| From | "Kirill A. Shutemov" <> | Subject | [PATCHv5 03/19] mm/ksm: Do not merge pages with different KeyIDs | Date | Tue, 17 Jul 2018 14:20:13 +0300 |
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Pages encrypted with different encryption keys are not allowed to be merged by KSM. Otherwise it would cross security boundary.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- include/linux/mm.h | 7 +++++++ mm/ksm.c | 3 +++ 2 files changed, 10 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h index 151d6e6b16e5..a4ce26aa0b65 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1551,6 +1551,13 @@ static inline int vma_keyid(struct vm_area_struct *vma) } #endif +#ifndef page_keyid +static inline int page_keyid(struct page *page) +{ + return 0; +} +#endif + #ifdef CONFIG_SHMEM /* * The vma_is_shmem is not inline because it is used only by slow diff --git a/mm/ksm.c b/mm/ksm.c index a6d43cf9a982..1bd7b9710e29 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1214,6 +1214,9 @@ static int try_to_merge_one_page(struct vm_area_struct *vma, if (!PageAnon(page)) goto out; + if (page_keyid(page) != page_keyid(kpage)) + goto out; + /* * We need the page lock to read a stable PageSwapCache in * write_protect_page(). We use trylock_page() instead of -- 2.18.0
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