Batch 1: Annotate structs with __counted_by

[PATCH 02/14] ipv4/igmp: Annotate struct ip_sf_socklist with __counted_by

Posted by Kees Cook 2 years, 2 months ago

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 checking 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 ip_sf_socklist.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/igmp.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/igmp.h b/include/linux/igmp.h
index ebf4349a53af..5171231f70a8 100644
--- a/include/linux/igmp.h
+++ b/include/linux/igmp.h
@@ -39,7 +39,7 @@ struct ip_sf_socklist {
 	unsigned int		sl_max;
 	unsigned int		sl_count;
 	struct rcu_head		rcu;
-	__be32			sl_addr[];
+	__be32			sl_addr[] __counted_by(sl_max);
 };
 
 #define IP_SFBLOCK	10	/* allocate this many at once */
-- 
2.34.1

Re: [PATCH 02/14] ipv4/igmp: Annotate struct ip_sf_socklist with __counted_by

Posted by Gustavo A. R. Silva 2 years, 2 months ago


On 9/22/23 11:28, 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 checking 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 ip_sf_socklist.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Martin KaFai Lau <martin.lau@kernel.org>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
-- 
Gustavo

> ---
>   include/linux/igmp.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/igmp.h b/include/linux/igmp.h
> index ebf4349a53af..5171231f70a8 100644
> --- a/include/linux/igmp.h
> +++ b/include/linux/igmp.h
> @@ -39,7 +39,7 @@ struct ip_sf_socklist {
>   	unsigned int		sl_max;
>   	unsigned int		sl_count;
>   	struct rcu_head		rcu;
> -	__be32			sl_addr[];
> +	__be32			sl_addr[] __counted_by(sl_max);
>   };
>   
>   #define IP_SFBLOCK	10	/* allocate this many at once */