2023-10-04 01:45:46

by Kees Cook

Subject: [PATCH] nexthop: Annotate struct nh_group 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 nh_group.

Cc: David Ahern <[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]
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <[email protected]>
---
include/net/nexthop.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/nexthop.h b/include/net/nexthop.h
index 8f5a2ab45920..d92046a4a078 100644
--- a/include/net/nexthop.h
+++ b/include/net/nexthop.h
@@ -126,7 +126,7 @@ struct nh_group {
bool has_v4;

struct nh_res_table __rcu *res_table;
- struct nh_grp_entry nh_entries[];
+ struct nh_grp_entry nh_entries[] __counted_by(num_nh);
};

struct nexthop {
--
2.34.1

2023-10-04 02:41:36

by David Ahern

Subject: Re: [PATCH] nexthop: Annotate struct nh_group with __counted_by

On 10/3/23 7:44 PM, 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 nh_group.
>
> Cc: David Ahern <[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]
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>
> ---
> include/net/nexthop.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>

Reviewed-by: David Ahern <[email protected]>

2023-10-06 10:00:41

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] nexthop: Annotate struct nh_group with __counted_by

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <[email protected]>:

On Tue, 3 Oct 2023 18:44:49 -0700 you 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 nh_group.
>
> [...]

Here is the summary with links:
- nexthop: Annotate struct nh_group with __counted_by
https://git.kernel.org/netdev/net-next/c/2a92fccdaca8

You are awesome, thank you!
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