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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 | ||
12 | #include <linux/mm.h> | |
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> |
1da177e4 LT |
30 | #include <asm/pgtable.h> |
31 | #include <asm/cacheflush.h> | |
e8c24d3a | 32 | #include <asm/mmu_context.h> |
1da177e4 LT |
33 | #include <asm/tlbflush.h> |
34 | ||
36f88188 KS |
35 | #include "internal.h" |
36 | ||
4b10e7d5 | 37 | static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
c1e6098b | 38 | unsigned long addr, unsigned long end, pgprot_t newprot, |
0f19c179 | 39 | int dirty_accountable, int prot_numa) |
1da177e4 | 40 | { |
4b10e7d5 | 41 | struct mm_struct *mm = vma->vm_mm; |
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 | ||
83 | page = vm_normal_page(vma, addr, oldpte); | |
84 | if (!page || PageKsm(page)) | |
85 | continue; | |
10c1045f MG |
86 | |
87 | /* Avoid TLB flush if possible */ | |
88 | if (pte_protnone(oldpte)) | |
89 | continue; | |
3e321587 AK |
90 | |
91 | /* | |
92 | * Don't mess with PTEs if page is already on the node | |
93 | * a single-threaded process is running on. | |
94 | */ | |
95 | if (target_node == page_to_nid(page)) | |
96 | continue; | |
e944fd67 MG |
97 | } |
98 | ||
8a0516ed MG |
99 | ptent = ptep_modify_prot_start(mm, addr, pte); |
100 | ptent = pte_modify(ptent, newprot); | |
b191f9b1 | 101 | if (preserve_write) |
288bc549 | 102 | ptent = pte_mk_savedwrite(ptent); |
4b10e7d5 | 103 | |
8a0516ed MG |
104 | /* Avoid taking write faults for known dirty pages */ |
105 | if (dirty_accountable && pte_dirty(ptent) && | |
106 | (pte_soft_dirty(ptent) || | |
107 | !(vma->vm_flags & VM_SOFTDIRTY))) { | |
108 | ptent = pte_mkwrite(ptent); | |
4b10e7d5 | 109 | } |
8a0516ed MG |
110 | ptep_modify_prot_commit(mm, addr, pte, ptent); |
111 | pages++; | |
0661a336 | 112 | } else if (IS_ENABLED(CONFIG_MIGRATION)) { |
0697212a CL |
113 | swp_entry_t entry = pte_to_swp_entry(oldpte); |
114 | ||
115 | if (is_write_migration_entry(entry)) { | |
c3d16e16 | 116 | pte_t newpte; |
0697212a CL |
117 | /* |
118 | * A protection check is difficult so | |
119 | * just be safe and disable write | |
120 | */ | |
121 | make_migration_entry_read(&entry); | |
c3d16e16 CG |
122 | newpte = swp_entry_to_pte(entry); |
123 | if (pte_swp_soft_dirty(oldpte)) | |
124 | newpte = pte_swp_mksoft_dirty(newpte); | |
125 | set_pte_at(mm, addr, pte, newpte); | |
e920e14c MG |
126 | |
127 | pages++; | |
0697212a | 128 | } |
5042db43 JG |
129 | |
130 | if (is_write_device_private_entry(entry)) { | |
131 | pte_t newpte; | |
132 | ||
133 | /* | |
134 | * We do not preserve soft-dirtiness. See | |
135 | * copy_one_pte() for explanation. | |
136 | */ | |
137 | make_device_private_entry_read(&entry); | |
138 | newpte = swp_entry_to_pte(entry); | |
139 | set_pte_at(mm, addr, pte, newpte); | |
140 | ||
141 | pages++; | |
142 | } | |
1da177e4 LT |
143 | } |
144 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 145 | arch_leave_lazy_mmu_mode(); |
705e87c0 | 146 | pte_unmap_unlock(pte - 1, ptl); |
7da4d641 PZ |
147 | |
148 | return pages; | |
1da177e4 LT |
149 | } |
150 | ||
7d12efae AM |
151 | static inline unsigned long change_pmd_range(struct vm_area_struct *vma, |
152 | pud_t *pud, unsigned long addr, unsigned long end, | |
153 | pgprot_t newprot, int dirty_accountable, int prot_numa) | |
