shadow.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * This file contains KASAN runtime code that manages shadow memory for
  4 * generic and software tag-based KASAN modes.
  5 *
  6 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  7 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  8 *
  9 * Some code borrowed from https://github.com/xairy/kasan-prototype by
 10 *        Andrey Konovalov <andreyknvl@gmail.com>
 11 */
 12
 13#include <linux/init.h>
 14#include <linux/kasan.h>
 15#include <linux/kernel.h>
 16#include <linux/kfence.h>
 17#include <linux/kmemleak.h>
 18#include <linux/memory.h>
 19#include <linux/mm.h>
 20#include <linux/string.h>
 21#include <linux/types.h>
 22#include <linux/vmalloc.h>
 23
 24#include <asm/cacheflush.h>
 25#include <asm/tlbflush.h>
 26
 27#include "kasan.h"
 28
 29bool __kasan_check_read(const volatile void *p, unsigned int size)
 30{
 31	return kasan_check_range((void *)p, size, false, _RET_IP_);
 32}
 33EXPORT_SYMBOL(__kasan_check_read);
 34
 35bool __kasan_check_write(const volatile void *p, unsigned int size)
 36{
 37	return kasan_check_range((void *)p, size, true, _RET_IP_);
 38}
 39EXPORT_SYMBOL(__kasan_check_write);
 40
 41#if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY)
 42/*
 43 * CONFIG_GENERIC_ENTRY relies on compiler emitted mem*() calls to not be
 44 * instrumented. KASAN enabled toolchains should emit __asan_mem*() functions
 45 * for the sites they want to instrument.
 46 *
 47 * If we have a compiler that can instrument meminstrinsics, never override
 48 * these, so that non-instrumented files can safely consider them as builtins.
 49 */
 50#undef memset
 51void *memset(void *addr, int c, size_t len)
 52{
 53	if (!kasan_check_range(addr, len, true, _RET_IP_))
 54		return NULL;
 55
 56	return __memset(addr, c, len);
 57}
 58
 59#ifdef __HAVE_ARCH_MEMMOVE
 60#undef memmove
 61void *memmove(void *dest, const void *src, size_t len)
 62{
 63	if (!kasan_check_range(src, len, false, _RET_IP_) ||
 64	    !kasan_check_range(dest, len, true, _RET_IP_))
 65		return NULL;
 66
 67	return __memmove(dest, src, len);
 68}
 69#endif
 70
 71#undef memcpy
 72void *memcpy(void *dest, const void *src, size_t len)
 73{
 74	if (!kasan_check_range(src, len, false, _RET_IP_) ||
 75	    !kasan_check_range(dest, len, true, _RET_IP_))
 76		return NULL;
 77
 78	return __memcpy(dest, src, len);
 79}
 80#endif
 81
 82void *__asan_memset(void *addr, int c, ssize_t len)
 83{
 84	if (!kasan_check_range(addr, len, true, _RET_IP_))
 85		return NULL;
 86
 87	return __memset(addr, c, len);
 88}
 89EXPORT_SYMBOL(__asan_memset);
 90
 91#ifdef __HAVE_ARCH_MEMMOVE
 92void *__asan_memmove(void *dest, const void *src, ssize_t len)
 93{
 94	if (!kasan_check_range(src, len, false, _RET_IP_) ||
 95	    !kasan_check_range(dest, len, true, _RET_IP_))
 96		return NULL;
 97
 98	return __memmove(dest, src, len);
 99}
100EXPORT_SYMBOL(__asan_memmove);
101#endif
102
103void *__asan_memcpy(void *dest, const void *src, ssize_t len)
104{
105	if (!kasan_check_range(src, len, false, _RET_IP_) ||
106	    !kasan_check_range(dest, len, true, _RET_IP_))
107		return NULL;
108
109	return __memcpy(dest, src, len);
110}
111EXPORT_SYMBOL(__asan_memcpy);
112
113#ifdef CONFIG_KASAN_SW_TAGS
114void *__hwasan_memset(void *addr, int c, ssize_t len) __alias(__asan_memset);
115EXPORT_SYMBOL(__hwasan_memset);
116#ifdef __HAVE_ARCH_MEMMOVE
117void *__hwasan_memmove(void *dest, const void *src, ssize_t len) __alias(__asan_memmove);
118EXPORT_SYMBOL(__hwasan_memmove);
119#endif
120void *__hwasan_memcpy(void *dest, const void *src, ssize_t len) __alias(__asan_memcpy);
121EXPORT_SYMBOL(__hwasan_memcpy);
122#endif
123
124void kasan_poison(const void *addr, size_t size, u8 value, bool init)
125{
126	void *shadow_start, *shadow_end;
127
128	if (!kasan_enabled())
129		return;
130
131	/*
132	 * Perform shadow offset calculation based on untagged address, as
133	 * some of the callers (e.g. kasan_poison_new_object) pass tagged
134	 * addresses to this function.
