/* * Kernel module for testing copy_to/from_user infrastructure. * * Copyright 2013 Google Inc. All Rights Reserved * * Authors: *      Kees Cook       <keescook@chromium.org> * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/mman.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/uaccess.h>#include <linux/vmalloc.h> #define test(condition, msg)		\({					\	int cond = (condition);		\	if (cond)			\		pr_warn("%s\n", msg);	\	cond;				\}) static int __init test_user_copy_init(void){	int ret = 0;	char *kmem;	char __user *usermem;	char *bad_usermem;	unsigned long user_addr;	unsigned long value = 0x5A; 	kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);	if (!kmem)		return -ENOMEM; 	user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2,			    PROT_READ | PROT_WRITE | PROT_EXEC,			    MAP_ANONYMOUS | MAP_PRIVATE, 0);	if (user_addr >= (unsigned long)(TASK_SIZE)) {		pr_warn("Failed to allocate user memory\n");		kfree(kmem);		return -ENOMEM;	} 	usermem = (char __user *)user_addr;	bad_usermem = (char *)user_addr; 	/* Legitimate usage: none of these should fail. */	ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),		    "legitimate copy_from_user failed");	ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),		    "legitimate copy_to_user failed");	ret |= test(get_user(value, (unsigned long __user *)usermem),		    "legitimate get_user failed");	ret |= test(put_user(value, (unsigned long __user *)usermem),		    "legitimate put_user failed"); 	/* Invalid usage: none of these should succeed. */	ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),				    PAGE_SIZE),		    "illegal all-kernel copy_from_user passed");	ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,				    PAGE_SIZE),		    "illegal reversed copy_from_user passed");	ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,				  PAGE_SIZE),		    "illegal all-kernel copy_to_user passed");	ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,				  PAGE_SIZE),		    "illegal reversed copy_to_user passed");	ret |= test(!get_user(value, (unsigned long __user *)kmem),		    "illegal get_user passed");	ret |= test(!put_user(value, (unsigned long __user *)kmem),		    "illegal put_user passed"); 	vm_munmap(user_addr, PAGE_SIZE * 2);	kfree(kmem); 	if (ret == 0) {		pr_info("tests passed.\n");		return 0;	} 	return -EINVAL;} module_init(test_user_copy_init); static void __exit test_user_copy_exit(void){	pr_info("unloaded.\n");} module_exit(test_user_copy_exit); MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");MODULE_LICENSE("GPL");