| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Kees Cook | 1175 | 99.32% | 8 | 66.67% |
| Jeff Johnson | 5 | 0.42% | 1 | 8.33% |
| Tales L. da Aparecida | 1 | 0.08% | 1 | 8.33% |
| Dan J Williams | 1 | 0.08% | 1 | 8.33% |
| Nathan Chancellor | 1 | 0.08% | 1 | 8.33% |
| Total | 1183 | 12 |
// 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) KBUILD_MODNAME ": " 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 128 static u8 check_buf[MAX_VAR_SIZE]; /* Character array to trigger stack protector in all functions. */ #define VAR_BUFFER 32 /* Volatile mask to convince compiler to copy memory with 0xff. */ static volatile u8 forced_mask = 0xff; /* 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) { if (needle_start >= haystack_start && needle_start + needle_size <= haystack_start + haystack_size) return true; return false; } /* Whether the test is expected to fail. */ #define WANT_SUCCESS 0 #define XFAIL 1 #define DO_NOTHING_TYPE_SCALAR(var_type) var_type #define DO_NOTHING_TYPE_STRING(var_type) void #define DO_NOTHING_TYPE_STRUCT(var_type) void #define DO_NOTHING_RETURN_SCALAR(ptr) *(ptr) #define DO_NOTHING_RETURN_STRING(ptr) /**/ #define DO_NOTHING_RETURN_STRUCT(ptr) /**/ #define DO_NOTHING_CALL_SCALAR(var, name) \ (var) = do_nothing_ ## name(&(var)) #define DO_NOTHING_CALL_STRING(var, name) \ do_nothing_ ## name(var) #define DO_NOTHING_CALL_STRUCT(var, name) \ do_nothing_ ## name(&(var)) #define FETCH_ARG_SCALAR(var) &var #define FETCH_ARG_STRING(var) var #define FETCH_ARG_STRUCT(var) &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 8 #else #define FILL_SIZE_STRING 16 #endif #define INIT_CLONE_SCALAR /**/ #define INIT_CLONE_STRING [FILL_SIZE_STRING] #define INIT_CLONE_STRUCT /**/ #define ZERO_CLONE_SCALAR(zero) memset(&(zero), 0x00, sizeof(zero)) #define ZERO_CLONE_STRING(zero) memset(&(zero), 0x00, sizeof(zero)) /* * For the struct, intentionally poison padding to see if it gets * copied out in direct assignments. * */ #define ZERO_CLONE_STRUCT(zero) \ do { \ memset(&(zero), 0xFF, sizeof(zero)); \ zero.one = 0; \ zero.two = 0; \ zero.three = 0; \ zero.four = 0; \ } while (0) #define INIT_SCALAR_none(var_type) /**/ #define INIT_SCALAR_zero(var_type) = 0 #define INIT_STRING_none(var_type) [FILL_SIZE_STRING] /**/ #define INIT_STRING_zero(var_type) [FILL_SIZE_STRING] = { } #define INIT_STRUCT_none(var_type) /**/ #define INIT_STRUCT_zero(var_type) = { } #define __static_partial { .two = 0, } #define __static_all { .one = 0, \ .two = 0, \ .three = 0, \ .four = 0, \ } #define __dynamic_partial { .two = arg->two, } #define __dynamic_all { .one = arg->one, \ .two = arg->two, \ .three = arg->three, \ .four = arg->four, \ } #define __runtime_partial var.two = 0 #define __runtime_all var.one = 0; \ var.two = 0; \ var.three = 0; \ var.four = 0 #define INIT_STRUCT_static_partial(var_type) \ = __static_partial #define INIT_STRUCT_static_all(var_type) \ = __static_all #define INIT_STRUCT_dynamic_partial(var_type) \ = __dynamic_partial #define INIT_STRUCT_dynamic_all(var_type) \ = __dynamic_all #define INIT_STRUCT_runtime_partial(var_type) \ ; __runtime_partial #define INIT_STRUCT_runtime_all(var_type) \ ; __runtime_all #define INIT_STRUCT_assigned_static_partial(var_type) \ ; var = (var_type)__static_partial #define INIT_STRUCT_assigned_static_all(var_type) \ ; var = (var_type)__static_all #define INIT_STRUCT_assigned_dynamic_partial(var_type) \ ; var = (var_type)__dynamic_partial #define INIT_STRUCT_assigned_dynamic_all(var_type) \ ; var = (var_type)__dynamic_all #define INIT_STRUCT_assigned_copy(var_type) \ ; var = *(arg) /* * @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) \ /* Returns 0 on success, 1 on failure. */ \ static noinline void test_ ## name (struct kunit *test) \ { \ var_type zero INIT_CLONE_ ## which; \ int ignored; \ u8 sum = 0, i; \ \ /* Notice when a new test is larger than