1 files changed, 353 insertions, 494 deletions

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 73c9cbfdedf4..1d27f1bd260b 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -1,25 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains common generic and tag-based KASAN code.
+ * This file contains common KASAN code.
  *
  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <andreyknvl@gmail.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #include <linux/export.h>
-#include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/kasan.h>
 #include <linux/kernel.h>
-#include <linux/kmemleak.h>
 #include <linux/linkage.h>
 #include <linux/memblock.h>
 #include <linux/memory.h>
@@ -27,168 +20,94 @@
 #include <linux/module.h>
 #include <linux/printk.h>
 #include <linux/sched.h>
+#include <linux/sched/clock.h>
 #include <linux/sched/task_stack.h>
 #include <linux/slab.h>
+#include <linux/stackdepot.h>
 #include <linux/stacktrace.h>
 #include <linux/string.h>
 #include <linux/types.h>
-#include <linux/vmalloc.h>
 #include <linux/bug.h>
 
 #include "kasan.h"
 #include "../slab.h"
 
-static inline int in_irqentry_text(unsigned long ptr)
+#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS)
+/*
+ * Definition of the unified static key declared in kasan-enabled.h.
+ * This provides consistent runtime enable/disable across KASAN modes.
+ */
+DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
+EXPORT_SYMBOL_GPL(kasan_flag_enabled);
+#endif
+
+struct slab *kasan_addr_to_slab(const void *addr)
 {
-	return (ptr >= (unsigned long)&__irqentry_text_start &&
-		ptr < (unsigned long)&__irqentry_text_end) ||
-		(ptr >= (unsigned long)&__softirqentry_text_start &&
-		 ptr < (unsigned long)&__softirqentry_text_end);
+	if (virt_addr_valid(addr))
+		return virt_to_slab(addr);
+	return NULL;
 }
 
-static inline void filter_irq_stacks(struct stack_trace *trace)
+depot_stack_handle_t kasan_save_stack(gfp_t flags, depot_flags_t depot_flags)
 {
-	int i;
+	unsigned long entries[KASAN_STACK_DEPTH];
+	unsigned int nr_entries;
 
-	if (!trace->nr_entries)
-		return;
-	for (i = 0; i < trace->nr_entries; i++)
-		if (in_irqentry_text(trace->entries[i])) {
-			/* Include the irqentry function into the stack. */
-			trace->nr_entries = i + 1;
-			break;
-		}
+	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
+	return stack_depot_save_flags(entries, nr_entries, flags, depot_flags);
 }
 
-static inline depot_stack_handle_t save_stack(gfp_t flags)
+void kasan_set_track(struct kasan_track *track, depot_stack_handle_t stack)
 {
-	unsigned long entries[KASAN_STACK_DEPTH];
-	struct stack_trace trace = {
-		.nr_entries = 0,
-		.entries = entries,
-		.max_entries = KASAN_STACK_DEPTH,
-		.skip = 0
-	};
+#ifdef CONFIG_KASAN_EXTRA_INFO
+	u32 cpu = raw_smp_processor_id();
+	u64 ts_nsec = local_clock();
 
-	save_stack_trace(&trace);
-	filter_irq_stacks(&trace);
-	if (trace.nr_entries != 0 &&
-	    trace.entries[trace.nr_entries-1] == ULONG_MAX)
-		trace.nr_entries--;
-
-	return depot_save_stack(&trace, flags);
+	track->cpu = cpu;
+	track->timestamp = ts_nsec >> 9;
+#endif /* CONFIG_KASAN_EXTRA_INFO */
+	track->pid = current->pid;
+	track->stack = stack;
 }
 
-static inline void set_track(struct kasan_track *track, gfp_t flags)
+void kasan_save_track(struct kasan_track *track, gfp_t flags)
 {
-	track->pid = current->pid;
-	track->stack = save_stack(flags);
+	depot_stack_handle_t stack;
+
+	stack = kasan_save_stack(flags, STACK_DEPOT_FLAG_CAN_ALLOC);
+	kasan_set_track(track, stack);
 }
 
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 void kasan_enable_current(void)
 {
 	current->kasan_depth++;
 }
+EXPORT_SYMBOL(kasan_enable_current);
 
 void kasan_disable_current(void)
 {
 	current->kasan_depth--;
 }
+EXPORT_SYMBOL(kasan_disable_current);
 
