_initData overwrites data if it lies within the same page

[nemhods]

Injecting data at multiple addresses that lie within the same memory page causes any data but the last to be discarded.

Consider the following IDAPython demo code:

from idaemu import *
import binascii

e = Emu(UC_ARCH_X86, UC_MODE_32)

# write two bytes into the same page

e.setData(0x0FFFFF, b"\xAA") # new page
e.setData(0x100000, b"\xAA") # new page
e.setData(0x100010, b"\xAA") # same page as above, will overwrite data at 0x10000

e.eUntilAddress(0x401000, 0x401000) # run the emulator once to init data

print "0x0FFFFF:", binascii.hexlify(e.curUC.mem_read(0x0FFFFF, 1))
print "0x100000:", binascii.hexlify(e.curUC.mem_read(0x100000, 1)) # this results in 0x00, not 0xAA as expected
print "0x100010:", binascii.hexlify(e.curUC.mem_read(0x100010, 1))

This seems to be occurring because the loop that injects the data into the emulator memory calls uc.mem_map for every data element in the list. If the memory region that is mapped already contains data from a previous call, this data will now be disregarded.

Quick workaround:

    def _initData(self, uc):
        # DIRTY FIX: first loop maps memory
        for address, data, init in self.data:
            addr = self._alignAddr(address)
            size = PAGE_ALIGN
            while addr + size < len(data): size += PAGE_ALIGN
            uc.mem_map(addr, size)
            
        # second loop actually writes
        for address, data, init in self.data:
            addr = self._alignAddr(address)
            size = PAGE_ALIGN
            if init: 
                uc.mem_write(addr, self._getOriginData(addr, size))
            uc.mem_write(address, data)