1 files changed, 160 insertions, 93 deletions

diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index b076f597a378..2b8e73f5f6a7 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -25,6 +25,8 @@
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
 #include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stackdepot.h>
 #include <linux/stacktrace.h>
 #include <linux/string.h>
 #include <linux/types.h>
@@ -35,44 +37,55 @@
 #include "../slab.h"
 
 /*
+ * Initialize Generic KASAN and enable runtime checks.
+ * This should be called from arch kasan_init() once shadow memory is ready.
+ */
+void __init kasan_init_generic(void)
+{
+	kasan_enable();
+
+	pr_info("KernelAddressSanitizer initialized (generic)\n");
+}
+
+/*
  * All functions below always inlined so compiler could
  * perform better optimizations in each of __asan_loadX/__assn_storeX
  * depending on memory access size X.
  */
 
-static __always_inline bool memory_is_poisoned_1(unsigned long addr)
+static __always_inline bool memory_is_poisoned_1(const void *addr)
 {
-	s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
+	s8 shadow_value = *(s8 *)kasan_mem_to_shadow(addr);
 
 	if (unlikely(shadow_value)) {
-		s8 last_accessible_byte = addr & KASAN_GRANULE_MASK;
+		s8 last_accessible_byte = (unsigned long)addr & KASAN_GRANULE_MASK;
 		return unlikely(last_accessible_byte >= shadow_value);
 	}
 
 	return false;
 }
 
-static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
+static __always_inline bool memory_is_poisoned_2_4_8(const void *addr,
 						unsigned long size)
 {
-	u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr);
+	u8 *shadow_addr = (u8 *)kasan_mem_to_shadow(addr);
 
 	/*
 	 * Access crosses 8(shadow size)-byte boundary. Such access maps
 	 * into 2 shadow bytes, so we need to check them both.
 	 */
-	if (unlikely(((addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))
+	if (unlikely((((unsigned long)addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))
 		return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
 
 	return memory_is_poisoned_1(addr + size - 1);
 }
 
-static __always_inline bool memory_is_poisoned_16(unsigned long addr)
+static __always_inline bool memory_is_poisoned_16(const void *addr)
 {
-	u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
+	u16 *shadow_addr = (u16 *)kasan_mem_to_shadow(addr);
 
 	/* Unaligned 16-bytes access maps into 3 shadow bytes. */
-	if (unlikely(!IS_ALIGNED(addr, KASAN_GRANULE_SIZE)))
+	if (unlikely(!IS_ALIGNED((unsigned long)addr, KASAN_GRANULE_SIZE)))
 		return *shadow_addr || memory_is_poisoned_1(addr + 15);
 
 	return *shadow_addr;
@@ -120,26 +133,26 @@ static __always_inline unsigned long memory_is_nonzero(const void *start,
 	return bytes_is_nonzero(start, (end - start) % 8);
 }
 
-static __always_inline bool memory_is_poisoned_n(unsigned long addr,
-						size_t size)
+static __always_inline bool memory_is_poisoned_n(const void *addr, size_t size)
 {
 	unsigned long ret;
 
-	ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr),
-			kasan_mem_to_shadow((void *)addr + size - 1) + 1);
+	ret = memory_is_nonzero(kasan_mem_to_shadow(addr),
+			kasan_mem_to_shadow(addr + size - 1) + 1);
 
 	if (unlikely(ret)) {
-		unsigned long last_byte = addr + size - 1;
-		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
+		const void *last_byte = addr + size - 1;
+		s8 *last_shadow = (s8 *)kasan_mem_to_shadow(last_byte);
+		s8 last_accessible_byte = (unsigned long)last_byte & KASAN_GRANULE_MASK;
 
 		if (unlikely(ret != (unsigned long)last_shadow ||
-			((long)(last_byte & KASAN_GRANULE_MASK) >= *last_shadow)))
+			     last_accessible_byte >= *last_shadow))
 			return true;
 	}
 	return false;
 }
 