-void kasan_check_read(const volatile void *p, unsigned int size)
-{
-	check_memory_region((unsigned long)p, size, false, _RET_IP_);
-}
-EXPORT_SYMBOL(kasan_check_read);
-
-void kasan_check_write(const volatile void *p, unsigned int size)
-{
-	check_memory_region((unsigned long)p, size, true, _RET_IP_);
-}
-EXPORT_SYMBOL(kasan_check_write);
-
-#undef memset
-void *memset(void *addr, int c, size_t len)
-{
-	check_memory_region((unsigned long)addr, len, true, _RET_IP_);
-
-	return __memset(addr, c, len);
-}
-
-#undef memmove
-void *memmove(void *dest, const void *src, size_t len)
-{
-	check_memory_region((unsigned long)src, len, false, _RET_IP_);
-	check_memory_region((unsigned long)dest, len, true, _RET_IP_);
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
-	return __memmove(dest, src, len);
-}
-
-#undef memcpy
-void *memcpy(void *dest, const void *src, size_t len)
+void __kasan_unpoison_range(const void *address, size_t size)
 {
-	check_memory_region((unsigned long)src, len, false, _RET_IP_);
-	check_memory_region((unsigned long)dest, len, true, _RET_IP_);
-
-	return __memcpy(dest, src, len);
-}
-
-/*
- * Poisons the shadow memory for 'size' bytes starting from 'addr'.
- * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
- */
-void kasan_poison_shadow(const void *address, size_t size, u8 value)
-{
-	void *shadow_start, *shadow_end;
-
-	/*
-	 * Perform shadow offset calculation based on untagged address, as
-	 * some of the callers (e.g. kasan_poison_object_data) pass tagged
-	 * addresses to this function.
-	 */
-	address = reset_tag(address);
-
-	shadow_start = kasan_mem_to_shadow(address);
-	shadow_end = kasan_mem_to_shadow(address + size);
-
-	__memset(shadow_start, value, shadow_end - shadow_start);
-}
-
-void kasan_unpoison_shadow(const void *address, size_t size)
-{
-	u8 tag = get_tag(address);
-
-	/*
-	 * Perform shadow offset calculation based on untagged address, as
-	 * some of the callers (e.g. kasan_unpoison_object_data) pass tagged
-	 * addresses to this function.
-	 */
-	address = reset_tag(address);
-
-	kasan_poison_shadow(address, size, tag);
-
-	if (size & KASAN_SHADOW_MASK) {
-		u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
-
-		if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-			*shadow = tag;
-		else
-			*shadow = size & KASAN_SHADOW_MASK;
-	}
-}
-
-static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
-{
-	void *base = task_stack_page(task);
-	size_t size = sp - base;
+	if (is_kfence_address(address))
+		return;
 
-	kasan_unpoison_shadow(base, size);
+	kasan_unpoison(address, size, false);
 }
 
+#ifdef CONFIG_KASAN_STACK
 /* Unpoison the entire stack for a task. */
 void kasan_unpoison_task_stack(struct task_struct *task)
 {
-	__kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
+	void *base = task_stack_page(task);
+
+	kasan_unpoison(base, THREAD_SIZE, false);
 }
 
 /* Unpoison the stack for the current task beyond a watermark sp value. */
@@ -201,149 +120,57 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
 	 */
 	void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
 
-	kasan_unpoison_shadow(base, watermark - base);
+	kasan_unpoison(base, watermark - base, false);
 }
+#endif /* CONFIG_KASAN_STACK */
 
-/*
- * Clear all poison for the region between the current SP and a provided
- * watermark value, as is sometimes required prior to hand-crafted asm function
- * returns in the middle of functions.
- */
-void kasan_unpoison_stack_above_sp_to(const void *watermark)
-{
-	const void *sp = __builtin_frame_address(0);
-	size_t size = watermark - sp;
-
-	if (WARN_ON(sp > watermark))
-		return;
-	kasan_unpoison_shadow(sp, size);
-}
-
-void kasan_alloc_pages(struct page *page, unsigned int order)
+bool __kasan_unpoison_pages(struct page *page, unsigned int order, bool init)
 {
 	u8 tag;
 	unsigned long i;
 
 	if (unlikely(PageHighMem(page)))
-		return;
+		return false;
+
+	if (!kasan_sample_page_alloc(order))
+		return false;
 
