mm/mprotect.c

   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 <linux/sched/sysctl.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/mmu_context.h>
  35 #include <asm/tlbflush.h>
  36
  37 #include "internal.h"
  38
  39 static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
  40                 unsigned long addr, unsigned long end, pgprot_t newprot,
  41                 unsigned long cp_flags)
  42 {
  43         pte_t *pte, oldpte;
  44         spinlock_t *ptl;
  45         unsigned long pages = 0;
  46         int target_node = NUMA_NO_NODE;
  47         bool dirty_accountable = cp_flags & MM_CP_DIRTY_ACCT;
  48         bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
  49         bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
  50         bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
  51
  52         /*
  53          * Can be called with only the mmap_lock for reading by
  54          * prot_numa so we must check the pmd isn't constantly
  55          * changing from under us from pmd_none to pmd_trans_huge
  56          * and/or the other way around.
  57          */
  58         if (pmd_trans_unstable(pmd))
  59                 return 0;
  60
  61         /*
  62          * The pmd points to a regular pte so the pmd can't change
  63          * from under us even if the mmap_lock is only hold for
  64          * reading.
  65          */
  66         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
  67
  68         /* Get target node for single threaded private VMAs */
  69         if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
  70             atomic_read(&vma->vm_mm->mm_users) == 1)
  71                 target_node = numa_node_id();
  72
  73         flush_tlb_batched_pending(vma->vm_mm);
  74         arch_enter_lazy_mmu_mode();
  75         do {
  76                 oldpte = *pte;
  77                 if (pte_present(oldpte)) {
  78                         pte_t ptent;
  79                         bool preserve_write = prot_numa && pte_write(oldpte);
  80
  81                         /*
  82                          * Avoid trapping faults against the zero or KSM
  83                          * pages. See similar comment in change_huge_pmd.
  84                          */
  85                         if (prot_numa) {
  86                                 struct page *page;
  87                                 int nid;
  88
  89                                 /* Avoid TLB flush if possible */
  90                                 if (pte_protnone(oldpte))
  91                                         continue;
  92
  93                                 page = vm_normal_page(vma, addr, oldpte);
  94                                 if (!page || PageKsm(page))
  95                                         continue;
  96
  97                                 /* Also skip shared copy-on-write pages */
  98                                 if (is_cow_mapping(vma->vm_flags) &&
  99                                     page_count(page) != 1)
 100                                         continue;
 101
 102                                 /*
 103                                  * While migration can move some dirty pages,
 104                                  * it cannot move them all from MIGRATE_ASYNC
 105                                  * context.
 106                                  */
 107                                 if (page_is_file_lru(page) && PageDirty(page))
 108                                         continue;
 109
 110                                 /*
 111                                  * Don't mess with PTEs if page is already on the node
 112                                  * a single-threaded process is running on.
 113                                  */
 114                                 nid = page_to_nid(page);
 115                                 if (target_node == nid)
 116                                         continue;
 117
 118                                 /*
 119                                  * Skip scanning top tier node if normal numa
 120                                  * balancing is disabled
 121                                  */
 122                                 if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
 123                                     node_is_toptier(nid))
 124                                         continue;
 125                         }
 126
 127                         oldpte = ptep_modify_prot_start(vma, addr, pte);
 128                         ptent = pte_modify(oldpte, newprot);
 129                         if (preserve_write)
 130                                 ptent = pte_mk_savedwrite(ptent);
 131
 132                         if (uffd_wp) {
 133                                 ptent = pte_wrprotect(ptent);
 134                                 ptent = pte_mkuffd_wp(ptent);
 135                         } else if (uffd_wp_resolve) {
 136                                 /*
 137                                  * Leave the write bit to be handled
 138                                  * by PF interrupt handler, then
 139                                  * things like COW could be properly
 140                                  * handled.
