kasan, slab: fix conflicts with CONFIG_HARDENED_USERCOPY

xairy · torvalds · commit 219667c23c68 · 2019-02-21T09:01:00.000-08:00
Similarly to commit 96fedce ("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>
diff --git a/mm/slab.c b/mm/slab.c
@@ -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);
