lib/fortify_kunit.c

   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
  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. */
  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
  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");