xref: /openbmc/linux/mm/kasan/shadow.c (revision c33c7948)
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 
__kasan_check_read(const volatile void * p,unsigned int size)29 bool __kasan_check_read(const volatile void *p, unsigned int size)
30 {
31 	return kasan_check_range((void *)p, size, false, _RET_IP_);
32 }
33 EXPORT_SYMBOL(__kasan_check_read);
34 
__kasan_check_write(const volatile void * p,unsigned int size)35 bool __kasan_check_write(const volatile void *p, unsigned int size)
36 {
37 	return kasan_check_range((void *)p, size, true, _RET_IP_);
38 }
39 EXPORT_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
memset(void * addr,int c,size_t len)51 void *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
memmove(void * dest,const void * src,size_t len)61 void *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
memcpy(void * dest,const void * src,size_t len)72 void *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 
__asan_memset(void * addr,int c,ssize_t len)82 void *__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 }
89 EXPORT_SYMBOL(__asan_memset);
90 
91 #ifdef __HAVE_ARCH_MEMMOVE
__asan_memmove(void * dest,const void * src,ssize_t len)92 void *__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 }
100 EXPORT_SYMBOL(__asan_memmove);
101 #endif
102 
__asan_memcpy(void * dest,const void * src,ssize_t len)103 void *__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 }
111 EXPORT_SYMBOL(__asan_memcpy);
112 
113 #ifdef CONFIG_KASAN_SW_TAGS
114 void *__hwasan_memset(void *addr, int c, ssize_t len) __alias(__asan_memset);
115 EXPORT_SYMBOL(__hwasan_memset);
116 #ifdef __HAVE_ARCH_MEMMOVE
117 void *__hwasan_memmove(void *dest, const void *src, ssize_t len) __alias(__asan_memmove);
118 EXPORT_SYMBOL(__hwasan_memmove);
119 #endif
120 void *__hwasan_memcpy(void *dest, const void *src, ssize_t len) __alias(__asan_memcpy);
121 EXPORT_SYMBOL(__hwasan_memcpy);
122 #endif
123 
kasan_poison(const void * addr,size_t size,u8 value,bool init)124 void kasan_poison(const void *addr, size_t size, u8 value, bool init)
125 {
126 	void *shadow_start, *shadow_end;
127 
128 	if (!kasan_arch_is_ready())
129 		return;
130 
131 	/*
132 	 * Perform shadow offset calculation based on untagged address, as
133 	 * some of the callers (e.g. kasan_poison_object_data) pass tagged
134 	 * addresses to this function.
135 	 */
136 	addr = kasan_reset_tag(addr);
137 
138 	/* Skip KFENCE memory if called explicitly outside of sl*b. */
139 	if (is_kfence_address(addr))
140 		return;
141 
142 	if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
143 		return;
144 	if (WARN_ON(size & KASAN_GRANULE_MASK))
145 		return;
146 
147 	shadow_start = kasan_mem_to_shadow(addr);
148 	shadow_end = kasan_mem_to_shadow(addr + size);
149 
150 	__memset(shadow_start, value, shadow_end - shadow_start);
151 }
152 EXPORT_SYMBOL(kasan_poison);
153 
154 #ifdef CONFIG_KASAN_GENERIC
kasan_poison_last_granule(const void * addr,size_t size)155 void kasan_poison_last_granule(const void *addr, size_t size)
156 {
157 	if (!kasan_arch_is_ready())
158 		return;
159 
160 	if (size & KASAN_GRANULE_MASK) {
161 		u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size);
162 		*shadow = size & KASAN_GRANULE_MASK;
163 	}
164 }
165 #endif
166 
kasan_unpoison(const void * addr,size_t size,bool init)167 void kasan_unpoison(const void *addr, size_t size, bool init)
168 {
169 	u8 tag = get_tag(addr);
170 
171 	/*
172 	 * Perform shadow offset calculation based on untagged address, as
173 	 * some of the callers (e.g. kasan_unpoison_object_data) pass tagged
174 	 * addresses to this function.
175 	 */
176 	addr = kasan_reset_tag(addr);
177 
178 	/*
179 	 * Skip KFENCE memory if called explicitly outside of sl*b. Also note
180 	 * that calls to ksize(), where size is not a multiple of machine-word
181 	 * size, would otherwise poison the invalid portion of the word.
