// SPDX-License-Identifier: GPL-2.0-only /* * * Copyright (c) 2014 Samsung Electronics Co., Ltd. * Author: Andrey Ryabinin <a.ryabinin@samsung.com> */ #include <linux/bitops.h> #include <linux/delay.h> #include <linux/kasan.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/module.h> #include <linux/printk.h> #include <linux/random.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/uaccess.h> #include <linux/io.h> #include <linux/vmalloc.h> #include <asm/page.h> #include <kunit/test.h> #include "../mm/kasan/kasan.h" #define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE) /* * Some tests use these global variables to store return values from function * calls that could otherwise be eliminated by the compiler as dead code. */ void *kasan_ptr_result; int kasan_int_result; static struct kunit_resource resource; static struct kunit_kasan_expectation fail_data; static bool multishot; /* * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the * first detected bug and panic the kernel if panic_on_warn is enabled. For * hardware tag-based KASAN also allow tag checking to be reenabled for each * test, see the comment for KUNIT_EXPECT_KASAN_FAIL(). */ static int kasan_test_init(struct kunit *test) { if (!kasan_enabled()) { kunit_err(test, "can't run KASAN tests with KASAN disabled"); return -1; } multishot = kasan_save_enable_multi_shot(); fail_data.report_found = false; kunit_add_named_resource(test, NULL, NULL, &resource, "kasan_data", &fail_data); return 0; } static void kasan_test_exit(struct kunit *test) { kasan_restore_multi_shot(multishot); KUNIT_EXPECT_FALSE(test, fail_data.report_found); } /** * KUNIT_EXPECT_KASAN_FAIL() - check that the executed expression produces a * KASAN report; causes a test failure otherwise. This relies on a KUnit * resource named "kasan_data". Do not use this name for KUnit resources * outside of KASAN tests. * * For hardware tag-based KASAN in sync mode, when a tag fault happens, tag * checking is auto-disabled. When this happens, this test handler reenables * tag checking. As tag checking can be only disabled or enabled per CPU, * this handler disables migration (preemption). * * Since the compiler doesn't see that the expression can change the fail_data * fields, it can reorder or optimize away the accesses to those fields. * Use READ/WRITE_ONCE() for the accesses and compiler barriers around the * expression to prevent that. * * In between KUNIT_EXPECT_KASAN_FAIL checks, fail_data.report_found is kept as * false. This allows detecting KASAN reports that happen outside of the checks * by asserting !fail_data.report_found at the start of KUNIT_EXPECT_KASAN_FAIL * and in kasan_test_exit. */ #define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \ kasan_sync_fault_possible()) \ migrate_disable(); \ KUNIT_EXPECT_FALSE(test, READ_ONCE(fail_data.report_found)); \ barrier(); \ expression; \ barrier(); \ if (!READ_ONCE(fail_data.report_found)) { \ KUNIT_FAIL(test, KUNIT_SUBTEST_INDENT "KASAN failure " \ "expected in \"" #expression \ "\", but none occurred"); \ } \ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \ if (READ_ONCE(fail_data.report_found)) \ kasan_enable_tagging_sync(); \ migrate_enable(); \ } \ WRITE_ONCE(fail_data.report_found, false); \ } while (0) #define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \ if (!IS_ENABLED(config)) \ kunit_skip((test), "Test requires " #config "=y"); \ } while (0) #define KASAN_TEST_NEEDS_CONFIG_OFF(test, config) do { \ if (IS_ENABLED(config)) \ kunit_skip((test), "Test requires " #config "=n"); \ } while (0) static void kmalloc_oob_right(struct kunit *test) { char *ptr; size_t size = 128 - KASAN_GRANULE_SIZE - 5; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); /* * An unaligned access past the requested kmalloc size. * Only generic KASAN can precisely detect these. */ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 'x'); /* * An aligned access into the first out-of-bounds granule that falls * within the aligned kmalloc object. */ KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + 5] = 'y'); /* Out-of-bounds access past the aligned kmalloc object. */ KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size + KASAN_GRANULE_SIZE + 5]); kfree(ptr); } static void kmalloc_oob_left(struct kunit *test) { char *ptr; size_t size = 15; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_KASAN_FAIL(test, *ptr = *(ptr - 1)); kfree(ptr); } static void kmalloc_node_oob_right(struct kunit *test) { char *ptr; size_t size = 4096; ptr = kmalloc_node(size, GFP_KERNEL, 0); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]); kfree(ptr); } /* * These kmalloc_pagealloc_* tests try allocating a memory chunk that doesn't * fit into a