 141                                  */
 142                                 ptent = pte_clear_uffd_wp(ptent);
 143                         }
 144
 145                         /* Avoid taking write faults for known dirty pages */
 146                         if (dirty_accountable && pte_dirty(ptent) &&
 147                                         (pte_soft_dirty(ptent) ||
 148                                          !(vma->vm_flags & VM_SOFTDIRTY))) {
 149                                 ptent = pte_mkwrite(ptent);
 150                         }
 151                         ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
 152                         pages++;
 153                 } else if (is_swap_pte(oldpte)) {
 154                         swp_entry_t entry = pte_to_swp_entry(oldpte);
 155                         pte_t newpte;
 156
 157                         if (is_writable_migration_entry(entry)) {
 158                                 /*
 159                                  * A protection check is difficult so
 160                                  * just be safe and disable write
 161                                  */
 162                                 entry = make_readable_migration_entry(
 163                                                         swp_offset(entry));
 164                                 newpte = swp_entry_to_pte(entry);
 165                                 if (pte_swp_soft_dirty(oldpte))
 166                                         newpte = pte_swp_mksoft_dirty(newpte);
 167                                 if (pte_swp_uffd_wp(oldpte))
 168                                         newpte = pte_swp_mkuffd_wp(newpte);
 169                         } else if (is_writable_device_private_entry(entry)) {
 170                                 /*
 171                                  * We do not preserve soft-dirtiness. See
 172                                  * copy_one_pte() for explanation.
 173                                  */
 174                                 entry = make_readable_device_private_entry(
 175                                                         swp_offset(entry));
 176                                 newpte = swp_entry_to_pte(entry);
 177                                 if (pte_swp_uffd_wp(oldpte))
 178                                         newpte = pte_swp_mkuffd_wp(newpte);
 179                         } else if (is_writable_device_exclusive_entry(entry)) {
 180                                 entry = make_readable_device_exclusive_entry(
 181                                                         swp_offset(entry));
 182                                 newpte = swp_entry_to_pte(entry);
 183                                 if (pte_swp_soft_dirty(oldpte))
 184                                         newpte = pte_swp_mksoft_dirty(newpte);
 185                                 if (pte_swp_uffd_wp(oldpte))
 186                                         newpte = pte_swp_mkuffd_wp(newpte);
 187                         } else {
 188                                 newpte = oldpte;
 189                         }
 190
 191                         if (uffd_wp)
 192                                 newpte = pte_swp_mkuffd_wp(newpte);
 193                         else if (uffd_wp_resolve)
 194                                 newpte = pte_swp_clear_uffd_wp(newpte);
 195
 196                         if (!pte_same(oldpte, newpte)) {
 197                                 set_pte_at(vma->vm_mm, addr, pte, newpte);
 198                                 pages++;
 199                         }
 200                 }
 201         } while (pte++, addr += PAGE_SIZE, addr != end);
 202         arch_leave_lazy_mmu_mode();
 203         pte_unmap_unlock(pte - 1, ptl);
 204
 205         return pages;
 206 }
 207
 208 /*
 209  * Used when setting automatic NUMA hinting protection where it is
 210  * critical that a numa hinting PMD is not confused with a bad PMD.
 211  */
 212 static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd)
 213 {
 214         pmd_t pmdval = pmd_read_atomic(pmd);
 215
 216         /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */
 217 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 218         barrier();
 219 #endif
 220
 221         if (pmd_none(pmdval))
 222                 return 1;
 223         if (pmd_trans_huge(pmdval))
 224                 return 0;
 225         if (unlikely(pmd_bad(pmdval))) {
 226                 pmd_clear_bad(pmd);
 227                 return 1;
 228         }
 229
 230         return 0;
 231 }
 232
 233 static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
 234                 pud_t *pud, unsigned long addr, unsigned long end,
 235                 pgprot_t newprot, unsigned long cp_flags)
 236 {
 237         pmd_t *pmd;
 238         unsigned long next;
 239         unsigned long pages = 0;
 240         unsigned long nr_huge_updates = 0;
 241         struct mmu_notifier_range range;
 242
 243         range.start = 0;
 244
 245         pmd = pmd_offset(pud, addr);
 246         do {
 247                 unsigned long this_pages;
 248
 249                 next = pmd_addr_end(addr, end);
 250
 251                 /*
 252                  * Automatic NUMA balancing walks the tables with mmap_lock
 253                  * held for read. It's possible a parallel update to occur
 254                  * between pmd_trans_huge() and a pmd_none_or_clear_bad()
 255                  * check leading to a false positive and clearing.
