IDA pro apply .dif back to database

Question

I've modified program database in IDA Pro and then created a .dif file with File -> Produce File -> Create DIF File...

After that I've reverted all my changes to database. Is there a way to apply changes from .dif file back?

Thanks

Answer 1

As far as I understand the .dif file is built as follows - after some initial meaningless lines it contains something like this:

offset_in_file: initial_byte current_byte

So applying the differences to the idb should be easy with simple python function as follows:

#not tested, not checked, not ran even once
#beware of errors, use on your own risk
import idaapi
import idc

def apply_dif_file(dif_file_name):
    f = open(dif_file_name, "r")
    for l in f:
        if l.find(":") == -1:
            continue
        splitted = l.split()
        off_in_file = splitted[0]
        initial_byte = splitted[1]
        new_byte = splitted[2]

        #Converting offset to integer
        #After that converting it to the ea
        offset = int(off_in_file.replace(":", ""), 16)
        ea = idaapi.get_fileregion_ea(offset)
        #converting new byte
        new_byte_num = int(new_byte, 16)

        idc.PatchByte(ea, new_byte_num)
    f.close()

Good luck, note the latest edits.