diff options
| author | Laura Abbott <labbott@fedoraproject.org> | 2016-03-15 14:56:30 -0700 |
|---|---|---|
| committer | Vinayak Menon <vinmenon@codeaurora.org> | 2017-04-14 23:43:04 +0530 |
| commit | 2c00b603db67af40aa0b02c834cc58fec98d3023 (patch) | |
| tree | dcf7d9ea21e05af4e35dc59837811da8ff0a2b43 /include/linux | |
| parent | 5c69adad61e27f467fa8e1671633e455741e3fae (diff) | |
mm/page_poisoning.c: allow for zero poisoning
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
Change-Id: If7116e6bff246abbafc38bdfeb3601d3ea063ad2
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Acked-by: 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>
Git-commit: 1414c7f4f7d72d138fff35f00151d15749b5beda
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | include/linux/poison.h | 4 |
2 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 8e4e3debce84..d9fe27c8a57e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2149,10 +2149,12 @@ static inline void vm_stat_account(struct mm_struct *mm, #ifdef CONFIG_PAGE_POISONING extern bool page_poisoning_enabled(void); extern void kernel_poison_pages(struct page *page, int numpages, int enable); +extern bool page_is_poisoned(struct page *page); #else static inline bool page_poisoning_enabled(void) { return false; } static inline void kernel_poison_pages(struct page *page, int numpages, int enable) { } +static inline bool page_is_poisoned(struct page *page) { return false; } #endif #ifdef CONFIG_DEBUG_PAGEALLOC diff --git a/include/linux/poison.h b/include/linux/poison.h index 317e16de09e5..199ffec4bdf3 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -30,7 +30,11 @@ #define TIMER_ENTRY_STATIC ((void *) 0x74737461) /********** mm/debug-pagealloc.c **********/ +#ifdef CONFIG_PAGE_POISONING_ZERO +#define PAGE_POISON 0x00 +#else #define PAGE_POISON 0xaa +#endif /********** mm/slab.c **********/ /* |