106 lines
2.7 KiB
Ruby
106 lines
2.7 KiB
Ruby
module Rex
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module Encoder
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###
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#
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# This class implements basic XDR encoding.
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#
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###
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module XDR
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MAX_ARG = 0xffffffff
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# Also: unsigned int, bool, enum
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def XDR.encode_int(int)
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return [int].pack('N')
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end
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def XDR.decode_int!(data)
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return data.slice!(0..3).unpack('N')[0]
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end
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def XDR.encode_lchar(char)
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char |= 0xffffff00 if char & 0x80 != 0
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return encode_int(char)
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end
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def XDR.decode_lchar!(data)
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return (decode_int!(data) & 0xff).chr
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end
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# Also: Variable length opaque
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def XDR.encode_string(str, max=MAX_ARG)
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raise ArgumentError, 'XDR: String too long' if str.length > max
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len = str.length
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str += "\x00" * ((4 - (len & 3)) & 3)
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return encode_int(len) + str
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end
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def XDR.decode_string!(data)
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real_len = decode_int!(data)
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return "" if real_len == 0
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align_len = (real_len + 3) & ~3
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return data.slice!(0..align_len-1).slice(0..real_len-1)
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end
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def XDR.encode_varray(arr, max=MAX_ARG, &block)
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raise ArgumentError, 'XDR: Too many array elements' if arr.length > max
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return encode_int(arr.length) + arr.collect(&block).join(nil)
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end
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def XDR.decode_varray!(data)
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buf = []
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1.upto(decode_int!(data)) { buf.push(yield(data)) }
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return buf
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end
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# encode(0, [0, 1], "foo", ["bar", 4]) does:
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# encode_int(0) +
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# encode_varray([0, 1]) { |i| XDR.encode_int(i) } +
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# encode_string("foo") +
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# encode_string("bar", 4)
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def XDR.encode(*data)
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data.collect do |var|
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if var.kind_of?(String)
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encode_string(var)
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elsif var.kind_of?(Integer)
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encode_int(var)
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elsif var.kind_of?(Array) && var[0].kind_of?(String)
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raise ArgumentError, 'XDR: Incorrect string array arguments' if var.length != 2
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encode_string(var[0], var[1])
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elsif var.kind_of?(Array) && var[0].kind_of?(Integer)
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encode_varray(var) { |i| XDR.encode_int(i) }
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# 0 means an empty array index in the case of Integer and an empty string in
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# the case of String so we get the best of both worlds
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elsif var.kind_of?(Array) && var[0].nil?
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encode_int(0)
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else
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type = var.class
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type = var[0].class if var.kind_of?(Array)
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raise TypeError, "XDR: encode does not support #{type}"
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end
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end.join(nil)
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end
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# decode(buf, Integer, String, [Integer], [String]) does:
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# [decode_int!(buf), decode_string!(buf),
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# decode_varray!(buf) { |i| XDR.decode_int!(i) },
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# decode_varray!(buf) { |s| XDR.decode_string(s) }]
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def XDR.decode!(buf, *data)
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return *data.collect do |var|
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if data.length == 0
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elsif var.kind_of?(Array) && var[0] == String
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decode_varray!(buf) { |s| XDR.decode_string!(s) }
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elsif var.kind_of?(Array) && var[0] == Integer
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decode_varray!(buf) { |i| XDR.decode_int!(i) }
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elsif var == String
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decode_string!(buf)
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elsif var == Integer
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decode_int!(buf)
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end
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end
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end
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end
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end
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end
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