diff options
Diffstat (limited to 'lib/test_stackinit.c')
-rw-r--r-- | lib/test_stackinit.c | 387 |
1 files changed, 0 insertions, 387 deletions
diff --git a/lib/test_stackinit.c b/lib/test_stackinit.c deleted file mode 100644 index 2d7d257a430e..000000000000 --- a/lib/test_stackinit.c +++ /dev/null @@ -1,387 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Test cases for compiler-based stack variable zeroing via future - * compiler flags or CONFIG_GCC_PLUGIN_STRUCTLEAK*. - */ -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#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 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; -} - -#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 - -#define FILL_SIZE_STRING 16 - -#define INIT_CLONE_SCALAR /**/ -#define INIT_CLONE_STRING [FILL_SIZE_STRING] -#define INIT_CLONE_STRUCT /**/ - -#define INIT_SCALAR_none /**/ -#define INIT_SCALAR_zero = 0 - -#define INIT_STRING_none [FILL_SIZE_STRING] /**/ -#define INIT_STRING_zero [FILL_SIZE_STRING] = { } - -#define INIT_STRUCT_none /**/ -#define INIT_STRUCT_zero = { } -#define INIT_STRUCT_static_partial = { .two = 0, } -#define INIT_STRUCT_static_all = { .one = arg->one, \ - .two = arg->two, \ - .three = arg->three, \ - .four = arg->four, \ - } -#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 INIT_STRUCT_runtime_partial ; \ - var.two = 0 -#define INIT_STRUCT_runtime_all ; \ - var.one = 0; \ - var.two = 0; \ - var.three = 0; \ - memset(&var.four, 0, \ - sizeof(var.four)) - -/* - * @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 - */ -#define DEFINE_TEST_DRIVER(name, var_type, which) \ -/* Returns 0 on success, 1 on failure. */ \ -static noinline __init int test_ ## name (void) \ -{ \ - 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. */ \ - memset(&zero, 0x00, sizeof(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); \ - if (sum) { \ - pr_err(#name ": leaf fill was not 0xFF!?\n"); \ - return 1; \ - } \ - /* 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)); \ - \ - /* Validate that compiler lined up fill and target. */ \ - if (!range_contains(fill_start, fill_size, \ - target_start, target_size)) { \ - pr_err(#name ": stack fill missed target!?\n"); \ - pr_err(#name ": fill %zu wide\n", fill_size); \ - pr_err(#name ": target offset by %d\n", \ - (int)((ssize_t)(uintptr_t)fill_start - \ - (ssize_t)(uintptr_t)target_start)); \ - return 1; \ - } \ - \ - /* 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) \ - pr_info(#name " ok\n"); \ - else \ - pr_warn(#name " FAIL (uninit bytes: %d)\n", \ - sum); \ - \ - return (sum != 0); \ -} -#define DEFINE_TEST(name, var_type, which, init_level) \ -/* no-op to force compiler into ignoring "uninitialized" vars */\ -static noinline __init 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 __init int leaf_ ## name(unsigned long sp, \ - bool fill, \ - var_type *arg) \ -{ \ - char buf[VAR_BUFFER]; \ - var_type var INIT_ ## which ## _ ## init_level; \ - \ - 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) - -/* 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; -}; - -/* Try to trigger unhandled padding in a structure. */ -struct test_aligned { - u32 internal1; - u64 internal2; -} __aligned(64); - -struct test_big_hole { - u8 one; - u8 two; - u8 three; - /* 61 byte padding hole here. */ - struct test_aligned four; -} __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 DEFINE_SCALAR_TEST(name, init) \ - DEFINE_TEST(name ## _ ## init, name, SCALAR, init) - -#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_STRUCT_TEST(name, init) \ - DEFINE_TEST(name ## _ ## init, \ - struct test_ ## name, STRUCT, init) - -#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) - -/* 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); -/* No initialization without compiler instrumentation. */ -DEFINE_SCALAR_TESTS(none); -DEFINE_STRUCT_TESTS(none); -DEFINE_TEST(user, struct test_user, STRUCT, none); - -/* - * 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) { - uint64_t var; - - 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 = 5; - return var & forced_mask; - } - return 0; -} - -static noinline __init int leaf_switch_1_none(unsigned long sp, bool fill, - uint64_t *arg) -{ - return __leaf_switch_none(1, fill); -} - -static noinline __init int leaf_switch_2_none(unsigned long sp, bool fill, - uint64_t *arg) -{ - return __leaf_switch_none(2, fill); -} - -DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR); -DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR); - -static int __init test_stackinit_init(void) -{ - unsigned int failures = 0; - -#define test_scalars(init) do { \ - failures += test_u8_ ## init (); \ - failures += test_u16_ ## init (); \ - failures += test_u32_ ## init (); \ - failures += test_u64_ ## init (); \ - failures += test_char_array_ ## init (); \ - } while (0) - -#define test_structs(init) do { \ - failures += test_small_hole_ ## init (); \ - failures += test_big_hole_ ## init (); \ - failures += test_trailing_hole_ ## init (); \ - failures += test_packed_ ## init (); \ - } while (0) - - /* These are explicitly initialized and should always pass. */ - test_scalars(zero); - test_structs(zero); - /* Padding here appears to be accidentally always initialized? */ - test_structs(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); - - /* STRUCTLEAK_BYREF_ALL should cover everything from here down. */ - test_scalars(none); - failures += test_switch_1_none(); - failures += test_switch_2_none(); - - /* STRUCTLEAK_BYREF should cover from here down. */ - test_structs(none); - - /* STRUCTLEAK will only cover this. */ - failures += test_user(); - - if (failures == 0) - pr_info("all tests passed!\n"); - else - pr_err("failures: %u\n", failures); - - return failures ? -EINVAL : 0; -} -module_init(test_stackinit_init); - -static void __exit test_stackinit_exit(void) -{ } -module_exit(test_stackinit_exit); - -MODULE_LICENSE("GPL"); |