CVE-2026-31703 Linux内核writeback释放后重用漏洞

/* * Conceptual PoC for CVE-2026-31703 * This code simulates the race condition in the kernel. * Actual exploitation requires a specific environment and kernel version. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/fs.h> // Conceptual trigger function void trigger_vulnerability(void) { // In a real scenario, this involves heavy file I/O operations // that trigger wb (writeback) switching frequently. // The goal is to hit the window where switch_wbs_ctxs is empty // but switch_work is pending. // Simulating wb_queue_isw adding items // while inode_switch_wbs_work_fn is looping. printk(KERN_INFO "Attempting to trigger CVE-2026-31703 race condition...\n"); // Loop to increase probability of hitting the race for (int i = 0; i < 10000; i++) { // Perform operations that dirty pages and trigger writeback // (e.g., write to a file, sync) } } int init_module(void) { printk(KERN_INFO "CVE-2026-31703 PoC Module Loaded\n"); trigger_vulnerability(); return 0; } void cleanup_module(void) { printk(KERN_INFO "CVE-2026-31703 PoC Module Unloaded\n"); } MODULE_LICENSE("GPL");