S3 API: unsigned streaming (no cred) but chunks contain signatures (#7118)

* This handles the case where we have unsigned streaming (no cred) but chunks contain signatures

* Update chunked_reader_v4.go

* address comments

weed/s3api/chunked_bug_reproduction_test.go

@@ -0,0 +1,55 @@
+package s3api
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"testing"
+
+	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
+)
+
+// TestChunkedEncodingMixedFormat tests the fix for GitHub issue #6847
+// where AWS SDKs send mixed format: unsigned streaming headers but signed chunk data
+func TestChunkedEncodingMixedFormat(t *testing.T) {
+	expectedContent := "hello world\n"
+
+	// Create the problematic mixed format payload:
+	// - Unsigned streaming headers (STREAMING-UNSIGNED-PAYLOAD-TRAILER)
+	// - But chunk data contains chunk-signature headers
+	mixedFormatPayload := "c;chunk-signature=347f6c62acd95b7c6ae18648776024a9e8cd6151184a5e777ea8e1d9b4e45b3c\r\n" +
+		"hello world\n\r\n" +
+		"0;chunk-signature=1a99b7790b8db0f4bfc048c8802056c3179d561e40c073167e79db5f1a6af4b2\r\n" +
+		"x-amz-checksum-crc32:rwg7LQ==\r\n" +
+		"\r\n"
+
+	// Create HTTP request with unsigned streaming headers
+	req, _ := http.NewRequest("PUT", "/test-bucket/test-object", bytes.NewReader([]byte(mixedFormatPayload)))
+	req.Header.Set("x-amz-content-sha256", "STREAMING-UNSIGNED-PAYLOAD-TRAILER")
+	req.Header.Set("x-amz-trailer", "x-amz-checksum-crc32")
+
+	// Process through SeaweedFS chunked reader
+	iam := setupTestIAM()
+	reader, errCode := iam.newChunkedReader(req)
+
+	if errCode != s3err.ErrNone {
+		t.Fatalf("Failed to create chunked reader: %v", errCode)
+	}
+
+	// Read the content
+	actualContent, err := io.ReadAll(reader)
+	if err != nil {
+		t.Fatalf("Failed to read content: %v", err)
+	}
+
+	// Should correctly extract just the content, ignoring chunk signatures
+	if string(actualContent) != expectedContent {
+		t.Errorf("Mixed format handling failed. Expected: %q, Got: %q", expectedContent, string(actualContent))
+	}
+}
+
+// setupTestIAM creates a test IAM instance using the same pattern as existing tests
+func setupTestIAM() *IdentityAccessManagement {
+	iam := &IdentityAccessManagement{}
+	return iam
+}

weed/s3api/chunked_reader_v4.go

@@ -440,18 +440,35 @@ func (cr *s3ChunkedReader) Read(buf []byte) (n int, err error) {
 				continue
 			}
 		case verifyChunk:
-			// Calculate the hashed chunk.
-			hashedChunk := hex.EncodeToString(cr.chunkSHA256Writer.Sum(nil))
-			// Calculate the chunk signature.
-			newSignature := cr.getChunkSignature(hashedChunk)
-			if !compareSignatureV4(cr.chunkSignature, newSignature) {
-				// Chunk signature doesn't match we return signature does not match.
-				cr.err = errors.New(s3err.ErrMsgChunkSignatureMismatch)
-				return 0, cr.err
+			// Check if we have credentials for signature verification
+			// This handles the case where we have unsigned streaming (no cred) but chunks contain signatures
+			//
+			// BUG FIX for GitHub issue #6847:
+			// Some AWS SDK versions (Java 3.7.412+, .NET 4.0.0-preview.6+) send mixed format:
+			// - HTTP headers indicate unsigned streaming (STREAMING-UNSIGNED-PAYLOAD-TRAILER)
+			// - But chunk data contains chunk-signature headers (normally only for signed streaming)
+			// This causes a nil pointer dereference when trying to verify signatures without credentials
+			if cr.cred != nil {
+				// Normal signed streaming - verify the chunk signature
+				// Calculate the hashed chunk.
+				hashedChunk := hex.EncodeToString(cr.chunkSHA256Writer.Sum(nil))
+				// Calculate the chunk signature.
+				newSignature := cr.getChunkSignature(hashedChunk)
+				if !compareSignatureV4(cr.chunkSignature, newSignature) {
+					// Chunk signature doesn't match we return signature does not match.
+					cr.err = errors.New(s3err.ErrMsgChunkSignatureMismatch)
+					return 0, cr.err
+				}
+				// Newly calculated signature becomes the seed for the next chunk
+				// this follows the chaining.
+				cr.seedSignature = newSignature
+			} else {
+				// For unsigned streaming, we should not verify chunk signatures even if they are present
+				// This fixes the bug where AWS SDKs send chunk signatures with unsigned streaming headers
+				glog.V(3).Infof("Skipping chunk signature verification for unsigned streaming")
 			}
-			// Newly calculated signature becomes the seed for the next chunk
-			// this follows the chaining.
-			cr.seedSignature = newSignature
+
+			// Common cleanup and state transition for both signed and unsigned streaming
 			cr.chunkSHA256Writer.Reset()
 			if cr.lastChunk {
 				cr.state = eofChunk
@@ -513,9 +530,10 @@ func readChunkLine(b *bufio.Reader) ([]byte, error) {
 	if err != nil {
 		// We always know when EOF is coming.
 		// If the caller asked for a line, there should be a line.
-		if err == io.EOF {
+		switch err {
+		case io.EOF:
 			err = io.ErrUnexpectedEOF
-		} else if err == bufio.ErrBufferFull {
+		case bufio.ErrBufferFull:
 			err = errLineTooLong
 		}
 		return nil, err