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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 <linux/pgtable.h>
32 #include <asm/cacheflush.h>
33 #include <asm/mmu_context.h>
34 #include <asm/tlbflush.h>
35 
36 #include "internal.h"
37 
change_pte_range(struct vm_area_struct * vma,pmd_t * pmd,unsigned long addr,unsigned long end,pgprot_t newprot,unsigned long cp_flags)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 		unsigned long cp_flags)
41 {
42 	pte_t *pte, oldpte;
43 	spinlock_t *ptl;
44 	unsigned long pages = 0;
45 	int target_node = NUMA_NO_NODE;
46 	bool dirty_accountable = cp_flags & MM_CP_DIRTY_ACCT;
47 	bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
48 	bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
49 	bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
50 
51 	/*
52 	 * Can be called with only the mmap_lock for reading by
53 	 * prot_numa so we must check the pmd isn't constantly
54 	 * changing from under us from pmd_none to pmd_trans_huge
55 	 * and/or the other way around.
56 	 */
57 	if (pmd_trans_unstable(pmd))
58 		return 0;
59 
60 	/*
61 	 * The pmd points to a regular pte so the pmd can't change
62 	 * from under us even if the mmap_lock is only hold for
63 	 * reading.
64 	 */
65 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
66 
67 	/* Get target node for single threaded private VMAs */
68 	if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
69 	    atomic_read(&vma->vm_mm->mm_users) == 1)
70 		target_node = numa_node_id();
71 
72 	flush_tlb_batched_pending(vma->vm_mm);
73 	arch_enter_lazy_mmu_mode();
74 	do {
75 		oldpte = *pte;
76 		if (pte_present(oldpte)) {
77 			pte_t ptent;
78 			bool preserve_write = prot_numa && pte_write(oldpte);
79 
80 			/*
81 			 * Avoid trapping faults against the zero or KSM
82 			 * pages. See similar comment in change_huge_pmd.
83 			 */
84 			if (prot_numa) {
85 				struct page *page;
86 
87 				/* Avoid TLB flush if possible */
88 				if (pte_protnone(oldpte))
89 					continue;
90 
91 				page = vm_normal_page(vma, addr, oldpte);
92 				if (!page || PageKsm(page))
93 					continue;
94 
95 				/* Also skip shared copy-on-write pages */
96 				if (is_cow_mapping(vma->vm_flags) &&
97 				    page_count(page) != 1)
98 					continue;
99 
100 				/*
101 				 * While migration can move some dirty pages,
102 				 * it cannot move them all from MIGRATE_ASYNC
103 				 * context.
104 				 */
105 				if (page_is_file_lru(page) && PageDirty(page))
106 					continue;
107 
108 				/*
109 				 * Don't mess with PTEs if page is already on the node
110 				 * a single-threaded process is running on.
111 				 */
112 				if (target_node == page_to_nid(page))
113 					continue;
114 			}
115 
116 			oldpte = ptep_modify_prot_start(vma, addr, pte);
117 			ptent = pte_modify(oldpte, newprot);
118 			if (preserve_write)
119 				ptent = pte_mk_savedwrite(ptent);
120 
121 			if (uffd_wp) {
122 				ptent = pte_wrprotect(ptent);
123 				ptent = pte_mkuffd_wp(ptent);
124 			} else if (uffd_wp_resolve) {
125 				/*
126 				 * Leave the write bit to be handled
127 				 * by PF interrupt handler, then
128 				 * things like COW could be properly
129 				 * handled.