slab cache and therefore is allocated via the page allocator * fallback. Since this kind of fallback is only implemented for SLUB, these * tests are limited to that allocator. */ static void kmalloc_pagealloc_oob_right(struct kunit *test) { char *ptr; size_t size = KMALLOC_MAX_CACHE_SIZE + 10; KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0); kfree(ptr); } static void kmalloc_pagealloc_uaf(struct kunit *test) { char *ptr; size_t size = KMALLOC_MAX_CACHE_SIZE + 10; KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); } static void kmalloc_pagealloc_invalid_free(struct kunit *test) { char *ptr; size_t size = KMALLOC_MAX_CACHE_SIZE + 10; KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_KASAN_FAIL(test, kfree(ptr + 1)); } static void pagealloc_oob_right(struct kunit *test) { char *ptr; struct page *pages; size_t order = 4; size_t size = (1UL << (PAGE_SHIFT + order)); /* * With generic KASAN page allocations have no redzones, thus * out-of-bounds detection is not guaranteed. * See https://bugzilla.kernel.org/show_bug.cgi?id=210503. */ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); pages = alloc_pages(GFP_KERNEL, order); ptr = page_address(pages); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]); free_pages((unsigned long)ptr, order); } static void pagealloc_uaf(struct kunit *test) { char *ptr; struct page *pages; size_t order = 4; pages = alloc_pages(GFP_KERNEL, order); ptr = page_address(pages); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); free_pages((unsigned long)ptr, order); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); } static void kmalloc_large_oob_right(struct kunit *test) { char *ptr; size_t size = KMALLOC_MAX_CACHE_SIZE - 256; /* * Allocate a chunk that is large enough, but still fits into a slab * and does not trigger the page allocator fallback in SLUB. */ ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0); kfree(ptr); } static void krealloc_more_oob_helper(struct kunit *test, size_t size1, size_t size2) { char *ptr1, *ptr2; size_t middle; KUNIT_ASSERT_LT(test, size1, size2); middle = size1 + (size2 - size1) / 2; ptr1 = kmalloc(size1, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); ptr2 = krealloc(ptr1, size2, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); /* All offsets up to size2 must be accessible. */ ptr2[size1 - 1] = 'x'; ptr2[size1] = 'x'; ptr2[middle] = 'x'; ptr2[size2 - 1] = 'x'; /* Generic mode is precise, so unaligned size2 must be inaccessible. */ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x'); /* For all modes first aligned offset after size2 must be inaccessible. */ KUNIT_EXPECT_KASAN_FAIL(test, ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x'); kfree(ptr2); } static void krealloc_less_oob_helper(struct kunit *test, size_t size1, size_t size2) { char *ptr1, *ptr2; size_t middle; KUNIT_ASSERT_LT(test, size2, size1); middle = size2 + (size1 - size2) / 2; ptr1 = kmalloc(size1, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); ptr2 = krealloc(ptr1, size2, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); /* Must be accessible for all modes. */ ptr2[size2 - 1] = 'x'; /* Generic mode is precise, so unaligned size2 must be inaccessible. */ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x'); /* For all modes first aligned offset after size2 must be inaccessible. */ KUNIT_EXPECT_KASAN_FAIL(test, ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x'); /* * For all modes all size2, middle, and size1 should land in separate * granules and thus the latter two offsets should be inaccessible. */ KUNIT_EXPECT_LE(test, round_up(size2, KASAN_GRANULE_SIZE), round_down(middle, KASAN_GRANULE_SIZE)); KUNIT_EXPECT_LE(test, round_up(middle, KASAN_GRANULE_SIZE), round_down(size1, KASAN_GRANULE_SIZE)); KUNIT_EXPECT_KASAN_FAIL(test, ptr2[middle] = 'x'); KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1 - 1] = 'x'); KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1] = 'x'); kfree(ptr2); } static void krealloc_more_oob(struct kunit *test) { krealloc_more_oob_helper(test, 201, 235); } static void krealloc_less_oob(struct kunit *test) { krealloc_less_oob_helper(test, 235, 201); } static void krealloc_pagealloc_more_oob(struct kunit *test) { /* page_alloc fallback in only implemented for SLUB. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); krealloc_more_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 201, KMALLOC_MAX_CACHE_SIZE + 235); } static void krealloc_pagealloc_less_oob(struct kunit *test) { /* page_alloc fallback in only implemented for SLUB. