// SPDX-License-Identifier: GPL-2.0-or-later /* * Test cases for compiler-based stack variable zeroing via * -ftrivial-auto-var-init={zero,pattern} or CONFIG_GCC_PLUGIN_STRUCTLEAK*. * For example, see: * "Running tests with kunit_tool" at Documentation/dev-tools/kunit/start.rst * ./tools/testing/kunit/kunit.py run stackinit [--raw_output] \ * --make_option LLVM=1 \ * --kconfig_add CONFIG_INIT_STACK_ALL_ZERO=y * */ #define pr_fmt(fmt) … #include <kunit/test.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/string.h> /* Exfiltration buffer. */ #define MAX_VAR_SIZE … static u8 check_buf[MAX_VAR_SIZE]; /* Character array to trigger stack protector in all functions. */ #define VAR_BUFFER … /* Volatile mask to convince compiler to copy memory with 0xff. */ static volatile u8 forced_mask = …; /* Location and size tracking to validate fill and test are colocated. */ static void *fill_start, *target_start; static size_t fill_size, target_size; static bool stackinit_range_contains(char *haystack_start, size_t haystack_size, char *needle_start, size_t needle_size) { … } /* Whether the test is expected to fail. */ #define WANT_SUCCESS … #define XFAIL … #define DO_NOTHING_TYPE_SCALAR(var_type) … #define DO_NOTHING_TYPE_STRING(var_type) … #define DO_NOTHING_TYPE_STRUCT(var_type) … #define DO_NOTHING_RETURN_SCALAR(ptr) … #define DO_NOTHING_RETURN_STRING(ptr) … #define DO_NOTHING_RETURN_STRUCT(ptr) … #define DO_NOTHING_CALL_SCALAR(var, name) … #define DO_NOTHING_CALL_STRING(var, name) … #define DO_NOTHING_CALL_STRUCT(var, name) … #define FETCH_ARG_SCALAR(var) … #define FETCH_ARG_STRING(var) … #define FETCH_ARG_STRUCT(var) … /* * On m68k, if the leaf function test variable is longer than 8 bytes, * the start of the stack frame moves. 8 is sufficiently large to * test m68k char arrays, but leave it at 16 for other architectures. */ #ifdef CONFIG_M68K #define FILL_SIZE_STRING … #else #define FILL_SIZE_STRING … #endif #define INIT_CLONE_SCALAR … #define INIT_CLONE_STRING … #define INIT_CLONE_STRUCT … #define ZERO_CLONE_SCALAR(zero) … #define ZERO_CLONE_STRING(zero) … /* * For the struct, intentionally poison padding to see if it gets * copied out in direct assignments. * */ #define ZERO_CLONE_STRUCT(zero) … #define INIT_SCALAR_none(var_type) … #define INIT_SCALAR_zero(var_type) … #define INIT_STRING_none(var_type) … #define INIT_STRING_zero(var_type) … #define INIT_STRUCT_none(var_type) … #define INIT_STRUCT_zero(var_type) … #define __static_partial … #define __static_all … #define __dynamic_partial … #define __dynamic_all … #define __runtime_partial … #define __runtime_all … #define INIT_STRUCT_static_partial(var_type) … #define INIT_STRUCT_static_all(var_type) … #define INIT_STRUCT_dynamic_partial(var_type) … #define INIT_STRUCT_dynamic_all(var_type) … #define INIT_STRUCT_runtime_partial(var_type) … #define INIT_STRUCT_runtime_all(var_type) … #define INIT_STRUCT_assigned_static_partial(var_type) … #define INIT_STRUCT_assigned_static_all(var_type) … #define INIT_STRUCT_assigned_dynamic_partial(var_type) … #define INIT_STRUCT_assigned_dynamic_all(var_type) … #define INIT_STRUCT_assigned_copy(var_type) … /* * @name: unique string name for the test * @var_type: type to be tested for zeroing initialization * @which: is this a SCALAR, STRING, or STRUCT type? * @init_level: what kind of initialization is performed * @xfail: is this test expected to fail? */ #define DEFINE_TEST_DRIVER(name, var_type, which, xfail) … #define DEFINE_TEST(name, var_type, which, init_level, xfail) … /* Structure with no padding. */ struct test_packed { … }; /* Simple structure with padding likely to be covered by compiler. */ struct test_small_hole { … }; /* Trigger unhandled padding in a structure. */ struct test_big_hole { … } __aligned(…); struct test_trailing_hole { … }; /* Test if STRUCTLEAK is clearing structs with __user fields. */ struct test_user { … }; #define ALWAYS_PASS … #define ALWAYS_FAIL … #ifdef CONFIG_INIT_STACK_NONE #define USER_PASS … #define BYREF_PASS … #define STRONG_PASS … #elif defined(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER) #define USER_PASS … #define BYREF_PASS … #define STRONG_PASS … #elif defined(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF) #define USER_PASS … #define BYREF_PASS … #define STRONG_PASS … #else #define USER_PASS … #define BYREF_PASS … #define STRONG_PASS … #endif #define DEFINE_SCALAR_TEST(name, init, xfail) … #define DEFINE_SCALAR_TESTS(init, xfail) … #define DEFINE_STRUCT_TEST(name, init, xfail) … #define DEFINE_STRUCT_TESTS(init, xfail) … #define DEFINE_STRUCT_INITIALIZER_TESTS(base, xfail) … /* These should be fully initialized all the time! */ DEFINE_SCALAR_TESTS(zero, ALWAYS_PASS); DEFINE_STRUCT_TESTS(zero, ALWAYS_PASS); /* Struct initializers: padding may be left uninitialized. */ DEFINE_STRUCT_INITIALIZER_TESTS(static, STRONG_PASS); DEFINE_STRUCT_INITIALIZER_TESTS(dynamic, STRONG_PASS); DEFINE_STRUCT_INITIALIZER_TESTS(runtime, STRONG_PASS); DEFINE_STRUCT_INITIALIZER_TESTS(assigned_static, STRONG_PASS); DEFINE_STRUCT_INITIALIZER_TESTS(assigned_dynamic, STRONG_PASS); DEFINE_STRUCT_TESTS(assigned_copy, ALWAYS_FAIL); /* No initialization without compiler instrumentation. */ DEFINE_SCALAR_TESTS(none, STRONG_PASS); DEFINE_STRUCT_TESTS(none, BYREF_PASS); /* Initialization of members with __user attribute. */ DEFINE_TEST(user, struct test_user, STRUCT, none, USER_PASS); /* * Check two uses through a variable declaration outside either path, * which was noticed as a special case in porting earlier stack init * compiler logic. */ static int noinline __leaf_switch_none(int path, bool fill) { … } static noinline int leaf_switch_1_none(unsigned long sp, bool fill, uint64_t *arg) { … } static noinline int leaf_switch_2_none(unsigned long sp, bool fill, uint64_t *arg) { … } /* * These are expected to fail for most configurations because neither * GCC nor Clang have a way to perform initialization of variables in * non-code areas (i.e. in a switch statement before the first "case"). * https://llvm.org/pr44916 */ DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, ALWAYS_FAIL); DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, ALWAYS_FAIL); #define KUNIT_test_scalars(init) … #define KUNIT_test_structs(init) … \ static struct kunit_case stackinit_test_cases[] = …; static struct kunit_suite stackinit_test_suite = …; kunit_test_suites(…); MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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