-static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
+static __always_inline bool memory_is_poisoned(const void *addr, size_t size)
 {
 	if (__builtin_constant_p(size)) {
 		switch (size) {
@@ -159,11 +172,11 @@ static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
 	return memory_is_poisoned_n(addr, size);
 }
 
-static __always_inline bool check_region_inline(unsigned long addr,
+static __always_inline bool check_region_inline(const void *addr,
 						size_t size, bool write,
 						unsigned long ret_ip)
 {
-	if (!kasan_arch_is_ready())
+	if (!kasan_enabled())
 		return true;
 
 	if (unlikely(size == 0))
@@ -172,10 +185,8 @@ static __always_inline bool check_region_inline(unsigned long addr,
 	if (unlikely(addr + size < addr))
 		return !kasan_report(addr, size, write, ret_ip);
 
-	if (unlikely((void *)addr <
-		kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
+	if (unlikely(!addr_has_metadata(addr)))
 		return !kasan_report(addr, size, write, ret_ip);
-	}
 
 	if (likely(!memory_is_poisoned(addr, size)))
 		return true;
@@ -183,7 +194,7 @@ static __always_inline bool check_region_inline(unsigned long addr,
 	return !kasan_report(addr, size, write, ret_ip);
 }
 
-bool kasan_check_range(unsigned long addr, size_t size, bool write,
+bool kasan_check_range(const void *addr, size_t size, bool write,
 					unsigned long ret_ip)
 {
 	return check_region_inline(addr, size, write, ret_ip);
@@ -191,7 +202,12 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
 
 bool kasan_byte_accessible(const void *addr)
 {
-	s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
+	s8 shadow_byte;
+
+	if (!kasan_enabled())
+		return true;
+
+	shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
 
 	return shadow_byte >= 0 && shadow_byte < KASAN_GRANULE_SIZE;
 }
@@ -218,36 +234,37 @@ static void register_global(struct kasan_global *global)
 		     KASAN_GLOBAL_REDZONE, false);
 }
 
-void __asan_register_globals(struct kasan_global *globals, size_t size)
+void __asan_register_globals(void *ptr, ssize_t size)
 {
 	int i;
+	struct kasan_global *globals = ptr;
 
 	for (i = 0; i < size; i++)
 		register_global(&globals[i]);
 }
 EXPORT_SYMBOL(__asan_register_globals);
 
-void __asan_unregister_globals(struct kasan_global *globals, size_t size)
+void __asan_unregister_globals(void *ptr, ssize_t size)
 {
 }
 EXPORT_SYMBOL(__asan_unregister_globals);
 
 #define DEFINE_ASAN_LOAD_STORE(size)					\
-	void __asan_load##size(unsigned long addr)			\
+	void __asan_load##size(void *addr)				\
 	{								\
 		check_region_inline(addr, size, false, _RET_IP_);	\
 	}								\
 	EXPORT_SYMBOL(__asan_load##size);				\
 	__alias(__asan_load##size)					\
-	void __asan_load##size##_noabort(unsigned long);		\
+	void __asan_load##size##_noabort(void *);			\
 	EXPORT_SYMBOL(__asan_load##size##_noabort);			\
-	void __asan_store##size(unsigned long addr)			\
+	void __asan_store##size(void *addr)				\
 	{								\
 		check_region_inline(addr, size, true, _RET_IP_);	\
 	}								\
 	EXPORT_SYMBOL(__asan_store##size);				\
 	__alias(__asan_store##size)					\
-	void __asan_store##size##_noabort(unsigned long);		\
+	void __asan_store##size##_noabort(void *);			\
 	EXPORT_SYMBOL(__asan_store##size##_noabort)
 
 DEFINE_ASAN_LOAD_STORE(1);
@@ -256,24 +273,24 @@ DEFINE_ASAN_LOAD_STORE(4);
 DEFINE_ASAN_LOAD_STORE(8);
 DEFINE_ASAN_LOAD_STORE(16);
 