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); krealloc_less_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 235, KMALLOC_MAX_CACHE_SIZE + 201); } /* * Check that krealloc() detects a use-after-free, returns NULL, * and doesn't unpoison the freed object. */ static void krealloc_uaf(struct kunit *test) { char *ptr1, *ptr2; int size1 = 201; int size2 = 235; ptr1 = kmalloc(size1, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); kfree(ptr1); KUNIT_EXPECT_KASAN_FAIL(test, ptr2 = krealloc(ptr1, size2, GFP_KERNEL)); KUNIT_ASSERT_PTR_EQ(test, (void *)ptr2, NULL); KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)ptr1); } static void kmalloc_oob_16(struct kunit *test) { struct { u64 words[2]; } *ptr1, *ptr2; /* This test is specifically crafted for the generic mode. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2); kfree(ptr1); kfree(ptr2); } static void kmalloc_uaf_16(struct kunit *test) { struct { u64 words[2]; } *ptr1, *ptr2; ptr1 = kmalloc(sizeof(*ptr1), GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); kfree(ptr2); KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2); kfree(ptr1); } /* * Note: in the memset tests below, the written range touches both valid and * invalid memory. This makes sure that the instrumentation does not only check * the starting address but the whole range. */ static void kmalloc_oob_memset_2(struct kunit *test) { char *ptr; size_t size = 128 - KASAN_GRANULE_SIZE; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, 2)); kfree(ptr); } static void kmalloc_oob_memset_4(struct kunit *test) { char *ptr; size_t size = 128 - KASAN_GRANULE_SIZE; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, 4)); kfree(ptr); } static void kmalloc_oob_memset_8(struct kunit *test) { char *ptr; size_t size = 128 - KASAN_GRANULE_SIZE; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, 8)); kfree(ptr); } static void kmalloc_oob_memset_16(struct kunit *test) { char *ptr; size_t size = 128 - KASAN_GRANULE_SIZE; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, 16)); kfree(ptr); } static void kmalloc_oob_in_memset(struct kunit *test) { char *ptr; size_t size = 128 - KASAN_GRANULE_SIZE; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); OPTIMIZER_HIDE_VAR(ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr, 0, size + KASAN_GRANULE_SIZE)); kfree(ptr); } static void kmalloc_memmove_negative_size(struct kunit *test) { char *ptr; size_t size = 64; size_t invalid_size = -2; /* * Hardware tag-based mode doesn't check memmove for negative size. * As a result, this test introduces a side-effect memory corruption, * which can result in a crash. */ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS); ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); memset((char *)ptr, 0, 64); OPTIMIZER_HIDE_VAR(ptr); OPTIMIZER_HIDE_VAR(invalid_size); KUNIT_EXPECT_KASAN_FAIL(test, memmove((char *)ptr, (char *)ptr + 4, invalid_size)); kfree(ptr); } static void kmalloc_memmove_invalid_size(struct kunit *test) { char *ptr; size_t size = 64; volatile size_t invalid_size = size; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); memset((char *)ptr, 0, 64); OPTIMIZER_HIDE_VAR(ptr); KUNIT_EXPECT_KASAN_FAIL(test, memmove((char *)ptr, (char *)ptr + 4, invalid_size)); kfree(ptr); } static void kmalloc_uaf(struct kunit *test) { char *ptr; size_t size = 10; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[8]); } static void kmalloc_uaf_memset(struct kunit *test) { char *ptr; size_t size = 33; /* * Only generic KASAN uses quarantine, which is required to avoid a * kernel memory corruption this test causes. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree(ptr); KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr, 0, size)); } static void kmalloc_uaf2(struct kunit *test) { char *ptr1, *ptr2; size_t size = 43; int counter = 0; again: ptr1 = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); kfree(ptr1); ptr2 = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); /* * For tag-based KASAN ptr1 and ptr2 tags might happen to be the same. * Allow up to 16 attempts at generating different tags. */ if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && ptr1 == ptr2 && counter++ < 16) { kfree(ptr2); goto again; } KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr1)[40]); KUNIT_EXPECT_PTR_NE(test, ptr1, ptr2); kfree(ptr2); } static void kfree_via_page(struct kunit *test) { char *ptr; size_t size = 8; struct page *page; unsigned long offset; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); page = virt_to_page(ptr); offset = offset_in_page(ptr); kfree(page_address(page) + offset); } static void kfree_via_phys(struct kunit *test) { char *ptr; size_t size = 8; phys_addr_t phys; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); phys = virt_to_phys(ptr); kfree(phys_to_virt(phys)); } static void kmem_cache_oob(struct kunit *test) { char *p; size_t