[20/43] instrumented.h: add KMSAN support

Commit Message

Alexander Potapenko Dec. 14, 2021, 4:20 p.m. UTC

To avoid false positives, KMSAN needs to unpoison the data copied from
the userspace. To detect infoleaks - check the memory buffer passed to
copy_to_user().

Signed-off-by: Alexander Potapenko <[e-mail]>
---
Link: https://linux-review.googlesource.com/id/I43e93b9c02709e6be8d222342f1b044ac8bdbaaf
---
 include/linux/instrumented.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Patch

diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
index ee8f7d17d34f5..c73c1b19e9227 100644
--- a/include/linux/instrumented.h
+++ b/include/linux/instrumented.h
@@ -2,7 +2,7 @@ 
 
 /*
  * This header provides generic wrappers for memory access instrumentation that
- * the compiler cannot emit for: KASAN, KCSAN.
+ * the compiler cannot emit for: KASAN, KCSAN, KMSAN.
  */
 #ifndef _LINUX_INSTRUMENTED_H
 #define _LINUX_INSTRUMENTED_H
@@ -10,6 +10,7 @@ 
 #include <linux/compiler.h>
 #include <linux/kasan-checks.h>
 #include <linux/kcsan-checks.h>
+#include <linux/kmsan-checks.h>
 #include <linux/types.h>
 
 /**
@@ -117,6 +118,7 @@  instrument_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
 	kasan_check_read(from, n);
 	kcsan_check_read(from, n);
+	kmsan_copy_to_user(to, from, n, 0);
 }
 
 /**
@@ -151,6 +153,7 @@  static __always_inline void
 instrument_copy_from_user_after(const void *to, const void __user *from,
 				unsigned long n, unsigned long left)
 {
+	kmsan_unpoison_memory(to, n - left);
 }
 
 #endif /* _LINUX_INSTRUMENTED_H */