-void __asan_loadN(unsigned long addr, size_t size)
+void __asan_loadN(void *addr, ssize_t size)
 {
 	kasan_check_range(addr, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__asan_loadN);
 
 __alias(__asan_loadN)
-void __asan_loadN_noabort(unsigned long, size_t);
+void __asan_loadN_noabort(void *, ssize_t);
 EXPORT_SYMBOL(__asan_loadN_noabort);
 
-void __asan_storeN(unsigned long addr, size_t size)
+void __asan_storeN(void *addr, ssize_t size)
 {
 	kasan_check_range(addr, size, true, _RET_IP_);
 }
 EXPORT_SYMBOL(__asan_storeN);
 
 __alias(__asan_storeN)
-void __asan_storeN_noabort(unsigned long, size_t);
+void __asan_storeN_noabort(void *, ssize_t);
 EXPORT_SYMBOL(__asan_storeN_noabort);
 
 /* to shut up compiler complaints */
@@ -281,7 +298,7 @@ void __asan_handle_no_return(void) {}
 EXPORT_SYMBOL(__asan_handle_no_return);
 
 /* Emitted by compiler to poison alloca()ed objects. */
-void __asan_alloca_poison(unsigned long addr, size_t size)
+void __asan_alloca_poison(void *addr, ssize_t size)
 {
 	size_t rounded_up_size = round_up(size, KASAN_GRANULE_SIZE);
 	size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
@@ -292,7 +309,7 @@ void __asan_alloca_poison(unsigned long addr, size_t size)
 			KASAN_ALLOCA_REDZONE_SIZE);
 	const void *right_redzone = (const void *)(addr + rounded_up_size);
 
-	WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
+	WARN_ON(!IS_ALIGNED((unsigned long)addr, KASAN_ALLOCA_REDZONE_SIZE));
 
 	kasan_unpoison((const void *)(addr + rounded_down_size),
 			size - rounded_down_size, false);
@@ -304,18 +321,18 @@ void __asan_alloca_poison(unsigned long addr, size_t size)
 EXPORT_SYMBOL(__asan_alloca_poison);
 
 /* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
-void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
+void __asan_allocas_unpoison(void *stack_top, ssize_t stack_bottom)
 {
-	if (unlikely(!stack_top || stack_top > stack_bottom))
+	if (unlikely(!stack_top || stack_top > (void *)stack_bottom))
 		return;
 
-	kasan_unpoison(stack_top, stack_bottom - stack_top, false);
+	kasan_unpoison(stack_top, (void *)stack_bottom - stack_top, false);
 }
 EXPORT_SYMBOL(__asan_allocas_unpoison);
 
 /* Emitted by the compiler to [un]poison local variables. */
 #define DEFINE_ASAN_SET_SHADOW(byte) \
-	void __asan_set_shadow_##byte(const void *addr, size_t size)	\
+	void __asan_set_shadow_##byte(const void *addr, ssize_t size)	\
 	{								\
 		__memset((void *)addr, 0x##byte, size);			\
 	}								\
@@ -328,14 +345,6 @@ DEFINE_ASAN_SET_SHADOW(f3);
 DEFINE_ASAN_SET_SHADOW(f5);
 DEFINE_ASAN_SET_SHADOW(f8);
 
-/* Only allow cache merging when no per-object metadata is present. */
-slab_flags_t kasan_never_merge(void)
-{
-	if (!kasan_requires_meta())
-		return 0;
-	return SLAB_KASAN;
-}
-
 /*
  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
  * For larger allocations larger redzones are used.
@@ -357,66 +366,97 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
 {
 	unsigned int ok_size;
 	unsigned int optimal_size;
+	unsigned int rem_free_meta_size;
+	unsigned int orig_alloc_meta_offset;
 
 	if (!kasan_requires_meta())
 		return;
 