135	 */
136	addr = kasan_reset_tag(addr);
137
138	if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
139		return;
140	if (WARN_ON(size & KASAN_GRANULE_MASK))
141		return;
142
143	shadow_start = kasan_mem_to_shadow(addr);
144	shadow_end = kasan_mem_to_shadow(addr + size);
145
146	__memset(shadow_start, value, shadow_end - shadow_start);
147}
148EXPORT_SYMBOL_GPL(kasan_poison);
149
150#ifdef CONFIG_KASAN_GENERIC
151void kasan_poison_last_granule(const void *addr, size_t size)
152{
153	if (!kasan_enabled())
154		return;
155
156	if (size & KASAN_GRANULE_MASK) {
157		u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size);
158		*shadow = size & KASAN_GRANULE_MASK;
159	}
160}
161#endif
162
163void kasan_unpoison(const void *addr, size_t size, bool init)
164{
165	u8 tag = get_tag(addr);
166
167	/*
168	 * Perform shadow offset calculation based on untagged address, as
169	 * some of the callers (e.g. kasan_unpoison_new_object) pass tagged
170	 * addresses to this function.
171	 */
172	addr = kasan_reset_tag(addr);
173
174	if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
175		return;
176
177	/* Unpoison all granules that cover the object. */
178	kasan_poison(addr, round_up(size, KASAN_GRANULE_SIZE), tag, false);
179
180	/* Partially poison the last granule for the generic mode. */
181	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
182		kasan_poison_last_granule(addr, size);
183}
184
185#ifdef CONFIG_MEMORY_HOTPLUG
186static bool shadow_mapped(unsigned long addr)
187{
188	pgd_t *pgd = pgd_offset_k(addr);
189	p4d_t *p4d;
190	pud_t *pud;
191	pmd_t *pmd;
192	pte_t *pte;
193
194	if (pgd_none(*pgd))
195		return false;
196	p4d = p4d_offset(pgd, addr);
197	if (p4d_none(*p4d))
198		return false;
199	pud = pud_offset(p4d, addr);
200	if (pud_none(*pud))
201		return false;
202	if (pud_leaf(*pud))
203		return true;
204	pmd = pmd_offset(pud, addr);
205	if (pmd_none(*pmd))
206		return false;
207	if (pmd_leaf(*pmd))
208		return true;
209	pte = pte_offset_kernel(pmd, addr);
210	return !pte_none(ptep_get(pte));
211}
212
213static int __meminit kasan_mem_notifier(struct notifier_block *nb,
214			unsigned long action, void *data)
215{
216	struct memory_notify *mem_data = data;
217	unsigned long nr_shadow_pages, start_kaddr, shadow_start;
218	unsigned long shadow_end, shadow_size;
219
220	nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
221	start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
222	shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
223	shadow_size = nr_shadow_pages << PAGE_SHIFT;
224	shadow_end = shadow_start + shadow_size;
225
226	if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
227		WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE))
228		return NOTIFY_BAD;
229
230	switch (action) {
231	case MEM_GOING_ONLINE: {
232		void *ret;
233
234		/*
235		 * If shadow is mapped already than it must have been mapped
236		 * during the boot. This could happen if we onlining previously
237		 * offlined memory.
