Remove the use of String#% when formatting durations in log messages

This avoids potential format string vulnerabilities where user-provided
data is interpolated into the log message before String#% is called.

3 files changed, 12 insertions, 9 deletions

diff --git a/actionmailer/lib/action_mailer/log_subscriber.rb b/actionmailer/lib/action_mailer/log_subscriber.rb
index 7ba57b19e0..4f4e21e0eb 100644
--- a/actionmailer/lib/action_mailer/log_subscriber.rb
+++ b/actionmailer/lib/action_mailer/log_subscriber.rb
@@ -4,12 +4,12 @@ module ActionMailer
   class LogSubscriber < ActiveSupport::LogSubscriber
     def deliver(event)
       recipients = Array.wrap(event.payload[:to]).join(', ')
-      info("\nSent mail to #{recipients} (%1.fms)" % event.duration)
+      info("\nSent mail to #{recipients} (#{format_duration(event.duration)})")
       debug(event.payload[:mail])
     end
 
     def receive(event)
-      info("\nReceived mail (%.1fms)" % event.duration)
+      info("\nReceived mail (#{format_duration(event.duration)})")
       debug(event.payload[:mail])
     end
 
@@ -19,4 +19,4 @@ module ActionMailer
   end
 end
 
-ActionMailer::LogSubscriber.attach_to :action_mailer
\ No newline at end of file
+ActionMailer::LogSubscriber.attach_to :action_mailer
diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
index 194f26aefc..f2545ef2cd 100644
--- a/actionpack/lib/action_controller/log_subscriber.rb
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -23,7 +23,7 @@ module ActionController
         exception_class_name = payload[:exception].first
         status = ActionDispatch::ExceptionWrapper.status_code_for_exception(exception_class_name)
       end
-      message = "Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in %.0fms" % event.duration
+      message = "Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in #{format_duration(event.duration)}"
       message << " (#{additions.join(" | ")})" unless additions.blank?
 
       info(message)
@@ -34,9 +34,7 @@ module ActionController
     end
 
     def send_file(event)
-      message = "Sent file %s"
-      message << " (%.1fms)"
-      info(message % [event.payload[:path], event.duration])
+      info("Sent file #{event.payload[:path]} (#{format_duration(event.duration)})")
     end
 
     def redirect_to(event)
@@ -44,7 +42,7 @@ module ActionController
     end
 
     def send_data(event)
-      info("Sent data %s (%.1fms)" % [event.payload[:filename], event.duration])
+      info("Sent data #{event.payload[:filename]}  (#{format_duration(event.duration)})")
     end
 
     %w(write_fragment read_fragment exist_fragment?
@@ -53,7 +51,8 @@ module ActionController
         def #{method}(event)
           key_or_path = event.payload[:key] || event.payload[:path]
           human_name  = #{method.to_s.humanize.inspect}
-          info("\#{human_name} \#{key_or_path} \#{"(%.1fms)" % event.duration}")
+          duration = format_duration(event.duration)
+          info("\#{human_name} \#{key_or_path} \#{duration}")
         end
       METHOD
     end
diff --git a/activesupport/lib/active_support/log_subscriber.rb b/activesupport/lib/active_support/log_subscriber.rb
index 6296c1d4b8..ed7c73b6af 100644
--- a/activesupport/lib/active_support/log_subscriber.rb
+++ b/activesupport/lib/active_support/log_subscriber.rb
@@ -118,5 +118,9 @@ module ActiveSupport
       bold  = bold ? BOLD : ""
       "#{bold}#{color}#{text}#{CLEAR}"
     end
+
+    def format_duration(duration)
+      "%.1fms" % duration
+    end
   end
 end