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df57721f9a
Convert IBT selftest to asm to fix objtool warning -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEV76QKkVc4xCGURexaDWVMHDJkrAFAmTv1QQACgkQaDWVMHDJ krAUwhAAn6TOwHJK8BSkHeiQhON1nrlP3c5cv0AyZ2NP8RYDrZrSZvhpYBJ6wgKC Cx5CGq5nn9twYsYS3KsktLKDfR3lRdsQ7K9qtyFtYiaeaVKo+7gEKl/K+klwai8/ gninQWHk0zmSCja8Vi77q52WOMkQKapT8+vaON9EVDO8dVEi+CvhAIfPwMafuiwO Rk4X86SzoZu9FP79LcCg9XyGC/XbM2OG9eNUTSCKT40qTTKm5y4gix687NvAlaHR ko5MTsdl0Wfp6Qk0ohT74LnoA2c1g/FluvZIM33ci/2rFpkf9Hw7ip3lUXqn6CPx rKiZ+pVRc0xikVWkraMfIGMJfUd2rhelp8OyoozD7DB7UZw40Q4RW4N5tgq9Fhe9 MQs3p1v9N8xHdRKl365UcOczUxNAmv4u0nV5gY/4FMC6VjldCl2V9fmqYXyzFS4/ Ogg4FSd7c2JyGFKPs+5uXyi+RY2qOX4+nzHOoKD7SY616IYqtgKoz5usxETLwZ6s VtJOmJL0h//z0A7tBliB0zd+SQ5UQQBDC2XouQH2fNX2isJMn0UDmWJGjaHgK6Hh 8jVp6LNqf+CEQS387UxckOyj7fu438hDky1Ggaw4YqowEOhQeqLVO4++x+HITrbp AupXfbJw9h9cMN63Yc0gVxXQ9IMZ+M7UxLtZ3Cd8/PVztNy/clA= =3UUm -----END PGP SIGNATURE----- Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 shadow stack support from Dave Hansen: "This is the long awaited x86 shadow stack support, part of Intel's Control-flow Enforcement Technology (CET). CET consists of two related security features: shadow stacks and indirect branch tracking. This series implements just the shadow stack part of this feature, and just for userspace. The main use case for shadow stack is providing protection against return oriented programming attacks. It works by maintaining a secondary (shadow) stack using a special memory type that has protections against modification. When executing a CALL instruction, the processor pushes the return address to both the normal stack and to the special permission shadow stack. Upon RET, the processor pops the shadow stack copy and compares it to the normal stack copy. For more information, refer to the links below for the earlier versions of this patch set" Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/ Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/ * tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits) x86/shstk: Change order of __user in type x86/ibt: Convert IBT selftest to asm x86/shstk: Don't retry vm_munmap() on -EINTR x86/kbuild: Fix Documentation/ reference x86/shstk: Move arch detail comment out of core mm x86/shstk: Add ARCH_SHSTK_STATUS x86/shstk: Add ARCH_SHSTK_UNLOCK x86: Add PTRACE interface for shadow stack selftests/x86: Add shadow stack test x86/cpufeatures: Enable CET CR4 bit for shadow stack x86/shstk: Wire in shadow stack interface x86: Expose thread features in /proc/$PID/status x86/shstk: Support WRSS for userspace x86/shstk: Introduce map_shadow_stack syscall x86/shstk: Check that signal frame is shadow stack mem x86/shstk: Check that SSP is aligned on sigreturn x86/shstk: Handle signals for shadow stack x86/shstk: Introduce routines modifying shstk x86/shstk: Handle thread shadow stack x86/shstk: Add user-mode shadow stack support ...
