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![Linus Torvalds](/assets/img/avatar_default.png)
Pull security subsystem updates for 3.4 from James Morris: "The main addition here is the new Yama security module from Kees Cook, which was discussed at the Linux Security Summit last year. Its purpose is to collect miscellaneous DAC security enhancements in one place. This also marks a departure in policy for LSM modules, which were previously limited to being standalone access control systems. Chromium OS is using Yama, and I believe there are plans for Ubuntu, at least. This patchset also includes maintenance updates for AppArmor, TOMOYO and others." Fix trivial conflict in <net/sock.h> due to the jumo_label->static_key rename. * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (38 commits) AppArmor: Fix location of const qualifier on generated string tables TOMOYO: Return error if fails to delete a domain AppArmor: add const qualifiers to string arrays AppArmor: Add ability to load extended policy TOMOYO: Return appropriate value to poll(). AppArmor: Move path failure information into aa_get_name and rename AppArmor: Update dfa matching routines. AppArmor: Minor cleanup of d_namespace_path to consolidate error handling AppArmor: Retrieve the dentry_path for error reporting when path lookup fails AppArmor: Add const qualifiers to generated string tables AppArmor: Fix oops in policy unpack auditing AppArmor: Fix error returned when a path lookup is disconnected KEYS: testing wrong bit for KEY_FLAG_REVOKED TOMOYO: Fix mount flags checking order. security: fix ima kconfig warning AppArmor: Fix the error case for chroot relative path name lookup AppArmor: fix mapping of META_READ to audit and quiet flags AppArmor: Fix underflow in xindex calculation AppArmor: Fix dropping of allowed operations that are force audited AppArmor: Add mising end of structure test to caps unpacking ...
330 lines
7.9 KiB
C
330 lines
7.9 KiB
C
/*
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* mm/mprotect.c
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*
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* (C) Copyright 1994 Linus Torvalds
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* (C) Copyright 2002 Christoph Hellwig
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*
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* Address space accounting code <alan@lxorguk.ukuu.org.uk>
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* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/shm.h>
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#include <linux/mman.h>
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#include <linux/fs.h>
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#include <linux/highmem.h>
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#include <linux/security.h>
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#include <linux/mempolicy.h>
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#include <linux/personality.h>
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#include <linux/syscalls.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/mmu_notifier.h>
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#include <linux/migrate.h>
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#include <linux/perf_event.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#ifndef pgprot_modify
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static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
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{
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return newprot;
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}
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#endif
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static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
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unsigned long addr, unsigned long end, pgprot_t newprot,
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int dirty_accountable)
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{
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pte_t *pte, oldpte;
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spinlock_t *ptl;
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pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
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arch_enter_lazy_mmu_mode();
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do {
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oldpte = *pte;
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if (pte_present(oldpte)) {
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pte_t ptent;
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ptent = ptep_modify_prot_start(mm, addr, pte);
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ptent = pte_modify(ptent, newprot);
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/*
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* Avoid taking write faults for pages we know to be
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* dirty.
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*/
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if (dirty_accountable && pte_dirty(ptent))
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ptent = pte_mkwrite(ptent);
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ptep_modify_prot_commit(mm, addr, pte, ptent);
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} else if (PAGE_MIGRATION && !pte_file(oldpte)) {
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swp_entry_t entry = pte_to_swp_entry(oldpte);
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if (is_write_migration_entry(entry)) {
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/*
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* A protection check is difficult so
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* just be safe and disable write
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*/
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make_migration_entry_read(&entry);
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set_pte_at(mm, addr, pte,
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swp_entry_to_pte(entry));
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}
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}
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} while (pte++, addr += PAGE_SIZE, addr != end);
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arch_leave_lazy_mmu_mode();
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pte_unmap_unlock(pte - 1, ptl);
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}
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static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud,
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unsigned long addr, unsigned long end, pgprot_t newprot,
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int dirty_accountable)
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{
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pmd_t *pmd;
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unsigned long next;
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pmd = pmd_offset(pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_trans_huge(*pmd)) {
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if (next - addr != HPAGE_PMD_SIZE)
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split_huge_page_pmd(vma->vm_mm, pmd);
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else if (change_huge_pmd(vma, pmd, addr, newprot))
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continue;
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/* fall through */
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}
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if (pmd_none_or_clear_bad(pmd))
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continue;
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change_pte_range(vma->vm_mm, pmd, addr, next, newprot,
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dirty_accountable);
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} while (pmd++, addr = next, addr != end);
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}
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static inline void change_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
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unsigned long addr, unsigned long end, pgprot_t newprot,
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int dirty_accountable)
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{
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pud_t *pud;
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unsigned long next;
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pud = pud_offset(pgd, addr);
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do {
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next = pud_addr_end(addr, end);
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if (pud_none_or_clear_bad(pud))
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continue;
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change_pmd_range(vma, pud, addr, next, newprot,
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dirty_accountable);
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} while (pud++, addr = next, addr != end);
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}
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static void change_protection(struct vm_area_struct *vma,
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unsigned long addr, unsigned long end, pgprot_t newprot,
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int dirty_accountable)
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{
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struct mm_struct *mm = vma->vm_mm;
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pgd_t *pgd;
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unsigned long next;
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unsigned long start = addr;
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BUG_ON(addr >= end);
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pgd = pgd_offset(mm, addr);
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flush_cache_range(vma, addr, end);
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do {
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next = pgd_addr_end(addr, end);
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if (pgd_none_or_clear_bad(pgd))
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continue;
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change_pud_range(vma, pgd, addr, next, newprot,
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dirty_accountable);
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} while (pgd++, addr = next, addr != end);
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flush_tlb_range(vma, start, end);
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}
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int
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mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
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unsigned long start, unsigned long end, unsigned long newflags)
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{
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struct mm_struct *mm = vma->vm_mm;
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unsigned long oldflags = vma->vm_flags;
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long nrpages = (end - start) >> PAGE_SHIFT;
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unsigned long charged = 0;
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pgoff_t pgoff;
