Commit | Line | Data |
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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> |
ca5999fd | 31 | #include <linux/pgtable.h> |
1da177e4 | 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, |
58705444 | 40 | unsigned long cp_flags) |
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; |
58705444 PX |
46 | bool dirty_accountable = cp_flags & MM_CP_DIRTY_ACCT; |
47 | bool prot_numa = cp_flags & MM_CP_PROT_NUMA; | |
292924b2 PX |
48 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
49 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; | |
1da177e4 | 50 | |
175ad4f1 | 51 | /* |
c1e8d7c6 | 52 | * Can be called with only the mmap_lock for reading by |
175ad4f1 AA |
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 | |
c1e8d7c6 | 62 | * from under us even if the mmap_lock is only hold for |
175ad4f1 AA |
63 | * reading. |
64 | */ | |
65 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
1ad9f620 | 66 | |
3e321587 AK |
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 | ||
3ea27719 | 72 | flush_tlb_batched_pending(vma->vm_mm); |
6606c3e0 | 73 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 74 | do { |
0697212a CL |
75 | oldpte = *pte; |
76 | if (pte_present(oldpte)) { | |
1da177e4 | 77 | pte_t ptent; |
b191f9b1 | 78 | bool preserve_write = prot_numa && pte_write(oldpte); |
1da177e4 | 79 | |
e944fd67 MG |
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 | ||
a818f536 HY |
87 | /* Avoid TLB flush if possible */ |
88 | if (pte_protnone(oldpte)) | |
89 | continue; | |
90 | ||
e944fd67 MG |
91 | page = vm_normal_page(vma, addr, oldpte); |
92 | if (!page || PageKsm(page)) | |
93 | continue; | |
10c1045f | 94 | |
859d4adc HW |
95 | /* Also skip shared copy-on-write pages */ |
96 | if (is_cow_mapping(vma->vm_flags) && | |
97 | page_mapcount(page) != 1) | |
98 | continue; | |
99 | ||
09a913a7 MG |
100 | /* |
101 | * While migration can move some dirty pages, | |
102 | * it cannot move them all from MIGRATE_ASYNC | |
103 | * context. | |
104 | */ | |
9de4f22a | 105 | if (page_is_file_lru(page) && PageDirty(page)) |
09a913a7 MG |
106 | continue; |
107 | ||
3e321587 AK |
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; | |
e944fd67 MG |
114 | } |
115 | ||
04a86453 AK |
116 | oldpte = ptep_modify_prot_start(vma, addr, pte); |
117 | ptent = pte_modify(oldpte, newprot); | |
b191f9b1 | 118 | if (preserve_write) |
288bc549 | 119 | ptent = pte_mk_savedwrite(ptent); |
4b10e7d5 | 120 | |
292924b2 PX |
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 | ||
8a0516ed MG |
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); | |
4b10e7d5 | 139 | } |
04a86453 | 140 | ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent); |
8a0516ed | 141 | pages++; |
f45ec5ff | 142 | } else if (is_swap_pte(oldpte)) { |
0697212a | 143 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
f45ec5ff | 144 | pte_t newpte; |
0697212a | 145 | |
4dd845b5 | 146 | if (is_writable_migration_entry(entry)) { |
0697212a CL |
147 | /* |
148 | * A protection check is difficult so | |
149 | * just be safe and disable write | |
150 | */ | |
4dd845b5 AP |
151 | entry = make_readable_migration_entry( |
152 | swp_offset(entry)); | |
c3d16e16 CG |
153 | newpte = swp_entry_to_pte(entry); |
154 | if (pte_swp_soft_dirty(oldpte)) | |
155 | newpte = pte_swp_mksoft_dirty(newpte); | |
f45ec5ff PX |
