Hello,
After reading this wikipedia article :
http://en.wikipedia.org/wiki/Self-modifying_code
I am wondering if this technique has been done on iPhone.
Thanks
Thierry
A:
Not allowed by apple, and I believe it's physically prevented, the code space can't be modified, and code cannot run from the data space. (Jailbreaking could fix this however)
Bill K
2010-03-02 22:10:12
A:
A standard iPhone application is unable to set a memory page as executable. So, it's impossible to modify your own code or generate code at runtime (ie.: Just In Time compilation).
A jailbroken device will allow you to have such pages though.
JPD002
2010-03-02 22:24:35
thanks.My goal was to find a way to securing a library which my application was compiled with. Any idea ?
thierryb
2010-03-02 22:32:18
You want to obfuscate the code in your library so people won't reverse engineer it?
JPD002
2010-03-02 23:50:58
yes this is what I need to do
thierryb
2010-03-03 14:08:03
Well, if it's a standard C or C++ library, symbolic information shouldn't appear in the binary generated by the Release configuration. It should be enough to stop anyone who doesn't have knowledge of the ARM architecture.
JPD002
2010-03-03 21:19:50
A:
Three things that are most trecherous:
Connectors that corrode
Recursive algorithms
And self modifying code
-- traditional programmer's chanty
Self modifying code is the easiest and surest way to make code behavior completely unpredictable. It's something that is interesting academically but it is seldom a practical tool.
As near as I can tell, it's primary use is to wreak vengeance on an employer when you know you're going to be fired.
TechZen
2010-03-02 23:13:42