Create c00ledit.c

Author: elnx

2023/TCTF/c00ledit.c

@@ -0,0 +1,132 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/unistd.h>
+
+typedef struct
+{
+    long size;
+    char *buf;
+} node_t;
+
+node_t *node_list[0x10] = {0};
+
+void show_menu()
+{
+    puts("1. add");
+    puts("2. delete");
+    puts("3. edit");
+    puts("4. show");
+    puts("5. exit");
+    printf("Your choice: ");
+}
+
+long get_long()
+{
+    char tmp[8];
+    memset(tmp, 0, sizeof(tmp));
+    read(0, tmp, sizeof(tmp));
+    return atol(tmp);
+}
+
+void do_add()
+{
+    static int node_count = 0;
+    if (node_count >= sizeof(node_list) / sizeof(node_list[0]))
+    {
+        puts("Enough!");
+        return;
+    }
+    node_list[node_count] = (node_t *)malloc(sizeof(node_t));
+    node_list[node_count]->size = 0x1000;
+    node_list[node_count]->buf = malloc(0x1000);
+    if (!node_list[node_count]) {
+        perror("malloc");
+        exit(-1);
+    }
+    printf("Current node: %d\n", node_count);
+    ++node_count;
+    return;
+
+    // long idx = get_long();
+    // if (idx >= 0 && idx < sizeof(node_list) / sizeof(node_list[0]))
+    // {
+    //     node_list[idx] = (node_t *)malloc(sizeof(node_t));
+    //     node_list[idx]->size = 0x1000;
+    //     node_list[idx]->buf = malloc(0x1000);
+    //     if (!node_list[idx]->buf)
+    //     {
+    //         perror("malloc");
+    //         exit(-1);
+    //     }
+    // }
+    // else
+    // {
+    //     puts("Invalid!");
+    // }
+}
+
+void do_edit()
+{
+    static int edit_count = 0;
+    if (edit_count > 16)
+    {
+        puts("No chance!");
+        return;
+    }
+    printf("Index: ");
+    long idx = get_long();
+    if (!node_list[idx]) {
+        puts("Invalid index!");
+        return;
+    }
+    printf("Offset: ");
+    long offset = get_long();
+    if (offset + 8 > node_list[idx]->size) {
+        puts("Invalid offset!");
+        return;
+    }
+    printf("Content: ");
+    read(0, node_list[idx]->buf+offset, 8);
+    ++edit_count;
+    return;
+}
+
+int main()
+{
+    for (;;)
+    {
+        show_menu();
+        long choice = get_long();
+        switch (choice)
+        {
+        case 1:
+            do_add();
+            break;
+        case 2:
+            puts("Not implemented!");
+            break;
+        case 3:
+            do_edit();
+            break;
+        case 4:
+            puts("Not implemented!");
+            break;
+        case 5:
+            return 0;
+        default:
+            goto fail;
+        }
+    }
+fail:
+    puts("invalid choice");
+    return -1;
+}
+
+__attribute__((constructor)) void init()
+{
+    setbuf(stdout, NULL);
+    setbuf(stdin, NULL);
+    setbuf(stderr, NULL);
+}