156 | if (pte_swp_uffd_wp(oldpte)) |
157 | newpte = pte_swp_mkuffd_wp(newpte); | |
4dd845b5 | 158 | } else if (is_writable_device_private_entry(entry)) { |
5042db43 JG |
159 | /* |
160 | * We do not preserve soft-dirtiness. See | |
161 | * copy_one_pte() for explanation. | |
162 | */ | |
4dd845b5 AP |
163 | entry = make_readable_device_private_entry( |
164 | swp_offset(entry)); | |
5042db43 | 165 | newpte = swp_entry_to_pte(entry); |
f45ec5ff PX |
166 | if (pte_swp_uffd_wp(oldpte)) |
167 | newpte = pte_swp_mkuffd_wp(newpte); | |
b756a3b5 AP |
168 | } else if (is_writable_device_exclusive_entry(entry)) { |
169 | entry = make_readable_device_exclusive_entry( | |
170 | swp_offset(entry)); | |
171 | newpte = swp_entry_to_pte(entry); | |
172 | if (pte_swp_soft_dirty(oldpte)) | |
173 | newpte = pte_swp_mksoft_dirty(newpte); | |
174 | if (pte_swp_uffd_wp(oldpte)) | |
175 | newpte = pte_swp_mkuffd_wp(newpte); | |
f45ec5ff PX |
176 | } else { |
177 | newpte = oldpte; | |
178 | } | |
5042db43 | 179 | |
f45ec5ff PX |
180 | if (uffd_wp) |
181 | newpte = pte_swp_mkuffd_wp(newpte); | |
182 | else if (uffd_wp_resolve) | |
183 | newpte = pte_swp_clear_uffd_wp(newpte); | |
184 | ||
185 | if (!pte_same(oldpte, newpte)) { | |
186 | set_pte_at(vma->vm_mm, addr, pte, newpte); | |
5042db43 JG |
187 | pages++; |
188 | } | |
1da177e4 LT |
189 | } |
190 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 191 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 192 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 PZ |
193 | |
194 | return pages; | |
1da177e4 LT |
195 | } |
196 | ||
8b272b3c MG |
197 | /* |
198 | * Used when setting automatic NUMA hinting protection where it is | |
199 | * critical that a numa hinting PMD is not confused with a bad PMD. | |
200 | */ | |
201 | static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) | |
202 | { | |
203 | pmd_t pmdval = pmd_read_atomic(pmd); | |
204 | ||
205 | /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */ | |
206 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
207 | barrier(); | |
208 | #endif | |
209 | ||
210 | if (pmd_none(pmdval)) | |
211 | return 1; | |
212 | if (pmd_trans_huge(pmdval)) | |
213 | return 0; | |
214 | if (unlikely(pmd_bad(pmdval))) { | |
215 | pmd_clear_bad(pmd); | |
216 | return 1; | |
217 | } | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
7d12efae AM |
222 | static inline unsigned long change_pmd_range(struct vm_area_struct *vma, |
223 | pud_t *pud, unsigned long addr, unsigned long end, | |
58705444 | 224 | pgprot_t newprot, unsigned long cp_flags) |
1da177e4 LT |
225 | { |
226 | pmd_t *pmd; | |
227 | unsigned long next; | |
7da4d641 | 228 | unsigned long pages = 0; |
72403b4a | 229 | unsigned long nr_huge_updates = 0; |
ac46d4f3 JG |
230 | struct mmu_notifier_range range; |
231 | ||
232 | range.start = 0; | |
1da177e4 LT |
233 | |
234 | pmd = pmd_offset(pud, addr); | |
235 | do { | |
25cbbef1 MG |
236 | unsigned long this_pages; |
237 | ||
1da177e4 | 238 | next = pmd_addr_end(addr, end); |
8b272b3c MG |
239 | |
240 | /* | |
c1e8d7c6 | 241 | * Automatic NUMA balancing walks the tables with mmap_lock |
8b272b3c MG |
242 | * held for read. It's possible a parallel update to occur |
243 | * between pmd_trans_huge() and a pmd_none_or_clear_bad() | |
244 | * check leading to a false positive and clearing. | |
245 | * Hence, it's necessary to atomically read the PMD value | |