-	tag = random_tag();
+	tag = kasan_random_tag();
+	kasan_unpoison(set_tag(page_address(page), tag),
+		       PAGE_SIZE << order, init);
 	for (i = 0; i < (1 << order); i++)
 		page_kasan_tag_set(page + i, tag);
-	kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
-}
-
-void kasan_free_pages(struct page *page, unsigned int order)
-{
-	if (likely(!PageHighMem(page)))
-		kasan_poison_shadow(page_address(page),
-				PAGE_SIZE << order,
-				KASAN_FREE_PAGE);
-}
-
-/*
- * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
- * For larger allocations larger redzones are used.
- */
-static inline unsigned int optimal_redzone(unsigned int object_size)
-{
-	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-		return 0;
-
-	return
-		object_size <= 64        - 16   ? 16 :
-		object_size <= 128       - 32   ? 32 :
-		object_size <= 512       - 64   ? 64 :
-		object_size <= 4096      - 128  ? 128 :
-		object_size <= (1 << 14) - 256  ? 256 :
-		object_size <= (1 << 15) - 512  ? 512 :
-		object_size <= (1 << 16) - 1024 ? 1024 : 2048;
-}
-
-void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
-			slab_flags_t *flags)
-{
-	unsigned int orig_size = *size;
-	unsigned int redzone_size;
-	int redzone_adjust;
-
-	/* Add alloc meta. */
-	cache->kasan_info.alloc_meta_offset = *size;
-	*size += sizeof(struct kasan_alloc_meta);
-
-	/* Add free meta. */
-	if (IS_ENABLED(CONFIG_KASAN_GENERIC) &&
-	    (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor ||
-	     cache->object_size < sizeof(struct kasan_free_meta))) {
-		cache->kasan_info.free_meta_offset = *size;
-		*size += sizeof(struct kasan_free_meta);
-	}
-
-	redzone_size = optimal_redzone(cache->object_size);
-	redzone_adjust = redzone_size -	(*size - cache->object_size);
-	if (redzone_adjust > 0)
-		*size += redzone_adjust;
-
-	*size = min_t(unsigned int, KMALLOC_MAX_SIZE,
-			max(*size, cache->object_size + redzone_size));
-
-	/*
-	 * If the metadata doesn't fit, don't enable KASAN at all.
-	 */
-	if (*size <= cache->kasan_info.alloc_meta_offset ||
-			*size <= cache->kasan_info.free_meta_offset) {
-		cache->kasan_info.alloc_meta_offset = 0;
-		cache->kasan_info.free_meta_offset = 0;
-		*size = orig_size;
-		return;
-	}
-
-	*flags |= SLAB_KASAN;
-}
 
-size_t kasan_metadata_size(struct kmem_cache *cache)
-{
-	return (cache->kasan_info.alloc_meta_offset ?
-		sizeof(struct kasan_alloc_meta) : 0) +
-		(cache->kasan_info.free_meta_offset ?
-		sizeof(struct kasan_free_meta) : 0);
+	return true;
 }
 
-struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
-					const void *object)
+void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
 {
-	BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
-	return (void *)object + cache->kasan_info.alloc_meta_offset;
-}
-
-struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
-				      const void *object)
-{
-	BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
-	return (void *)object + cache->kasan_info.free_meta_offset;
+	if (likely(!PageHighMem(page)))
+		kasan_poison(page_address(page), PAGE_SIZE << order,
+			     KASAN_PAGE_FREE, init);
 }
 
-void kasan_poison_slab(struct page *page)
+void __kasan_poison_slab(struct slab *slab)
 {
+	struct page *page = slab_page(slab);
 	unsigned long i;
 
-	for (i = 0; i < (1 << compound_order(page)); i++)
+	for (i = 0; i < compound_nr(page); i++)
 		page_kasan_tag_reset(page + i);
-	kasan_poison_shadow(page_address(page),
-			PAGE_SIZE << compound_order(page),
-			KASAN_KMALLOC_REDZONE);
+	kasan_poison(page_address(page), page_size(page),
+		     KASAN_SLAB_REDZONE, false);
 }
 
-void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
+void __kasan_unpoison_new_object(struct kmem_cache *cache, void *object)
 {
-	kasan_unpoison_shadow(object, cache->object_size);
+	kasan_unpoison(object, cache->object_size, false);
 }
 
-void kasan_poison_object_data(struct kmem_cache *cache, void *object)
+void __kasan_poison_new_object(struct kmem_cache *cache, void *object)
 {
-	kasan_poison_shadow(object,
-			round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
-			KASAN_KMALLOC_REDZONE);
+	kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE),
+			KASAN_SLAB_REDZONE, false);
 }
 
