+++ /dev/null
-/*
- * test_nx.c: functional test for NX functionality
- *
- * (C) Copyright 2008 Intel Corporation
- * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; version 2
- * of the License.
- */
-#include <linux/module.h>
-#include <linux/sort.h>
-#include <linux/slab.h>
-
-#include <linux/uaccess.h>
-#include <asm/asm.h>
-
-extern int rodata_test_data;
-
-/*
- * This file checks 4 things:
- * 1) Check if the stack is not executable
- * 2) Check if kmalloc memory is not executable
- * 3) Check if the .rodata section is not executable
- * 4) Check if the .data section of a module is not executable
- *
- * To do this, the test code tries to execute memory in stack/kmalloc/etc,
- * and then checks if the expected trap happens.
- *
- * Sadly, this implies having a dynamic exception handling table entry.
- * ... which can be done (and will make Rusty cry)... but it can only
- * be done in a stand-alone module with only 1 entry total.
- * (otherwise we'd have to sort and that's just too messy)
- */
-
-
-
-/*
- * We want to set up an exception handling point on our stack,
- * which means a variable value. This function is rather dirty
- * and walks the exception table of the module, looking for a magic
- * marker and replaces it with a specific function.
- */
-static void fudze_exception_table(void *marker, void *new)
-{
- struct module *mod = THIS_MODULE;
- struct exception_table_entry *extable;
-
- /*
- * Note: This module has only 1 exception table entry,
- * so searching and sorting is not needed. If that changes,
- * this would be the place to search and re-sort the exception
- * table.
- */
- if (mod->num_exentries > 1) {
- printk(KERN_ERR "test_nx: too many exception table entries!\n");
- printk(KERN_ERR "test_nx: test results are not reliable.\n");
- return;
- }
- extable = (struct exception_table_entry *)mod->extable;
- extable[0].insn = (unsigned long)new;
-}
-
-
-/*
- * exception tables get their symbols translated so we need
- * to use a fake function to put in there, which we can then
- * replace at runtime.
- */
-void foo_label(void);
-
-/*
- * returns 0 for not-executable, negative for executable
- *
- * Note: we cannot allow this function to be inlined, because
- * that would give us more than 1 exception table entry.
- * This in turn would break the assumptions above.
- */
-static noinline int test_address(void *address)
-{
- unsigned long result;
-
- /* Set up an exception table entry for our address */
- fudze_exception_table(&foo_label, address);
- result = 1;
- asm volatile(
- "foo_label:\n"
- "0: call *%[fake_code]\n"
- "1:\n"
- ".section .fixup,\"ax\"\n"
- "2: mov %[zero], %[rslt]\n"
- " ret\n"
- ".previous\n"
- _ASM_EXTABLE(0b,2b)
- : [rslt] "=r" (result)
- : [fake_code] "r" (address), [zero] "r" (0UL), "0" (result)
- );
- /* change the exception table back for the next round */
- fudze_exception_table(address, &foo_label);
-
- if (result)
- return -ENODEV;
- return 0;
-}
-
-static unsigned char test_data = 0xC3; /* 0xC3 is the opcode for "ret" */
-
-static int test_NX(void)
-{
- int ret = 0;
- /* 0xC3 is the opcode for "ret" */
- char stackcode[] = {0xC3, 0x90, 0 };
- char *heap;
-
- test_data = 0xC3;
-
- printk(KERN_INFO "Testing NX protection\n");
-
- /* Test 1: check if the stack is not executable */
- if (test_address(&stackcode)) {
- printk(KERN_ERR "test_nx: stack was executable\n");
- ret = -ENODEV;
- }
-
-
- /* Test 2: Check if the heap is executable */
- heap = kmalloc(64, GFP_KERNEL);
- if (!heap)
- return -ENOMEM;
- heap[0] = 0xC3; /* opcode for "ret" */
-
- if (test_address(heap)) {
- printk(KERN_ERR "test_nx: heap was executable\n");
- ret = -ENODEV;
- }
- kfree(heap);
-
- /*
- * The following 2 tests currently fail, this needs to get fixed
- * Until then, don't run them to avoid too many people getting scared
- * by the error message
- */
-
- /* Test 3: Check if the .rodata section is executable */
- if (rodata_test_data != 0xC3) {
- printk(KERN_ERR "test_nx: .rodata marker has invalid value\n");
- ret = -ENODEV;
- } else if (test_address(&rodata_test_data)) {
- printk(KERN_ERR "test_nx: .rodata section is executable\n");
- ret = -ENODEV;
- }
-
-#if 0
- /* Test 4: Check if the .data section of a module is executable */
- if (test_address(&test_data)) {
- printk(KERN_ERR "test_nx: .data section is executable\n");
- ret = -ENODEV;
- }
-
-#endif
- return ret;
-}
-
-static void test_exit(void)
-{
-}
-
-module_init(test_NX);
-module_exit(test_exit);
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Testcase for the NX infrastructure");
-MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
projects / linux.git / commitdiff