Added *MimeParser tests for EOF where subpart headers should begin

jstedfast · Dec 22, 2024 · 654f318 · 654f318
1 parent e8b5545
commit 654f318
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Showing 4 changed files with 184 additions and 4 deletions.
diff --git a/MimeKit/AsyncMimeReader.cs b/MimeKit/AsyncMimeReader.cs
@@ -157,13 +157,15 @@ async Task StepHeadersAsync (CancellationToken cancellationToken)
 					left = await ReadAheadAsync (2, 0, cancellationToken).ConfigureAwait (false);
 
 				if (left == 0) {
-					if (toplevel && headerCount == 0 && headerBlockBegin == GetOffset (inputIndex)) {
+					// Note: The only way to get here is if this is the first-pass throgh this loop and we're at EOF, so headerCount should ALWAYS be 0.
+
+					if (toplevel && headerCount == 0) {
 						// EOF has been reached before any headers have been parsed for Parse[Headers,Entity,Message]Async.
 						state = MimeParserState.Eos;
 						return;
 					}
 
-					// FIXME: Should this be Content or Error?
+					// Note: This can happen if a message is truncated immediately after a boundary marker (e.g. where subpart headers would begin).
 					state = MimeParserState.Content;
 					break;
 				}

diff --git a/MimeKit/MimeReader.cs b/MimeKit/MimeReader.cs
@@ -1698,13 +1698,15 @@ unsafe void StepHeaders (byte* inbuf, CancellationToken cancellationToken)
 					left = ReadAhead (2, 0, cancellationToken);
 
 				if (left == 0) {
-					if (toplevel && headerCount == 0 && headerBlockBegin == GetOffset (inputIndex)) {
+					// Note: The only way to get here is if this is the first-pass throgh this loop and we're at EOF, so headerCount should ALWAYS be 0.
+
+					if (toplevel && headerCount == 0) {
 						// EOF has been reached before any headers have been parsed for Parse[Headers,Entity,Message].
 						state = MimeParserState.Eos;
 						return;
 					}
 
-					// FIXME: Should this be Content or Error?
+					// Note: This can happen if a message is truncated immediately after a boundary marker (e.g. where subpart headers would begin).
 					state = MimeParserState.Content;
 					break;
 				}

diff --git a/UnitTests/ExperimentalMimeParserTests.cs b/UnitTests/ExperimentalMimeParserTests.cs
@@ -941,6 +941,94 @@ This is the message body.
 			}
 		}
 
+		[Test]
+		public void TestMultipartTruncatedImmediatelyAfterBoundary ()
+		{
+			string text = @"From: [email protected]
+To: [email protected]
+Subject: test of multipart boundary w/o trailing newline
+Date: Tue, 12 Nov 2013 09:12:42 -0500
+MIME-Version: 1.0
+Message-ID: <[email protected]>
+X-Mailer: Microsoft Office Outlook 12.0
+Content-Type: multipart/mixed;
+	boundary=""----=_NextPart_000_003F_01CE98CE.6E826F90""
+
+
+------=_NextPart_000_003F_01CE98CE.6E826F90
+".Replace ("\r\n", "\n");
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text), false)) {
+				var parser = new ExperimentalMimeParser (stream, MimeFormat.Entity);
+				var message = parser.ParseMessage ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text.Replace ("\n", "\r\n")), false)) {
+				var parser = new ExperimentalMimeParser (stream, MimeFormat.Entity);
+				var message = parser.ParseMessage ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+		}
+
+		[Test]
+		public async Task TestMultipartTruncatedImmediatelyAfterBoundaryAsync ()
+		{
+			string text = @"From: [email protected]
+To: [email protected]
+Subject: test of multipart boundary w/o trailing newline
+Date: Tue, 12 Nov 2013 09:12:42 -0500
+MIME-Version: 1.0
+Message-ID: <[email protected]>
+X-Mailer: Microsoft Office Outlook 12.0
+Content-Type: multipart/mixed;
+	boundary=""----=_NextPart_000_003F_01CE98CE.6E826F90""
+
+
+------=_NextPart_000_003F_01CE98CE.6E826F90
+".Replace ("\r\n", "\n");
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text), false)) {
+				var parser = new ExperimentalMimeParser (stream, MimeFormat.Entity);
+				var message = await parser.ParseMessageAsync ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text.Replace ("\n", "\r\n")), false)) {
+				var parser = new ExperimentalMimeParser (stream, MimeFormat.Entity);
+				var message = await parser.ParseMessageAsync ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+		}
+
 		[Test]
 		public void TestMultipartBoundaryWithoutTrailingNewline ()
 		{

diff --git a/UnitTests/MimeParserTests.cs b/UnitTests/MimeParserTests.cs
@@ -933,6 +933,94 @@ This is the message body.
 			}
 		}
 
+		[Test]
+		public void TestMultipartTruncatedImmediatelyAfterBoundary ()
+		{
+			string text = @"From: [email protected]
+To: [email protected]
+Subject: test of multipart boundary w/o trailing newline
+Date: Tue, 12 Nov 2013 09:12:42 -0500
+MIME-Version: 1.0
+Message-ID: <[email protected]>
+X-Mailer: Microsoft Office Outlook 12.0
+Content-Type: multipart/mixed;
+	boundary=""----=_NextPart_000_003F_01CE98CE.6E826F90""
+
+
+------=_NextPart_000_003F_01CE98CE.6E826F90
+".Replace ("\r\n", "\n");
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text), false)) {
+				var parser = new MimeParser (stream, MimeFormat.Entity);
+				var message = parser.ParseMessage ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text.Replace ("\n", "\r\n")), false)) {
+				var parser = new MimeParser (stream, MimeFormat.Entity);
+				var message = parser.ParseMessage ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+		}
+
+		[Test]
+		public async Task TestMultipartTruncatedImmediatelyAfterBoundaryAsync ()
+		{
+			string text = @"From: [email protected]
+To: [email protected]
+Subject: test of multipart boundary w/o trailing newline
+Date: Tue, 12 Nov 2013 09:12:42 -0500
+MIME-Version: 1.0
+Message-ID: <[email protected]>
+X-Mailer: Microsoft Office Outlook 12.0
+Content-Type: multipart/mixed;
+	boundary=""----=_NextPart_000_003F_01CE98CE.6E826F90""
+
+
+------=_NextPart_000_003F_01CE98CE.6E826F90
+".Replace ("\r\n", "\n");
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text), false)) {
+				var parser = new MimeParser (stream, MimeFormat.Entity);
+				var message = await parser.ParseMessageAsync ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+
+			using (var stream = new MemoryStream (Encoding.ASCII.GetBytes (text.Replace ("\n", "\r\n")), false)) {
+				var parser = new MimeParser (stream, MimeFormat.Entity);
+				var message = await parser.ParseMessageAsync ();
+
+				Assert.That (message.Body, Is.InstanceOf<Multipart> (), "Expected top-level to be a multipart");
+				var multipart = (Multipart) message.Body;
+				Assert.That (multipart.Count, Is.EqualTo (1));
+				Assert.That (multipart[0], Is.InstanceOf<TextPart> (), "Expected first child of the multipart to be text/plain");
+				var body = (TextPart) multipart[0];
+
+				Assert.That (body.Text, Is.EqualTo (string.Empty));
+			}
+		}
+
 		[Test]
 		public void TestMultipartBoundaryWithoutTrailingNewline ()
 		{