Land #66, Cleanup masm format logic

lib/rex/text/hex.rb

@@ -171,8 +171,8 @@ def self.dehex!(str)
     #
     # General-case method to handle both "\xAA\xBB\xCC" format and 0xAA,0xBB,0xCC format
     #
-    def self.hexify_general(str, char_prefix, col = DefaultWrap, line_start = '', line_end = '', buf_start = '', buf_end = '', between='')
-      encoded_char_length = 2 + char_prefix.length + between.length
+    def self.hexify_general(str, char_prefix, col = DefaultWrap, line_start = '', line_end = '', buf_start = '', buf_end = '', between='', char_suffix: '')
+      encoded_char_length = 2 + char_prefix.length + char_suffix.length + between.length
       if col < line_start.length + encoded_char_length + line_end.length
         # raise an exception
         raise ArgumentError.new('insufficient column width')
@@ -188,7 +188,7 @@ def self.hexify_general(str, char_prefix, col = DefaultWrap, line_start = '', li
           ret << "#{line_end}\n#{line_start}"
           last_line_length = line_start.length
         end
-        ret << char_prefix << char.unpack('H*')[0] << between
+        ret << char_prefix << char.unpack('H*')[0] << char_suffix << between
         last_line_length += encoded_char_length
       end
       # Remove the last in-between characters, if required

lib/rex/text/lang.rb

@@ -48,17 +48,17 @@ def self.to_golang_comment(str,  wrap = DefaultWrap)
     #
     # Converts to a masm style array of bytes
     #
-    def self.to_masm(str, wrap = DefaultWrap, name = "")
-      raise ArgumentError.new('str can not be empty') if str.empty?
-      a = to_hex(str)
-      a.gsub!(/\\x/, '')
-      a.gsub!(/(.{2})/, '\1h,')
-      a.gsub!(/(.{32})/, '\1\n')
-      a.gsub!('\n', "\n")
-      a.gsub!(/^(.*),$/, 'DB \1')
-      a.gsub!(/([a-f].h)/, '0\1')
-      a.sub!(/^/, 'shellcode ')
-      return a
+    def self.to_masm(str, wrap = DefaultWrap, name = "buf")
+      result = hexify_general(str, "", wrap, "#{' ' * (name.length + 1)}DB ", '', "#{name} DB ", '', ',', char_suffix: 'h')
+      result.gsub!(",\n", "\n")
+      result
+    end
+
+    #
+    # Creates a masm style comment
+    #
+    def self.to_masm_comment(str, wrap = DefaultWrap)
+      return wordwrap(str, 0, wrap, '', '; ')
     end
 
     #
@@ -72,7 +72,6 @@ def self.to_masm_comment(str,  wrap = DefaultWrap)
     # Converts to a nim style array of bytes
     #
     def self.to_nim(str, wrap = DefaultWrap, name = "buf")
-      raise ArgumentError.new('str can not be empty') if str.empty?
       return numhexify(str, wrap, '', '',  "var #{name}: array[#{str.length}, byte] = [\nbyte ", "]", ',')
     end
 
@@ -89,7 +88,7 @@ def self.to_nim_comment(str,  wrap = DefaultWrap)
     def self.to_rust(str, wrap = DefaultWrap, name = "buf")
       return numhexify(str, wrap, '', '',  "let #{name}: [u8; #{str.length}] = [", "];", ',')
     end
-    
+
     #
     # Creates a Rust style comment
     #

spec/rex/text/lang_spec.rb

@@ -23,10 +23,6 @@
       "buf :=  []byte{0x41,0x41,0x41,\n0x41,0x41,0x41,0x41,0x41,0x41,\n0x41};\n"
     end
 
-    let(:expected_masm) do
-      "shellcode DB 41h,41h,41h,41h,41h,41h,41h,41h\nDB 41h,41h"
-    end
-
     let(:expected_nim) do
       "var buf: array[10, byte] = [\nbyte 0x41,0x41,0x41,0x41,0x41,\n0x41,0x41,0x41,0x41,0x41]\n"
     end
@@ -67,9 +63,30 @@
       expect(output).to eq(expected_golang)
     end
 
-    it "masm is as expected" do
-      output = described_class.to_masm('A' * 10, 30)
-      expect(output).to eq(expected_masm)
+    describe '#to_masm' do
+      [
+        {
+          args: ['A' * 10, 80],
+          expected: "buf DB 41h,41h,41h,41h,41h,41h,41h,41h,41h,41h\n"
+        },
+        {
+          args: ['A' * 10, 30],
+          expected: "buf DB 41h,41h,41h,41h,41h\n    DB 41h,41h,41h,41h,41h\n"
+        },
+        {
+          args: [(0..24).to_a.pack("C*"), 50],
+          expected: "buf DB 00h,01h,02h,03h,04h,05h,06h,07h,08h,09h\n    DB 0ah,0bh,0ch,0dh,0eh,0fh,10h,11h,12h,13h\n    DB 14h,15h,16h,17h,18h\n"
+        },
+        {
+          args: [('A'..'Z').to_a.join, 50],
+          expected: "buf DB 41h,42h,43h,44h,45h,46h,47h,48h,49h,4ah\n    DB 4bh,4ch,4dh,4eh,4fh,50h,51h,52h,53h,54h\n    DB 55h,56h,57h,58h,59h,5ah\n"
+        }
+      ].each do |test|
+        it "formats #{test} as expected" do
+          output = described_class.to_masm(*test[:args])
+          expect(output).to eq(test[:expected])
+        end
+      end
     end
 
     it "nim is as expected" do