 256                  * Hence, it's necessary to atomically read the PMD value
 257                  * for all the checks.
 258                  */
 259                 if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) &&
 260                      pmd_none_or_clear_bad_unless_trans_huge(pmd))
 261                         goto next;
 262
 263                 /* invoke the mmu notifier if the pmd is populated */
 264                 if (!range.start) {
 265                         mmu_notifier_range_init(&range,
 266                                 MMU_NOTIFY_PROTECTION_VMA, 0,
 267                                 vma, vma->vm_mm, addr, end);
 268                         mmu_notifier_invalidate_range_start(&range);
 269                 }
 270
 271                 if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
 272                         if (next - addr != HPAGE_PMD_SIZE) {
 273                                 __split_huge_pmd(vma, pmd, addr, false, NULL);
 274                         } else {
 275                                 int nr_ptes = change_huge_pmd(vma, pmd, addr,
 276                                                               newprot, cp_flags);
 277
 278                                 if (nr_ptes) {
 279                                         if (nr_ptes == HPAGE_PMD_NR) {
 280                                                 pages += HPAGE_PMD_NR;
 281                                                 nr_huge_updates++;
 282                                         }
 283
 284                                         /* huge pmd was handled */
 285                                         goto next;
 286                                 }
 287                         }
 288                         /* fall through, the trans huge pmd just split */
 289                 }
 290                 this_pages = change_pte_range(vma, pmd, addr, next, newprot,
 291                                               cp_flags);
 292                 pages += this_pages;
 293 next:
 294                 cond_resched();
 295         } while (pmd++, addr = next, addr != end);
 296
 297         if (range.start)
 298                 mmu_notifier_invalidate_range_end(&range);
 299
 300         if (nr_huge_updates)
 301                 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
 302         return pages;
 303 }
 304
 305 static inline unsigned long change_pud_range(struct vm_area_struct *vma,
 306                 p4d_t *p4d, unsigned long addr, unsigned long end,
 307                 pgprot_t newprot, unsigned long cp_flags)
 308 {
 309         pud_t *pud;
 310         unsigned long next;
 311         unsigned long pages = 0;
 312
 313         pud = pud_offset(p4d, addr);
 314         do {
 315                 next = pud_addr_end(addr, end);
 316                 if (pud_none_or_clear_bad(pud))
 317                         continue;
 318                 pages += change_pmd_range(vma, pud, addr, next, newprot,
 319                                           cp_flags);
 320         } while (pud++, addr = next, addr != end);
 321
 322         return pages;
 323 }
 324
 325 static inline unsigned long change_p4d_range(struct vm_area_struct *vma,
 326                 pgd_t *pgd, unsigned long addr, unsigned long end,
 327                 pgprot_t newprot, unsigned long cp_flags)
 328 {
 329         p4d_t *p4d;
 330         unsigned long next;
 331         unsigned long pages = 0;
 332
 333         p4d = p4d_offset(pgd, addr);
 334         do {
 335                 next = p4d_addr_end(addr, end);
 336                 if (p4d_none_or_clear_bad(p4d))
 337                         continue;
 338                 pages += change_pud_range(vma, p4d, addr, next, newprot,
 339                                           cp_flags);
 340         } while (p4d++, addr = next, addr != end);
 341
 342         return pages;
 343 }
 344
 345 static unsigned long change_protection_range(struct vm_area_struct *vma,
 346                 unsigned long addr, unsigned long end, pgprot_t newprot,
 347                 unsigned long cp_flags)
 348 {
 349         struct mm_struct *mm = vma->vm_mm;
 350         pgd_t *pgd;
 351         unsigned long next;
 352         unsigned long start = addr;
 353         unsigned long pages = 0;
 354
 355         BUG_ON(addr >= end);
 356         pgd = pgd_offset(mm, addr);
 357         flush_cache_range(vma, addr, end);
 358         inc_tlb_flush_pending(mm);
 359         do {
 360                 next = pgd_addr_end(addr, end);
 361                 if (pgd_none_or_clear_bad(pgd))
