From: Kees Cook <kees@kernel.org>
To: Gal Pressman <gal@nvidia.com>
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: Thu, 9 Jan 2025 08:52:50 -0800 [thread overview]
Message-ID: <202501090852.AA32AF8BD@keescook> (raw)
In-Reply-To: <35791134-6c58-4cc4-a6ab-2965dce9cd4b@nvidia.com>
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?)
-Kees
--
Kees Cook
next prev parent reply other threads:[~2025-01-09 16:52 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 [this message]
2025-01-12 6:37 ` Gal Pressman
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