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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * mm/mprotect.c | |
4 | * | |
5 | * (C) Copyright 1994 Linus Torvalds | |
6 | * (C) Copyright 2002 Christoph Hellwig | |
7 | * | |
8 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> | |
9 | * (C) Copyright 2002 Red Hat Inc, All Rights Reserved | |
10 | */ | |
11 | ||
12 | #include <linux/pagewalk.h> | |
13 | #include <linux/hugetlb.h> | |
14 | #include <linux/shm.h> | |
15 | #include <linux/mman.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/highmem.h> | |
18 | #include <linux/security.h> | |
19 | #include <linux/mempolicy.h> | |
20 | #include <linux/personality.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/swap.h> | |
23 | #include <linux/swapops.h> | |
24 | #include <linux/mmu_notifier.h> | |
25 | #include <linux/migrate.h> | |
26 | #include <linux/perf_event.h> | |
27 | #include <linux/pkeys.h> | |
28 | #include <linux/ksm.h> | |
29 | #include <linux/uaccess.h> | |
30 | #include <linux/mm_inline.h> | |
31 | #include <asm/pgtable.h> | |
32 | #include <asm/cacheflush.h> | |
33 | #include <asm/mmu_context.h> | |
34 | #include <asm/tlbflush.h> | |
35 | ||
36 | #include "internal.h" | |
37 | ||
38 | static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
39 | unsigned long addr, unsigned long end, pgprot_t newprot, | |
40 | int dirty_accountable, int prot_numa) | |
41 | { | |
42 | pte_t *pte, oldpte; | |
43 | spinlock_t *ptl; | |
44 | unsigned long pages = 0; | |
45 | int target_node = NUMA_NO_NODE; | |
46 | ||
47 | /* | |
48 | * Can be called with only the mmap_sem for reading by | |
49 | * prot_numa so we must check the pmd isn't constantly | |
50 | * changing from under us from pmd_none to pmd_trans_huge | |
51 | * and/or the other way around. | |
52 | */ | |
53 | if (pmd_trans_unstable(pmd)) | |
54 | return 0; | |
55 | ||
56 | /* | |
57 | * The pmd points to a regular pte so the pmd can't change | |
58 | * from under us even if the mmap_sem is only hold for | |
59 | * reading. | |
60 | */ | |
61 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
62 | ||
63 | /* Get target node for single threaded private VMAs */ | |
64 | if (prot_numa && !(vma->vm_flags & VM_SHARED) && | |
65 | atomic_read(&vma->vm_mm->mm_users) == 1) | |
66 | target_node = numa_node_id(); | |
67 | ||
68 | flush_tlb_batched_pending(vma->vm_mm); | |
69 | arch_enter_lazy_mmu_mode(); | |
70 | do { | |
71 | oldpte = *pte; | |
72 | if (pte_present(oldpte)) { | |
73 | pte_t ptent; | |
74 | bool preserve_write = prot_numa && pte_write(oldpte); | |
75 | ||
76 | /* | |
77 | * Avoid trapping faults against the zero or KSM | |
78 | * pages. See similar comment in change_huge_pmd. | |
79 | */ | |
80 | if (prot_numa) { | |
81 | struct page *page; | |
82 | ||
83 | /* Avoid TLB flush if possible */ | |
84 | if (pte_protnone(oldpte)) | |
85 | continue; | |
86 | ||
87 | page = vm_normal_page(vma, addr, oldpte); | |
88 | if (!page || PageKsm(page)) | |
89 | continue; | |
90 | ||
91 | /* Also skip shared copy-on-write pages */ | |
92 | if (is_cow_mapping(vma->vm_flags) && | |
93 | page_mapcount(page) != 1) | |
94 | continue; | |
95 | ||
96 | /* | |
97 | * While migration can move some dirty pages, | |
98 | * it cannot move them all from MIGRATE_ASYNC | |
99 | * context. | |
100 | */ | |
101 | if (page_is_file_lru(page) && PageDirty(page)) | |
102 | continue; | |
103 | ||
104 | /* | |
105 | * Don't mess with PTEs if page is already on the node | |
106 | * a single-threaded process is running on. | |
107 | */ | |
108 | if (target_node == page_to_nid(page)) | |
109 | continue; | |
