1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Runtime test cases for CONFIG_FORTIFY_SOURCE that aren't expected to
4 * Oops the kernel on success. (For those, see drivers/misc/lkdtm/fortify.c)
5 *
6 * For corner cases with UBSAN, try testing with:
7 *
8 * ./tools/testing/kunit/kunit.py run --arch=x86_64 \
9 * --kconfig_add CONFIG_FORTIFY_SOURCE=y \
10 * --kconfig_add CONFIG_UBSAN=y \
11 * --kconfig_add CONFIG_UBSAN_TRAP=y \
12 * --kconfig_add CONFIG_UBSAN_BOUNDS=y \
13 * --kconfig_add CONFIG_UBSAN_LOCAL_BOUNDS=y \
14 * --make_options LLVM=1 fortify
15 */
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18 #include <kunit/test.h>
19 #include <linux/string.h>
20
21 static const char array_of_10[] = "this is 10";
22 static const char *ptr_of_11 = "this is 11!";
23 static char array_unknown[] = "compiler thinks I might change";
24
known_sizes_test(struct kunit * test)25 static void known_sizes_test(struct kunit *test)
26 {
27 KUNIT_EXPECT_EQ(test, __compiletime_strlen("88888888"), 8);
28 KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_of_10), 10);
29 KUNIT_EXPECT_EQ(test, __compiletime_strlen(ptr_of_11), 11);
30
31 KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_unknown), SIZE_MAX);
32 /* Externally defined and dynamically sized string pointer: */
33 KUNIT_EXPECT_EQ(test, __compiletime_strlen(test->name), SIZE_MAX);
34 }
35
36 /* This is volatile so the optimizer can't perform DCE below. */
37 static volatile int pick;
38
39 /* Not inline to keep optimizer from figuring out which string we want. */
want_minus_one(int pick)40 static noinline size_t want_minus_one(int pick)
41 {
42 const char *str;
43
44 switch (pick) {
45 case 1:
46 str = "4444";
47 break;
48 case 2:
49 str = "333";
50 break;
51 default:
52 str = "1";
53 break;
54 }
55 return __compiletime_strlen(str);
56 }
57
control_flow_split_test(struct kunit * test)58 static void control_flow_split_test(struct kunit *test)
59 {
60 KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX);
61 }
62
63 static struct kunit_case fortify_test_cases[] = {
64 KUNIT_CASE(known_sizes_test),
65 KUNIT_CASE(control_flow_split_test),
66 {}
67 };
68
69 static struct kunit_suite fortify_test_suite = {
70 .name = "fortify",
71 .test_cases = fortify_test_cases,
72 };
73
74 kunit_test_suite(fortify_test_suite);
75
76 MODULE_LICENSE("GPL");
77
