[PATCH v4 5/5] kasan: added functions for unpoisoning stack variables

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Alexander Potapenko <glider@xxxxxxxxxx>

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@xxxxxxxxxx>
[ghackmann@xxxxxxxxxx: fix memset() parameters, and tweak
 commit message to describe new callbacks]
Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
Signed-off-by: Paul Lawrence <paullawrence@xxxxxxxxxx>
---
 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

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]
  Powered by Linux