fix: detect imip messages from outlook.com

Adjust the parsing logic in MessageMapper to correctly detect iMIP messages in flat email structures where the text/calendar part is not wrapped in multipart/alternative.

Signed-off-by: Daniel Kesselberg <[email protected]>

REUSE.toml

@@ -107,6 +107,12 @@ precedence = "aggregate"
 SPDX-FileCopyrightText = "2024 Nextcloud GmbH and Nextcloud contributors"
 SPDX-License-Identifier = "AGPL-3.0-or-later"
 
+[[annotations]]
+path = ["tests/data/imip/*"]
+precedence = "aggregate"
+SPDX-FileCopyrightText = "2025 Nextcloud GmbH and Nextcloud contributors"
+SPDX-License-Identifier = "AGPL-3.0-or-later"
+
 [[annotations]]
 path = ".github/CODEOWNERS"
 precedence = "aggregate"

lib/IMAP/MessageMapper.php

@@ -888,15 +888,13 @@ public function getBodyStructureData(Horde_Imap_Client_Socket $client,
 			$structure = $fetchData->getStructure();
 
 			/** @var Horde_Mime_Part $part */
-			foreach ($structure->getParts() as $part) {
+			foreach ($structure->partIterator() as $part) {
 				if ($part->isAttachment()) {
 					$hasAttachments = true;
 				}
-				$bodyParts = $part->getParts();
-				/** @var Horde_Mime_Part $bodyPart */
-				foreach ($bodyParts as $bodyPart) {
-					$contentParameters = $bodyPart->getAllContentTypeParameters();
-					if ($bodyPart->getType() === 'text/calendar' && isset($contentParameters['method'])) {
+
+				if ($part->getType() === 'text/calendar') {
+					if ($part->getContentTypeParameter('method') !== null) {
 						$isImipMessage = true;
 					}
 				}

tests/Unit/IMAP/MessageMapperTest.php

@@ -593,4 +593,45 @@ public function testGetFlaggedSearchResultUnexpectedStructure() {
 		$result = $this->mapper->getFlagged($imapClient, $mailbox, $flag);
 		$this->assertEquals($result, []);
 	}
+
+	/**
+	 * This test ensures that we correctly identify iMIP messages from various
+	 * sources as valid iMIP messages. The test cases are based on original
+	 * iMIP messages from different vendors. The focus is on the MIME message
+	 * structure and verifying that we traverse the MIME tree properly.
+	 *
+	 * @dataProvider isImipMessageProvider
+	 */
+	public function testGetBodyStructureIsImipMessage(string $filename, bool $expected): void {
+		$text = file_get_contents(__DIR__ . '/../../data/imip/' . $filename . '.txt');
+		$part = \Horde_Mime_Part::parseMessage($text);
+
+		$fetchData = new Horde_Imap_Client_Data_Fetch();
+		$fetchData->setStructure($part);
+		$fetchData->setUid(100);
+
+		$fetchResult = new Horde_Imap_Client_Fetch_Results();
+		$fetchResult[0] = $fetchData;
+
+		$imapClient = $this->createMock(Horde_Imap_Client_Socket::class);
+		$imapClient->method('fetch')
+			->willReturn($fetchResult);
+
+		$data = $this->mapper->getBodyStructureData(
+			$imapClient,
+			'INBOX',
+			[100],
+			'[email protected]'
+		);
+
+		$this->assertCount(1, $data);
+		$this->assertEquals($expected, $data[0]->isImipMessage());
+	}
+
+	public function isImipMessageProvider(): array {
+		return [
+			'google request' => ['request_google', true],
+			'outlook.com request' => ['request_outlook_com', true],
+		];
+	}
 }

tests/data/imip/request_google.txt

@@ -0,0 +1,74 @@
+MIME-Version: 1.0
+Message-ID: <[email protected]>
+Date: Thu, 06 Feb 2025 16:21:41 +0000
+From: [email protected]
+To: [email protected], [email protected]
+Content-Type: multipart/mixed; boundary="f2d8330e8efc4039bd8073c70ec6cf24"
+Subject: Invitation: Imip Testing @ Thu Feb 20, 2025 7pm - 8pm
+	(CET) ([email protected])
+
+--f2d8330e8efc4039bd8073c70ec6cf24
+Content-Type: multipart/alternative; boundary="f55a70234308486098b936b62a6d5e33"
+
+--f55a70234308486098b936b62a6d5e33
+Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes
+Content-Transfer-Encoding: base64
+
+SW1pcCBUZXN0aW5nICh0ZXh0L3BsYWluKQo=
+--f55a70234308486098b936b62a6d5e33
+Content-Type: text/calendar; charset="UTF-8"; method=REQUEST
+Content-Transfer-Encoding: 7bit
+
+BEGIN:VCALENDAR
+PRODID:-//Google Inc//Google Calendar 70.9054//EN
+VERSION:2.0
+CALSCALE:GREGORIAN
+METHOD:REQUEST
+BEGIN:VTIMEZONE
+TZID:Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:GMT+2
+DTSTART:19700329T020000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:GMT+1
+DTSTART:19701025T030000
+RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTART;TZID=Europe/Berlin:20250220T190000
+DTEND;TZID=Europe/Berlin:20250220T200000
+DTSTAMP:20250206T162141Z
+ORGANIZER;[email protected]:mailto:[email protected]
+UID:[email protected]
+ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=
+ TRUE;[email protected];X-NUM-GUESTS=0:mailto:[email protected]
+ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;RSVP=TRUE
+ ;[email protected];X-NUM-GUESTS=0:mailto:[email protected]
+ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=
+ TRUE;[email protected];X-NUM-GUESTS=0:mailto:[email protected]
+CREATED:20250206T162140Z
+DESCRIPTION:
+LAST-MODIFIED:20250206T162140Z
+LOCATION:
+SEQUENCE:0
+STATUS:CONFIRMED
+SUMMARY:Imip Testing
+TRANSP:OPAQUE
+BEGIN:VALARM
+ACTION:DISPLAY
+DESCRIPTION:This is an event reminder
+TRIGGER:-P0DT0H30M0S
+END:VALARM
+END:VEVENT
+END:VCALENDAR
+
+--f55a70234308486098b936b62a6d5e33--
+--f2d8330e8efc4039bd8073c70ec6cf24--

tests/data/imip/request_outlook_com.txt

@@ -0,0 +1,53 @@
+From: [email protected]
+To: [email protected], [email protected]
+Date: Thu, 6 Feb 2025 10:26:13 +0000
+Message-ID: <[email protected]>
+Accept-Language: en-US, de-DE
+Content-Language: en-US
+Content-Type: multipart/alternative;
+	boundary="a6ccc118fe8d4081837903c834923d7a"
+MIME-Version: 1.0
+Subject: Imip Testing
+
+--a6ccc118fe8d4081837903c834923d7a
+Content-Type: text/plain; charset="iso-8859-1"
+Content-Transfer-Encoding: quoted-printable
+
+
+
+--a6ccc118fe8d4081837903c834923d7a
+Content-Type: text/html; charset="iso-8859-1"
+Content-Transfer-Encoding: quoted-printable
+
+
+--a6ccc118fe8d4081837903c834923d7a
+Content-Type: text/calendar; charset="utf-8"; method=REQUEST
+Content-Transfer-Encoding: base64
+
+QkVHSU46VkNBTEVOREFSCk1FVEhPRDpSRVFVRVNUClBST0RJRDpNaWNyb3NvZnQgRXhjaGFuZ2Ug
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+
+--a6ccc118fe8d4081837903c834923d7a--