110 | } | |
111 | ||
112 | oldpte = ptep_modify_prot_start(vma, addr, pte); | |
113 | ptent = pte_modify(oldpte, newprot); | |
114 | if (preserve_write) | |
115 | ptent = pte_mk_savedwrite(ptent); | |
116 | ||
117 | /* Avoid taking write faults for known dirty pages */ | |
118 | if (dirty_accountable && pte_dirty(ptent) && | |
119 | (pte_soft_dirty(ptent) || | |
120 | !(vma->vm_flags & VM_SOFTDIRTY))) { | |
121 | ptent = pte_mkwrite(ptent); | |
122 | } | |
123 | ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); | |
124 | pages++; | |
125 | } else if (IS_ENABLED(CONFIG_MIGRATION)) { | |
126 | swp_entry_t entry = pte_to_swp_entry(oldpte); | |
127 | ||
128 | if (is_write_migration_entry(entry)) { | |
129 | pte_t newpte; | |
130 | /* | |
131 | * A protection check is difficult so | |
132 | * just be safe and disable write | |
133 | */ | |
134 | make_migration_entry_read(&entry); | |
135 | newpte = swp_entry_to_pte(entry); | |
136 | if (pte_swp_soft_dirty(oldpte)) | |
137 | newpte = pte_swp_mksoft_dirty(newpte); | |
138 | set_pte_at(vma->vm_mm, addr, pte, newpte); | |
139 | ||
140 | pages++; | |
141 | } | |
142 | ||
143 | if (is_write_device_private_entry(entry)) { | |
144 | pte_t newpte; | |
145 | ||
146 | /* | |
147 | * We do not preserve soft-dirtiness. See | |
148 | * copy_one_pte() for explanation. | |
149 | */ | |
150 | make_device_private_entry_read(&entry); | |
151 | newpte = swp_entry_to_pte(entry); | |
152 | set_pte_at(vma->vm_mm, addr, pte, newpte); | |
153 | ||
154 | pages++; | |
155 | } | |
156 | } | |
157 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
158 | arch_leave_lazy_mmu_mode(); | |
159 | pte_unmap_unlock(pte - 1, ptl); | |
160 | ||
161 | return pages; | |
162 | } | |
163 | ||
164 | /* | |
165 | * Used when setting automatic NUMA hinting protection where it is | |
166 | * critical that a numa hinting PMD is not confused with a bad PMD. | |
167 | */ | |
168 | static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) | |
169 | { | |
170 | pmd_t pmdval = pmd_read_atomic(pmd); | |
171 | ||
172 | /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */ | |
173 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
174 | barrier(); | |
175 | #endif | |
176 | ||
177 | if (pmd_none(pmdval)) | |
178 | return 1; | |
179 | if (pmd_trans_huge(pmdval)) | |
180 | return 0; | |
181 | if (unlikely(pmd_bad(pmdval))) { | |
182 | pmd_clear_bad(pmd); | |
183 | return 1; | |
184 | } | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static inline unsigned long change_pmd_range(struct vm_area_struct *vma, | |
190 | pud_t *pud, unsigned long addr, unsigned long end, | |
191 | pgprot_t newprot, int dirty_accountable, int prot_numa) | |
192 | { | |
193 | pmd_t *pmd; | |
194 | unsigned long next; | |
195 | unsigned long pages = 0; | |
196 | unsigned long nr_huge_updates = 0; | |
197 | struct mmu_notifier_range range; | |
198 | ||
199 | range.start = 0; | |
200 | ||
201 | pmd = pmd_offset(pud, addr); | |
202 | do { | |
203 | unsigned long this_pages; | |
204 | ||
205 | next = pmd_addr_end(addr, end); | |
206 | ||
207 | /* | |
208 | * Automatic NUMA balancing walks the tables with mmap_sem | |
209 | * held for read. It's possible a parallel update to occur | |
210 | * between pmd_trans_huge() and a pmd_none_or_clear_bad() | |
211 | * check leading to a false positive and clearing. | |
212 | * Hence, it's necessary to atomically read the PMD value | |
213 | * for all the checks. | |
214 | */ | |
215 | if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) && | |
216 | pmd_none_or_clear_bad_unless_trans_huge(pmd)) | |
217 | goto next; | |
218 | ||