238		 */
239		if (shadow_mapped(shadow_start))
240			return NOTIFY_OK;
241
242		ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
243					shadow_end, GFP_KERNEL,
244					PAGE_KERNEL, VM_NO_GUARD,
245					pfn_to_nid(mem_data->start_pfn),
246					__builtin_return_address(0));
247		if (!ret)
248			return NOTIFY_BAD;
249
250		kmemleak_ignore(ret);
251		return NOTIFY_OK;
252	}
253	case MEM_CANCEL_ONLINE:
254	case MEM_OFFLINE: {
255		struct vm_struct *vm;
256
257		/*
258		 * shadow_start was either mapped during boot by kasan_init()
259		 * or during memory online by __vmalloc_node_range().
260		 * In the latter case we can use vfree() to free shadow.
261		 * Non-NULL result of the find_vm_area() will tell us if
262		 * that was the second case.
263		 *
264		 * Currently it's not possible to free shadow mapped
265		 * during boot by kasan_init(). It's because the code
266		 * to do that hasn't been written yet. So we'll just
267		 * leak the memory.
268		 */
269		vm = find_vm_area((void *)shadow_start);
270		if (vm)
271			vfree((void *)shadow_start);
272	}
273	}
274
275	return NOTIFY_OK;
276}
277
278static int __init kasan_memhotplug_init(void)
279{
280	hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI);
281
282	return 0;
283}
284
285core_initcall(kasan_memhotplug_init);
286#endif
287
288#ifdef CONFIG_KASAN_VMALLOC
289
290void __init __weak kasan_populate_early_vm_area_shadow(void *start,
291						       unsigned long size)
292{
293}
294
295struct vmalloc_populate_data {
296	unsigned long start;
297	struct page **pages;
298};
299
300static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
301				      void *_data)
302{
303	struct vmalloc_populate_data *data = _data;
304	struct page *page;
305	pte_t pte;
306	int index;
307
308	arch_leave_lazy_mmu_mode();
309
310	index = PFN_DOWN(addr - data->start);
311	page = data->pages[index];
312	__memset(page_to_virt(page), KASAN_VMALLOC_INVALID, PAGE_SIZE);
313	pte = pfn_pte(page_to_pfn(page), PAGE_KERNEL);
314
315	spin_lock(&init_mm.page_table_lock);
316	if (likely(pte_none(ptep_get(ptep)))) {
317		set_pte_at(&init_mm, addr, ptep, pte);
318		data->pages[index] = NULL;
319	}
320	spin_unlock(&init_mm.page_table_lock);
321
322	arch_enter_lazy_mmu_mode();
323
324	return 0;
325}
326
327static void ___free_pages_bulk(struct page **pages, int nr_pages)
328{
329	int i;
330
331	for (i = 0; i < nr_pages; i++) {
332		if (pages[i]) {
333			__free_pages(pages[i], 0);
334			pages[i] = NULL;
335		}
336	}
337}
338
339static int ___alloc_pages_bulk(struct page **pages, int nr_pages, gfp_t gfp_mask)
340{
341	unsigned long nr_populated, nr_total = nr_pages;
342	struct page **page_array = pages;
343
344	while (nr_pages) {
345		nr_populated = alloc_pages_bulk(gfp_mask, nr_pages, pages);
346		if (!nr_populated) {
347			___free_pages_bulk(page_array, nr_total - nr_pages);
348			return -ENOMEM;
349		}
350		pages += nr_populated;
351		nr_pages -= nr_populated;
352	}
353
354	return 0;
355}
356
357static int __kasan_populate_vmalloc_do(unsigned long start, unsigned long end, gfp_t gfp_mask)
358{
359	unsigned long nr_pages, nr_total = PFN_UP(end - start);
360	struct vmalloc_populate_data data;
361	unsigned int flags;
362	int ret = 0;
363
