From: Paul Lawrence <paullawrence@google.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, linux-kbuild@vger.kernel.org,
Matthias Kaehlcke <mka@chromium.org>,
Michael Davidson <md@google.com>,
Greg Hackmann <ghackmann@google.com>,
Paul Lawrence <paullawrence@google.com>
Subject: [PATCH v3 5/5] kasan: added functions for unpoisoning stack variables
Date: Fri, 1 Dec 2017 13:36:43 -0800 [thread overview]
Message-ID: <20171201213643.2506-6-paullawrence@google.com> (raw)
In-Reply-To: <20171201213643.2506-1-paullawrence@google.com>
From: Alexander Potapenko <glider@google.com>
As a code-size optimization, LLVM builds since r279383 may
bulk-manipulate the shadow region when (un)poisoning large memory
blocks. This requires new callbacks that simply do an uninstrumented
memset().
This fixes linking the Clang-built kernel when using KASAN.
Signed-off-by: Alexander Potapenko <glider@google.com>
[ghackmann@google.com: fix memset() parameters, and tweak
commit message to describe new callbacks]
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Paul Lawrence <paullawrence@google.com>
---
mm/kasan/kasan.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index d96b36088b2f..8aaee42fcfab 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -770,6 +770,21 @@ void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
}
EXPORT_SYMBOL(__asan_allocas_unpoison);
+/* Emitted by the compiler to [un]poison local variables. */
+#define DEFINE_ASAN_SET_SHADOW(byte) \
+ void __asan_set_shadow_##byte(const void *addr, size_t size) \
+ { \
+ __memset((void *)addr, 0x##byte, size); \
+ } \
+ EXPORT_SYMBOL(__asan_set_shadow_##byte)
+
+DEFINE_ASAN_SET_SHADOW(00);
+DEFINE_ASAN_SET_SHADOW(f1);
+DEFINE_ASAN_SET_SHADOW(f2);
+DEFINE_ASAN_SET_SHADOW(f3);
+DEFINE_ASAN_SET_SHADOW(f5);
+DEFINE_ASAN_SET_SHADOW(f8);
+
#ifdef CONFIG_MEMORY_HOTPLUG
static int __meminit kasan_mem_notifier(struct notifier_block *nb,
unsigned long action, void *data)
--
2.15.0.531.g2ccb3012c9-goog
next prev parent reply other threads:[~2017-12-01 21:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-01 21:36 [PATCH v3 0/5] kasan: support alloca, LLVM Paul Lawrence
2017-12-01 21:36 ` [PATCH v3 1/5] kasan: add compiler support for clang Paul Lawrence
2017-12-01 21:36 ` [PATCH v3 2/5] kasan/Makefile: Support LLVM style asan parameters Paul Lawrence
2017-12-04 16:14 ` Andrey Ryabinin
[not found] ` <CAL=UVf7LO5BDWVEeLXLkrLDBxwV0aO2sLv_htkpcL_Gp7sT07Q@mail.gmail.com>
2017-12-04 16:55 ` Andrey Ryabinin
2017-12-01 21:36 ` [PATCH v3 3/5] kasan: support alloca() poisoning Paul Lawrence
2017-12-03 12:23 ` Dmitry Vyukov
2017-12-04 16:42 ` Christoph Hellwig
2017-12-04 16:55 ` Andrey Ryabinin
2017-12-04 17:09 ` Andrey Ryabinin
2017-12-01 21:36 ` [PATCH v3 4/5] kasan: Add tests for alloca poisonong Paul Lawrence
2017-12-01 21:36 ` Paul Lawrence [this message]
2017-12-03 12:24 ` [PATCH v3 0/5] kasan: support alloca, LLVM Dmitry Vyukov
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