Date: Thu, 28 Jan 2016 18:38:17 -0800 From: Laura Abbott <labbott@...oraproject.org> To: Andrew Morton <akpm@...ux-foundation.org>, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Vlastimil Babka <vbabka@...e.cz>, Michal Hocko <mhocko@...e.com> Cc: Laura Abbott <labbott@...oraproject.org>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com, Kees Cook <keescook@...omium.org> Subject: [PATCHv2 0/2] Sanitization of buddy pages Hi, This is v2 of the series to add sanitization to the buddy allocator. The standard sanitization blurb: For those who aren't familiar with this, the goal of sanitization is to reduce the severity of use after free and uninitialized data bugs. Memory is cleared on free so any sensitive data is no longer available. Discussion of sanitization was brough up in a thread about CVEs (lkml.kernel.org/g/<20160119112812.GA10818@...nda>) Changes since v1: - Squashed the refactor and adding the poisoning together. Having them separate didn't seem to give much extra benefit and lead to some churn as well. - Corrected the order of poison vs. kernel_map in the alloc path - zeroing can now be enabled with hibernation (enabling zero poisoning turns off hibernation) - Added additional checks for skipping __GFP_ZERO. On SPARSEMEM systems the extended page flags are not initialized until after memory is freed to the buddy list which prevents the pages from being zeroed on first free via poisoning. This does also mean that any residual data that may be left in the pages from boot up will not be cleared which is a risk. I'm open to suggestions for fixing or it can be future work. - A few spelling/checkpatch fixes. - Addressed comments from Dave Hansen and Jianyu Zhan - This series now depends on the change to allow debug_pagealloc_enabled to be used without !CONFIG_DEBUG_PAGEALLOC (http://article.gmane.org/gmane.linux.kernel.mm/145208) Thanks, Laura Laura Abbott (2): mm/page_poison.c: Enable PAGE_POISONING as a separate option mm/page_poisoning.c: Allow for zero poisoning Documentation/kernel-parameters.txt | 5 + include/linux/mm.h | 15 +++ include/linux/poison.h | 4 + kernel/power/hibernate.c | 17 ++++ mm/Kconfig.debug | 36 ++++++- mm/Makefile | 2 +- mm/debug-pagealloc.c | 137 --------------------------- mm/page_alloc.c | 13 ++- mm/page_ext.c | 10 +- mm/page_poison.c | 184 ++++++++++++++++++++++++++++++++++++ 10 files changed, 281 insertions(+), 142 deletions(-) delete mode 100644 mm/debug-pagealloc.c create mode 100644 mm/page_poison.c -- 2.5.0
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