897 lines
23 KiB
C
897 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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/pagewalk.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 <linux/pkeys.h>
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#include <linux/ksm.h>
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#include <linux/uaccess.h>
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#include <linux/mm_inline.h>
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#include <linux/pgtable.h>
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#include <linux/sched/sysctl.h>
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#include <linux/userfaultfd_k.h>
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#include <linux/memory-tiers.h>
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#include <asm/cacheflush.h>
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#include <asm/mmu_context.h>
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#include <asm/tlbflush.h>
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#include <asm/tlb.h>
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#include "internal.h"
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bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
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pte_t pte)
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{
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struct page *page;
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if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))
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return false;
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/* Don't touch entries that are not even readable. */
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if (pte_protnone(pte))
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return false;
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/* Do we need write faults for softdirty tracking? */
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if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte))
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return false;
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/* Do we need write faults for uffd-wp tracking? */
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if (userfaultfd_pte_wp(vma, pte))
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return false;
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if (!(vma->vm_flags & VM_SHARED)) {
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/*
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* Writable MAP_PRIVATE mapping: We can only special-case on
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* exclusive anonymous pages, because we know that our
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* write-fault handler similarly would map them writable without
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* any additional checks while holding the PT lock.
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*/
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page = vm_normal_page(vma, addr, pte);
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return page && PageAnon(page) && PageAnonExclusive(page);
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}
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/*
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* Writable MAP_SHARED mapping: "clean" might indicate that the FS still
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* needs a real write-fault for writenotify
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* (see vma_wants_writenotify()). If "dirty", the assumption is that the
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* FS was already notified and we can simply mark the PTE writable
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* just like the write-fault handler would do.
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*/
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return pte_dirty(pte);
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}
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static long change_pte_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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pte_t *pte, oldpte;
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spinlock_t *ptl;
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long pages = 0;
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int target_node = NUMA_NO_NODE;
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bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
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bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
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bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
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tlb_change_page_size(tlb, PAGE_SIZE);
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pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
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if (!pte)
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return -EAGAIN;
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/* Get target node for single threaded private VMAs */
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if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
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atomic_read(&vma->vm_mm->mm_users) == 1)
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target_node = numa_node_id();
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flush_tlb_batched_pending(vma->vm_mm);
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arch_enter_lazy_mmu_mode();
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do {
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oldpte = ptep_get(pte);
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if (pte_present(oldpte)) {
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pte_t ptent;
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/*
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* Avoid trapping faults against the zero or KSM
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* pages. See similar comment in change_huge_pmd.
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*/
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if (prot_numa) {
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struct page *page;
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int nid;
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bool toptier;
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/* Avoid TLB flush if possible */
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if (pte_protnone(oldpte))
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continue;
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page = vm_normal_page(vma, addr, oldpte);
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if (!page || is_zone_device_page(page) || PageKsm(page))
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continue;
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/* Also skip shared copy-on-write pages */
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if (is_cow_mapping(vma->vm_flags) &&
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page_count(page) != 1)
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continue;
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/*
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* While migration can move some dirty pages,
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* it cannot move them all from MIGRATE_ASYNC
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* context.
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*/
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if (page_is_file_lru(page) && PageDirty(page))
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continue;
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/*
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* Don't mess with PTEs if page is already on the node
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* a single-threaded process is running on.
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*/
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nid = page_to_nid(page);
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if (target_node == nid)
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continue;
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toptier = node_is_toptier(nid);
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/*
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* Skip scanning top tier node if normal numa
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* balancing is disabled
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*/
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if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
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toptier)
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continue;
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if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
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!toptier)
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xchg_page_access_time(page,
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jiffies_to_msecs(jiffies));
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}
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oldpte = ptep_modify_prot_start(vma, addr, pte);
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ptent = pte_modify(oldpte, newprot);
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if (uffd_wp)
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ptent = pte_mkuffd_wp(ptent);
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else if (uffd_wp_resolve)
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ptent = pte_clear_uffd_wp(ptent);
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/*
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* In some writable, shared mappings, we might want
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* to catch actual write access -- see
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* vma_wants_writenotify().
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*
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* In all writable, private mappings, we have to
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* properly handle COW.
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*
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* In both cases, we can sometimes still change PTEs
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* writable and avoid the write-fault handler, for
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* example, if a PTE is already dirty and no other
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* COW or special handling is required.
