On Mon, Nov 05, 2007 at 10:39:58AM +0100, Andy Polyakov wrote:
>> I believe that -Bsymbolic only gives you a fall sense of security and only
>> makes it a little harder to replace some functions, but not that much.
>
> Consider following snippet:
>
> void foo(){}
> void bar(){foo();}
[...]
> -Bsymbolic resolved and "wired" this intra-library reference already at
> link time! In other words once you enter module through bar, no
> manipulation of symbol table at run-time will trick bar to call anything
> other than foo in same module.
But that doesn't stop you from overwriting bar(), who cares that it
internally calls foo().
>> There are only a few function calls that are direct, most of the
>> library is PIC and uses indirect calls.
>
> -Bsymbolic "rewires" as many indirect calls as possible at link time to
> direct ones. A.
Right, it will only use the PLT for functions in an other library.
Kurt
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