182 	 */
183 	if (is_kfence_address(addr))
184 		return;
185 
186 	if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
187 		return;
188 
189 	/* Unpoison all granules that cover the object. */
190 	kasan_poison(addr, round_up(size, KASAN_GRANULE_SIZE), tag, false);
191 
192 	/* Partially poison the last granule for the generic mode. */
193 	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
194 		kasan_poison_last_granule(addr, size);
195 }
196 
197 #ifdef CONFIG_MEMORY_HOTPLUG
shadow_mapped(unsigned long addr)198 static bool shadow_mapped(unsigned long addr)
199 {
200 	pgd_t *pgd = pgd_offset_k(addr);
201 	p4d_t *p4d;
202 	pud_t *pud;
203 	pmd_t *pmd;
204 	pte_t *pte;
205 
206 	if (pgd_none(*pgd))
207 		return false;
208 	p4d = p4d_offset(pgd, addr);
209 	if (p4d_none(*p4d))
210 		return false;
211 	pud = pud_offset(p4d, addr);
212 	if (pud_none(*pud))
213 		return false;
214 
215 	/*
216 	 * We can't use pud_large() or pud_huge(), the first one is
217 	 * arch-specific, the last one depends on HUGETLB_PAGE.  So let's abuse
218 	 * pud_bad(), if pud is bad then it's bad because it's huge.
219 	 */
220 	if (pud_bad(*pud))
221 		return true;
222 	pmd = pmd_offset(pud, addr);
223 	if (pmd_none(*pmd))
224 		return false;
225 
226 	if (pmd_bad(*pmd))
227 		return true;
228 	pte = pte_offset_kernel(pmd, addr);
229 	return !pte_none(ptep_get(pte));
230 }
231 
kasan_mem_notifier(struct notifier_block * nb,unsigned long action,void * data)232 static int __meminit kasan_mem_notifier(struct notifier_block *nb,
233 			unsigned long action, void *data)
234 {
235 	struct memory_notify *mem_data = data;
236 	unsigned long nr_shadow_pages, start_kaddr, shadow_start;
237 	unsigned long shadow_end, shadow_size;
238 
239 	nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
240 	start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
241 	shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
242 	shadow_size = nr_shadow_pages << PAGE_SHIFT;
243 	shadow_end = shadow_start + shadow_size;
244 
245 	if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
246 		WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE))
247 		return NOTIFY_BAD;
248 
249 	switch (action) {
250 	case MEM_GOING_ONLINE: {
251 		void *ret;
252 
253 		/*
254 		 * If shadow is mapped already than it must have been mapped
255 		 * during the boot. This could happen if we onlining previously
256 		 * offlined memory.
257 		 */
258 		if (shadow_mapped(shadow_start))
259 			return NOTIFY_OK;
260 
261 		ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
262 					shadow_end, GFP_KERNEL,
263 					PAGE_KERNEL, VM_NO_GUARD,
264 					pfn_to_nid(mem_data->start_pfn),
265 					__builtin_return_address(0));
266 		if (!ret)
267 			return NOTIFY_BAD;
268 
269 		kmemleak_ignore(ret);
270 		return NOTIFY_OK;
271 	}
272 	case MEM_CANCEL_ONLINE:
273 	case MEM_OFFLINE: {
274 		struct vm_struct *vm;
275 
276 		/*
277 		 * shadow_start was either mapped during boot by kasan_init()
278 		 * or during memory online by __vmalloc_node_range().
279 		 * In the latter case we can use vfree() to free shadow.
280 		 * Non-NULL result of the find_vm_area() will tell us if
281 		 * that was the second case.
282 		 *
283 		 * Currently it's not possible to free shadow mapped
284 		 * during boot by kasan_init(). It's because the code
285 		 * to do that hasn't been written yet. So we'll just
286 		 * leak the memory.