246 | * for all the checks. | |
247 | */ | |
248 | if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) && | |
249 | pmd_none_or_clear_bad_unless_trans_huge(pmd)) | |
4991c09c | 250 | goto next; |
a5338093 RR |
251 | |
252 | /* invoke the mmu notifier if the pmd is populated */ | |
ac46d4f3 | 253 | if (!range.start) { |
7269f999 JG |
254 | mmu_notifier_range_init(&range, |
255 | MMU_NOTIFY_PROTECTION_VMA, 0, | |
256 | vma, vma->vm_mm, addr, end); | |
ac46d4f3 | 257 | mmu_notifier_invalidate_range_start(&range); |
a5338093 RR |
258 | } |
259 | ||
84c3fc4e | 260 | if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { |
6b9116a6 | 261 | if (next - addr != HPAGE_PMD_SIZE) { |
fd60775a | 262 | __split_huge_pmd(vma, pmd, addr, false, NULL); |
6b9116a6 | 263 | } else { |
f123d74a | 264 | int nr_ptes = change_huge_pmd(vma, pmd, addr, |
58705444 | 265 | newprot, cp_flags); |
f123d74a MG |
266 | |
267 | if (nr_ptes) { | |
72403b4a MG |
268 | if (nr_ptes == HPAGE_PMD_NR) { |
269 | pages += HPAGE_PMD_NR; | |
270 | nr_huge_updates++; | |
271 | } | |
1ad9f620 MG |
272 | |
273 | /* huge pmd was handled */ | |
4991c09c | 274 | goto next; |
f123d74a | 275 | } |
7da4d641 | 276 | } |
88a9ab6e | 277 | /* fall through, the trans huge pmd just split */ |
cd7548ab | 278 | } |
25cbbef1 | 279 | this_pages = change_pte_range(vma, pmd, addr, next, newprot, |
58705444 | 280 | cp_flags); |
25cbbef1 | 281 | pages += this_pages; |
4991c09c AK |
282 | next: |
283 | cond_resched(); | |
1da177e4 | 284 | } while (pmd++, addr = next, addr != end); |
7da4d641 | 285 | |
ac46d4f3 JG |
286 | if (range.start) |
287 | mmu_notifier_invalidate_range_end(&range); | |
a5338093 | 288 | |
72403b4a MG |
289 | if (nr_huge_updates) |
290 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
7da4d641 | 291 | return pages; |
1da177e4 LT |
292 | } |
293 | ||
7d12efae | 294 | static inline unsigned long change_pud_range(struct vm_area_struct *vma, |
c2febafc | 295 | p4d_t *p4d, unsigned long addr, unsigned long end, |
58705444 | 296 | pgprot_t newprot, unsigned long cp_flags) |
1da177e4 LT |
297 | { |
298 | pud_t *pud; | |
299 | unsigned long next; | |
7da4d641 | 300 | unsigned long pages = 0; |
1da177e4 | 301 | |
c2febafc | 302 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
303 | do { |
304 | next = pud_addr_end(addr, end); | |
305 | if (pud_none_or_clear_bad(pud)) | |
306 | continue; | |
7da4d641 | 307 | pages += change_pmd_range(vma, pud, addr, next, newprot, |
58705444 | 308 | cp_flags); |
1da177e4 | 309 | } while (pud++, addr = next, addr != end); |
7da4d641 PZ |
310 | |
311 | return pages; | |
1da177e4 LT |
312 | } |
313 | ||
c2febafc KS |
314 | static inline unsigned long change_p4d_range(struct vm_area_struct *vma, |
315 | pgd_t *pgd, unsigned long addr, unsigned long end, | |
58705444 | 316 | pgprot_t newprot, unsigned long cp_flags) |
c2febafc KS |
317 | { |
318 | p4d_t *p4d; | |
319 | unsigned long next; | |
320 | unsigned long pages = 0; | |
321 | ||
322 | p4d = p4d_offset(pgd, addr); | |
323 | do { | |
324 | next = p4d_addr_end(addr, end); | |
325 | if (p4d_none_or_clear_bad(p4d)) | |
326 | continue; | |
327 | pages += change_pud_range(vma, p4d, addr, next, newprot, | |
58705444 | 328 | cp_flags); |
c2febafc KS |
329 | } while (p4d++, addr = next, addr != end); |
330 | ||
331 | return pages; | |
332 | } | |
333 | ||