219 | /* invoke the mmu notifier if the pmd is populated */ | |
220 | if (!range.start) { | |
221 | mmu_notifier_range_init(&range, | |
222 | MMU_NOTIFY_PROTECTION_VMA, 0, | |
223 | vma, vma->vm_mm, addr, end); | |
224 | mmu_notifier_invalidate_range_start(&range); | |
225 | } | |
226 | ||
227 | if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { | |
228 | if (next - addr != HPAGE_PMD_SIZE) { | |
229 | __split_huge_pmd(vma, pmd, addr, false, NULL); | |
230 | } else { | |
231 | int nr_ptes = change_huge_pmd(vma, pmd, addr, | |
232 | newprot, prot_numa); | |
233 | ||
234 | if (nr_ptes) { | |
235 | if (nr_ptes == HPAGE_PMD_NR) { | |
236 | pages += HPAGE_PMD_NR; | |
237 | nr_huge_updates++; | |
238 | } | |
239 | ||
240 | /* huge pmd was handled */ | |
241 | goto next; | |
242 | } | |
243 | } | |
244 | /* fall through, the trans huge pmd just split */ | |
245 | } | |
246 | this_pages = change_pte_range(vma, pmd, addr, next, newprot, | |
247 | dirty_accountable, prot_numa); | |
248 | pages += this_pages; | |
249 | next: | |
250 | cond_resched(); | |
251 | } while (pmd++, addr = next, addr != end); | |
252 | ||
253 | if (range.start) | |
254 | mmu_notifier_invalidate_range_end(&range); | |
255 | ||
256 | if (nr_huge_updates) | |
257 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
258 | return pages; | |
259 | } | |
260 | ||
261 | static inline unsigned long change_pud_range(struct vm_area_struct *vma, | |
262 | p4d_t *p4d, unsigned long addr, unsigned long end, | |
263 | pgprot_t newprot, int dirty_accountable, int prot_numa) | |
264 | { | |
265 | pud_t *pud; | |
266 | unsigned long next; | |
267 | unsigned long pages = 0; | |
268 | ||
269 | pud = pud_offset(p4d, addr); | |
270 | do { | |
271 | next = pud_addr_end(addr, end); | |
272 | if (pud_none_or_clear_bad(pud)) | |
273 | continue; | |
274 | pages += change_pmd_range(vma, pud, addr, next, newprot, | |
275 | dirty_accountable, prot_numa); | |
276 | } while (pud++, addr = next, addr != end); | |
277 | ||
278 | return pages; | |
279 | } | |
280 | ||
281 | static inline unsigned long change_p4d_range(struct vm_area_struct *vma, | |
282 | pgd_t *pgd, unsigned long addr, unsigned long end, | |
283 | pgprot_t newprot, int dirty_accountable, int prot_numa) | |
284 | { | |
285 | p4d_t *p4d; | |
286 | unsigned long next; | |
287 | unsigned long pages = 0; | |
288 | ||
289 | p4d = p4d_offset(pgd, addr); | |
290 | do { | |
291 | next = p4d_addr_end(addr, end); | |
292 | if (p4d_none_or_clear_bad(p4d)) | |
293 | continue; | |
294 | pages += change_pud_range(vma, p4d, addr, next, newprot, | |
295 | dirty_accountable, prot_numa); | |
296 | } while (p4d++, addr = next, addr != end); | |
297 | ||
298 | return pages; | |
299 | } | |
300 | ||
301 | static unsigned long change_protection_range(struct vm_area_struct *vma, | |
302 | unsigned long addr, unsigned long end, pgprot_t newprot, | |
303 | int dirty_accountable, int prot_numa) | |
304 | { | |
305 | struct mm_struct *mm = vma->vm_mm; | |
306 | pgd_t *pgd; | |
307 | unsigned long next; | |
308 | unsigned long start = addr; | |
309 | unsigned long pages = 0; | |
310 | ||
311 | BUG_ON(addr >= end); | |
312 | pgd = pgd_offset(mm, addr); | |
313 | flush_cache_range(vma, addr, end); | |
314 | inc_tlb_flush_pending(mm); | |
315 | do { | |
316 | next = pgd_addr_end(addr, end); | |
317 | if (pgd_none_or_clear_bad(pgd)) | |
318 | continue; | |
319 | pages += change_p4d_range(vma, pgd, addr, next, newprot, | |
320 | dirty_accountable, prot_numa); | |
321 | } while (pgd++, addr = next, addr != end); | |
322 | ||
323 | /* Only flush the TLB if we actually modified any entries: */ | |
324 | if (pages) | |