1da177e4 LT |
154 | { |
155 | pmd_t *pmd; | |
a5338093 | 156 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 157 | unsigned long next; |
7da4d641 | 158 | unsigned long pages = 0; |
72403b4a | 159 | unsigned long nr_huge_updates = 0; |
a5338093 | 160 | unsigned long mni_start = 0; |
1da177e4 LT |
161 | |
162 | pmd = pmd_offset(pud, addr); | |
163 | do { | |
25cbbef1 MG |
164 | unsigned long this_pages; |
165 | ||
1da177e4 | 166 | next = pmd_addr_end(addr, end); |
84c3fc4e | 167 | if (!is_swap_pmd(*pmd) && !pmd_trans_huge(*pmd) && !pmd_devmap(*pmd) |
5c7fb56e | 168 | && pmd_none_or_clear_bad(pmd)) |
4991c09c | 169 | goto next; |
a5338093 RR |
170 | |
171 | /* invoke the mmu notifier if the pmd is populated */ | |
172 | if (!mni_start) { | |
173 | mni_start = addr; | |
174 | mmu_notifier_invalidate_range_start(mm, mni_start, end); | |
175 | } | |
176 | ||
84c3fc4e | 177 | if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { |
6b9116a6 | 178 | if (next - addr != HPAGE_PMD_SIZE) { |
fd60775a | 179 | __split_huge_pmd(vma, pmd, addr, false, NULL); |
6b9116a6 | 180 | } else { |
f123d74a | 181 | int nr_ptes = change_huge_pmd(vma, pmd, addr, |
e944fd67 | 182 | newprot, prot_numa); |
f123d74a MG |
183 | |
184 | if (nr_ptes) { | |
72403b4a MG |
185 | if (nr_ptes == HPAGE_PMD_NR) { |
186 | pages += HPAGE_PMD_NR; | |
187 | nr_huge_updates++; | |
188 | } | |
1ad9f620 MG |
189 | |
190 | /* huge pmd was handled */ | |
4991c09c | 191 | goto next; |
f123d74a | 192 | } |
7da4d641 | 193 | } |
88a9ab6e | 194 | /* fall through, the trans huge pmd just split */ |
cd7548ab | 195 | } |
25cbbef1 | 196 | this_pages = change_pte_range(vma, pmd, addr, next, newprot, |
0f19c179 | 197 | dirty_accountable, prot_numa); |
25cbbef1 | 198 | pages += this_pages; |
4991c09c AK |
199 | next: |
200 | cond_resched(); | |
1da177e4 | 201 | } while (pmd++, addr = next, addr != end); |
7da4d641 | 202 | |
a5338093 RR |
203 | if (mni_start) |
204 | mmu_notifier_invalidate_range_end(mm, mni_start, end); | |
205 | ||
72403b4a MG |
206 | if (nr_huge_updates) |
207 | count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); | |
7da4d641 | 208 | return pages; |
1da177e4 LT |
209 | } |
210 | ||
7d12efae | 211 | static inline unsigned long change_pud_range(struct vm_area_struct *vma, |
c2febafc | 212 | p4d_t *p4d, unsigned long addr, unsigned long end, |
7d12efae | 213 | pgprot_t newprot, int dirty_accountable, int prot_numa) |
1da177e4 LT |
214 | { |
215 | pud_t *pud; | |
216 | unsigned long next; | |
7da4d641 | 217 | unsigned long pages = 0; |
1da177e4 | 218 | |
c2febafc | 219 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
220 | do { |
221 | next = pud_addr_end(addr, end); | |
222 | if (pud_none_or_clear_bad(pud)) | |
223 | continue; | |
7da4d641 | 224 | pages += change_pmd_range(vma, pud, addr, next, newprot, |
4b10e7d5 | 225 | dirty_accountable, prot_numa); |
1da177e4 | 226 | } while (pud++, addr = next, addr != end); |
7da4d641 PZ |
227 | |
228 | return pages; | |
1da177e4 LT |
229 | } |
230 | ||
c2febafc KS |
231 | static inline unsigned long change_p4d_range(struct vm_area_struct *vma, |
232 | pgd_t *pgd, unsigned long addr, unsigned long end, | |
233 | pgprot_t newprot, int dirty_accountable, int prot_numa) | |
234 | { | |
235 | p4d_t *p4d; | |
236 | unsigned long next; | |