7da4d641 | 334 | static unsigned long change_protection_range(struct vm_area_struct *vma, |
c1e6098b | 335 | unsigned long addr, unsigned long end, pgprot_t newprot, |
58705444 | 336 | unsigned long cp_flags) |
1da177e4 LT |
337 | { |
338 | struct mm_struct *mm = vma->vm_mm; | |
339 | pgd_t *pgd; | |
340 | unsigned long next; | |
341 | unsigned long start = addr; | |
7da4d641 | 342 | unsigned long pages = 0; |
1da177e4 LT |
343 | |
344 | BUG_ON(addr >= end); | |
345 | pgd = pgd_offset(mm, addr); | |
346 | flush_cache_range(vma, addr, end); | |
16af97dc | 347 | inc_tlb_flush_pending(mm); |
1da177e4 LT |
348 | do { |
349 | next = pgd_addr_end(addr, end); | |
350 | if (pgd_none_or_clear_bad(pgd)) | |
351 | continue; | |
c2febafc | 352 | pages += change_p4d_range(vma, pgd, addr, next, newprot, |
58705444 | 353 | cp_flags); |
1da177e4 | 354 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 355 | |
1233d588 IM |
356 | /* Only flush the TLB if we actually modified any entries: */ |
357 | if (pages) | |
358 | flush_tlb_range(vma, start, end); | |
16af97dc | 359 | dec_tlb_flush_pending(mm); |
7da4d641 PZ |
360 | |
361 | return pages; | |
362 | } | |
363 | ||
364 | unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, | |
365 | unsigned long end, pgprot_t newprot, | |
58705444 | 366 | unsigned long cp_flags) |
7da4d641 | 367 | { |
7da4d641 PZ |
368 | unsigned long pages; |
369 | ||
292924b2 PX |
370 | BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL); |
371 | ||
7da4d641 PZ |
372 | if (is_vm_hugetlb_page(vma)) |
373 | pages = hugetlb_change_protection(vma, start, end, newprot); | |
374 | else | |
58705444 PX |
375 | pages = change_protection_range(vma, start, end, newprot, |
376 | cp_flags); | |
7da4d641 PZ |
377 | |
378 | return pages; | |
1da177e4 LT |
379 | } |
380 | ||
42e4089c AK |
381 | static int prot_none_pte_entry(pte_t *pte, unsigned long addr, |
382 | unsigned long next, struct mm_walk *walk) | |
383 | { | |
384 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
385 | 0 : -EACCES; | |
386 | } | |
387 | ||
388 | static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, | |
389 | unsigned long addr, unsigned long next, | |
390 | struct mm_walk *walk) | |
391 | { | |
392 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
393 | 0 : -EACCES; | |
394 | } | |
395 | ||
396 | static int prot_none_test(unsigned long addr, unsigned long next, | |
397 | struct mm_walk *walk) | |
398 | { | |
399 | return 0; | |
400 | } | |
401 | ||
7b86ac33 CH |
402 | static const struct mm_walk_ops prot_none_walk_ops = { |
403 | .pte_entry = prot_none_pte_entry, | |
404 | .hugetlb_entry = prot_none_hugetlb_entry, | |
405 | .test_walk = prot_none_test, | |
406 | }; | |
42e4089c | 407 | |
b6a2fea3 | 408 | int |
1da177e4 LT |
409 | mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, |
410 | unsigned long start, unsigned long end, unsigned long newflags) | |
411 | { | |
412 | struct mm_struct *mm = vma->vm_mm; | |
413 | unsigned long oldflags = vma->vm_flags; | |
414 | long nrpages = (end - start) >> PAGE_SHIFT; | |
415 | unsigned long charged = 0; | |
1da177e4 LT |
416 | pgoff_t pgoff; |
417 | int error; | |
c1e6098b | 418 | int dirty_accountable = 0; |
1da177e4 LT |
419 | |
420 | if (newflags == oldflags) { | |
421 | *pprev = vma; | |
422 | return 0; | |
423 | } | |
424 | ||
42e4089c AK |
425 | /* |
426 | * Do PROT_NONE PFN permission checks here when we can still | |