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*/
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if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
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!pte_write(ptent) &&
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can_change_pte_writable(vma, addr, ptent))
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ptent = pte_mkwrite(ptent, vma);
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ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
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if (pte_needs_flush(oldpte, ptent))
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tlb_flush_pte_range(tlb, addr, PAGE_SIZE);
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pages++;
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} else if (is_swap_pte(oldpte)) {
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swp_entry_t entry = pte_to_swp_entry(oldpte);
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pte_t newpte;
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if (is_writable_migration_entry(entry)) {
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struct page *page = pfn_swap_entry_to_page(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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if (PageAnon(page))
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entry = make_readable_exclusive_migration_entry(
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swp_offset(entry));
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else
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entry = make_readable_migration_entry(swp_offset(entry));
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newpte = swp_entry_to_pte(entry);
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if (pte_swp_soft_dirty(oldpte))
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newpte = pte_swp_mksoft_dirty(newpte);
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} else if (is_writable_device_private_entry(entry)) {
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/*
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* We do not preserve soft-dirtiness. See
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* copy_nonpresent_pte() for explanation.
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*/
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entry = make_readable_device_private_entry(
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swp_offset(entry));
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newpte = swp_entry_to_pte(entry);
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if (pte_swp_uffd_wp(oldpte))
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newpte = pte_swp_mkuffd_wp(newpte);
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} else if (is_writable_device_exclusive_entry(entry)) {
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entry = make_readable_device_exclusive_entry(
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swp_offset(entry));
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newpte = swp_entry_to_pte(entry);
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if (pte_swp_soft_dirty(oldpte))
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newpte = pte_swp_mksoft_dirty(newpte);
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if (pte_swp_uffd_wp(oldpte))
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newpte = pte_swp_mkuffd_wp(newpte);
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} else if (is_pte_marker_entry(entry)) {
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/*
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* Ignore error swap entries unconditionally,
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* because any access should sigbus anyway.
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*/
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if (is_poisoned_swp_entry(entry))
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continue;
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/*
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* If this is uffd-wp pte marker and we'd like
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* to unprotect it, drop it; the next page
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* fault will trigger without uffd trapping.
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*/
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if (uffd_wp_resolve) {
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pte_clear(vma->vm_mm, addr, pte);
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pages++;
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}
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continue;
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} else {
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newpte = oldpte;
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}
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if (uffd_wp)
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newpte = pte_swp_mkuffd_wp(newpte);
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else if (uffd_wp_resolve)
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newpte = pte_swp_clear_uffd_wp(newpte);
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if (!pte_same(oldpte, newpte)) {
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set_pte_at(vma->vm_mm, addr, pte, newpte);
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pages++;
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}
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} else {
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/* It must be an none page, or what else?.. */
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WARN_ON_ONCE(!pte_none(oldpte));
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/*
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* Nobody plays with any none ptes besides
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* userfaultfd when applying the protections.
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*/
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if (likely(!uffd_wp))
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continue;
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if (userfaultfd_wp_use_markers(vma)) {
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/*
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* For file-backed mem, we need to be able to
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* wr-protect a none pte, because even if the
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* pte is none, the page/swap cache could
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* exist. Doing that by install a marker.
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*/
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set_pte_at(vma->vm_mm, addr, pte,
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make_pte_marker(PTE_MARKER_UFFD_WP));
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pages++;
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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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return pages;
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}
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/*
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* Return true if we want to split THPs into PTE mappings in change
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* protection procedure, false otherwise.
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*/
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static inline bool
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pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
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{
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/*
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* pte markers only resides in pte level, if we need pte markers,
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* we need to split. We cannot wr-protect shmem thp because file
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* thp is handled differently when split by erasing the pmd so far.
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*/
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return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
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}
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/*
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* Return true if we want to populate pgtables in change protection
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* procedure, false otherwise
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*/
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static inline bool
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pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
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{
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/* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */
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if (!(cp_flags & MM_CP_UFFD_WP))
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return false;
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/* Populate if the userfaultfd mode requires pte markers */
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return userfaultfd_wp_use_markers(vma);
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}
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/*
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* Populate the pgtable underneath for whatever reason if requested.
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* When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
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* allocation failures during page faults by kicking OOM and returning
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* error.
