| // 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 |
| // Look at assembly with: objdump -drl a.out |
| |
| #include <dlfcn.h> |
| #include <assert.h> |
| |
| extern "C" int printf(const char *, ...); |
| |
| static int counter = 0; |
| |
| template <int i> struct base |
| { |
| virtual void inc() { counter += i; } |
| }; |
| |
| template <int i> struct derived: base<i> |
| { |
| virtual void inc() { counter += (10*i); } |
| }; |
| |
| // We don't use this class. It is just here so that the |
| // compiler does not devirtualize calls to derived::inc() |
| template <int i> struct derived2: derived<i> |
| { |
| virtual void inc() { counter += (20*i); } |
| }; |
| |
| static base<TPID> * bp = new base<TPID>(); |
| static derived<TPID> * dp = new derived<TPID>(); |
| static base<TPID> * dbp = new derived<TPID>(); |
| |
| // Given 2 pointers to C++ objects (non PODs), exchange the pointers to vtable |
| void exchange_vtptr(void * object1_ptr, void * object2_ptr) |
| { |
| void ** object1_vtptr_ptr = (void **)object1_ptr; |
| void ** object2_vtptr_ptr = (void **)object2_ptr; |
| void * object1_vtptr = *object1_vtptr_ptr; |
| void * object2_vtptr = *object2_vtptr_ptr; |
| *object1_vtptr_ptr = object2_vtptr; |
| *object2_vtptr_ptr = object1_vtptr; |
| } |
| |
| main() |
| { |
| int prev_counter; |
| |
| exchange_vtptr(bp, dp); |
| exchange_vtptr(bp, dp); |
| exchange_vtptr(bp, dbp); |
| exchange_vtptr(bp, dbp); |
| |
| counter = 0; |
| bp->inc(); |
| dp->inc(); |
| dbp->inc(); |
| assert(counter == (TPID + 10*TPID + 10*TPID)); |
| |
| prev_counter = counter; |
| exchange_vtptr(bp, dp); |
| bp->inc(); // This one should succeed but it is calling the wrong member |
| assert(counter == (prev_counter + 10*TPID)); |
| printf("Pass first attack!\n"); |
| dp->inc(); |
| printf("TPDI=%d counter %d\n", TPID, counter); |
| printf("Pass second attack!\n"); |
| |
| } |