287 		 */
288 		vm = find_vm_area((void *)shadow_start);
289 		if (vm)
290 			vfree((void *)shadow_start);
291 	}
292 	}
293 
294 	return NOTIFY_OK;
295 }
296 
kasan_memhotplug_init(void)297 static int __init kasan_memhotplug_init(void)
298 {
299 	hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI);
300 
301 	return 0;
302 }
303 
304 core_initcall(kasan_memhotplug_init);
305 #endif
306 
307 #ifdef CONFIG_KASAN_VMALLOC
308 
kasan_populate_early_vm_area_shadow(void * start,unsigned long size)309 void __init __weak kasan_populate_early_vm_area_shadow(void *start,
310 						       unsigned long size)
311 {
312 }
313 
kasan_populate_vmalloc_pte(pte_t * ptep,unsigned long addr,void * unused)314 static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
315 				      void *unused)
316 {
317 	unsigned long page;
318 	pte_t pte;
319 
320 	if (likely(!pte_none(ptep_get(ptep))))
321 		return 0;
322 
323 	page = __get_free_page(GFP_KERNEL);
324 	if (!page)
325 		return -ENOMEM;
326 
327 	memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
328 	pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
329 
330 	spin_lock(&init_mm.page_table_lock);
331 	if (likely(pte_none(ptep_get(ptep)))) {
332 		set_pte_at(&init_mm, addr, ptep, pte);
333 		page = 0;
334 	}
335 	spin_unlock(&init_mm.page_table_lock);
336 	if (page)
337 		free_page(page);
338 	return 0;
339 }
340 
kasan_populate_vmalloc(unsigned long addr,unsigned long size)341 int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
342 {
343 	unsigned long shadow_start, shadow_end;
344 	int ret;
345 
346 	if (!kasan_arch_is_ready())
347 		return 0;
348 
349 	if (!is_vmalloc_or_module_addr((void *)addr))
350 		return 0;
351 
352 	shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr);
353 	shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size);
354 
355 	/*
356 	 * User Mode Linux maps enough shadow memory for all of virtual memory
357 	 * at boot, so doesn't need to allocate more on vmalloc, just clear it.
358 	 *
359 	 * The remaining CONFIG_UML checks in this file exist for the same
360 	 * reason.
361 	 */
362 	if (IS_ENABLED(CONFIG_UML)) {
363 		__memset((void *)shadow_start, KASAN_VMALLOC_INVALID, shadow_end - shadow_start);
364 		return 0;
365 	}
366 
367 	shadow_start = PAGE_ALIGN_DOWN(shadow_start);
368 	shadow_end = PAGE_ALIGN(shadow_end);
369 
370 	ret = apply_to_page_range(&init_mm, shadow_start,
371 				  shadow_end - shadow_start,
372 				  kasan_populate_vmalloc_pte, NULL);
373 	if (ret)
374 		return ret;
375 
376 	flush_cache_vmap(shadow_start, shadow_end);
377 
378 	/*
379 	 * We need to be careful about inter-cpu effects here. Consider:
380 	 *
381 	 *   CPU#0				  CPU#1
382 	 * WRITE_ONCE(p, vmalloc(100));		while (x = READ_ONCE(p)) ;
383 	 *					p[99] = 1;
384 	 *
385 	 * With compiler instrumentation, that ends up looking like this:
386 	 *
387 	 *   CPU#0				  CPU#1
388 	 * // vmalloc() allocates memory
389 	 * // let a = area->addr
390 	 * // we reach kasan_populate_vmalloc
391 	 * // and call kasan_unpoison:
392 	 * STORE shadow(a), unpoison_val
393 	 * ...
394 	 * STORE shadow(a+99), unpoison_val	x = LOAD p
395 	 * // rest of vmalloc process		<data dependency>
396 	 * STORE p, a				LOAD shadow(x+99)
397 	 *
398 	 * If there is no barrier between the end of unpoisoning the shadow
399 	 * and the store of the result to p, the stores could be committed
400 	 * in a different order by CPU#0, and CPU#1 could erroneously observe
401 	 * poison in the shadow.
402 	 *
403 	 * We need some sort of barrier between the stores.
404 	 *
405 	 * In the vmalloc() case, this is provided by a smp_wmb() in
406 	 * clear_vm_uninitialized_flag(). In the per-cpu allocator and in
407 	 * get_vm_area() and friends, the caller gets shadow allocated but
408 	 * doesn't have any pages mapped into the virtual address space that
409 	 * has been reserved. Mapping those pages in will involve taking and
410 	 * releasing a page-table lock, which will provide the barrier.