237 | unsigned long pages = 0; | |
238 | ||
239 | p4d = p4d_offset(pgd, addr); | |
240 | do { | |
241 | next = p4d_addr_end(addr, end); | |
242 | if (p4d_none_or_clear_bad(p4d)) | |
243 | continue; | |
244 | pages += change_pud_range(vma, p4d, addr, next, newprot, | |
245 | dirty_accountable, prot_numa); | |
246 | } while (p4d++, addr = next, addr != end); | |
247 | ||
248 | return pages; | |
249 | } | |
250 | ||
7da4d641 | 251 | static unsigned long change_protection_range(struct vm_area_struct *vma, |
c1e6098b | 252 | unsigned long addr, unsigned long end, pgprot_t newprot, |
4b10e7d5 | 253 | int dirty_accountable, int prot_numa) |
1da177e4 LT |
254 | { |
255 | struct mm_struct *mm = vma->vm_mm; | |
256 | pgd_t *pgd; | |
257 | unsigned long next; | |
258 | unsigned long start = addr; | |
7da4d641 | 259 | unsigned long pages = 0; |
1da177e4 LT |
260 | |
261 | BUG_ON(addr >= end); | |
262 | pgd = pgd_offset(mm, addr); | |
263 | flush_cache_range(vma, addr, end); | |
16af97dc | 264 | inc_tlb_flush_pending(mm); |
1da177e4 LT |
265 | do { |
266 | next = pgd_addr_end(addr, end); | |
267 | if (pgd_none_or_clear_bad(pgd)) | |
268 | continue; | |
c2febafc | 269 | pages += change_p4d_range(vma, pgd, addr, next, newprot, |
4b10e7d5 | 270 | dirty_accountable, prot_numa); |
1da177e4 | 271 | } while (pgd++, addr = next, addr != end); |
7da4d641 | 272 | |
1233d588 IM |
273 | /* Only flush the TLB if we actually modified any entries: */ |
274 | if (pages) | |
275 | flush_tlb_range(vma, start, end); | |
16af97dc | 276 | dec_tlb_flush_pending(mm); |
7da4d641 PZ |
277 | |
278 | return pages; | |
279 | } | |
280 | ||
281 | unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, | |
282 | unsigned long end, pgprot_t newprot, | |
4b10e7d5 | 283 | int dirty_accountable, int prot_numa) |
7da4d641 | 284 | { |
7da4d641 PZ |
285 | unsigned long pages; |
286 | ||
7da4d641 PZ |
287 | if (is_vm_hugetlb_page(vma)) |
288 | pages = hugetlb_change_protection(vma, start, end, newprot); | |
289 | else | |
4b10e7d5 | 290 | pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa); |
7da4d641 PZ |
291 | |
292 | return pages; | |
1da177e4 LT |
293 | } |
294 | ||
0831b2a2 AK |
295 | static int prot_none_pte_entry(pte_t *pte, unsigned long addr, |
296 | unsigned long next, struct mm_walk *walk) | |
297 | { | |
298 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
299 | 0 : -EACCES; | |
300 | } | |
301 | ||
302 | static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, | |
303 | unsigned long addr, unsigned long next, | |
304 | struct mm_walk *walk) | |
305 | { | |
306 | return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? | |
307 | 0 : -EACCES; | |
308 | } | |
309 | ||
310 | static int prot_none_test(unsigned long addr, unsigned long next, | |
311 | struct mm_walk *walk) | |
312 | { | |
313 | return 0; | |
314 | } | |
315 | ||
316 | static int prot_none_walk(struct vm_area_struct *vma, unsigned long start, | |
317 | unsigned long end, unsigned long newflags) | |
318 | { | |
319 | pgprot_t new_pgprot = vm_get_page_prot(newflags); | |
320 | struct mm_walk prot_none_walk = { | |
321 | .pte_entry = prot_none_pte_entry, | |
322 | .hugetlb_entry = prot_none_hugetlb_entry, | |
323 | .test_walk = prot_none_test, | |
324 | .mm = current->mm, | |
325 | .private = &new_pgprot, | |
326 | }; | |
327 | ||
