From a8fc576d4af2f23a87a586424252df97f0ad0b06 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 23 Jul 2021 15:19:33 -0700 Subject: [PATCH] lib/test_stackinit: Add assigned initializers Add whole-variable assignments of cast static initializers. These appear to currently behave like the direct initializers, but best to check them too. For example: struct test_big_hole var; var = (struct test_big_hole){ .one = arg->one, .two= arg->two, .three = arg->three, .four = arg->four }; Additionally adds a test for whole-object assignment, which is expected to fail since it usually falls back to a memcpy(): var = *arg; Suggested-by: Arnd Bergmann Link: https://lore.kernel.org/lkml/CAK8P3a20SEoYCrp3jOK32oZc9OkiPv+1KTjNZ2GxLbHpY4WexQ@mail.gmail.com Cc: Ard Biesheuvel Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210723221933.3431999-4-keescook@chromium.org --- lib/test_stackinit.c | 169 +++++++++++++++++++++++++++++-------------- 1 file changed, 114 insertions(+), 55 deletions(-) diff --git a/lib/test_stackinit.c b/lib/test_stackinit.c index 70bcc1e5112c..a3c74e6a21ff 100644 --- a/lib/test_stackinit.c +++ b/lib/test_stackinit.c @@ -95,6 +95,10 @@ static bool range_contains(char *haystack_start, size_t haystack_size, 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 @@ -120,34 +124,74 @@ static bool range_contains(char *haystack_start, size_t haystack_size, #define INIT_CLONE_STRING [FILL_SIZE_STRING] #define INIT_CLONE_STRUCT /**/ -#define INIT_SCALAR_none /**/ -#define INIT_SCALAR_zero = 0 +#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_STRING_none [FILL_SIZE_STRING] /**/ -#define INIT_STRING_zero [FILL_SIZE_STRING] = { } +#define INIT_SCALAR_none(var_type) /**/ +#define INIT_SCALAR_zero(var_type) = 0 -#define INIT_STRUCT_none /**/ -#define INIT_STRUCT_zero = { } -#define INIT_STRUCT_static_partial = { .two = 0, } -#define INIT_STRUCT_static_all = { .one = 0, \ - .two = 0, \ - .three = 0, \ - .four = 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 INIT_STRUCT_dynamic_partial = { .two = arg->two, } -#define INIT_STRUCT_dynamic_all = { .one = arg->one, \ - .two = arg->two, \ - .three = arg->three, \ - .four = arg->four, \ +#define __dynamic_partial { .two = arg->two, } +#define __dynamic_all { .one = arg->one, \ + .two = arg->two, \ + .three = arg->three, \ + .four = arg->four, \ } -#define INIT_STRUCT_runtime_partial ; \ - var.two = 0 -#define INIT_STRUCT_runtime_all ; \ - var.one = 0; \ +#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 @@ -167,7 +211,7 @@ static noinline __init int test_ ## name (void) \ BUILD_BUG_ON(sizeof(zero) > MAX_VAR_SIZE); \ \ /* Fill clone type with zero for per-field init. */ \ - memset(&zero, 0x00, sizeof(zero)); \ + ZERO_CLONE_ ## which(zero); \ /* Clear entire check buffer for 0xFF overlap test. */ \ memset(check_buf, 0x00, sizeof(check_buf)); \ /* Fill stack with 0xFF. */ \ @@ -210,7 +254,7 @@ static noinline __init int test_ ## name (void) \ return (xfail) ? 0 : 1; \ } \ } -#define DEFINE_TEST(name, var_type, which, init_level) \ +#define DEFINE_TEST(name, var_type, which, init_level, xfail) \ /* no-op to force compiler into ignoring "uninitialized" vars */\ static noinline __init DO_NOTHING_TYPE_ ## which(var_type) \ do_nothing_ ## name(var_type *ptr) \ @@ -226,7 +270,8 @@ static noinline __init int leaf_ ## name(unsigned long sp, \ var_type *arg) \ { \ char buf[VAR_BUFFER]; \ - var_type var INIT_ ## which ## _ ## init_level; \ + var_type var \ + INIT_ ## which ## _ ## init_level(var_type); \ \ target_start = &var; \ target_size = sizeof(var); \ @@ -252,7 +297,7 @@ static noinline __init int leaf_ ## name(unsigned long sp, \ \ return (int)buf[0] | (int)buf[sizeof(buf) - 1]; \ } \ -DEFINE_TEST_DRIVER(name, var_type, which, 0) +DEFINE_TEST_DRIVER(name, var_type, which, xfail) /* Structure