427 | * bail out without undoing a lot of state. This is a rather | |
428 | * uncommon case, so doesn't need to be very optimized. | |
429 | */ | |
430 | if (arch_has_pfn_modify_check() && | |
431 | (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && | |
6cb4d9a2 | 432 | (newflags & VM_ACCESS_FLAGS) == 0) { |
7b86ac33 CH |
433 | pgprot_t new_pgprot = vm_get_page_prot(newflags); |
434 | ||
435 | error = walk_page_range(current->mm, start, end, | |
436 | &prot_none_walk_ops, &new_pgprot); | |
42e4089c AK |
437 | if (error) |
438 | return error; | |
439 | } | |
440 | ||
1da177e4 LT |
441 | /* |
442 | * If we make a private mapping writable we increase our commit; | |
443 | * but (without finer accounting) cannot reduce our commit if we | |
5a6fe125 MG |
444 | * make it unwritable again. hugetlb mapping were accounted for |
445 | * even if read-only so there is no need to account for them here | |
1da177e4 LT |
446 | */ |
447 | if (newflags & VM_WRITE) { | |
84638335 KK |
448 | /* Check space limits when area turns into data. */ |
449 | if (!may_expand_vm(mm, newflags, nrpages) && | |
450 | may_expand_vm(mm, oldflags, nrpages)) | |
451 | return -ENOMEM; | |
5a6fe125 | 452 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 453 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 454 | charged = nrpages; |
191c5424 | 455 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
456 | return -ENOMEM; |
457 | newflags |= VM_ACCOUNT; | |
458 | } | |
459 | } | |
460 | ||
1da177e4 LT |
461 | /* |
462 | * First try to merge with previous and/or next vma. | |
463 | */ | |
464 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
465 | *pprev = vma_merge(mm, *pprev, start, end, newflags, | |
19a809af AA |
466 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), |
467 | vma->vm_userfaultfd_ctx); | |
1da177e4 LT |
468 | if (*pprev) { |
469 | vma = *pprev; | |
e86f15ee | 470 | VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY); |
1da177e4 LT |
471 | goto success; |
472 | } | |
473 | ||
474 | *pprev = vma; | |
475 | ||
476 | if (start != vma->vm_start) { | |
477 | error = split_vma(mm, vma, start, 1); | |
478 | if (error) | |
479 | goto fail; | |
480 | } | |
481 | ||
482 | if (end != vma->vm_end) { | |
483 | error = split_vma(mm, vma, end, 0); | |
484 | if (error) | |
485 | goto fail; | |
486 | } | |
487 | ||
488 | success: | |
489 | /* | |
c1e8d7c6 | 490 | * vm_flags and vm_page_prot are protected by the mmap_lock |
1da177e4 LT |
491 | * held in write mode. |
492 | */ | |
493 | vma->vm_flags = newflags; | |
6d2329f8 | 494 | dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot); |
64e45507 | 495 | vma_set_page_prot(vma); |
d08b3851 | 496 | |
7d12efae | 497 | change_protection(vma, start, end, vma->vm_page_prot, |
58705444 | 498 | dirty_accountable ? MM_CP_DIRTY_ACCT : 0); |
7da4d641 | 499 | |
36f88188 KS |
500 | /* |
501 | * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major | |
502 | * fault on access. | |
503 | */ | |
504 | if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED && | |
505 | (newflags & VM_WRITE)) { | |
506 | populate_vma_page_range(vma, start, end, NULL); | |
507 | } | |
508 | ||
84638335 KK |
509 | vm_stat_account(mm, oldflags, -nrpages); |
510 | vm_stat_account(mm, newflags, nrpages); | |
63bfd738 | 511 | perf_event_mmap(vma); |
1da177e4 LT |
512 | return 0; |
513 | ||
