Guessing Game 1

guessing_game_1/vuln.c

@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#define BUFSIZE 100
+
+
+long increment(long in) {
+	return in + 1;
+}
+
+long get_random() {
+	return rand() % BUFSIZE;
+}
+
+int do_stuff() {
+	long ans = get_random();
+	ans = increment(ans);
+	int res = 0;
+	
+	printf("What number would you like to guess?\n");
+	char guess[BUFSIZE];
+	fgets(guess, BUFSIZE, stdin);
+	
+	long g = atol(guess);
+	if (!g) {
+		printf("That's not a valid number!\n");
+	} else {
+		if (g == ans) {
+			printf("Congrats! You win! Your prize is this print statement!\n\n");
+			res = 1;
+		} else {
+			printf("Nope!\n\n");
+		}
+	}
+	return res;
+}
+
+void win() {
+	char winner[BUFSIZE];
+	printf("New winner!\nName? ");
+	fgets(winner, 360, stdin);
+	printf("Congrats %s\n\n", winner);
+}
+
+int main(int argc, char **argv){
+	setvbuf(stdout, NULL, _IONBF, 0);
+	// Set the gid to the effective gid
+	// this prevents /bin/sh from dropping the privileges
+	gid_t gid = getegid();
+	setresgid(gid, gid, gid);
+	
+	int res;
+	
+	printf("Welcome to my guessing game!\n\n");
+	
+	while (1) {
+		res = do_stuff();
+		if (res) {
+			win();
+		}
+	}
+	
+	return 0;
+}