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 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 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 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 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 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 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 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 102 103 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 123 124 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_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 } 148 EXPORT_SYMBOL_GPL(kasan_poison); 149 150 #ifdef CONFIG_KASAN_GENERIC 151 void kasan_poison_last_granule(const void *addr, size_t size) 152 { 153 if (!kasan_arch_is_ready()) 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 162 163 void 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 186 static 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 } 212 213 static 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 } 277 278 static int __init kasan_memhotplug_init(void) 279 { 280 hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI); 281 282 return 0; 283 } 284 285 core_initcall(kasan_memhotplug_init); 286 #endif 287 288 #ifdef CONFIG_KASAN_VMALLOC 289 290 void __init __weak kasan_populate_early_vm_area_shadow(void *start, 291 unsigned long size) 292 { 293 } 294 295 struct vmalloc_populate_data { 296 unsigned long start; 297 struct page **pages; 298 }; 299 300 static 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 } 326 327 static 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 } 338 339 static 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 } 356 357 static int __kasan_populate_vmalloc(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 if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) 381 flags = memalloc_nofs_save(); 382 else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0) 383 flags = memalloc_noio_save(); 384 385 ret = apply_to_page_range(&init_mm, start, nr_pages * PAGE_SIZE, 386 kasan_populate_vmalloc_pte, &data); 387 388 if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) 389 memalloc_nofs_restore(flags); 390 else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0) 391 memalloc_noio_restore(flags); 392 393 ___free_pages_bulk(data.pages, nr_pages); 394 if (ret) 395 break; 396 397 start += nr_pages * PAGE_SIZE; 398 nr_total -= nr_pages; 399 } 400 401 free_page((unsigned long)data.pages); 402 403 return ret; 404 } 405 406 int kasan_populate_vmalloc(unsigned long addr, unsigned long size, gfp_t gfp_mask) 407 { 408 unsigned long shadow_start, shadow_end; 409 int ret; 410 411 if (!kasan_arch_is_ready()) 412 return 0; 413 414 if (!is_vmalloc_or_module_addr((void *)addr)) 415 return 0; 416 417 shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr); 418 shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size); 419 420 /* 421 * User Mode Linux maps enough shadow memory for all of virtual memory 422 * at boot, so doesn't need to allocate more on vmalloc, just clear it. 423 * 424 * The remaining CONFIG_UML checks in this file exist for the same 425 * reason. 426 */ 427 if (IS_ENABLED(CONFIG_UML)) { 428 __memset((void *)shadow_start, KASAN_VMALLOC_INVALID, shadow_end - shadow_start); 429 return 0; 430 } 431 432 shadow_start = PAGE_ALIGN_DOWN(shadow_start); 433 shadow_end = PAGE_ALIGN(shadow_end); 434 435 ret = __kasan_populate_vmalloc(shadow_start, shadow_end, gfp_mask); 436 if (ret) 437 return ret; 438 439 flush_cache_vmap(shadow_start, shadow_end); 440 441 /* 442 * We need to be careful about inter-cpu effects here. Consider: 443 * 444 * CPU#0 CPU#1 445 * WRITE_ONCE(p, vmalloc(100)); while (x = READ_ONCE(p)) ; 446 * p[99] = 1; 447 * 448 * With compiler instrumentation, that ends up looking like this: 449 * 450 * CPU#0 CPU#1 451 * // vmalloc() allocates memory 452 * // let a = area->addr 453 * // we reach kasan_populate_vmalloc 454 * // and call kasan_unpoison: 455 * STORE shadow(a), unpoison_val 456 * ... 457 * STORE shadow(a+99), unpoison_val x = LOAD p 458 * // rest of vmalloc process <data dependency> 459 * STORE p, a LOAD shadow(x+99) 460 * 461 * If there is no barrier between the end of unpoisoning the shadow 462 * and the store of the result to p, the stores could be committed 463 * in a different order by CPU#0, and CPU#1 could erroneously observe 464 * poison in the shadow. 