Step 1: 
B: Another potential patch can be as follows:

1 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom, int newtailroom, gfp_t gfp_mask)
2 {
3     size_t total_size = newheadroom + skb->len + newtailroom;

4     if (total_size > INT_MAX) {
5         return NULL; // Prevent integer overflow
6     }

7     struct sk_buff *n = __alloc_skb(total_size, gfp_mask);

8     if (!n) {
9         return NULL; // Allocation failed
10     }

11     n->len = skb->len;
12     n->data = n->head + newheadroom;
13 
14     memcpy(n->data, skb->data, skb->len);
15     return n;
16 }