1 files changed, 37 insertions, 3 deletions
diff --git a/lib/uploaded_file.rb b/lib/uploaded_file.rb
index 4a3c40f88eb..5dc85b2baea 100644
--- a/lib/uploaded_file.rb
+++ b/lib/uploaded_file.rb
@@ -1,8 +1,10 @@
 require "tempfile"
+require "tmpdir"
 require "fileutils"
 
-# Taken from: Rack::Test::UploadedFile
 class UploadedFile
+  InvalidPathError = Class.new(StandardError)
+
   # The filename, *not* including the path, of the "uploaded" file
   attr_reader :original_filename
 
@@ -12,14 +14,46 @@ class UploadedFile
   # The content type of the "uploaded" file
   attr_accessor :content_type
 
-  def initialize(path, filename, content_type = "text/plain")
-    raise "#{path} file does not exist" unless ::File.exist?(path)
+  attr_reader :remote_id
+  attr_reader :sha256
+
+  def initialize(path, filename: nil, content_type: "application/octet-stream", sha256: nil, remote_id: nil)
+    raise InvalidPathError, "#{path} file does not exist" unless ::File.exist?(path)
 
     @content_type = content_type
     @original_filename = filename || ::File.basename(path)
+    @content_type = content_type
+    @sha256 = sha256
+    @remote_id = remote_id
     @tempfile = File.new(path, 'rb')
   end
 
+  def self.from_params(params, field, upload_path)
+    unless params["#{field}.path"]
+      raise InvalidPathError, "file is invalid" if params["#{field}.remote_id"]
+
+      return
+    end
+
+    file_path = File.realpath(params["#{field}.path"])
+
+    unless self.allowed_path?(file_path, [upload_path, Dir.tmpdir].compact)
+      raise InvalidPathError, "insecure path used '#{file_path}'"
+    end
+
+    UploadedFile.new(file_path,
+      filename: params["#{field}.name"],
+      content_type: params["#{field}.type"] || 'application/octet-stream',
+      sha256: params["#{field}.sha256"],
+      remote_id: params["#{field}.remote_id"])
+  end
+
+  def self.allowed_path?(file_path, paths)
+    paths.any? do |path|
+      File.exist?(path) && file_path.start_with?(File.realpath(path))
+    end
+  end
+
   def path
     @tempfile.path
   end