From: Przemek Kitszel <przemyslaw.kitszel@intel.com>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Kees Cook <keescook@chromium.org>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>,
Tony Nguyen <anthony.l.nguyen@intel.com>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
<intel-wired-lan@lists.osuosl.org>, <netdev@vger.kernel.org>,
<linux-hardening@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] overflow: Change DEFINE_FLEX to take __counted_by member
Date: Wed, 6 Mar 2024 08:06:29 +0100 [thread overview]
Message-ID: <bd21f7dc-9f89-40ee-895e-601c80165225@intel.com> (raw)
In-Reply-To: <9c2990f0-7407-49c6-9e3a-b92de82ea437@embeddedor.com>
On 3/6/24 04:25, Gustavo A. R. Silva wrote:
>
>
> On 05/03/24 19:07, Kees Cook wrote:
>> The norm should be flexible array structures with __counted_by
>> annotations, so DEFINE_FLEX() is updated to expect that. Rename
>> the non-annotated version to DEFINE_RAW_FLEX(), and update the few
>> existing users. Additionally add self-tests to validate syntax and
>> size calculations.
>>
>> Signed-off-by: Kees Cook <keescook@chromium.org>
>> ---
>
> [..]
Just a note that ice changes are purely mechanical, so this seems ok
to go via linux-hardening tree. And changes per-se are fine too :)
>
>> +/**
>> + * DEFINE_FLEX() - Define an on-stack instance of structure with a
>> trailing
>> + * flexible array member.
>> + *
>> + * @TYPE: structure type name, including "struct" keyword.
>> + * @NAME: Name for a variable to define.
>> + * @COUNTER: Name of the __counted_by member.
>> + * @MEMBER: Name of the array member.
>> + * @COUNT: Number of elements in the array; must be compile-time const.
>> + *
>> + * Define a zeroed, on-stack, instance of @TYPE structure with a
>> trailing
>> + * flexible array member.
>> + * Use __struct_size(@NAME) to get compile-time size of it afterwards.
>> + */
>> +#define DEFINE_FLEX(TYPE, NAME, COUNTER, MEMBER, COUNT) \
>
> Probably, swapping COUNTER and MEMBER is better?
right now we have usage scenario (from Kunits):
DEFINE_FLEX(struct foo, eight, counter, array, 8);
>
> DEFINE_FLEX(TYPE, NAME, MEMBER, COUNTER, COUNT)
usage would become:
DEFINE_FLEX(struct foo, eight, array, counter, 8);
which reads a bit better indeed, with the added benefit that we
go from broader to more specific:
whole struct -> array -> array size variable -> given array size
so +1 from me for the params swap
>
> Thanks
> --
> Gustavo
next prev parent reply other threads:[~2024-03-06 7:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 1:07 [PATCH] overflow: Change DEFINE_FLEX to take __counted_by member Kees Cook
2024-03-06 3:25 ` Gustavo A. R. Silva
2024-03-06 7:06 ` Przemek Kitszel [this message]
2024-03-06 23:52 ` Kees Cook
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