[PATCH RESEND net-next 2/2] KEYS: annotate struct user_key_payload with __counted_by

Add the __counted_by() compiler attribute to the flexible array member
'data' to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.

Signed-off-by: Thorsten Blum <[email protected]>
---
Resending this because patch 2/2 didn't go to netdev@ (Jakub)
Cc: [email protected]
---
 include/keys/user-type.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index 386c31432789..2305991f4fcd 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h
@@ -27,7 +27,8 @@
 struct user_key_payload {
 	struct rcu_head	rcu;		/* RCU destructor */
 	unsigned short	datalen;	/* length of this data */
-	char		data[] __aligned(__alignof__(u64)); /* actual data */
+	char		data[]		/* actual data */
+			__aligned(__alignof__(u64)) __counted_by(datalen);
 };
 
 extern struct key_type key_type_user;