130 				 */
131 				ptent = pte_clear_uffd_wp(ptent);
132 			}
133 
134 			/* Avoid taking write faults for known dirty pages */
135 			if (dirty_accountable && pte_dirty(ptent) &&
136 					(pte_soft_dirty(ptent) ||
137 					 !(vma->vm_flags & VM_SOFTDIRTY))) {
138 				ptent = pte_mkwrite(ptent);
139 			}
140 			ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
141 			pages++;
142 		} else if (is_swap_pte(oldpte)) {
143 			swp_entry_t entry = pte_to_swp_entry(oldpte);
144 			pte_t newpte;
145 
146 			if (is_write_migration_entry(entry)) {
147 				/*
148 				 * A protection check is difficult so
149 				 * just be safe and disable write
150 				 */
151 				make_migration_entry_read(&entry);
152 				newpte = swp_entry_to_pte(entry);
153 				if (pte_swp_soft_dirty(oldpte))
154 					newpte = pte_swp_mksoft_dirty(newpte);
155 				if (pte_swp_uffd_wp(oldpte))
156 					newpte = pte_swp_mkuffd_wp(newpte);
157 			} else if (is_write_device_private_entry(entry)) {
158 				/*
159 				 * We do not preserve soft-dirtiness. See
160 				 * copy_one_pte() for explanation.
161 				 */
162 				make_device_private_entry_read(&entry);
163 				newpte = swp_entry_to_pte(entry);
164 				if (pte_swp_uffd_wp(oldpte))
165 					newpte = pte_swp_mkuffd_wp(newpte);
166 			} else {
167 				newpte = oldpte;
168 			}
169 
170 			if (uffd_wp)
171 				newpte = pte_swp_mkuffd_wp(newpte);
172 			else if (uffd_wp_resolve)
173 				newpte = pte_swp_clear_uffd_wp(newpte);
174 
175 			if (!pte_same(oldpte, newpte)) {
176 				set_pte_at(vma->vm_mm, addr, pte, newpte);
177 				pages++;
178 			}
179 		}
180 	} while (pte++, addr += PAGE_SIZE, addr != end);
181 	arch_leave_lazy_mmu_mode();
182 	pte_unmap_unlock(pte - 1, ptl);
183 
184 	return pages;
185 }
186 
187 /*
188  * Used when setting automatic NUMA hinting protection where it is
189  * critical that a numa hinting PMD is not confused with a bad PMD.
190  */
pmd_none_or_clear_bad_unless_trans_huge(pmd_t * pmd)191 static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd)
192 {
193 	pmd_t pmdval = pmd_read_atomic(pmd);
194 
195 	/* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */
196 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
197 	barrier();
198 #endif
199 
200 	if (pmd_none(pmdval))
201 		return 1;
202 	if (pmd_trans_huge(pmdval))
203 		return 0;
204 	if (unlikely(pmd_bad(pmdval))) {
205 		pmd_clear_bad(pmd);
206 		return 1;
207 	}
208 
209 	return 0;
210 }
211 
change_pmd_range(struct vm_area_struct * vma,pud_t * pud,unsigned long addr,unsigned long end,pgprot_t newprot,unsigned long cp_flags)212 static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
213 		pud_t *pud, unsigned long addr, unsigned long end,
214 		pgprot_t newprot, unsigned long cp_flags)
215 {
216 	pmd_t *pmd;
217 	unsigned long next;
218 	unsigned long pages = 0;
219 	unsigned long nr_huge_updates = 0;
220 	struct mmu_notifier_range range;
221 
222 	range.start = 0;
223 
224 	pmd = pmd_offset(pud, addr);
225 	do {
226 		unsigned long this_pages;
227 
228 		next = pmd_addr_end(addr, end);
229 
230 		/*
231 		 * Automatic NUMA balancing walks the tables with mmap_lock
232 		 * held for read. It's possible a parallel update to occur
233 		 * between pmd_trans_huge() and a pmd_none_or_clear_bad()
234 		 * check leading to a false positive and clearing.
235 		 * Hence, it's necessary to atomically read the PMD value
236 		 * for all the checks.
