2023-10-03 23:18:42

by Kees Cook

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

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 protected]>
Cc: Jozsef Kadlecsik <[email protected]>
Cc: Florian Westphal <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <[email protected]>
---
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

2023-10-03 23:36:08

by Gustavo A. R. Silva

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

On 10/4/23 01:17, Kees Cook wrote:
> 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 protected]>
> Cc: Jozsef Kadlecsik <[email protected]>
> Cc: Florian Westphal <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

> ---
> 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);
> };
>
> /**