325 | flush_tlb_range(vma, start, end); | |
326 | dec_tlb_flush_pending(mm); | |
327 | ||
328 | return pages; | |
329 | } | |
330 | ||
331 | unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, | |
332 | unsigned long end, pgprot_t newprot, | |
333 | int dirty_accountable, int prot_numa) | |
334 | { | |
335 | unsigned long pages; | |
336 | ||
337 | if (is_vm_hugetlb_page(vma)) | |
338 | pages = hugetlb_change_protection(vma, start, end, newprot); | |
339 | else | |
340 | pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa); | |
341 | ||
342 | return pages; | |
343 | } | |
344 | ||
345 | static int prot_none_pte_entry(pte_t *pte, unsigned long addr, | |
346 | unsigned long next, struct mm_walk *walk) | |
347 | { | |
348 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
349 | 0 : -EACCES; | |
350 | } | |
351 | ||
352 | static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, | |
353 | unsigned long addr, unsigned long next, | |
354 | struct mm_walk *walk) | |
355 | { | |
356 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
357 | 0 : -EACCES; | |
358 | } | |
359 | ||
360 | static int prot_none_test(unsigned long addr, unsigned long next, | |
361 | struct mm_walk *walk) | |
362 | { | |
363 | return 0; | |
364 | } | |
365 | ||
366 | static const struct mm_walk_ops prot_none_walk_ops = { | |
367 | .pte_entry = prot_none_pte_entry, | |
368 | .hugetlb_entry = prot_none_hugetlb_entry, | |
369 | .test_walk = prot_none_test, | |
370 | }; | |
371 | ||
372 | int | |
373 | mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, | |
374 | unsigned long start, unsigned long end, unsigned long newflags) | |
375 | { | |
376 | struct mm_struct *mm = vma->vm_mm; | |
377 | unsigned long oldflags = vma->vm_flags; | |
378 | long nrpages = (end - start) >> PAGE_SHIFT; | |
379 | unsigned long charged = 0; | |
380 | pgoff_t pgoff; | |
381 | int error; | |
382 | int dirty_accountable = 0; | |
383 | ||
384 | if (newflags == oldflags) { | |
385 | *pprev = vma; | |
386 | return 0; | |
387 | } | |
388 | ||
389 | /* | |
390 | * Do PROT_NONE PFN permission checks here when we can still | |
391 | * bail out without undoing a lot of state. This is a rather | |
392 | * uncommon case, so doesn't need to be very optimized. | |
393 | */ | |
394 | if (arch_has_pfn_modify_check() && | |
395 | (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && | |
396 | (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) { | |
397 | pgprot_t new_pgprot = vm_get_page_prot(newflags); | |
398 | ||
399 | error = walk_page_range(current->mm, start, end, | |
400 | &prot_none_walk_ops, &new_pgprot); | |
401 | if (error) | |
402 | return error; | |
403 | } | |
404 | ||
405 | /* | |
406 | * If we make a private mapping writable we increase our commit; | |
407 | * but (without finer accounting) cannot reduce our commit if we | |
408 | * make it unwritable again. hugetlb mapping were accounted for | |
409 | * even if read-only so there is no need to account for them here | |
410 | */ | |
411 | if (newflags & VM_WRITE) { | |
412 | /* Check space limits when area turns into data. */ | |
413 | if (!may_expand_vm(mm, newflags, nrpages) && | |
414 | may_expand_vm(mm, oldflags, nrpages)) | |
415 | return -ENOMEM; | |
416 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| | |
417 | VM_SHARED|VM_NORESERVE))) { | |
418 | charged = nrpages; | |
419 | if (security_vm_enough_memory_mm(mm, charged)) | |
420 | return -ENOMEM; | |
421 | newflags |= VM_ACCOUNT; | |
422 | } | |
423 | } | |
424 | ||
425 | /* | |
426 | * First try to merge with previous and/or next vma. | |
427 | */ | |