 /*
@@ -355,364 +182,396 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object)
  * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
  *    accessed after being freed. We preassign tags for objects in these
  *    caches as well.
- * 3. For SLAB allocator we can't preassign tags randomly since the freelist
- *    is stored as an array of indexes instead of a linked list. Assign tags
- *    based on objects indexes, so that objects that are next to each other
- *    get different tags.
  */
-static u8 assign_tag(struct kmem_cache *cache, const void *object,
-			bool init, bool krealloc)
+static inline u8 assign_tag(struct kmem_cache *cache,
+					const void *object, bool init)
 {
-	/* Reuse the same tag for krealloc'ed objects. */
-	if (krealloc)
-		return get_tag(object);
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+		return 0xff;
 
 	/*
 	 * If the cache neither has a constructor nor has SLAB_TYPESAFE_BY_RCU
 	 * set, assign a tag when the object is being allocated (init == false).
 	 */
 	if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
-		return init ? KASAN_TAG_KERNEL : random_tag();
+		return init ? KASAN_TAG_KERNEL : kasan_random_tag();
 
-	/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
-#ifdef CONFIG_SLAB
-	/* For SLAB assign tags based on the object index in the freelist. */
-	return (u8)obj_to_index(cache, virt_to_page(object), (void *)object);
-#else
 	/*
-	 * For SLUB assign a random tag during slab creation, otherwise reuse
+	 * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
+	 * assign a random tag during slab creation, otherwise reuse
 	 * the already assigned tag.
 	 */
-	return init ? random_tag() : get_tag(object);
-#endif
+	return init ? kasan_random_tag() : get_tag(object);
 }
 
-void * __must_check kasan_init_slab_obj(struct kmem_cache *cache,
+void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
 						const void *object)
 {
-	struct kasan_alloc_meta *alloc_info;
+	/* Initialize per-object metadata if it is present. */
+	if (kasan_requires_meta())
+		kasan_init_object_meta(cache, object);
 
-	if (!(cache->flags & SLAB_KASAN))
-		return (void *)object;
+	/* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */
+	object = set_tag(object, assign_tag(cache, object, true));
 
-	alloc_info = get_alloc_info(cache, object);
-	__memset(alloc_info, 0, sizeof(*alloc_info));
+	return (void *)object;
+}
 
-	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-		object = set_tag(object,
-				assign_tag(cache, object, true, false));
+/* Returns true when freeing the object is not safe. */
+static bool check_slab_allocation(struct kmem_cache *cache, void *object,
+				  unsigned long ip)
+{
+	void *tagged_object = object;
 
-	return (void *)object;
+	object = kasan_reset_tag(object);
+
+	if (unlikely(nearest_obj(cache, virt_to_slab(object), object) != object)) {
+		kasan_report_invalid_free(tagged_object, ip, KASAN_REPORT_INVALID_FREE);
+		return true;
+	}
+
+	if (!kasan_byte_accessible(tagged_object)) {
+		kasan_report_invalid_free(tagged_object, ip, KASAN_REPORT_DOUBLE_FREE);
+		return true;
+	}
+
+	return false;
 }
 
-void * __must_check kasan_slab_alloc(struct kmem_cache *cache, void *object,
-					gfp_t flags)
+static inline void poison_slab_object(struct kmem_cache *cache, void *object,
+				      bool init)
 {
-	return kasan_kmalloc(cache, object, cache->object_size, flags);
+	void *tagged_object = object;
+
+	object = kasan_reset_tag(object);
+
+	kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE),
+			KASAN_SLAB_FREE, init);
+
+	if (kasan_stack_collection_enabled())
+		kasan_save_free_info(cache, tagged_object);
 }
 
-static inline bool shadow_invalid(u8 tag, s8 shadow_byte)
+bool __kasan_slab_pre_free(struct kmem_cache *cache, void *object,
+				unsigned long ip)
 {
-	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
-		return shadow_byte < 0 ||
-			shadow_byte >= KASAN_SHADOW_SCALE_SIZE;
-	else
-		return tag != (u8)shadow_byte;
+	if (is_kfence_address(object))
+		return false;
+	return check_slab_allocation(cache, object, ip);
 }
 
