95 lines
2.6 KiB
C++
95 lines
2.6 KiB
C++
// Compile with /home/llozano/local2/proj/vtable/gcc-root/usr/local/bin/g++ -m32 -fvtable-verify=std -fpic -rdynamic -Wl,-R,/home/llozano/local2/proj/vtable/gcc-root/usr/local/lib32:./lib32 -I/home/llozano/local2/proj/vtable/vt2/gcc-4_6-mobile-vtable-security//libstdc++-v3/libsupc++ temp_deriv.cc -O0 -ldl -lpthread -Wl,--whole-archive,-lvtv_init,--no-whole-archive,-z,relro -DTPID=0 -g
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// Look at assembly with: objdump -drl a.out
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#include <dlfcn.h>
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#include <assert.h>
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#include <stdlib.h>
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extern "C" int printf(const char *, ...);
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static int counter = 0;
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int i = TPID;
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struct base
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{
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virtual void inc() { counter += i; }
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};
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struct derived: public base
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{
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virtual void inc() { counter += (10*i); }
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};
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// We don't use this class. It is just here so that the
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// compiler does not devirtualize calls to derived::inc()
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struct derived2: public derived
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{
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virtual void inc() { counter += (20*i); }
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};
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/*
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static base * bp = new base();
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static derived * dp = new derived();
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static base * dbp = new derived();
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*/
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struct my_struct {
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base *bp;
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derived *dp;
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base *dbp;
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};
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typedef void * vtptr;
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vtptr get_vtptr(void * object_ptr)
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{
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vtptr * object_vtptr_ptr = (vtptr *)object_ptr;
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return *object_vtptr_ptr;
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}
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void set_vptr(void * object_ptr, vtptr vtp)
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{
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vtptr * object_vtptr_ptr = (vtptr *)object_ptr;
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*object_vtptr_ptr = vtp;
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}
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// Given 2 pointers to C++ objects (non PODs), exchange the pointers to vtable
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void exchange_vtptr(void * object1_ptr, void * object2_ptr)
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{
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vtptr object1_vtptr = get_vtptr(object1_ptr);
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vtptr object2_vtptr = get_vtptr(object2_ptr);
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set_vptr(object1_ptr, object2_vtptr);
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set_vptr(object2_ptr, object1_vtptr);
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}
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main()
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{
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int prev_counter;
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struct my_struct *my_obj = (struct my_struct *) malloc (sizeof (struct my_struct));
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my_obj->bp = new base();
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my_obj->dp = new derived ();
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my_obj->dbp = new derived ();
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counter = 0;
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my_obj->bp->inc();
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my_obj->dp->inc();
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my_obj->dbp->inc();
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assert(counter == (TPID + 10*TPID + 10*TPID));
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prev_counter = counter;
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printf("before ex bp vptr=%x dp vptr=%x\n", get_vtptr(my_obj->bp), get_vtptr(my_obj->dp));
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exchange_vtptr(my_obj->bp, my_obj->dp);
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printf("after ex bp vptr=%x dp vptr=%x\n", get_vtptr(my_obj->bp), get_vtptr(my_obj->dp));
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my_obj->bp->inc(); // This one should not abort but it is calling the wrong member
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assert(counter == (prev_counter + 10*TPID));
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printf("Pass first attack! Expected!\n");
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printf("TPDI=%d counter %d\n", TPID, counter);
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my_obj->dp->inc();
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printf("Pass second attack! SHOULD NOT BE HERE!\n");
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printf("TPDI=%d counter %d\n", TPID, counter);
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exit(1);
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}
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