 362                         continue;
 363                 pages += change_p4d_range(vma, pgd, addr, next, newprot,
 364                                           cp_flags);
 365         } while (pgd++, addr = next, addr != end);
 366
 367         /* Only flush the TLB if we actually modified any entries: */
 368         if (pages)
 369                 flush_tlb_range(vma, start, end);
 370         dec_tlb_flush_pending(mm);
 371
 372         return pages;
 373 }
 374
 375 unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
 376                        unsigned long end, pgprot_t newprot,
 377                        unsigned long cp_flags)
 378 {
 379         unsigned long pages;
 380
 381         BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
 382
 383         if (is_vm_hugetlb_page(vma))
 384                 pages = hugetlb_change_protection(vma, start, end, newprot);
 385         else
 386                 pages = change_protection_range(vma, start, end, newprot,
 387                                                 cp_flags);
 388
 389         return pages;
 390 }
 391
 392 static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
 393                                unsigned long next, struct mm_walk *walk)
 394 {
 395         return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
 396                 0 : -EACCES;
 397 }
 398
 399 static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
 400                                    unsigned long addr, unsigned long next,
 401                                    struct mm_walk *walk)
 402 {
 403         return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
 404                 0 : -EACCES;
 405 }
 406
 407 static int prot_none_test(unsigned long addr, unsigned long next,
 408                           struct mm_walk *walk)
 409 {
 410         return 0;
 411 }
 412
 413 static const struct mm_walk_ops prot_none_walk_ops = {
 414         .pte_entry              = prot_none_pte_entry,
 415         .hugetlb_entry          = prot_none_hugetlb_entry,
 416         .test_walk              = prot_none_test,
 417 };
 418
 419 int
 420 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 421         unsigned long start, unsigned long end, unsigned long newflags)
 422 {
 423         struct mm_struct *mm = vma->vm_mm;
 424         unsigned long oldflags = vma->vm_flags;
 425         long nrpages = (end - start) >> PAGE_SHIFT;
 426         unsigned long charged = 0;
 427         pgoff_t pgoff;
 428         int error;
 429         int dirty_accountable = 0;
 430
 431         if (newflags == oldflags) {
 432                 *pprev = vma;
 433                 return 0;
 434         }
 435
 436         /*
 437          * Do PROT_NONE PFN permission checks here when we can still
 438          * bail out without undoing a lot of state. This is a rather
 439          * uncommon case, so doesn't need to be very optimized.
 440          */
 441         if (arch_has_pfn_modify_check() &&
 442             (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
 443             (newflags & VM_ACCESS_FLAGS) == 0) {
 444                 pgprot_t new_pgprot = vm_get_page_prot(newflags);
 445
 446                 error = walk_page_range(current->mm, start, end,
 447                                 &prot_none_walk_ops, &new_pgprot);
 448                 if (error)
 449                         return error;
 450         }
 451
 452         /*
 453          * If we make a private mapping writable we increase our commit;
 454          * but (without finer accounting) cannot reduce our commit if we
 455          * make it unwritable again. hugetlb mapping were accounted for
 456          * even if read-only so there is no need to account for them here
 457          */
 458         if (newflags & VM_WRITE) {
 459                 /* Check space limits when area turns into data. */
 460                 if (!may_expand_vm(mm, newflags, nrpages) &&
 461                                 may_expand_vm(mm, oldflags, nrpages))
 462                         return -ENOMEM;
 463                 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
 464                                                 VM_SHARED|VM_NORESERVE))) {
 465                         charged = nrpages;
 466                         if (security_vm_enough_memory_mm(mm, charged))
 467                                 return -ENOMEM;
 468                         newflags |= VM_ACCOUNT;
 469                 }
 470         }
 471
 472         /*
 473          * First try to merge with previous and/or next vma.
