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mirror of https://github.com/rapid7/metasploit-framework synced 2024-11-05 14:57:30 +01:00
metasploit-framework/modules/nops/x86/single_byte.rb
Spoon M 55f8cdb41a motisha4lif
git-svn-id: file:///home/svn/incoming/trunk@2691 4d416f70-5f16-0410-b530-b9f4589650da
2005-07-09 21:22:32 +00:00

140 lines
4.0 KiB
Ruby

require 'msf/core'
module Msf
module Nops
module IA32
###
#
# SingleByte
# ----------
#
# This class implements single-byte NOP generation for IA32. It takes from
# ADMmutate and from spoonfu.
#
###
class SingleByte < Msf::Nop
SINGLE_BYTE_SLED =
{
# opcode affected registers
# ------ ------------------
"\x90" => nil , # nop
"\x97" => [ 'eax', 'edi' ], # xchg eax, edi
"\x96" => [ 'eax', 'esi' ], # xchg eax,esi
"\x95" => [ 'eax', 'ebp' ], # xchg eax,ebp
"\x93" => [ 'eax', 'ebx' ], # xchg eax,ebx
"\x92" => [ 'eax', 'edx' ], # xchg eax,edx
"\x91" => [ 'eax', 'ecx' ], # xchg eax,ecx
"\x99" => [ 'edx' ], # cdq
"\x4d" => [ 'ebp' ], # dec ebp
"\x48" => [ 'eax' ], # dec eax
"\x47" => [ 'edi' ], # inc edi
"\x4f" => [ 'edi' ], # dec edi
"\x40" => [ 'eax' ], # inc eax
"\x41" => [ 'ecx' ], # inc ecx
"\x37" => [ 'eax' ], # aaa
"\x3f" => [ 'eax' ], # aas
"\x27" => [ 'eax' ], # daa
"\x2f" => [ 'eax' ], # das
"\x46" => [ 'esi' ], # inc esi
"\x4e" => [ 'esi' ], # dec esi
"\xfc" => nil , # cld
"\xfd" => nil , # std
"\xf8" => nil , # clc
"\xf9" => nil , # stc
"\xf5" => nil , # cmc
"\x98" => [ 'eax' ], # cwde
"\x9f" => [ 'eax' ], # lahf
"\x4a" => [ 'edx' ], # dec edx
"\x44" => [ 'esp' ], # inc esp
"\x42" => [ 'edx' ], # inc edx
"\x43" => [ 'ebx' ], # inc ebx
"\x49" => [ 'ecx' ], # dec ecx
"\x4b" => [ 'ebx' ], # dec ebx
"\x45" => [ 'ebp' ], # inc ebp
"\x4c" => [ 'esp' ], # dec esp
"\x9b" => nil , # wait
"\x60" => [ 'esp' ], # pusha
"\x0e" => [ 'esp' ], # push cs
"\x1e" => [ 'esp' ], # push ds
"\x50" => [ 'esp' ], # push eax
"\x55" => [ 'esp' ], # push ebp
"\x53" => [ 'esp' ], # push ebx
"\x51" => [ 'esp' ], # push ecx
"\x57" => [ 'esp' ], # push edi
"\x52" => [ 'esp' ], # push edx
"\x06" => [ 'esp' ], # push es
"\x56" => [ 'esp' ], # push esi
"\x54" => [ 'esp' ], # push esp
"\x16" => [ 'esp' ], # push ss
"\x58" => [ 'esp', 'eax' ], # pop eax
"\x5d" => [ 'esp', 'ebp' ], # pop ebp
"\x5b" => [ 'esp', 'ebx' ], # pop ebx
"\x59" => [ 'esp', 'ecx' ], # pop ecx
"\x5f" => [ 'esp', 'edi' ], # pop edi
"\x5a" => [ 'esp', 'edx' ], # pop edx
"\x5e" => [ 'esp', 'esi' ], # pop esi
"\xd6" => [ 'eax' ], # salc
}
def initialize
super(
'Name' => 'Single Byte',
'Alias' => 'ia32_singlebyte',
'Version' => '$Revision$',
'Description' => 'Single-byte NOP generator',
'Author' => 'spoonm',
'Arch' => ARCH_IA32)
end
# Generate a single-byte NOP sled for IA32
def generate_sled(length, opts)
sled_hash = SINGLE_BYTE_SLED
sled_max_idx = sled_hash.length
sled_cur_idx = 0
out_sled = ''
random = opts['Random'] || false
badchars = opts['Badchars'] || ''
badregs = opts['SaveRegisters'] || []
# Generate the whole sled...
1.upto(length) { |current|
cur_char = nil
threshold = 0
# Keep snagging characters until we find one that satisfies both the
# bad character and bad register requirements
begin
sled_cur_idx = rand(sled_max_idx) if (random)
cur_char = sled_hash.keys[sled_cur_idx]
sled_cur_idx += 1 if (!random)
# Make sure that we haven't gone over the sled repeat threshold
if ((threshold += 1) > self.nop_repeat_threshold)
return nil
end
end while ((badchars.include?(cur_char)) or
((sled_hash[cur_char]) and
((sled_hash[cur_char] & badregs)).length > 0))
# Add the character to the sled now that it's passed our checks
out_sled += cur_char
}
# If the sled fails to entirely generate itself, then that's bogus,
# man...
if (out_sled.length != length)
return nil
end
return out_sled
end
end
end end end