diff options
| -rw-r--r-- | arch/x86/Kconfig.debug | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/test_nx.c | 173 |
3 files changed, 0 insertions, 182 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 67eec55093a5..783099f2ac72 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -120,14 +120,6 @@ config DEBUG_SET_MODULE_RONX against certain classes of kernel exploits. If in doubt, say "N". -config DEBUG_NX_TEST - tristate "Testcase for the NX non-executable stack feature" - depends on DEBUG_KERNEL && m - ---help--- - This option enables a testcase for the CPU NX capability - and the software setup of this feature. - If in doubt, say "N" - config DOUBLEFAULT default y bool "Enable doublefault exception handler" if EXPERT diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 581386c7e429..bdcdb3b3a219 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -101,7 +101,6 @@ obj-$(CONFIG_APB_TIMER) += apb_timer.o obj-$(CONFIG_AMD_NB) += amd_nb.o obj-$(CONFIG_DEBUG_RODATA_TEST) += test_rodata.o -obj-$(CONFIG_DEBUG_NX_TEST) += test_nx.o obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o obj-$(CONFIG_KVM_GUEST) += kvm.o kvmclock.o diff --git a/arch/x86/kernel/test_nx.c b/arch/x86/kernel/test_nx.c deleted file mode 100644 index a3b875c9e6af..000000000000 --- a/arch/x86/kernel/test_nx.c +++ /dev/null @@ -1,173 +0,0 @@ -/* - * 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>"); |
