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mm: /proc/pid/pagemap: hide swap entries from unprivileged users
[ Upstream commitab6ecf247a
] In commitab676b7d6f
("pagemap: do not leak physical addresses to non-privileged userspace"), the /proc/PID/pagemap is restricted to be readable only by CAP_SYS_ADMIN to address some security issue. In commit1c90308e7a
("pagemap: hide physical addresses from non-privileged users"), the restriction is relieved to make /proc/PID/pagemap readable, but hide the physical addresses for non-privileged users. But the swap entries are readable for non-privileged users too. This has some security issues. For example, for page under migrating, the swap entry has physical address information. So, in this patch, the swap entries are hided for non-privileged users too. Link: http://lkml.kernel.org/r/20180508012745.7238-1-ying.huang@intel.com Fixes:1c90308e7a
("pagemap: hide physical addresses from non-privileged users") Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Andrei Vagin <avagin@openvz.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Daniel Colascione <dancol@google.com> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
9691035cbf
commit
9e1a1fc0cd
1 changed files with 16 additions and 10 deletions
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@ -1275,8 +1275,9 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
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if (pte_swp_soft_dirty(pte))
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if (pte_swp_soft_dirty(pte))
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flags |= PM_SOFT_DIRTY;
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flags |= PM_SOFT_DIRTY;
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entry = pte_to_swp_entry(pte);
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entry = pte_to_swp_entry(pte);
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frame = swp_type(entry) |
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if (pm->show_pfn)
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(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
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frame = swp_type(entry) |
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(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
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flags |= PM_SWAP;
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flags |= PM_SWAP;
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if (is_migration_entry(entry))
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if (is_migration_entry(entry))
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page = migration_entry_to_page(entry);
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page = migration_entry_to_page(entry);
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@ -1327,11 +1328,14 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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else if (is_swap_pmd(pmd)) {
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else if (is_swap_pmd(pmd)) {
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swp_entry_t entry = pmd_to_swp_entry(pmd);
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swp_entry_t entry = pmd_to_swp_entry(pmd);
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unsigned long offset = swp_offset(entry);
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unsigned long offset;
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offset += (addr & ~PMD_MASK) >> PAGE_SHIFT;
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if (pm->show_pfn) {
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frame = swp_type(entry) |
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offset = swp_offset(entry) +
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(offset << MAX_SWAPFILES_SHIFT);
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((addr & ~PMD_MASK) >> PAGE_SHIFT);
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frame = swp_type(entry) |
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(offset << MAX_SWAPFILES_SHIFT);
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}
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flags |= PM_SWAP;
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flags |= PM_SWAP;
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if (pmd_swp_soft_dirty(pmd))
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if (pmd_swp_soft_dirty(pmd))
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flags |= PM_SOFT_DIRTY;
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flags |= PM_SOFT_DIRTY;
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@ -1349,10 +1353,12 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
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err = add_to_pagemap(addr, &pme, pm);
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err = add_to_pagemap(addr, &pme, pm);
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if (err)
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if (err)
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break;
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break;
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if (pm->show_pfn && (flags & PM_PRESENT))
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if (pm->show_pfn) {
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frame++;
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if (flags & PM_PRESENT)
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else if (flags & PM_SWAP)
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frame++;
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frame += (1 << MAX_SWAPFILES_SHIFT);
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else if (flags & PM_SWAP)
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frame += (1 << MAX_SWAPFILES_SHIFT);
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}
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}
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}
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spin_unlock(ptl);
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spin_unlock(ptl);
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return err;
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return err;
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