Commit 219667c2 authored Feb 20, 2019 by Andrey Konovalov Committed by Linus Torvalds Feb 21, 2019

kasan, slab: fix conflicts with CONFIG_HARDENED_USERCOPY

Similarly to commit 96fedce2 ("kasan: make tag based mode work with
CONFIG_HARDENED_USERCOPY"), we need to reset pointer tags in
__check_heap_object() in mm/slab.c before doing any pointer math.

Link: http://lkml.kernel.org/r/9a5c0f958db10e69df5ff9f2b997866b56b7effc.1550602886.git.andreyknvl@google.com


Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent dc15a8a2

mm/slab.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -4408,6 +4408,8 @@ void __check_heap_object(const void ptr, unsigned long n, struct page page,
		unsigned int objnr;
		unsigned long offset;

		ptr = kasan_reset_tag(ptr);

		/* Find and validate object. */
		cachep = page->slab_cache;
		objnr = obj_to_index(cachep, page, (void *)ptr);

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