From 24aac8b5ae99495281458954e552c7bd46870b54 Mon Sep 17 00:00:00 2001
From: HD Moore <hd_moore@rapid7.com>
Date: Mon, 16 Jul 2007 01:13:25 +0000
Subject: [PATCH] Fixes #127. Applying patch from Alex that solves ASN.1
 encoding issues.

git-svn-id: file:///home/svn/framework3/trunk@5049 4d416f70-5f16-0410-b530-b9f4589650da
---
 lib/rex/proto/smb/utils.rb | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/lib/rex/proto/smb/utils.rb b/lib/rex/proto/smb/utils.rb
index 1ed695eed3..6979b9b1f2 100644
--- a/lib/rex/proto/smb/utils.rb
+++ b/lib/rex/proto/smb/utils.rb
@@ -94,18 +94,29 @@ CONST = Rex::Proto::SMB::Constants
 		return decoded
 	end
 
+	#
+	# Prepends an ASN1 formatted length field to a piece of data
+	#
 	def self.asn1encode(str = '')
 		res = ''
-		case str.length
-			when 0 .. 0x80
-				res = [str.length].pack('C') + str
-			when 0x81 .. 0x100
-				res = [0x81, str.length].pack('CC') + str
-			when 0x101 .. 0x100000
-				res = [0x82, str.length].pack('Cn') + str
-			when  0x100001 .. 0xffffffff
-				res = [0x83, str.length].pack('CN') + str
-		end
+
+		# If the high bit of the first byte is 1, it contains the number of
+		# length bytes that follow
+
+		case data.length
+			when 0 .. 0x7F
+				res = [data.length].pack('C') + data
+			when 0x80 .. 0xFF
+				res = [0x81, data.length].pack('CC') + data
+			when 0x100 .. 0xFFFF
+				res = [0x82, data.length].pack('Cn') + data
+			when  0x10000 .. 0xffffff
+				res = [0x83, data.length >> 16, data.length & 0xFFFF].pack('CCn') + data
+			when  0x1000000 .. 0xffffffff
+				res = [0x84, data.length].pack('CN') + data
+			else
+				raise "ASN1 data too long"
+			end
 		return res
 	end