netdev - Re: [PATCH net-next] net: Silence false field-spanning write warning in ip_tunnel_info_opts

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <35791134-6c58-4cc4-a6ab-2965dce9cd4b@nvidia.com>
Date: Thu, 9 Jan 2025 11:00:24 +0200
From: Gal Pressman <gal@...dia.com>
To: Kees Cook <kees@...nel.org>, "David S. Miller" <davem@...emloft.net>,
 Jakub Kicinski <kuba@...nel.org>
Cc: netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
 Paolo Abeni <pabeni@...hat.com>, David Ahern <dsahern@...nel.org>,
 Simon Horman <horms@...nel.org>, linux-hardening@...r.kernel.org,
 Cosmin Ratiu <cratiu@...dia.com>
Subject: Re: [PATCH net-next] net: Silence false field-spanning write warning
 in ip_tunnel_info_opts_set() memcpy

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.