364	data.pages = (struct page **)__get_free_page(gfp_mask | __GFP_ZERO);
365	if (!data.pages)
366		return -ENOMEM;
367
368	while (nr_total) {
369		nr_pages = min(nr_total, PAGE_SIZE / sizeof(data.pages[0]));
370		ret = ___alloc_pages_bulk(data.pages, nr_pages, gfp_mask);
371		if (ret)
372			break;
373
374		data.start = start;
375
376		/*
377		 * page tables allocations ignore external gfp mask, enforce it
378		 * by the scope API
379		 */
380		flags = memalloc_apply_gfp_scope(gfp_mask);
381		ret = apply_to_page_range(&init_mm, start, nr_pages * PAGE_SIZE,
382					  kasan_populate_vmalloc_pte, &data);
383		memalloc_restore_scope(flags);
384
385		___free_pages_bulk(data.pages, nr_pages);
386		if (ret)
387			break;
388
389		start += nr_pages * PAGE_SIZE;
390		nr_total -= nr_pages;
391	}
392
393	free_page((unsigned long)data.pages);
394
395	return ret;
396}
397
398int __kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask)
399{
400	unsigned long shadow_start, shadow_end;
401	int ret;
402
403	if (!is_vmalloc_or_module_addr((void *)addr))
404		return 0;
405
406	shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr);
407	shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size);
408
409	/*
410	 * User Mode Linux maps enough shadow memory for all of virtual memory
411	 * at boot, so doesn't need to allocate more on vmalloc, just clear it.
412	 *
413	 * The remaining CONFIG_UML checks in this file exist for the same
414	 * reason.
415	 */
416	if (IS_ENABLED(CONFIG_UML)) {
417		__memset((void *)shadow_start, KASAN_VMALLOC_INVALID, shadow_end - shadow_start);
418		return 0;
419	}
420
421	shadow_start = PAGE_ALIGN_DOWN(shadow_start);
422	shadow_end = PAGE_ALIGN(shadow_end);
423
424	ret = __kasan_populate_vmalloc_do(shadow_start, shadow_end, gfp_mask);
425	if (ret)
426		return ret;
427
428	flush_cache_vmap(shadow_start, shadow_end);
429
430	/*
431	 * We need to be careful about inter-cpu effects here. Consider:
432	 *
433	 *   CPU#0				  CPU#1
434	 * WRITE_ONCE(p, vmalloc(100));		while (x = READ_ONCE(p)) ;
435	 *					p[99] = 1;
436	 *
437	 * With compiler instrumentation, that ends up looking like this:
438	 *
439	 *   CPU#0				  CPU#1
440	 * // vmalloc() allocates memory
441	 * // let a = area->addr
442	 * // we reach kasan_populate_vmalloc
443	 * // and call kasan_unpoison:
444	 * STORE shadow(a), unpoison_val
445	 * ...
446	 * STORE shadow(a+99), unpoison_val	x = LOAD p
447	 * // rest of vmalloc process		<data dependency>
448	 * STORE p, a				LOAD shadow(x+99)
449	 *
450	 * If there is no barrier between the end of unpoisoning the shadow
451	 * and the store of the result to p, the stores could be committed
452	 * in a different order by CPU#0, and CPU#1 could erroneously observe
453	 * poison in the shadow.
454	 *
455	 * We need some sort of barrier between the stores.
456	 *
457	 * In the vmalloc() case, this is provided by a smp_wmb() in
458	 * clear_vm_uninitialized_flag(). In the per-cpu allocator and in
459	 * get_vm_area() and friends, the caller gets shadow allocated but
460	 * doesn't have any pages mapped into the virtual address space that
461	 * has been reserved. Mapping those pages in will involve taking and
462	 * releasing a page-table lock, which will provide the barrier.