428 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
429 | *pprev = vma_merge(mm, *pprev, start, end, newflags, | |
430 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), | |
431 | vma->vm_userfaultfd_ctx); | |
432 | if (*pprev) { | |
433 | vma = *pprev; | |
434 | VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY); | |
435 | goto success; | |
436 | } | |
437 | ||
438 | *pprev = vma; | |
439 | ||
440 | if (start != vma->vm_start) { | |
441 | error = split_vma(mm, vma, start, 1); | |
442 | if (error) | |
443 | goto fail; | |
444 | } | |
445 | ||
446 | if (end != vma->vm_end) { | |
447 | error = split_vma(mm, vma, end, 0); | |
448 | if (error) | |
449 | goto fail; | |
450 | } | |
451 | ||
452 | success: | |
453 | /* | |
454 | * vm_flags and vm_page_prot are protected by the mmap_sem | |
455 | * held in write mode. | |
456 | */ | |
457 | vma->vm_flags = newflags; | |
458 | dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot); | |
459 | vma_set_page_prot(vma); | |
460 | ||
461 | change_protection(vma, start, end, vma->vm_page_prot, | |
462 | dirty_accountable, 0); | |
463 | ||
464 | /* | |
465 | * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major | |
466 | * fault on access. | |
467 | */ | |
468 | if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED && | |
469 | (newflags & VM_WRITE)) { | |
470 | populate_vma_page_range(vma, start, end, NULL); | |
471 | } | |
472 | ||
473 | vm_stat_account(mm, oldflags, -nrpages); | |
474 | vm_stat_account(mm, newflags, nrpages); | |
475 | perf_event_mmap(vma); | |
476 | return 0; | |
477 | ||
478 | fail: | |
479 | vm_unacct_memory(charged); | |
480 | return error; | |
481 | } | |
482 | ||
483 | /* | |
484 | * pkey==-1 when doing a legacy mprotect() | |
485 | */ | |
486 | static int do_mprotect_pkey(unsigned long start, size_t len, | |
487 | unsigned long prot, int pkey) | |
488 | { | |
489 | unsigned long nstart, end, tmp, reqprot; | |
490 | struct vm_area_struct *vma, *prev; | |
491 | int error = -EINVAL; | |
492 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); | |
493 | const bool rier = (current->personality & READ_IMPLIES_EXEC) && | |
494 | (prot & PROT_READ); | |
495 | ||
496 | start = untagged_addr(start); | |
497 | ||
498 | prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); | |
499 | if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ | |
500 | return -EINVAL; | |
501 | ||
502 | if (start & ~PAGE_MASK) | |
503 | return -EINVAL; | |
504 | if (!len) | |
505 | return 0; | |
506 | len = PAGE_ALIGN(len); | |
507 | end = start + len; | |
508 | if (end <= start) | |
509 | return -ENOMEM; | |
510 | if (!arch_validate_prot(prot, start)) | |
511 | return -EINVAL; | |
512 | ||
513 | reqprot = prot; | |
514 | ||
515 | if (down_write_killable(¤t->mm->mmap_sem)) | |
516 | return -EINTR; | |
517 | ||
518 | /* | |
519 | * If userspace did not allocate the pkey, do not let | |
520 | * them use it here. | |
521 | */ | |
522 | error = -EINVAL; | |
523 | if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey)) | |
524 | goto out; | |
525 | ||
526 | vma = find_vma(current->mm, start); | |
527 | error = -ENOMEM; | |
528 | if (!vma) | |
529 | goto out; | |
530 | prev = vma->vm_prev; | |
531 | if (unlikely(grows & PROT_GROWSDOWN)) { | |
532 | if (vma->vm_start >= end) | |
533 | goto out; | |
534 | start = vma->vm_start; | |
535 | error = -EINVAL; | |
536 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
537 | goto out; | |
538 | } else { | |
539 | if (vma->vm_start > start) | |
540 | goto out; | |
541 | if (unlikely(grows & PROT_GROWSUP)) { | |
542 | end = vma->vm_end; | |
543 | error = -EINVAL; | |