237 		 */
238 		if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) &&
239 		     pmd_none_or_clear_bad_unless_trans_huge(pmd))
240 			goto next;
241 
242 		/* invoke the mmu notifier if the pmd is populated */
243 		if (!range.start) {
244 			mmu_notifier_range_init(&range,
245 				MMU_NOTIFY_PROTECTION_VMA, 0,
246 				vma, vma->vm_mm, addr, end);
247 			mmu_notifier_invalidate_range_start(&range);
248 		}
249 
250 		if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
251 			if (next - addr != HPAGE_PMD_SIZE) {
252 				__split_huge_pmd(vma, pmd, addr, false, NULL);
253 			} else {
254 				int nr_ptes = change_huge_pmd(vma, pmd, addr,
255 							      newprot, cp_flags);
256 
257 				if (nr_ptes) {
258 					if (nr_ptes == HPAGE_PMD_NR) {
259 						pages += HPAGE_PMD_NR;
260 						nr_huge_updates++;
261 					}
262 
263 					/* huge pmd was handled */
264 					goto next;
265 				}
266 			}
267 			/* fall through, the trans huge pmd just split */
268 		}
269 		this_pages = change_pte_range(vma, pmd, addr, next, newprot,
270 					      cp_flags);
271 		pages += this_pages;
272 next:
273 		cond_resched();
274 	} while (pmd++, addr = next, addr != end);
275 
276 	if (range.start)
277 		mmu_notifier_invalidate_range_end(&range);
278 
279 	if (nr_huge_updates)
280 		count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
281 	return pages;
282 }
283 
change_pud_range(struct vm_area_struct * vma,p4d_t * p4d,unsigned long addr,unsigned long end,pgprot_t newprot,unsigned long cp_flags)284 static inline unsigned long change_pud_range(struct vm_area_struct *vma,
285 		p4d_t *p4d, unsigned long addr, unsigned long end,
286 		pgprot_t newprot, unsigned long cp_flags)
287 {
288 	pud_t *pud;
289 	unsigned long next;
290 	unsigned long pages = 0;
291 
292 	pud = pud_offset(p4d, addr);
293 	do {
294 		next = pud_addr_end(addr, end);
295 		if (pud_none_or_clear_bad(pud))
296 			continue;
297 		pages += change_pmd_range(vma, pud, addr, next, newprot,
298 					  cp_flags);
299 	} while (pud++, addr = next, addr != end);
300 
301 	return pages;
302 }
303 
change_p4d_range(struct vm_area_struct * vma,pgd_t * pgd,unsigned long addr,unsigned long end,pgprot_t newprot,unsigned long cp_flags)304 static inline unsigned long change_p4d_range(struct vm_area_struct *vma,
305 		pgd_t *pgd, unsigned long addr, unsigned long end,
306 		pgprot_t newprot, unsigned long cp_flags)
307 {
308 	p4d_t *p4d;
309 	unsigned long next;
310 	unsigned long pages = 0;
311 
312 	p4d = p4d_offset(pgd, addr);
313 	do {
314 		next = p4d_addr_end(addr, end);
315 		if (p4d_none_or_clear_bad(p4d))
316 			continue;
317 		pages += change_pud_range(vma, p4d, addr, next, newprot,
318 					  cp_flags);
319 	} while (p4d++, addr = next, addr != end);
320 
321 	return pages;
322 }
323 
change_protection_range(struct vm_area_struct * vma,unsigned long addr,unsigned long end,pgprot_t newprot,unsigned long cp_flags)324 static unsigned long change_protection_range(struct vm_area_struct *vma,
325 		unsigned long addr, unsigned long end, pgprot_t newprot,
326 		unsigned long cp_flags)
327 {
328 	struct mm_struct *mm = vma->vm_mm;
329 	pgd_t *pgd;
330 	unsigned long next;
331 	unsigned long start = addr;
332 	unsigned long pages = 0;
333 
334 	BUG_ON(addr >= end);
335 	pgd = pgd_offset(mm, addr);
336 	flush_cache_range(vma, addr, end);
337 	inc_tlb_flush_pending(mm);
338 	do {
339 		next = pgd_addr_end(addr, end);
340 		if (pgd_none_or_clear_bad(pgd))
341 			continue;
342 		pages += change_p4d_range(vma, pgd, addr, next, newprot,
343 					  cp_flags);
344 	} while (pgd++, addr = next, addr != end);
345 
346 	/* Only flush the TLB if we actually modified any entries: */
347 	if (pages)
348 		flush_tlb_range(vma, start, end);