463	 */
464
465	return 0;
466}
467
468static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
469					void *unused)
470{
471	pte_t pte;
472	int none;
473
474	arch_leave_lazy_mmu_mode();
475
476	spin_lock(&init_mm.page_table_lock);
477	pte = ptep_get(ptep);
478	none = pte_none(pte);
479	if (likely(!none))
480		pte_clear(&init_mm, addr, ptep);
481	spin_unlock(&init_mm.page_table_lock);
482
483	if (likely(!none))
484		__free_page(pfn_to_page(pte_pfn(pte)));
485
486	arch_enter_lazy_mmu_mode();
487
488	return 0;
489}
490
491/*
492 * Release the backing for the vmalloc region [start, end), which
493 * lies within the free region [free_region_start, free_region_end).
494 *
495 * This can be run lazily, long after the region was freed. It runs
496 * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap
497 * infrastructure.
498 *
499 * How does this work?
500 * -------------------
501 *
502 * We have a region that is page aligned, labeled as A.
503 * That might not map onto the shadow in a way that is page-aligned:
504 *
505 *                    start                     end
506 *                    v                         v
507 * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc
508 *  -------- -------- --------          -------- --------
509 *      |        |       |                 |        |
510 *      |        |       |         /-------/        |
511 *      \-------\|/------/         |/---------------/
512 *              |||                ||
513 *             |??AAAAAA|AAAAAAAA|AA??????|                < shadow
514 *                 (1)      (2)      (3)
515 *
516 * First we align the start upwards and the end downwards, so that the
517 * shadow of the region aligns with shadow page boundaries. In the
518 * example, this gives us the shadow page (2). This is the shadow entirely
519 * covered by this allocation.
520 *
521 * Then we have the tricky bits. We want to know if we can free the
522 * partially covered shadow pages - (1) and (3) in the example. For this,
523 * we are given the start and end of the free region that contains this
524 * allocation. Extending our previous example, we could have:
525 *
526 *  free_region_start                                    free_region_end
527 *  |                 start                     end      |
528 *  v                 v                         v        v
529 * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc
530 *  -------- -------- --------          -------- --------
531 *      |        |       |                 |        |
532 *      |        |       |         /-------/        |
533 *      \-------\|/------/         |/---------------/
534 *              |||                ||
535 *             |FFAAAAAA|AAAAAAAA|AAF?????|                < shadow
536 *                 (1)      (2)      (3)
537 *
538 * Once again, we align the start of the free region up, and the end of
539 * the free region down so that the shadow is page aligned. So we can free
540 * page (1) - we know no allocation currently uses anything in that page,
541 * because all of it is in the vmalloc free region. But we cannot free
542 * page (3), because we can't be sure that the rest of it is unused.
543 *
544 * We only consider pages that contain part of the original region for
545 * freeing: we don't try to free other pages from the free region or we'd
546 * end up trying to free huge chunks of virtual address space.
547 *
548 * Concurrency
549 * -----------
550 *
551 * How do we know that we're not freeing a page that is simultaneously
552 * being used for a fresh allocation in kasan_populate_vmalloc(_pte)?
553 *
554 * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running
555 * at the same time. While we run under free_vmap_area_lock, the population
556 * code does not.
557 *
558 * free_vmap_area_lock instead operates to ensure that the larger range
559 * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and
560 * the per-cpu region-finding algorithm both run under free_vmap_area_lock,
561 * no space identified as free will become used while we are running. This
562 * means that so long as we are careful with alignment and only free shadow
563 * pages entirely covered by the free region, we will not run in to any
564 * trouble - any simultaneous allocations will be for disjoint regions.
