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126 lines
3.4 KiB
126 lines
3.4 KiB
/* |
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* Kernel module for testing copy_to/from_user infrastructure. |
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* |
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* Copyright 2013 Google Inc. All Rights Reserved |
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* |
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* Authors: |
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* Kees Cook <keescook@chromium.org> |
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* |
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* This software is licensed under the terms of the GNU General Public |
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* License version 2, as published by the Free Software Foundation, and |
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* may be copied, distributed, and modified under those terms. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/mman.h> |
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#include <linux/module.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/uaccess.h> |
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#include <linux/vmalloc.h> |
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#define test(condition, msg) \ |
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({ \ |
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int cond = (condition); \ |
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if (cond) \ |
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pr_warn("%s\n", msg); \ |
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cond; \ |
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}) |
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static int __init test_user_copy_init(void) |
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{ |
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int ret = 0; |
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char *kmem; |
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char __user *usermem; |
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char *bad_usermem; |
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unsigned long user_addr; |
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unsigned long value = 0x5A; |
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kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL); |
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if (!kmem) |
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return -ENOMEM; |
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user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2, |
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PROT_READ | PROT_WRITE | PROT_EXEC, |
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MAP_ANONYMOUS | MAP_PRIVATE, 0); |
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if (user_addr >= (unsigned long)(TASK_SIZE)) { |
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pr_warn("Failed to allocate user memory\n"); |
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kfree(kmem); |
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return -ENOMEM; |
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} |
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usermem = (char __user *)user_addr; |
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bad_usermem = (char *)user_addr; |
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/* |
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* Legitimate usage: none of these copies should fail. |
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*/ |
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ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE), |
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"legitimate copy_from_user failed"); |
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ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE), |
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"legitimate copy_to_user failed"); |
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ret |= test(get_user(value, (unsigned long __user *)usermem), |
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"legitimate get_user failed"); |
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ret |= test(put_user(value, (unsigned long __user *)usermem), |
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"legitimate put_user failed"); |
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/* |
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* Invalid usage: none of these copies should succeed. |
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*/ |
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/* Reject kernel-to-kernel copies through copy_from_user(). */ |
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ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE), |
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PAGE_SIZE), |
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"illegal all-kernel copy_from_user passed"); |
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#if 0 |
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/* |
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* When running with SMAP/PAN/etc, this will Oops the kernel |
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* due to the zeroing of userspace memory on failure. This needs |
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* to be tested in LKDTM instead, since this test module does not |
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* expect to explode. |
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*/ |
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ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem, |
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PAGE_SIZE), |
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"illegal reversed copy_from_user passed"); |
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#endif |
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ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE, |
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PAGE_SIZE), |
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"illegal all-kernel copy_to_user passed"); |
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ret |= test(!copy_to_user((char __user *)kmem, bad_usermem, |
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PAGE_SIZE), |
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"illegal reversed copy_to_user passed"); |
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ret |= test(!get_user(value, (unsigned long __user *)kmem), |
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"illegal get_user passed"); |
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ret |= test(!put_user(value, (unsigned long __user *)kmem), |
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"illegal put_user passed"); |
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vm_munmap(user_addr, PAGE_SIZE * 2); |
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kfree(kmem); |
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if (ret == 0) { |
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pr_info("tests passed.\n"); |
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return 0; |
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} |
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return -EINVAL; |
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} |
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module_init(test_user_copy_init); |
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static void __exit test_user_copy_exit(void) |
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{ |
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pr_info("unloaded.\n"); |
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} |
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module_exit(test_user_copy_exit); |
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MODULE_AUTHOR("Kees Cook <keescook@chromium.org>"); |
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MODULE_LICENSE("GPL");
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