349 	dec_tlb_flush_pending(mm);
350 
351 	return pages;
352 }
353 
change_protection(struct vm_area_struct * vma,unsigned long start,unsigned long end,pgprot_t newprot,unsigned long cp_flags)354 unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
355 		       unsigned long end, pgprot_t newprot,
356 		       unsigned long cp_flags)
357 {
358 	unsigned long pages;
359 
360 	BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
361 
362 	if (is_vm_hugetlb_page(vma))
363 		pages = hugetlb_change_protection(vma, start, end, newprot);
364 	else
365 		pages = change_protection_range(vma, start, end, newprot,
366 						cp_flags);
367 
368 	return pages;
369 }
370 
prot_none_pte_entry(pte_t * pte,unsigned long addr,unsigned long next,struct mm_walk * walk)371 static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
372 			       unsigned long next, struct mm_walk *walk)
373 {
374 	return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
375 		0 : -EACCES;
376 }
377 
prot_none_hugetlb_entry(pte_t * pte,unsigned long hmask,unsigned long addr,unsigned long next,struct mm_walk * walk)378 static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
379 				   unsigned long addr, unsigned long next,
380 				   struct mm_walk *walk)
381 {
382 	return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
383 		0 : -EACCES;
384 }
385 
prot_none_test(unsigned long addr,unsigned long next,struct mm_walk * walk)386 static int prot_none_test(unsigned long addr, unsigned long next,
387 			  struct mm_walk *walk)
388 {
389 	return 0;
390 }
391 
392 static const struct mm_walk_ops prot_none_walk_ops = {
393 	.pte_entry		= prot_none_pte_entry,
394 	.hugetlb_entry		= prot_none_hugetlb_entry,
395 	.test_walk		= prot_none_test,
396 };
397 
398 int
mprotect_fixup(struct vm_area_struct * vma,struct vm_area_struct ** pprev,unsigned long start,unsigned long end,unsigned long newflags)399 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
400 	unsigned long start, unsigned long end, unsigned long newflags)
401 {
402 	struct mm_struct *mm = vma->vm_mm;
403 	unsigned long oldflags = vma->vm_flags;
404 	long nrpages = (end - start) >> PAGE_SHIFT;
405 	unsigned long charged = 0;
406 	pgoff_t pgoff;
407 	int error;
408 	int dirty_accountable = 0;
409 
410 	if (newflags == oldflags) {
411 		*pprev = vma;
412 		return 0;
413 	}
414 
415 	/*
416 	 * Do PROT_NONE PFN permission checks here when we can still
417 	 * bail out without undoing a lot of state. This is a rather
418 	 * uncommon case, so doesn't need to be very optimized.
419 	 */
420 	if (arch_has_pfn_modify_check() &&
421 	    (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
422 	    (newflags & VM_ACCESS_FLAGS) == 0) {
423 		pgprot_t new_pgprot = vm_get_page_prot(newflags);
424 
425 		error = walk_page_range(current->mm, start, end,
426 				&prot_none_walk_ops, &new_pgprot);
427 		if (error)
428 			return error;
429 	}
430 
431 	/*
432 	 * If we make a private mapping writable we increase our commit;
433 	 * but (without finer accounting) cannot reduce our commit if we
434 	 * make it unwritable again. hugetlb mapping were accounted for
435 	 * even if read-only so there is no need to account for them here
436 	 */
437 	if (newflags & VM_WRITE) {
438 		/* Check space limits when area turns into data. */
439 		if (!may_expand_vm(mm, newflags, nrpages) &&
440 				may_expand_vm(mm, oldflags, nrpages))
441 			return -ENOMEM;
442 		if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
443 						VM_SHARED|VM_NORESERVE))) {
444 			charged = nrpages;
445 			if (security_vm_enough_memory_mm(mm, charged))
446 				return -ENOMEM;
447 			newflags |= VM_ACCOUNT;
448 		}
449 	}
450 
451 	/*
452 	 * First try to merge with previous and/or next vma.