544 | if (!(vma->vm_flags & VM_GROWSUP)) | |
545 | goto out; | |
546 | } | |
547 | } | |
548 | if (start > vma->vm_start) | |
549 | prev = vma; | |
550 | ||
551 | for (nstart = start ; ; ) { | |
552 | unsigned long mask_off_old_flags; | |
553 | unsigned long newflags; | |
554 | int new_vma_pkey; | |
555 | ||
556 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ | |
557 | ||
558 | /* Does the application expect PROT_READ to imply PROT_EXEC */ | |
559 | if (rier && (vma->vm_flags & VM_MAYEXEC)) | |
560 | prot |= PROT_EXEC; | |
561 | ||
562 | /* | |
563 | * Each mprotect() call explicitly passes r/w/x permissions. | |
564 | * If a permission is not passed to mprotect(), it must be | |
565 | * cleared from the VMA. | |
566 | */ | |
567 | mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC | | |
568 | VM_FLAGS_CLEAR; | |
569 | ||
570 | new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); | |
571 | newflags = calc_vm_prot_bits(prot, new_vma_pkey); | |
572 | newflags |= (vma->vm_flags & ~mask_off_old_flags); | |
573 | ||
574 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ | |
575 | if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) { | |
576 | error = -EACCES; | |
577 | goto out; | |
578 | } | |
579 | ||
580 | error = security_file_mprotect(vma, reqprot, prot); | |
581 | if (error) | |
582 | goto out; | |
583 | ||
584 | tmp = vma->vm_end; | |
585 | if (tmp > end) | |
586 | tmp = end; | |
587 | error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); | |
588 | if (error) | |
589 | goto out; | |
590 | nstart = tmp; | |
591 | ||
592 | if (nstart < prev->vm_end) | |
593 | nstart = prev->vm_end; | |
594 | if (nstart >= end) | |
595 | goto out; | |
596 | ||
597 | vma = prev->vm_next; | |
598 | if (!vma || vma->vm_start != nstart) { | |
599 | error = -ENOMEM; | |
600 | goto out; | |
601 | } | |
602 | prot = reqprot; | |
603 | } | |
604 | out: | |
605 | up_write(¤t->mm->mmap_sem); | |
606 | return error; | |
607 | } | |
608 | ||
609 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, | |
610 | unsigned long, prot) | |
611 | { | |
612 | return do_mprotect_pkey(start, len, prot, -1); | |
613 | } | |
614 | ||
615 | #ifdef CONFIG_ARCH_HAS_PKEYS | |
616 | ||
617 | SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, | |
618 | unsigned long, prot, int, pkey) | |
619 | { | |
620 | return do_mprotect_pkey(start, len, prot, pkey); | |
621 | } | |
622 | ||
623 | SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) | |
624 | { | |
625 | int pkey; | |
626 | int ret; | |
627 | ||
628 | /* No flags supported yet. */ | |
629 | if (flags) | |
630 | return -EINVAL; | |
631 | /* check for unsupported init values */ | |
632 | if (init_val & ~PKEY_ACCESS_MASK) | |
633 | return -EINVAL; | |
634 | ||
635 | down_write(¤t->mm->mmap_sem); | |
636 | pkey = mm_pkey_alloc(current->mm); | |
637 | ||
638 | ret = -ENOSPC; | |
639 | if (pkey == -1) | |
640 | goto out; | |
641 | ||
642 | ret = arch_set_user_pkey_access(current, pkey, init_val); | |
643 | if (ret) { | |
644 | mm_pkey_free(current->mm, pkey); | |
645 | goto out; | |
646 | } | |
647 | ret = pkey; | |
648 | out: | |
649 | up_write(¤t->mm->mmap_sem); | |
650 | return ret; | |
651 | } | |
652 | ||
653 | SYSCALL_DEFINE1(pkey_free, int, pkey) | |
654 | { | |
655 | int ret; | |
656 | ||
657 | down_write(¤t->mm->mmap_sem); | |
658 | ret = mm_pkey_free(current->mm, pkey); | |
659 | up_write(¤t->mm->mmap_sem); | |
660 | ||
661 | /* | |
662 | * We could provie warnings or errors if any VMA still | |
663 | * has the pkey set here. | |
664 | */ | |
665 | return ret; | |
666 | } | |
667 | ||
668 | #endif /* CONFIG_ARCH_HAS_PKEYS */ |