azure: handle encryption headers and azure InvalidMetadata error (#4893)

Previously minio gateway returns invalid bucket name error for invalid
meta data.  This is fixed by returning BadRequest with 'Unsupported
metadata' in response.

Fixes #4891

cmd/api-errors.go

@@ -117,6 +117,7 @@ const (
 	ErrNotSupported
 	ErrBucketAlreadyExists
 	ErrMetadataTooLarge
+	ErrUnsupportedMetadata
 	// Add new error codes here.
 
 	// Bucket notification related errors.
@@ -654,6 +655,11 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "Your metadata headers exceed the maximum allowed metadata size.",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
+	ErrUnsupportedMetadata: {
+		Code:           "InvalidArgument",
+		Description:    "Your metadata headers are not supported.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	// Add your error structure here.
 }
 
@@ -750,6 +756,8 @@ func toAPIErrorCode(err error) (apiErr APIErrorCode) {
 		apiErr = ErrNoSuchBucketPolicy
 	case PartTooBig:
 		apiErr = ErrEntityTooLarge
+	case UnsupportedMetadata:
+		apiErr = ErrUnsupportedMetadata
 	default:
 		apiErr = ErrInternalError
 	}

cmd/gateway-azure.go

@@ -45,9 +45,18 @@ const azureBlockSize = 100 * humanize.MiByte
 // Also replaces X-Amz-Meta prefix with X-Ms-Meta as Azure expects user
 // defined metadata to have X-Ms-Meta prefix.
 func s3ToAzureHeaders(headers map[string]string) (newHeaders map[string]string) {
+	gatewayHeaders := map[string]string{
+		"X-Amz-Meta-X-Amz-Key":     "X-Amz-Meta-x_minio_key",
+		"X-Amz-Meta-X-Amz-Matdesc": "X-Amz-Meta-x_minio_matdesc",
+		"X-Amz-Meta-X-Amz-Iv":      "X-Amz-Meta-x_minio_iv",
+	}
+
 	newHeaders = make(map[string]string)
 	for k, v := range headers {
 		k = http.CanonicalHeaderKey(k)
+		if nk, ok := gatewayHeaders[k]; ok {
+			k = nk
+		}
 		if strings.HasPrefix(k, "X-Amz-Meta") {
 			k = strings.Replace(k, "X-Amz-Meta", "X-Ms-Meta", -1)
 		}
@@ -59,10 +68,19 @@ func s3ToAzureHeaders(headers map[string]string) (newHeaders map[string]string)
 // Prefix user metadata with "X-Amz-Meta-".
 // client.GetBlobMetadata() already strips "X-Ms-Meta-"
 func azureToS3Metadata(meta map[string]string) (newMeta map[string]string) {
+	gatewayHeaders := map[string]string{
+		"X-Amz-Meta-x_minio_key":     "X-Amz-Meta-X-Amz-Key",
+		"X-Amz-Meta-x_minio_matdesc": "X-Amz-Meta-X-Amz-Matdesc",
+		"X-Amz-Meta-x_minio_iv":      "X-Amz-Meta-X-Amz-Iv",
+	}
+
 	newMeta = make(map[string]string)
 
 	for k, v := range meta {
 		k = "X-Amz-Meta-" + k
+		if nk, ok := gatewayHeaders[k]; ok {
+			k = nk
+		}
 		newMeta[k] = v
 	}
 	return newMeta
@@ -145,6 +163,8 @@ func azureToObjectError(err error, params ...string) error {
 		err = BucketNameInvalid{Bucket: bucket}
 	case "RequestBodyTooLarge":
 		err = PartTooBig{}
+	case "InvalidMetadata":
+		err = UnsupportedMetadata{}
 	default:
 		switch azureErr.StatusCode {
 		case http.StatusNotFound:

cmd/gateway-azure_test.go

@@ -48,11 +48,17 @@ func TestS3ToAzureHeaders(t *testing.T) {
 		"accept-encoding":          "gzip",
 		"content-encoding":         "gzip",
 		"X-Amz-Meta-Hdr":           "value",
+		"X-Amz-Meta-X-Amz-Key":     "hu3ZSqtqwn+aL4V2VhAeov4i+bG3KyCtRMSXQFRHXOk=",
+		"X-Amz-Meta-X-Amz-Matdesc": "{}",
+		"X-Amz-Meta-X-Amz-Iv":      "eWmyryl8kq+EVnnsE7jpOg==",
 	}
 	expectedHeaders := map[string]string{
 		"Accept-Encoding":           "gzip",
 		"Content-Encoding":          "gzip",
 		"X-Ms-Meta-Hdr":             "value",
+		"X-Ms-Meta-x_minio_key":     "hu3ZSqtqwn+aL4V2VhAeov4i+bG3KyCtRMSXQFRHXOk=",
+		"X-Ms-Meta-x_minio_matdesc": "{}",
+		"X-Ms-Meta-x_minio_iv":      "eWmyryl8kq+EVnnsE7jpOg==",
 	}
 	actualHeaders := s3ToAzureHeaders(headers)
 	if !reflect.DeepEqual(actualHeaders, expectedHeaders) {
@@ -65,9 +71,15 @@ func TestAzureToS3Metadata(t *testing.T) {
 	// as azureToS3Metadata() just adds a prefix.
 	metadata := map[string]string{
 		"First-Name":      "myname",
+		"x_minio_key":     "hu3ZSqtqwn+aL4V2VhAeov4i+bG3KyCtRMSXQFRHXOk=",
+		"x_minio_matdesc": "{}",
+		"x_minio_iv":      "eWmyryl8kq+EVnnsE7jpOg==",
 	}
 	expectedMeta := map[string]string{
 		"X-Amz-Meta-First-Name":    "myname",
+		"X-Amz-Meta-X-Amz-Key":     "hu3ZSqtqwn+aL4V2VhAeov4i+bG3KyCtRMSXQFRHXOk=",
+		"X-Amz-Meta-X-Amz-Matdesc": "{}",
+		"X-Amz-Meta-X-Amz-Iv":      "eWmyryl8kq+EVnnsE7jpOg==",
 	}
 	actualMeta := azureToS3Metadata(metadata)
 	if !reflect.DeepEqual(actualMeta, expectedMeta) {

cmd/object-api-errors.go

@@ -387,6 +387,13 @@ func (e PolicyNotFound) Error() string {
 	return "Policy not found"
 }
 
+// UnsupportedMetadata - unsupported metadata
+type UnsupportedMetadata struct{}
+
+func (e UnsupportedMetadata) Error() string {
+	return "Unsupported headers in Metadata"
+}
+
 // Check if error type is IncompleteBody.
 func isErrIncompleteBody(err error) bool {
 	err = errorCause(err)