70 lines
1.9 KiB
C++
70 lines
1.9 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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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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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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// 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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typedef void * vtptr;
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vtptr * object1_vtptr_ptr = (vtptr *)object1_ptr;
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vtptr * object2_vtptr_ptr = (vtptr *)object2_ptr;
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vtptr object1_vtptr = *object1_vtptr_ptr;
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vtptr object2_vtptr = *object2_vtptr_ptr;
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*object1_vtptr_ptr = object2_vtptr;
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*object2_vtptr_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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exchange_vtptr(bp, dp);
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exchange_vtptr(bp, dp);
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exchange_vtptr(bp, dbp);
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exchange_vtptr(bp, dbp);
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counter = 0;
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bp->inc();
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dp->inc();
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dbp->inc();
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assert(counter == (TPID + 10*TPID + 10*TPID));
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prev_counter = counter;
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exchange_vtptr(bp, dp);
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bp->inc(); // This one should succeed 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!\n");
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dp->inc();
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printf("TPDI=%d counter %d\n", TPID, counter);
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printf("Pass second attack!\n");
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}
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