HD Moore
e02eb0d2eb
Fixed multiple CPU spinning bugs in the alpha2 encoders Fixed SiteReference to expose site type and value git-svn-id: file:///home/svn/incoming/trunk@3401 4d416f70-5f16-0410-b530-b9f4589650da
296 lines
7.1 KiB
Ruby
296 lines
7.1 KiB
Ruby
require 'msf/core'
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module Msf
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###
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#
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# This class wrappers an encoded payload buffer and the means used to create
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# one.
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#
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###
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class EncodedPayload
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include Framework::Offspring
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#
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# This method creates an encoded payload instance and returns it to the
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# caller.
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#
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def self.create(pinst, reqs)
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# Create the encoded payload instance
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p = EncodedPayload.new(pinst.framework, pinst, reqs)
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p.generate
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return p
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end
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#
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# Creates an instance of an EncodedPayload.
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#
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def initialize(framework, pinst, reqs)
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self.framework = framework
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self.pinst = pinst
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self.reqs = reqs
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end
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#
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# This method enerates the full encoded payload and returns the encoded
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# payload buffer.
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#
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def generate
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self.raw = nil
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self.encoded = nil
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self.nop_sled_size = 0
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self.nop_sled = nil
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self.encoder = nil
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self.nop = nil
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# First, validate
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pinst.validate()
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# Generate the raw version of the payload first
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generate_raw()
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# Encode the payload
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encode()
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# Build the NOP sled
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generate_sled()
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# Finally, set the complete payload definition
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self.encoded = (self.nop_sled || '') + self.encoded
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# Return the complete payload
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return encoded
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end
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#
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# Generates the raw payload from the payload instance. This populates the
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# raw attribute.
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#
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def generate_raw
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self.raw = (reqs['Prepend'] || '') + pinst.generate + (reqs['Append'] || '')
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end
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#
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# Scans for a compatible encoder using ranked precedence and populates the
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# encoded attribute.
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#
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def encode
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# If the exploit has bad characters, we need to run the list of encoders
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# in ranked precedence and try to encode without them.
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if (reqs['BadChars'] or reqs['Encoder'])
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encoders = pinst.compatible_encoders
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# If the caller had a preferred encoder, try to find it and prefix it
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if ((reqs['Encoder']) and
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(preferred = framework.encoders[reqs['Encoder']]))
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encoders.unshift([reqs['Encoder'], preferred ])
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elsif (reqs['Encoder'])
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wlog("#{pinst.refname}: Failed to find preferred encoder #{reqs['Encoder']}")
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end
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encoders.each { |encname, encmod|
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self.encoder = encmod.new
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self.encoded = nil
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# If there is an encoder type restriction, check to see if this
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# encoder matches with what we're searching for.
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if ((reqs['EncoderType']) and
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(self.encoder.encoder_type.split(/\s+/).include?(reqs['EncoderType']) == false))
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wlog("#{pinst.refname}: Encoder #{encoder.refname} is not a compatible encoder type: #{reqs['EncoderType']} != #{self.encoder.encoder_type}",
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'core', LEV_1)
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next
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end
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# If we have any encoder options, import them into the datastore
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# of the encoder.
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if (reqs['EncoderOptions'])
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self.encoder.datastore.import_options_from_hash(reqs['EncoderOptions'])
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end
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# Validate the encoder to make sure it's properly initialized.
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begin
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self.encoder.validate
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rescue ::Exception
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wlog("#{pinst.refname}: Failed to validate encoder #{encoder.refname}: #{$!}",
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'core', LEV_1)
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next
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end
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# Try encoding with the current encoder
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begin
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self.encoded = self.encoder.encode(self.raw, reqs['BadChars'])
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rescue ::Exception
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wlog("#{pinst.refname}: Failed to encode payload with encoder #{encoder.refname}: #{$!}",
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'core', LEV_1)
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dlog("#{pinst.refname}: Call stack\n#{$@.join("\n")}", 'core', LEV_3)
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next
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end
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dlog("#{pinst.refname}: Successfully encoded with encoder #{encoder.refname} (size is #{self.encoded.length})",
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'core', LEV_2)
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# Get the minimum number of nops to use
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min = (reqs['MinNops'] || 0).to_i
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min = 0 if reqs['DisableNops']
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# Check to see if we have enough room for the minimum requirements
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if ((reqs['Space']) and
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(reqs['Space'] < self.encoded.length + min))
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wlog("#{pinst.refname}: Encoded payload version is too large with encoder #{encoder.refname}",
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'core', LEV_1)
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next
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end
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break
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}
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# If the encoded payload is nil, raise an exception saying that we
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# suck at life.
