1 /*
2 * Copyright (c) 2018 Intel Corporation
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/ztest.h>
8 #include <zephyr/kernel.h>
9 #include <zephyr/test_toolchain.h>
10
11 #define STACKSIZE 2048
12 #define THREAD_COUNT 64
13 #define VERBOSE 0
14
15 void *last_sp = (void *)0xFFFFFFFF;
16 volatile unsigned int changed;
17
18 /*
19 * The `alternate_thread` function deliberately makes use of a dangling pointer
20 * in order to test stack randomisation.
21 */
TOOLCHAIN_DISABLE_GCC_WARNING(TOOLCHAIN_WARNING_DANGLING_POINTER)22 TOOLCHAIN_DISABLE_GCC_WARNING(TOOLCHAIN_WARNING_DANGLING_POINTER)
23
24 void alternate_thread(void *p1, void *p2, void *p3)
25 {
26 ARG_UNUSED(p1);
27 ARG_UNUSED(p2);
28 ARG_UNUSED(p3);
29
30 int i;
31 void *sp_val;
32
33 /* If the stack isn't being randomized then sp_val will never change */
34 sp_val = &i;
35
36 #if VERBOSE
37 printk("stack pointer: %p last: %p\n", sp_val, last_sp);
38 #endif
39
40 if (last_sp != (void *)0xFFFFFFFF && sp_val != last_sp) {
41 changed++;
42 }
43 last_sp = sp_val;
44 }
45
46 TOOLCHAIN_ENABLE_GCC_WARNING(TOOLCHAIN_WARNING_DANGLING_POINTER)
47
48 K_THREAD_STACK_DEFINE(alt_thread_stack_area, STACKSIZE);
49 static struct k_thread alt_thread_data;
50
51 /**
52 * @brief Test stack pointer randomization
53 *
54 * @ingroup kernel_memprotect_tests
55 *
56 */
ZTEST(stack_pointer_randomness,test_stack_pt_randomization)57 ZTEST(stack_pointer_randomness, test_stack_pt_randomization)
58 {
59 int i, sp_changed;
60 int old_prio = k_thread_priority_get(k_current_get());
61
62 /* Set preemptable priority */
63 k_thread_priority_set(k_current_get(), K_PRIO_PREEMPT(1));
64
65 printk("Test Stack pointer randomization\n");
66
67 /* Start thread */
68 for (i = 0; i < THREAD_COUNT; i++) {
69 k_thread_create(&alt_thread_data, alt_thread_stack_area,
70 STACKSIZE, alternate_thread,
71 NULL, NULL, NULL, K_HIGHEST_THREAD_PRIO, 0,
72 K_NO_WAIT);
73 k_sleep(K_MSEC(10));
74 }
75
76
77 printk("stack pointer changed %d times out of %d tests\n",
78 changed, THREAD_COUNT);
79
80 sp_changed = changed;
81 zassert_not_equal(sp_changed, 0, "Stack pointer is not randomized");
82
83 /* Restore priority */
84 k_thread_priority_set(k_current_get(), old_prio);
85 }
86
87 ZTEST_SUITE(stack_pointer_randomness, NULL, NULL,
88 ztest_simple_1cpu_before, ztest_simple_1cpu_after, NULL);
89
