diff options
Diffstat (limited to 'mm/kasan')
| -rw-r--r-- | mm/kasan/kasan_test_c.c | 26 | ||||
| -rw-r--r-- | mm/kasan/report.c | 34 |
2 files changed, 55 insertions, 5 deletions
diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c index 59d673400085..5f922dd38ffa 100644 --- a/mm/kasan/kasan_test_c.c +++ b/mm/kasan/kasan_test_c.c @@ -1073,14 +1073,11 @@ static void kmem_cache_rcu_uaf(struct kunit *test) kmem_cache_destroy(cache); } -static void empty_cache_ctor(void *object) { } - static void kmem_cache_double_destroy(struct kunit *test) { struct kmem_cache *cache; - /* Provide a constructor to prevent cache merging. */ - cache = kmem_cache_create("test_cache", 200, 0, 0, empty_cache_ctor); + cache = kmem_cache_create("test_cache", 200, 0, SLAB_NO_MERGE, NULL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); kmem_cache_destroy(cache); KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_destroy(cache)); @@ -1570,6 +1567,7 @@ static void kasan_memcmp(struct kunit *test) static void kasan_strings(struct kunit *test) { char *ptr; + char *src; size_t size = 24; /* @@ -1581,6 +1579,25 @@ static void kasan_strings(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + src = kmalloc(KASAN_GRANULE_SIZE, GFP_KERNEL | __GFP_ZERO); + strscpy(src, "f0cacc1a0000000", KASAN_GRANULE_SIZE); + + /* + * Make sure that strscpy() does not trigger KASAN if it overreads into + * poisoned memory. + * + * The expected size does not include the terminator '\0' + * so it is (KASAN_GRANULE_SIZE - 2) == + * KASAN_GRANULE_SIZE - ("initial removed character" + "\0"). + */ + KUNIT_EXPECT_EQ(test, KASAN_GRANULE_SIZE - 2, + strscpy(ptr, src + 1, KASAN_GRANULE_SIZE)); + + /* strscpy should fail if the first byte is unreadable. */ + KUNIT_EXPECT_KASAN_FAIL(test, strscpy(ptr, src + KASAN_GRANULE_SIZE, + KASAN_GRANULE_SIZE)); + + kfree(src); kfree(ptr); /* @@ -2130,4 +2147,5 @@ static struct kunit_suite kasan_kunit_test_suite = { kunit_test_suite(kasan_kunit_test_suite); +MODULE_DESCRIPTION("KUnit tests for checking KASAN bug-detection capabilities"); MODULE_LICENSE("GPL"); diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 3fe77a360f1c..8357e1a33699 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -370,6 +370,36 @@ static inline bool init_task_stack_addr(const void *addr) sizeof(init_thread_union.stack)); } +/* + * This function is invoked with report_lock (a raw_spinlock) held. A + * PREEMPT_RT kernel cannot call find_vm_area() as it will acquire a sleeping + * rt_spinlock. + * + * For !RT kernel, the PROVE_RAW_LOCK_NESTING config option will print a + * lockdep warning for this raw_spinlock -> spinlock dependency. This config + * option is enabled by default to ensure better test coverage to expose this + * kind of RT kernel problem. This lockdep splat, however, can be suppressed + * by using DEFINE_WAIT_OVERRIDE_MAP() if it serves a useful purpose and the + * invalid PREEMPT_RT case has been taken care of. + */ +static inline struct vm_struct *kasan_find_vm_area(void *addr) +{ + static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP); + struct vm_struct *va; + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + return NULL; + + /* + * Suppress lockdep warning and fetch vmalloc area of the + * offending address. + */ + lock_map_acquire_try(&vmalloc_map); + va = find_vm_area(addr); + lock_map_release(&vmalloc_map); + return va; +} + static void print_address_description(void *addr, u8 tag, struct kasan_report_info *info) { @@ -399,7 +429,7 @@ static void print_address_description(void *addr, u8 tag, } if (is_vmalloc_addr(addr)) { - struct vm_struct *va = find_vm_area(addr); + struct vm_struct *va = kasan_find_vm_area(addr); if (va) { pr_err("The buggy address belongs to the virtual mapping at\n" @@ -409,6 +439,8 @@ static void print_address_description(void *addr, u8 tag, pr_err("\n"); page = vmalloc_to_page(addr); + } else { + pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr); } } |