-static bool __kasan_slab_free(struct kmem_cache *cache, void *object,
-			      unsigned long ip, bool quarantine)
+bool __kasan_slab_free(struct kmem_cache *cache, void *object, bool init,
+		       bool still_accessible, bool no_quarantine)
 {
-	s8 shadow_byte;
-	u8 tag;
-	void *tagged_object;
-	unsigned long rounded_up_size;
+	if (is_kfence_address(object))
+		return false;
 
-	tag = get_tag(object);
-	tagged_object = object;
-	object = reset_tag(object);
+	/*
+	 * If this point is reached with an object that must still be
+	 * accessible under RCU, we can't poison it; in that case, also skip the
+	 * quarantine. This should mostly only happen when CONFIG_SLUB_RCU_DEBUG
+	 * has been disabled manually.
+	 *
+	 * Putting the object on the quarantine wouldn't help catch UAFs (since
+	 * we can't poison it here), and it would mask bugs caused by
+	 * SLAB_TYPESAFE_BY_RCU users not being careful enough about object
+	 * reuse; so overall, putting the object into the quarantine here would
+	 * be counterproductive.
+	 */
+	if (still_accessible)
+		return false;
 
-	if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
-	    object)) {
-		kasan_report_invalid_free(tagged_object, ip);
-		return true;
-	}
+	poison_slab_object(cache, object, init);
 
-	/* RCU slabs could be legally used after free within the RCU period */
-	if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
+	if (no_quarantine)
 		return false;
 
-	shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
-	if (shadow_invalid(tag, shadow_byte)) {
-		kasan_report_invalid_free(tagged_object, ip);
+	/*
+	 * If the object is put into quarantine, do not let slab put the object
+	 * onto the freelist for now. The object's metadata is kept until the
+	 * object gets evicted from quarantine.
+	 */
+	if (kasan_quarantine_put(cache, object))
+		return true;
+
+	/*
+	 * Note: Keep per-object metadata to allow KASAN print stack traces for
+	 * use-after-free-before-realloc bugs.
+	 */
+
+	/* Let slab put the object onto the freelist. */
+	return false;
+}
+
+static inline bool check_page_allocation(void *ptr, unsigned long ip)
+{
+	if (ptr != page_address(virt_to_head_page(ptr))) {
+		kasan_report_invalid_free(ptr, ip, KASAN_REPORT_INVALID_FREE);
 		return true;
 	}
 
-	rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE);
-	kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
+	if (!kasan_byte_accessible(ptr)) {
+		kasan_report_invalid_free(ptr, ip, KASAN_REPORT_DOUBLE_FREE);
+		return true;
+	}
 
-	if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) ||
-			unlikely(!(cache->flags & SLAB_KASAN)))
-		return false;
+	return false;
+}
 
-	set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
-	quarantine_put(get_free_info(cache, object), cache);
+void __kasan_kfree_large(void *ptr, unsigned long ip)
+{
+	check_page_allocation(ptr, ip);
 
-	return IS_ENABLED(CONFIG_KASAN_GENERIC);
+	/* The object will be poisoned by kasan_poison_pages(). */
 }
 
-bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)
+static inline void unpoison_slab_object(struct kmem_cache *cache, void *object,
+					gfp_t flags, bool init)
 {
-	return __kasan_slab_free(cache, object, ip, true);
+	/*
+	 * Unpoison the whole object. For kmalloc() allocations,
+	 * poison_kmalloc_redzone() will do precise poisoning.
+	 */
+	kasan_unpoison(object, cache->object_size, init);
+
+	/* Save alloc info (if possible) for non-kmalloc() allocations. */
+	if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))
+		kasan_save_alloc_info(cache, object, flags);
 }
 
-static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
-				size_t size, gfp_t flags, bool krealloc)
+void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,
+					void *object, gfp_t flags, bool init)
 {
-	unsigned long redzone_start;
-	unsigned long redzone_end;
 	u8 tag;
+	void *tagged_object;
 
 	if (gfpflags_allow_blocking(flags))
-		quarantine_reduce();
+		kasan_quarantine_reduce();
 
 	if (unlikely(object == NULL))
 		return NULL;
 
-	redzone_start = round_up((unsigned long)(object + size),
-				KASAN_SHADOW_SCALE_SIZE);
-	redzone_end = round_up((unsigned long)object + cache->object_size,
-				KASAN_SHADOW_SCALE_SIZE);
+	if (is_kfence_address(object))
+		return (void *)object;
+
+	/*
+	 * Generate and assign random tag for tag-based modes.
+	 * Tag is ignored in set_tag() for the generic mode.
+	 */
+	tag = assign_tag(cache, object, false);
+	tagged_object = set_tag(object, tag);
+
+	/* Unpoison the object and save alloc info for non-kmalloc() allocations. */
+	unpoison_slab_object(cache, tagged_object, flags, init);
 
