diff options
Diffstat (limited to 'mm/mprotect.c')
| -rw-r--r-- | mm/mprotect.c | 52 |
1 files changed, 51 insertions, 1 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index ef5be8eaab00..fcd678c3bd24 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -72,6 +72,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (!pte) return 0; + flush_tlb_batched_pending(vma->vm_mm); arch_enter_lazy_mmu_mode(); do { oldpte = *pte; @@ -254,6 +255,42 @@ unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, return pages; } +static int prot_none_pte_entry(pte_t *pte, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? + 0 : -EACCES; +} + +static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, + unsigned long addr, unsigned long next, + struct mm_walk *walk) +{ + return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? + 0 : -EACCES; +} + +static int prot_none_test(unsigned long addr, unsigned long next, + struct mm_walk *walk) +{ + return 0; +} + +static int prot_none_walk(struct vm_area_struct *vma, unsigned long start, + unsigned long end, unsigned long newflags) +{ + pgprot_t new_pgprot = vm_get_page_prot(newflags); + struct mm_walk prot_none_walk = { + .pte_entry = prot_none_pte_entry, + .hugetlb_entry = prot_none_hugetlb_entry, + .test_walk = prot_none_test, + .mm = current->mm, + .private = &new_pgprot, + }; + + return walk_page_range(start, end, &prot_none_walk); +} + int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, unsigned long end, unsigned long newflags) @@ -272,6 +309,19 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, } /* + * Do PROT_NONE PFN permission checks here when we can still + * bail out without undoing a lot of state. This is a rather + * uncommon case, so doesn't need to be very optimized. + */ + if (arch_has_pfn_modify_check() && + (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && + (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) { + error = prot_none_walk(vma, start, end, newflags); + if (error) + return error; + } + + /* * If we make a private mapping writable we increase our commit; * but (without finer accounting) cannot reduce our commit if we * make it unwritable again. hugetlb mapping were accounted for @@ -293,7 +343,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); *pprev = vma_merge(mm, *pprev, start, end, newflags, vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx); + vma->vm_userfaultfd_ctx, vma_get_anon_name(vma)); if (*pprev) { vma = *pprev; goto success; |