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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * mm/mprotect.c | |
4 | * | |
5 | * (C) Copyright 1994 Linus Torvalds | |
6 | * (C) Copyright 2002 Christoph Hellwig | |
7 | * | |
046c6884 | 8 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
9 | * (C) Copyright 2002 Red Hat Inc, All Rights Reserved |
10 | */ | |
11 | ||
a520110e | 12 | #include <linux/pagewalk.h> |
1da177e4 | 13 | #include <linux/hugetlb.h> |
1da177e4 LT |
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> | |
0697212a CL |
22 | #include <linux/swap.h> |
23 | #include <linux/swapops.h> | |
cddb8a5c | 24 | #include <linux/mmu_notifier.h> |
64cdd548 | 25 | #include <linux/migrate.h> |
cdd6c482 | 26 | #include <linux/perf_event.h> |
e8c24d3a | 27 | #include <linux/pkeys.h> |
64a9a34e | 28 | #include <linux/ksm.h> |
7c0f6ba6 | 29 | #include <linux/uaccess.h> |
09a913a7 | 30 | #include <linux/mm_inline.h> |
1da177e4 LT |
31 | #include <asm/pgtable.h> |
32 | #include <asm/cacheflush.h> | |
e8c24d3a | 33 | #include <asm/mmu_context.h> |
1da177e4 LT |
34 | #include <asm/tlbflush.h> |
35 | ||
36f88188 KS |
36 | #include "internal.h" |
37 | ||
4b10e7d5 | 38 | static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
c1e6098b | 39 | unsigned long addr, unsigned long end, pgprot_t newprot, |
0f19c179 | 40 | int dirty_accountable, int prot_numa) |
1da177e4 | 41 | { |
0697212a | 42 | pte_t *pte, oldpte; |
705e87c0 | 43 | spinlock_t *ptl; |
7da4d641 | 44 | unsigned long pages = 0; |
3e321587 | 45 | int target_node = NUMA_NO_NODE; |
1da177e4 | 46 | |
175ad4f1 AA |
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); | |
1ad9f620 | 62 | |
3e321587 AK |
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 | ||
3ea27719 | 68 | flush_tlb_batched_pending(vma->vm_mm); |
6606c3e0 | 69 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 70 | do { |
0697212a CL |
71 | oldpte = *pte; |
72 | if (pte_present(oldpte)) { | |
1da177e4 | 73 | pte_t ptent; |
b191f9b1 | 74 | bool preserve_write = prot_numa && pte_write(oldpte); |
1da177e4 | 75 | |
e944fd67 MG |
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 | ||
a818f536 HY |
83 | /* Avoid TLB flush if possible */ |
84 | if (pte_protnone(oldpte)) | |
85 | continue; | |
86 | ||
e944fd67 MG |
87 | page = vm_normal_page(vma, addr, oldpte); |
88 | if (!page || PageKsm(page)) | |
89 | continue; | |
10c1045f | 90 | |
859d4adc HW |
91 | /* Also skip shared copy-on-write pages */ |
92 | if (is_cow_mapping(vma->vm_flags) && | |
93 | page_mapcount(page) != 1) | |
94 | continue; | |
95 | ||
09a913a7 MG |
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_cache(page) && PageDirty(page)) | |
102 | continue; | |
103 | ||
3e321587 AK |
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; | |
e944fd67 MG |
110 | } |
111 | ||
04a86453 AK |
112 | oldpte = ptep_modify_prot_start(vma, addr, pte); |
113 | ptent = pte_modify(oldpte, newprot); | |
b191f9b1 | 114 | if (preserve_write) |
288bc549 | 115 | ptent = pte_mk_savedwrite(ptent); |
4b10e7d5 | 116 | |
8a0516ed MG |
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); | |
4b10e7d5 | 122 | } |
04a86453 | 123 | ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); |
8a0516ed | 124 | pages++; |
0661a336 | 125 | } else if (IS_ENABLED(CONFIG_MIGRATION)) { |
0697212a CL |
126 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
127 | ||
128 | if (is_write_migration_entry(entry)) { | |
c3d16e16 | 129 | pte_t newpte; |
0697212a CL |
130 | /* |
131 | * A protection check is difficult so | |
132 | * just be safe and disable write | |
133 | */ | |
