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