514 | fail: | |
515 | vm_unacct_memory(charged); | |
516 | return error; | |
517 | } | |
518 | ||
7d06d9c9 DH |
519 | /* |
520 | * pkey==-1 when doing a legacy mprotect() | |
521 | */ | |
522 | static int do_mprotect_pkey(unsigned long start, size_t len, | |
523 | unsigned long prot, int pkey) | |
1da177e4 | 524 | { |
62b5f7d0 | 525 | unsigned long nstart, end, tmp, reqprot; |
1da177e4 LT |
526 | struct vm_area_struct *vma, *prev; |
527 | int error = -EINVAL; | |
528 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); | |
f138556d PK |
529 | const bool rier = (current->personality & READ_IMPLIES_EXEC) && |
530 | (prot & PROT_READ); | |
531 | ||
057d3389 AK |
532 | start = untagged_addr(start); |
533 | ||
1da177e4 LT |
534 | prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); |
535 | if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ | |
536 | return -EINVAL; | |
537 | ||
538 | if (start & ~PAGE_MASK) | |
539 | return -EINVAL; | |
540 | if (!len) | |
541 | return 0; | |
542 | len = PAGE_ALIGN(len); | |
543 | end = start + len; | |
544 | if (end <= start) | |
545 | return -ENOMEM; | |
9035cf9a | 546 | if (!arch_validate_prot(prot, start)) |
1da177e4 LT |
547 | return -EINVAL; |
548 | ||
549 | reqprot = prot; | |
1da177e4 | 550 | |
d8ed45c5 | 551 | if (mmap_write_lock_killable(current->mm)) |
dc0ef0df | 552 | return -EINTR; |
1da177e4 | 553 | |
e8c24d3a DH |
554 | /* |
555 | * If userspace did not allocate the pkey, do not let | |
556 | * them use it here. | |
557 | */ | |
558 | error = -EINVAL; | |
559 | if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey)) | |
560 | goto out; | |
561 | ||
097d5910 | 562 | vma = find_vma(current->mm, start); |
1da177e4 LT |
563 | error = -ENOMEM; |
564 | if (!vma) | |
565 | goto out; | |
097d5910 | 566 | prev = vma->vm_prev; |
1da177e4 LT |
567 | if (unlikely(grows & PROT_GROWSDOWN)) { |
568 | if (vma->vm_start >= end) | |
569 | goto out; | |
570 | start = vma->vm_start; | |
571 | error = -EINVAL; | |
572 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
573 | goto out; | |
7d12efae | 574 | } else { |
1da177e4 LT |
575 | if (vma->vm_start > start) |
576 | goto out; | |
577 | if (unlikely(grows & PROT_GROWSUP)) { | |
578 | end = vma->vm_end; | |
579 | error = -EINVAL; | |
580 | if (!(vma->vm_flags & VM_GROWSUP)) | |
581 | goto out; | |
582 | } | |
583 | } | |
584 | if (start > vma->vm_start) | |
585 | prev = vma; | |
586 | ||
587 | for (nstart = start ; ; ) { | |
a8502b67 | 588 | unsigned long mask_off_old_flags; |
1da177e4 | 589 | unsigned long newflags; |
7d06d9c9 | 590 | int new_vma_pkey; |
1da177e4 | 591 | |
7d12efae | 592 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
1da177e4 | 593 | |
f138556d PK |
594 | /* Does the application expect PROT_READ to imply PROT_EXEC */ |
595 | if (rier && (vma->vm_flags & VM_MAYEXEC)) | |
596 | prot |= PROT_EXEC; | |
597 | ||
a8502b67 DH |
598 | /* |
599 | * Each mprotect() call explicitly passes r/w/x permissions. | |
600 | * If a permission is not passed to mprotect(), it must be | |
601 | * cleared from the VMA. | |
602 | */ | |
603 | mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC | | |
2c2d57b5 | 604 | VM_FLAGS_CLEAR; |
a8502b67 | 605 | |
7d06d9c9 DH |
606 | new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); |
607 | newflags = calc_vm_prot_bits(prot, new_vma_pkey); | |
a8502b67 | 608 | newflags |= (vma->vm_flags & ~mask_off_old_flags); |
