kasan: move common generic and tag-based code to common.c (bffa986c) · Commits · 戴 / test

mm/kasan/Makefile

+4 −1

Original line number	Diff line number	Diff line
		# SPDX-License-Identifier: GPL-2.0
		KASAN_SANITIZE := n
		UBSAN_SANITIZE_common.o := n
		UBSAN_SANITIZE_kasan.o := n
		KCOV_INSTRUMENT := n

		CFLAGS_REMOVE_kasan.o = -pg
		# Function splitter causes unnecessary splits in __asan_load1/__asan_store1
		# see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533

		CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
		CFLAGS_kasan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)

		obj-y := kasan.o report.o kasan_init.o quarantine.o
		obj-y := common.o kasan.o report.o kasan_init.o quarantine.o

mm/kasan/common.c

0 → 100644

+603 −0

Original line number	Diff line number	Diff line
		/*
		* This file contains common generic and tag-based 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>
		#include <linux/mm.h>
		#include <linux/module.h>
		#include <linux/printk.h>
		#include <linux/sched.h>
		#include <linux/sched/task_stack.h>
		#include <linux/slab.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)
		{
		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);
		}

		static inline void filter_irq_stacks(struct stack_trace *trace)
		{
		int i;

		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;
		}
		}

		static inline depot_stack_handle_t save_stack(gfp_t flags)
		{
		unsigned long entries[KASAN_STACK_DEPTH];
		struct stack_trace trace = {
		.nr_entries = 0,
		.entries = entries,
		.max_entries = KASAN_STACK_DEPTH,
		.skip = 0
		};

		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);
		}

		static inline void set_track(struct kasan_track *track, gfp_t flags)
		{
		track->pid = current->pid;
		track->stack = save_stack(flags);
		}

		void kasan_enable_current(void)
		{
		current->kasan_depth++;
		}

		void kasan_disable_current(void)
		{
		current->kasan_depth--;
		}

		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_);

		return __memmove(dest, src, len);
		}

		#undef memcpy
		void memcpy(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_);

		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;

		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)
		{
		kasan_poison_shadow(address, size, 0);

		if (size & KASAN_SHADOW_MASK) {
		u8 shadow = (u8 )kasan_mem_to_shadow(address + size);
		*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;

		kasan_unpoison_shadow(base, size);
		}

		/* 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);
		}

		/* Unpoison the stack for the current task beyond a watermark sp value. */
		asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
		{
		/*
		* Calculate the task stack base address. Avoid using 'current'
		* because this function is called by early resume code which hasn't
		* yet set up the percpu register (%gs).
		*/
		void base = (void )((unsigned long)watermark & ~(THREAD_SIZE - 1));

		kasan_unpoison_shadow(base, watermark - base);
		}

		/*
		* 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)
		{
		if (likely(!PageHighMem(page)))
		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)
		{
		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;
		int redzone_adjust;

		/* Add alloc meta. */
		cache->kasan_info.alloc_meta_offset = *size;
		*size += sizeof(struct kasan_alloc_meta);

		/* Add free meta. */
		if (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_adjust = optimal_redzone(cache->object_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 +
		optimal_redzone(cache->object_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);
		}

		struct kasan_alloc_meta get_alloc_info(struct kmem_cache cache,
		const void *object)
		{
		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;
		}

		void kasan_poison_slab(struct page *page)
		{
		kasan_poison_shadow(page_address(page),
		PAGE_SIZE << compound_order(page),
		KASAN_KMALLOC_REDZONE);
		}

		void kasan_unpoison_object_data(struct kmem_cache cache, void object)
		{
		kasan_unpoison_shadow(object, cache->object_size);
		}

		void kasan_poison_object_data(struct kmem_cache cache, void object)
		{
		kasan_poison_shadow(object,
		round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
		KASAN_KMALLOC_REDZONE);
		}

		void kasan_init_slab_obj(struct kmem_cache cache, const void *object)
		{
		struct kasan_alloc_meta *alloc_info;

		if (!(cache->flags & SLAB_KASAN))
		return (void *)object;

		alloc_info = get_alloc_info(cache, object);
		__memset(alloc_info, 0, sizeof(*alloc_info));

		return (void *)object;
		}

		void kasan_slab_alloc(struct kmem_cache cache, void *object, gfp_t flags)
		{
		return kasan_kmalloc(cache, object, cache->object_size, flags);
		}

		static bool __kasan_slab_free(struct kmem_cache cache, void object,
		unsigned long ip, bool quarantine)
		{
		s8 shadow_byte;
		unsigned long rounded_up_size;

		if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
		object)) {
		kasan_report_invalid_free(object, ip);
		return true;
		}