 	/*
-	 * SLAB_KASAN is used to mark caches that are sanitized by KASAN
-	 * and that thus have per-object metadata.
-	 * Currently this flag is used in two places:
-	 * 1. In slab_ksize() to account for per-object metadata when
-	 *    calculating the size of the accessible memory within the object.
-	 * 2. In slab_common.c via kasan_never_merge() to prevent merging of
-	 *    caches with per-object metadata.
+	 * SLAB_KASAN is used to mark caches that are sanitized by KASAN and
+	 * that thus have per-object metadata. Currently, this flag is used in
+	 * slab_ksize() to account for per-object metadata when calculating the
+	 * size of the accessible memory within the object. Additionally, we use
+	 * SLAB_NO_MERGE to prevent merging of caches with per-object metadata.
 	 */
-	*flags |= SLAB_KASAN;
+	*flags |= SLAB_KASAN | SLAB_NO_MERGE;
 
 	ok_size = *size;
 
-	/* Add alloc meta into redzone. */
+	/* Add alloc meta into the redzone. */
 	cache->kasan_info.alloc_meta_offset = *size;
 	*size += sizeof(struct kasan_alloc_meta);
 
-	/*
-	 * If alloc meta doesn't fit, don't add it.
-	 * This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal
-	 * to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for
-	 * larger sizes.
-	 */
+	/* If alloc meta doesn't fit, don't add it. */
 	if (*size > KMALLOC_MAX_SIZE) {
 		cache->kasan_info.alloc_meta_offset = 0;
 		*size = ok_size;
 		/* Continue, since free meta might still fit. */
 	}
 
+	ok_size = *size;
+	orig_alloc_meta_offset = cache->kasan_info.alloc_meta_offset;
+
 	/*
-	 * Add free meta into redzone when it's not possible to store
+	 * Store free meta in the redzone when it's not possible to store
 	 * it in the object. This is the case when:
 	 * 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can
 	 *    be touched after it was freed, or
 	 * 2. Object has a constructor, which means it's expected to
 	 *    retain its content until the next allocation, or
-	 * 3. Object is too small.
-	 * Otherwise cache->kasan_info.free_meta_offset = 0 is implied.
+	 * 3. It is from a kmalloc cache which enables the debug option
+	 *    to store original size.
 	 */
 	if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor ||
-	    cache->object_size < sizeof(struct kasan_free_meta)) {
-		ok_size = *size;
-
+	     slub_debug_orig_size(cache)) {
 		cache->kasan_info.free_meta_offset = *size;
 		*size += sizeof(struct kasan_free_meta);
+		goto free_meta_added;
+	}
 
-		/* If free meta doesn't fit, don't add it. */
-		if (*size > KMALLOC_MAX_SIZE) {
-			cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
-			*size = ok_size;
-		}
+	/*
+	 * Otherwise, if the object is large enough to contain free meta,
+	 * store it within the object.
+	 */
+	if (sizeof(struct kasan_free_meta) <= cache->object_size) {
+		/* cache->kasan_info.free_meta_offset = 0 is implied. */
+		goto free_meta_added;
+	}
+
+	/*
+	 * For smaller objects, store the beginning of free meta within the
+	 * object and the end in the redzone. And thus shift the location of
+	 * alloc meta to free up space for free meta.
+	 * This is only possible when slub_debug is disabled, as otherwise
+	 * the end of free meta will overlap with slub_debug metadata.
+	 */
+	if (!__slub_debug_enabled()) {
+		rem_free_meta_size = sizeof(struct kasan_free_meta) -
+							cache->object_size;
+		*size += rem_free_meta_size;
+		if (cache->kasan_info.alloc_meta_offset != 0)
+			cache->kasan_info.alloc_meta_offset += rem_free_meta_size;
+		goto free_meta_added;
+	}
+
+	/*
+	 * If the object is small and slub_debug is enabled, store free meta
+	 * in the redzone after alloc meta.
+	 */
+	cache->kasan_info.free_meta_offset = *size;
+	*size += sizeof(struct kasan_free_meta);
+
+free_meta_added:
+	/* If free meta doesn't fit, don't add it. */
+	if (*size > KMALLOC_MAX_SIZE) {
+		cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
+		cache->kasan_info.alloc_meta_offset = orig_alloc_meta_offset;
+		*size = ok_size;
 	}
 