328 | return walk_page_range(start, end, &prot_none_walk); | |
329 | } | |
330 | ||
b6a2fea3 | 331 | int |
1da177e4 LT |
332 | mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, |
333 | unsigned long start, unsigned long end, unsigned long newflags) | |
334 | { | |
335 | struct mm_struct *mm = vma->vm_mm; | |
336 | unsigned long oldflags = vma->vm_flags; | |
337 | long nrpages = (end - start) >> PAGE_SHIFT; | |
338 | unsigned long charged = 0; | |
1da177e4 LT |
339 | pgoff_t pgoff; |
340 | int error; | |
c1e6098b | 341 | int dirty_accountable = 0; |
1da177e4 LT |
342 | |
343 | if (newflags == oldflags) { | |
344 | *pprev = vma; | |
345 | return 0; | |
346 | } | |
347 | ||
0831b2a2 AK |
348 | /* |
349 | * Do PROT_NONE PFN permission checks here when we can still | |
350 | * bail out without undoing a lot of state. This is a rather | |
351 | * uncommon case, so doesn't need to be very optimized. | |
352 | */ | |
353 | if (arch_has_pfn_modify_check() && | |
354 | (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && | |
355 | (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) { | |
356 | error = prot_none_walk(vma, start, end, newflags); | |
357 | if (error) | |
358 | return error; | |
359 | } | |
360 | ||
1da177e4 LT |
361 | /* |
362 | * If we make a private mapping writable we increase our commit; | |
363 | * but (without finer accounting) cannot reduce our commit if we | |
5a6fe125 MG |
364 | * make it unwritable again. hugetlb mapping were accounted for |
365 | * even if read-only so there is no need to account for them here | |
1da177e4 LT |
366 | */ |
367 | if (newflags & VM_WRITE) { | |
84638335 KK |
368 | /* Check space limits when area turns into data. */ |
369 | if (!may_expand_vm(mm, newflags, nrpages) && | |
370 | may_expand_vm(mm, oldflags, nrpages)) | |
371 | return -ENOMEM; | |
5a6fe125 | 372 | if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| |
cdfd4325 | 373 | VM_SHARED|VM_NORESERVE))) { |
1da177e4 | 374 | charged = nrpages; |
191c5424 | 375 | if (security_vm_enough_memory_mm(mm, charged)) |
1da177e4 LT |
376 | return -ENOMEM; |
377 | newflags |= VM_ACCOUNT; | |
378 | } | |
379 | } | |
380 | ||
1da177e4 LT |
381 | /* |
382 | * First try to merge with previous and/or next vma. | |
383 | */ | |
384 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
385 | *pprev = vma_merge(mm, *pprev, start, end, newflags, | |
19a809af AA |
386 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), |
387 | vma->vm_userfaultfd_ctx); | |
1da177e4 LT |
388 | if (*pprev) { |
389 | vma = *pprev; | |
e86f15ee | 390 | VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY); |
1da177e4 LT |
391 | goto success; |
392 | } | |
393 | ||
394 | *pprev = vma; | |
395 | ||
396 | if (start != vma->vm_start) { | |
397 | error = split_vma(mm, vma, start, 1); | |
398 | if (error) | |
399 | goto fail; | |
400 | } | |
401 | ||
402 | if (end != vma->vm_end) { | |
403 | error = split_vma(mm, vma, end, 0); | |
404 | if (error) | |
405 | goto fail; | |
406 | } | |
407 | ||
408 | success: | |
409 | /* | |
410 | * vm_flags and vm_page_prot are protected by the mmap_sem | |
411 | * held in write mode. | |
412 | */ | |
413 | vma->vm_flags = newflags; | |
6d2329f8 | 414 | dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot); |
64e45507 | 415 | vma_set_page_prot(vma); |
d08b3851 | 416 | |
7d12efae AM |
