16 Mar, 2016

2 commits

• 1414c7f4f   mm/page_poisoning.c: allow for zero poisoning ... Browse Code »

  By default, page poisoning uses a poison value (0xaa) on free. If this
  is changed to 0, the page is not only sanitized but zeroing on alloc
  with __GFP_ZERO can be skipped as well. The tradeoff is that detecting
  corruption from the poisoning is harder to detect. This feature also
  cannot be used with hibernation since pages are not guaranteed to be
  zeroed after hibernation.

  Credit to Grsecurity/PaX team for inspiring this work

  Signed-off-by: Laura Abbott
  Acked-by: Rafael J. Wysocki
  Cc: "Kirill A. Shutemov"
  Cc: Vlastimil Babka
  Cc: Michal Hocko
  Cc: Kees Cook
  Cc: Mathias Krause
  Cc: Dave Hansen
  Cc: Jianyu Zhan
  Signed-off-by: Andrew Morton
  Signed-off-by: Linus Torvalds

  Laura Abbott

  2016-03-16 07:55:16 +0800  
• 8823b1dbc   mm/page_poison.c: enable PAGE_POISONING as a separate option ... Browse Code »

  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
  Cc: Rafael J. Wysocki
  Cc: "Kirill A. Shutemov"
  Cc: Vlastimil Babka
  Cc: Michal Hocko
  Cc: Kees Cook
  Cc: Mathias Krause
  Cc: Dave Hansen
  Cc: Jianyu Zhan
  Signed-off-by: Andrew Morton
  Signed-off-by: Linus Torvalds

  Laura Abbott

  2016-03-16 07:55:16 +0800