Commit bffa986c authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

kasan: move common generic and tag-based code to common.c

Tag-based KASAN reuses a significant part of the generic KASAN code, so
move the common parts to common.c without any functional changes.

Link: http://lkml.kernel.org/r/114064d002356e03bb8cc91f7835e20dc61b51d9.1544099024.git.andreyknvl@google.com

Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 12b22386
# 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
/*
* 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
/*
* This file contains shadow memory manipulation code.