453 	 */
454 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
455 	*pprev = vma_merge(mm, *pprev, start, end, newflags,
456 			   vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
457 			   vma->vm_userfaultfd_ctx, vma_get_anon_name(vma));
458 	if (*pprev) {
459 		vma = *pprev;
460 		VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
461 		goto success;
462 	}
463 
464 	*pprev = vma;
465 
466 	if (start != vma->vm_start) {
467 		error = split_vma(mm, vma, start, 1);
468 		if (error)
469 			goto fail;
470 	}
471 
472 	if (end != vma->vm_end) {
473 		error = split_vma(mm, vma, end, 0);
474 		if (error)
475 			goto fail;
476 	}
477 
478 success:
479 	/*
480 	 * vm_flags and vm_page_prot are protected by the mmap_lock
481 	 * held in write mode.
482 	 */
483 	vm_write_begin(vma);
484 	WRITE_ONCE(vma->vm_flags, newflags);
485 	dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot);
486 	vma_set_page_prot(vma);
487 
488 	change_protection(vma, start, end, vma->vm_page_prot,
489 			  dirty_accountable ? MM_CP_DIRTY_ACCT : 0);
490 	vm_write_end(vma);
491 
492 	/*
493 	 * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
494 	 * fault on access.
495 	 */
496 	if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
497 			(newflags & VM_WRITE)) {
498 		populate_vma_page_range(vma, start, end, NULL);
499 	}
500 
501 	vm_stat_account(mm, oldflags, -nrpages);
502 	vm_stat_account(mm, newflags, nrpages);
503 	perf_event_mmap(vma);
504 	return 0;
505 
506 fail:
507 	vm_unacct_memory(charged);
508 	return error;
509 }
510 
511 /*
512  * pkey==-1 when doing a legacy mprotect()
513  */
do_mprotect_pkey(unsigned long start,size_t len,unsigned long prot,int pkey)514 static int do_mprotect_pkey(unsigned long start, size_t len,
515 		unsigned long prot, int pkey)
516 {
517 	unsigned long nstart, end, tmp, reqprot;
518 	struct vm_area_struct *vma, *prev;
519 	int error = -EINVAL;
520 	const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
521 	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
522 				(prot & PROT_READ);
523 
524 	start = untagged_addr(start);
525 
526 	prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
527 	if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
528 		return -EINVAL;
529 
530 	if (start & ~PAGE_MASK)
531 		return -EINVAL;
532 	if (!len)
533 		return 0;
534 	len = PAGE_ALIGN(len);
535 	end = start + len;
536 	if (end <= start)
537 		return -ENOMEM;
538 	if (!arch_validate_prot(prot, start))
539 		return -EINVAL;
540 
541 	reqprot = prot;
542 
543 	if (mmap_write_lock_killable(current->mm))
544 		return -EINTR;
545 
546 	/*
547 	 * If userspace did not allocate the pkey, do not let
548 	 * them use it here.
549 	 */
550 	error = -EINVAL;
551 	if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
552 		goto out;
553 
554 	vma = find_vma(current->mm, start);
555 	error = -ENOMEM;
556 	if (!vma)
557 		goto out;
558 	prev = vma->vm_prev;
559 	if (unlikely(grows & PROT_GROWSDOWN)) {
560 		if (vma->vm_start >= end)
561 			goto out;
562 		start = vma->vm_start;
563 		error = -EINVAL;
564 		if (!(vma->vm_flags & VM_GROWSDOWN))
565 			goto out;
566 	} else {
567 		if (vma->vm_start > start)
568 			goto out;
569 		if (unlikely(grows & PROT_GROWSUP)) {
570 			end = vma->vm_end;
571 			error = -EINVAL;
572 			if (!(vma->vm_flags & VM_GROWSUP))
573 				goto out;
574 		}
575 	}
576 	if (start > vma->vm_start)
577 		prev = vma;
578 
579 	for (nstart = start ; ; ) {
580 		unsigned long mask_off_old_flags;
581 		unsigned long newflags;
582 		int new_vma_pkey;
583 
584 		/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
585 
586 		/* Does the application expect PROT_READ to imply PROT_EXEC */
587 		if (rier && (vma->vm_flags & VM_MAYEXEC))
588 			prot |= PROT_EXEC;
589 
590 		/*
591 		 * Each mprotect() call explicitly passes r/w/x permissions.