-	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-		tag = assign_tag(cache, object, false, krealloc);
+	return tagged_object;
+}
 
-	/* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */
-	kasan_unpoison_shadow(set_tag(object, tag), size);
-	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
-		KASAN_KMALLOC_REDZONE);
+static inline void poison_kmalloc_redzone(struct kmem_cache *cache,
+				const void *object, size_t size, gfp_t flags)
+{
+	unsigned long redzone_start;
+	unsigned long redzone_end;
 
-	if (cache->flags & SLAB_KASAN)
-		set_track(&get_alloc_info(cache, object)->alloc_track, flags);
+	/*
+	 * The redzone has byte-level precision for the generic mode.
+	 * Partially poison the last object granule to cover the unaligned
+	 * part of the redzone.
+	 */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+		kasan_poison_last_granule((void *)object, size);
+
+	/* Poison the aligned part of the redzone. */
+	redzone_start = round_up((unsigned long)(object + size),
+				KASAN_GRANULE_SIZE);
+	redzone_end = round_up((unsigned long)(object + cache->object_size),
+				KASAN_GRANULE_SIZE);
+	kasan_poison((void *)redzone_start, redzone_end - redzone_start,
+			   KASAN_SLAB_REDZONE, false);
+
+	/*
+	 * Save alloc info (if possible) for kmalloc() allocations.
+	 * This also rewrites the alloc info when called from kasan_krealloc().
+	 */
+	if (kasan_stack_collection_enabled() && is_kmalloc_cache(cache))
+		kasan_save_alloc_info(cache, (void *)object, flags);
 
-	return set_tag(object, tag);
 }
 
-void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object,
-				size_t size, gfp_t flags)
+void * __must_check __kasan_kmalloc(struct kmem_cache *cache, const void *object,
+					size_t size, gfp_t flags)
 {
-	return __kasan_kmalloc(cache, object, size, flags, false);
+	if (gfpflags_allow_blocking(flags))
+		kasan_quarantine_reduce();
+
+	if (unlikely(object == NULL))
+		return NULL;
+
+	if (is_kfence_address(object))
+		return (void *)object;
+
+	/* The object has already been unpoisoned by kasan_slab_alloc(). */
+	poison_kmalloc_redzone(cache, object, size, flags);
+
+	/* Keep the tag that was set by kasan_slab_alloc(). */
+	return (void *)object;
 }
-EXPORT_SYMBOL(kasan_kmalloc);
+EXPORT_SYMBOL(__kasan_kmalloc);
 
-void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
+static inline void poison_kmalloc_large_redzone(const void *ptr, size_t size,
 						gfp_t flags)
 {
-	struct page *page;
 	unsigned long redzone_start;
 	unsigned long redzone_end;
 
+	/*
+	 * The redzone has byte-level precision for the generic mode.
+	 * Partially poison the last object granule to cover the unaligned
+	 * part of the redzone.
+	 */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+		kasan_poison_last_granule(ptr, size);
+
+	/* Poison the aligned part of the redzone. */
+	redzone_start = round_up((unsigned long)(ptr + size), KASAN_GRANULE_SIZE);
+	redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr));
+	kasan_poison((void *)redzone_start, redzone_end - redzone_start,
+		     KASAN_PAGE_REDZONE, false);
+}
+
+void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
+						gfp_t flags)
+{
 	if (gfpflags_allow_blocking(flags))
-		quarantine_reduce();
+		kasan_quarantine_reduce();
 
 	if (unlikely(ptr == NULL))
 		return NULL;
 
-	page = virt_to_page(ptr);
-	redzone_start = round_up((unsigned long)(ptr + size),
-				KASAN_SHADOW_SCALE_SIZE);
-	redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
-
-	kasan_unpoison_shadow(ptr, size);
-	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
-		KASAN_PAGE_REDZONE);
+	/* The object has already been unpoisoned by kasan_unpoison_pages(). */
+	poison_kmalloc_large_redzone(ptr, size, flags);
 