 	/* Calculate size with optimal redzone. */
 	optimal_size = cache->object_size + optimal_redzone(cache->object_size);
-	/* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */
+	/* Limit it with KMALLOC_MAX_SIZE. */
 	if (optimal_size > KMALLOC_MAX_SIZE)
 		optimal_size = KMALLOC_MAX_SIZE;
 	/* Use optimal size if the size with added metas is not large enough. */
@@ -446,8 +486,32 @@ void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
 	struct kasan_alloc_meta *alloc_meta;
 
 	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (alloc_meta)
+	if (alloc_meta) {
+		/* Zero out alloc meta to mark it as invalid. */
 		__memset(alloc_meta, 0, sizeof(*alloc_meta));
+	}
+
+	/*
+	 * Explicitly marking free meta as invalid is not required: the shadow
+	 * value for the first 8 bytes of a newly allocated object is not
+	 * KASAN_SLAB_FREE_META.
+	 */
+}
+
+static void release_alloc_meta(struct kasan_alloc_meta *meta)
+{
+	/* Zero out alloc meta to mark it as invalid. */
+	__memset(meta, 0, sizeof(*meta));
+}
+
+static void release_free_meta(const void *object, struct kasan_free_meta *meta)
+{
+	/* Check if free meta is valid. */
+	if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_SLAB_FREE_META)
+		return;
+
+	/* Mark free meta as invalid. */
+	*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
 }
 
 size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object)
@@ -468,7 +532,11 @@ size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object)
 			sizeof(struct kasan_free_meta) : 0);
 }
 
-static void __kasan_record_aux_stack(void *addr, bool can_alloc)
+/*
+ * This function avoids dynamic memory allocations and thus can be called from
+ * contexts that do not allow allocating memory.
+ */
+void kasan_record_aux_stack(void *addr)
 {
 	struct slab *slab = kasan_addr_to_slab(addr);
 	struct kmem_cache *cache;
@@ -485,17 +553,7 @@ static void __kasan_record_aux_stack(void *addr, bool can_alloc)
 		return;
 
 	alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
-	alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT, can_alloc);
-}
-
-void kasan_record_aux_stack(void *addr)
-{
-	return __kasan_record_aux_stack(addr, true);
-}
-
-void kasan_record_aux_stack_noalloc(void *addr)
-{
-	return __kasan_record_aux_stack(addr, false);
+	alloc_meta->aux_stack[0] = kasan_save_stack(0, 0);
 }
 
 void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
@@ -503,8 +561,13 @@ void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
 	struct kasan_alloc_meta *alloc_meta;
 
 	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (alloc_meta)
-		kasan_set_track(&alloc_meta->alloc_track, flags);
+	if (!alloc_meta)
+		return;
+
+	/* Invalidate previous stack traces (might exist for krealloc or mempool). */
+	release_alloc_meta(alloc_meta);
+
+	kasan_save_track(&alloc_meta->alloc_track, flags);
 }
 
 void kasan_save_free_info(struct kmem_cache *cache, void *object)
@@ -515,7 +578,11 @@ void kasan_save_free_info(struct kmem_cache *cache, void *object)
 	if (!free_meta)
 		return;
 
-	kasan_set_track(&free_meta->free_track, GFP_NOWAIT);
-	/* The object was freed and has free track set. */
-	*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREETRACK;
+	/* Invalidate previous stack trace (might exist for mempool). */
+	release_free_meta(object, free_meta);
+
+	kasan_save_track(&free_meta->free_track, 0);
+
+	/* Mark free meta as valid. */
+	*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE_META;
 }