411 	 */
412 
413 	return 0;
414 }
415 
kasan_depopulate_vmalloc_pte(pte_t * ptep,unsigned long addr,void * unused)416 static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
417 					void *unused)
418 {
419 	unsigned long page;
420 
421 	page = (unsigned long)__va(pte_pfn(ptep_get(ptep)) << PAGE_SHIFT);
422 
423 	spin_lock(&init_mm.page_table_lock);
424 
425 	if (likely(!pte_none(ptep_get(ptep)))) {
426 		pte_clear(&init_mm, addr, ptep);
427 		free_page(page);
428 	}
429 	spin_unlock(&init_mm.page_table_lock);
430 
431 	return 0;
432 }
433 
434 /*
435  * Release the backing for the vmalloc region [start, end), which
436  * lies within the free region [free_region_start, free_region_end).
437  *
438  * This can be run lazily, long after the region was freed. It runs
439  * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap
440  * infrastructure.
441  *
442  * How does this work?
443  * -------------------
444  *
445  * We have a region that is page aligned, labeled as A.
446  * That might not map onto the shadow in a way that is page-aligned:
447  *
448  *                    start                     end
449  *                    v                         v
450  * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc
451  *  -------- -------- --------          -------- --------
452  *      |        |       |                 |        |
453  *      |        |       |         /-------/        |
454  *      \-------\|/------/         |/---------------/
455  *              |||                ||
456  *             |??AAAAAA|AAAAAAAA|AA??????|                < shadow
457  *                 (1)      (2)      (3)
458  *
459  * First we align the start upwards and the end downwards, so that the
460  * shadow of the region aligns with shadow page boundaries. In the
461  * example, this gives us the shadow page (2). This is the shadow entirely
462  * covered by this allocation.
463  *
464  * Then we have the tricky bits. We want to know if we can free the
465  * partially covered shadow pages - (1) and (3) in the example. For this,
466  * we are given the start and end of the free region that contains this
467  * allocation. Extending our previous example, we could have:
468  *
469  *  free_region_start                                    free_region_end
470  *  |                 start                     end      |
471  *  v                 v                         v        v
472  * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc
473  *  -------- -------- --------          -------- --------
474  *      |        |       |                 |        |
475  *      |        |       |         /-------/        |
476  *      \-------\|/------/         |/---------------/
477  *              |||                ||
478  *             |FFAAAAAA|AAAAAAAA|AAF?????|                < shadow
479  *                 (1)      (2)      (3)
480  *
481  * Once again, we align the start of the free region up, and the end of
482  * the free region down so that the shadow is page aligned. So we can free
483  * page (1) - we know no allocation currently uses anything in that page,
484  * because all of it is in the vmalloc free region. But we cannot free
485  * page (3), because we can't be sure that the rest of it is unused.
486  *
487  * We only consider pages that contain part of the original region for
488  * freeing: we don't try to free other pages from the free region or we'd
489  * end up trying to free huge chunks of virtual address space.
490  *
491  * Concurrency
492  * -----------
493  *
494  * How do we know that we're not freeing a page that is simultaneously
495  * being used for a fresh allocation in kasan_populate_vmalloc(_pte)?
496  *
497  * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running
498  * at the same time. While we run under free_vmap_area_lock, the population
499  * code does not.
500  *
501  * free_vmap_area_lock instead operates to ensure that the larger range
502  * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and
503  * the per-cpu region-finding algorithm both run under free_vmap_area_lock,
504  * no space identified as free will become used while we are running. This
505  * means that so long as we are careful with alignment and only free shadow
506  * pages entirely covered by the free region, we will not run in to any
507  * trouble - any simultaneous allocations will be for disjoint regions.
