module Rex::Encoder::XDR
This class implements basic XDR
encoding.
Constants
- MAX_ARG
Public Class Methods
decode!(buf, *data)
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decode(buf, Integer, String, [Integer], [String]) does: [decode_int!(buf), decode_string!(buf),
decode_varray!(buf) { |i| XDR.decode_int!(i) }, decode_varray!(buf) { |s| XDR.decode_string(s) }]
# File lib/rex/encoder/xdr.rb, line 90 def XDR.decode!(buf, *data) return *data.collect do |var| if data.length == 0 elsif var.kind_of?(Array) && var[0] == String decode_varray!(buf) { |s| XDR.decode_string!(s) } elsif var.kind_of?(Array) && var[0] == Integer decode_varray!(buf) { |i| XDR.decode_int!(i) } elsif var == String decode_string!(buf) elsif var == Integer decode_int!(buf) end end end
decode_int!(data)
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# File lib/rex/encoder/xdr.rb, line 17 def XDR.decode_int!(data) raise ArgumentError, 'XDR: No Integer data to decode' unless data raise ArgumentError, "XDR: Too little data to decode (#{data.size})" if data.size < 4 return data.slice!(0..3).unpack('N')[0] end
decode_lchar!(data)
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# File lib/rex/encoder/xdr.rb, line 28 def XDR.decode_lchar!(data) return (decode_int!(data) & 0xff).chr end
decode_string!(data)
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# File lib/rex/encoder/xdr.rb, line 40 def XDR.decode_string!(data) real_len = decode_int!(data) return "" if real_len == 0 align_len = (real_len + 3) & ~3 return data.slice!(0..align_len-1).slice(0..real_len-1) end
decode_varray!(data) { |data| ... }
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# File lib/rex/encoder/xdr.rb, line 52 def XDR.decode_varray!(data) buf = [] 1.upto(decode_int!(data)) { buf.push(yield(data)) } return buf end
encode(*data)
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encode(0, [0, 1], “foo”, [“bar”, 4]) does:
encode_int(0) + encode_varray([0, 1]) { |i| XDR.encode_int(i) } + encode_string("foo") + encode_string("bar", 4)
# File lib/rex/encoder/xdr.rb, line 63 def XDR.encode(*data) data.collect do |var| if var.kind_of?(String) encode_string(var) elsif var.kind_of?(Integer) encode_int(var) elsif var.kind_of?(Array) && var[0].kind_of?(String) raise ArgumentError, 'XDR: Incorrect string array arguments' if var.length != 2 encode_string(var[0], var[1]) elsif var.kind_of?(Array) && var[0].kind_of?(Integer) encode_varray(var) { |i| XDR.encode_int(i) } # 0 means an empty array index in the case of Integer and an empty string in # the case of String so we get the best of both worlds elsif var.kind_of?(Array) && var[0].nil? encode_int(0) else type = var.class type = var[0].class if var.kind_of?(Array) raise TypeError, "XDR: encode does not support #{type}" end end.join(nil) end
encode_int(int)
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Also: unsigned int, bool, enum
# File lib/rex/encoder/xdr.rb, line 13 def XDR.encode_int(int) return [int].pack('N') end
encode_lchar(char)
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# File lib/rex/encoder/xdr.rb, line 23 def XDR.encode_lchar(char) char |= 0xffffff00 if char & 0x80 != 0 return encode_int(char) end
encode_string(str, max=MAX_ARG)
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Also: Variable length opaque
# File lib/rex/encoder/xdr.rb, line 33 def XDR.encode_string(str, max=MAX_ARG) raise ArgumentError, 'XDR: String too long' if str.length > max len = str.length str << "\x00" * ((4 - (len & 3)) & 3) return encode_int(len) + str end
encode_varray(arr, max=MAX_ARG, &block)
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# File lib/rex/encoder/xdr.rb, line 47 def XDR.encode_varray(arr, max=MAX_ARG, &block) raise ArgumentError, 'XDR: Too many array elements' if arr.length > max return encode_int(arr.length) + arr.collect(&block).join(nil) end