		/* RCU slabs could be legally used after free within the RCU period */
		if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
		return false;

		shadow_byte = READ_ONCE((s8 )kasan_mem_to_shadow(object));
		if (shadow_byte < 0 \|\| shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
		kasan_report_invalid_free(object, ip);
		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 (!quarantine \|\| unlikely(!(cache->flags & SLAB_KASAN)))
		return false;

		set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
		quarantine_put(get_free_info(cache, object), cache);
		return true;
		}

		bool kasan_slab_free(struct kmem_cache cache, void object, unsigned long ip)
		{
		return __kasan_slab_free(cache, object, ip, true);
		}

		void kasan_kmalloc(struct kmem_cache cache, const void *object, size_t size,
		gfp_t flags)
		{
		unsigned long redzone_start;
		unsigned long redzone_end;

		if (gfpflags_allow_blocking(flags))
		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);

		kasan_unpoison_shadow(object, size);
		kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
		KASAN_KMALLOC_REDZONE);

		if (cache->flags & SLAB_KASAN)
		set_track(&get_alloc_info(cache, object)->alloc_track, flags);

		return (void *)object;
		}
		EXPORT_SYMBOL(kasan_kmalloc);

		void kasan_kmalloc_large(const void ptr, size_t size, gfp_t flags)
		{
		struct page *page;
		unsigned long redzone_start;
		unsigned long redzone_end;

		if (gfpflags_allow_blocking(flags))
		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);

		return (void *)ptr;
		}

		void kasan_krealloc(const void object, size_t size, gfp_t flags)
		{
		struct page *page;

		if (unlikely(object == ZERO_SIZE_PTR))
		return (void *)object;

		page = virt_to_head_page(object);

		if (unlikely(!PageSlab(page)))
		return kasan_kmalloc_large(object, size, flags);
		else
		return kasan_kmalloc(page->slab_cache, object, size, flags);
		}

		void kasan_poison_kfree(void *ptr, unsigned long ip)
		{
		struct page *page;

		page = virt_to_head_page(ptr);

		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);
		}
		}

		void kasan_kfree_large(void *ptr, 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. */
		}

		int kasan_module_alloc(void *addr, size_t size)
		{
		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);

		if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
		return -EINVAL;

		ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
		shadow_start + shadow_size,
		GFP_KERNEL \| __GFP_ZERO,
		PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
		__builtin_return_address(0));

		if (ret) {
		find_vm_area(addr)->flags \|= VM_KASAN;
		kmemleak_ignore(ret);
		return 0;
		}

		return -ENOMEM;
		}

		void kasan_free_shadow(const struct vm_struct *vm)
		{
		if (vm->flags & VM_KASAN)
		vfree(kasan_mem_to_shadow(vm->addr));
		}

		#ifdef CONFIG_MEMORY_HOTPLUG
		static bool shadow_mapped(unsigned long addr)
		{
		pgd_t *pgd = pgd_offset_k(addr);
		p4d_t *p4d;
		pud_t *pud;
		pmd_t *pmd;
		pte_t *pte;

		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;

		/*
		* 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.
		*/
		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);
		}
		}

		return NOTIFY_OK;
		}

		static int __init kasan_memhotplug_init(void)
		{
		hotplug_memory_notifier(kasan_mem_notifier, 0);

		return 0;
		}

		core_initcall(kasan_memhotplug_init);
		#endif

mm/kasan/kasan.c

+2 −568

File changed.

Preview size limit exceeded, changes collapsed.

mm/kasan/kasan.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -105,6 +105,11 @@ static inline const void kasan_shadow_to_mem(const void shadow_addr)
		<< KASAN_SHADOW_SCALE_SHIFT);
		}

		void kasan_poison_shadow(const void *address, size_t size, u8 value);

		void check_memory_region(unsigned long addr, size_t size, bool write,
		unsigned long ret_ip);

		void kasan_report(unsigned long addr, size_t size,
		bool is_write, unsigned long ip);
		void kasan_report_invalid_free(void *object, unsigned long ip);

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