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if (self.encoded == nil)
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encoder = nil
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raise NoEncodersSucceededError,
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"#{pinst.refname}: All encoders failed to encode.",
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caller
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end
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# If there are no bad characters, then the raw is the same as the
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# encoded
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else
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self.encoded = raw
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end
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# Prefix the prepend encoder value
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self.encoded = (reqs['PrependEncoder'] || '') + self.encoded
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end
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#
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# Construct a NOP sled if necessary
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#
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def generate_sled
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min = reqs['MinNops'] || 0
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space = reqs['Space']
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self.nop_sled_size = min
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# Calculate the number of NOPs to pad out the buffer with based on the
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# requirements. If there was a space requirement, check to see if
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# there's any room at all left for a sled.
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if ((space) and
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(space > encoded.length))
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self.nop_sled_size = reqs['Space'] - self.encoded.length
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end
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# If the maximum number of NOPs has been exceeded, wrap it back down.
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if ((reqs['MaxNops']) and
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(reqs['MaxNops'] < self.nop_sled_size))
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self.nop_sled_size = reqs['MaxNops']
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end
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# Check for the DisableNops setting
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self.nop_sled_size = 0 if reqs['DisableNops']
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# Now construct the actual sled
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if (self.nop_sled_size > 0)
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nops = pinst.compatible_nops
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# If the caller had a preferred nop, try to find it and prefix it
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if ((reqs['Nop']) and
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(preferred = framework.nops[reqs['Nop']]))
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nops.unshift([reqs['Nop'], preferred ])
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elsif (reqs['Nop'])
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wlog("#{pinst.refname}: Failed to find preferred nop #{reqs['Nop']}")
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end
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nops.each { |nopname, nopmod|
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# Create an instance of the nop module
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self.nop = nopmod.new
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# The list of save registers
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save_regs = (reqs['SaveRegisters'] || []) + (pinst.save_registers || [])
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if (save_regs.empty? == true)
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save_regs = nil
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end
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begin
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nop.copy_ui(pinst)
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self.nop_sled = nop.generate_sled(self.nop_sled_size,
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'BadChars' => reqs['BadChars'],
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'SaveRegisters' => save_regs)
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rescue
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dlog("#{pinst.refname}: Nop generator #{nop.refname} failed to generate sled for payload: #{$!}",
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'core', LEV_1)
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self.nop = nil
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end
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break
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}
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if (self.nop_sled == nil)
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raise NoNopsSucceededError,
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"#{pinst.refname}: All NOP generators failed to construct sled for.",
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caller
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end
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else
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self.nop_sled = ''
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end
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return self.nop_sled
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end
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#
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# The raw version of the payload
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#
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attr_reader :raw
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#
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# The encoded version of the raw payload plus the NOP sled
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# if one was generated.
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#
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attr_reader :encoded
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#
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# The size of the NOP sled
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#
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attr_reader :nop_sled_size
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#
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# The NOP sled itself
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#
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attr_reader :nop_sled
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#
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# The encoder that was used
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#
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attr_reader :encoder
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#
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# The NOP generator that was used
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#
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attr_reader :nop
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protected
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attr_writer :raw # :nodoc:
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attr_writer :encoded # :nodoc:
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attr_writer :nop_sled_size # :nodoc:
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attr_writer :nop_sled # :nodoc:
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attr_writer :payload # :nodoc:
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attr_writer :encoder # :nodoc:
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attr_writer :nop # :nodoc:
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#
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# The payload instance used to generate the payload
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#
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attr_accessor :pinst
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#
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# The requirements used for generation
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#
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attr_accessor :reqs
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end
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end
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