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*/
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#define change_pmd_prepare(vma, pmd, cp_flags) \
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({ \
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long err = 0; \
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if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
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if (pte_alloc(vma->vm_mm, pmd)) \
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err = -ENOMEM; \
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} \
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err; \
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})
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/*
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* This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
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* have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
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* while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
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*/
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#define change_prepare(vma, high, low, addr, cp_flags) \
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({ \
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long err = 0; \
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if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
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low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
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if (p == NULL) \
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err = -ENOMEM; \
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} \
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err; \
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})
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static inline long change_pmd_range(struct mmu_gather *tlb,
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struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
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unsigned long end, pgprot_t newprot, unsigned long cp_flags)
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{
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pmd_t *pmd;
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unsigned long next;
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long pages = 0;
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unsigned long nr_huge_updates = 0;
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struct mmu_notifier_range range;
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range.start = 0;
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pmd = pmd_offset(pud, addr);
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do {
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long ret;
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pmd_t _pmd;
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again:
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next = pmd_addr_end(addr, end);
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ret = change_pmd_prepare(vma, pmd, cp_flags);
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if (ret) {
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pages = ret;
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break;
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}
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if (pmd_none(*pmd))
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goto next;
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/* invoke the mmu notifier if the pmd is populated */
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if (!range.start) {
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mmu_notifier_range_init(&range,
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MMU_NOTIFY_PROTECTION_VMA, 0,
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vma->vm_mm, addr, end);
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mmu_notifier_invalidate_range_start(&range);
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}
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_pmd = pmdp_get_lockless(pmd);
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if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd) || pmd_devmap(_pmd)) {
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if ((next - addr != HPAGE_PMD_SIZE) ||
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pgtable_split_needed(vma, cp_flags)) {
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__split_huge_pmd(vma, pmd, addr, false, NULL);
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/*
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* For file-backed, the pmd could have been
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* cleared; make sure pmd populated if
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* necessary, then fall-through to pte level.
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*/
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ret = change_pmd_prepare(vma, pmd, cp_flags);
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if (ret) {
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pages = ret;
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break;
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}
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} else {
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ret = change_huge_pmd(tlb, vma, pmd,
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addr, newprot, cp_flags);
