[PATCH 4/4] cli/show: emit new whole-message crypto status output

[Daniel Kahn Gillmor <dkg@fifthhorseman.net>]

This allows MUAs that don't want to think about per-mime-part
cryptographic status to have a simple high-level overview of the
message's cryptographic state.

Sensibly structured encrypted and/or signed messages will work fine
with this.  The only requirement for the simplest encryption + signing
is that the message have all of its encryption and signing protection
(the "cryptographic envelope") in a contiguous set of MIME layers at
the very outside of the message itself.

This is because messages with some subparts signed or encrypted, but
with other subparts with no cryptographic protection is very difficult
to reason about, and even harder for the user to make sense of or work
with.

For further characterization of the Cryptographic Envelope and some of
the usability tradeoffs, see here:

   https://dkg.fifthhorseman.net/blog/e-mail-cryptography.html#cryptographic-envelope
---
 devel/schemata      | 18 ++++++++++++++++++
 notmuch-show.c      | 29 +++++++++++++++++++++++++++++
 test/T350-crypto.sh | 19 +++++++++++++++----
 test/T355-smime.sh  |  5 +++--
 4 files changed, 65 insertions(+), 6 deletions(-)

diff --git a/devel/schemata b/devel/schemata
index 42b1bcf3..33633ab3 100644
--- a/devel/schemata
+++ b/devel/schemata
@@ -33,6 +33,8 @@ v3
 v4
 - replace signature error integer bitmask with a set of flags for
   individual errors.
+- (notmuch 0.29) added message.crypto to identify overall message
+  cryptographic state
 
 Common non-terminals
 --------------------
@@ -73,9 +75,25 @@ message = {
     tags:           [string*],
 
     headers:        headers,
+    crypto?:        crypto,   # omitted if crypto disabled, or if no part was signed or encrypted.
     body?:          [part]    # omitted if --body=false
 }
 
