Second CTFs part

lab1_2_recap/02_enchanted_forest/main(1).c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static void setup(void) {
+    setvbuf(stdin, NULL, _IONBF, 0);
+    setvbuf(stdout, NULL, _IONBF, 0);
+    setvbuf(stderr, NULL, _IONBF, 0);
+}
+
+static void default_spell(void) {
+    puts("Poof! A tiny spark flies out... not very impressive.");
+}
+
+__attribute__((noreturn)) static void win(void) {
+    puts("Ancient magic awakens! The forest bows to you.");
+    char *argv[] = {"/bin/sh", NULL};
+    execve("/bin/sh", argv, NULL);
+    _exit(0);
+}
+
+static void vuln(void) {
+    struct {
+        char incantation[64];
+        void (*cast)(void);
+    } spell;
+
+    spell.cast = default_spell;
+
+    printf("Whisper your incantation:\n");
+    read(STDIN_FILENO, spell.incantation, 128);
+
+    printf("Casting spell...\n");
+    spell.cast();
+}
+
+int main(void) {
+    setup();
+    printf("Welcome to the Enchanted Forest!\n");
+    vuln();
+    return 0;
+}