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if (ret) {
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if (ret == HPAGE_PMD_NR) {
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pages += HPAGE_PMD_NR;
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nr_huge_updates++;
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}
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/* huge pmd was handled */
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goto next;
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}
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}
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/* fall through, the trans huge pmd just split */
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}
|
|
|
|
ret = change_pte_range(tlb, vma, pmd, addr, next, newprot,
|
|
cp_flags);
|
|
if (ret < 0)
|
|
goto again;
|
|
pages += ret;
|
|
next:
|
|
cond_resched();
|
|
} while (pmd++, addr = next, addr != end);
|
|
|
|
if (range.start)
|
|
mmu_notifier_invalidate_range_end(&range);
|
|
|
|
if (nr_huge_updates)
|
|
count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
|
|
return pages;
|
|
}
|
|
|
|
static inline long change_pud_range(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
|
|
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
|
|
{
|
|
pud_t *pud;
|
|
unsigned long next;
|
|
long pages = 0, ret;
|
|
|
|
pud = pud_offset(p4d, addr);
|
|
do {
|
|
next = pud_addr_end(addr, end);
|
|
ret = change_prepare(vma, pud, pmd, addr, cp_flags);
|
|
if (ret)
|
|
return ret;
|
|
if (pud_none_or_clear_bad(pud))
|
|
continue;
|
|
pages += change_pmd_range(tlb, vma, pud, addr, next, newprot,
|
|
cp_flags);
|
|
} while (pud++, addr = next, addr != end);
|
|
|
|
return pages;
|
|
}
|
|
|
|
static inline long change_p4d_range(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
|
|
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
|
|
{
|
|
p4d_t *p4d;
|
|
unsigned long next;
|
|
long pages = 0, ret;
|
|
|
|
p4d = p4d_offset(pgd, addr);
|
|
do {
|
|
next = p4d_addr_end(addr, end);
|
|
ret = change_prepare(vma, p4d, pud, addr, cp_flags);
|
|
if (ret)
|
|
return ret;
|
|
if (p4d_none_or_clear_bad(p4d))
|
|
continue;
|
|
pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
|
|
cp_flags);
|
|
} while (p4d++, addr = next, addr != end);
|
|
|
|
return pages;
|
|
}
|
|
|
|
static long change_protection_range(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, unsigned long addr,
|
|
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
pgd_t *pgd;
|
|
unsigned long next;
|
|
long pages = 0, ret;
|
|
|
|
BUG_ON(addr >= end);
|
|
pgd = pgd_offset(mm, addr);
|
|
tlb_start_vma(tlb, vma);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
ret = change_prepare(vma, pgd, p4d, addr, cp_flags);
|
|
if (ret) {
|
|
pages = ret;
|
|
break;
|
|
}
|
|
if (pgd_none_or_clear_bad(pgd))
|
|
continue;
|
|
pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot,
|
|
cp_flags);
|
|
} while (pgd++, addr = next, addr != end);
|
|
|
|
tlb_end_vma(tlb, vma);
|
|
|
|
return pages;
|
|
}
|
|
|
|
long change_protection(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, unsigned long start,
|
|
unsigned long end, unsigned long cp_flags)
|
|
{
|
|
pgprot_t newprot = vma->vm_page_prot;
|
|
long pages;
|
|
|
|
BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
|
|
|
|
#ifdef CONFIG_NUMA_BALANCING
|
|
/*
|
|
* Ordinary protection updates (mprotect, uffd-wp, softdirty tracking)
|
|
* are expected to reflect their requirements via VMA flags such that
|
|
* vma_set_page_prot() will adjust vma->vm_page_prot accordingly.
|
|
*/
|
|
if (cp_flags & MM_CP_PROT_NUMA)
|
|
newprot = PAGE_NONE;
|
|
#else
|
|
WARN_ON_ONCE(cp_flags & MM_CP_PROT_NUMA);
|
|
#endif
|
|
|
|
if (is_vm_hugetlb_page(vma))
|
|
pages = hugetlb_change_protection(vma, start, end, newprot,
|
|
cp_flags);
|
|
else
|
|
pages = change_protection_range(tlb, vma, start, end, newprot,
|
|
cp_flags);
|
|
|
|
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(ptep_get(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(ptep_get(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 const struct mm_walk_ops prot_none_walk_ops = {
|
|
.pte_entry = prot_none_pte_entry,
|
|
.hugetlb_entry = prot_none_hugetlb_entry,
|
|
.test_walk = prot_none_test,
|
|
.walk_lock = PGWALK_WRLOCK,
|
|
};
|
|
|
|
int
|
|
mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, struct vm_area_struct **pprev,
|
|
unsigned long start, unsigned long end, unsigned long newflags)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
unsigned long oldflags = vma->vm_flags;
|
|
long nrpages = (end - start) >> PAGE_SHIFT;
|
|
unsigned int mm_cp_flags = 0;
|
|
unsigned long charged = 0;
|
|
pgoff_t pgoff;
|
|
int error;
|
|
|
|
if (newflags == oldflags) {
|
|
*pprev = vma;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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_ACCESS_FLAGS) == 0) {
|
|
pgprot_t new_pgprot = vm_get_page_prot(newflags);
|
|
|
|
error = walk_page_range(current->mm, start, end,
|
|
&prot_none_walk_ops, &new_pgprot);
|
|
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
|
|
* even if read-only so there is no need to account for them here
|
|
*/
|
|
if (newflags & VM_WRITE) {
|
|
/* Check space limits when area turns into data. */
|
|
if (!may_expand_vm(mm, newflags, nrpages) &&
|
|
may_expand_vm(mm, oldflags, nrpages))
|
|
return -ENOMEM;
|
|
if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
|
|
VM_SHARED|VM_NORESERVE))) {
|
|
charged = nrpages;
|
|
if (security_vm_enough_memory_mm(mm, charged))
|
|
return -ENOMEM;
|
|
newflags |= VM_ACCOUNT;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* First try to merge with previous and/or next vma.