134 | make_migration_entry_read(&entry); | |
c3d16e16 CG |
135 | newpte = swp_entry_to_pte(entry); |
136 | if (pte_swp_soft_dirty(oldpte)) | |
137 | newpte = pte_swp_mksoft_dirty(newpte); | |
94393c78 | 138 | set_pte_at(vma->vm_mm, addr, pte, newpte); |
e920e14c MG |
139 | |
140 | pages++; | |
0697212a | 141 | } |
5042db43 JG |
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); | |
94393c78 | 152 | set_pte_at(vma->vm_mm, addr, pte, newpte); |
5042db43 JG |
153 | |
154 | pages++; | |
155 | } | |
1da177e4 LT |
156 | } |
157 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 158 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 159 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 PZ |
160 | |
161 | return pages; | |
1da177e4 LT |
162 | } |
163 | ||
8b272b3c MG |
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 | ||
7d12efae AM |
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) | |
1da177e4 LT |
192 | { |
193 | pmd_t *pmd; | |
194 | unsigned long next; | |
7da4d641 | 195 | unsigned long pages = 0; |
72403b4a | 196 | unsigned long nr_huge_updates = 0; |
ac46d4f3 JG |
197 | struct mmu_notifier_range range; |
198 | ||
199 | range.start = 0; | |
1da177e4 LT |
200 | |
201 | pmd = pmd_offset(pud, addr); | |
202 | do { | |
25cbbef1 MG |
203 | unsigned long this_pages; |
204 | ||
1da177e4 | 205 | next = pmd_addr_end(addr, end); |
8b272b3c MG |
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)) | |
4991c09c | 217 | goto next; |
a5338093 RR |
218 | |
219 | /* invoke the mmu notifier if the pmd is populated */ | |
ac46d4f3 | 220 | if (!range.start) { |
7269f999 JG |
221 | mmu_notifier_range_init(&range, |
222 | MMU_NOTIFY_PROTECTION_VMA, 0, | |
223 | vma, vma->vm_mm, addr, end); | |
ac46d4f3 | 224 | mmu_notifier_invalidate_range_start(&range); |
a5338093 RR |
225 | } |
226 | ||
84c3fc4e | 227 | if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { |
6b9116a6 | 228 | if (next - addr != HPAGE_PMD_SIZE) { |
fd60775a | 229 | __split_huge_pmd(vma, pmd, addr, false, NULL); |
6b9116a6 | 230 | } else { |
f123d74a | 231 | int nr_ptes = change_huge_pmd(vma, pmd, addr, |
e944fd67 | 232 | newprot, prot_numa); |
f123d74a MG |
233 | |
234 | if (nr_ptes) { | |
72403b4a MG |
235 | if (nr_ptes == HPAGE_PMD_NR) { |
236 | pages += HPAGE_PMD_NR; | |
237 | nr_huge_updates++; | |
238 | } | |
1ad9f620 MG |
239 | |
240 | /* huge pmd was handled */ | |
4991c09c | 241 | goto next; |
f123d74a | 242 | } |
7da4d641 | 243 | } |
88a9ab6e | 244 | /* fall through, the trans huge pmd just split */ |
cd7548ab | 245 | } |
25cbbef1 | 246 | this_pages = change_pte_range(vma, pmd, addr, next, newprot, |
0f19c179 | 247 | dirty_accountable, prot_numa); |
25cbbef1 | 248 | pages += this_pages; |
4991c09c AK |
249 | next: |
250 | cond_resched(); | |
1da177e4 | 251 | } while (pmd++, addr = next, addr != end); |
7da4d641 | 252 | |
ac46d4f3 JG |
253 | if (range.start) |
254 | mmu_notifier_invalidate_range_end(&range); | |
a5338093 | 255 | |
72403b4a MG |
256 | if (nr_huge_updates) |
257 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
7da4d641 | 258 | return pages; |
1da177e4 LT |
259 | } |
260 | ||
7d12efae | 261 | static inline unsigned long change_pud_range(struct vm_area_struct *vma, |
c2febafc | 262 | p4d_t *p4d, unsigned long addr, unsigned long end, |
7d12efae | 263 | pgprot_t newprot, int dirty_accountable, int prot_numa) |
1da177e4 LT |
264 | { |
265 | pud_t *pud; | |
266 | unsigned long next; | |
7da4d641 | 267 | unsigned long pages = 0; |
1da177e4 | 268 | |
c2febafc | 269 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
270 | do { |
271 | next = pud_addr_end(addr, end); | |
