Finished injection module at userspace using /proc/<pid>/maps, enables to overwrite the GOT section with RELRO activated

src/helpers/simple_timer.c

@@ -0,0 +1,110 @@
+/**
+ * Modified version of Linux man page timer using timerfd.
+ * Counts to 3, 1 second at a time, then sets another time up to 3, one second at a time.
+ */
+
+#include <sys/timerfd.h>
+#include <time.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+
+void print_elapsed_time() {
+    static struct timespec start;
+    struct timespec curr;
+    static int first_call = 1;
+    int secs, nsecs;
+
+    if (first_call) {
+        first_call = 0;
+        if (clock_gettime(CLOCK_MONOTONIC, &start) == -1){
+            perror("clock_gettime");
+            return;   
+        }
+    }
+
+    if (clock_gettime(CLOCK_MONOTONIC, &curr) == -1){
+        perror("clock_gettime");
+        return;
+    }
+        
+    secs = curr.tv_sec - start.tv_sec;
+    nsecs = curr.tv_nsec - start.tv_nsec;
+    if (nsecs < 0) {
+        secs--;
+        nsecs += 1000000000;
+    }
+    printf("Timer called at: %d.%03d: ", secs, (nsecs + 500000) / 1000000);
+}
+
+int main(int argc, char *argv[]) {
+    struct itimerspec new_value;
+    int max_exp, fd;
+    struct timespec now;
+    uint64_t exp;
+    ssize_t s;
+
+    if (clock_gettime(CLOCK_REALTIME, &now) == -1){
+        perror("clock_gettime");
+        return -1;
+    }
+       
+    new_value.it_value.tv_sec = now.tv_sec +1;
+    new_value.it_value.tv_nsec = now.tv_nsec;
+    new_value.it_interval.tv_sec = 1;
+    new_value.it_interval.tv_nsec = 0;
+    max_exp = 3;
+
+    fd = timerfd_create(CLOCK_REALTIME, 0);
+    if (fd == -1){
+        perror("timerfd_create");
+        return -1;
+    }
+
+    if (timerfd_settime(fd, TFD_TIMER_ABSTIME, &new_value, NULL) == -1){
+        perror("timerfd_settime");
+        return -1;
+    }
+
+    printf("Timer started\n");
+
+    for (uint64_t tot_exp = 0; tot_exp < max_exp;) {
+        s = read(fd, &exp, sizeof(uint64_t));
+        if (s != sizeof(uint64_t))
+            perror("Error reading from timer");
+
+        tot_exp += exp;
+        print_elapsed_time();
+        printf("time between: %llu; total elapsed time=%llu\n", (unsigned long long) exp, (unsigned long long) tot_exp);
+    }
+
+    if (clock_gettime(CLOCK_REALTIME, &now) == -1){
+        perror("clock_gettime");
+        return -1;
+    }
+
+    new_value.it_value.tv_sec = now.tv_sec +1;
+    new_value.it_value.tv_nsec = now.tv_nsec;
+    new_value.it_interval.tv_sec = 1;
+    new_value.it_interval.tv_nsec = 0;
+    max_exp = 3;
+
+    if (timerfd_settime(fd, TFD_TIMER_ABSTIME, &new_value, NULL) == -1){
+        perror("timerfd_settime");
+        return -1;
+    }
+
+    for (uint64_t tot_exp = 0; tot_exp < max_exp;) {
+        s = read(fd, &exp, sizeof(uint64_t));
+        if (s != sizeof(uint64_t))
+            perror("Error reading from timer");
+
+        tot_exp += exp;
+        print_elapsed_time();
+        printf("time between: %llu; total elapsed time=%llu\n", (unsigned long long) exp, (unsigned long long) tot_exp);
+    }
+
+
+   return 0;
+}