417 | change_protection(vma, start, end, vma->vm_page_prot, |
418 | dirty_accountable, 0); | |
7da4d641 | 419 | |
36f88188 KS |
420 | /* |
421 | * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major | |
422 | * fault on access. | |
423 | */ | |
424 | if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED && | |
425 | (newflags & VM_WRITE)) { | |
426 | populate_vma_page_range(vma, start, end, NULL); | |
427 | } | |
428 | ||
84638335 KK |
429 | vm_stat_account(mm, oldflags, -nrpages); |
430 | vm_stat_account(mm, newflags, nrpages); | |
63bfd738 | 431 | perf_event_mmap(vma); |
1da177e4 LT |
432 | return 0; |
433 | ||
434 | fail: | |
435 | vm_unacct_memory(charged); | |
436 | return error; | |
437 | } | |
438 | ||
7d06d9c9 DH |
439 | /* |
440 | * pkey==-1 when doing a legacy mprotect() | |
441 | */ | |
442 | static int do_mprotect_pkey(unsigned long start, size_t len, | |
443 | unsigned long prot, int pkey) | |
1da177e4 | 444 | { |
62b5f7d0 | 445 | unsigned long nstart, end, tmp, reqprot; |
1da177e4 LT |
446 | struct vm_area_struct *vma, *prev; |
447 | int error = -EINVAL; | |
448 | const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); | |
f138556d PK |
449 | const bool rier = (current->personality & READ_IMPLIES_EXEC) && |
450 | (prot & PROT_READ); | |
451 | ||
1da177e4 LT |
452 | prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); |
453 | if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ | |
454 | return -EINVAL; | |
455 | ||
456 | if (start & ~PAGE_MASK) | |
457 | return -EINVAL; | |
458 | if (!len) | |
459 | return 0; | |
460 | len = PAGE_ALIGN(len); | |
461 | end = start + len; | |
462 | if (end <= start) | |
463 | return -ENOMEM; | |
b845f313 | 464 | if (!arch_validate_prot(prot)) |
1da177e4 LT |
465 | return -EINVAL; |
466 | ||
467 | reqprot = prot; | |
1da177e4 | 468 | |
dc0ef0df MH |
469 | if (down_write_killable(¤t->mm->mmap_sem)) |
470 | return -EINTR; | |
1da177e4 | 471 | |
e8c24d3a DH |
472 | /* |
473 | * If userspace did not allocate the pkey, do not let | |
474 | * them use it here. | |
475 | */ | |
476 | error = -EINVAL; | |
477 | if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey)) | |
478 | goto out; | |
479 | ||
097d5910 | 480 | vma = find_vma(current->mm, start); |
1da177e4 LT |
481 | error = -ENOMEM; |
482 | if (!vma) | |
483 | goto out; | |
097d5910 | 484 | prev = vma->vm_prev; |
1da177e4 LT |
485 | if (unlikely(grows & PROT_GROWSDOWN)) { |
486 | if (vma->vm_start >= end) | |
487 | goto out; | |
488 | start = vma->vm_start; | |
489 | error = -EINVAL; | |
490 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
491 | goto out; | |
7d12efae | 492 | } else { |
1da177e4 LT |
493 | if (vma->vm_start > start) |
494 | goto out; | |
495 | if (unlikely(grows & PROT_GROWSUP)) { | |
496 | end = vma->vm_end; | |
497 | error = -EINVAL; | |
498 | if (!(vma->vm_flags & VM_GROWSUP)) | |
499 | goto out; | |
500 | } | |
501 | } | |
502 | if (start > vma->vm_start) | |
503 | prev = vma; | |
504 | ||
505 | for (nstart = start ; ; ) { | |
a8502b67 | 506 | unsigned long mask_off_old_flags; |
1da177e4 | 507 | unsigned long newflags; |
7d06d9c9 | 508 | int new_vma_pkey; |
1da177e4 | 509 | |
7d12efae | 510 | /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
1da177e4 | 511 | |
f138556d PK |
512 | /* Does the application expect PROT_READ to imply PROT_EXEC */ |
