From f8ff04e2be0815b34d11a72d08473a383a3c9eb5 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 30 Nov 2016 15:54:10 -0800 Subject: lib/debugobjects: export for use in modules Drivers, or other modules, that use a mixture of objects (especially objects embedded within other objects) would like to take advantage of the debugobjects facilities to help catch misuse. Currently, the debugobjects interface is only available to builtin drivers and requires a set of EXPORT_SYMBOL_GPL for use by modules. I am using the debugobjects in i915.ko to try and catch some invalid operations on embedded objects. The problem currently only presents itself across module unload so forcing i915 to be builtin is not an option. Link: http://lkml.kernel.org/r/20161122143039.6433-1-chris@chris-wilson.co.uk Signed-off-by: Chris Wilson Cc: "Du, Changbin" Cc: Thomas Gleixner Cc: Christian Borntraeger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/debugobjects.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'lib') diff --git a/lib/debugobjects.c b/lib/debugobjects.c index a8e12601eb37..056052dc8e91 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -362,6 +362,7 @@ void debug_object_init(void *addr, struct debug_obj_descr *descr) __debug_object_init(addr, descr, 0); } +EXPORT_SYMBOL_GPL(debug_object_init); /** * debug_object_init_on_stack - debug checks when an object on stack is @@ -376,6 +377,7 @@ void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr) __debug_object_init(addr, descr, 1); } +EXPORT_SYMBOL_GPL(debug_object_init_on_stack); /** * debug_object_activate - debug checks when an object is activated @@ -449,6 +451,7 @@ int debug_object_activate(void *addr, struct debug_obj_descr *descr) } return 0; } +EXPORT_SYMBOL_GPL(debug_object_activate); /** * debug_object_deactivate - debug checks when an object is deactivated @@ -496,6 +499,7 @@ void debug_object_deactivate(void *addr, struct debug_obj_descr *descr) raw_spin_unlock_irqrestore(&db->lock, flags); } +EXPORT_SYMBOL_GPL(debug_object_deactivate); /** * debug_object_destroy - debug checks when an object is destroyed @@ -542,6 +546,7 @@ void debug_object_destroy(void *addr, struct debug_obj_descr *descr) out_unlock: raw_spin_unlock_irqrestore(&db->lock, flags); } +EXPORT_SYMBOL_GPL(debug_object_destroy); /** * debug_object_free - debug checks when an object is freed @@ -582,6 +587,7 @@ void debug_object_free(void *addr, struct debug_obj_descr *descr) out_unlock: raw_spin_unlock_irqrestore(&db->lock, flags); } +EXPORT_SYMBOL_GPL(debug_object_free); /** * debug_object_assert_init - debug checks when object should be init-ed @@ -626,6 +632,7 @@ void debug_object_assert_init(void *addr, struct debug_obj_descr *descr) raw_spin_unlock_irqrestore(&db->lock, flags); } +EXPORT_SYMBOL_GPL(debug_object_assert_init); /** * debug_object_active_state - debug checks object usage state machine @@ -673,6 +680,7 @@ debug_object_active_state(void *addr, struct debug_obj_descr *descr, raw_spin_unlock_irqrestore(&db->lock, flags); } +EXPORT_SYMBOL_GPL(debug_object_active_state); #ifdef CONFIG_DEBUG_OBJECTS_FREE static void __debug_check_no_obj_freed(const void *address, unsigned long size) -- cgit v1.2.3 From 828347f8f9a558cf1af2faa46387a26564f2ac3e Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Wed, 30 Nov 2016 15:54:16 -0800 Subject: kasan: support use-after-scope detection Gcc revision 241896 implements use-after-scope detection. Will be available in gcc 7. Support it in KASAN. Gcc emits 2 new callbacks to poison/unpoison large stack objects when they go in/out of scope. Implement the callbacks and add a test. [dvyukov@google.com: v3] Link: http://lkml.kernel.org/r/1479998292-144502-1-git-send-email-dvyukov@google.com Link: http://lkml.kernel.org/r/1479226045-145148-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov Acked-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: [4.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test_kasan.c | 29 +++++++++++++++++++++++++++++ mm/kasan/kasan.c | 19 +++++++++++++++++++ mm/kasan/kasan.h | 1 + mm/kasan/report.c | 3 +++ 4 files changed, 52 insertions(+) (limited to 'lib') diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 5e51872b3fc1..fbdf87920093 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -20,6 +20,11 @@ #include #include +/* + * Note: test functions are marked noinline so that their names appear in + * reports. + */ + static noinline void __init kmalloc_oob_right(void) { char *ptr; @@ -411,6 +416,29 @@ static noinline void __init copy_user_test(void) kfree(kmem); } +static noinline void __init use_after_scope_test(void) +{ + volatile char *volatile p; + + pr_info("use-after-scope on int\n"); + { + int local = 0; + + p = (char *)&local; + } + p[0] = 1; + p[3] = 1; + + pr_info("use-after-scope on array\n"); + { + char local[1024] = {0}; + + p = local; + } + p[0] = 1; + p[1023] = 1; +} + static int __init kmalloc_tests_init(void) { kmalloc_oob_right(); @@ -436,6 +464,7 @@ static int __init kmalloc_tests_init(void) kasan_global_oob(); ksize_unpoisons_memory(); copy_user_test(); + use_after_scope_test(); return -EAGAIN; } diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 70c009741aab..0e9505f66ec1 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -764,6 +764,25 @@ EXPORT_SYMBOL(__asan_storeN_noabort); void __asan_handle_no_return(void) {} EXPORT_SYMBOL(__asan_handle_no_return); +/* Emitted by compiler to poison large objects when they go out of scope. */ +void __asan_poison_stack_memory(const void *addr, size_t size) +{ + /* + * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded + * by redzones, so we simply round up size to simplify logic. + */ + kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE), + KASAN_USE_AFTER_SCOPE); +} +EXPORT_SYMBOL(__asan_poison_stack_memory); + +/* Emitted by compiler to unpoison large objects when they go into scope. */ +void __asan_unpoison_stack_memory(const void *addr, size_t size) +{ + kasan_unpoison_shadow(addr, size); +} +EXPORT_SYMBOL(__asan_unpoison_stack_memory); + #ifdef CONFIG_MEMORY_HOTPLUG static int kasan_mem_notifier(struct notifier_block *nb, unsigned long action, void *data) diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 03f4545b103d..1c260e6b3b3c 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -21,6 +21,7 @@ #define KASAN_STACK_MID 0xF2 #define KASAN_STACK_RIGHT 0xF3 #define KASAN_STACK_PARTIAL 0xF4 +#define KASAN_USE_AFTER_SCOPE 0xF8 /* Don't break randconfig/all*config builds */ #ifndef KASAN_ABI_VERSION diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 24c1211fe9d5..073325aedc68 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -90,6 +90,9 @@ static void print_error_description(struct kasan_access_info *info) case KASAN_KMALLOC_FREE: bug_type = "use-after-free"; break; + case KASAN_USE_AFTER_SCOPE: + bug_type = "use-after-scope"; + break; } pr_err("BUG: KASAN: %s in %pS at addr %p\n", -- cgit v1.2.3