465 * 466 * We need some sort of barrier between the stores. 467 * 468 * In the vmalloc() case, this is provided by a smp_wmb() in 469 * clear_vm_uninitialized_flag(). In the per-cpu allocator and in 470 * get_vm_area() and friends, the caller gets shadow allocated but 471 * doesn't have any pages mapped into the virtual address space that 472 * has been reserved. Mapping those pages in will involve taking and 473 * releasing a page-table lock, which will provide the barrier. 474 */ 475 476 return 0; 477 } 478 479 static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr, 480 void *unused) 481 { 482 pte_t pte; 483 int none; 484 485 arch_leave_lazy_mmu_mode(); 486 487 spin_lock(&init_mm.page_table_lock); 488 pte = ptep_get(ptep); 489 none = pte_none(pte); 490 if (likely(!none)) 491 pte_clear(&init_mm, addr, ptep); 492 spin_unlock(&init_mm.page_table_lock); 493 494 if (likely(!none)) 495 __free_page(pfn_to_page(pte_pfn(pte))); 496 497 arch_enter_lazy_mmu_mode(); 498 499 return 0; 500 } 501 502 /* 503 * Release the backing for the vmalloc region [start, end), which 504 * lies within the free region [free_region_start, free_region_end). 505 * 506 * This can be run lazily, long after the region was freed. It runs 507 * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap 508 * infrastructure. 509 * 510 * How does this work? 511 * ------------------- 512 * 513 * We have a region that is page aligned, labeled as A. 514 * That might not map onto the shadow in a way that is page-aligned: 515 * 516 * start end 517 * v v 518 * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc 519 * -------- -------- -------- -------- -------- 520 * | | | | | 521 * | | | /-------/ | 522 * \-------\|/------/ |/---------------/ 523 * ||| || 524 * |??AAAAAA|AAAAAAAA|AA??????| < shadow 525 * (1) (2) (3) 526 * 527 * First we align the start upwards and the end downwards, so that the 528 * shadow of the region aligns with shadow page boundaries. In the 529 * example, this gives us the shadow page (2). This is the shadow entirely 530 * covered by this allocation. 531 * 532 * Then we have the tricky bits. We want to know if we can free the 533 * partially covered shadow pages - (1) and (3) in the example. For this, 534 * we are given the start and end of the free region that contains this 535 * allocation. Extending our previous example, we could have: 536 * 537 * free_region_start free_region_end 538 * | start end | 539 * v v v v 540 * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc 541 * -------- -------- -------- -------- -------- 542 * | | | | | 543 * | | | /-------/ | 544 * \-------\|/------/ |/---------------/ 545 * ||| || 546 * |FFAAAAAA|AAAAAAAA|AAF?????| < shadow 547 * (1) (2) (3) 548 * 549 * Once again, we align the start of the free region up, and the end of 550 * the free region down so that the shadow is page aligned. So we can free 551 * page (1) - we know no allocation currently uses anything in that page, 552 * because all of it is in the vmalloc free region. But we cannot free 553 * page (3), because we can't be sure that the rest of it is unused. 554 * 555 * We only consider pages that contain part of the original region for 556 * freeing: we don't try to free other pages from the free region or we'd 557 * end up trying to free huge chunks of virtual address space. 558 * 559 * Concurrency 560 * ----------- 561 * 562 * How do we know that we're not freeing a page that is simultaneously 563 * being used for a fresh allocation in kasan_populate_vmalloc(_pte)? 564 * 565 * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running 566 * at the same time. While we run under free_vmap_area_lock, the population 567 * code does not. 568 * 569 * free_vmap_area_lock instead operates to ensure that the larger range 570 * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and 571 * the per-cpu region-finding algorithm both run under free_vmap_area_lock, 572 * no space identified as free will become used while we are running. This 573 * means that so long as we are careful with alignment and only free shadow 574 * pages entirely covered by the free region, we will not run in to any 575 * trouble - any simultaneous allocations will be for disjoint regions. 