513 | if (rier && (vma->vm_flags & VM_MAYEXEC)) | |
514 | prot |= PROT_EXEC; | |
515 | ||
a8502b67 DH |
516 | /* |
517 | * Each mprotect() call explicitly passes r/w/x permissions. | |
518 | * If a permission is not passed to mprotect(), it must be | |
519 | * cleared from the VMA. | |
520 | */ | |
521 | mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC | | |
522 | ARCH_VM_PKEY_FLAGS; | |
523 | ||
7d06d9c9 DH |
524 | new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); |
525 | newflags = calc_vm_prot_bits(prot, new_vma_pkey); | |
a8502b67 | 526 | newflags |= (vma->vm_flags & ~mask_off_old_flags); |
1da177e4 | 527 | |
7e2cff42 PBG |
528 | /* newflags >> 4 shift VM_MAY% in place of VM_% */ |
529 | if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) { | |
1da177e4 LT |
530 | error = -EACCES; |
531 | goto out; | |
532 | } | |
533 | ||
534 | error = security_file_mprotect(vma, reqprot, prot); | |
535 | if (error) | |
536 | goto out; | |
537 | ||
538 | tmp = vma->vm_end; | |
539 | if (tmp > end) | |
540 | tmp = end; | |
541 | error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); | |
542 | if (error) | |
543 | goto out; | |
544 | nstart = tmp; | |
545 | ||
546 | if (nstart < prev->vm_end) | |
547 | nstart = prev->vm_end; | |
548 | if (nstart >= end) | |
549 | goto out; | |
550 | ||
551 | vma = prev->vm_next; | |
552 | if (!vma || vma->vm_start != nstart) { | |
553 | error = -ENOMEM; | |
554 | goto out; | |
555 | } | |
f138556d | 556 | prot = reqprot; |
1da177e4 LT |
557 | } |
558 | out: | |
559 | up_write(¤t->mm->mmap_sem); | |
560 | return error; | |
561 | } | |
7d06d9c9 DH |
562 | |
563 | SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, | |
564 | unsigned long, prot) | |
565 | { | |
566 | return do_mprotect_pkey(start, len, prot, -1); | |
567 | } | |
568 | ||
c7142aea HC |
569 | #ifdef CONFIG_ARCH_HAS_PKEYS |
570 | ||
7d06d9c9 DH |
571 | SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, |
572 | unsigned long, prot, int, pkey) | |
573 | { | |
574 | return do_mprotect_pkey(start, len, prot, pkey); | |
575 | } | |
e8c24d3a DH |
576 | |
577 | SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) | |
578 | { | |
579 | int pkey; | |
580 | int ret; | |
581 | ||
582 | /* No flags supported yet. */ | |
583 | if (flags) | |
584 | return -EINVAL; | |
585 | /* check for unsupported init values */ | |
586 | if (init_val & ~PKEY_ACCESS_MASK) | |
587 | return -EINVAL; | |
588 | ||
589 | down_write(¤t->mm->mmap_sem); | |
590 | pkey = mm_pkey_alloc(current->mm); | |
591 | ||
592 | ret = -ENOSPC; | |
593 | if (pkey == -1) | |
594 | goto out; | |
595 | ||
596 | ret = arch_set_user_pkey_access(current, pkey, init_val); | |
597 | if (ret) { | |
598 | mm_pkey_free(current->mm, pkey); | |
599 | goto out; | |
600 | } | |
601 | ret = pkey; | |
602 | out: | |
603 | up_write(¤t->mm->mmap_sem); | |
604 | return ret; | |
605 | } | |
606 | ||
607 | SYSCALL_DEFINE1(pkey_free, int, pkey) | |
608 | { | |
609 | int ret; | |
610 | ||
611 | down_write(¤t->mm->mmap_sem); | |
612 | ret = mm_pkey_free(current->mm, pkey); | |
613 | up_write(¤t->mm->mmap_sem); | |
614 | ||
615 | /* | |
616 | * We could provie warnings or errors if any VMA still | |
617 | * has the pkey set here. | |
618 | */ | |
619 | return ret; | |
620 | } | |
c7142aea HC |
621 | |
622 | #endif /* CONFIG_ARCH_HAS_PKEYS */ |