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| author | Laura Abbott <labbott@fedoraproject.org> | 2016-03-16 00:56:27 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-16 02:55:16 +0300 |
| commit | 8823b1dbc05fab1a8bec275eeae4709257c2661d (patch) | |
| tree | a7d6683189c1656ac0879a0a7e9f39c695abfeee /mm/page_alloc.c | |
| parent | ff8e81163889ac4c7f59e7f7db6377d0c5d8d69c (diff) | |
| download | linux-8823b1dbc05fab1a8bec275eeae4709257c2661d.tar.xz | |
mm/page_poison.c: enable PAGE_POISONING as a separate option
Page poisoning is currently set up as a feature if architectures don't
have architecture debug page_alloc to allow unmapping of pages. It has
uses apart from that though. Clearing of the pages on free provides an
increase in security as it helps to limit the risk of information leaks.
Allow page poisoning to be enabled as a separate option independent of
kernel_map pages since the two features do separate work. Because of
how hiberanation is implemented, the checks on alloc cannot occur if
hibernation is enabled. The runtime alloc checks can also be enabled
with an option when !HIBERNATION.
Credit to Grsecurity/PaX team for inspiring this work
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0691403aed93..2a08349fbab2 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1025,6 +1025,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order) PAGE_SIZE << order); } arch_free_page(page, order); + kernel_poison_pages(page, 1 << order, 0); kernel_map_pages(page, 1 << order, 0); return true; @@ -1420,6 +1421,7 @@ static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, arch_alloc_page(page, order); kernel_map_pages(page, 1 << order, 1); + kernel_poison_pages(page, 1 << order, 1); kasan_alloc_pages(page, order); if (gfp_flags & __GFP_ZERO) |