1da177e4 | 609 | |
7e2cff42 | 610 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
6cb4d9a2 | 611 | if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) { |
1da177e4 LT |
612 | error = -EACCES; |
613 | goto out; | |
614 | } | |
615 | ||
c462ac28 CM |
616 | /* Allow architectures to sanity-check the new flags */ |
617 | if (!arch_validate_flags(newflags)) { | |
618 | error = -EINVAL; | |
619 | goto out; | |
620 | } | |
621 | ||
1da177e4 LT |
622 | error = security_file_mprotect(vma, reqprot, prot); |
623 | if (error) | |
624 | goto out; | |
625 | ||
626 | tmp = vma->vm_end; | |
627 | if (tmp > end) | |
628 | tmp = end; | |
95bb7c42 | 629 | |
dbf53f75 | 630 | if (vma->vm_ops && vma->vm_ops->mprotect) { |
95bb7c42 | 631 | error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags); |
dbf53f75 TZ |
632 | if (error) |
633 | goto out; | |
634 | } | |
95bb7c42 | 635 | |
1da177e4 LT |
636 | error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); |
637 | if (error) | |
638 | goto out; | |
95bb7c42 | 639 | |
1da177e4 LT |
640 | nstart = tmp; |
641 | ||
642 | if (nstart < prev->vm_end) | |
643 | nstart = prev->vm_end; | |
644 | if (nstart >= end) | |
645 | goto out; | |
646 | ||
647 | vma = prev->vm_next; | |
648 | if (!vma || vma->vm_start != nstart) { | |
649 | error = -ENOMEM; | |
650 | goto out; | |
651 | } | |
f138556d | 652 | prot = reqprot; |
1da177e4 LT |
653 | } |
654 | out: | |
d8ed45c5 | 655 | mmap_write_unlock(current->mm); |
1da177e4 LT |
656 | return error; |
657 | } | |
7d06d9c9 DH |
658 | |
659 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, | |
660 | unsigned long, prot) | |
661 | { | |
662 | return do_mprotect_pkey(start, len, prot, -1); | |
663 | } | |
664 | ||
c7142aea HC |
665 | #ifdef CONFIG_ARCH_HAS_PKEYS |
666 | ||
7d06d9c9 DH |
667 | SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, |
668 | unsigned long, prot, int, pkey) | |
669 | { | |
670 | return do_mprotect_pkey(start, len, prot, pkey); | |
671 | } | |
e8c24d3a DH |
672 | |
673 | SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) | |
674 | { | |
675 | int pkey; | |
676 | int ret; | |
677 | ||
678 | /* No flags supported yet. */ | |
679 | if (flags) | |
680 | return -EINVAL; | |
681 | /* check for unsupported init values */ | |
682 | if (init_val & ~PKEY_ACCESS_MASK) | |
683 | return -EINVAL; | |
684 | ||
d8ed45c5 | 685 | mmap_write_lock(current->mm); |
e8c24d3a DH |
686 | pkey = mm_pkey_alloc(current->mm); |
687 | ||
688 | ret = -ENOSPC; | |
689 | if (pkey == -1) | |
690 | goto out; | |
691 | ||
692 | ret = arch_set_user_pkey_access(current, pkey, init_val); | |
693 | if (ret) { | |
694 | mm_pkey_free(current->mm, pkey); | |
695 | goto out; | |
696 | } | |
697 | ret = pkey; | |
698 | out: | |
d8ed45c5 | 699 | mmap_write_unlock(current->mm); |
e8c24d3a DH |
700 | return ret; |
701 | } | |
702 | ||
703 | SYSCALL_DEFINE1(pkey_free, int, pkey) | |
704 | { | |
705 | int ret; | |
706 | ||
d8ed45c5 | 707 | mmap_write_lock(current->mm); |
e8c24d3a | 708 | ret = mm_pkey_free(current->mm, pkey); |
d8ed45c5 | 709 | mmap_write_unlock(current->mm); |
e8c24d3a DH |
710 | |
711 | /* | |
f0953a1b | 712 | * We could provide warnings or errors if any VMA still |
e8c24d3a DH |
713 | * has the pkey set here. |
714 | */ | |
715 | return ret; | |
716 | } | |
c7142aea HC |
717 | |
718 | #endif /* CONFIG_ARCH_HAS_PKEYS */ |