1 files changed, 16 insertions, 8 deletions
diff --git a/activestorage/lib/active_storage/service/gcs_service.rb b/activestorage/lib/active_storage/service/gcs_service.rb
index 18c0f14cfc..e2590aa35d 100644
--- a/activestorage/lib/active_storage/service/gcs_service.rb
+++ b/activestorage/lib/active_storage/service/gcs_service.rb
@@ -11,16 +11,15 @@ module ActiveStorage
       @config = config
     end
 
-    def upload(key, io, checksum: nil)
+    def upload(key, io, checksum: nil, content_type: nil, disposition: nil, filename: nil)
       instrument :upload, key: key, checksum: checksum do
         begin
-          # The official GCS client library doesn't allow us to create a file with no Content-Type metadata.
-          # We need the file we create to have no Content-Type so we can control it via the response-content-type
-          # param in signed URLs. Workaround: let the GCS client create the file with an inferred
-          # Content-Type (usually "application/octet-stream") then clear it.
-          bucket.create_file(io, key, md5: checksum).update do |file|
-            file.content_type = nil
-          end
+          # GCS's signed URLs don't include params such as response-content-type response-content_disposition
+          # in the signature, which means an attacker can modify them and bypass our effort to force these to
+          # binary and attachment when the file's content type requires it. The only way to force them is to
+          # store them as object's metadata.
+          content_disposition = content_disposition_with(type: disposition, filename: filename) if disposition && filename
+          bucket.create_file(io, key, md5: checksum, content_type: content_type, content_disposition: content_disposition)
         rescue Google::Cloud::InvalidArgumentError
           raise ActiveStorage::IntegrityError
         end
@@ -43,6 +42,15 @@ module ActiveStorage
       end
     end
 
+    def update_metadata(key, content_type:, disposition: nil, filename: nil)
+      instrument :update_metadata, key: key, content_type: content_type, disposition: disposition do
+        file_for(key).update do |file|
+          file.content_type = content_type
+          file.content_disposition = content_disposition_with(type: disposition, filename: filename) if disposition && filename
+        end
+      end
+    end
+
     def download_chunk(key, range)
       instrument :download_chunk, key: key, range: range do
         begin