272 | if (pud_none_or_clear_bad(pud)) | |
273 | continue; | |
7da4d641 | 274 | pages += change_pmd_range(vma, pud, addr, next, newprot, |
4b10e7d5 | 275 | dirty_accountable, prot_numa); |
1da177e4 | 276 | } while (pud++, addr = next, addr != end); |
7da4d641 PZ |
277 | |
278 | return pages; | |
1da177e4 LT |
279 | } |
280 | ||
c2febafc KS |
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 | ||
7da4d641 | 301 | static unsigned long change_protection_range(struct vm_area_struct *vma, |
c1e6098b | 302 | unsigned long addr, unsigned long end, pgprot_t newprot, |
4b10e7d5 | 303 | int dirty_accountable, int prot_numa) |
1da177e4 LT |
304 | { |
305 | struct mm_struct *mm = vma->vm_mm; | |
306 | pgd_t *pgd; | |
307 | unsigned long next; | |
308 | unsigned long start = addr; | |
7da4d641 | 309 | unsigned long pages = 0; |
1da177e4 LT |
310 | |
311 | BUG_ON(addr >= end); | |
312 | pgd = pgd_offset(mm, addr); | |
313 | flush_cache_range(vma, addr, end); | |
16af97dc | 314 | inc_tlb_flush_pending(mm); |
1da177e4 LT |
315 | do { |
316 | next = pgd_addr_end(addr, end); | |
317 | if (pgd_none_or_clear_bad(pgd)) | |
318 | continue; | |
c2febafc | 319 | pages += change_p4d_range(vma, pgd, addr, next, newprot, |
4b10e7d5 | 320 | dirty_accountable, prot_numa); |
1da177e4 | 321 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 322 | |
1233d588 IM |
323 | /* Only flush the TLB if we actually modified any entries: */ |
324 | if (pages) | |
325 | flush_tlb_range(vma, start, end); | |
16af97dc | 326 | dec_tlb_flush_pending(mm); |
7da4d641 PZ |
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, | |
4b10e7d5 | 333 | int dirty_accountable, int prot_numa) |
7da4d641 | 334 | { |
7da4d641 PZ |
335 | unsigned long pages; |
336 | ||
7da4d641 PZ |
337 | if (is_vm_hugetlb_page(vma)) |
338 | pages = hugetlb_change_protection(vma, start, end, newprot); | |
339 | else | |
4b10e7d5 | 340 | pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa); |
7da4d641 PZ |
341 | |
342 | return pages; | |
1da177e4 LT |
343 | } |
344 | ||
42e4089c AK |
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 | ||
7b86ac33 CH |
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 | }; | |
42e4089c | 371 | |
b6a2fea3 | 372 | int |
1da177e4 LT |
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; | |
1da177e4 LT |
380 | pgoff_t pgoff; |
381 | int error; | |
c1e6098b | 382 | int dirty_accountable = 0; |
1da177e4 LT |
383 | |
384 | if (newflags == oldflags) { | |
385 | *pprev = vma; | |
386 | return 0; | |
387 | } | |
388 | ||
42e4089c AK |
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) { | |
7b86ac33 CH |
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); | |
42e4089c AK |
401 | if (error) |
402 | return error; | |
403 | } | |
404 | ||
1da177e4 LT |
405 | /* |
406 | * If we make a private mapping writable we increase our commit; | |
407 | * but (without finer accounting) cannot reduce our commit if we | |
5a6fe125 MG |
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 | |
1da177e4 LT |
410 | */ |
411 | if (newflags & VM_WRITE) { | |
84638335 KK |
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; | |
5a6fe125 | 416 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 417 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 418 | charged = nrpages; |
191c5424 | 419 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
420 | return -ENOMEM; |
421 | newflags |= VM_ACCOUNT; | |
422 | } | |
423 | } | |
424 | ||
1da177e4 LT |
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, | |
19a809af AA |
430 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), |