565 */
566void __kasan_release_vmalloc(unsigned long start, unsigned long end,
567			   unsigned long free_region_start,
568			   unsigned long free_region_end,
569			   unsigned long flags)
570{
571	void *shadow_start, *shadow_end;
572	unsigned long region_start, region_end;
573	unsigned long size;
574
575	region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);
576	region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE);
577
578	free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE);
579
580	if (start != region_start &&
581	    free_region_start < region_start)
582		region_start -= KASAN_MEMORY_PER_SHADOW_PAGE;
583
584	free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE);
585
586	if (end != region_end &&
587	    free_region_end > region_end)
588		region_end += KASAN_MEMORY_PER_SHADOW_PAGE;
589
590	shadow_start = kasan_mem_to_shadow((void *)region_start);
591	shadow_end = kasan_mem_to_shadow((void *)region_end);
592
593	if (shadow_end > shadow_start) {
594		size = shadow_end - shadow_start;
595		if (IS_ENABLED(CONFIG_UML)) {
596			__memset(shadow_start, KASAN_SHADOW_INIT, shadow_end - shadow_start);
597			return;
598		}
599
600
601		if (flags & KASAN_VMALLOC_PAGE_RANGE)
602			apply_to_existing_page_range(&init_mm,
603					     (unsigned long)shadow_start,
604					     size, kasan_depopulate_vmalloc_pte,
605					     NULL);
606
607		if (flags & KASAN_VMALLOC_TLB_FLUSH)
608			flush_tlb_kernel_range((unsigned long)shadow_start,
609					       (unsigned long)shadow_end);
610	}
611}
612
613void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
614			       kasan_vmalloc_flags_t flags)
615{
616	/*
617	 * Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC
618	 * mappings, so the KASAN_VMALLOC_VM_ALLOC flag is ignored.
619	 * Software KASAN modes can't optimize zeroing memory by combining it
620	 * with setting memory tags, so the KASAN_VMALLOC_INIT flag is ignored.
621	 */
622
623	if (!is_vmalloc_or_module_addr(start))
624		return (void *)start;
625
626	/*
627	 * Don't tag executable memory with the tag-based mode.
628	 * The kernel doesn't tolerate having the PC register tagged.
629	 */
630	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) &&
631	    !(flags & KASAN_VMALLOC_PROT_NORMAL))
632		return (void *)start;
633
634	if (unlikely(!(flags & KASAN_VMALLOC_KEEP_TAG)))
635		start = set_tag(start, kasan_random_tag());
636
637	kasan_unpoison(start, size, false);
638	return (void *)start;
639}
640
641/*
642 * Poison the shadow for a vmalloc region. Called as part of the
643 * freeing process at the time the region is freed.
644 */
645void __kasan_poison_vmalloc(const void *start, unsigned long size)
646{
647	if (!is_vmalloc_or_module_addr(start))
648		return;
649
650	size = round_up(size, KASAN_GRANULE_SIZE);
651	kasan_poison(start, size, KASAN_VMALLOC_INVALID, false);
652}
653
654#else /* CONFIG_KASAN_VMALLOC */
655
656int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask)
657{
658	void *ret;
659	size_t scaled_size;
660	size_t shadow_size;
661	unsigned long shadow_start;
662
663	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
664	scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
665				KASAN_SHADOW_SCALE_SHIFT;
666	shadow_size = round_up(scaled_size, PAGE_SIZE);
667
668	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
669		return -EINVAL;
670
671	if (IS_ENABLED(CONFIG_UML)) {
672		__memset((void *)shadow_start, KASAN_SHADOW_INIT, shadow_size);
673		return 0;
674	}
675
676	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
677			shadow_start + shadow_size,
678			GFP_KERNEL,
679			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
680			__builtin_return_address(0));
681
682	if (ret) {
683		struct vm_struct *vm = find_vm_area(addr);
684		__memset(ret, KASAN_SHADOW_INIT, shadow_size);
685		vm->flags |= VM_KASAN;
686		kmemleak_ignore(ret);
687
688		if (vm->flags & VM_DEFER_KMEMLEAK)
689			kmemleak_vmalloc(vm, size, gfp_mask);
690
691		return 0;
692	}
693
694	return -ENOMEM;
695}
696
697void kasan_free_module_shadow(const struct vm_struct *vm)
698{
699	if (IS_ENABLED(CONFIG_UML))
700		return;
701
702	if (vm->flags & VM_KASAN)
703		vfree(kasan_mem_to_shadow(vm->addr));
704}
705
706#endif