508  */
kasan_release_vmalloc(unsigned long start,unsigned long end,unsigned long free_region_start,unsigned long free_region_end)509 void kasan_release_vmalloc(unsigned long start, unsigned long end,
510 			   unsigned long free_region_start,
511 			   unsigned long free_region_end)
512 {
513 	void *shadow_start, *shadow_end;
514 	unsigned long region_start, region_end;
515 	unsigned long size;
516 
517 	if (!kasan_arch_is_ready())
518 		return;
519 
520 	region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);
521 	region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE);
522 
523 	free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE);
524 
525 	if (start != region_start &&
526 	    free_region_start < region_start)
527 		region_start -= KASAN_MEMORY_PER_SHADOW_PAGE;
528 
529 	free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE);
530 
531 	if (end != region_end &&
532 	    free_region_end > region_end)
533 		region_end += KASAN_MEMORY_PER_SHADOW_PAGE;
534 
535 	shadow_start = kasan_mem_to_shadow((void *)region_start);
536 	shadow_end = kasan_mem_to_shadow((void *)region_end);
537 
538 	if (shadow_end > shadow_start) {
539 		size = shadow_end - shadow_start;
540 		if (IS_ENABLED(CONFIG_UML)) {
541 			__memset(shadow_start, KASAN_SHADOW_INIT, shadow_end - shadow_start);
542 			return;
543 		}
544 		apply_to_existing_page_range(&init_mm,
545 					     (unsigned long)shadow_start,
546 					     size, kasan_depopulate_vmalloc_pte,
547 					     NULL);
548 		flush_tlb_kernel_range((unsigned long)shadow_start,
549 				       (unsigned long)shadow_end);
550 	}
551 }
552 
__kasan_unpoison_vmalloc(const void * start,unsigned long size,kasan_vmalloc_flags_t flags)553 void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
554 			       kasan_vmalloc_flags_t flags)
555 {
556 	/*
557 	 * Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC
558 	 * mappings, so the KASAN_VMALLOC_VM_ALLOC flag is ignored.
559 	 * Software KASAN modes can't optimize zeroing memory by combining it
560 	 * with setting memory tags, so the KASAN_VMALLOC_INIT flag is ignored.
561 	 */
562 
563 	if (!kasan_arch_is_ready())
564 		return (void *)start;
565 
566 	if (!is_vmalloc_or_module_addr(start))
567 		return (void *)start;
568 
569 	/*
570 	 * Don't tag executable memory with the tag-based mode.
571 	 * The kernel doesn't tolerate having the PC register tagged.
572 	 */
573 	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) &&
574 	    !(flags & KASAN_VMALLOC_PROT_NORMAL))
575 		return (void *)start;
576 
577 	start = set_tag(start, kasan_random_tag());
578 	kasan_unpoison(start, size, false);
579 	return (void *)start;
580 }
581 
582 /*
583  * Poison the shadow for a vmalloc region. Called as part of the
584  * freeing process at the time the region is freed.
585  */
__kasan_poison_vmalloc(const void * start,unsigned long size)586 void __kasan_poison_vmalloc(const void *start, unsigned long size)
587 {
588 	if (!kasan_arch_is_ready())
589 		return;
590 
591 	if (!is_vmalloc_or_module_addr(start))
592 		return;
593 
594 	size = round_up(size, KASAN_GRANULE_SIZE);
595 	kasan_poison(start, size, KASAN_VMALLOC_INVALID, false);
596 }
597 
598 #else /* CONFIG_KASAN_VMALLOC */
599 
kasan_alloc_module_shadow(void * addr,size_t size,gfp_t gfp_mask)600 int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask)
601 {
602 	void *ret;
603 	size_t scaled_size;
604 	size_t shadow_size;
605 	unsigned long shadow_start;
606 
607 	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
608 	scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
609 				KASAN_SHADOW_SCALE_SHIFT;
610 	shadow_size = round_up(scaled_size, PAGE_SIZE);
611 
612 	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
613 		return -EINVAL;
614 
615 	if (IS_ENABLED(CONFIG_UML)) {
616 		__memset((void *)shadow_start, KASAN_SHADOW_INIT, shadow_size);
617 		return 0;
618 	}
619 
620 	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
621 			shadow_start + shadow_size,
622 			GFP_KERNEL,
623 			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
624 			__builtin_return_address(0));
625 
626 	if (ret) {
627 		struct vm_struct *vm = find_vm_area(addr);
628 		__memset(ret, KASAN_SHADOW_INIT, shadow_size);
629 		vm->flags |= VM_KASAN;
630 		kmemleak_ignore(ret);
631 
632 		if (vm->flags & VM_DEFER_KMEMLEAK)
633 			kmemleak_vmalloc(vm, size, gfp_mask);
634 
635 		return 0;
636 	}
637 
638 	return -ENOMEM;
639 }
640 
kasan_free_module_shadow(const struct vm_struct * vm)641 void kasan_free_module_shadow(const struct vm_struct *vm)
642 {
643 	if (IS_ENABLED(CONFIG_UML))
644 		return;
645 
646 	if (vm->flags & VM_KASAN)
647 		vfree(kasan_mem_to_shadow(vm->addr));
648 }
649 
650 #endif
651