431 | vma->vm_userfaultfd_ctx); | |
1da177e4 LT |
432 | if (*pprev) { |
433 | vma = *pprev; | |
e86f15ee | 434 | VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY); |
1da177e4 LT |
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; | |
6d2329f8 | 458 | dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot); |
64e45507 | 459 | vma_set_page_prot(vma); |
d08b3851 | 460 | |
7d12efae AM |
461 | change_protection(vma, start, end, vma->vm_page_prot, |
462 | dirty_accountable, 0); | |
7da4d641 | 463 | |
36f88188 KS |
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 | ||
84638335 KK |
473 | vm_stat_account(mm, oldflags, -nrpages); |
474 | vm_stat_account(mm, newflags, nrpages); | |
63bfd738 | 475 | perf_event_mmap(vma); |
1da177e4 LT |
476 | return 0; |
477 | ||
478 | fail: | |
479 | vm_unacct_memory(charged); | |
480 | return error; | |
481 | } | |
482 | ||
7d06d9c9 DH |
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) | |
1da177e4 | 488 | { |
62b5f7d0 | 489 | unsigned long nstart, end, tmp, reqprot; |
1da177e4 LT |
490 | struct vm_area_struct *vma, *prev; |
491 | int error = -EINVAL; | |
492 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); | |
f138556d PK |
493 | const bool rier = (current->personality & READ_IMPLIES_EXEC) && |
494 | (prot & PROT_READ); | |
495 | ||
057d3389 AK |
496 | start = untagged_addr(start); |
497 | ||
1da177e4 LT |
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; | |
9035cf9a | 510 | if (!arch_validate_prot(prot, start)) |
1da177e4 LT |
511 | return -EINVAL; |
512 | ||
513 | reqprot = prot; | |
1da177e4 | 514 | |
dc0ef0df MH |
515 | if (down_write_killable(¤t->mm->mmap_sem)) |
516 | return -EINTR; | |
1da177e4 | 517 | |
e8c24d3a DH |
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 | ||
097d5910 | 526 | vma = find_vma(current->mm, start); |
1da177e4 LT |
527 | error = -ENOMEM; |
528 | if (!vma) | |
529 | goto out; | |
097d5910 | 530 | prev = vma->vm_prev; |
1da177e4 LT |
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; | |
7d12efae | 538 | } else { |
1da177e4 LT |
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 ; ; ) { | |
a8502b67 | 552 | unsigned long mask_off_old_flags; |
1da177e4 | 553 | unsigned long newflags; |
7d06d9c9 | 554 | int new_vma_pkey; |
1da177e4 | 555 | |
7d12efae | 556 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
1da177e4 | 557 | |
f138556d PK |
558 | /* Does the application expect PROT_READ to imply PROT_EXEC */ |
559 | if (rier && (vma->vm_flags & VM_MAYEXEC)) | |
560 | prot |= PROT_EXEC; | |
561 | ||
a8502b67 DH |
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 | | |
2c2d57b5 | 568 | VM_FLAGS_CLEAR; |
a8502b67 | 569 | |
7d06d9c9 DH |
570 | new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); |
571 | newflags = calc_vm_prot_bits(prot, new_vma_pkey); | |
a8502b67 | 572 | newflags |= (vma->vm_flags & ~mask_off_old_flags); |
1da177e4 | 573 | |
7e2cff42 PBG |
574 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
575 | if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) { | |
1da177e4 LT |
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 | } | |
f138556d | 602 | prot = reqprot; |
1da177e4 LT |
603 | } |
604 | out: | |
605 | up_write(¤t->mm->mmap_sem); | |
606 | return error; | |
607 | } | |
7d06d9c9 DH |
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 | ||
c7142aea HC |
615 | #ifdef CONFIG_ARCH_HAS_PKEYS |
616 | ||
7d06d9c9 DH |
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 | } | |
e8c24d3a DH |
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 | } | |
c7142aea HC |
667 | |
668 | #endif /* CONFIG_ARCH_HAS_PKEYS */ |