|
|
*/
|
|
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
|
|
*pprev = vma_merge(vmi, mm, *pprev, start, end, newflags,
|
|
vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
|
|
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
|
|
if (*pprev) {
|
|
vma = *pprev;
|
|
VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
|
|
goto success;
|
|
}
|
|
|
|
*pprev = vma;
|
|
|
|
if (start != vma->vm_start) {
|
|
error = split_vma(vmi, vma, start, 1);
|
|
if (error)
|
|
goto fail;
|
|
}
|
|
|
|
if (end != vma->vm_end) {
|
|
error = split_vma(vmi, vma, end, 0);
|
|
if (error)
|
|
goto fail;
|
|
}
|
|
|
|
success:
|
|
/*
|
|
* vm_flags and vm_page_prot are protected by the mmap_lock
|
|
* held in write mode.
|
|
*/
|
|
vma_start_write(vma);
|
|
vm_flags_reset(vma, newflags);
|
|
if (vma_wants_manual_pte_write_upgrade(vma))
|
|
mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
|
|
vma_set_page_prot(vma);
|
|
|
|
change_protection(tlb, vma, start, end, mm_cp_flags);
|
|
|
|
/*
|
|
* Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
|
|
* fault on access.
|
|
*/
|
|
if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
|
|
(newflags & VM_WRITE)) {
|
|
populate_vma_page_range(vma, start, end, NULL);
|
|
}
|
|
|
|
vm_stat_account(mm, oldflags, -nrpages);
|
|
vm_stat_account(mm, newflags, nrpages);
|
|
perf_event_mmap(vma);
|
|
return 0;
|
|
|
|
fail:
|
|
vm_unacct_memory(charged);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* pkey==-1 when doing a legacy mprotect()
|
|
*/
|
|
static int do_mprotect_pkey(unsigned long start, size_t len,
|
|
unsigned long prot, int pkey)
|
|
{
|
|
unsigned long nstart, end, tmp, reqprot;
|
|
struct vm_area_struct *vma, *prev;
|
|
int error;
|
|
const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
|
|
const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
|
|
(prot & PROT_READ);
|
|
struct mmu_gather tlb;
|
|
struct vma_iterator vmi;
|
|
|
|
start = untagged_addr(start);
|
|
|
|
prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
|
|
if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
|
|
return -EINVAL;
|
|
|
|
if (start & ~PAGE_MASK)
|
|
return -EINVAL;
|
|
if (!len)
|
|
return 0;
|
|
len = PAGE_ALIGN(len);
|
|
end = start + len;
|
|
if (end <= start)
|
|
return -ENOMEM;
|
|
if (!arch_validate_prot(prot, start))
|
|
return -EINVAL;
|
|
|
|
reqprot = prot;
|
|
|
|
if (mmap_write_lock_killable(current->mm))
|
|
return -EINTR;
|
|
|
|
/*
|
|
* If userspace did not allocate the pkey, do not let
|
|
* them use it here.
|
|
*/
|
|
error = -EINVAL;
|
|
if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
|
|
goto out;
|
|
|
|
vma_iter_init(&vmi, current->mm, start);
|
|
vma = vma_find(&vmi, end);
|
|
error = -ENOMEM;
|
|
if (!vma)
|
|
goto out;
|
|
|
|
if (unlikely(grows & PROT_GROWSDOWN)) {
|
|
if (vma->vm_start >= end)
|
|
goto out;
|
|
start = vma->vm_start;
|
|
error = -EINVAL;
|
|
if (!(vma->vm_flags & VM_GROWSDOWN))
|
|
goto out;
|
|
} else {
|
|
if (vma->vm_start > start)
|
|
goto out;
|
|
if (unlikely(grows & PROT_GROWSUP)) {
|
|
end = vma->vm_end;
|
|
error = -EINVAL;
|
|
if (!(vma->vm_flags & VM_GROWSUP))
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
prev = vma_prev(&vmi);
|
|
if (start > vma->vm_start)
|
|
prev = vma;
|
|
|
|
tlb_gather_mmu(&tlb, current->mm);
|
|
nstart = start;
|
|
tmp = vma->vm_start;
|
|
for_each_vma_range(vmi, vma, end) {
|
|
unsigned long mask_off_old_flags;
|
|
unsigned long newflags;
|
|
int new_vma_pkey;
|
|
|
|
if (vma->vm_start != tmp) {
|
|
error = -ENOMEM;
|
|
break;
|
|
}
|
|
|
|
/* Does the application expect PROT_READ to imply PROT_EXEC */
|
|
if (rier && (vma->vm_flags & VM_MAYEXEC))
|
|
prot |= PROT_EXEC;
|
|
|
|
/*
|
|
* Each mprotect() call explicitly passes r/w/x permissions.
