* lib/resolv.rb (Resolv::DNS::Message::MessageDecoder): Raise

  DecodeError if no data before the limit.
  Reported by Will Bryant.  [ruby-core:60557] [Bug #9498]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44884 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/resolv.rb b/lib/resolv.rb
index 579f8885ae..6b2fa9d903 100644
--- a/lib/resolv.rb
+++ b/lib/resolv.rb
@@ -1528,6 +1528,7 @@ class Resolv
         end
 
         def get_bytes(len = @limit - @index)
+          raise DecodeError.new("limit exceeded") if @limit < @index + len
           d = @data[@index, len]
           @index += len
           return d
@@ -1555,6 +1556,7 @@ class Resolv
         end
 
         def get_string
+          raise DecodeError.new("limit exceeded") if @limit <= @index
           len = @data[@index].ord
           raise DecodeError.new("limit exceeded") if @limit < @index + 1 + len
           d = @data[@index + 1, len]
@@ -1578,6 +1580,7 @@ class Resolv
           limit = @index if !limit || @index < limit
           d = []
           while true
+            raise DecodeError.new("limit exceeded") if @limit <= @index
             case @data[@index].ord
             when 0
               @index += 1