96 lines
2.4 KiB
Ruby
96 lines
2.4 KiB
Ruby
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# This file is part of Metasm, the Ruby assembly manipulation suite
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# Copyright (C) 2006-2009 Yoann GUILLOT
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#
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# Licence is LGPL, see LICENCE in the top-level directory
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# metasm dasm plugin: allow patching the file from the dasm interface
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# use P to assemble a new instruction at the current address
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# backup the executable file
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def backup_program_file
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f = @program.filename
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if File.exist?(f) and not File.exist?(f + '.bak')
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File.open(f + '.bak', 'wb') { |wfd|
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File.open(f, 'rb') { |rfd|
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while buf = rfd.read(1<<16)
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wfd.write buf
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end
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}
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}
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end
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end
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# create a backup and reopen the backend VirtualFile RW
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def reopen_rw(addr=nil, edata=nil)
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if not edata
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sections.each { |k, v| reopen_rw(k, v) }
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return true
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end
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return if not File.writable?(@program.filename)
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backup_program_file
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if not edata.data.kind_of? VirtualFile
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# section too small, loaded as real String
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# force reopen as VFile (allow hexediting in gui)
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return if not off = addr_to_fileoff(addr)
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len = edata.data.length
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edata.data = VirtualFile.read(@program.filename, 'rb+').dup(off, len)
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else
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edata.data.fd.reopen @program.filename, 'rb+'
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end
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end
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raise "cant find original file" if not @program.filename or not File.exist? @program.filename
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reopen_rw
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def patch_instrs(addr, asmsrc)
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sc = Metasm::Shellcode.new(cpu, addr) # pfx needed for autorequire
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sc.assemble(asmsrc, cpu)
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sc.encoded.fixup! prog_binding # allow references to dasm labels in the shellcode
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raw = sc.encode_string
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if s = get_section_at(addr) and s[0].data.kind_of? VirtualFile
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s[0][s[0].ptr, raw.length] = raw
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elsif o = addr_to_fileoff(addr) # section too small, not loaded as a VirtFile
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backup_program_file
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File.open(@program.filename, 'rb+') { |fd|
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fd.pos = o
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fd.write raw
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}
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s[0][s[0].ptr, raw.length] = raw if s
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else
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return
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end
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b = split_block(addr)
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# clear what we had in the rewritten space
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raw.length.times { |rawoff|
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next if not di = di_at(addr+rawoff)
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di.block.list.each { |ldi| @decoded.delete ldi.address }
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}
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disassemble_fast(addr) if b
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if b and @decoded[addr]
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nb = @decoded[addr].block
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nb.from_normal = b.from_normal
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nb.from_subfuncret = b.from_subfuncret
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nb.from_indirect = b.from_indirect
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end
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true
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end
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if gui
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gui.keyboard_callback[?P] = lambda { |k|
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addr = gui.curaddr
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gui.inputbox('new instructions') { |src|
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src = src.gsub(/;\s+/, "\n")
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patch_instrs(addr, src)
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gui.gui_update
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}
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true
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}
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end
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