576 */ 577 void kasan_release_vmalloc(unsigned long start, unsigned long end, 578 unsigned long free_region_start, 579 unsigned long free_region_end, 580 unsigned long flags) 581 { 582 void *shadow_start, *shadow_end; 583 unsigned long region_start, region_end; 584 unsigned long size; 585 586 if (!kasan_arch_is_ready()) 587 return; 588 589 region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE); 590 region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE); 591 592 free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE); 593 594 if (start != region_start && 595 free_region_start < region_start) 596 region_start -= KASAN_MEMORY_PER_SHADOW_PAGE; 597 598 free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE); 599 600 if (end != region_end && 601 free_region_end > region_end) 602 region_end += KASAN_MEMORY_PER_SHADOW_PAGE; 603 604 shadow_start = kasan_mem_to_shadow((void *)region_start); 605 shadow_end = kasan_mem_to_shadow((void *)region_end); 606 607 if (shadow_end > shadow_start) { 608 size = shadow_end - shadow_start; 609 if (IS_ENABLED(CONFIG_UML)) { 610 __memset(shadow_start, KASAN_SHADOW_INIT, shadow_end - shadow_start); 611 return; 612 } 613 614 615 if (flags & KASAN_VMALLOC_PAGE_RANGE) 616 apply_to_existing_page_range(&init_mm, 617 (unsigned long)shadow_start, 618 size, kasan_depopulate_vmalloc_pte, 619 NULL); 620 621 if (flags & KASAN_VMALLOC_TLB_FLUSH) 622 flush_tlb_kernel_range((unsigned long)shadow_start, 623 (unsigned long)shadow_end); 624 } 625 } 626 627 void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, 628 kasan_vmalloc_flags_t flags) 629 { 630 /* 631 * Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC 632 * mappings, so the KASAN_VMALLOC_VM_ALLOC flag is ignored. 633 * Software KASAN modes can't optimize zeroing memory by combining it 634 * with setting memory tags, so the KASAN_VMALLOC_INIT flag is ignored. 635 */ 636 637 if (!kasan_arch_is_ready()) 638 return (void *)start; 639 640 if (!is_vmalloc_or_module_addr(start)) 641 return (void *)start; 642 643 /* 644 * Don't tag executable memory with the tag-based mode. 645 * The kernel doesn't tolerate having the PC register tagged. 646 */ 647 if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) && 648 !(flags & KASAN_VMALLOC_PROT_NORMAL)) 649 return (void *)start; 650 651 start = set_tag(start, kasan_random_tag()); 652 kasan_unpoison(start, size, false); 653 return (void *)start; 654 } 655 656 /* 657 * Poison the shadow for a vmalloc region. Called as part of the 658 * freeing process at the time the region is freed. 659 */ 660 void __kasan_poison_vmalloc(const void *start, unsigned long size) 661 { 662 if (!kasan_arch_is_ready()) 663 return; 664 665 if (!is_vmalloc_or_module_addr(start)) 666 return; 667 668 size = round_up(size, KASAN_GRANULE_SIZE); 669 kasan_poison(start, size, KASAN_VMALLOC_INVALID, false); 670 } 671 672 #else /* CONFIG_KASAN_VMALLOC */ 673 674 int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask) 675 { 676 void *ret; 677 size_t scaled_size; 678 size_t shadow_size; 679 unsigned long shadow_start; 680 681 shadow_start = (unsigned long)kasan_mem_to_shadow(addr); 682 scaled_size = (size + KASAN_GRANULE_SIZE - 1) >> 683 KASAN_SHADOW_SCALE_SHIFT; 684 shadow_size = round_up(scaled_size, PAGE_SIZE); 685 686 if (WARN_ON(!PAGE_ALIGNED(shadow_start))) 687 return -EINVAL; 688 689 if (IS_ENABLED(CONFIG_UML)) { 690 __memset((void *)shadow_start, KASAN_SHADOW_INIT, shadow_size); 691 return 0; 692 } 693 694 ret = __vmalloc_node_range(shadow_size, 1, shadow_start, 695 shadow_start + shadow_size, 696 GFP_KERNEL, 697 PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE, 698 __builtin_return_address(0)); 699 700 if (ret) { 701 struct vm_struct *vm = find_vm_area(addr); 702 __memset(ret, KASAN_SHADOW_INIT, shadow_size); 703 vm->flags |= VM_KASAN; 704 kmemleak_ignore(ret); 705 706 if (vm->flags & VM_DEFER_KMEMLEAK) 707 kmemleak_vmalloc(vm, size, gfp_mask); 708 709 return 0; 710 } 711 712 return -ENOMEM; 713 } 714 715 void kasan_free_module_shadow(const struct vm_struct *vm) 716 { 717 if (IS_ENABLED(CONFIG_UML)) 718 return; 719 720 if (vm->flags & VM_KASAN) 721 vfree(kasan_mem_to_shadow(vm->addr)); 722 } 723 724 #endif 725