Reject unsupported aws-chunked uploads

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

api/api.go

@@ -41,6 +41,7 @@ const (
 	maxXMLBodyBytes         int64 = 1 << 20
 	maxDeleteObjects              = 1000
 	maxObjectKeyBytes             = 1024
+	maxAWSChunkedLineBytes        = 8 << 10
 	serverReadHeaderTimeout       = 5 * time.Second
 	serverReadTimeout             = 60 * time.Second
 	serverWriteTimeout            = 120 * time.Second
@@ -387,6 +388,10 @@ func (h *Handler) handlePutObject(w http.ResponseWriter, r *http.Request) {
 
 		bodyReader := io.Reader(r.Body)
 		var decodeStream io.ReadCloser
+		if hasUnsupportedAWSChunkedPayload(r) {
+			writeS3Error(w, r, s3ErrInvalidArgument, r.URL.Path)
+			return
+		}
 		if shouldDecodeAWSChunkedPayload(r) {
 			decodeStream = newAWSChunkedDecodingReader(r.Body)
 			defer decodeStream.Close()
@@ -461,6 +466,10 @@ func (h *Handler) handlePutObject(w http.ResponseWriter, r *http.Request) {
 
 	bodyReader := io.Reader(r.Body)
 	var decodeStream io.ReadCloser
+	if hasUnsupportedAWSChunkedPayload(r) {
+		writeS3Error(w, r, s3ErrInvalidArgument, r.URL.Path)
+		return
+	}
 	if shouldDecodeAWSChunkedPayload(r) {
 		decodeStream = newAWSChunkedDecodingReader(r.Body)
 		defer decodeStream.Close()
@@ -516,17 +525,18 @@ func (h *Handler) handleListMultipartParts(w http.ResponseWriter, r *http.Reques
 }
 
 func shouldDecodeAWSChunkedPayload(r *http.Request) bool {
-	contentEncoding := strings.ToLower(r.Header.Get("Content-Encoding"))
-	if strings.Contains(contentEncoding, "aws-chunked") {
-		return true
-	}
 	signingMode := strings.ToLower(r.Header.Get("x-amz-content-sha256"))
-	if strings.HasPrefix(signingMode, "streaming-aws4-hmac-sha256-payload") {
-		return true
-	}
 	return strings.HasPrefix(signingMode, "streaming-unsigned-payload")
 }
 
+func hasUnsupportedAWSChunkedPayload(r *http.Request) bool {
+	contentEncoding := strings.ToLower(r.Header.Get("Content-Encoding"))
+	if !strings.Contains(contentEncoding, "aws-chunked") {
+		return false
+	}
+	return !shouldDecodeAWSChunkedPayload(r)
+}
+
 func newAWSChunkedDecodingReader(src io.Reader) io.ReadCloser {
 	probedReader, isAWSChunked := probeAWSChunkedPayload(src)
 	if !isAWSChunked {
@@ -545,9 +555,12 @@ func newAWSChunkedDecodingReader(src io.Reader) io.ReadCloser {
 }
 
 func probeAWSChunkedPayload(src io.Reader) (io.Reader, bool) {
-	reader := bufio.NewReaderSize(src, 512)
+	reader := bufio.NewReaderSize(src, maxAWSChunkedLineBytes)
 	headerLine, err := reader.ReadSlice('\n')
 	replay := io.MultiReader(bytes.NewReader(headerLine), reader)
+	if errors.Is(err, bufio.ErrBufferFull) {
+		return replay, true
+	}
 	if err != nil {
 		return replay, false
 	}
@@ -569,9 +582,9 @@ func probeAWSChunkedPayload(src io.Reader) (io.Reader, bool) {
 }
 
 func decodeAWSChunkedPayload(src io.Reader, dst io.Writer) error {
-	reader := bufio.NewReader(src)
+	reader := bufio.NewReaderSize(src, maxAWSChunkedLineBytes)
 	for {
-		headerLine, err := reader.ReadString('\n')
+		headerLine, err := readAWSChunkedLine(reader)
 		if err != nil {
 			return err
 		}
@@ -588,6 +601,17 @@ func decodeAWSChunkedPayload(src io.Reader, dst io.Writer) error {
 		if chunkSize < 0 {
 			return fmt.Errorf("invalid aws-chunked size: %d", chunkSize)
 		}
+		if chunkSize == 0 {
+			for {
+				line, err := readAWSChunkedLine(reader)
+				if err != nil {
+					return err
+				}
+				if line == "\r\n" || line == "\n" {
+					return nil
+				}
+			}
+		}
 		if chunkSize > 0 {
 			if _, err := io.CopyN(dst, reader, chunkSize); err != nil {
 				return err
@@ -601,19 +625,18 @@ func decodeAWSChunkedPayload(src io.Reader, dst io.Writer) error {
 		if crlf[0] != '\r' || crlf[1] != '\n' {
 			return errors.New("invalid aws-chunked payload terminator")
 		}
+	}
+}
 