 474          */
 475         pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
 476         *pprev = vma_merge(mm, *pprev, start, end, newflags,
 477                            vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
 478                            vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 479         if (*pprev) {
 480                 vma = *pprev;
 481                 VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
 482                 goto success;
 483         }
 484
 485         *pprev = vma;
 486
 487         if (start != vma->vm_start) {
 488                 error = split_vma(mm, vma, start, 1);
 489                 if (error)
 490                         goto fail;
 491         }
 492
 493         if (end != vma->vm_end) {
 494                 error = split_vma(mm, vma, end, 0);
 495                 if (error)
 496                         goto fail;
 497         }
 498
 499 success:
 500         /*
 501          * vm_flags and vm_page_prot are protected by the mmap_lock
 502          * held in write mode.
 503          */
 504         vma->vm_flags = newflags;
 505         dirty_accountable = vma_wants_writenotify(vma, vma->vm_page_prot);
 506         vma_set_page_prot(vma);
 507
 508         change_protection(vma, start, end, vma->vm_page_prot,
 509                           dirty_accountable ? MM_CP_DIRTY_ACCT : 0);
 510
 511         /*
 512          * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
 513          * fault on access.
 514          */
 515         if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
 516                         (newflags & VM_WRITE)) {
 517                 populate_vma_page_range(vma, start, end, NULL);
 518         }
 519
 520         vm_stat_account(mm, oldflags, -nrpages);
 521         vm_stat_account(mm, newflags, nrpages);
 522         perf_event_mmap(vma);
 523         return 0;
 524
 525 fail:
 526         vm_unacct_memory(charged);
 527         return error;
 528 }
 529
 530 /*
 531  * pkey==-1 when doing a legacy mprotect()
 532  */
 533 static int do_mprotect_pkey(unsigned long start, size_t len,
 534                 unsigned long prot, int pkey)
 535 {
 536         unsigned long nstart, end, tmp, reqprot;
 537         struct vm_area_struct *vma, *prev;
 538         int error = -EINVAL;
 539         const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
 540         const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
 541                                 (prot & PROT_READ);
 542
 543         start = untagged_addr(start);
 544
 545         prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
 546         if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
 547                 return -EINVAL;
 548
 549         if (start & ~PAGE_MASK)
 550                 return -EINVAL;
 551         if (!len)
 552                 return 0;
 553         len = PAGE_ALIGN(len);
 554         end = start + len;
 555         if (end <= start)
 556                 return -ENOMEM;
 557         if (!arch_validate_prot(prot, start))
 558                 return -EINVAL;
 559
 560         reqprot = prot;
 561
 562         if (mmap_write_lock_killable(current->mm))
 563                 return -EINTR;
 564
 565         /*
 566          * If userspace did not allocate the pkey, do not let
 567          * them use it here.
 568          */
 569         error = -EINVAL;
 570         if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
 571                 goto out;
 572
 573         vma = find_vma(current->mm, start);
 574         error = -ENOMEM;
 575         if (!vma)
 576                 goto out;
 577
 578         if (unlikely(grows & PROT_GROWSDOWN)) {
 579                 if (vma->vm_start >= end)
 580                         goto out;
 581                 start = vma->vm_start;
 582                 error = -EINVAL;
 583                 if (!(vma->vm_flags & VM_GROWSDOWN))
 584                         goto out;
 585         } else {
 586                 if (vma->vm_start > start)
 587                         goto out;
 588                 if (unlikely(grows & PROT_GROWSUP)) {
 589                         end = vma->vm_end;
 590                         error = -EINVAL;
 591                         if (!(vma->vm_flags & VM_GROWSUP))
 592                                 goto out;
 593                 }
 594         }
 595
 596         if (start > vma->vm_start)
 597                 prev = vma;
 598         else
 599                 prev = vma->vm_prev;
 600
 601         for (nstart = start ; ; ) {
 602                 unsigned long mask_off_old_flags;
 603                 unsigned long newflags;
 604                 int new_vma_pkey;
 605
 606                 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
 607
 608                 /* Does the application expect PROT_READ to imply PROT_EXEC */
 609                 if (rier && (vma->vm_flags & VM_MAYEXEC))
 610                         prot |= PROT_EXEC;
 611
 612                 /*
 613                  * Each mprotect() call explicitly passes r/w/x permissions.