+# when showing the message, was any or all of it decrypted?
+msgdecstatus: "full"|"partial"
+
+# The overall cryptographic state of the message as a whole:
+crypto = {
+    signed?:    {
+                  status:      sigstatus,
+                  # was the set of signatures described under encrypted cover?
+                  encrypted:   bool,
+                },
+    decrypted?: {
+                  status: msgdecstatus,
+                }
+}
+
 # A MIME part (format_part_sprinter)
 part = {
     id:             int|string, # part id (currently DFS part number)
diff --git a/notmuch-show.c b/notmuch-show.c
index 88699e90..575b1654 100644
--- a/notmuch-show.c
+++ b/notmuch-show.c
@@ -648,6 +648,35 @@ format_part_sprinter (const void *ctx, sprinter_t *sp, mime_node_t *node,
 	    format_part_sprinter (ctx, sp, mime_node_child (node, 0), true, include_html);
 	    sp->end (sp);
 	}
+
+	if (notmuch_format_version >= 4) {
+	    const _notmuch_message_crypto_t *msg_crypto = mime_node_get_message_crypto_status (node);
+	    if (msg_crypto->sig_list ||
+		msg_crypto->decryption_status != NOTMUCH_MESSAGE_DECRYPTED_NONE) {
+		sp->map_key (sp, "crypto");
+		sp->begin_map (sp);
+		if (msg_crypto->sig_list) {
+		    sp->map_key (sp, "signed");
+		    sp->begin_map (sp);
+		    sp->map_key (sp, "status");
+		    format_part_sigstatus_sprinter (sp, msg_crypto->sig_list);
+		    if (msg_crypto->signature_encrypted) {
+			sp->map_key (sp, "encrypted");
+			sp->boolean (sp, msg_crypto->signature_encrypted);
+		    }
+		    sp->end (sp);
+		}
+		if (msg_crypto->decryption_status != NOTMUCH_MESSAGE_DECRYPTED_NONE) {
+		    sp->map_key (sp, "decrypted");
+		    sp->begin_map (sp);
+		    sp->map_key (sp, "status");
+		    sp->string (sp, msg_crypto->decryption_status == NOTMUCH_MESSAGE_DECRYPTED_FULL ? "full" : "partial");
+		    sp->end (sp);
+		}
+		sp->end (sp);
+	    }
+	}
+
 	sp->end (sp);
 	return;
     }
diff --git a/test/T350-crypto.sh b/test/T350-crypto.sh
index 2f793e96..a6d8bebd 100755
--- a/test/T350-crypto.sh
+++ b/test/T350-crypto.sh
@@ -25,7 +25,7 @@ test_expect_equal "$output" "thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; t
 test_begin_subtest "signature verification"
 output=$(notmuch show --format=json --verify subject:"test signed message 001" \
     | notmuch_json_show_sanitize \
-    | sed -e 's|"created": [1234567890]*|"created": 946728000|')
+    | sed -e 's|"created": [1234567890]*|"created": 946728000|g')
 expected='[[[{"id": "XXXXX",
  "match": true,
  "excluded": false,
@@ -33,6 +33,7 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["inbox","signed"],
+ "crypto": {"signed": {"status": [{ "status": "good", "created": 946728000, "fingerprint": "'$FINGERPRINT'"}]}},
  "headers": {"Subject": "test signed message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
@@ -73,6 +74,7 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["inbox","signed"],
+ "crypto": {"signed": {"status": [{ "status": "bad", "keyid": "'$(echo $FINGERPRINT | cut -c 25-)'"}]}},
  "headers": {"Subject": "bad signed message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
@@ -142,7 +144,7 @@ echo "${FINGERPRINT}:6:" | gpg --no-tty --import-ownertrust >>"$GNUPGHOME"/trust
 gpg --no-tty --check-trustdb >>"$GNUPGHOME"/trust.log 2>&1
 output=$(notmuch show --format=json --verify subject:"test signed message 001" \
     | notmuch_json_show_sanitize \
-    | sed -e 's|"created": [1234567890]*|"created": 946728000|')
+    | sed -e 's|"created": [1234567890]*|"created": 946728000|g')
 expected='[[[{"id": "XXXXX",
  "match": true,
  "excluded": false,
@@ -150,6 +152,8 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["inbox","signed"],
+ "crypto": {"signed": {"status": [{ "status": "good", "created": 946728000, "fingerprint": "'$FINGERPRINT'",
+                                    "userid": "Notmuch Test Suite <test_suite@notmuchmail.org> (INSECURE!)"}]}},
  "headers": {"Subject": "test signed message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
@@ -176,7 +180,7 @@ test_begin_subtest "signature verification with signer key unavailable"
 mv "${GNUPGHOME}"{,.bak}
 output=$(notmuch show --format=json --verify subject:"test signed message 001" \
     | notmuch_json_show_sanitize \
-    | sed -e 's|"created": [1234567890]*|"created": 946728000|')
+    | sed -e 's|"created": [1234567890]*|"created": 946728000|g')
 expected='[[[{"id": "XXXXX",
  "match": true,
  "excluded": false,
@@ -184,6 +188,7 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["inbox","signed"],
+ "crypto": {"signed": {"status": [{"errors": {"key-missing": true}, "keyid": "'$(echo $FINGERPRINT | cut -c 25-)'", "status": "error"}]}},
  "headers": {"Subject": "test signed message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
@@ -263,6 +268,7 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["encrypted","inbox"],
+ "crypto": {"decrypted": {"status": "full"}},
  "headers": {"Subject": "test encrypted message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
@@ -350,7 +356,7 @@ test_begin_subtest "decryption + signature verification"
 test_subtest_broken_gmime_2
 output=$(notmuch show --format=json --decrypt=true subject:"test encrypted message 002" \
     | notmuch_json_show_sanitize \
-    | sed -e 's|"created": [1234567890]*|"created": 946728000|')
+    | sed -e 's|"created": [1234567890]*|"created": 946728000|g')
 expected='[[[{"id": "XXXXX",
  "match": true,
  "excluded": false,
@@ -358,6 +364,10 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["encrypted","inbox"],
+ "crypto": {"signed": {"status": [{ "status": "good", "created": 946728000, "fingerprint": "'$FINGERPRINT'",
+                                    "userid": "Notmuch Test Suite <test_suite@notmuchmail.org> (INSECURE!)"}],
+                       "encrypted": true },
+            "decrypted": {"status": "full"}},
  "headers": {"Subject": "test encrypted message 002",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
@@ -433,6 +443,7 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["inbox","signed"],
+ "crypto": {"signed": {"status": [{"errors": {"key-revoked": true}, "keyid": "'$(echo $FINGERPRINT | cut -c 25-)'", "status": "error"}]}},
  "headers": {"Subject": "test signed message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
diff --git a/test/T355-smime.sh b/test/T355-smime.sh
index be45e3b1..d947e866 100755
--- a/test/T355-smime.sh
+++ b/test/T355-smime.sh
@@ -56,8 +56,8 @@ else
 fi
 output=$(notmuch show --format=json --verify subject:"test signed message 001" \
     | notmuch_json_show_sanitize \
-    | sed -e 's|"created": [-1234567890]*|"created": 946728000|' \
-	  -e 's|"expires": [-1234567890]*|"expires": 424242424|' )
+    | sed -e 's|"created": [-1234567890]*|"created": 946728000|g' \
+	  -e 's|"expires": [-1234567890]*|"expires": 424242424|g' )
 expected='[[[{"id": "XXXXX",
  "match": true,
  "excluded": false,
@@ -65,6 +65,7 @@ expected='[[[{"id": "XXXXX",
  "timestamp": 946728000,
  "date_relative": "2000-01-01",
  "tags": ["inbox","signed"],
+ "crypto": {"signed": {"status": [{"fingerprint": "'$FINGERPRINT'", "status": "good",'$USERID' "expires": 424242424, "created": 946728000}]}},
  "headers": {"Subject": "test signed message 001",
  "From": "Notmuch Test Suite <test_suite@notmuchmail.org>",
  "To": "test_suite@notmuchmail.org",
-- 
2.20.1