expected. */ \ BUILD_BUG_ON(sizeof(zero) > MAX_VAR_SIZE); \ \ /* Fill clone type with zero for per-field init. */ \ ZERO_CLONE_ ## which(zero); \ /* Clear entire check buffer for 0xFF overlap test. */ \ memset(check_buf, 0x00, sizeof(check_buf)); \ /* Fill stack with 0xFF. */ \ ignored = leaf_ ##name((unsigned long)&ignored, 1, \ FETCH_ARG_ ## which(zero)); \ /* Verify all bytes overwritten with 0xFF. */ \ for (sum = 0, i = 0; i < target_size; i++) \ sum += (check_buf[i] != 0xFF); \ /* Clear entire check buffer for later bit tests. */ \ memset(check_buf, 0x00, sizeof(check_buf)); \ /* Extract stack-defined variable contents. */ \ ignored = leaf_ ##name((unsigned long)&ignored, 0, \ FETCH_ARG_ ## which(zero)); \ /* \ * Delay the sum test to here to do as little as \ * possible between the two leaf function calls. \ */ \ KUNIT_ASSERT_EQ_MSG(test, sum, 0, \ "leaf fill was not 0xFF!?\n"); \ \ /* Validate that compiler lined up fill and target. */ \ KUNIT_ASSERT_TRUE_MSG(test, \ stackinit_range_contains(fill_start, fill_size, \ target_start, target_size), \ "stackframe was not the same between calls!? " \ "(fill %zu wide, target offset by %d)\n", \ fill_size, \ (int)((ssize_t)(uintptr_t)fill_start - \ (ssize_t)(uintptr_t)target_start)); \ \ /* Look for any bytes still 0xFF in check region. */ \ for (sum = 0, i = 0; i < target_size; i++) \ sum += (check_buf[i] == 0xFF); \ \ if (sum != 0 && xfail) \ kunit_skip(test, \ "XFAIL uninit bytes: %d\n", \ sum); \ KUNIT_ASSERT_EQ_MSG(test, sum, 0, \ "uninit bytes: %d\n", sum); \ } #define DEFINE_TEST(name, var_type, which, init_level, xfail) \ /* no-op to force compiler into ignoring "uninitialized" vars */\ static noinline DO_NOTHING_TYPE_ ## which(var_type) \ do_nothing_ ## name(var_type *ptr) \ { \ /* Will always be true, but compiler doesn't know. */ \ if ((unsigned long)ptr > 0x2) \ return DO_NOTHING_RETURN_ ## which(ptr); \ else \ return DO_NOTHING_RETURN_ ## which(ptr + 1); \ } \ static noinline int leaf_ ## name(unsigned long sp, bool fill, \ var_type *arg) \ { \ char buf[VAR_BUFFER]; \ var_type var \ INIT_ ## which ## _ ## init_level(var_type); \ \ target_start = &var; \ target_size = sizeof(var); \ /* \ * Keep this buffer around to make sure we've got a \ * stack frame of SOME kind... \ */ \ memset(buf, (char)(sp & 0xff), sizeof(buf)); \ /* Fill variable with 0xFF. */ \ if (fill) { \ fill_start = &var; \ fill_size = sizeof(var); \ memset(fill_start, \ (char)((sp & 0xff) | forced_mask), \ fill_size); \ } \ \ /* Silence "never initialized" warnings. */ \ DO_NOTHING_CALL_ ## which(var, name); \ \ /* Exfiltrate "var". */ \ memcpy(check_buf, target_start, target_size); \ \ return (int)buf[0] | (int)buf[sizeof(buf) - 1]; \ } \ DEFINE_TEST_DRIVER(name, var_type, which, xfail) /* Structure with no padding. */ struct test_packed { unsigned long one; unsigned long two; unsigned long three; unsigned long four; }; /* Simple structure with padding likely to be covered by compiler. */ struct test_small_hole { size_t one; char two; /* 3 byte padding hole here. */ int three; unsigned long four; }; /* Trigger unhandled padding in a structure. */ struct test_big_hole { u8 one; u8 two; u8 three; /* 61 byte padding hole here. */ u8 four __aligned(64); } __aligned(64); struct test_trailing_hole { char *one; char *two; char *three; char four; /* "sizeof(unsigned long) - 1" byte padding hole here. */ }; /* Test if STRUCTLEAK is clearing structs with __user fields. */ struct test_user { u8 one; unsigned long two; char __user *three; unsigned long four; }; #define ALWAYS_PASS WANT_SUCCESS #define ALWAYS_FAIL XFAIL #ifdef CONFIG_INIT_STACK_NONE # define USER_PASS XFAIL # define BYREF_PASS XFAIL # define STRONG_PASS XFAIL #elif defined(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER) # define USER_PASS WANT_SUCCESS # define BYREF_PASS XFAIL # define STRONG_PASS XFAIL #elif