Subject: [PATCH] netfilter: nf_tables: Annotate struct nft_pipapo_match with __counted_by

From: Kees Cook <[email-masked]>
Date: Tue, 3 Oct 2023 16:17:51 -0700

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct nft_pipapo_match.

Cc: Pablo Neira Ayuso <[email-masked]>
Cc: Jozsef Kadlecsik <[email-masked]>
Cc: Florian Westphal <[email-masked]>
Cc: "David S. Miller" <[email-masked]>
Cc: Eric Dumazet <[email-masked]>
Cc: Jakub Kicinski <[email-masked]>
Cc: Paolo Abeni <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Cc: [email-masked]
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <[email-masked]>
---
 net/netfilter/nft_set_pipapo.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nft_set_pipapo.h b/net/netfilter/nft_set_pipapo.h
index 25a75591583e..2e164a319945 100644
--- a/net/netfilter/nft_set_pipapo.h
+++ b/net/netfilter/nft_set_pipapo.h
@@ -147,7 +147,7 @@ struct nft_pipapo_match {
 	unsigned long * __percpu *scratch;
 	size_t bsize_max;
 	struct rcu_head rcu;
-	struct nft_pipapo_field f[];
+	struct nft_pipapo_field f[] __counted_by(field_count);
 };
 
 /**
-- 
2.34.1