with no padding. */ struct test_packed { @@ -296,42 +341,50 @@ struct test_user { unsigned long four; }; -#define DEFINE_SCALAR_TEST(name, init) \ - DEFINE_TEST(name ## _ ## init, name, SCALAR, init) +#define DEFINE_SCALAR_TEST(name, init, xfail) \ + DEFINE_TEST(name ## _ ## init, name, SCALAR, \ + init, xfail) -#define DEFINE_SCALAR_TESTS(init) \ - DEFINE_SCALAR_TEST(u8, init); \ - DEFINE_SCALAR_TEST(u16, init); \ - DEFINE_SCALAR_TEST(u32, init); \ - DEFINE_SCALAR_TEST(u64, init); \ - DEFINE_TEST(char_array_ ## init, unsigned char, STRING, init) +#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) \ +#define DEFINE_STRUCT_TEST(name, init, xfail) \ DEFINE_TEST(name ## _ ## init, \ - struct test_ ## name, STRUCT, init) + struct test_ ## name, STRUCT, init, \ + xfail) -#define DEFINE_STRUCT_TESTS(init) \ - DEFINE_STRUCT_TEST(small_hole, init); \ - DEFINE_STRUCT_TEST(big_hole, init); \ - DEFINE_STRUCT_TEST(trailing_hole, init); \ - DEFINE_STRUCT_TEST(packed, init) +#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) \ + DEFINE_STRUCT_TESTS(base ## _ ## partial, \ + WANT_SUCCESS); \ + DEFINE_STRUCT_TESTS(base ## _ ## all, \ + WANT_SUCCESS) /* These should be fully initialized all the time! */ -DEFINE_SCALAR_TESTS(zero); -DEFINE_STRUCT_TESTS(zero); -/* Static initialization: padding may be left uninitialized. */ -DEFINE_STRUCT_TESTS(static_partial); -DEFINE_STRUCT_TESTS(static_all); -/* Dynamic initialization: padding may be left uninitialized. */ -DEFINE_STRUCT_TESTS(dynamic_partial); -DEFINE_STRUCT_TESTS(dynamic_all); -/* Runtime initialization: padding may be left uninitialized. */ -DEFINE_STRUCT_TESTS(runtime_partial); -DEFINE_STRUCT_TESTS(runtime_all); +DEFINE_SCALAR_TESTS(zero, WANT_SUCCESS); +DEFINE_STRUCT_TESTS(zero, WANT_SUCCESS); +/* Struct initializers: padding may be left uninitialized. */ +DEFINE_STRUCT_INITIALIZER_TESTS(static); +DEFINE_STRUCT_INITIALIZER_TESTS(dynamic); +DEFINE_STRUCT_INITIALIZER_TESTS(runtime); +DEFINE_STRUCT_INITIALIZER_TESTS(assigned_static); +DEFINE_STRUCT_INITIALIZER_TESTS(assigned_dynamic); +DEFINE_STRUCT_TESTS(assigned_copy, XFAIL); /* No initialization without compiler instrumentation. */ -DEFINE_SCALAR_TESTS(none); -DEFINE_STRUCT_TESTS(none); -DEFINE_TEST(user, struct test_user, STRUCT, none); +DEFINE_SCALAR_TESTS(none, WANT_SUCCESS); +DEFINE_STRUCT_TESTS(none, WANT_SUCCESS); +/* Initialization of members with __user attribute. */ +DEFINE_TEST(user, struct test_user, STRUCT, none, WANT_SUCCESS); /* * Check two uses through a variable declaration outside either path, @@ -394,8 +447,8 @@ static noinline __init int leaf_switch_2_none(unsigned long sp, bool fill, * non-code areas (i.e. in a switch statement before the first "case"). * https://bugs.llvm.org/show_bug.cgi?id=44916 */ -DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, 1); -DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, 1); +DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, XFAIL); +DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, XFAIL); static int __init test_stackinit_init(void) { @@ -421,12 +474,18 @@ static int __init test_stackinit_init(void) test_structs(zero); /* Padding here appears to be accidentally always initialized? */ test_structs(dynamic_partial); + test_structs(assigned_dynamic_partial); /* Padding initialization depends on compiler behaviors. */ test_structs(static_partial); test_structs(static_all); test_structs(dynamic_all); test_structs(runtime_partial); test_structs(runtime_all); + test_structs(assigned_static_partial); + test_structs(assigned_static_all); + test_structs(assigned_dynamic_all); + /* Everything fails this since it effectively performs a memcpy(). */ + test_structs(assigned_copy); /* STRUCTLEAK_BYREF_ALL should cover everything from here down. */ test_scalars(none);