Remove max limit on event stream messages (#3009)

* Remove max limit on event stream messages

* Add changelog

.changelog/cd702d00aeb046daad4091fd8a26a0b4.json

@@ -0,0 +1,8 @@
+{
+    "id": "cd702d00-aeb0-46da-ad40-91fd8a26a0b4",
+    "type": "bugfix",
+    "description": "Remove max limit on event stream messages",
+    "modules": [
+        "aws/protocol/eventstream"
+    ]
+}

aws/protocol/eventstream/decode_test.go

@@ -3,6 +3,7 @@ package eventstream
 import (
 	"bytes"
 	"encoding/hex"
+	"errors"
 	"io/ioutil"
 	"os"
 	"reflect"
@@ -141,6 +142,19 @@ func TestDecoder_DecodeMultipleMessages(t *testing.T) {
 	}
 }
 
+func TestDecodeLimits(t *testing.T) {
+	l := 25 * 1024 * 1024                    // Previously we failed if message was set to >16 MB
+	payload := bytes.Repeat([]byte{0x01}, l) // if set to just 0, message will be read as having 0 size.
+	buffer := bytes.NewBuffer(payload)
+	_, err := NewDecoder().Decode(buffer, nil)
+	if err == nil {
+		t.Fatalf("expect error since message is not properly encoded, got none")
+	}
+	if errors.As(err, &LengthError{}) {
+		t.Fatalf("expect error not being a length error, got %v", err)
+	}
+}
+
 func BenchmarkDecode(b *testing.B) {
 	r := bytes.NewReader(testEncodedMsg)
 	decoder := NewDecoder()

aws/protocol/eventstream/encode_test.go

@@ -3,6 +3,7 @@ package eventstream
 import (
 	"bytes"
 	"encoding/hex"
+	"io"
 	"reflect"
 	"testing"
 )
@@ -48,3 +49,27 @@ func BenchmarkEncode(b *testing.B) {
 		}
 	}
 }
+
+func TestEncoder_Limits(t *testing.T) {
+	l := 25 * 1024 * 1024 // Previously we failed if message was set to >16 MB
+	payload := make([]byte, l)
+	encoder := NewEncoder()
+	err := encoder.Encode(io.Discard, Message{Payload: payload})
+	if err != nil {
+		t.Fatalf("Expected encoder being able to encode %d size, failed with %v", l, err)
+	}
+
+	h := Header{
+		Name: "event-id", Value: Int16Value(123),
+	}
+
+	headers := make(Headers, 0, 10_000) // Previously we failed if headers size was above a certain size
+	for i := 0; i < 10_000; i++ {
+		headers = append(headers, h)
+	}
+
+	err = encoder.Encode(io.Discard, Message{Headers: headers})
+	if err != nil {
+		t.Fatalf("Expected encoder being able to encode %d size, failed with %v", l, err)
+	}
+}

aws/protocol/eventstream/message.go

@@ -10,9 +10,6 @@ const preludeLen = 8
 const preludeCRCLen = 4
 const msgCRCLen = 4
 const minMsgLen = preludeLen + preludeCRCLen + msgCRCLen
-const maxPayloadLen = 1024 * 1024 * 16 // 16MB
-const maxHeadersLen = 1024 * 128       // 128KB
-const maxMsgLen = minMsgLen + maxHeadersLen + maxPayloadLen
 
 var crc32IEEETable = crc32.MakeTable(crc32.IEEE)
 
@@ -82,28 +79,13 @@ func (p messagePrelude) PayloadLen() uint32 {
 }
 
 func (p messagePrelude) ValidateLens() error {
-	if p.Length == 0 || p.Length > maxMsgLen {
+	if p.Length == 0 {
 		return LengthError{
 			Part: "message prelude",
-			Want: maxMsgLen,
+			Want: minMsgLen,
 			Have: int(p.Length),
 		}
 	}
-	if p.HeadersLen > maxHeadersLen {
-		return LengthError{
-			Part: "message headers",
-			Want: maxHeadersLen,
-			Have: int(p.HeadersLen),
-		}
-	}
-	if payloadLen := p.PayloadLen(); payloadLen > maxPayloadLen {
-		return LengthError{
-			Part: "message payload",
-			Want: maxPayloadLen,
-			Have: int(payloadLen),
-		}
-	}
-
 	return nil
 }