size = 200; struct kmem_cache *cache; cache = kmem_cache_create("test_cache", size, 0, 0, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); p = kmem_cache_alloc(cache, GFP_KERNEL); if (!p) { kunit_err(test, "Allocation failed: %s\n", __func__); kmem_cache_destroy(cache); return; } KUNIT_EXPECT_KASAN_FAIL(test, *p = p[size + OOB_TAG_OFF]); kmem_cache_free(cache, p); kmem_cache_destroy(cache); } static void kmem_cache_accounted(struct kunit *test) { int i; char *p; size_t size = 200; struct kmem_cache *cache; cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); /* * Several allocations with a delay to allow for lazy per memcg kmem * cache creation. */ for (i = 0; i < 5; i++) { p = kmem_cache_alloc(cache, GFP_KERNEL); if (!p) goto free_cache; kmem_cache_free(cache, p); msleep(100); } free_cache: kmem_cache_destroy(cache); } static void kmem_cache_bulk(struct kunit *test) { struct kmem_cache *cache; size_t size = 200; char *p[10]; bool ret; int i; cache = kmem_cache_create("test_cache", size, 0, 0, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); ret = kmem_cache_alloc_bulk(cache, GFP_KERNEL, ARRAY_SIZE(p), (void **)&p); if (!ret) { kunit_err(test, "Allocation failed: %s\n", __func__); kmem_cache_destroy(cache); return; } for (i = 0; i < ARRAY_SIZE(p); i++) p[i][0] = p[i][size - 1] = 42; kmem_cache_free_bulk(cache, ARRAY_SIZE(p), (void **)&p); kmem_cache_destroy(cache); } static char global_array[10]; static void kasan_global_oob_right(struct kunit *test) { /* * Deliberate out-of-bounds access. To prevent CONFIG_UBSAN_LOCAL_BOUNDS * from failing here and panicking the kernel, access the array via a * volatile pointer, which will prevent the compiler from being able to * determine the array bounds. * * This access uses a volatile pointer to char (char *volatile) rather * than the more conventional pointer to volatile char (volatile char *) * because we want to prevent the compiler from making inferences about * the pointer itself (i.e. its array bounds), not the data that it * refers to. */ char *volatile array = global_array; char *p = &array[ARRAY_SIZE(global_array) + 3]; /* Only generic mode instruments globals. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); } static void kasan_global_oob_left(struct kunit *test) { char *volatile array = global_array; char *p = array - 3; /* * GCC is known to fail this test, skip it. * See https://bugzilla.kernel.org/show_bug.cgi?id=215051. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_CC_IS_CLANG); KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); } /* Check that ksize() makes the whole object accessible. */ static void ksize_unpoisons_memory(struct kunit *test) { char *ptr; size_t size = 123, real_size; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); real_size = ksize(ptr); /* This access shouldn't trigger a KASAN report. */ ptr[size] = 'x'; /* This one must. */ KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size]); kfree(ptr); } /* * Check that a use-after-free is detected by ksize() and via normal accesses * after it. */ static void ksize_uaf(struct kunit *test) { char *ptr; int size = 128 - KASAN_GRANULE_SIZE; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr)); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); } static void kasan_stack_oob(struct kunit *test) { char stack_array[10]; /* See comment in kasan_global_oob. */ char *volatile array = stack_array; char *p = &array[ARRAY_SIZE(stack_array) + OOB_TAG_OFF]; KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK); KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); } static void kasan_alloca_oob_left(struct kunit *test) { volatile int i = 10; char alloca_array[i]; /* See comment in kasan_global_oob. */ char *volatile array = alloca_array; char *p = array - 1; /* Only generic mode instruments dynamic allocas. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK); KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); } static void kasan_alloca_oob_right(struct kunit *test) { volatile int i = 10; char alloca_array[i]; /* See comment in kasan_global_oob. */ char *volatile array = alloca_array; char *p = array + i; /* Only generic mode instruments dynamic allocas. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK); KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); } static void kmem_cache_double_free(struct kunit *test) { char *p; size_t size = 200; struct kmem_cache *cache; cache = kmem_cache_create("test_cache", size, 0, 0, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); p = kmem_cache_alloc(cache, GFP_KERNEL); if (!p) { kunit_err(test, "Allocation failed: %s\n", __func__); kmem_cache_destroy(cache); return; } kmem_cache_free(cache, p); KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p)); kmem_cache_destroy(cache); } static void kmem_cache_invalid_free(struct kunit *test) { char *p; size_t size = 200; struct kmem_cache *cache; cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); p = kmem_cache_alloc(cache, GFP_KERNEL); if (!p) { kunit_err(test, "Allocation failed: %s\n", __func__); kmem_cache_destroy(cache); return; } /* Trigger invalid free, the object doesn't get freed. */ KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p + 1)); /* * Properly free the object to prevent the "Objects remaining in * test_cache on __kmem_cache_shutdown" BUG failure. */ kmem_cache_free(cache, p); kmem_cache_destroy(cache); } static void kmem_cache_double_destroy(struct kunit *test) { struct kmem_cache *cache; cache = kmem_cache_create("test_cache", 200, 0, 0, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); kmem_cache_destroy(cache); KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_destroy(cache)); } static void kasan_memchr(struct kunit *test) { char *ptr; size_t size = 24; /* * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. */ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT); if (OOB_TAG_OFF) size = round_up(size, OOB_TAG_OFF); ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); OPTIMIZER_HIDE_VAR(ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = memchr(ptr, '1', size + 1)); kfree(ptr); } static void kasan_memcmp(struct kunit *test) { char *ptr; size_t size = 24; int arr[9]; /* * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. */ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT); if (OOB_TAG_OFF) size = round_up(size, OOB_TAG_OFF); ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); memset(arr, 0, sizeof(arr)); OPTIMIZER_HIDE_VAR(ptr); OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = memcmp(ptr, arr, size+1)); kfree(ptr); } static void kasan_strings(struct kunit *test) { char *ptr; size_t size = 24; /* * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. */ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT); ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree(ptr); /* * Try to cause only 1 invalid access (less spam in dmesg). * For that we need ptr to point to zeroed byte. * Skip metadata that could be stored in freed object so ptr * will likely point to zeroed byte. */ ptr += 16; KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = strchr(ptr, '1')); KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = strrchr(ptr, '1')); KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strcmp(ptr, "2")); KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strncmp(ptr, "2", 1)); KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strlen(ptr)); KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strnlen(ptr, 1)); } static void kasan_bitops_modify(struct kunit *test, int nr, void *addr) { KUNIT_EXPECT_KASAN_FAIL(test, set_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, change_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(nr, addr)); } static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr) { KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, test_and_clear_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __test_and_clear_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr)); KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr)); #if defined(clear_bit_unlock_is_negative_byte) KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = clear_bit_unlock_is_negative_byte(nr, addr)); #endif } static void kasan_bitops_generic(struct kunit *test) { long *bits; /* This test is specifically crafted for the generic mode. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); /* * Allocate 1 more byte, which causes kzalloc to round up to 16 bytes; * this way we do not actually corrupt other memory. */ bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits); /* * Below calls try to access bit within allocated memory; however, the * below accesses are still out-of-bounds, since bitops are defined to * operate on the whole long the bit is in. */ kasan_bitops_modify(test, BITS_PER_LONG, bits); /* * Below calls try to access bit beyond allocated memory. */ kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits); kfree(bits); } static void kasan_bitops_tags(struct kunit *test) { long *bits; /* This test is specifically crafted for tag-based modes. */ KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); /* kmalloc-64 cache will be used and the last 16 bytes will be the redzone. */ bits = kzalloc(48, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits); /* Do the accesses past the 48 allocated bytes, but within the redone. */ kasan_bitops_modify(test, BITS_PER_LONG, (void *)bits + 48); kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, (void *)bits + 48); kfree(bits); } static void kmalloc_double_kzfree(struct kunit *test) { char *ptr; size_t size = 16; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree_sensitive(ptr); KUNIT_EXPECT_KASAN_FAIL(test, kfree_sensitive(ptr)); } static void vmalloc_oob(struct kunit *test) { void *area; KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC); /* * We have to be careful not to hit the guard page. * The MMU will catch that and crash us. */ area = vmalloc(3000); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, area); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)area)[3100]); vfree(area); } /* * Check that the assigned pointer tag falls within the [KASAN_TAG_MIN, * KASAN_TAG_KERNEL) range (note: excluding the match-all tag) for tag-based * modes. */ static void match_all_not_assigned(struct kunit *test) { char *ptr; struct page *pages; int i, size, order; KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); for (i = 0; i < 256; i++) { size = (get_random_int() % 1024) + 1; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); kfree(ptr); } for (i = 0; i < 256; i++) { order = (get_random_int() % 4) + 1; pages = alloc_pages(GFP_KERNEL, order); ptr = page_address(pages); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); free_pages((unsigned long)ptr, order); } } /* Check that 0xff works as a match-all pointer tag for tag-based modes. */ static void match_all_ptr_tag(struct kunit *test) { char *ptr; u8 tag; KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); ptr = kmalloc(128, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); /* Backup the assigned tag. */ tag = get_tag(ptr); KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL); /* Reset the tag to 0xff.*/ ptr = set_tag(ptr, KASAN_TAG_KERNEL); /* This access shouldn't trigger a KASAN report. */ *ptr = 0; /* Recover the pointer tag and free. */ ptr = set_tag(ptr, tag); kfree(ptr); } /* Check that there are no match-all memory tags for tag-based modes. */ static void match_all_mem_tag(struct kunit *test) { char *ptr; int tag; KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); ptr = kmalloc(128, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); /* For each possible tag value not matching the pointer tag. */ for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) { if (tag == get_tag(ptr)) continue; /* Mark the first memory granule with the chosen memory tag. */ kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag, false); /* This access must cause a KASAN report. */ KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0); } /* Recover the memory tag and free. */ kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr), false); kfree(ptr); } static struct kunit_case kasan_kunit_test_cases[] = { KUNIT_CASE(kmalloc_oob_right), KUNIT_CASE(kmalloc_oob_left), KUNIT_CASE(kmalloc_node_oob_right), KUNIT_CASE(kmalloc_pagealloc_oob_right), KUNIT_CASE(kmalloc_pagealloc_uaf), KUNIT_CASE(kmalloc_pagealloc_invalid_free), KUNIT_CASE(pagealloc_oob_right), KUNIT_CASE(pagealloc_uaf), KUNIT_CASE(kmalloc_large_oob_right), KUNIT_CASE(krealloc_more_oob), KUNIT_CASE(krealloc_less_oob), KUNIT_CASE(krealloc_pagealloc_more_oob), KUNIT_CASE(krealloc_pagealloc_less_oob), KUNIT_CASE(krealloc_uaf), KUNIT_CASE(kmalloc_oob_16), KUNIT_CASE(kmalloc_uaf_16), KUNIT_CASE(kmalloc_oob_in_memset), KUNIT_CASE(kmalloc_oob_memset_2), KUNIT_CASE(kmalloc_oob_memset_4), KUNIT_CASE(kmalloc_oob_memset_8), KUNIT_CASE(kmalloc_oob_memset_16), KUNIT_CASE(kmalloc_memmove_negative_size), KUNIT_CASE(kmalloc_memmove_invalid_size), KUNIT_CASE(kmalloc_uaf), KUNIT_CASE(kmalloc_uaf_memset), KUNIT_CASE(kmalloc_uaf2), KUNIT_CASE(kfree_via_page), KUNIT_CASE(kfree_via_phys), KUNIT_CASE(kmem_cache_oob), KUNIT_CASE(kmem_cache_accounted), KUNIT_CASE(kmem_cache_bulk), KUNIT_CASE(kasan_global_oob_right), KUNIT_CASE(kasan_global_oob_left), KUNIT_CASE(kasan_stack_oob), KUNIT_CASE(kasan_alloca_oob_left), KUNIT_CASE(kasan_alloca_oob_right), KUNIT_CASE(ksize_unpoisons_memory), KUNIT_CASE(ksize_uaf), KUNIT_CASE(kmem_cache_double_free), KUNIT_CASE(kmem_cache_invalid_free), KUNIT_CASE(kmem_cache_double_destroy), KUNIT_CASE(kasan_memchr), KUNIT_CASE(kasan_memcmp), KUNIT_CASE(kasan_strings), KUNIT_CASE(kasan_bitops_generic), KUNIT_CASE(kasan_bitops_tags), KUNIT_CASE(kmalloc_double_kzfree), KUNIT_CASE(vmalloc_oob), KUNIT_CASE(match_all_not_assigned), KUNIT_CASE(match_all_ptr_tag), KUNIT_CASE(match_all_mem_tag), {} }; static struct kunit_suite kasan_kunit_test_suite = { .name = "kasan", .init = kasan_test_init, .test_cases = kasan_kunit_test_cases, .exit = kasan_test_exit, }; kunit_test_suite(kasan_kunit_test_suite); MODULE_LICENSE("GPL");