF9
EOF
notmuch reindex id:simple-encrypted@crypto.notmuchmail.org
output=$(notmuch search sekrit)
expected='thread:0000000000000001 2016-12-22 [1/1] Daniel Kahn Gillmor; encrypted message (encrypted inbox unread)'
if [ $NOTMUCH_HAVE_GMIME_SESSION_KEYS -eq 0 ]; then
test_subtest_known_broken
fi
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "notmuch reply should show cleartext if session key is present"
output=$(notmuch reply id:simple-encrypted@crypto.notmuchmail.org | grep '^>')
expected='> This is a top sekrit message.'
if [ $NOTMUCH_HAVE_GMIME_SESSION_KEYS -eq 0 ]; then
test_subtest_known_broken
fi
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "notmuch show should show cleartext if session key is present"
output=$(notmuch show id:simple-encrypted@crypto.notmuchmail.org | awk '/^\014part}/{ f=0 }; { if (f) { print $0 } } /^\014part{ ID: 3/{ f=1 }')
expected='This is a top sekrit message.'
if [ $NOTMUCH_HAVE_GMIME_SESSION_KEYS -eq 0 ]; then
test_subtest_known_broken
fi
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "notmuch show should show nothing if decryption is explicitly disallowed"
output=$(notmuch show --decrypt=false id:simple-encrypted@crypto.notmuchmail.org | awk '/^\014part}/{ f=0 }; { if (f) { print $0 } } /^\014part{ ID: 3/{ f=1 }')
expected='Non-text part: application/octet-stream'
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "purging stashed session keys should lose access to the cleartext"
notmuch reindex --decrypt=false id:simple-encrypted@crypto.notmuchmail.org
output=$(notmuch search sekrit)
expected=''
test_expect_equal \
"$output" \
"$expected"
test_begin_subtest "and cleartext should be unrecoverable now that there are no stashed session keys"
notmuch dump
notmuch reindex --decrypt=true id:simple-encrypted@crypto.notmuchmail.org
output=$(notmuch search sekrit)
expected=''
test_expect_equal \
"$output" \
"$expected"
# TODO: test removal of a message from the message store between
# indexing and reindexing.
# TODO: insert the same message into the message store twice, index,
# remove one of them from the message store, and then reindex.
# reindexing should return a failure but the message should still be
# present? -- or what should the semantics be if you ask to reindex a
# message whose underlying files have been renamed or moved or
# removed?
test_done