From: Gal Pressman <gal@nvidia.com>
To: Kees Cook <kees@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, David Ahern <dsahern@kernel.org>,
Simon Horman <horms@kernel.org>,
linux-hardening@vger.kernel.org, Cosmin Ratiu <cratiu@nvidia.com>
Subject: Re: [PATCH net-next] net: Silence false field-spanning write warning in ip_tunnel_info_opts_set() memcpy
Date: Sun, 12 Jan 2025 08:37:43 +0200 [thread overview]
Message-ID: <cb27ef1b-d316-42ed-8781-69bef7dc76b8@nvidia.com> (raw)
In-Reply-To: <202501090852.AA32AF8BD@keescook>
On 09/01/2025 18:52, Kees Cook wrote:
> On Thu, Jan 09, 2025 at 11:00:24AM +0200, Gal Pressman wrote:
>> On 08/01/2025 1:28, Kees Cook wrote:
>>>> This resolves the following warning:
>>>> memcpy: detected field-spanning write (size 8) of single field "_Generic(info, const struct ip_tunnel_info * : ((const void *)((info) + 1)), struct ip_tunnel_info * : ((void *)((info) + 1)) )" at include/net/ip_tunnels.h:662 (size 0)
>>>
>>> Then you can drop this macro and just use: info->options
>>>
>>> Looks like you'd need to do it for all the types in struct metadata_dst, but at least you could stop hiding it from the compiler. :)
>>
>> Can you please explain the "do it for all the types in struct
>> metadata_dst" part?
>> AFAICT, struct ip_tunnel_info is the only one that's extendable, I don't
>> think others need to be modified.
>
> Ah, sorry. If that's the case, then just ip_tunnel_info is fine. (Is all
> of the metadata_dst trailing byte allocation logic just for
> ip_tunnel_info?)
Yes, thanks again!
prev parent reply other threads:[~2025-01-12 6:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-07 16:55 [PATCH net-next] net: Silence false field-spanning write warning in ip_tunnel_info_opts_set() memcpy Gal Pressman
2025-01-07 23:28 ` Kees Cook
2025-01-08 6:56 ` Gal Pressman
2025-01-09 9:00 ` Gal Pressman
2025-01-09 16:52 ` Kees Cook
2025-01-12 6:37 ` Gal Pressman [this message]
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