+	/* Keep the tag that was set by alloc_pages(). */
 	return (void *)ptr;
 }
 
-void * __must_check kasan_krealloc(const void *object, size_t size, gfp_t flags)
+void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags)
 {
-	struct page *page;
+	struct slab *slab;
+
+	if (gfpflags_allow_blocking(flags))
+		kasan_quarantine_reduce();
 
 	if (unlikely(object == ZERO_SIZE_PTR))
 		return (void *)object;
 
-	page = virt_to_head_page(object);
+	if (is_kfence_address(object))
+		return (void *)object;
 
-	if (unlikely(!PageSlab(page)))
-		return kasan_kmalloc_large(object, size, flags);
+	/*
+	 * Unpoison the object's data.
+	 * Part of it might already have been unpoisoned, but it's unknown
+	 * how big that part is.
+	 */
+	kasan_unpoison(object, size, false);
+
+	slab = virt_to_slab(object);
+
+	/* Piggy-back on kmalloc() instrumentation to poison the redzone. */
+	if (unlikely(!slab))
+		poison_kmalloc_large_redzone(object, size, flags);
 	else
-		return __kasan_kmalloc(page->slab_cache, object, size,
-						flags, true);
+		poison_kmalloc_redzone(slab->slab_cache, object, size, flags);
+
+	return (void *)object;
 }
 
-void kasan_poison_kfree(void *ptr, unsigned long ip)
+bool __kasan_mempool_poison_pages(struct page *page, unsigned int order,
+				  unsigned long ip)
 {
-	struct page *page;
+	unsigned long *ptr;
 
-	page = virt_to_head_page(ptr);
+	if (unlikely(PageHighMem(page)))
+		return true;
 
-	if (unlikely(!PageSlab(page))) {
-		if (ptr != page_address(page)) {
-			kasan_report_invalid_free(ptr, ip);
-			return;
-		}
-		kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
-				KASAN_FREE_PAGE);
-	} else {
-		__kasan_slab_free(page->slab_cache, ptr, ip, false);
-	}
+	/* Bail out if allocation was excluded due to sampling. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
+	    page_kasan_tag(page) == KASAN_TAG_KERNEL)
+		return true;
+
+	ptr = page_address(page);
+
+	if (check_page_allocation(ptr, ip))
+		return false;
+
+	kasan_poison(ptr, PAGE_SIZE << order, KASAN_PAGE_FREE, false);
+
+	return true;
 }
 
-void kasan_kfree_large(void *ptr, unsigned long ip)
+void __kasan_mempool_unpoison_pages(struct page *page, unsigned int order,
+				    unsigned long ip)
 {
-	if (ptr != page_address(virt_to_head_page(ptr)))
-		kasan_report_invalid_free(ptr, ip);
-	/* The object will be poisoned by page_alloc. */
+	__kasan_unpoison_pages(page, order, false);
 }
 
-int kasan_module_alloc(void *addr, size_t size)
+bool __kasan_mempool_poison_object(void *ptr, unsigned long ip)
 {
-	void *ret;
-	size_t scaled_size;
-	size_t shadow_size;
-	unsigned long shadow_start;
-
-	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-	scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
-	shadow_size = round_up(scaled_size, PAGE_SIZE);
+	struct page *page = virt_to_page(ptr);
+	struct slab *slab;
 
-	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
-		return -EINVAL;
+	if (unlikely(PageLargeKmalloc(page))) {
+		if (check_page_allocation(ptr, ip))
+			return false;
+		kasan_poison(ptr, page_size(page), KASAN_PAGE_FREE, false);
+		return true;
+	}
 
-	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
-			shadow_start + shadow_size,
-			GFP_KERNEL,
-			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
-			__builtin_return_address(0));
+	if (is_kfence_address(ptr))
+		return true;
 
-	if (ret) {
-		__memset(ret, KASAN_SHADOW_INIT, shadow_size);
-		find_vm_area(addr)->flags |= VM_KASAN;
-		kmemleak_ignore(ret);
-		return 0;
-	}
+	slab = page_slab(page);
 
-	return -ENOMEM;
-}
+	if (check_slab_allocation(slab->slab_cache, ptr, ip))
+		return false;
 
-void kasan_free_shadow(const struct vm_struct *vm)
-{
-	if (vm->flags & VM_KASAN)
-		vfree(kasan_mem_to_shadow(vm->addr));
+	poison_slab_object(slab->slab_cache, ptr, false);
+	return true;
 }
 
