如何检测我的iOS应用程序已启用PIE / ASLR？

Question

I am enabling PIE (position-independent executable)/ASLR (address space layout randomization) for an iPhone app by using the "-w -pie" linking option flag. Is there any way I can ensure that things are now set to work as advertised? I tried printing the address of a variable (Edit: and a function) with NSLog and it comes up the same each time. Am I doing it right?

Answer 1

I know this thread is old, but there is no good answer yet in case someone else stumbles upon it. To check if the PIE flag is set is very simple, just run this command:

otool -hv /path/to/App.app/app

Where [APP] is the executable created after building (not the ipa but the executable, binary file).

You should see something like this:

Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
   MH_MAGIC     ARM         V7  0x00     EXECUTE    19       2708   NOUNDEFS DYLDLINK TWOLEVEL PIE

otool should be included in Xcode but if you don't have it you can install it in Xcode preferences > Downloads > Command Line Tools.

Answer 2

检查函数地址，而不是变量地址。