592 		 * If a permission is not passed to mprotect(), it must be
593 		 * cleared from the VMA.
594 		 */
595 		mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC |
596 					VM_FLAGS_CLEAR;
597 
598 		new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
599 		newflags = calc_vm_prot_bits(prot, new_vma_pkey);
600 		newflags |= (vma->vm_flags & ~mask_off_old_flags);
601 
602 		/* newflags >> 4 shift VM_MAY% in place of VM_% */
603 		if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
604 			error = -EACCES;
605 			goto out;
606 		}
607 
608 		/* Allow architectures to sanity-check the new flags */
609 		if (!arch_validate_flags(newflags)) {
610 			error = -EINVAL;
611 			goto out;
612 		}
613 
614 		error = security_file_mprotect(vma, reqprot, prot);
615 		if (error)
616 			goto out;
617 
618 		tmp = vma->vm_end;
619 		if (tmp > end)
620 			tmp = end;
621 		error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
622 		if (error)
623 			goto out;
624 		nstart = tmp;
625 
626 		if (nstart < prev->vm_end)
627 			nstart = prev->vm_end;
628 		if (nstart >= end)
629 			goto out;
630 
631 		vma = prev->vm_next;
632 		if (!vma || vma->vm_start != nstart) {
633 			error = -ENOMEM;
634 			goto out;
635 		}
636 		prot = reqprot;
637 	}
638 out:
639 	mmap_write_unlock(current->mm);
640 	return error;
641 }
642 
SYSCALL_DEFINE3(mprotect,unsigned long,start,size_t,len,unsigned long,prot)643 SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
644 		unsigned long, prot)
645 {
646 	return do_mprotect_pkey(start, len, prot, -1);
647 }
648 
649 #ifdef CONFIG_ARCH_HAS_PKEYS
650 
SYSCALL_DEFINE4(pkey_mprotect,unsigned long,start,size_t,len,unsigned long,prot,int,pkey)651 SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
652 		unsigned long, prot, int, pkey)
653 {
654 	return do_mprotect_pkey(start, len, prot, pkey);
655 }
656 
SYSCALL_DEFINE2(pkey_alloc,unsigned long,flags,unsigned long,init_val)657 SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
658 {
659 	int pkey;
660 	int ret;
661 
662 	/* No flags supported yet. */
663 	if (flags)
664 		return -EINVAL;
665 	/* check for unsupported init values */
666 	if (init_val & ~PKEY_ACCESS_MASK)
667 		return -EINVAL;
668 
669 	mmap_write_lock(current->mm);
670 	pkey = mm_pkey_alloc(current->mm);
671 
672 	ret = -ENOSPC;
673 	if (pkey == -1)
674 		goto out;
675 
676 	ret = arch_set_user_pkey_access(current, pkey, init_val);
677 	if (ret) {
678 		mm_pkey_free(current->mm, pkey);
679 		goto out;
680 	}
681 	ret = pkey;
682 out:
683 	mmap_write_unlock(current->mm);
684 	return ret;
685 }
686 
SYSCALL_DEFINE1(pkey_free,int,pkey)687 SYSCALL_DEFINE1(pkey_free, int, pkey)
688 {
689 	int ret;
690 
691 	mmap_write_lock(current->mm);
692 	ret = mm_pkey_free(current->mm, pkey);
693 	mmap_write_unlock(current->mm);
694 
695 	/*
696 	 * We could provie warnings or errors if any VMA still
697 	 * has the pkey set here.
698 	 */
699 	return ret;
700 }
701 
702 #endif /* CONFIG_ARCH_HAS_PKEYS */
703