defined(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF) # define USER_PASS WANT_SUCCESS # define BYREF_PASS WANT_SUCCESS # define STRONG_PASS XFAIL #else # define USER_PASS WANT_SUCCESS # define BYREF_PASS WANT_SUCCESS # define STRONG_PASS WANT_SUCCESS #endif #define DEFINE_SCALAR_TEST(name, init, xfail) \ DEFINE_TEST(name ## _ ## init, name, SCALAR, \ init, xfail) #define DEFINE_SCALAR_TESTS(init, xfail) \ DEFINE_SCALAR_TEST(u8, init, xfail); \ DEFINE_SCALAR_TEST(u16, init, xfail); \ DEFINE_SCALAR_TEST(u32, init, xfail); \ DEFINE_SCALAR_TEST(u64, init, xfail); \ DEFINE_TEST(char_array_ ## init, unsigned char, \ STRING, init, xfail) #define DEFINE_STRUCT_TEST(name, init, xfail) \ DEFINE_TEST(name ## _ ## init, \ struct test_ ## name, STRUCT, init, \ xfail) #define DEFINE_STRUCT_TESTS(init, xfail) \ DEFINE_STRUCT_TEST(small_hole, init, xfail); \ DEFINE_STRUCT_TEST(big_hole, init, xfail); \ DEFINE_STRUCT_TEST(trailing_hole, init, xfail); \ DEFINE_STRUCT_TEST(packed, init, xfail) #define DEFINE_STRUCT_INITIALIZER_TESTS(base, xfail) \ DEFINE_STRUCT_TESTS(base ## _ ## partial, \ xfail); \ DEFINE_STRUCT_TESTS(base ## _ ## all, 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) { switch (path) { /* * This is intentionally unreachable. To silence the * warning, build with -Wno-switch-unreachable */ uint64_t var[10]; case 1: target_start = &var; target_size = sizeof(var); if (fill) { fill_start = &var; fill_size = sizeof(var); memset(fill_start, forced_mask | 0x55, fill_size); } memcpy(check_buf, target_start, target_size); break; case 2: target_start = &var; target_size = sizeof(var); if (fill) { fill_start = &var; fill_size = sizeof(var); memset(fill_start, forced_mask | 0xaa, fill_size); } memcpy(check_buf, target_start, target_size); break; default: var[1] = 5; return var[1] & forced_mask; } return 0; } static noinline int leaf_switch_1_none(unsigned long sp, bool fill, uint64_t *arg) { return __leaf_switch_none(1, fill); } static noinline int leaf_switch_2_none(unsigned long sp, bool fill, uint64_t *arg) { return __leaf_switch_none(2, fill); } /* * 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) \ KUNIT_CASE(test_u8_ ## init), \ KUNIT_CASE(test_u16_ ## init), \ KUNIT_CASE(test_u32_ ## init), \ KUNIT_CASE(test_u64_ ## init), \ KUNIT_CASE(test_char_array_ ## init) #define KUNIT_test_structs(init) \ KUNIT_CASE(test_small_hole_ ## init), \ KUNIT_CASE(test_big_hole_ ## init), \ KUNIT_CASE(test_trailing_hole_ ## init),\ KUNIT_CASE(test_packed_ ## init) \ static struct kunit_case stackinit_test_cases[] = { /* These are explicitly initialized and should always pass. */ KUNIT_test_scalars(zero), KUNIT_test_structs(zero), /* Padding here appears to be accidentally always initialized? */ KUNIT_test_structs(dynamic_partial), KUNIT_test_structs(assigned_dynamic_partial), /* Padding initialization depends on compiler behaviors. */ KUNIT_test_structs(static_partial), KUNIT_test_structs(static_all), KUNIT_test_structs(dynamic_all), KUNIT_test_structs(runtime_partial), KUNIT_test_structs(runtime_all), KUNIT_test_structs(assigned_static_partial), KUNIT_test_structs(assigned_static_all), KUNIT_test_structs(assigned_dynamic_all), /* Everything fails this since it effectively performs a memcpy(). */ KUNIT_test_structs(assigned_copy), /* STRUCTLEAK_BYREF_ALL should cover everything from here down. */ KUNIT_test_scalars(none), KUNIT_CASE(test_switch_1_none), KUNIT_CASE(test_switch_2_none), /* STRUCTLEAK_BYREF should cover from here down. */ KUNIT_test_structs(none), /* STRUCTLEAK will only cover this. */ KUNIT_CASE(test_user), {} }; static struct kunit_suite stackinit_test_suite = { .name = "stackinit", .test_cases = stackinit_test_cases, }; kunit_test_suites(&stackinit_test_suite); MODULE_DESCRIPTION("Test cases for compiler-based stack variable zeroing"); MODULE_LICENSE("GPL");
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