CVE-2022-50537 Linux内核树莓派固件内存泄漏漏洞

/* CVE-2022-50537 PoC - Memory Leak in rpi_firmware_probe() * This PoC demonstrates how to trigger the memory leak by repeatedly * forcing mbox_request_channel() to fail during probe. * * Note: This requires kernel module compilation and root privileges. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/slab.h> static int trigger_probe_failure_count = 0; /* Simulate the vulnerable code path */ static void simulate_vulnerable_probe(void) { struct rpi_firmware *fw; int ret; /* Step 1: Allocate firmware structure (similar to kzalloc in real driver) */ fw = kzalloc(sizeof(struct rpi_firmware), GFP_KERNEL); if (!fw) return; /* Step 2: Simulate mbox_request_channel() failure */ /* In real scenario, this fails when mailbox subsystem is unavailable */ ret = -ENODEV; /* Simulated failure */ if (ret) { /* BUG: 'fw' is not freed here - memory leak! */ /* Fix should add: kfree(fw); before returning */ trigger_probe_failure_count++; printk(KERN_ERR "rpi_firmware: mbox_request_channel failed, " "leaking %zu bytes (leak count: %d)\n", sizeof(struct rpi_firmware), trigger_probe_failure_count); return; /* Memory leak occurs here */ } /* Normal cleanup - only reached on success */ kfree(fw); } static int __init poc_init(void) { int i; printk(KERN_INFO "CVE-2022-50537 PoC loaded\n"); /* Trigger the leak multiple times to demonstrate accumulation */ for (i = 0; i < 1000; i++) { simulate_vulnerable_probe(); } printk(KERN_INFO "PoC: Triggered %d memory leaks\n", trigger_probe_failure_count); return 0; } static void __exit poc_exit(void) { printk(KERN_INFO "CVE-2022-50537 PoC unloaded\n"); } module_init(poc_init); module_exit(poc_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("PoC for CVE-2022-50537 rpi_firmware memory leak"); /* Fixed version would include kfree(fw) in the error path: * * if (ret) { * kfree(fw); * return ret; * } */