|
|
* If a permission is not passed to mprotect(), it must be
|
|
* cleared from the VMA.
|
|
*/
|
|
mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR;
|
|
|
|
new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
|
|
newflags = calc_vm_prot_bits(prot, new_vma_pkey);
|
|
newflags |= (vma->vm_flags & ~mask_off_old_flags);
|
|
|
|
/* newflags >> 4 shift VM_MAY% in place of VM_% */
|
|
if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
|
|
error = -EACCES;
|
|
break;
|
|
}
|
|
|
|
if (map_deny_write_exec(vma, newflags)) {
|
|
error = -EACCES;
|
|
break;
|
|
}
|
|
|
|
/* Allow architectures to sanity-check the new flags */
|
|
if (!arch_validate_flags(newflags)) {
|
|
error = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
error = security_file_mprotect(vma, reqprot, prot);
|
|
if (error)
|
|
break;
|
|
|
|
tmp = vma->vm_end;
|
|
if (tmp > end)
|
|
tmp = end;
|
|
|
|
if (vma->vm_ops && vma->vm_ops->mprotect) {
|
|
error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
|
|
if (error)
|
|
break;
|
|
}
|
|
|
|
error = mprotect_fixup(&vmi, &tlb, vma, &prev, nstart, tmp, newflags);
|
|
if (error)
|
|
break;
|
|
|
|
tmp = vma_iter_end(&vmi);
|
|
nstart = tmp;
|
|
prot = reqprot;
|
|
}
|
|
tlb_finish_mmu(&tlb);
|
|
|
|
if (!error && tmp < end)
|
|
error = -ENOMEM;
|
|
|
|
out:
|
|
mmap_write_unlock(current->mm);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
|
|
unsigned long, prot)
|
|
{
|
|
return do_mprotect_pkey(start, len, prot, -1);
|
|
}
|
|
|
|
#ifdef CONFIG_ARCH_HAS_PKEYS
|
|
|
|
SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
|
|
unsigned long, prot, int, pkey)
|
|
{
|
|
return do_mprotect_pkey(start, len, prot, pkey);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
|
|
{
|
|
int pkey;
|
|
int ret;
|
|
|
|
/* No flags supported yet. */
|
|
if (flags)
|
|
return -EINVAL;
|
|
/* check for unsupported init values */
|
|
if (init_val & ~PKEY_ACCESS_MASK)
|
|
return -EINVAL;
|
|
|
|
mmap_write_lock(current->mm);
|
|
pkey = mm_pkey_alloc(current->mm);
|
|
|
|
ret = -ENOSPC;
|
|
if (pkey == -1)
|
|
goto out;
|
|
|
|
ret = arch_set_user_pkey_access(current, pkey, init_val);
|
|
if (ret) {
|
|
mm_pkey_free(current->mm, pkey);
|
|
goto out;
|
|
}
|
|
ret = pkey;
|
|
out:
|
|
mmap_write_unlock(current->mm);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(pkey_free, int, pkey)
|
|
{
|
|
int ret;
|
|
|
|
mmap_write_lock(current->mm);
|
|
ret = mm_pkey_free(current->mm, pkey);
|
|
mmap_write_unlock(current->mm);
|
|
|
|
/*
|
|
* We could provide warnings or errors if any VMA still
|
|
* has the pkey set here.
|
|
*/
|
|
return ret;
|
|
}
|
|
|
|
#endif /* CONFIG_ARCH_HAS_PKEYS */
|