 614                  * If a permission is not passed to mprotect(), it must be
 615                  * cleared from the VMA.
 616                  */
 617                 mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC |
 618                                         VM_FLAGS_CLEAR;
 619
 620                 new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
 621                 newflags = calc_vm_prot_bits(prot, new_vma_pkey);
 622                 newflags |= (vma->vm_flags & ~mask_off_old_flags);
 623
 624                 /* newflags >> 4 shift VM_MAY% in place of VM_% */
 625                 if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
 626                         error = -EACCES;
 627                         goto out;
 628                 }
 629
 630                 /* Allow architectures to sanity-check the new flags */
 631                 if (!arch_validate_flags(newflags)) {
 632                         error = -EINVAL;
 633                         goto out;
 634                 }
 635
 636                 error = security_file_mprotect(vma, reqprot, prot);
 637                 if (error)
 638                         goto out;
 639
 640                 tmp = vma->vm_end;
 641                 if (tmp > end)
 642                         tmp = end;
 643
 644                 if (vma->vm_ops && vma->vm_ops->mprotect) {
 645                         error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
 646                         if (error)
 647                                 goto out;
 648                 }
 649
 650                 error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
 651                 if (error)
 652                         goto out;
 653
 654                 nstart = tmp;
 655
 656                 if (nstart < prev->vm_end)
 657                         nstart = prev->vm_end;
 658                 if (nstart >= end)
 659                         goto out;
 660
 661                 vma = prev->vm_next;
 662                 if (!vma || vma->vm_start != nstart) {
 663                         error = -ENOMEM;
 664                         goto out;
 665                 }
 666                 prot = reqprot;
 667         }
 668 out:
 669         mmap_write_unlock(current->mm);
 670         return error;
 671 }
 672
 673 SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
 674                 unsigned long, prot)
 675 {
 676         return do_mprotect_pkey(start, len, prot, -1);
 677 }
 678
 679 #ifdef CONFIG_ARCH_HAS_PKEYS
 680
 681 SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
 682                 unsigned long, prot, int, pkey)
 683 {
 684         return do_mprotect_pkey(start, len, prot, pkey);
 685 }
 686
 687 SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
 688 {
 689         int pkey;
 690         int ret;
 691
 692         /* No flags supported yet. */
 693         if (flags)
 694                 return -EINVAL;
 695         /* check for unsupported init values */
 696         if (init_val & ~PKEY_ACCESS_MASK)
 697                 return -EINVAL;
 698
 699         mmap_write_lock(current->mm);
 700         pkey = mm_pkey_alloc(current->mm);
 701
 702         ret = -ENOSPC;
 703         if (pkey == -1)
 704                 goto out;
 705
 706         ret = arch_set_user_pkey_access(current, pkey, init_val);
 707         if (ret) {
 708                 mm_pkey_free(current->mm, pkey);
 709                 goto out;
 710         }
 711         ret = pkey;
 712 out:
 713         mmap_write_unlock(current->mm);
 714         return ret;
 715 }
 716
 717 SYSCALL_DEFINE1(pkey_free, int, pkey)
 718 {
 719         int ret;
 720
 721         mmap_write_lock(current->mm);
 722         ret = mm_pkey_free(current->mm, pkey);
 723         mmap_write_unlock(current->mm);
 724
 725         /*
 726          * We could provide warnings or errors if any VMA still
 727          * has the pkey set here.
 728          */
 729         return ret;
 730 }
 731
 732 #endif /* CONFIG_ARCH_HAS_PKEYS */