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int error;
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int dirty_accountable = 0;
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if (newflags == oldflags) {
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*pprev = vma;
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return 0;
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}
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/*
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* If we make a private mapping writable we increase our commit;
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* but (without finer accounting) cannot reduce our commit if we
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* make it unwritable again. hugetlb mapping were accounted for
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* even if read-only so there is no need to account for them here
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*/
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if (newflags & VM_WRITE) {
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if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
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VM_SHARED|VM_NORESERVE))) {
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charged = nrpages;
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if (security_vm_enough_memory_mm(mm, charged))
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return -ENOMEM;
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newflags |= VM_ACCOUNT;
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}
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}
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/*
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* First try to merge with previous and/or next vma.
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*/
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pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
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*pprev = vma_merge(mm, *pprev, start, end, newflags,
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vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
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if (*pprev) {
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vma = *pprev;
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goto success;
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}
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*pprev = vma;
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if (start != vma->vm_start) {
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error = split_vma(mm, vma, start, 1);
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if (error)
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goto fail;
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}
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if (end != vma->vm_end) {
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error = split_vma(mm, vma, end, 0);
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if (error)
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goto fail;
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}
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success:
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/*
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* vm_flags and vm_page_prot are protected by the mmap_sem
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* held in write mode.
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*/
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vma->vm_flags = newflags;
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vma->vm_page_prot = pgprot_modify(vma->vm_page_prot,
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vm_get_page_prot(newflags));
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if (vma_wants_writenotify(vma)) {
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vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
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dirty_accountable = 1;
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}
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mmu_notifier_invalidate_range_start(mm, start, end);
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if (is_vm_hugetlb_page(vma))
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hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
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else
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change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable);
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mmu_notifier_invalidate_range_end(mm, start, end);
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vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
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vm_stat_account(mm, newflags, vma->vm_file, nrpages);
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perf_event_mmap(vma);
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return 0;
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fail:
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vm_unacct_memory(charged);
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return error;
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}
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SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
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unsigned long, prot)
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{
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unsigned long vm_flags, nstart, end, tmp, reqprot;
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struct vm_area_struct *vma, *prev;
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int error = -EINVAL;
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const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
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prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
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if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
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return -EINVAL;
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if (start & ~PAGE_MASK)
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return -EINVAL;
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if (!len)
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return 0;
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len = PAGE_ALIGN(len);
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end = start + len;
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if (end <= start)
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return -ENOMEM;
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if (!arch_validate_prot(prot))
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return -EINVAL;
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reqprot = prot;
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/*
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* Does the application expect PROT_READ to imply PROT_EXEC:
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*/
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if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
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prot |= PROT_EXEC;
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vm_flags = calc_vm_prot_bits(prot);
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down_write(¤t->mm->mmap_sem);
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vma = find_vma(current->mm, start);
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error = -ENOMEM;
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if (!vma)
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goto out;
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prev = vma->vm_prev;
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if (unlikely(grows & PROT_GROWSDOWN)) {
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if (vma->vm_start >= end)
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goto out;
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start = vma->vm_start;
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error = -EINVAL;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto out;
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}
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else {
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if (vma->vm_start > start)
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goto out;
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if (unlikely(grows & PROT_GROWSUP)) {
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end = vma->vm_end;
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error = -EINVAL;
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if (!(vma->vm_flags & VM_GROWSUP))
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goto out;
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}
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}
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if (start > vma->vm_start)
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prev = vma;
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for (nstart = start ; ; ) {
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unsigned long newflags;
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/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
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newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
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/* newflags >> 4 shift VM_MAY% in place of VM_% */
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if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
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error = -EACCES;
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goto out;
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}
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error = security_file_mprotect(vma, reqprot, prot);
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if (error)
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goto out;
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tmp = vma->vm_end;
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if (tmp > end)
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tmp = end;
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error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
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if (error)
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goto out;
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nstart = tmp;
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if (nstart < prev->vm_end)
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nstart = prev->vm_end;
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if (nstart >= end)
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goto out;
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vma = prev->vm_next;
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if (!vma || vma->vm_start != nstart) {
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error = -ENOMEM;
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goto out;
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}
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}
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out:
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up_write(¤t->mm->mmap_sem);
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return error;
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}
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