Alexander Potapenko 19e85d9390 kmsan: do not wipe out origin when doing partial unpoisoning ... commit 2ef3cec44c upstream. As noticed by Brian, KMSAN should not be zeroing the origin when unpoisoning parts of a four-byte uninitialized value, e.g.: char a[4]; kmsan_unpoison_memory(a, 1); This led to false negatives, as certain poisoned values could receive zero origins, preventing those values from being reported. To fix the problem, check that kmsan_internal_set_shadow_origin() writes zero origins only to slots which have zero shadow. Link: https://lkml.kernel.org/r/20240528104807.738758-1-glider@google.com Fixes: f80be4571b ("kmsan: add KMSAN runtime core") Signed-off-by: Alexander Potapenko <glider@google.com> Reported-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com> Link: https://lore.kernel.org/lkml/20240524232804.1984355-1-bjohannesmeyer@gmail.com/T/ Reviewed-by: Marco Elver <elver@google.com> Tested-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-06-16 13:47:41 +02:00
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Makefile	kmsan: disable ftrace in kmsan core code	2023-02-20 12:46:16 -08:00
core.c	kmsan: do not wipe out origin when doing partial unpoisoning	2024-06-16 13:47:41 +02:00
hooks.c	mm: kmsan: use helper macro offset_in_page()	2023-08-21 13:37:29 -07:00
init.c	mm, treewide: introduce NR_PAGE_ORDERS	2024-05-02 16:32:41 +02:00
instrumentation.c	kasan,kmsan: remove __GFP_KSWAPD_RECLAIM usage from kasan/kmsan	2023-06-23 16:59:26 -07:00
kmsan.h	kmsan: core: kmsan_in_runtime() should return true in NMI context	2022-11-08 15:57:24 -08:00
kmsan_test.c	printk: export console trace point for kcsan/kasan/kfence/kmsan	2023-04-18 16:30:11 -07:00
report.c	…
shadow.c	mm: kmsan: use helper macros PAGE_ALIGN and PAGE_ALIGN_DOWN	2023-08-21 13:37:29 -07:00