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
10 #define STACKSIZE 2048
11 #define THREAD_COUNT 64
12 #define VERBOSE 0
13
14 void *last_sp = (void *)0xFFFFFFFF;
15 volatile unsigned int changed;
16
17 /*
18 * The `alternate_thread` function deliberately makes use of a dangling pointer
19 * in order to test stack randomisation.
20 */
21 #if defined(__GNUC__)
22 #pragma GCC diagnostic push
23 #pragma GCC diagnostic ignored "-Wpragmas"
24 #pragma GCC diagnostic ignored "-Wdangling-pointer"
25 #endif
26
alternate_thread(void * p1,void * p2,void * p3)27 void alternate_thread(void *p1, void *p2, void *p3)
28 {
29 ARG_UNUSED(p1);
30 ARG_UNUSED(p2);
31 ARG_UNUSED(p3);
32
33 int i;
34 void *sp_val;
35
36 /* If the stack isn't being randomized then sp_val will never change */
37 sp_val = &i;
38
39 #if VERBOSE
40 printk("stack pointer: %p last: %p\n", sp_val, last_sp);
41 #endif
42
43 if (last_sp != (void *)0xFFFFFFFF && sp_val != last_sp) {
44 changed++;
45 }
46 last_sp = sp_val;
47 }
48
49 #if defined(__GNUC__)
50 #pragma GCC diagnostic pop
51 #endif
52
53 K_THREAD_STACK_DEFINE(alt_thread_stack_area, STACKSIZE);
54 static struct k_thread alt_thread_data;
55
56 /**
57 * @brief Test stack pointer randomization
58 *
59 * @ingroup kernel_memprotect_tests
60 *
61 */
ZTEST(stack_pointer_randomness,test_stack_pt_randomization)62 ZTEST(stack_pointer_randomness, test_stack_pt_randomization)
63 {
64 int i, sp_changed;
65 int old_prio = k_thread_priority_get(k_current_get());
66
67 /* Set preemptable priority */
68 k_thread_priority_set(k_current_get(), K_PRIO_PREEMPT(1));
69
70 printk("Test Stack pointer randomization\n");
71
72 /* Start thread */
73 for (i = 0; i < THREAD_COUNT; i++) {
74 k_thread_create(&alt_thread_data, alt_thread_stack_area,
75 STACKSIZE, alternate_thread,
76 NULL, NULL, NULL, K_HIGHEST_THREAD_PRIO, 0,
77 K_NO_WAIT);
78 k_sleep(K_MSEC(10));
79 }
80
81
82 printk("stack pointer changed %d times out of %d tests\n",
83 changed, THREAD_COUNT);
84
85 sp_changed = changed;
86 zassert_not_equal(sp_changed, 0, "Stack pointer is not randomized");
87
88 /* Restore priority */
89 k_thread_priority_set(k_current_get(), old_prio);
90 }
91
92 ZTEST_SUITE(stack_pointer_randomness, NULL, NULL,
93 ztest_simple_1cpu_before, ztest_simple_1cpu_after, NULL);
94