-		if chunkSize == 0 {
+func readAWSChunkedLine(reader *bufio.Reader) (string, error) {
-			for {
+	line, err := reader.ReadSlice('\n')
-				line, err := reader.ReadString('\n')
+	if errors.Is(err, bufio.ErrBufferFull) {
-				if err != nil {
+		return "", service.ErrEntityTooLarge
-					return err
-				}
-				if line == "\r\n" || line == "\n" {
-					return nil
-				}
-			}
 	}
+	if len(line) > maxAWSChunkedLineBytes {
+		return "", service.ErrEntityTooLarge
 	}
+	return string(line), err
 }
 
 func ifNoneMatchPreconditionFailed(headerValue, etag string) bool {

api/aws_chunked_test.go

@@ -1,10 +1,14 @@
 package api
 
 import (
+	"errors"
 	"io"
 	"net/http"
+	"net/http/httptest"
 	"strings"
 	"testing"
+
+	"fs/service"
 )
 
 func TestShouldDecodeAWSChunkedPayloadUnsignedTrailerMode(t *testing.T) {
@@ -20,6 +24,45 @@ func TestShouldDecodeAWSChunkedPayloadUnsignedTrailerMode(t *testing.T) {
 	}
 }
 
+func TestUnsupportedAWSChunkedContentEncodingWithoutStreamingMode(t *testing.T) {
+	t.Parallel()
+
+	req, err := http.NewRequest(http.MethodPut, "http://example.com/b/k", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Content-Encoding", "aws-chunked")
+	req.Header.Set("x-amz-content-sha256", "UNSIGNED-PAYLOAD")
+
+	if !hasUnsupportedAWSChunkedPayload(req) {
+		t.Fatalf("expected aws-chunked content encoding without streaming mode to be unsupported")
+	}
+	if shouldDecodeAWSChunkedPayload(req) {
+		t.Fatalf("non-streaming aws-chunked content encoding must not trigger decoding")
+	}
+}
+
+func TestPutObjectRejectsUnsignedAWSChunkedContentEncoding(t *testing.T) {
+	handler, svc := newUploadLimitHandler(t, 1024)
+	if err := svc.CreateBucket("test-bucket"); err != nil {
+		t.Fatalf("CreateBucket: %v", err)
+	}
+
+	req := httptest.NewRequest(http.MethodPut, "/test-bucket/object.txt", strings.NewReader("4\r\nWiki\r\n0\r\n\r\n"))
+	req.Header.Set("Content-Encoding", "aws-chunked")
+	req.Header.Set("x-amz-content-sha256", "UNSIGNED-PAYLOAD")
+	rec := httptest.NewRecorder()
+
+	handler.router.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusBadRequest {
+		t.Fatalf("status = %d, want %d body=%s", rec.Code, http.StatusBadRequest, rec.Body.String())
+	}
+	if !strings.Contains(rec.Body.String(), "InvalidArgument") {
+		t.Fatalf("expected InvalidArgument response, body=%s", rec.Body.String())
+	}
+}
+
 func TestAWSChunkedReaderPassThroughForPlainPayload(t *testing.T) {
 	t.Parallel()
 
@@ -43,7 +86,6 @@ func TestAWSChunkedReaderDecodesChunkedPayload(t *testing.T) {
 		"4\r\nWiki\r\n" +
 		"5\r\npedia\r\n" +
 		"0\r\n" +
-		"\r\n" +
 		"x-amz-checksum-crc32:xxxx\r\n" +
 		"\r\n"
 
@@ -58,3 +100,16 @@ func TestAWSChunkedReaderDecodesChunkedPayload(t *testing.T) {
 		t.Fatalf("decoded payload mismatch: got %q want %q", string(out), "Wikipedia")
 	}
 }
+
+func TestAWSChunkedReaderRejectsOversizedChunkHeader(t *testing.T) {
+	t.Parallel()
+
+	encoded := strings.Repeat("f", maxAWSChunkedLineBytes+1) + "\n"
+	reader := newAWSChunkedDecodingReader(strings.NewReader(encoded))
+	defer reader.Close()
+
+	_, err := io.ReadAll(reader)
+	if !errors.Is(err, service.ErrEntityTooLarge) {
+		t.Fatalf("read error = %v, want ErrEntityTooLarge", err)
+	}
+}