notmuch/test/T356-protected-headers.sh
Daniel Kahn Gillmor b7b553e732 cli/reply: ensure encrypted Subject: line does not leak in the clear
Now that we can decrypt headers, we want to make sure that clients
using "notmuch reply" to prepare a reply don't leak cleartext in their
subject lines.  In particular, the ["reply-headers"]["Subject"] should
by default show the external Subject.

A replying MUA that intends to protect the Subject line should show
the user the Subject from ["original"]["headers"]["Subject"] instead
of using ["reply-headers"]["Subject"].

This minor asymmetry with "notmuch show" is intentional.  While both
tools always render the cleartext subject line when they know it (in
["headers"]["Subject"] for "notmuch show" and in
["original"]["headers"]["Subject"] for "notmuch reply"), "notmuch
reply" should never leak something that should stay under encrypted
cover in "reply-headers".

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
2019-05-29 08:14:32 -03:00

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#!/usr/bin/env bash
# TODO:
# * check S/MIME as well as PGP/MIME
test_description='Message decryption with protected headers'
. $(dirname "$0")/test-lib.sh || exit 1
##################################################
add_gnupg_home
add_email_corpus protected-headers
test_begin_subtest "verify protected header is not visible without decryption"
output=$(notmuch show --format=json id:protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'no_crypto_info:[0][0][0]["crypto"]={}' \
'subject:[0][0][0]["headers"]["Subject"]="Subject Unavailable"'
test_begin_subtest "verify protected header is visible with decryption"
output=$(notmuch show --decrypt=true --format=json id:protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "full", "header-mask": {"Subject": "Subject Unavailable"}}}' \
'subject:[0][0][0]["headers"]["Subject"]="This is a protected header"'
test_begin_subtest "when no external header is present, show masked subject as null"
output=$(notmuch show --decrypt=true --format=json id:subjectless-protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "full", "header-mask": {"Subject": null}}}' \
'subject:[0][0][0]["headers"]["Subject"]="This is a protected header"'
test_begin_subtest "misplaced protected headers should not be made visible during decryption"
output=$(notmuch show --decrypt=true --format=json id:misplaced-protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "full"}}' \
'subject:[0][0][0]["headers"]["Subject"]="Subject Unavailable"'
test_begin_subtest "verify double-wrapped phony protected header is not visible when inner decryption fails"
output=$(notmuch show --decrypt=true --format=json id:double-wrapped-with-phony-protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "full"}}' \
'subject:[0][0][0]["headers"]["Subject"]="Subject Unavailable"'
test_begin_subtest "cleartext phony protected headers should not be made visible when decryption fails"
output=$(notmuch show --decrypt=true --format=json id:phony-protected-header-bad-encryption@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'no_crypto_info:[0][0][0]["crypto"]={}' \
'subject:[0][0][0]["headers"]["Subject"]="Subject Unavailable"'
test_begin_subtest "wrapped protected headers should not be made visible during decryption"
output=$(notmuch show --decrypt=true --format=json id:wrapped-protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "partial"}}' \
'subject:[0][0][0]["headers"]["Subject"]="[mailing-list] Subject Unavailable"'
test_begin_subtest "internal headers without protected-header attribute should be skipped"
output=$(notmuch show --decrypt=true --format=json id:no-protected-header-attribute@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "full"}}' \
'subject:[0][0][0]["headers"]["Subject"]="Subject Unavailable"'
test_begin_subtest "verify nested message/rfc822 protected header is visible"
output=$(notmuch show --decrypt=true --format=json id:nested-rfc822-message@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"decrypted": {"status": "full", "header-mask": {"Subject": "Subject Unavailable"}}}' \
'subject:[0][0][0]["headers"]["Subject"]="This is a message using draft-melnikov-smime-header-signing"'
test_begin_subtest "show cryptographic envelope on signed mail"
output=$(notmuch show --verify --format=json id:simple-signed-mail@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"signed": {"status": [{"created": 1525609971, "fingerprint": "'$FINGERPRINT'", "userid": "'"$SELF_USERID"'", "status": "good"}]}}'
test_begin_subtest "verify signed protected header"
output=$(notmuch show --verify --format=json id:signed-protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:[0][0][0]["crypto"]={"signed": {"status": [{"created": 1525350527, "fingerprint": "'$FINGERPRINT'", "userid": "'"$SELF_USERID"'", "status": "good"}], "headers": ["Subject"]}}'
test_begin_subtest "protected subject does not leak by default in replies"
output=$(notmuch reply --decrypt=true --format=json id:protected-header@crypto.notmuchmail.org)
test_json_nodes <<<"$output" \
'crypto:["original"]["crypto"]={"decrypted": {"status": "full", "header-mask": {"Subject": "Subject Unavailable"}}}' \
'subject:["original"]["headers"]["Subject"]="This is a protected header"' \
'reply-subject:["reply-headers"]["Subject"]="Re: Subject Unavailable"'
test_done