-#ifdef CONFIG_MEMORY_HOTPLUG
-static bool shadow_mapped(unsigned long addr)
+void __kasan_mempool_unpoison_object(void *ptr, size_t size, unsigned long ip)
 {
-	pgd_t *pgd = pgd_offset_k(addr);
-	p4d_t *p4d;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
+	struct slab *slab;
+	gfp_t flags = 0; /* Might be executing under a lock. */
 
-	if (pgd_none(*pgd))
-		return false;
-	p4d = p4d_offset(pgd, addr);
-	if (p4d_none(*p4d))
-		return false;
-	pud = pud_offset(p4d, addr);
-	if (pud_none(*pud))
-		return false;
+	slab = virt_to_slab(ptr);
 
 	/*
-	 * We can't use pud_large() or pud_huge(), the first one is
-	 * arch-specific, the last one depends on HUGETLB_PAGE.  So let's abuse
-	 * pud_bad(), if pud is bad then it's bad because it's huge.
+	 * This function can be called for large kmalloc allocation that get
+	 * their memory from page_alloc.
 	 */
-	if (pud_bad(*pud))
-		return true;
-	pmd = pmd_offset(pud, addr);
-	if (pmd_none(*pmd))
-		return false;
-
-	if (pmd_bad(*pmd))
-		return true;
-	pte = pte_offset_kernel(pmd, addr);
-	return !pte_none(*pte);
-}
-
-static int __meminit kasan_mem_notifier(struct notifier_block *nb,
-			unsigned long action, void *data)
-{
-	struct memory_notify *mem_data = data;
-	unsigned long nr_shadow_pages, start_kaddr, shadow_start;
-	unsigned long shadow_end, shadow_size;
-
-	nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
-	start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
-	shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
-	shadow_size = nr_shadow_pages << PAGE_SHIFT;
-	shadow_end = shadow_start + shadow_size;
-
-	if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||
-		WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))
-		return NOTIFY_BAD;
-
-	switch (action) {
-	case MEM_GOING_ONLINE: {
-		void *ret;
-
-		/*
-		 * If shadow is mapped already than it must have been mapped
-		 * during the boot. This could happen if we onlining previously
-		 * offlined memory.
-		 */
-		if (shadow_mapped(shadow_start))
-			return NOTIFY_OK;
-
-		ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
-					shadow_end, GFP_KERNEL,
-					PAGE_KERNEL, VM_NO_GUARD,
-					pfn_to_nid(mem_data->start_pfn),
-					__builtin_return_address(0));
-		if (!ret)
-			return NOTIFY_BAD;
-
-		kmemleak_ignore(ret);
-		return NOTIFY_OK;
-	}
-	case MEM_CANCEL_ONLINE:
-	case MEM_OFFLINE: {
-		struct vm_struct *vm;
-
-		/*
-		 * shadow_start was either mapped during boot by kasan_init()
-		 * or during memory online by __vmalloc_node_range().
-		 * In the latter case we can use vfree() to free shadow.
-		 * Non-NULL result of the find_vm_area() will tell us if
-		 * that was the second case.
-		 *
-		 * Currently it's not possible to free shadow mapped
-		 * during boot by kasan_init(). It's because the code
-		 * to do that hasn't been written yet. So we'll just
-		 * leak the memory.
-		 */
-		vm = find_vm_area((void *)shadow_start);
-		if (vm)
-			vfree((void *)shadow_start);
-	}
+	if (unlikely(!slab)) {
+		kasan_unpoison(ptr, size, false);
+		poison_kmalloc_large_redzone(ptr, size, flags);
+		return;
 	}
 
-	return NOTIFY_OK;
-}
+	if (is_kfence_address(ptr))
+		return;
 
-static int __init kasan_memhotplug_init(void)
-{
-	hotplug_memory_notifier(kasan_mem_notifier, 0);
+	/* Unpoison the object and save alloc info for non-kmalloc() allocations. */
+	unpoison_slab_object(slab->slab_cache, ptr, flags, false);
 
-	return 0;
+	/* Poison the redzone and save alloc info for kmalloc() allocations. */
+	if (is_kmalloc_cache(slab->slab_cache))
+		poison_kmalloc_redzone(slab->slab_cache, ptr, size, flags);
 }
 
-core_initcall(kasan_memhotplug_init);
-#endif
+bool __kasan_check_byte(const void *address, unsigned long ip)
+{
+	if (!kasan_byte_accessible(address)) {
+		kasan_report(address, 1, false, ip);
+		return false;
+	}
+	return true;
+}